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Abdominal wall hernias are common and can present as technical challenges to surgeons. When large, hernias diminish quality of life. Various classifications of incisional hernias have been proposed; however, there are many terms, sometimes causing confusion (1). Radiologists must know the normal anatomy of the abdominal wall, the CT protocol, and what if any maneuvers can be performed to better identify an abdominal wall defect. The description of the radiological approach for primary and incisional wall hernias is based on the 2007 European Hernia Society classification, with particular emphasis on presurgical and postsurgical imaging findings. This classification provides a simple and reproducible method to describe hernias to offer proper surgical management. We highlight this classification so that radiologists and surgeons can have a unified language.

Objective: The study is aimed at optimizing the existing CT protocol for head scans in a Specialist Teaching Hospital in Edo State with a 16-slice Siemens Somatom Emotion scanner. Also, the study determined the volume computed tomography dose index (CTDIvol) and Dose Length Product (DLP) from the patient's dose profiles. The results from this study were compared with relevant studies. Materials and Methods: The scanner was used to acquire head CT of 160 patients retrospectively. Also, a locally designed head phantom was used to simulate individual patients using a similar protocol by changing the tube current (mA) and total scan width (TSW) only from the existing protocol. Results: Percentage dose reduction (PDR) for the CTDIvol and DLP ranged 42.00-46.80% and 37.13-43.54% respectively. The optimized CTDIvol and DLP were lowest compared to studies in the United Kingdom (UK), Italy, India, Ireland, Sudan, Nigeria, European Commission (EC), United States of America (USA) and Japan. Only the DLP for India was lower than our optimized value. Conclusion: The need to understudy CT configuration is necessary, this will allow end-users to optimize certain parameters in the CT scanner, which will reduce the patient dose without compromising image quality

To investigate the dependence of textural parameters of pancreatic ductal adenocarcinoma on using standard and low-dose CT protocols.Materials and methods. The study included 52 consecutive patients with histologically confirmed pancreatic ductal adenocarcinoma who underwent contrast enhanced computed tomography using standard (120 kV) and low-dose (100 kV) scanning protocols. We compared radiomics features of the identical histological tumors in all scanning phases.Results. We calculated 53 radiomics features in all types of pancreatic ductal adenocarcinoma grade differentiation for all scanning phases. We identified that out of 53 features of texture analysis, less than half was statistically different for each scan phase (11 parameters (20.8%) for the unenhanced phase; 18 parameters (34%) for the arterial; 19 parameters (35.8%) for the venous and delayed scanning phases), in all types of tumor differentiation (GLCM_ Contrast, GLCM_Correlation, GLCM_Dissimilarity, GLRLM_SRHGE etc., p < 0.05).The diagnostic accuracy of more than 50% of the radiomics features is preserved when changing kV in the CT scan protocol.Conclusion. The use of a low-dose CT protocol doesn’t affect the diagnostic accuracy of the features of texture analysis in the preoperative assessment of the degree of differentiation of pancreatic ductal adenocarcinoma.

To evaluate the variability of quantitative measurements of metastatic liver lesions by using a multi-radiation-dose-level and multi-reader comparison. Twenty-three study subjects (mean age, 60 years) with 39 liver lesions who underwent a single-energy dual-source contrast-enhanced staging CT between June 2015 and December 2015 were included. CT data were reconstructed with seven different radiation dose levels (ranging from 25 to 100%) on the basis of a single CT acquisition. Four radiologists independently performed manual tumor measurements and two radiologists performed semi-automated tumor measurements. Interobserver, intraobserver, and interdose sources of variability for longest diameter and volumetric measurements were estimated and compared using Wilcoxon rank-sum tests and intraclass correlation coefficients. Inter- and intraobserver variabilities for manual measurements of the longest diameter were higher compared to semi-automated measurements (p

