Search

To investigate the effect of CT image acquisition parameters on the performance of radiomics in classifying benign and malignant pulmonary nodules (PNs) with respect to nodule size. We retrospectively collected CT images of 696 patients with PNs from March 2015 to March 2018. PNs were grouped by nodule diameter: T1a (diameter ≤ 1.0 cm), T1b (1.0 cm

Retrospective cohort. The objective of the study is to evaluate a relationship between idiopathic intracranial hypertension (IIH) and superior semicircular canal dehiscence (SSCD) of bone overlying the superior semicircular canal (SSC). A total of 57 (114 ears) individuals, 20 of whom were controls and 37 of whom were IIH, were included in the study. Individuals were evaluated with 0.8 mm slice thickness computed tomography (CT) images for SSC bony roof thickness and SSCD. Thickness of the bony roof over the SSC was graded from Grade 1 to Grade 4. Grade 3 was defined as pre-dehiscence and Grade 4 as dehiscence. Bony roof thickness was 1.25 mm in the control group and 0.76 mm in the IIH group. When bony roof thickness was compared between the groups, it was found to be significantly thinner in the IIH group (p = 0.012). In the IIH group, while dehiscence was detected in 25 of 74 ears, no dehiscence was detected in 49 ears. In the control group, while dehiscence was detected in 5 ears, no dehiscence was detected in 35 ears. The difference is statistically significant (p = 0.015). The correlation between bony roof thickness and cerebrospinal fluid (CSF) pressure in the IIH group was not statistically significant (p = 0.343; rho = 0.110). The correlation between bony roof thickness and age in the IIH group was not statistically significant (p = 0.082; rho = − 0.164). Increased CSF pressure in patients with IIH may cause chronic, progressive, and irreversible damage to the bone of the SSC and, according to our study, the rate of SSCD was found to be high in IIH patients.

Early and intermediate age-related macular degeneration (AMD) results in drusen deposits under the retinal pigment epithelium (RPE). These early stages of AMD exhibit different risks of progressing to late AMD. To date, early AMD has been classified and quantified by fundus photography. This does not appear to be sensitive enough for clinical trials studying the impact on drusen. SD-OCT with two-dimensional rendering of the segmented slices analysed allows for en face imaging of the drusen. The present trial studied the potential of quantifying early and intermediate AMD by en-face optical coherence tomography (OCT).Thirty-one eyes of 29 patients in different stages of early and intermediate AMD were studied. To this end, fundus photographs (Kowa VX-10i, Kowa, Tokyo, Japan) and en-face OCT images (RTVue XR Avanti, Optovue, Inc., Fremont, CA, USA) were taken. First, different segmentation levels (6 µm underneath the RPE, on the RPE, 6 µm and 9 µm above the RPE) and different layer thicknesses (5 µm, 10 µm, 20 µm and 30 µm) were analysed to determine the best segmentation for visualising drusen. Drusen were marked manually and their number and surface area calculated. This analysis was then compared with the standardised drusen analyses on fundus photography. Additional changes in early and intermediate AMD such as pigment epithelial detachments (PEDs) and subretinal drusenoid deposits (SDD) as well as small atrophies were also documented and compared.The best segmentation for delineating the drusen on the en-face OCT images was found to be a segmentation 6 µm underneath the RPE with a slice thickness of 20 µm. Comparison of drusen quantification on en-face OCT images with the standardised drusen analysis on fundus photography revealed particularly good similarity. Other changes in early and intermediate AMD, such as PEDs, SDD and small atrophies, were easier to assess on the en-face OCT images.The analysis and quantification of drusen from en-face OCT images with 20 µm segmentation at 6 µm underneath the RPE allows differentiated quantification of various drusen characteristics. Moreover, other changes in early and intermediate AMD can also be analysed. In future observational and clinical trials, this could help quantify drusen.Bei der frühen und intermediären altersabhängigen Makuladegeneration (AMD) kommt es zu Ablagerungen unterhalb des retinalen Pigmentepithels (RPE) in Form von Drusen. Diese frühen Stadien der AMD beinhalten ein unterschiedliches Risiko zur Entwicklung einer späten AMD. Bisher erfolgte die Klassifizierung und Quantifizierung der frühen AMD anhand von Fundusfotos. Für klinische Studien, welche die Beeinflussung von Drusen überprüfen, erscheint dies zu wenig sensitiv. Das SD-OCT mit flächiger Darstellung segmentierter Analyseschichten ermöglicht eine En-face-Darstellung der Drusen. In der vorliegenden Studie wurden die Möglichkeiten einer Quantifizierung der frühen und intermediären AMD mit dem Verfahren des En-face-OCT untersucht.Es wurden 31 Augen von 29 Patienten mit früher und intermediärer AMD untersucht. Hierzu wurden Fundusfotos (Kowa VX-10i, Kowa, Tokyo, Japan) und En-face-OCT-Aufnahmen (RTVue XR Avanti, Optovue, Inc., Freemont, CA, USA) erstellt. Zunächst wurden verschiedene Schnittebenen (6 µm unterhalb des RPE, auf dem RPE, 6 µm und 9 µm oberhalb des RPE) und unterschiedlichen Schichtdicken (5, 10, 20 und 30 µm) analysiert, um die beste Segmentierung zur Darstellung der Drusen zu bestimmen. Die Drusen wurden manuell markiert und die Anzahl und Fläche berechnet. Diese Analyse wurde mit den standardisierten Drusenanalysen auf Fundusfotos verglichen. Zusätzliche Veränderungen einer frühen und intermediären AMD wie Pigmentepithelabhebungen (PEDs) und Subretinal drusenoid Deposits (SDD) sowie kleine Atrophien wurden ebenso dokumentiert und verglichen.Als beste Segmentierung zur Abgrenzung der Drusen auf den En-face-OCT-Aufnahmen konnte eine Segmentierung 6 µm unterhalb RPE mit einer Schnittdicke von 20 µm gefunden werden. Der Vergleich der Drusenquantifizierung auf En-face-OCT-Aufnahmen mit der standardisierten Drusenanalyse auf Fundusfotos zeigte eine sehr gute Vergleichbarkeit. Andere Veränderungen der frühen und intermediären AMD, wie PEDs, SDD und kleine Atrophien, waren auf den En-face-OCT-Aufnahmen besser beurteilbar.Die Analyse und Quantifizierung von Drusen auf En-face-OCT-Aufnahmen mit einer 20-µm-Segmentierung 6 µm unterhalb des RPE ermöglicht eine differenzierte Quantifizierbarkeit verschiedener Drusencharakteristika. Zudem können auch weitere Veränderungen der frühen und intermediären AMD analysiert werden. Dies könnte in zukünftigen Beobachtungs- und Behandlungsstudien zur Quantifizierung von Drusen eingesetzt werden.

Coronary artery calcium (CAC) is a strong predictor for future cardiovascular events. Traditionally CAC has been quantified using the Agatston score, which was developed in the late 1980s for electron beam tomography (EBT). While EBT has been completely replaced by modern multiple-detector row CT technology, the traditional CAC scoring method by Agatston remains in use, although the literature indicates suboptimal reproducibility and subjects being incorrectly classified. The traditional Agatston scoring method counteracts the technical advances of CT technology, and prevents the use of thinner sections, obtained at lower tube voltage and overall decreased radiation exposure that has become available to other CT applications. Moreover, recent studies have shown that not only the total amount of CAC, but also its density and distribution in the coronary arterial tree may be of prognostic value. Acquisition and reconstruction techniques thus need to be adapted for modern CT technology and optimized for CAC quantification. In this review we describe the technical limitations of the Agatston score followed by our suggestions for developing a new and more robust CAC quantification method.

BACKGROUND: Assimilating diagnostic radiology education into undergraduate medical education remains a challenge. This challenge places a greater emphasis in surgical residency to ensure this education occurs. The objective of this study is to determine whether a 3D-reconstruction may improve surgical residents’ assessment of resectability of pancreatic lesions METHODS: Four cases were identified of patients with a pancreatic lesion; high-quality, triphasic abdominal CT scans were obtained and evaluated to ensure sufficient resolution and slice thickness. The images then were used for 3D-reconstruction of the cases. RESULTS: PGY3–5 residents had a statistically-significant higher percentage of correct answers on objective questionnaire items using CT in conjunction with 3D-reconstruction software versus CT only. PGY1–2 residents had a higher percentage of correct answers using 3D-reconstruction software, but the difference was not statistically significant. statistically significant. CONCLUSIONS: 3D-reconstruction software could be a viable tool to augment radiology education within a surgery residency, especially in CT interpretation, but there appears to be a minimum threshold of knowledge needed for meaningful improvement; therefore, this software may be more useful for PGY3–5 residents than PGY1–2 residents.

Background: The concept of adipose tissue radiodensity is emerging and its relationship to disease prognosis has been infrequently explored. The aims of the present study were to evaluate published literature that explored adipose tissue radiodensity in relation to outcomes in health and disease and to summarize methodologies used to evaluate adipose tissue radiodensity by computed tomography (CT). Methods: A comprehensive literature review included all published studies that applied CT imaging of the abdominal region to define adipose tissue radiodensity. The review was performed without regard for study design or quality. Results: We identified 22 studies that evaluated the relationship between adipose tissue radiodensity and outcomes. The literature reviewed highlights significant methodological variation in terms of abdominal region selected, slice thickness, contrast media, dose, software, and radiodensity ranges used to define adipose tissues. This is primarily due to a lack of consensus about the effect such methodological variables have on body composition parameters. Conclusions: Authors should carefully report adipose tissue radiodensity, especially when it comes to prognosis inference. Consensus on methodology will enable meaningful advancement in understanding the importance of adipose tissue radiodensity in different disease conditions.

