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The transposition of EU Directive 2013/59/Euratom into German law requires that patients be informed about the radiation risk of radiological procedures. Such information is not the same as a medical informed consent about immediate risks associated with the procedure, such as deterministic radiation damage, risks of contrast media, or complications. The sole use of X‑rays in diagnostic procedures therefore requires no informed consent in most cases., (© 2022. The Author(s), under exclusive licence to Springer Medizin Verlag GmbH, ein Teil von Springer Nature.)

Background: Bell´s palsy is the most common cause of facial paralysis worldwide and the most common disorder of the cranial nerves. It is a diagnosis of exclusion, accounting for 60-75% of all acquired peripheral facial nerve palsies. Our case shows the first case of a microcystic adnexal carcinoma-like squamous cell carcinoma as a cause of facial nerve palsy., Case Presentation: The patient, a 70-year-old Caucasian male, experienced subsequent functional impairment of the trigeminal and the glossopharyngeal nerve about 1½ years after refractory facial nerve palsy. An extensive clinical work-up and tissue biopsy of the surrounding parotid gland tissue was not able to determine the cause of the paralysis. Primary infiltration of the facial nerve with subsequent spreading to the trigeminal and glossopharyngeal nerve via neuroanastomoses was suspected. After discussing options with the patient, the main stem of the facial nerve was resected to ascertain the diagnosis of MAC-like squamous cell carcinoma, and radiochemotherapy was subsequently started., Conclusion: This case report shows that even rare neoplastic etiologies should be considered as a cause of refractory facial nerve palsy and that it is necessary to perform an extended diagnostic work-up to ascertain the diagnosis. This includes high-resolution MRI imaging and, as perilesional parotid biopsies might be inadequate for rare cases like ours, consideration of a direct nerve biopsy to establish the right diagnosis.

Tumors of the head and neck are predominantly squamous cell carcinomas and those of the salivary glands are predominantly adenocarcinomas, adenoid cystic carcinomas and mucoepidermoid carcinomas. In 2011 the incidence of tumors of the oral cavity and pharynx in Germany was 6839 (5026 male and 1813 female) and of the larynx 1878 (1642 male and 236 female). The incidence of tumors of the nose and paranasal sinuses (467) and salivary glands (470) were much lower (www.krebsdaten.de/abfrage). The primary aim of imaging in head and neck cancer is staging of the disease and a precise assessment of tumor invasion. This information is essential for therapy decision-making (i. e. surgery or radiochemotherapy), planning of the extent of resection and subsequent reconstructive measures and also estimation of functional deficits after therapy. Computed tomography (CT) and magnetic resonance imaging (MRI) are the imaging modalities of choice but both have specific advantages and disadvantages. In certain cases both CT and MRI need to be performed for accurate treatment planning.

Background and Purpose: Metal artifacts from dental fillings and other devices degrade image quality and may compromise the detection and evaluation of lesions in the oral cavity and oropharynx by CT. The aim of this study was to evaluate the effect of iterative metal artifact reduction on CT of the oral cavity and oropharynx., Materials and Methods: Data from 50 consecutive patients with metal artifacts from dental hardware were reconstructed with standard filtered back-projection, linear interpolation metal artifact reduction (LIMAR), and iterative metal artifact reduction. The image quality of sections that contained metal was analyzed for the severity of artifacts and diagnostic value., Results: A total of 455 sections (mean ± standard deviation, 9.1 ± 4.1 sections per patient) contained metal and were evaluated with each reconstruction method. Sections without metal were not affected by the algorithms and demonstrated image quality identical to each other. Of these sections, 38% were considered nondiagnostic with filtered back-projection, 31% with LIMAR, and only 7% with iterative metal artifact reduction. Thirty-three percent of the sections had poor image quality with filtered back-projection, 46% with LIMAR, and 10% with iterative metal artifact reduction. Thirteen percent of the sections with filtered back-projection, 17% with LIMAR, and 22% with iterative metal artifact reduction were of moderate image quality, 16% of the sections with filtered back-projection, 5% with LIMAR, and 30% with iterative metal artifact reduction were of good image quality, and 1% of the sections with LIMAR and 31% with iterative metal artifact reduction were of excellent image quality., Conclusions: Iterative metal artifact reduction yields the highest image quality in comparison with filtered back-projection and linear interpolation metal artifact reduction in patients with metal hardware in the head and neck area., (© 2015 by American Journal of Neuroradiology.)

Introduction | The philosophy on how to improve cardiometabolic risk factors most efficiently by endurance exercise is still controversial. To determine the effect of high-intensity (interval) training (HI[I]T) vs. moderate-intensity continuous exercise (MICE) training on cardiometabolic risk factors we conducted a 16-week crossover randomized controlled trial. Methods | 81 healthy untrained middle aged men were randomly assigned to a HI(I)T-group and a control-group that started the MICE running program after their control status. HI(I)T consisted of running exercise around or above the individual anaerobic threshold (≈ 80- 100 % HRmax); MICE focused on continuous running exercise at ≈ 65-77.5 % HRmax. Both protocols were comparable with respect to energy consumption. Study endpoints were cardiorespiratory fitness (VO2max), left ventricular mass index (LVMI), metabolic syndrome Z-score (MetS-Z-score), intima-media-thickness (IMT) and body composition. Results | VO2max-changes in this overweighed male cohort significantly (p=0.002) differ between HIIT (14.7 ± 9.3 %, p=0.001) and MICE (7.9 ± 7.4 %,p=0.001). LVMI, as determined via magnetic resonance imaging, significantly increased in both exercise groups (HIIT: 8.5 ± 5.4 %, p=0.001 vs. MICE: 5.3 ± 4.0 %, p=0.001), however the change was significantly more pronounced (p=0.005) in the HIIT-group. MetS-Z-score (HIIT: -2.06 ± 1.31, p=0.001 vs. MICE: -1.60 ± 1.77, p=0.001) and IMT (4.6 ± 5.9 % p=0.011 vs. 4.4 ± 8.1 %, p=0.019) did not show significant group-differences. Reductions of fat mass (-4.9 ± 9.0 %, p=0.010 vs. -9.5 ± 9.4, p=0.001) were significantly higher among the MICE-participants (p=0.034), however, the same was true (p=0.008) for lean body mass (0.5 ± 2.3 %, p=0.381 vs. -1.3 ± 2.0 %, p=0.003). Conclusion | In summary high-intensity interval training tends to impact cardiometabolic health more favorable compared with a moderate-intensity continuous endurance exercise protocol., (© Georg Thieme Verlag KG Stuttgart · New York.)