Multi-societal consensus recommendations endorse both planar and single photon emission tomographic (SPECT) image acquisitions for the evaluation of cardiac amyloidosis. However, the correlation between planar and SPECT findings and the optimal timing of image acquisitions remain uncertain. This is an analysis of 109 consecutive patients who underwent technetium pyrophosphate nuclear scintigraphy for the evaluation of cardiac amyloidosis. Patients were imaged at 1 and 3 hours after radiotracer injection using both planar and SPECT/CT, and the correlations between imaging protocols were compared. In the overall cohort (median age 77 years, 75% male), 33 patients had radiotracer localized to the myocardium on SPECT/CT images. There was strong correlation between 1- and 3-hour planar heart-to-contralateral lung ratios (mean difference 0.07, r = 0.94). However, there was discordance between planar image interpretation (based upon semiquantitative score and H/CL ratio) and myocardial localization of radiotracer on SPECT/CT in 17 patients (16%). The pattern of SPECT/CT uptake was identical at 1 and 3 hours in all cases (32 diffuse, 1 focal). These data support the recommendation that SPECT/CT should be obtained in addition to planar images when performing nuclear scintigraphy for the detection of cardiac amyloidosis. A 1-hour planar and SPECT/CT protocol appears optimal.

We present the appearance of chordae tendineae calcification on transthoracic echocardiography and ECG-gated cardiac computed tomography in a 75 year-old woman. While the etiology is unclear, the abnormality can be clearly delineated on a properly performed CT study. We also discuss modification of the cardiac CT protocol to optimize visualization of the tricuspid valve apparatus. Keywords: Chordae tendineae, Calcification, Tricuspid valve, Echocardiography, Computed tomography

The purpose of this study is to examine radiation doses and image quality of a low-dose (LD) protocol for chest and abdomen/pelvis (CAP) CT compared with a standard (STD) protocol. A total of 361 patients were included between October 2019 and April 2020; 104 patients with LD-protocol (100 kV, ref mAs 80 (chest)/145 (abdomen/pelvis)) and 257 patients with STD-protocol (100 kV, ref mAs 100 (chest)/180 (abdomen/pelvis)) at second-generation dual-source CT. Radiation doses for CTDIvol and DLP, and objective and subjective image qualities of 50 examinations from each group were evaluated. The LD-protocol applied significantly lower radiation doses compared with the STD-protocol (p

In the literature, no consensus exists about which CT protocol is to be adopted in patients who underwent high-energy blunt trauma. The aim of the study is to evaluate the additional value of the arterial phase in the CT assessment of vascular injuries of the liver. Admission CT examinations for patients with traumatic injury of the liver due to high-energy blunt trauma, performed between 2011 and 2017 in two major trauma centres, were retrospectively reviewed. Images were analysed for presence or absence of liver parenchymal injury, intrahepatic contained vascular injuries and active bleeding in the arterial and portal venous phase of the CT study. Two hundred twelve patients have been identified. Parenchymal injuries were detected as isolated in 90.6% of cases, whereas they were associated with vascular injuries in 9.4% of cases: contained vascular injuries in 3.3% and active bleeding in 6.1%. Out of all parenchymal injuries detected on the CT portal venous phase, 90.5% were also detectable in the arterial phases (p

Purpose Acute mesenteric ischemia (AMI) may be underdiagnosed when not clinically suspected before CT is performed. We assessed the influence of a clinical suspicion of AMI on the CT accuracy. Method This retrospective single-centre study included patients who underwent CT in 2014–2019 and had clinically suspected AMI and/or confirmed AMI. CT protocols were adapted based on each patient’s presentation and on findings from unenhanced images. The CT protocol was considered optimal for AMI when it included arterial and portal venous phases. CT protocols, accuracy of reports, and outcomes were compared between the groups with and without suspected AMI before CT. Results Of the 375 events, 337 (90 %) were suspected AMI and 66 (18 %) were AMI, including 28 (42 %) with and 38 without suspected AMI. These two groups did not differ significantly regarding the medical history, clinical presentation, or laboratory tests. The CT protocol was more often optimal for AMI in the group with suspected AMI (26/28 [93 %] vs. 28/38 [74 %], p = 0.046). Diagnostic accuracy was not different between groups with and without suspected AMI (26/28 [93 %] vs. 34/38 [90 %], p = 1.00). However, it was lower in the group without suspicion of AMI when the CT protocol was not optimal for AMI (27/28 [96 %] vs 7/10 [70 %], p = 0.048). Conclusions The negative influence of not clinically suspecting AMI can be mitigated by using a tailored CT protocol.

Because of availability and low radiation dose level, low dose computed tomography (CT) is now commonly used to identify illicit in corpore drug transportation. This review illustrates the most common CT findings of in corpore drug transportation and describes complications due to in corpore drug transportation, with a special emphasis on low dose CT. Major information such as number of packets, exact location and aspect of packets must be assessed. Radiologist must be aware of the imaging characteristics of "in corpore" illicit drug transportation, and should know situations that may alter drug smugglers management.