The purpose of this study was to evaluate the diagnostic accuracy of patent with ductus arteriosus (PDA) based on the availability of pretest information on routine chest CT with 3 mm slice-thickness. We retrospectively evaluated CT of 64 patients with PDA. The enrolled patients were categorized as group 1 (presence of pretest information) and 2 (absence of pretest information, silent PDA). CTs were read by eleven board-certified radiologists, and subsequently by two blind readers. We investigated whether a PDA was mentioned on the initial CT reading. Correct diagnosis of PDA was made in all patients with group 1 (n = 42). In contrast, only 13.7% were correctly diagnosed in group 2. All cases of missed PDA in group 2 were also missed by two blind readers. It is important to realize that the diagnostic accuracy of silent PDA is poor on the chest CT with 3 mm slice-thickness. Thus, use of axial CT images with the thinnest slice-thickness and multi-planar reformatted images (i.e., sagittal and coronal images) may be one way to reduce the number of missed PDA.

The article presents the cases observed in the practice of the Office of medico-legal examinations of the Moscow Region when computed tomography (CT) was used for the first time in Russia for pre-autopsy examination (virtual autopsy) of three corpses with gunshot wounds followed by imaging-anatomical comparison of the results.Objectives. Determination of the injury volume, visualization of the wound tracts, localization of the bullets.Material and methods. Computed tomography was performed in radiology department using CT Scanner Hitachi Eclos‑16 (16 slices per rotation, slice thickness 1.5 and 2.0 mm) followed by multi-planar reconstruction of the images.Results. 3D reconstruction of the CT scans of the corpses has visualized the whole volume of the trauma. Firearm perforating skull fractures, crushing injuries of the brain, injuries of the thoracic and abdominal organs along the wound tracks, bullets at the ends of the blind wound tracks were revealed on CT-scans.Conclusion. Pre-autopsy CT with 3D-reconstruction has allowed to determine localization of the bullets in the bodies accurately. This allowed to choose the optimal examination tactics in each particular case and provided invaluable assistance in the search for the bullets. Virtopsy in the cases of firearm injury has great diagnostic opportunities in visualization and 3D presentation of the wound tracks and their direction. 3D CT has recorded the original position and characteristics of the skull fractures under the undamaged tissues. The authors made the assumption that a virtual autopsy could be a reliable alternative to traditional autopsy in the foreseeable future in cases of firearm injuries.

Background It is difficult to examine mild to moderate feline intra-thoracic lymphadenopathy via and thoracic radiography. Despite previous information from computed tomographic (CT) images of intra-thoracic lymph nodes, some factors from animals and CT setting were less elucidated. Therefore, this study aimed to investigate the effect of internal factors from animals and external factors from the CT procedure on the feasibility to detect the intra-thoracic lymph nodes. Twenty-four, client-owned, clinically healthy cats were categorized into three groups according to age. They underwent pre- and post-contrast enhanced CT for whole thorax followed by inter-group evaluation and comparison of sternal, cranial mediastinal, and tracheobronchial lymph nodes. Results Post contrast-enhanced CT appearances revealed that intra-thoracic lymph nodes of kittens were invisible, whereas the sternal, cranial mediastinal, and tracheobronchial nodes of cats aged over 7 months old were detected (6/24, 9/24 and 7/24, respectively). Maximum width of these lymph nodes were 3.93 ± 0.74 mm, 4.02 ± 0.65 mm, and 3.51 ± 0.62 mm, respectively. By age, lymph node sizes of these cats were not significantly different. Transverse lymph node width of males was larger than that of females (P = 0.0425). Besides, the detection score of lymph nodes was affected by slice thickness (P P = 0.0049). Furthermore, an irregular, soft tissue structure, possibly the thymus, was detected in all juvenile cats and three mature cats. Conclusions Despite additional information on intra-thoracic lymph nodes in CT images, which can be used to investigate lymphatic-related abnormalities, age, sex, and slice thickness of CT images must be also considered.

Cross-institutional establishment of standardized protocols for CT and MR imaging of primary liver and pancreas tumors in an oncological center. This prospective dual-institution study was approved by the local IRBs. Minimum requirements (phases, sequences, slice thickness) for imaging of primary liver and pancreas tumors were defined and implemented at both sites. Between 06/19 and 08/19 in-house examinations were evaluated in terms of compliance with defined protocols and image quality. In addition, extramural examinations that were demonstrated at interdisciplinary tumor board meetings in the same study period were reviewed. Results were analyzed by means of descriptive statistics, and differences between centers, modalities and organs assessed (Fisher-exact Test, p 0.05 deemed significant). 480 data sets (397 internal, 83 extramural) were included in this study and analyzed. Overall protocol compliance for in-house examinations was 93.5 % (371/397 datasets), without statistical significant difference between the two institutions (p = 0.0615). External studies met minimum requirements in 48.2 % (40/83 datasets). Regarding in-house imaging, significant differences were observed between CT of the liver and the pancreas (p 0.05) and between CT and MRI of the pancreas (p 0.05). As demonstrated in this pilot project, cross-institutional establishment of standardized imaging protocols is feasible with a compliance rate of more than 90 %. Standardized imaging protocols may serve as a quality indicator in oncological imaging, and over time, improve cross-institutional patient care. · Cross-institutional establishment of standardized imaging protocols is feasible with high compliance.. · Standards may serve as a quality indicator in oncological imaging.. · In perspective, cross-institutional patient care may be improved..· Römermann I, Al-Bourini O, Seif Amir Hosseini A et al. Cross-insitutional standardization of imaging protocols - A pilot study within the scope of the Comprehensive Cancer Center Lower Saxony. Fortschr Röntgenstr 2021; 193: 410 - 416.ZIEL: Standortübergreifende Etablierung von standardisierten Untersuchungsprotokollen für die Bildgebung von primären Leber- und Pankreastumoren in der CT und MRT in einem onkologischen Zentrum. Diese biinstitutionelle prospektive Beobachtungsstudie wurde durch die Ethikkommission der beteiligten Institute genehmigt. Minimalanforderungen (Phasen, Sequenzen, Schichtdicke) für die CT- und MRT-Bildgebung von primären Leber- und Pankreastumoren wurden definiert und in den Instituten implementiert. Im Zeitraum von 06/19 bis 08/19 wurden an beiden Standorten die institutionsinternen Datensätze von Patienten mit entsprechender klinischer Fragestellung im Hinblick auf Einhaltung definierter Protokolle und Bildqualität ausgewertet. Zusätzlich erfolgte die Begutachtung von externen Untersuchungen, welche im selben Zeitraum im Rahmen interdisziplinärer Tumorkonferenzen demonstriert wurden. Die Ergebnisse wurden mittels deskriptiver Statistik ausgewertet und Unterschiede zwischen den Instituten, Modalitäten und Organen mittels Fisher-exakt-Test erfasst (p 0,05 signifikant). Insgesamt wurden 480 Datensätze (397 interne, 83 externe) in die Studie eingeschlossen und ausgewertet. Die Einhaltung der definierten Protokolle für die internen Untersuchungen lag übergreifend an beiden Instituten bei 93,5 % (371/397 Datensätze), ohne signifikanten Unterschied zwischen den beiden Instituten (p = 0,0615). Die externen Untersuchungen erfüllten in 48,2 % (40/83 Datensätze) die Minimalanforderungen. Zentrumsintern waren signifikante Unterschiede zwischen CT-Untersuchungen der Leber und des Pankreas nachweisbar (p 0,05) sowie zwischen Untersuchungen des Pankreas in der CT und MRT (p 0,05). Eine institutionsübergreifende Standardisierung von Untersuchungsprotokollen ist möglich, wie in diesem Pilotprojekt gezeigt werden konnte, mit der Einhaltung definierter Protokolle in über 90 %. Untersuchungsstandards können als Qualitätsindikator für die onkologische Bildgebung dienen und perspektivisch die zentrumsübergreifende Patientenversorgung verbessern.· Eine standortübergreifende Standardisierung von Untersuchungsprotokollen ist mit hoher Protokoll-Einhaltungsrate möglich.. · Untersuchungsstandards können als Qualitätsindikator für die onkologische Bildgebung dienen.. · Perspektivisch kann die zentrumsübergreifende Patientenversorgung verbessert werden..· Römermann I, Al-Bourini O, Seif Amir Hosseini A et al. Cross-insitutional standardization of imaging protocols – A pilot study within the scope of the Comprehensive Cancer Center Lower Saxony. Fortschr Röntgenstr 2021; 193: 410 – 416.