Aim: Hybrid single-photon emission tomographic (SPECT) and X-ray computed tomography (CT) systems are increasingly used in oncologic imaging. With SPECT/CT not only the thoracic spine but also the surrounding soft tissue needs to be evaluated for pathological findings. The purpose of this study was to assess the prevalence of non-osseous findings detectable on low-dose CT datasets from patients studied by thoracic 99mTc-dicarboxypropane diphosphonate (DPD)-SPECT/CT., Patients, Methods: 119 consecutive oncologic patients (81 breast cancer, 38 with other cancer) who underwent DPD-SPECT CT of the thoracic region were included in this study. Non-osseous findings on CT were classified as either probably benign or suspicious. Suspicious findings were correlated with retrievable previous imaging and if performed with follow up imaging (MRI, CT with contrast medium, Ultrasound) or biopsy results., Results: In 80/119 (67%) patients no imaging was performed before SPECT/CT. Only 7/119 subjects (6%) had no other lesions than bone lesions. In 101/119 (85%) patients lesions found on SPECT/CT images were rated as benign and in 65/119 (55%) patients as suspicious. In 8/119 (7%) patients with previously unknown suspicious lesions on SPECT/CT images suspicious findings were confirmed by biopsy., Conclusion: 7% of patients referred to SPECT/CT of the thoracic spine for staging of malignant disease had previously unknown suspicious non-osseous lesions detectable on the low-dose CT images which were confirmed by biopsy. This could be especially relevant for cancer entities like breast and prostate, in which no thorax-CT is routinely intended for staging.

Objectives: The goal of the present work was to assess various computed tomography (CT) systems in term of image quality and organ doses, namely five cone-beam CT (CBCT) scanners operated at standard settings and three multislice CT (MSCT) scanners operated at greatly dose-reduced settings., Materials and Methods: Radiographic volume scans were taken on a complete human cadaveric head specimen and the image quality of each was rated by four experienced examiners according to specific skeletal structures and bone-soft tissue interfaces. Radiation doses were captured by a head-and-neck phantom (Rando; Alderson Research Laboratories). Standard protocols were used for the CBCT scans. For the MSCT scans, tube voltage and current were adjusted to minimize radiation without compromising image quality., Results: Interobserver agreement was close to perfect, with iota coefficients of 0.931 (95% CI 0.807-0.978) between groups 1 and 2 and 0.959 (95% CI 0.869-1.000) between groups 1 and 3. Ratings of image quality in terms of skeletal-structure representation were slightly better for the CBCT than the MSCT scanners, although these differences were not statistically significant. The two groups of scanners applied considerably different organ doses: the lowest dose (0.03 mSv) was measured on the bone surface with a CBCT unit (Picasso Trio® from Vatech) and the highest dose (8.30 mSv) in the vicinity of the eye lens with another CBCT unit (3D Accuitomo 170® from J. Morita)., Conclusion: The various systems tested offer similar imaging quality but demonstrated distinct differences in organ dose levels. The decision on which approach to take is not between CBCT and MSCT but rather between specific models and parameter settings. If these are optimized, MSCT images providing useful clinical information can be obtained at much reduced levels of radiation. Depending on the model and setting used, MSCT radiation levels may even be lower than during CBCT scans.

Objective: Assessment of aortic annulus dimensions prior to transcatheter aortic valve implantation (TAVI) is crucial for accurate prosthesis sizing in order to avoid prosthesis-annulus-mismatch possibly resulting in complications like valve dislodgement, paravalvular regurgitation or annulus rupture. Contrast-enhanced multidetector computed tomography allows 3-dimensional assessment of aortic annulus dimensions. Only limited data exist about its interobserver variability., Methods: In 100 consecutive patients with symptomatic severe aortic stenosis (51 male, BMI 27±5kg/m(2), age 81±7 years, heart rate 72±15bpm, Logistic Euroscore 31±14%, STS-Score 7±4%), pre-interventional aortic annulus assessment was performed by dual source computed tomography (collimation 2×128×0.6mm, high pitch spiral data acquisition mode, 40-60ml contrast agents, radiation dose 3.5±0.9mSv). The following aortic annulus characteristics were determined by three independent observers: aortic annulus maximum, minimum and mean diameters (Dmax, Dmin, Dmean), eccentricity index (EI), effective aortic annulus diameter according to its circumference (Dcirc), effective aortic annulus diameter according to its area (Darea), distance from the aortic annulus plane to the left (LCA) and right coronary artery (RCA) ostia, maximum (DmaxAR) and minimum aortic root diameter (DminAR), maximum (DmaxSTJ) and minimum diameter of the sinotubular junction (DminSTJ). Subsequently, interobserver variabilities were assessed., Results: Correlation between the three observers showed moderate to close agreement (between r=0.67 and r=0.97, all p<0.001). Mean differences (SE) between the three observers ranged from 0.07 (0.06)mm to 0.24 (0.07)mm for assessing the mean AA diameter (Dmean), from 0.28 (0.04)mm to 0.60 (0.06)mm for determining the effective AA diameter derived from the annulus area (Darea) and from 0.03 (0.07)mm to 0.07 (0.11)mm derived from the AA perimeter (Dcirc). For measurements of LCA and RCA distances to the AA level, mean interobserver differences (SE) ranged from 0.36 (0.07)mm to 0.76 (0.09)mm and from 0.15 (0.06)mm to 0.45 (0.11)mm., Conclusion: Computed tomography provides reproducible measurements of the aortic annulus and root geometry in patients scheduled for TAVI. The perimeter-derived aortic annulus diameter shows the lowest interobserver differences. Interobserver variabilities in prosthesis size recommendation were further reduced, if all three sizing methods were considered and stated as a "consensus result"., (Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.)