CT has been an integral part of hybrid imaging PET/CT and SPECT/CT for almost two decades and has not received the attention it deserves when compared to PET or SPECT. As the sensitivity and reconstruction of a PET scanner were improved over the years, the amount of radiation from the injected 18F-FDG dose to the patient was decreased and the radiation dose of CT often times superseded the radiation from the injected 18F-FDG dose. Today, many clinics may have a larger portion of radiation dose from CT than from 18F-FDG in a PET/CT scan if they use the vendor’s default CT protocol. Understanding CT can help lower the radiation exposure of CT, and can help improve localization and quantitation of functional PET or SPECT imaging. This chapter covers the essential knowledge of CT to excel the applications of PET/CT and SPECT/CT.

Background Femoral cannulation for extracorporeal circulation (ECC) is a standard procedure for minimally invasive cardiac surgery (MICS) of the atrio-ventricular valves. Vascular pathologies may cause serious complications. Preoperative computed tomography-angiography (CT-A) of the aorta, axillary and iliac arteries was implemented at our department. Methods Between July 2017 and December 2018 all MICS were retrospectively reviewed (n = 143), and divided into 3 groups. Results In patients without CT (n = 45, 31.5%) ECC was applied via femoral arteries (91.1% right, 8.9% left). Vascular related complications (dissection, stroke, coronary and visceral ischemia, related in-hospital death) occurred in 3 patients (6.7%). In patients with non-contrast CT (n = 35, 24.5%) only femoral cannulation was applied (94.3% right) with complications in 4 patients (11.4%). CT-angiography (n = 63, 44.1%) identified 12 patients (19.0%) with vulnerable plaques, 7 patients (11.1%) with kinking of iliac vessels, 41 patients (65.1%) with multiple calcified plaques and 5 patients (7.9%) with small femoral artery diameter (d ≤ 6 mm). In 7 patients (11.1%) pathologic findings led to alternative cannulation via right axillary artery, additional 4 patients (6.3%) were cannulated via left femoral artery. Only 2 patients (3.2%) suffered from complications. Conclusions CT-A identifies vascular pathologies otherwise undetectable in routine preoperative preparation. A standardized imaging protocol may help to customize the operative strategy.

Patients suspected of having an acute aortic syndrome in the ED typically undergo CT of the chest/abdomen/pelvis. However, the overwhelming majority of these exams are negative. With the help of clinical decision support, we implemented a new radiologist monitored ‘aortic dissection screening protocol’ that forgoes routine abdominopelvic imaging in order to reduce radiation dose without compromising diagnostic accuracy. The purpose of the present study is to assess the performance of this protocol. A retrospective analysis was performed to study the effect of the dissection screening protocol on the diagnostic yield, radiation and contrast dose on a total of 835 ED patients who underwent CT scans for suspected aortic dissection over a 48-week study period immediately before and after implementation of the protocol. 3.4% (28/835) of examinations were positive for an acute aortic syndrome over the 48-week study period with no difference in positivity before and after implementation of the ‘aortic dissection screening’ protocol, 3.0% vs. 3.7%, respectively (p = 0.57). There was a 14.6% reduction in median radiation dose and a 16% decrease in contrast volume utilization for the total ED population who underwent CT for aortic dissection using any protocol in the period after implementation of the ‘aortic dissection screening’ protocol. Aortic dissection CT in the ED is negative in the overwhelming majority of cases. A monitored ‘aortic dissection screening’ protocol that initially images the chest only significantly reduced contrast and radiation dose without reducing diagnostic accuracy for ED patients who underwent CT for aortic dissection.