To investigate whether CT slice thickness influences the performance of radiomics prognostic models in non-small-cell lung cancer (NSCLC) patients. CT images including 1-, 3-, and 5-mm slice thicknesses acquired from 311 patients who underwent surgical resection for NSCLC between May 2014 and December 2015 were evaluated. Tumor segmentation was performed on CT of each slice thickness and total 94 radiomics features (shape, tumor intensity, and texture) were extracted. The study population was temporally split into development (n = 185) and validation sets (n = 126) for prediction of disease-free survival (DFS). Three radiomics models were built from three different slice thickness datasets (Rad-1, Rad-3, and Rad-5), respectively. Model performance was assessed and compared in three slice thickness datasets and mixed slice thickness dataset using C-indices. In corresponding slice thickness datasets, the C-indices of Rad-1, Rad-3, and Rad-5 for prediction of DFS were 0.68, 0.70, and 0.68 in the development set, and 0.73, 0.73, and 0.76 in the validation set (p = 0.40–0.89 and 0.27–0.90, respectively). Performance of the models was not significantly changed when they were applied to different slice thicknesses data in the validation set (C-index, 0.73–0.76, 0.72–0.73, 0.75–0.76; p = 0.07–0.92). In the mixed slice thickness dataset, performances of the models were similar to or slightly lower than their performances in the corresponding slice thickness datasets (C-index, 0.72–0.75 vs. 0.73–0.76) in the validation set. The performance of radiomics models for predicting DFS in NSCLC patients was not significantly affected by CT slice thickness. • Three radiomics models based on 1-, 3-, and 5-mm CT datasets showed C-indices for predicting disease-free survival of 0.68–0.70 in the development set and 0.73–0.76 in the validation set, without statistical differences (p = 0.27–0.90). • Application of the radiomics models to different slice thickness datasets showed no significant differences in performance between the values in the prediction of disease-free survival (p = 0.07–0.99). • Three radiomics models based on 1-, 3-, and 5-mm CT datasets performed well in mixed slice thickness datasets, showing similar or slightly lower performances.

Background Cerebral microbleeds (CMBs) are refined neuroimaging findings detected on T2*-weighted gradient echo (GRE) magnetic resonance imaging (MRI) and are widely accepted as an important marker of the vulnerability of cerebral small vessels. It is necessary to further clarify the natural history of CMBs by a longitudinal study. This study aimed to reveal the natural history of CMBs and find a better way to track CMBs by a prospective long-term observation. Methods We performed yearly brain MRI assessments for 7 or more years in 8 nonvalvular atrial fibrillation Japanese outpatients with CMBs detected in the baseline MRI. We began to use a 3.0T MRI scanner from 2012 as well. Results We followed up 3 patients for 9 years, 2 for 8 years, and 3 for 7 years. In all patients, the CMBs at baseline did not disappear during the follow-up period. Importantly, the CMB in 1 patient seemed to disappear during the sixth imaging using 1.5T T2*-weighted GRE but was detected again during the seventh imaging with 3.0T susceptibility weighted imaging and ninth imaging with 3.0T T2* GRE. Moreover, in a patient implanted with a pacemaker, which is only applicable for 1.5T MRI at present, the CMB seemed to disappear and appeared once again with a 1.5T T2*-weighted GRE at a slice thickness of 2.5 mm instead of 5 mm. Conclusions From this prospective study, we obtained 2 absolutely new findings that CMBs remained for as long as 9 years and a high-field or thin-slice MRI can detect concealed CMBs.

To quantify the effect of IV contrast, tube current and slice thickness on skeletal muscle cross-sectional area (CSA) and density (SMD) on routine CT. CSA and SMD were computed on 216 axial CT images obtained at the L3 level in 72 patients with variations in IV contrast, slice thickness and tube current. Intra-patient mean difference (MD), 95 % CI and limits of agreement were calculated using the Bland-Altman approach. Inter- and intra-analyst agreement was evaluated. IV contrast significantly increased CSA by 1.88 % (MD 2.33 cm2; 95 % CI 1.76–2.89) and SMD by 5.99 % (p

Injuries of the flexor–tendon–pulley system are common in rock climbers. The status of the A3 pulley ligament is crucial for grading such injuries. As standard MRI may miss lesions of the A3 pulley ligament, we introduce a semi-dynamic MRI sequence. Twenty-two fingers (14 volunteers, 3 injured climbers) were scanned using a sagittal T1 turbo spin echo sequence (repetition time: 400 ms, echo time: 14 ms, slice thickness: 5 mm) in six consecutive finger positions from stretched to maximum possible flexion. No pulley lesion was found in volunteers. Bowstringing was detected in 3 injured fingers including the A3 pulley. Semi-dynamic MRI is an technique that is easy to perform to identify injuries of the A3 pulley ligament that were not seen on standard imaging.

(1) Although guidelines about the use of MRI sequences for Multiple Sclerosis (MS) diagnosis and follow-up are available, variability in acquisition protocols is not uncommon in everyday clinical practice. The aim of this study was to evaluate the real-world application of MS imaging guidelines in different settings to clarify the level of adherence to these guidelines. (2) Via an on-line anonymous survey, neuroradiologists (NR) were asked about MRI protocols and parameters routinely acquired when MS patients are evaluated in their center, both at diagnosis and follow-up. Furthermore, data about report content and personal opinions about emerging neuroimaging markers were also retrieved. (3) A total of 46 participants were included, mostly working in a hospital or university hospital (80.4%) and with more than 10 years of experience (47.9%). We found a relatively good adherence to the suggested MRI protocols regarding the use of T2-weighted sequences, although almost 10% of the participants routinely acquired 2D sequences with a slice thickness superior to 3 mm. On the other hand, a wider degree of heterogeneity was found regarding gadolinium administration, almost routinely performed at follow-up examination (87.0% of cases) in contrast with the current guidelines, as well as a low use of a standardized reporting system (17.4% of cases). (4) Although the MS community is getting closer to a standardization of MRI protocols, there is still a relatively wide heterogeneity among NR, with particular reference to contrast administration, which must be overcome to guarantee an adequate quality of patients’ care in MS.

ZIEL: Weichteilgewebe ist die Substanz, die ein Skelett zur Mumie macht und Diagnosen über die Osteologie hinaus erlaubt. Entsprechend dem Ansatz des „structured reporting” in der klinischen Radiologie, wurde eine kürzlich entwickelte Checkliste für die Auswertung der Weichteilerhaltung von Ötzi in der Computertomografie (CT) verwendet. Das Ziel der Studie war, die „CT Checklist and Scoring System for the Assessment of Soft Tissue Preservation in Human Mummies“ bei Ötzi anzuwenden und Ötzis Weichteilerhaltung quantitativ mit den entsprechenden Scores anderer Mumien zu vergleichen. Verwendet wurde ein Ganzkörper-CT (SOMATOM Definition Flash, Siemens, Forchheim, Germany) bestehend aus fünf Scans, das im Januar 2013 in der Abteilung für Radiodiagnostik, Zentralkrankenhaus Bozen durchgeführt wurde (Schichtdicke 0,6 mm; Spannung von 80 bis 140 Kilovolt). Die standardisierte Auswertung erfolgte anhand der “CT Checklist and Scoring System for the Assessment of Soft Tissue Preservation in Human Mummies”. Aus der Hauptkategorie “A. Soft Tissues of Head and Musculoskeletal System” waren alle Checkpoints erhalten, aus der Hauptkategorie “B. Organs and Organ Systems” mehr als die Hälfte. Das Scoringsystem ergab einen Gesamtscore von 153 (von 200). Der Vergleich der Scores von Ötzi und drei Mumiensammlungen aus Vilnius, Litauen und Palermo, Sizilien sowie einer Einzelmumie aus Ägypten ergab überwiegend höhere Scores der Weichteilerhaltung bei Ötzi. Die Anwendung der Checkliste ermöglichte eine standardisierte Beurteilung und Dokumentation von Ötzis Weichteilerhaltung. Das Scoringsystem erlaubte einen quantitativen Vergleich zwischen Ötzi und anderen Mumien. Ötzi zeigte eine ausgezeichnete Weichteilerhaltung. · Der Ansatz des “structured reporting” kann auf die Paläoradiologie übertragen werden.. · Die Checkliste ermöglichte eine standardisierte Beurteilung und Dokumentation der Weichteilerhaltung.. · Das Scoringsystem ermöglichte einen quantitativen Vergleich zwischen Mumien.. · Ötzi hat eine ausgezeichnete Weichteilerhaltung im CT..

Pleural plaques (PPs) may be a risk factor for mortality from lung cancer in asbestos-exposed workers and are considered to be a marker of exposure. Diagnosing PPs is also important because asbestos-exposed patients should be offered a health surveillance that is mandatory in many countries. On the other hand PPs are useful for compensation purposes. In this study we aimed to evaluate the prevalence, as incidental findings, and the underreporting rate of PPs in chest CT scans (CTs) performed in a cohort of patients (1512) who underwent chest CT with a slice thickness no more than 1.25 mm. PPs were found in 76 out of 1482 patients (5.1%); in 13 out of 76 (17,1%) CTs were performed because of clinical suspicion of asbestos exposure and 5 of them (38%) were underreported by radiologist. In the remaining 63 cases (82.9%) there was no clinical suspicion of asbestos exposure at the time of CTs (incidental findings) and in 38 of these 63 patients (60.3%) PPs were underreported. Reaching a correct diagnosis of PPs requires a good knowledge of normal locoregional anatomy and rigorous technical approach in chest CT execution. However the job history of the patient should always be kept in mind.