Percutaneous renal biopsy (PRB) of kidney transplants might be prevented by an elevated risk of bleeding or limited access to the allograft. In the following, we describe our initial experience with 71 transvenous renal transplant biopsies in 53 consecutive patients with unexplained reduced graft function who were considered unsuitable candidates for PRB (4.2% of all renal transplant biopsies at our institution). Biopsies were performed via the ipsilateral femoral vein with a renal biopsy set designed for transjugular renal biopsy (TJRB) of native kidneys. Positioning of the biopsy system within the transplant vein was achievable in 58 of 71 (81.7%) procedures. The specimen contained a median of 10 glomeruli (range 0-38). Tissue was considered as adequate for diagnosis in 56 of 57 (98.2%) biopsies. With respect to BANFF 50.9% of the specimen were adequate (>10 glomeruli), 47.4% marginally adequate (1-9 glomeruli) and 1.8% inadequate (no glomeruli). After implementation of real-time assessment all specimen contained glomeruli. One of the fifty-eight (1.8%) procedure-related major complications occurred (hydronephrosis requiring nephrostomy due to gross hematuria). Transfemoral renal transplant biopsy (TFRTB) is feasible and appears to be safe compared to PRB. It offers a useful new alternative for histological evaluation of graft dysfunction in selected patients with contraindications to PRB., (© Copyright 2013 The American Society of Transplantation and the American Society of Transplant Surgeons.)

Purpose: To check the feasibility of the easy quantification of tumor vascularization derived from dynamic contrast-enhanced ultrasound (DCE-US) in comparison to dynamic contrast-enhanced computed tomography (DCE-CT) in patients with hepatocellular carcinoma (HCC)., Materials and Methods: 19 patients with cirrhosis and histologically proven HCC prospectively underwent CEUS (SonoVue) and CT (Imeron400). Following CEUS, the software ImageJ was used for the easy quantification of the echogenicity in HCC lesions and tumor-free liver parenchyma. For DCE-CT we used the software Hepacare and created arterial enhancement fraction color maps of the whole liver and HCC lesions., Results: Unifocal/multifocal HCCs were detected in 12/7 (US) and 10/9 patients (CT) and biopsied nodules were defined as a reference lesion with a median of 40 mm (US) and 42 mm (CT). CEUS showed HCC-typical hyper-/hypoenhancement in the arterial/late phase in 16/19 reference lesions, while all reference lesions showed an HCC-typical vascular pattern in CT. With DCE-US, quantitative assessment could not be performed in 3/19 patients due to respiratory motion or insufficient image quality. 13/16 reference lesions showed an HCC-typical vascular pattern. Quantitative assessment was possible with DCE-CT in all patients and all reference nodules showed HCC-typical values of the arterial enhancement fraction. There was no statistical difference between CEUS, DCE-US and DCE-CT in the quantitative assessment of contrast enhancement., Conclusion: The quantitative evaluation of DCE-US was feasible in HCC without a statistical difference with respect to DCE-CT. Further studies with a larger study population including small nodules ≤ 2 cm are needed to assess whether this technique is helpful in routine ultrasound., (© Georg Thieme Verlag KG Stuttgart · New York.)

A 33-year old patient presented at our outpatient department with pulse-synchronous tinnitus in the left ear of several years' standing. Examination of the left ear showed a neoplasm at the base of the meatus in front of the ear drum. In addition, there was paresis of the right hypoglossal nerve and right vocal cord. CT scan showed multiple paraganglioma in the head and neck region. Molecular genetic screening analysis showed a mutation of the SDHD gene and thus the diagnosis of paraganglioma syndrome type 1 was made. In the treatment concept presented here the main goal was preservation of function of the left cranial nerves due to the functional loss of the right cranial nerves X and XII. This goal could be achieved by means of a staged procedure in collaboration with radiotherapists.

Background and Purpose: Computed tomography is an essential modality for imaging of the temporal bone. Newest generation scanners allow the coverage of large examination volumes with a single gantry rotation. The objective of this study was to compare a 128-section SST (1 single rotation of the x-ray tube) with conventional spiral MSCT (ultra-high-resolution mode) for imaging of the temporal bone., Materials and Methods: Fifty-four temporal bones in 27 patients were scanned with both a conventional MSCT and 128-section SST. After blinding and randomization of both examinations, 2 observers assessed the visualization of 38 anatomic structures (eg, various segments of the facial nerve canal, mallear ligaments) by using multiplanar reconstructions in the axial and coronal planes. The differences in evaluation scores obtained for the 2 techniques were analyzed by using a Wilcoxon signed rank test, with a P value of < .05 considered significant. For both methods, imaging time and radiation exposure were noted., Results: Overall visualization of anatomic structures did not differ significantly between the 2 techniques (P > .05). When we compared the anatomic structures separately, there was better visualization of the lateral mallear ligament with MSCT, whereas the cochlear septa were ranked higher with SST (P < .05). Imaging time and average DLP for MSCT were 12.3 seconds and 306 mGy cm, respectively; for SST, values they were 1 second and 64 mGy cm, respectively (ie, a dose reduction of 79%)., Conclusions: For imaging of the temporal bone with adequate diagnostic quality, 128-section SST can be used. The main advantages over MSCT are the dramatic reductions of imaging time and radiation exposure, which are particularly important when scanning uncooperative patients or children.

We report on an 80-year-old hypertensive patient with a left-sided high-grade carotid stenosis who developed transient monoparesis of the right arm after stenting of the carotid artery. Computed tomography (CT) of the brain (cranial CT) performed immediately after the symptomatic had begun showed a linear hyperdensity in the ipsilateral, precentral sulcus with a moderate, local brain swelling and edema. Transcranial doppler sonography revealed an accelerated post-interventional systolic blood flow velocity and in the ipsilateral medial cerebral artery compared to the preoperative value and an increased cerebral blood flow, so that the diagnosis of hyperperfusion syndrome with a subpial hematoma was confirmed. After strict blood pressure control and -reduction the neurological deficit regressed gradually and the hyperdensity had completely disappeared in control CCT after 15 h.