This study assessed radiation dose after CT-guided percutaneous radiofrequency ablations (RFAs) of hepatic and renal tumors and the effect of weight-based CT protocol modification for lowering overall dose in these procedures.CT-guided RFA for renal and hepatic ablations performed from January 1, 2009, through December 31, 2009, were retrospectively reviewed (90 men and 48 women; age, 42-81 years). The radiation dose was recorded during each of the following steps: planning, performing, and postprocedure. Weight-based protocol modification changes in tube voltage and tube current were then applied to renal and hepatic ablations performed subsequently (18 men and 11 women; age, 48-82 years). Image quality, needle localization, lesion detection, ability to detect complications, and overall operator satisfaction were noted for each case (score, 1-5). Dose reduction after modification was then calculated.Retrospective analysis found a mean (± SD) overall CT dose index (CTDI) for CT-guided RFA to be 16.5 ± 2.3 mGy. After protocol modification, the mean CTDI decreased to 6.63 ± 0.67 mGy, a 59.6% reduction overall; for hepatic ablations, the reduction was 65.96% (p0.0001) and the reduction for renal ablations was 38.97% (p = 0.0153). Image quality analysis showed high operator satisfaction (3-5), including adequate needle localization (4-5), lesion visibility (3-5), and high performer confidence (4-5). Higher dose reduction was noted for patients weighing more than 180 lb (82 kg) (p0.0001).Simple weight-based CT protocol modifications can significantly reduce radiation dose during CT-guided percutaneous ablations in the liver and kidneys without significantly sacrificing image quality.

Children with congenital heart diseases (CHDs) may need to be followed up with contrast-enhanced CT following the Fontan operation because complications such as the occlusion of conduits may occur. The purpose of the present study was to develop an adequate contrast-enhanced CT protocol for children with CHD following the Fontan operation. Between July 2012 and July 2017, 29 CT examinations for 26 patients aged 2–11 years (median 5 years) with CHD following the Fontan operation were performed using dual-source CT. A non-ionized contrast medium was injected through the dorsum manus vein. Scanning began 60 or 70 s after the start of the injection. The delayed phase was randomly selected to be 60 s in 14 cases and 70 s in 15 cases. We evaluated the enhancement of conduits following the Fontan operation at delayed phases. The CT numbers of conduits at 60 and 70 s were 185 ± 46 and 185 ± 31 HU, respectively (P = 0.97). In contrast-enhanced CT for children after the Fontan operation, both of the delayed phases (60 and 70 s) appeared to be adequate for evaluating intraconduit patency.

Background Cardioembolic factors are responsible for 20–30% of ischemic strokes, especially atrial fibrillation (AF) through left atrial appendage (LAA) thrombus formation. The aim of the present study was to evaluate the prevalence and associated factors of LAA thrombus (LAAt) in patients with acute ischemic stroke by adding a cardiac CT during the initial imaging, and their early management and outcome accordingly. Methods From November 2018 to October 2019, 875 consecutive patients admitted with stroke like symptoms in the emergency department of our institution were included. All patients underwent a stroke CT protocol including a non-enhanced brain CT, a brain perfusion if necessary, a carotid CT angiography, a cardiac CT and a post-contrast brain CT. The cardiac CT was performed with a prospectively ECG gated volume acquisition. Results Among 324 strokes confirmed, 35 LAAt patients (11%) and 289 no LAAt patients were analysed. Compared to no LAAt patients, LAAt patients were significantly older (82 ± 12 vs. 74 ± 14 years old, P = 0.002), predominantly female (71% vs. 45%, P = 0.004) and more often had previous AF history (63% vs. 15%, P Conclusion This study highlights the contribution of cardiac CT, in addition to the usual brain CT in acute stroke imaging protocol in routine practice, for LAA thrombus evaluation. Such a strategy could be helpful for making decision with regard to early anticoagulation initiation. Further studies are needed to assess the impact on patients’ outcome.

Purpose To present our experience in reducing CT radiation doses in a complex tertiary health system through CT protocol standardization and optimization. Methods A CT radiation task force was created to reduce CT protocol heterogeneity and radiation doses. Redundant protocols were eliminated. By an iterative process, protocols with least radiation dose were identified. Radiation dose tracking software was used to store and analyze radiation doses. CT protocols were published in an intranet site after training of technologists. SOPs were established for maintaining and changing protocols. The radiation doses for each CT protocol before and after optimization were compared using geometric means. Results A total of 222 CT protocols were reviewed, with elimination of 86 protocols. One-year follow-up showed homogeneous protocols with lower radiation doses. The improvement in radiation doses ranged from 23% to 58% (P Conclusion CT radiation dose reduction of up to 58% can be achieved by homogenizing and optimizing CT protocols through a comprehensive CT operations program.