Background: Extracranial stereotactic body radiation therapy is non-invasive alternative to other local treatment methods of patients with liver metastases. One of the main criteria for successful planning of the irradiation volume is a clear visualization of the contour of the tumor. MRI provides more valuable information about the boundaries of the tumor and critical structures, which makes its implementation mandatory when collecting anatomical and topographic data for the planning of stereotactic radiotherapy in patients with metastases in the liver. The use of different pulse sequences and the thickness of the slices affects the quality of visualization of the contour of the target, the fusion of CT and MRI data to select the irradiation volume. Objective: Improving the quality of anatomo-topographic data collection using the MRI for planning stereotactic radiation therapy in patients with liver metastases. Design and methods: Magnetom Siemens Avanto and Aera RT 1.5T. MRI protocol: overview T2 Cor and T2 Sag 5mm, T1ax VIBE DIXION 1.5mm, T2ax SPACE 2mm, DWI (ADC), T2ax TSE BLADE FS 3mm. With the help of this technique 15 patients with a total of 20 liver metastases was planned and executed stereotactic radiation therapy. Results: Used slice thickness and pulse sequences provide high spatial resolution, clear visualization of the contour of the tumor, the absence of technical difficulties with the fusion of CT and MRI tomograms at the station planning and the selection of the volume exposure. Conclusion: Optimization of the MRI protocol to collect anatomo-topographic data allowed to increase their informative value and diagnostic value for planning of SBRT in patients with liver metastases.

Accurate pancreas segmentation has application in surgical planning, assessment of diabetes, and detection and analysis of pancreatic tumors. Factors that affect pancreas segmentation accuracy have not been previously reported. The purpose of this study is to identify technical and clinical factors that adversely affect the accuracy of pancreas segmentation on CT.In this IRB and HIPAA compliant study, a deep convolutional neural network was used for pancreas segmentation in a publicly available archive of 82 portal-venous phase abdominal CT scans of 53 men and 29 women. The accuracies of the segmentations were evaluated by the Dice similarity coefficient (DSC). The DSC was then correlated with demographic and clinical data (age, gender, height, weight, body mass index), CT technical factors (image pixel size, slice thickness, presence or absence of oral contrast), and CT imaging findings (volume and attenuation of pancreas, visceral abdominal fat, and CT attenuation of the structures within a 5 mm neighborhood of the pancreas).The average DSC was 78% ± 8%. Factors that were statistically significantly correlated with DSC included body mass index (r = 0.34, p0.01), visceral abdominal fat (r = 0.51, p0.0001), volume of the pancreas (r = 0.41, p = 0.001), standard deviation of CT attenuation within the pancreas (r = 0.30, p = 0.01), and median and average CT attenuation in the immediate neighborhood of the pancreas (r = -0.53, p0.0001 and r = -0.52, p0.0001). There were no significant correlations between the DSC and the height, gender, or mean CT attenuation of the pancreas.Increased visceral abdominal fat and accumulation of fat within or around the pancreas are major factors associated with more accurate segmentation of the pancreas. Potential applications of our findings include assessment of pancreas segmentation difficulty of a particular scan or dataset and identification of methods that work better for more challenging pancreas segmentations.

BackgroundHeterogeneity in the infarct growth rate among anterior circulation large vessel occlusion (LVO) strokes has triage and treatment implications. Such data are lacking for basilar artery occlusion (BAO) strokes. We aim to describe the variability in brainstem infarct volume at presentation and compute the distribution of the infarct growth rate (IGR) and rate of loss of neurons during BAO strokes.MethodsA retrospective review of consecutive patients with BAO stroke with pretreatment MRI was performed. Ischemic core volume was manually calculated (product of slice thickness and sum of area of region of interests) for the brainstem lesion. The distribution of various brainstem infarct volume groups was analyzed and the IGR (including rate of loss of neurons) was computed.ResultsFifty-nine patients were included. Mean age was 64±13 and 34% were men. Mean National Institutes of Health Stroke Scale score was 20±11 and time to MRI was 9±5 hours. Mean brainstem ischemic core volume was 4.5±4.6 mL. According to predefined thresholds, 13% and 6% of patients with BAO stroke in the 0–6 hour time window were fast (5–10 mL) and ultra-fast progressors (>10 mL), respectively, and 14% of patients in the 6–24 hour time window were slow progressors (2.12 million.ConclusionApproximately 14% of BAO strokes are slow progressors and 19% are fast/ultra-fast progressors, with the rate of loss of neurons ranging from 2.1 million/min. Large heterogeneity exists in brainstem infarct volume at presentation and IGR among patients with BAO stroke.

INTRODUCTION: Programmable shunt valve settings can sometimes be difficult to assess using classic read-out tools, warranting a skull X-ray. RESEARCH QUESTION: Can we use available head computed tomography (CT) scans to determine the valve settings, in order to obviate the need for additional skull X-rays? MATERIAL AND METHODS: The valve setting of two different programmable shunts (Codman Certas Plus® and Sophysa Polaris®) were assessed by two blinded observers in 24 patients using 65 head CT scans (slice thickness ≤2 ​mm). Using multi-planar reconstruction (MPR) tools, images were resliced according to the direction of the valve, allowing a direct readout of the valve settings. We validated our CT based method against 32 available skull X-rays. RESULTS: For all CT scans it was possible to assess the valve setting. No interobserver variability was found and there was a 100 ​% concordance between the CT based method and skull X-rays. DISCUSSION: CT based assessment of programmable shunt valve settings is feasible and reliable. It may obviate the need for additional skull x-rays when a head CT scan is available. CONCLUSIONS: This technique can reduce radiation exposure and can be applied to historical CT imaging with unknown valve settings. ispartof: Brain Spine vol:1 pages:100003- ispartof: location:Netherlands status: Published online

// Wei Wang 1 , Jianbin Li 1 , Jun Xing 1 , Min Xu 1 , Qian Shao 1 , Tingyong Fan 1 , Bing Guo 1 , Shanshan Liu 1 1 Department of Radiation Oncology, Shandong Cancer Hospital affiliated to Shandong University, Shandong Academy of Medical Sciences, Jinan, Shandong province, China, 250117 Correspondence to: Jianbin Li, email: lijianbin@msn.com Keywords: breast-conserving treatment, tumor bed delineation, surgical clip number, CT slice thickness, cavity visualization score Received: March 09, 2016 Accepted: August 24, 2016 Published: September 15, 2016 ABSTRACT Objective: This study investigated interobserver and intraobserver variability in radiation oncologists’ definition of the tumor bed (TB) after breast-conserving surgery (BCS). Results: The TB volume, CVS and number of surgical clips were not significantly related to intraobserver variability. Moreover, no correlation was noted between CT slice thickness and interobserver variability (Δ inter , DSC inter ) in TB delineation, and no significant difference was noted among the three groups. The TB volume was negatively correlated with Δ inter . DSC inter improved significantly with increased TB volume and decreased Δ inter . DSC inter also increased significantly in patients with a CVS of 3 to 5 compared with patients with a CVS of 1 to 2. DSC inter was thus positively correlated with the CVS, with a correlation coefficient of 0.451. The use of 7 to 9 surgical clips neither decreased Δ inter nor increased DSC inter. Materials and Methods: Five or more surgical clips were placed at the TB during lumpectomy. The TB was delineated on the end expiration scan. The data were stratified based on the cavity visualization score (CVS), CT slice thickness and surgical clip number. The Dice similarity coefficient (DSC) and inter(intra)observer variability (Δ inter and Δ intra ) in different groups were evaluated and compared. Conclusions: Inter(intra)observer variability in TB delineation was decreased for breast cancer patients implanted with 5 or more surgical clips in the cohort with a higher CVS and a larger TB. The use of more than 6 surgical clips did not significantly improve TB delineation, so 5 to 6 surgical clips are likely adequate to delineate the TB.

BACKGROUND Intracerebral hemorrhage (ICH) volumes are frequently used for prognostication and inclusion of patients in clinical trials. We sought to compare the original ABC/2 method and sABC/2, a simplified version with the planimetric method. METHODS We retrospectively reviewed admission head CT scans of consecutive ICH patients admitted to a single academic center from July 2012 to April 2013. We assessed ICH volume on the admission. In ABC/2 method, A = greatest hemorrhage diameter by CT, B = diameter perpendicular to A, C = the approximate number of CT slices with hemorrhage multiplied by the slice thickness. C is weighted by area as 75%. However, in the sABC/2 method, C is the total number of cuts with ICH without any weighting. Bland–Altman plots were generated for both the ABC/2 and sABC/2 methods in comparison to the planimetric method. RESULTS One hundred thirty-five patients with spontaneous ICH were included in the final analysis. Bland–Altman analysis illustrated that both ABC/2 and sABC/2 were concordant with the planimetric method. ABC/2 had more bias than sABC/2 (47% vs. 5%, respectively) with no evidence of a linear trend. For differentiating a volume threshold of 30 mL, ABC/2 was less sensitive but more specific than sABC/2 (P < .0001). Concordance between planimetry, ABC/2, and sABC/2 was high, evidenced by most coefficients exceeding .90. CONCLUSION Simplified ABC/2 (sABC/2) method performs better than ABC/2 in calculating ICH volumes. Moreover, it is better in differentiating a volume threshold of 30 mL. These findings may have implications for outcomes prediction and clinical trials inclusion.