Purpose: The article describes an experimental phantom study of a system for digital full field mammography with a new digital detector with a double plate of pure selenium., Materials and Methods: The experiments were carried out with the new full field digital mammography system Amulet from FujiFilm. This system has a new detector (18×24 cm(2)) on the basis of highly purified amorphous selenium (a-Se) with a pixel size of 50 µm. The x-rays are converted into electric signals in the first plate which are read into the second plate with the help of an optical switch and demonstrated in the form of an image. In this way a better pixel size/volume and signal-to-noise ratio should be achieved. The object of the investigation was the Wisconsin Mammographic Random Phantom, Model 152 A (Technical Performance Mo/Mo, 28 kV, 100 mAs). Five investigators with different experiences in mammography each received three images on a monitor with different random positions of the simulated lesions in the phantom for assessment. The detection rates were compared under the same conditions with the results of two other full field digital mammography systems., Results: The median detection rate for all images and investigators for the new doubled plated a-Se detector with optical switch was 98.7%. For both other systems with a-Si or and a-Se detectors the detection rate was 89.8% or 97.3%, respectively. There were no significant differences in the detection rate of the simulated breast lesions for all three systems considering the interobserver and intraobserver variation., Conclusion: The first phantom study for the detection of simulated breast lesions with the new full field digital mammography system Amulet demonstrates equivalent results with the other systems used in the clinical routine. The trend towards superiority of the new system has to be confirmed in further clinical studies.

Purpose: The aim of this retrospective clinical study was to compare the diagnostic accuracy of the novel 50 µm FFDM (full-field digital mammography) system (DR) with an established 70 µm system (DR) in the differential diagnosis between benign and malignant clusters of microcalcification (n=50) (BI-RADS™ classification 4/5) and to assess the possible incremental value of the 50 µm pixel-pitch on specificity., Material and Methods: From March 2009 to September 2009, 50 patients underwent full-field digital mammography (FFDM) (detector resolution 70 µm) (Novation, Siemens, Erlangen, Germany). As there were suspicious signs of microcalcification classified with BI-RADS™ 4/5 after diagnosis and preoperative wire localization, control images were made with the new FFDM system (detector: resolution 50 µm) (Amulet, Fujifilm, Tokyo, Japan) with the same exposure parameters. The diagnosis was determined after the operation by five radiologists with different experience in digital mammography from randomly distributed mediolateral views (monitor reading) whose results were correlated with the final histology of all lesions., Results: Histopathology revealed 19 benign and 31 malignant lesions in 50 patients after open biopsy. The results of the five readers showed a higher sensitivity of the new FFDM system (80.0%) in the ability to recognize malignant microcalcification in comparison to the established system (74.8%). The specificity (75.8 versus 71.6%) was slightly higher for the new system but these results were not statistically significant (p<0.001). Considering the diagnostic accuracy, the new system (detector: resolution 50 µm) was also slightly superior to the well-known system (detector: resolution 70 µm) (80.1% versus 76.4%)., Conclusions: Our study has shown that the new full-field digital mammography system using the novel detector compared with the already established FFDM system with respect to the assessment of microcalcification is at least equivalent.

Congenital heart diseases are the most common congenital abnormalities of development. In general, echocardiography and cardiac catheter angiography are considered the gold standard for the evaluation of congenital heart disease. Cardiac magnetic resonance imaging has become an important supplementary imaging modality because of its ability to provide an accurate morphological and functional evaluation. The role of cardiac computed tomography in the imaging of patients with congenital heart disease is becoming increasingly more important due to the development of low radiation dose protocols and improvements in the spatial and temporal resolution. In the preoperative depiction and follow-up after surgical repair of congenital heart diseases, cardiac computed tomography provides detailed information of the heart, the venous and arterial pulmonary circulation as well as systemic arteries. This article reviews the technical aspects of cardiac CT and the modification of examination protocols according to the expected pathology and patient age. The potentials and limitations of the various radiation dose reduction strategies are outlined.

The oropharynx is an interface between the airway and the digestive tract. Clinical evaluation and endoscopy suffice for the diagnosis of a variety of lesions, but tumors require cross-sectional imaging to assess local infiltration depth and lymphatic spread. This article discusses different lesions of the oropharynx with respect to imaging characteristics of CT and MRI, with a focus on resectability issues and decision-making.

Coronary artery fistula is a rare vascular anomaly in which there is abnormal communication between the coronary artery and the great vessels or cardiac chambers. We report the case of a 66-year-old man with two separate coronary artery to pulmonary artery fistulas (one of which demonstrated multiple aneurysms), which were diagnosed on dual-source 64-slice coronary CT and reconfirmed by coronary catheter angiography.

Purpose: Evaluation of the diagnostic value of breast specimen imaging with a digital mammographic system using a detector system with changeable pixel size compared to standard mode imaging in different monitor display modes., Materials and Methods: Using the digital mammographic system SenoScan (Fischer Imaging, Denver, USA), 50 diagnostic breast specimens with microcalcifications were visualized in both standard mode (pixel size 54 microm) and high resolution mode (pixel size 27 microm). The resulting radiographs were displayed 1:1 on a monitor. Standard mode images (pixel size 54 microm) were additionally displayed in a 2:1 mode. A total of 5 readers with different mammographic experience analyzed the type of the microcalcifications on the basis of the different display modes. The images were presented randomly. The findings were subsequently compared to the histology., Results: The high resolution mode yielded slightly but not significantly better results than the standard mode on average for all 5 readers. Compared to a sensitivity of 80 % and a specificity of 72 % (PPV = 74 %, NPV = 78 %) in the standard mode, the high resolution mode provided a sensitivity of 86 % and a specificity of 74 % (PPV = 77 %, NPV = 83 %). The standard mode images on a 2:1 monitor display yielded 84 % and 74 % (PPV = 76 %, NPV = 82 %)., Conclusion: The high resolution mode did not significantly increase the sensitivity and specificity of the microcalcification reading. A similar improvement was achieved by the 2:1 display mode, i. e. digital monitor zooming. For the clinical situation this means that there is no diagnostic advantage from using a high resolution target view with this mammographic system.