Most imaging centers have more than one make and model of CT scanner in use across multiple locations within a hospital, city, or geographical region. These different scanners must fulfill identical imaging requests while often simultaneously realizing local site-specific exams. Many sites have in the hundreds of CT protocols to satisfy the hundreds of order sets a clinical diagnostic CT scanner receives. These clinical and logistical realities make CT protocol management challenging. This chapter defines this problem in more detail. We discuss strategies to address CT protocol management. We define a CT protocol from the perspective of clinical, compliance, workflow, and technical details. We discuss why we need a CT protocol optimization team and team membership. Lastly, we review solutions for documenting CT protocols and disseminating them to one’s CT scanner fleet.

Based on the clinical perspective, the three essential elements of CT practice optimization are appropriate clinical indications for the CT scan, CT protocol design based on a team-based approach, and adjustments of scan parameters according to patient size, body region, and clinical indication. Dose monitoring can identify CT protocols with excessive doses that need attention and modifications. Active surveillance strategies ensure a good diagnostic quality of performed CT examinations while adhering to the ALARA (as low as reasonably achievable) principle for radiation doses.

Purpose To determine if a reduced-dose computed tomography (CT) protocol could effectively help to identify patients in the emergency department (ED) with moderate to high likelihood of calculi who would require urologic intervention within 90 days. Materials and Methods The study was approved by the institutional review board and written informed consent with HIPAA authorization was obtained. This was a prospective, single-center study of patients in the ED with moderate to high likelihood of ureteral stone undergoing CT imaging. Objective likelihood of ureteral stone was determined by using the previously derived and validated STONE clinical prediction rule, which includes five elements: sex, timing, origin, nausea, and erythrocytes. All patients with high STONE score (STONE score, 10-13) underwent reduced-dose CT, while those with moderate likelihood of ureteral stone (moderate STONE score, 6-9) underwent reduced-dose CT or standard CT based on clinician discretion. Patients were followed to 90 days after initial imaging for clinical course and for the primary outcome of any intervention. Statistics are primarily descriptive and are reported as percentages, sensitivities, and specificities with 95% confidence intervals. Results There were 264 participants enrolled and 165 reduced-dose CTs performed; of these participants, 108 underwent reduced-dose CT alone with complete follow-up. Overall, 46 of 264 (17.4%) of patients underwent urologic intervention, and 25 of 108 (23.1%) patients who underwent reduced-dose CT underwent a urologic intervention; all were correctly diagnosed on the clinical report of the reduced-dose CT (sensitivity, 100%; 95% confidence interval: 86.7%, 100%). The average dose-length product for all standard-dose CTs was 857 mGy · cm ± 395 compared with 101 mGy · cm ± 39 for all reduced-dose CTs (average dose reduction, 88.2%). There were five interventions for nonurologic causes, three of which were urgent and none of which were missed when reduced-dose CT was performed. Conclusion A CT protocol with over 85% dose reduction can be used in patients with moderate to high likelihood of ureteral stone to safely and effectively identify patients in the ED who will require urologic intervention. (©) RSNA, 2016 Online supplemental material is available for this article.

PurposeThe purpose of this study was to determine the frequency in which the pelvis component of an abdominopelvic CT provides information that would influence clinical management in two separate groups of patients: those with previously resected pancreatic ductal adenocarcinoma (PDA) and those with locally advanced unresectable PDA.MethodsThis institutional review-board approved HIPAA compliant retrospective study with waived informed consent included 247 subjects with histologically proven PDA, including 153 subjects post-pancreaticoduodenectomy and 94 subjects with locally advanced unresectable disease. Imaging reports interpreted between January 2005 and December 2013 were obtained from our institution's Radiology Information System by searching a Cancer Registry database of PDA patients separately for the words "whipple" and "unresectable." CT findings were separated by location in the abdomen or pelvis, and subsequently reviewed and graded for their likelihood of representing metastatic disease. The probability of pelvic CT influencing clinical management-i.e., of finding isolated pelvic metastatic disease-was determined using 95% binomial proportion confidence intervals for both the post-pancreaticoduodenectomy and locally advanced unresectable groups.ResultsNo subjects who had undergone pancreaticoduodenectomy had an isolated pelvic metastasis on follow-up imaging (0%; 95% CI 0-2.38, p=0.0004); 33 had metastatic disease in the abdomen, and 120 had no or equivocal evidence of abdominopelvic metastatic disease. One subject with locally advanced unresectable PDA had a possible isolated pelvic metastasis on follow-up imaging (1.1%; 95% CI 0.03-5.79, p=0.048); 20 had metastatic disease in the abdomen, and 73 had no or equivocal evidence of abdominopelvic metastatic disease.ConclusionIsolated pelvic metastatic disease rarely occurs in patients with PDA who have had prior pancreaticoduodenectomy or have a locally advanced unresectable primary tumor, suggesting routine pelvic CT in follow-up imaging of these patients may not be necessary.