The purpose of this study is to assess the performance of routinely used MRI sequences with and without contrast enhancement in the diagnostic evaluation of dural venous sinus thrombosis (DVST).We identified consecutive patients older than 18 years who underwent concurrent standardized brain MRI and contrast-enhanced (CE) MR venography (MRV) examinations for suspected DVST. The seven MRI sequences that were used (axial unenhanced T1-weighted, T1-weighted CE, T2-weighted, DWI, T2-weighted FLAIR, T2-weighted gradient-recalled echo [GRE], and sagittal 3D T1-weighted GRE CE sequences) were randomized, anonymized, and reviewed independently by two neuroradiologists who were blinded to the final diagnosis. Ten separate venous sinus segments were evaluated. CE MRV was the reference standard for determining the presence or absence of DVST, and it was performed using the following imaging parameters: TR/TE, 4.1-77/1.4-9.5; flip angle, 12-35°; and slice thickness, 0.8-1.4 mm. The diagnostic performance of and interobserver variability for each sequence was assessed per patient and per segment.Thirty-six patients with DVST (72% of whom had acute thrombosis and 28% of whom had chronic thrombosis) and 29 patients without DVST were included in the study. For each sequence, the AUC values for the detection of DVST per patient, as determined by reviewer 1 and reviewer 2, respectively, were as follows: for T1-weighted unenhanced sequences, 55% and 61%; for T1-weighted CE sequences, 79% and 80%; for T2-weighted sequences, 77% and 76%; for DWI sequences, 59% and 64%; for T2-weighted FLAIR sequences, 70% and 72%; for T2-weighted GRE sequences, 64% and 66%; and for the 3D T1-weighted GRE CE sequence, 77% and 81%. The diagnostic performance of the 3D T1-weighted GRE CE sequences was statistically significantly greater than that of the other sequences. Interobserver variability ranged from 0.26 (for T1-weighted unenhanced sequences) to 0.73 (for the DWI sequence). Overall, for each reviewer and with the use of all evaluated sequences, MRI had a high sensitivity (99% for both reviewers) but low specificity (14% for reviewer 1 and 48% for reviewer 2) for the detection of DVST.Sequences used in routine brain MRI performed with and without contrast enhancement have varying strengths that are important to recognize when the likelihood of DVST is assessed, but they do not replace the utility of dedicated CE MRV.

Purpose To determine the optimal slice thickness, playback rate, and scan time for uterine peristalsis with 3.0T magnetic resonance imaging (MRI). Materials and Methods In all, 23 young female volunteers underwent a 3.0T MRI scan with different slice thicknesses of 3 mm (Cine3mm), 5 mm (Cine5mm), and 7 mm (Cine7mm) for 6 minutes. Subjective image quality score, signal-to-noise ratios (SNRs), and contrast-to-noise ratios (CNRs) of those MR images were evaluated by two radiologists independently. The number, intensity, and direction of uterine peristalsis with different thickness were compared at various playback rates. Also, the peristalsis frequency was counted and compared in different acquisition durations (1–6 minutes). Results The subjective image quality score, peristalsis number, and intensity were significantly higher in Cine7mm and Cine5mm than Cine3mm (P < 0.05), while the SNRs and CNRs of Cine7mm were significantly higher than Cine3mm (P < 0.05). Peristalsis numbers did not differ significantly at different playback rates with the same slice thickness (P = 0.548–0.962). However, peristalsis intensity at 12×, and 15× was significantly greater than that at 8× the actual speed for Cine7mm and Cine5mm (P < 0.05). The peristalsis frequency at 3, 4, 5, 6 minutes was significantly higher than that at 1 minute and 2 minutes (P < 0.05). Conclusion We recommend a slice thickness of 5 mm or 7 mm and a scan time of 3 minutes for uterine peristalsis with 3.0T MRI, and a playback rate of 12× or 15× the actual speed for peristalsis observation. J. Magn. Reson. Imaging 2016;44:1397–1404.

Mandibular fractures are frequently encountered in the trauma setting and comprise a significant number of facial injuries. The purpose of this study was to evaluate the prevalence and injury patterns of unifocal and multifocal mandibular fractures using thin-section imaging. Following IRB approval, 220 patients with mandibular fractures identified on maxillofacial CT scans performed between October 2008 and February 2011 were retrospectively reviewed. Examinations were performed on 64-multidetector row CT scanners with axial images acquired at 1.25-mm slice thickness. The location and number of fractures as well as causative mechanisms were recorded. Fractures were unifocal in 108/220 (49 %) and multifocal in 112/220 (51 %) patients. The mandibular angle was the most common fracture site in both unifocal and multifocal mandible fractures. In cases with multifocal mandibular fractures, bilateral fractures were more common (83 %) than unilateral multifocal mandibular fractures (17 %). Fractures involving the parasymphysis, the mandibular body, or ramus were significantly associated with the presence of additional mandibular fractures (p < 0.0001). While multifocal and unifocal fractures occurred in near equal frequency, bilateral multifocal fractures were much more common than unilateral multifocal mandibular fractures. Alveolar ridge fractures were exclusively seen in unifocal mandibular fractures.

Background: The advent of new magnetic resonance imaging (MRI) techniques has improved acute stroke diagnosis. Susceptibility weighted imaging (SWI) has an important role in the management of cerebro-vascular strokes. Patients and Method: The study was conducted upon 50 patients clinically diagnosed with cerebro-vascular strokes and referred to department of radio-diagnosis, Faculty of Medicine, Minia University. Computed tomography (CT) was done at first then magnetic resonance imaging was performed on a 1.5T Philips MR system using conventional MRI sequences as fluid attenuated inversion recovery (FLAIR), T2-weighted, T1-weighted and advanced sequences as susceptibility-weighted imaging (SWI) with the parameters including slice thickness, voxel size, field of view (FOV) and matrix,. They were done after the approval of ethical committee of our institution. Informed written consents were taken from the patients or their relatives. Results : In our study, we found that 35 patients presented with acute non hemorrhagic infarction even on SWI and 15 patients presented with hemorrhagic infarction noted in SWI. Only ten of those patients with hemorrhagic infarction detected in CT. We found that detection rate of hemorrhage in SWI sequence was (100%). Detection rate of hemorrhage in CT was (33.3%). In SWI as regarding detection of different signs of acute ischemic strokes we found that of hemorrhage was (88%), detection rate of prominent cortical veins in vicinity of infarct was (62%) and detection rate of dark vessel sign was 6%. Comparative studies between them were done revealed that hemorrhage was the most important sign detected at SWI. Conclusion : From this study we concluded that new imaging SWI MRI modality is a valuable MRI sequence in imaging hemorrhagic transformation in ischemic stroke.

Background: multiple sclerosis (MS) is a chronic inflammatory disease that affects the central nervous system (CNS). Its diagnosis is characterized by foci of demyelination, disseminated over time and anatomical space, both clinically and radiologically. Consensus guidelines for the diagnosis of MS have been established to identify the proper sequences and imaging technique. Objective: this study aims to investigate the adherence of Taif hospitals to these consensus guidelines. Method: data were collected from the radiology departments of 3 main hospitals in Taif (King Abdul-Aziz Specialist Hospital, King Faisal Medical Complex, and Al-Hada Hospital for Armed Forces). The standard magnetic resonance imaging (MRI) protocol for MS in each hospital was reviewed using the picture archiving and communication system (PACS). The comparisons were based on the strength of the magnetic field, slice thickness, slice orientation, coverage, and the MR core sequences used. Results: each Taif hospital has its own protocol, which differ from consensus guidelines. The main difference is the hospitals’ lack of 3D sequences. Another difference is the lack of inversion recovery prepared T1 sequences. Finally, for follow-up patients, no contrast administration exists in Taif hospitals. Conclusion: this study shows some major differences in the MS protocols among Taif hospitals. This is probably due to poor awareness of the guidelines in the radiology community. Neuroradiologists at Taif hospitals should ensure the recommended protocol is followed.

To compare thick (5 mm) and thin slice images (1.5 mm) of lung, soft tissue, and bone window in thoracoabdominal trauma computed tomography.167 Patients that underwent thoracoabdominal trauma CT between November 2014 and December 2015 were included in the study. CT data were reconstructed in a transverse direction with 5 mm and 1.5 mm slice images of lung, soft tissue, and bone window. Two blinded raters (radiologists) evaluated the collected data by detecting predefined injuries in different organ areas. Reconstruction and evaluation times as well as detected injuries were noted and compared.Reconstruction and evaluation times were significantly higher with 1.5 mm thin-slice images, and the effect strength according to Rosenthal displayed a strong effect of 0.61 ( 0.1 small effect, 0.3 middle effect, and 0.5 strong effect). Average evaluation time differences were 62.7 s (33.9 s-91.5 s) in bone window between 1.5 mm and 3 mm for rater 1 (p 0.001) and 71.4 s (43.1 s-99.7 s) for rater 2 (p 0.001). Average time differences between 1.5 mm and 5 mm were 68,7 s (43.9 s-93.5 s) for rater 1 and 75.3 s (44.7 s-105.9 s) for rater 2 in lung window (p 0.001) and 66.6 s (28.8 s-104.4 s) for rater 1 and 114 s (74.4 s-153.6 s) for rater 2 in soft-tissue window (p 0.001). There was no significant difference regarding soft-tissue and lung injuries, except non-significant improvement in the detection of bone fractures.Thin-slice images do not bring any significant benefit in thoracoabdominal trauma CT of soft-tissue and lung injuries, but they can be helpful for the diagnosis of bone fractures and incidental findings.