Purpose: Reduction of radiation exposure at an adequate image quality by optimizing the radiation quality for a new system of full-field digital mammography using a digital detector (a-Se)., Materials and Methods: The investigations were performed using a digital mammography system Novation (Siemens, Erlangen). The system was constructed with a bimetal anode (molybdenum and tungsten) and the possibility of changing the filter (molybdenum/rhodium). The test object was the Wisconsin Mammography Random Phantom Model 152 A (Radiation Measurements Inc.) of which images were acquired using the digital technique with the tungsten anode and rhodium filter at different tube voltages (26-35 kV) and tube loads (40-100 mAs) and compared to images in the molybdan/molybdan molybdenum/molybdenum technique. To quantify the image quality, we used the detection rate of the simulated lesions in the phantom., Results: Increasing the tube voltage significantly decreases the average glandular dose when using AEC (Automatic Exposure Control), i. e., constant detector dose. At the same time, the image quality decreases significantly with respect to the detection rate (26 kV, 1 mGy, 95.1 %; 35 kV, 0.7 mGy, 82.7 %). As a good compromise between the necessary diagnostic image quality and the lowest dose exposition, 28 kV and 60 mAs were selected for imaging with the tungsten/rhodium anode/filter combination. A further change to the tube load did not make sense because a decrease of 10 % resulted in a significant decrease in the detection rate while only a 2 % increase in detection rate was achieved for a 65 % increase in radiation exposure., Conclusion: The results of this phantom study demonstrate that the routine use of the tungsten anode in combination with a rhodium filter for full-field digital mammography with an a-Se detector in contrast to a molybdan/molybdan molybdenum/molybdenum anode/filter combination results in a reduction of the average glandular dose of up to 30 % without loss of diagnostic image quality.

Solitary fibrous tumors (SFT) are rare, mostly fibroblastic tumors usually situated in the pleura. Extrapleural manifestations have been described. However, the oral cavity is an uncommon localisation of this tumor. We report the very unusual case of an SFT affecting the tongue that could be removed completely because of its clear delineation. Intraoperative incisional biopsies were used to exclude malignancy. For definitive classification of the tumor, additional histopathologic examinations had to be carried out. Because SFT exhibit malignant behavior only in exceptional cases and their recurrence after complete removal has never been encountered, surgery can focus on the preservation of undisturbed function of the tongue.

We describe the rare entity of an intraosseous meningioma arising in the mandible. The meningioma was found incidentally in an asymptomatic adult patient on dental radiography, mimicking other cystic-appearing jaw masses. The CT and MR imaging features of mandibular meningioma are reviewed with reference to prior published descriptions of this unusual entity.

Background and Purpose: We prospectively evaluated the influence of different imaging techniques (time-of-flight MR angiography [TOF-MRA], contrast-enhanced MR angiography [CE-MRA], multisection CT angiography [CTA]) and postprocessing methods (maximum intensity projection [MIP], multiplanar reformation [MPR]) on carotid artery stenosis grading., Materials and Methods: Fifty patients (34 men, 16 women) with symptomatic stenosis of the internal carotid artery were examined with a 16-section spiral CT and a 1.5T MR unit. Two MRA techniques were applied: 3D-TOF and CE-MRA. MPR was used for postprocessing with all modalities; MIP was used only with MRA. Four readers measured and calculated the percentage diameter stenosis independently according to NASCET criteria. The Wilcoxon test was used to measure interobserver variability, and the Friedman test was used to test the null-hypothesis of equality of the modalities., Results: The hypothesis for global equality was rejected (P < .001). TOF-MRA and CTA assessed with MPR showed the highest concordance (difference, 0.6%; confidence interval [CI], -3.0, 4.3%), and CE-MRA with MIP and CTA showed the lowest concordance in stenosis grading (difference, 7.0%; CI, 3.4, 10.6%). MPR resulted in lower degrees of stenosis than MIP for both MRA sequences, although not statistically significant (CE, -3.0%; CI, -6.6, 0.6%; TOF, -2.2%; CI, -5.8, 1.4%). When only studies with good or excellent image quality were considered, the differences decreased, but the trends remained., Conclusion: Stenosis grading is dependent on the examination method and postprocessing technique. CTA and TOF-MRA evaluated with MPR revealed highest concordance.

Purpose: To compare the sensitivity of conventional two-dimensional (2D) projection imaging with tomosynthesis with respect to the detectability of mammographic phantom lesions., Materials and Methods: Using a breast tomosynthesis prototype based on a commercial FFDM system (Siemens MAMMOMAT Novation), but modified for a wide angle tube motion and equipped with a fast read-out amorphous selenium detector, we acquired standard 2D images and tomosynthesis series of projection views. We used the Wisconsin mammographic random phantom, model RMI 152A. The anode filter combinations Mo/Mo and W/Rh at two different doses were used as typical radiographic techniques. Slice images through the phantom parallel to the detector were reconstructed with a distance of 1 mm employing a filtered back-projection algorithm. The image data sets were read by five radiologists and evaluated with respect to the detectability of the phantom details., Results: For all studied radiographic techniques, the detection rate in the tomosynthesis mode was 100 %, i. e. 75 true positive findings out of 75 possible hits. In contrast, the conventional projection mode yielded a detection rate between 80 and 93 % (corresponding to 60 and 70 detected details) depending on the dose and X-ray spectrum., Conclusion: Tomosynthesis has the potential to increase the sensitivity of digital mammography. Overlapping structures from out-of-plane tissue can be removed in the tomosynthesis reconstruction process, thereby enhancing the diagnostic accuracy.

Fifty-one patients were examined with bone subtraction CT angiography (BSCTA). Data were acquired on 4-and 64-slice spiral CT systems. The post-processing method is based on fully automatic registration of non-enhanced and contrast-enhanced CT data and subsequent selective bone removal. Vascular structures and brain tissue are retained with the original CTA noise level. Image quality and delineation of the pathologic process were assessed and artifacts introduced by the bone removal process recorded. The bone subtraction algorithm worked successfully in all examinations. The processing time was 6 min on average. Image quality was rated excellent in 20 (39%), good in 26 (51%) and acceptable in 5 (10%) patients. Ophthalmic arteries were visible in 12 (24%) patients bilaterally, in 13 (25%) patients unilaterally and in 26 (51%) patients at least at the origin. BSCTA improved visualization of the infraclinoid ICA and the vertebral arteries. The depiction of stenosis of the extracranial ICA and supraclinoid aneurysms was not significantly improved. In patients with suspicion of sinus thrombosis, BSCTA and conventional CTA yielded similar results. To conclude, BSCTA improves the visualization of vessels with close contact to bone and can improve the diagnostic accuracy and therapy planning of infraclinoid aneurysms.