Aim To improve the practice of trauma computed tomography (CT) within Wales using recognised leadership techniques for change. Materials and methods Royal College of Radiologists' (RCR) guidance, in addition to other key recent evidence, were used to form an aspirational standard. All centres across Wales with a major emergency department were included. Kotter's theory of change was utilised to facilitate an improvement in practice across the region, with larger units prioritised initially. Results Of the 13 major emergency units in Wales, eight centres had no formal trauma CT protocol. Only one centre utilised the Bastion protocol (in comparison to 75% of major trauma centres). After the campaign to improve trauma imaging, seven centres now offer the Bastion protocol, with currently only three peripheral centres still without a procedure for whole-body CT. The two largest centres have implemented an emergency department pro forma. Conclusion Trauma CT within Wales has significantly improved as a result of this project. Kotter's theory is demonstrated as an effective tool for facilitating a change in practice on a regional/national scale.

Purpose: Computerized tomography (CT) imaging is increasingly being used to evaluate patients with ankle trauma. However, conventional CT (C CT) has a significantly higher radiation dose (RD) than plain radiography. This study aimed to evaluate the diagnostic accuracy and reliability of ultra-low-dose CT (ULDCT) protocol for ankle fractures. Methods: Ninety-eight consecutive patients who had ankle CT for suspected ankle fracture were included in our prospective study. C CT and ULDCT protocols were simultaneously performed on these 98 patients. Two observers independently evaluated ULDCT and C CT images. The effective RD of the ULDCT and C CT groups was calculated. Results: The interobserver agreement was 1 (perfect). ULDCT and C CT group images showed no significant difference in image quality. The effective RD of the ULDCT was significantly lower than the C CT ( p < 0.001). Conclusions: By evaluating the results of this study, ULDCT proved to be a reliable diagnostic imaging method for fractures of the ankle. The satisfactory diagnostic image quality of the ULDCT protocol provides promising results. Level of Evidence: Level II/lesser quality RCT or prospective comparative study

Objectives The aim of this study is to compare the radiologic diagnostic performance of arterial phase, portal phase and combined phase computed tomography (CT) for traumatic abdominal injury. In addition, this study is attempted to decrease lifetime attributable risks (LARs) of cancer due to radiation exposure by using optimal CT protocol. Materials and methods A total of 114 consecutive patients with a traumatic abdominal injury and an abdominal hematoma on CT were enrolled at a single tertiary regional trauma center between January 2016 and March 2017. Each CT protocol set was independently reviewed by three radiologists, and the diagnostic performance of all three CT phases were compared with regard to the capability to detect active bleeding, contained vascular injuries, and organ injuries. Additionally, LARs for cancer incidence and mortality were calculated using dose-length product values, for each phase of CT. Results The pooled area under the receiver operating characteristic curves for the diagnosis of active bleeding, contained vascular injuries, and organ injuries ranged from 0.910 to 0.922, 0.643 to 0.723, and 0.948 to 0.915 for arterial, portal, and combined phase CT, respectively. There was no statistically significant difference in the diagnosis of active bleeding and organ injuries for any combination of two phase sets. The mean LARs for cancer incidence was 0.059%, 0.062% and 0.121% during arterial, portal and combined phase CT, respectively. Conclusion Single phase CT could be a potential protocol for abdominal trauma patients. Use of single phase CT could significantly decrease the incidence of radiation-associated cancer in the future.

Low dose ionising radiation such as from CT scans carries a low but cumulative risk of cancer and children are particularly sensitive. Children with VP Shunts often undergo multiple CT scans. We developed a CT protocol with reduced radiation for paediatric patients with shunts and compared it with the current practice in the other neurosurgical units in the UK and ROI by conducting a nationwide survey.An email questionnaire was send to the superintendent radiographer in every Neurosurgical unit in the UK and the ROI.The response rate was 70%. Only 5 (19%) of the responding units used a dedicated CT shunt protocol with reduced radiation. Radiation was reduced by lowering the tube current. In comparison, our protocol uses a combination of less tube current and fewer slices. This reduced the radiation exposure of a CT head significantly with sufficient image quality to make a diagnosis.Radiation from CT for paediatric shunt patients scans can and should be reduced. This can be achieved by using reduced radiation protocols. A national paediatric CT shunt protocol could lead to significant reduction in effective radiation dose.