MRI is an excellent diagnostic tool in the imaging of sports-related musculoskeletal pathology; however, standard slice thickness acquisitions can lack the spatial resolution to accurately define and characterise osseous abnormalities. Standard MRI sequences may be supplemented with CT to reduce diagnostic uncertainty. We provide a clinical perspective, in the form of pictorial review, on the potential applications of 3D MRI sequences, specifically using volumetric interpolated breath-hold examination in the characterisation of various musculoskeletal osseous pathologies. The potential to negate the requirement for CT in a young radiation sensitive cohort is a clinically significant concept and suggests the requirement for further studies comparing the performance of volumetric MRI to CT.

Contains fulltext : 195164.pdf (Publisher’s version ) (Open Access) Objective: Imaging studies in diffuse low-grade gliomas (DLGG) vary across centers. In order to establish a minimal core of imaging necessary for further investigations and clinical trials in the field of DLGG, we aimed to establish the status quo within specialized European centers. Methods: An online survey composed of 46 items was sent out to members of the European Low-Grade Glioma Network, the European Association of Neurosurgical Societies, the German Society of Neurosurgery and the Austrian Society of Neurosurgery. Results: A total of 128 fully completed surveys were received and analyzed. Most centers (n = 96, 75%) were academic and half of the centers (n = 64, 50%) adhered to a dedicated treatment program for DLGG. There were national differences regarding the sequences enclosed in MRI imaging and use of PET, however most included T1 (without and with contrast, 100%), T2 (100%) and TIRM or FLAIR (20, 98%). DWI is performed by 80% of centers and 61% of centers regularly performed PWI. Conclusion: A minimal core of imaging composed of T1 (w/wo contrast), T2, TIRM/FLAIR, PWI and DWI could be identified. All morphologic images should be obtained in a slice thickness of

Rationale and Objectives Coronary artery calcium (CAC) images can be reconstructed with thinner slice thickness on some modern multidetector-row computed tomography scanners without additional radiation. We hypothesized that the isotropic 0.5-mm CAC reconstruction outperforms the conventional 3.0-mm reconstruction in detecting and quantifying coronary calcium, and we proposed to compare them by validating against spatially registered intravascular ultrasound with radiofrequency backscatter-virtual histology (IVUS-VH). Materials and Methods Twenty-seven patients were enrolled, and 5976 mm of coronary arteries were analyzed. A semiautomatic software was developed to coregister CAC and IVUS-VH on a detailed slice-by-slice basis. Calcium detection and calcium volume quantification were evaluated and compared using varying calcium attenuation thresholds. Algorithms for deriving individualized optimal threshold and comparable Agatston score on the 0.5-mm reconstruction were developed. Results The isotropic 0.5-mm reconstruction achieved significantly higher area under receiver-operating curve than the conventional 3.0-mm reconstruction (0.9 vs. 0.74, P P Conclusions By optimizing the calcium threshold, the 0.5-mm reconstruction is superior to the conventional 3.0-mm in detecting and quantifying calcium, which may improve the clinical value of CAC without additional radiation.

The hyoid bone anchors and supports the vocal tract. Its complex shape is best studied in three dimensions, but it is difficult to capture on computed tomography (CT) images and three-dimensional volume renderings. The goal of this study was to determine the optimal CT scanning and rendering parameters to accurately measure the growth and developmental anatomy of the hyoid and to determine whether it is feasible and necessary to use these parameters in the measurement of hyoids from in vivo CT scans. Direct linear and volumetric measurements of skeletonized hyoid bone specimens were compared with corresponding CT images to determine the most accurate scanning parameters and three-dimensional rendering techniques. A pilot study was undertaken using in vivo scans from a retrospective CT database to determine feasibility of quantifying hyoid growth. Scanning parameters and rendering technique affected accuracy of measurements. Most linear CT measurements were within 10% of direct measurements; however, volume was overestimated when CT scans were acquired with a slice thickness greater than 1.25 mm. Slice-by-slice thresholding of hyoid images decreased volume overestimation. The pilot study revealed that the linear measurements tested correlate with age. A fine-tuned rendering approach applied to small slice thickness CT scans produces the most accurate measurements of hyoid bones. However, linear measurements can be accurately assessed from in vivo CT scans at a larger slice thickness. Such findings imply that investigation into the growth and development of the hyoid bone, and the vocal tract as a whole, can now be performed using these techniques.

The purpose of this study was to assess the effect of model-based iterative reconstruction (MBIR) on CT number measurements within small (10-29 mm) low-attenuation renal masses.One hundred 10- to 29-mm exophytic or endophytic low-attenuation renal lesions imaged with CT (unenhanced and nephrographic [100 seconds] phases, 120 kVp, variable mA, 2.5-mm slice thickness) were identified in 100 patients. The raw CT source data were prospectively reconstructed twice: once using Veo MBIR and once using a blend of 30% adaptive statistical iterative reconstruction (ASiR) and filtered back projection (FBP). Lesions were chosen to form four equal-sized (n = 25) groups stratified by lesion size (10-19 or 20-29 mm) and growth pattern (endophytic or exophytic). Attenuation (in HU) was measured using identical ROIs and compared with two-tailed t tests. The effects of patient diameter and lesion anatomy on attenuation discrepancies of 5 HU or more were assessed using binary logistic regression.Mean MBIR attenuation was not significantly different than mean 30% ASiR/FBP attenuation in the overall study population (unenhanced phase, 17 ± 13 vs 17 ± 13 HU, p = 0.74; nephrographic phase, 31 ± 27 vs 30 ± 26 HU, p = 0.89) or in any subgroup (p = 0.63-0.95). Only lesion size predicted discrepancies of 5 HU or more (p = 0.008; odds ratio, 1.20 [95% CI, 1.05-1.34] per 1 mm decrease) (p = 0.19-0.98 for the other variables). Seven lesions had enhancement of 20 HU or more with only one reconstruction method (MBIR = 4; 30% ASiR = 3).Veo MBIR has no significant or consistent effect on attenuation measurements within small (10-29 mm) low-attenuation renal masses and is therefore unlikely to change clinically accepted attenuation thresholds for renal mass characterization.

Coronary artery calcium (CAC) scanning is a reliable, noninvasive technique for estimating overall coronary plaque burden and for identifying risk for future cardiac events. Arthur Agatston and Warren Janowitz published the first technique for scoring CAC scans in 1990. Given the lack of available data correlating CAC with burden of coronary atherosclerosis at that time, their scoring algorithm was remarkable, but somewhat arbitrary. Since then, a few other scoring techniques have been proposed for the measurement of CAC including the Volume score and Mass score. Yet despite new data, little in this field has changed in the last 15 years. The main focus of our paper is to review the implications of the current approach to scoring CAC scans in terms of correlation with the central disease - coronary atherosclerosis. We first discuss the methodology of each available scoring system, describing how each of these scores make important indirect assumptions in the way they account (or do not account) for calcium density, location of calcium, spatial distribution of calcium, and microcalcification/emerging calcium that might limit their predictive power. These assumptions require further study in well-designed, large event-driven studies. In general, all of these scores are adequate and are highly correlated with each other. Despite its age, the Agatston score remains the most extensively studied and widely accepted technique in both the clinical and research settings. After discussing CAC scoring in the era of contrast enhanced coronary CT angiography, we discuss suggested potential modifications to current CAC scanning protocols with respect to tube voltage, tube current, and slice thickness which may further improve the value of CAC scoring. We close with a focused discussion of the most important future directions in the field of CAC scoring.

The aim of this study was to investigate the organ doses of patients undergoing computed tomography (CT) examination using the wide bore General Electric (GE) “Light Speed RT” unit. The head, chest and pelvic regions of the Rando-phantom were scanned with 120 kV, 200 mA, and 2.5 mm slice thickness for helical and axial modes. Thermoluminescent Dosimeter (TLD) pairs were used for the dosimetry of 10 organs. TL-counts were converted to dose by using CTDIcenter dose on CT-phantom. For the calculation of the organ doses, the ImPACT software was utilized by entering CTDIair (100 mAs) in small and large field of view (26.43 and 21.17 mGy respectively). The in-field dose ranges in helical and axial modes were 64.3 - 38 mGy and 47.6 - 19.7 mGy in head, 48.3 - 14.1 mGy and 34.1 - 10 mGy in chest, 28.4 - 10.2 mGy and 21 - 8.5 mGy in pelvic, respectively. The organ doses from software and TLD were compared and tailored as the in-field and the out-field radiation. First results showed that the organ dose was relatively higher in the helical mode on both direct and indirect measurement. The in-field organ dose differences between TLD and software were seen. In helical and axial modes, the dose differences ranged from +1 to +13.3 and -8.3 to +9.6 mGy for head exam, +1.1 to +15.3 and +0.3 to +9.1 mGy for chest, and -21.7 to +1.9 and -15.5 to +1.8 mGy for pelvic. The availability of this program for organ dose calculations by measuring CTDIair value for CT device used in the radiotherapy would be considered valuable.