Purpose: CT angiography (CTA) has been established for detection and therapy planning of intracranial aneurysms. The analysis of aneurysms at the level of the skull base, however, remains difficult because bone prevents a free view. We report initial clinical results of an approach for automatic bone elimination from CTA data., Material and Methods: Before the bone-removal process 2 datasets are acquired: nonenhanced spiral CT with reduced dose and contrast-enhanced CTA. The software automatically registers the nonenhanced data onto the CTA data and selectively removes bone. Vascular structures, as well as brain tissue, remain visible. In this study, we investigated 27 patients with 29 aneurysms, 13 of which were located at the skull base. 3D volume-rendered images with and without bone removal were reviewed and compared with digital subtraction angiography by 2 radiologists in consensus., Results: All supraclinoidal aneurysms were detected on 3D volume-rendered images of both CTA and bone-subtraction CT angiography (BSCTA). Four intracavernous and 3 paraclinoid aneurysms of the internal carotid artery were not visible or were only partially visible on conventional 3D CTA, whereas they could be optimally visualized with BSCTA. Bone removal was successful in all patients; the average additional time for postprocessing was 6.2 minutes. In 7 patients (26%), perfect bone removal without any artifacts was achieved. In most patients, some bone remnants were still present, though it did not disturb the 3D visualization of vascular structures., Conclusion: BSCTA allows robust and fast selective elimination of bony structures, thus ascertaining a better analysis of arteries at the level of the skull base. This is useful for both detection and therapy planning of intracranial aneurysms.

The broad introduction of multi-slice CT by all major vendors in 1998 was a milestone with regard to extended volume coverage, improved axial resolution and better utilization of the tube output. New clinical applications such as CT-examinations of the heart and the coronary arteries became possible. Despite all promising advances, some limitations remain for 4-slice CT systems. They come close to isotropic resolution, but do not fully reach it in routine clinical applications. Cardiac CT-examinations require careful patient selection. The new generation of multi-slice CT-systems offer simultaneous acquisition of up to 16 sub-millimeter slices and improved temporal resolution for cardiac examinations by means of reduced gantry rotation time (0.4 s). In this overview article we present the basic technical principles and potential applications of 16-slice technology for the example of a 16-slice CT-system (SOMATOM Sensation 16, Siemens AG, Forchheim). We discuss detector design and dose efficiency as well as spiral scan- and reconstruction techniques. At comparable slice thickness, 16-slice CT-systems have a better dose efficiency than 4-slice CT-systems. The cone-beam geometry of the measurement rays requires new reconstruction approaches, an example is the adaptive multiple plane reconstruction, AMPR. First clinical experience indicates that sub-millimeter slice width in combination with reduced gantry rotation-time improves the clinical stability of cardiac examinations and expands the spectrum of patients accessible to cardiac CT. 16-slice CT-systems have the potential to cover even large scan ranges with sub-millimeter slices at considerably reduced examination times, thus approaching the goal of routine isotropic imaging.

Methods of determining plaques in the extracranial internal carotid artery are ultrasound, computed tomography (CT) and magnetic resonance imaging (MRI). The goal of this overview is to introduce these methods and discuss their diagnostic and clinical significance. Ultrasound has the capability of showing the echogenity of the plaques. This method seems to demonstrate a relationship with the incidence of hemispheric symptoms. A histological association could only rarely be seen. The surface structure can only be clearly and correctly evaluated in individual cases under optimal circumstances. Computed tomography is capable of showing the calcium content and specific site of the plaques. However, lipid content and fibrous tissue cannot be deduced reliably. The currently available image resolutions limit a detailed imaging of surface characteristics. Magnetic resonance imaging provides, in vitro, a correct rendering of plaque composition and endoluminal surface structure. In vivo it is possible to recognize both the fibrous cap and necrotic core as well as intraplaque hemorrhage. Because of certain artefacts more detailed images are difficult to interpret. In conclusion, further clinical trials should reveal, whether these methods can be set in clinical routine to detect plaque surface and morphology for stratifying patients at risk of hemispheric symptoms during the spontaneous course as well as during carotid interventions.

Purpose: To determine the diagnostic accuracy of microcalcifications and focal lesions in a retrospective clinical-histological study using high-resolution digital phosphor storage plates (hard copy) and full-field digital mammography (hard copy)., Materials and Methods: From May 2003 to September 2003, 102 patients underwent digital storage plate mammography (CR), using a mammography unit (Mammomat 3000 N, Siemens) in combination with a high resolution (9 lp/mm) digital storage phosphor plate system (pixel size 50 microm) (Fuji/Siemens). After diagnosis and preoperative wire localization, full-field digital mammography (CCD) (DR) was performed with the same exposure parameters. The full-field digital mammography used a CCD-detector (SenoScan) (Fisher Imaging) with a resolution of 10 Ip/mm and a pixel size of 50 microm. Five investigators determined the diagnosis (BI-RADS I - V) retrospectively after the operation from randomly distributed mediolateral views (hard copy reading). These results were correlated with the final histology., Results: The diagnostic accuracy of digital storage plate mammography (CR) and full-field digital mammography (CCD) (DR) was 73 % and 71 % for all findings (n = 102), 73 % and 71 % for microcalcifications (n = 51), and 72 % and 70 % for focal lesions (n = 51). The overall results showed no difference., Conclusion: Our findings indicate the equivalence of high-resolution digital phosphor storage plate mammography (CR) and full-field digital mammography (CCD) (DR).

Noninvasive modalities like CTA are increasingly replacing selective angiography in the evaluation of carotid artery stenosis. Dedicated scan protocols and contrast injection techniques are mandatory for the morphological assessment of carotid artery stenosis. These protocols need to be adapted to different scanner types. The delineation of plaque components and the residual lumen is improved with high resolution scan protocols and dedicated reconstruction algorithms. The exact delineation of in-stent stenosis remains limited. Standardization of postprocessing is crucial in order to attain reproducible results. Multislice spiral CT allows reliable grading of carotid artery stenosis. Relevant venous opacification and pulsation artifacts have to be expected with 4-slice scanners, the short scan time of the latest CT scanners minimize these problems.

Objectives: The aim of this study was to compare methods of quantifying calcification of the internal carotid artery., Materials and Methods: We examined 92 internal carotid artery endarterectomy specimens. Grey scale median (GSM) values were calculated from optimized B-mode scans. The degree of calcification was assessed using radiographic calcification grading. Plaques were processed histologically, and classified into: (1) calcium-rich hard plaques, (2) lipid-rich soft plaques, and (3) combined plaques. The specimens were scanned in CT-scanner. The calcium score was determined as described by Agatston., Results: Histopathology and GSM results concurred in 39 out of 92 cases (kappa=0.088). There was no significant correlation between the calcium score and the median GSM value (R=0.005; P=0.959). Histology and CT morphology showed a significant concordance (P<0.001). Also CT and radiomorphological classification showed close agreement (R=0.628, P<0.001)., Conclusions: Calcium scores calculated using CT morphology enable precise in vitro evaluation of the calcium content of plaques in the internal carotid. In contrast, grey scale median values do not adequately reflect calcification of plaques.