The current study compared the impact of low radiation CT protocols on the accuracy, repeatability, and inter- and intra-observer variability of implant migration studies in total hip arthroplasty. Two total hip replacements were performed in two human cadavers and six tantalum beads were inserted into the femur similar to radiostereometric analysis. Six different 28 mm heads (-3 mm, 0 mm, 2.5 mm, 5.0 mm, 7.5 mm, and 10 mm) were added to simulate five reproducible translations (maximum total point migration) of the center of the head. Three CT scans with varying levels of radiation were performed for each head position. The effective dose (mSv) was 3.8 mSv for Protocol A (standard protocol), 0.7 mSv for Protocol B and 1.6 mSv for Protocol C. Implant migration was measured in a 3-D analysis software (Geomagic Studio 7). The accuracy was 0.16 mm for CT Protocol A, 0.13 mm for Protocol B and 0.14 mm for Protocol C; The repeatability was 0.22 mm for CT Protocol A, 0.18 mm for Protocol B and 0.20 mm for Protocol C; ICC for inter observer reliability was 0.89, intra observer reliability was 0.95. The difference in accuracy between standard protocol A and the two low radiation protocols (B, C) was less than 0.05 mm. The accuracy, inter- and intra-observer reliability of all three CT protocols is comparable to radiostereometric analysis. Reducing the CT radiation exposure to numbers similar to an AP Pelvis radiograph (0.7 mSv protocol B) does not affect the accuracy of implant migration measurements.

This prospective study compared a 1-d SPECT/CT protocol with the commonly used 3-d protocol for somatostatin receptor scintigraphy in patients with gastroenteropancreatic neuroendocrine neoplasms. Additionally, the influence of SPECT/CT on patient management was evaluated. Methods: From October 2011 to October 2012, all gastroenteropancreatic neuroendocrine neoplasm patients undergoing restaging with somatostatin receptor scintigraphy on a modern SPECT/CT device were enrolled in this study. The protocol consisted of planar imaging at 4, 24, and 48 h; low-dose SPECT/CT at 24 and 48 h; diagnostic CT at 24 h using a triple-phase delay after administration of contrast; and diagnostic SPECT/CT at 24 h. All components of the imaging data were reassessed by 3 masked interpreters. The results were compared with a reference standard based on all clinical, imaging, and histopathology follow-up data available (follow-up range, 24–36 mo; mean, 29.9 mo). The reference standard was defined by a study-specific interdisciplinary tumor board that also reassessed treatment decisions. Results: Thirty-one patients were eligible for analysis (18 men and 13 women; mean age, 60.4 y). Ten had no imaging signs of disease and remained disease-free during follow-up. Twenty-one had persistent or recurrent disease (82 lesions: 24 in the liver, 21 in the lymph nodes, 16 in bone, 12 in the pancreas, and 9 in other locations). The respective lesion detection rates for interpreters 1, 2, and 3 were 51.9%, 49.4%, and 71.6% for low-dose SPECT/CT at 24 h; 51.9%, 55.6%, and 67.9% for low-dose SPECT/CT at 48 h; 63.0%, 70.4%, and 85.2% for diagnostic CT; and 77.8%, 84.0%, and 88.9% for diagnostic SPECT/CT. Interobserver agreement was moderate for diagnostic SPECT/CT (κ = 0.44), diagnostic CT (κ = 0.43), low-dose SPECT/CT at 48 h (κ = 0.61), and low-dose SPECT/CT at 24 h (κ = 0.55). For planar imaging, interobserver agreement was fair after 48 h (κ = 0.36) and 24 h (κ = 0.38) and moderate after 4 h (κ = 0.42). Every lesion detectable on planar imaging or low-dose SPECT/CT was also detectable on diagnostic SPECT/CT. The CT and SPECT components of diagnostic SPECT/CT strongly complemented each other, as 34 of 82 lesions (41.4%) were detected on only the CT component or only the SPECT component. Therapeutic management was influenced by the diagnostic SPECT/CT interpretation in 8 of 31 patients (25.8%). Conclusion: The highest detection rates were achieved by diagnostic SPECT/CT. Thus, a more patient-friendly 1-d protocol is feasible. Furthermore, multiphase SPECT/CT affected management in about a quarter of patients.