Introduction. Despite the use of multiple diagnostic imaging techniques, a non-invasive differential diagnosis of focal lesions in the liver is still a challenging task. It is even more significant, considering the risk of complications related to liver biopsy. On the other hand, the availability of non-invasive radiological and diagnostic imaging methods has resulted in the increased detectability of incidental hepatic lesions. Therefore, further investigation of newer and more effective methods of differentiating benign from malignant hepatic lesions is extremely useful. The aim of the study was to assess the diagnostic value of Diffusion-Weighted Magnetic Resonance Imaging (DW MRI) in differentiating benign from malignant focal lesions in the liver. Material and methods. Fifty one patients with hepatic lesions detected by magnetic resonance (MR) examination were enrolled in the study. Each lesion was then verified histopathologically, cytologically, or by observation. Ninety five (71 malignant and 24 benign) hepatic focal lesions were analysed. Apart from a standard MR liver examination, an echo planar imaging spin echo diffusion weighted sequence was performed, with a slice thickness of 5 or 6 mm. The maximal b-value was 1000 s/mm 2 and the minimal 0 s/mm 2 .In the study, the following were assessed: the presence of restricted diffusion, an absolute ADC (apparent diffusion coefficient) value, the decrease of signal intensity in DW MRI with an increase in the b-value. Results. Confirming or ruling out the restricted diffusion is usually the first effective step in differentiating benign from malignant hepatic lesions, as indicated in the study results. In the material analysed, the diffusion restriction occurred statistically significantly more frequently in malignant (87.3 %) compared to benign lesions (12.5%), (p 1.04 × 10 -3 mm2/s to be benign and lesions with ADC value ≤ 1.04 × 10 -3 mm 2 /s to be malignant, 75.8% lesions were correctly classified. Conclusions. The results obtained indicate that restricted diffusion, as a marker for malignant lesions, has the highest value in DW MRI in differentiating benign from malignant lesions in the liver.

The objective of this study is to evaluate measurement variability in volumetric assessment of pulmonary nodules on low-dose CT images with a view toward determining how this variability is influenced by nodule size.A large CT screening database was reviewed to identify solid pulmonary nodules that had remained stable in size on the basis of findings from at least three scans obtained over a 2-year period. Two software packages (Lung VCAR and syngo.via) were used to assess the nodule volume on the two most recent CT scans, which were obtained at a slice thickness of 0.625 mm. The percentage of volume change was calculated for each nodule. The SD of the percentage of volume change was determined for nodules in each of the following nodule diameter size categories: less than 4 mm, 4-5 mm, 6-9 mm, and 10 mm or larger. The diameter was the mean of the length and width in the CT image that represented the largest cross-sectional area of the nodule.The 171 stable nodules that were identified in 117 CT screening participants (median age, 61 years) ranged in size from 2.2 to 18.7 mm. The time between acquisition of the first and last CT images ranged from 3.7 to 17.8 years (median, 11.5 years). For each of the four categories of diameter size (4, 4-5, 6-9, and ≥ 10 mm), the SD of the percentage of volume change was 20.4%, 17.7%, 14.6%, and 3.7%, with the use of Lung VCAR, and 59.5%, 24.3%, 9.1%, and 6.2%, with the use of syngo.via, respectively. The SD decreased with increasing nodule diameter, with the use of both software packages.Measurement variability decreased with increasing nodule diameter for both software packages and was different between the two software packages.

For pediatric oncology patients, CT scans are performed to assess treatment response and disease progression. CAD may be used to detect lung nodules which would reflect metastatic disease. The purpose of this study was to investigate the effects of reducing radiation dose and varying slice thickness on CAD performance in the detection of solid lung nodules in pediatric patients. The dataset consisted of CT scans of 58 pediatric chest cases, from which 7 cases had lung nodules detected by radiologist, and a total of 28 nodules were marked. For each case, the original raw data (sinogram data) was collected and a noise addition model was used to simulate reduced-dose scans of 50%, 25% and 10% of the original dose. In addition, the original and reduced-dose raw data were reconstructed at slice thicknesses of 1.5 and 3 mm using a medium sharp (B45) kernel; the result was eight datasets (4 dose levels x 2 thicknesses) for each case An in-house CAD tool was applied on all reconstructed scans, and results were compared with the radiologist’s markings. Patient level mean sensitivities at 3mm thickness were 24%, 26%, 25%, 27%, and at 1.5 mm thickness were 23%, 29%, 35%, 36% for 10%, 25%, 50%, and 100% dose level, respectively. Mean FP numbers were 1.5, 0.9, 0.8, 0.7 at 3 mm and 11.4, 3.5, 2.8, 2.8 at 1.5 mm thickness for 10%, 25%, 50%, and 100% dose level respectively. CAD sensitivity did not change with dose level for 3mm thickness, but did change with dose for 1.5 mm. False Positives increased at low dose levels where noise values were high.

Purpose: To evaluate a new approach for predicting nodule volume measurement bias and variability when scanning with a specific CT scanner and acquisition protocol. Methods: A GE LightSpeed VCT scanner was used to scan 3 new rolls of 3M 3/4 x 1000 Inch Scotch Magic tape with a routine chest protocol (120 kVp, 100 mA, 0.4 s rotation, .98 pitch, STANDARD kernel) at three different slice thicknesses and spacings. Each tape scan was independently analyzed by fully automated image quality assessment software, producing fundamental image quality characteristics and simulated lung nodule volume measurements for a range of sphere diameters. The same VCT scanner and protocol was then used to obtain 10 repeat CT scans of an anthropomorphic chest phantom containing multiple Teflon spheres embedded in foam (diameters = 4.76mm, 6.25mm, and 7.94mm). The observed volume of the spheres in the 30 (3 reconstructions per scan) repeat scans was provided by independently developed nodule measurement software. Results: The predicted vs observed mean volume (mm3 ) and CV for 3 slice thicknesses and sphere sizes was obtained. For 0.625mm slice thickness scans the predicted vs observed values were (44.3,0.91)-vs-(48.2,1.17), (110.4,0.51)-vs-(124.1,0.47), and (219.9,0.29)-vs-(250.1,0.34), for 4.76mm, 6.25mm, and 7.94mm spheres respectively. For 1.25mm slice thickness the corresponding values were (42.1,0.98)-vs-(47.6,1.35), (106.9,0.56)-vs-(123.1,0.61), and (214.8,0.32)-vs-(248.8,0.41). For 2.5mm slice thickness the corresponding values were (23.9,9.53)-vs-(36.8,12.50), (77.6,3.84)-vs-(110.5,3.20), and (173.0,1.57)-vs-(233.9,1.32). Conclusion: Volume measurement bias and variability for lung nodules based on nodule size and acquisition protocol can potentially be predicted using a new method that utilizes fundamental image characteristics and simulation.

Background: Objective: The aim of this study is to evaluate the effect of slice thickness on the visibility of inferior alveolar canal (IAC) in cone‑beam computed tomography (CBCT) images. Materials and Methods: CBCT images of thirty patients (15 male and 15 female) with an age range between 40–50 years old were used. Cross‑sectional images were obtained with 0.5, 1, and 2 mm slice thickness and 2 mm interval. Two oral radiologists with at least 5 years’ of experience observed all of the 90 images and rated the images based on the visibility of IAC in a 4‑score classification (highly visible, visible, nearly visible, nearly invisible). Friedman test was used for the comparison of visibility of IAC in different slice thicknesses. To do the above test, the average of the scores of two examiners was calculated. A P. value below 0.05 was considered significant. Results: Visibility of IAC in different slice thicknesses of both raters showed no significant difference (P = 0.20). Conclusion: Within the limitations of this study the slice thickness has no effect on visibility of IAC in cross‑sectional images. Future studies on other multiplanar images are recommended Key Words: Cone beam computed tomography, cross,section, inferior alveolar nerve

[Background] It is expected that thrombus density and perviousness measurements are dependent on CT slice thickness, because density values are blurred in thicker slices. This study quantifies the effect of slice thickness on thrombus density and perviousness measurements. [Methods] Thrombus density and perviousness measurements were performed in 50 patients for varying slice thicknesses, using a manual and semi-automated technique. Linear regression was performed to determine the dependence of density measurements on slice thickness. Paired t-tests were used to test for differences in density and perviousness measures for varying slice thickness. [Results] Thrombus density decreased for increasing slice thickness with approximately 2HU per mm. Perviousness measurements were significantly higher for thick slice compared to thin slice NCCT. [Conclusion] Thick slice NCCT scans result in an underestimation of thrombus density and overestimation of thrombus perviousness.