We report a rare case of bilateral orbital metastases as the presentation in a 63-year-old woman. Biopsy of a diffusely infiltrated medial rectus muscle suggested metastatic adenocarcinoma. Investigation revealed a palpable mass of the right breast not shown on mammography or sonography. Invasive lobular carcinoma was found at core-needle biopsy with histological features identical to those of the orbital lesion. Metastases to the extraocular muscles are uncommon, particularly as the initial abnormality in the absence of disseminated disease.

Purpose: Experimental phantom study for the detection of simulated lesions with five different digital and one conventional screen-film mammography system., Materials and Methods: Three radiographs were obtained at various configurations of the phantom with one conventional screen-film system (Mammomat 3000 N) (Siemens), five digital systems (high resolution computed radiography system [Fuji/Siemens], one a-Si detector [GE Medical Systems], two a-Se detectors [Siemens; Hologic / Lorad] and one CCD detector [Fischer Imaging]), applying the same exposure parameters. The Wisconsin Mammographic Random Phantom, Model 152 A, was used. Five investigators with different experience in mammography (3 months to more than 4 years) evaluated the 18 randomly selected radiographs., Results: No significant differences were found in the detection rate of simulated breast lesions for conventional screen-film mammography (84.9 %), high resolution computed radiography (86.7 %) and digital mammography with an a-Si detector (89.8 %). Highly significantly better results (p < 0.001) were found with the two a-Se systems (97.3 %) and the CCD system (100 %)., Conclusion: Conventional screen-film mammography can be replaced by high resolution computed radiography and digital mammography with a-Si-, a-Se- and CCD-detectors. This has to be confirmed in further clinical studies.

Objective: To determine the limits of accuracy of fusion of optical three-dimensional (3D) imaging and computed tomography (CT) with and without metal artefacts in an experimental setting and to show the application of this hybrid system in 3D orthognathic surgery simulation., Methods: Ten plaster casts of dental arches were subjected to a CT scan and optical 3D surface imaging. Subsequently, the first molars in the plaster casts were supplied with metal restorations, bilaterally, and new CT scans and optical surface images were assessed. The registration of the surface data of the two imaging modalities of the study models without and with metal restorations was carried out. The mean distance between the two data sets was calculated. From a patient a CT scan of the skull as well as optical 3D images of plaster casts of the dental arches were acquired. Again the two imaging modalities were registered and virtual orthognathic surgery simulation was carried out., Results: The mean distance between the corresponding data points of CT and optical 3D surface images was 0.1262+/-0.0301 mm and 0.2671+/-0.0580 mm, respectively, for the plaster casts without and with metal restorations. The differences between these data were statistically significant (P<0.0005). For the patient case a mean difference of 0.66+/-0.49 mm and 0.56+/-0.48 mm for mandible and maxilla, respectively, was calculated between CT and optical surface data., Conclusion: The accuracy of the fusion of 3D CT surface data and optical 3D imaging is significantly reduced by metal artefacts. However, it seems appropriate for virtual orthognathic surgery simulation, as post-operative orthodontics are performed frequently.

Aim: To evaluate the potential of three-dimensional ultrasound (3D US) in core biopsy of suspicious breast lesions., Method: 3D US controlled core biopsy was performed in 107 breast masses in 100 women by using an automated biopsy system (11G coaxial needle, 12 G biopsy needle). Mean diameter of the lesions was 1.55 cm (0.5 - 3.5 cm). A linear 3D US volume scanner was used for the procedure. Localization of the lesion and placement of the needle were initially done under 2D US guidance. After core needle stroke a 3D US volume acquisition was performed to correlate lesion and needle position. In the case of eccentric needle position the needle was repositioned under 3D control. 5 specimens were taken from each lesion. The histological results from the specimens were correlated with the results from surgery or clinical follow-up (> 2.5 years)., Results: Biopsy was taken from 59 probably benign (BI-RADS 3 - 4) and 48 malignant (BI-RADS 5) lesions. 3D US revealed 61 central, 44 eccentric and 2 marginal needle positions after the initial 2D guidance. Central repositioning of the needle was achievable under 3D guidance in all patients. Histological examination of the specimens revealed 41 invasive carcinomas and one in-situ carcinoma (DCIS). In one lesion, the carcinoma was missed in the core biopsy, despite central hits of the biopsy needle. This led to a sensitivity of 98 %, specificity of 100 %, PPV of 100 %, NPV of 98.5 % and accuracy of 99 % for the diagnosis of a malignant lesion., Conclusion: 3D US improves needle positioning as well as the depiction of correct needle placement in freehand core biopsy.

Purpose: Experimental investigations of a new digital mammography system., Materials and Methods: The digital mammography system SenoScan (Fischer Imaging) is based on 4 charged coupled devices (CCD) (slot detector). The pixel size is 50 micro m, field of view 21 x 29 cm (2), effective quantum efficiency (DQE) (0) 50 %, spatial resolution 10 lp/mm, and memory depth 12 bit. The object of investigation was the Wisconsin Mammographic Random Phantom, Model 152 A (Radiation Measurements Inc., Wisconsin). The radiograms were acquired using the digital mammography system., Results: The digital mammography detected 225 of 225 possible details. The surface dose was 6.95 mGy., Conclusions: These experimental results support the use of the digital mammography in practice. This has to be confirmed in further clinical trials.

Purpose: To evaluate the potential of raw data-based multidimensional adaptive filtering (MAF) by determining its effects on image noise and image quality in multi-slice spiral CT (MSCT) of the pelvis., Materials and Methods: Fifty patients with rectal and bladder cancer were examined with MSCT using a high-resolution protocol. Reconstructions were performed with dedicated reconstruction software and a standard algorithm, both without and with MAF, with four different modification fractions selected from 5 % to 20 %. The noise was measured at six anatomic sites of the pelvis. Image quality and image noise were rated on a 5-point-scale., Results: Modification fractions of 15 % (15 % MAF) and 20 % (20 % MAF) significantly reduced the noise level at all measurement points in comparison with lower modification fractions (p < 0.05). Overall quality of the reconstructed images was rated better with 15 % MAF and 20 % MAF than with other modification fractions (p < 0.05). No further improvement of the image quality was observed by changing from 15 % MAF to 20 % MAF (p > 0.05). 15 % MAF achieved a mean noise reduction of 33 %. All examinations showed an improved visualization of the rectal wall and perirectal lymph nodes., Conclusions: MAF improves the image quality by reducing the noise level and by removing noise structures. This technique offers new perspectives to radiation dose reduction in CT.

We report a 57-year-old woman with neuroborreliosis presenting with headache, shoulder muscle pain and double vision. MRI demonstrated enhancement of the right third and sixth cranial nerves. A 3D MP-RAGE sequence was used to perform multiplanar reformations to show this more graphically. The patient was free of symptoms 1 month after completion of therapy, when thickening and contrast enhancement of the nerves were less pronounced.

Purpose: MRI is the most reliable method to differentiate scar and recurrent carcinoma of the breast after surgical treatment. This study compares MRI and color-coded ultrasound with and without echo signal amplifier (ESA)., Materials and Methods: Forty-two patients with suspected recurrent tumors were enrolled in this prospective study, with 38 patients after breast conserving therapy and 4 after mastectomy. All patients had a clinical examination, mammography (n = 38), real time ultrasound (US), color-coded ultrasound without and with ESA (Levovist(R), Schering, Berlin), and dynamic MRI. The criteria used for duplex ultrasound were tumor vascularisation and flow pattern. The results were compared with histologic findings or the results of follow-up examinations for at least 12 months., Results: The detection of penetrating or central vessels proved to be an accurate sign of malignancy in duplex ultrasound. With the application of ESA, additional vessels were detected within the lesions, increasing the diagnostic accuracy (83 % with ESA versus 79 % without ESA). The sensitivity of color-coded ultrasound improved from 64 % to 86 % with echo signal amplifier. The specificity was 86 % without and 82 % with echo signal amplifier. MRI was found to have a sensitivity of 100 % and a specificity of 82 %. The same 5 lesions were false positive on MRI and color-coded US after Levovist(R). No lesion without signs of vascularity within or in its vicinity was malignant., Conclusion: Color-coded ultrasound seems to be a promising method in the differentiation between scar and recurrence. Lesions with penetrating or central vessels have a high probability of being malignant, whereas lesions without any signs of vascularity inside or nearby have a high probability of being benign. Advantage of contrast-enhanced US is its ubiquitous availability.

Purpose: Determination of image quality between conventional film screen system, digital phosphor storage plate mammography (high resolution) and digital mammography., Materials and Methods: Mammograms of the Wisconsin Mammographic Random Phantom, Model 152 A (Radiation Measurements Inc., Wisconsin) were acquired using a conventional film-screen system, a digital storage phosphor plate system and a digital system., Results: Of 225 possible details, 191/a 38.2, 193/a 38.6, and 202/a 40.4 details were detected with conventional film-screen system, digital phosphor storage plate mammography and digital mammography, respectively. There was no significant difference (p < 0,058). The entrance surface air kerma was 9.64 mGy, 7.60 mGy and 7.02 mGy, respectively., Conclusions: Based on these results, conventional film-screen system can be replaced with both digital phosphor storage plate mammography and digital mammography, to be confirmed with further clinical trials.

Purpose: To evaluate a novel multislice CT system (16-slice-spiral-CT scanner) for the diagnosis of carotid artery stenosis., Material and Methods: Five patients with symptomatic atherosclerotic disease of the carotid arteries were examined with a 16- slice-spiral-CT scanner. Collimation was 16 x 0.75 mm, table speed 36 mm/s (pitch of 1.5), rotation time 0.5 s, tube current was 160 eff.mAs at 120 kV. 60 ml of contrast material were injected with a power injector followed by a saline flush. The start delay was measured with test bolus method (20 ml CM). Interactive multiplanar reformation (iMPR) and thin slab MIP as well as volume rendering were used for image evaluation and presentation., Results: Scan time was 9 s for a range of 300 mm. This allowed imaging the whole length of the carotid artery (aortic arch to circle of Willis) in a true arterial phase. Pulsation artefacts did not impair the evaluation of the vessels at the level of the aortic arch. Overall image quality of both "source images" and 3D-reconstructions was excellent, due to a reduced voxel size of 0.03 mm (3). Image evaluation and postprocessing (iMPR, MIP) was done within 15 min. iMPR was highly accurate for demonstrating plaque morphology and determining the percentage of the stenosis., Conclusion: For the first time, true arterial phase images of the entire carotid artery with high spatial resolution could be acquired using a 16-slice-spiral-CT scanner. This method offers the potential to replace catheter angiography in the evaluation of carotid artery stenosis.

Purpose: To examine the diagnostic accuracy of pancreatic lesions using mangafodipir-trisodium (Mn-DPDP) enhanced MR imaging. The imaging results were correlated with the histopathological results., Material and Methods: 40 patients with suspicion of pancreatic carcinoma were examined with MRI before and after i. v. administration of Mn-DPDP (Philips Gyroscan ACS NT 1.5 T, phased array body-coil: TSE T 2 with and without SPIR, TR 2000 ms, TE 120ms; FFE T 1 breathhold, TR 115 ms, TE 4.6 ms; MRCP, TR 6000 ms, TE 1200 ms; Teslascan i. v. 5 micromol Mn/kg; FFE T 1 breathhold SPIR, TR 140 ms, TE 4,6 ms). Two observers evaluated in consensus the number and characteristics of focal pancreatic lesions. The MR findings were correlated with histopathological findings retrospectively., Results: The following lesions were found: adenocarcinoma (19), pancreatitis (8), adenocarcinoma within pancreatitis (3), insulinoma (2), hematoma (1), papillitis stenosans (1), signet ring cell carcinoma (1), metastasis of rectal carcinoma (1), papillary mesothelioma (1). In three patients there was no pathological finding. Mn-DPDP enhanced MRI showed a sensitivity of 100 % and a specificity of 56 %., Conclusion: Mn-DPDP enhanced MRI in conjunction with MRCP showed a high sensitivity for the detection of pancreatic lesions. However, the specificity is low, thus recommending Mn-DPDP enhanced MRI only as a complementary imaging method.