OBJECTIVES: To validate aortic valve calcium (AVC) load measurements by multidetector row computed tomography (MDCT), to evaluate the impact of tube potential and slice thickness on AVC scores, to examine the accuracy of AVC load in distinguishing severe from nonsevere aortic stenosis (AS) and to investigate its effectiveness as an alternative diagnosis method when echocardiography remains inconclusive. METHODS: We prospectively studied 266 consecutive patients with moderate to severe AS who underwent MDCT to measure AVC load and a comprehensive echocardiographic examination to assess AS severity. AVC load was validated against valve weight in 57 patients undergoing aortic valve replacement. The dependence of AVC scores on tube potential and slice thickness was also tested, as well as the relationship between AVC load and echocardiographic criteria of AS severity. RESULTS: MDCT Agatston score correlated well with valve weight (r = 0.82, p < 0.001) and hemodynamic indices of AS severity (all p < 0.001). Ex-vivo Agatston scores decreased significantly with increasing tube potential and slice thickness (repeated measures ANOVA p < 0.001). Multivariate analysis identified mean gradient, the indexed effective orifice area, male gender and left ventricular outflow tract cross-sectional area as independent correlates of the in-vivo AVC load. CONCLUSIONS: MDCT-derived AVC load correlated well with valve weight and hemodynamic indices of AS severity. It also depends on tube potential and slice thickness, thus suggesting that these parameters should be standardized to optimize reproducibility and accuracy.

Contains fulltext : 178221.pdf (Publisher’s version ) (Closed access) OBJECTIVE: Ultrafast dynamic contrast-enhanced magnetic resonance imaging of the breast enables assessment of the contrast inflow dynamics while providing images with diagnostic spatial resolution. However, the slice thickness of common ultrafast techniques still prevents multiplanar reconstruction. In addition, some temporal blurring of the enhancement characteristics occurs in case view-sharing is used. We evaluate a prototype compressed-sensing volume-interpolated breath-hold examination (CS-VIBE) sequence for ultrafast breast MRI that improves through plane spatial resolution and avoids temporal blurring while maintaining an ultrafast temporal resolution (less than 5 seconds per volume). Image quality (IQ) of the new sequence is compared with an ultrafast view-sharing sequence (time-resolved angiography with interleaved stochastic trajectories [TWIST]), and assessment of lesion morphology is compared with a regular T1-weighted 3D Dixon sequence (VIBE-DIXON) with an acquisition time of 91 seconds. MATERIALS AND METHODS: From April 2016 to October 2016, 30 women were scanned with the CS-VIBE sequence, replacing the routine ultrafast TWIST sequence in a hybrid breast MRI protocol. The need for informed consent was waived. All MRI scans were performed on a 3T MAGNETOM Skyra system (Siemens Healthcare, Erlangen, Germany) using a 16-channel bilateral breast coil. Two reader studies were conducted involving 5 readers. In the first study, overall IQ of CS-VIBE and TWIST in the axial plane was independently rated for 23 women for whom prior MRI examinations with TWIST were available. In addition, the presence of several types of artifacts was rated on a 5-point scale. The second study was conducted in women (n = 16) with lesions. In total, characteristics of 31 lesions (5 malignant and 26 benign) were described independently for CS-VIBE and VIBE-DIXON, according to the BI-RADS MRI-lexicon. In addition, a lesion conspicuity score was given. RESULTS: Using CS-VIBE, a much higher through-plane spatial resolution was achieved in the same acquisition time as with TWIST, without affecting in-plane IQ (P = 0.260). Time-resolved angiography with interleaved stochastic trajectories showed slightly more motion artifacts and infolding and ghosting artifacts compared with CS-VIBE, whereas CS-VIBE showed more breathing and pulsation artifacts. For morphologic assessment, intrareader agreement between CS-VIBE and the more time-consuming VIBE-DIXON was slight to almost perfect, and generally higher than interreader agreement. Mean sensitivity (84.0% and 92.0% for CS-VIBE and VIBE-DIXON, P = 0.500) and specificity (60.0% and 55.4% for CS-VIBE and VIBE-DIXON, P = 0.327) were comparable for both sequences. CONCLUSIONS: Compressed-sensing volume-interpolated breath-hold examination allows an increase of the through-plane spatial resolution of ultrafast dynamic contrast-enhanced magnetic resonance imaging compared with TWIST at a comparable in-plane IQ. Morphological assessment of lesions using CS-VIBE is comparable to VIBE-DIXON, which takes 18 times longer. Consequently, CS-VIBE enables 3D evaluation of breast lesions in ultrafast breast MRI.

Introduction The purpose of the current study was to investigate the effects of residual articular incongruity after Bennett's fracture on load distribution of the joint surface. Our aim was to investigate whether a residual joint step and the altered load distribution led to negative clinical outcomes or symptomatic degenerative osteoarthritis of the trapeziometacarpal joint. Patients and methods Twenty-four patients were available for long-term follow-up examination and were contacted by phone, and they returned for follow-up examination. Computed tomography (CT) scans of both carpometacarpal (CMC) joints were performed. CT scans were taken in the sagittal plane of the forearms with a slice thickness of 0.625 mm for three-dimensional reconstruction. The CMC joints were analysed due to a residual step in the joint. Only patients with a residual step-off were included in this study. To determine the areas of maximum density in the joint, CT-osteoabsorptiometry was performed. Results Ten patients had the maximum loading area radial and two patients central. The second major position of mineralization was detected central in four patients, volar–ulnar in two patients, radial in one patient, dorso-radial in one patient, volar in one patient and volar–radial in two patients. Conclusion Finally, no higher loading in the area of the beak fragment could be found. The Wagner technique, even if it results in a persistent 1–2-mm intra-articular step-off of the beak fragment, is still the favourable method for the treatment of Bennett's luxation fractures.

Introduction The aim of this study was to compare the diagnostic performances of multi-detector computed tomography (MDCT) reconstruction at two different slice thicknesses (1 mm, ‘high resolution’ vs. 5 mm, ‘routine’) with respect to the detection of blebs and bullae (BBs) in patients with primary spontaneous pneumothorax (PSP). Methods Thirty-one patients underwent wedge resection of BBs (29 unilateral and 2 bilateral) for PSP from January 2010 to January 2013. Two observers assessed the presence and locations of BBs independently using high-resolution CT (HRCT) and routine CT reconstruction, and compared the sensitivities of each reconstruction method for BB detection using operative findings as a standard reference. In addition, the number of BBs in each CT image set was recorded and inter-observer agreements were evaluated. Results Sensitivity for the detection of BBs was significantly better for HRCT than routine CT (97.0% vs. 63.6% for observer 1 and 94.0% vs. 57.6% for observer 2, respectively, both P-values

We evaluated a dual energy, split bolus computerized tomography protocol that provides virtual noncontrast, parenchymal and urographic phases in a single scan. We assessed the sensitivity of the virtual noncontrast phase using this protocol to detect urinary stones compared to the gold standard of the true noncontrast phase.We prospectively enrolled in the study 81 patients who underwent unenhanced single energy computerized tomography at 120 kV/200 mA as well as contrast enhanced dual energy computerized tomography on a Somatom® Definition Flash-CT (tube A 80 kV/233 mA and tube B SN 140 kV/180 mA with 1/0.8 mm slice thickness). For the split bolus protocol 400 mg/ml Iomeron® were injected at 2 time points, that is 15 ml 10 minutes before the scan and 80 ml 65 seconds before the scan. In a consensus reading 2 readers evaluated the presence and diameter of stones on the true and virtual noncontrast phases.Of the 350 stones noted on the true noncontrast phase we found 289 on the virtual noncontrast phase as well as 13 false-positive and 66 false-negative stones. Sensitivity was 98.4%, 89.8% and 82.6% per patient, segment and stone, respectively. The diameter measured on the virtual noncontrast phase corresponded to a mean ± SD 92.5% ± 31.6% of the diameter on the true noncontrast phase. The mean effective dose was 4.8 ± 1.8 and 10.5 ± 3.7 mSv for the true and virtual noncontrast phases, respectively.The proposed protocol allows for combining 3 phases in a single scan while still enabling the detection of urinary stones at high sensitivity. This technique halves the radiation dose and provides the surgeon with better anatomical information on the calyceal system. Therefore, it is a valuable diagnostic tool for kidney stone treatment planning and followup.

PURPOSE: To explore the effects of computed tomography (CT) slice thickness and reconstruction algorithm on quantification of image features to characterize tumors using a chest phantom. MATERIALS AND METHODS: Twenty-two phantom lesions of known sizes (10 and 20 mm), shapes (spherical, elliptical, lobulated, and spiculated), and densities [-630, -10, and +100 Hounsfield Unit (HU)] were inserted into an anthropomorphic thorax phantom and scanned three times with relocations. The raw data were reconstructed using six imaging settings, i.e., a combination of three slice thicknesses of 1.25, 2.5, and 5 mm and two reconstruction kernels of lung and standard. Lesions were segmented and 14 image features representing lesion size, shape, and texture were calculated. Differences in the measured image features due to slice thickness and reconstruction algorithm were compared using linear regression method by adjusting three confounding variables (size, density, and shape). RESULTS: All 14 features were significantly different between 1.25 and 5 mm slice images. The 1.25 and 2.5 mm slice thicknesses were better than 5 mm for volume, density mean, density SD gray-level co-occurrence matrix (GLCM) energy and homogeneity. As for the reconstruction algorithm, there was no significant difference in uni-dimension, volume, shape index 9, and compactness. Lung reconstruction was better for density mean, whereas standard reconstruction was better for density SD. CONCLUSIONS: CT slice thickness and reconstruction algorithm can significantly affect the quantification of image features. Thinner (1.25 and 2.5 mm) and thicker (5 mm) slice images should not be used interchangeably. Sharper and smoother reconstructions significantly affect the density-based features.