Aim To quantify the dose reduction and ensure that the use of a split-bolus protocol provided sufficient vascular enhancement. Materials and methods Between 1 January 2014 and 31 May 2014, both split bolus and traditional two-phase scans were performed on a single CT scanner (SOMATOM Definition AS+, Siemens Healthcare) using a two-pump injector (Medrad Stellant). Both protocols used Siemens' proprietary tube current and tube voltage modulation techniques (CARE dose and CARE kV). The protocols were compared retrospectively to assess the dose–length product (DLP), aortic radiodensity at the level of the coeliac axis and radiodensity of the portal vein. Results There were 151 trauma CT examinations during this period. Seventy-eight used the split-bolus protocol. Seventy-one had traditional two-phase imaging. One patient was excluded as they were under the age of 18 years. The radiodensity measurements for the portal vein were significantly higher ( p 0.001) in the split-bolus protocol. The mean aortic enhancement in both protocols exceeded 250 HU, although the traditional two-phase protocol gave greater arterial enhancement ( p 0.001) than the split-bolus protocol. The split-bolus protocol had a significantly lower ( p 0.001) DLP with 43.5% reduction in the mean DLP compared to the traditional protocol. Conclusion Split-bolus CT imaging offers significant dose reduction for this relatively young population while retaining both arterial and venous enhancement.

To sustain compliance with accreditation requirements of the ACR, Joint Commission, and state-specific statutes and regulatory requirements, a CT protocol review committee requires a structure for systematic analysis of protocols. Safe and reproducible practice of CT in a complex environment requires that physician supervision processes and protocols be precisely and clearly presented. This article discusses necessary components for data structure, and a description of an IT-based approach for protocol review based on experiences at 2 academic centers, 3 community hospitals, 1 cancer center, and 2 outpatient clinics.

Backgroud: In Radiology Installation of Gading Pluit Jakarta Hospital, CT Scan of the ankle joint uses abdomen CT protocol because it produces image quality that is considered to be able to diagnose and provide adequate information, although in Gading Pluit Jakarta Hospital there is a choice of CT protocol with Ultra High Resolution (UHR). The purpose of this study was to determine the difference of anatomical information on ankle joint CT scan between abdomen CT protocol and ankle joint CT protocol at Gading Pluit Jakarta Hospital and which protocol is better between UHR ankle protocol and abdomen protocol.Methods: This type of this research was an experimental study. The study was conducted by performing two times of scanning with different protocols such as abdomen protocol and ankle joint protocol on ankle joint CT scan examination. The image was assessed by seven radiology physicians by viewing the information of the image. Data were analyzed statistically with Wilcoxon test.Results: The results of this study showed that there was significant difference between abdomen protocol and UHR ankle joint protocol, with Wilcoxon p.value = 0,00 (p 0,05) and on ankle joint CT Scan examination, UHR ankle joint protocol was better than abdomen protocol so that the UHR ankle protocol was well applied in daily examination on CT scan of ankle joint.Conclusion: There was difference between the abdomen CT protocol and ankle joint CT protocol (UHR) in Radiology Installation of Gading Pluit Jakarta Hospital. The ankle CT protocol (UHR) was better than the abdomen CT protocol on ankle joint CT scan examination in Radiology Installation of Gading Pluit Jakarta Hospital.

The authors report the implementation and outcomes of a CT radiation dose optimization and tracking program at a large quaternary-care health care system.A committee reviewed, optimized, and released standardized imaging protocols for the most common CT examinations across the health system. Volume CT dose index and dose-length product (DLP) diagnostic reference levels (DRLs) were established, with the goal of decreasing the percentage of outliers (CT scans with DLPs greater than the established DRLs) to5% of tracked CT examinations. Baseline radiation dose data were manually extracted for 5% of total examinations. A semiautomated process to analyze all DLP data was then implemented to monitor outliers.The baseline percentage of outliers was slightly higher than 10% for pediatric scans but nearly 26.5% for adult scans. Over the first year, after standardized protocols were distributed, the percentage of outliers decreased for pediatric brain (from 22% to 6%), adult brain (from 23% to 3%), and adult chest (from 22% to 11%) examinations. Over the next 2 years, after the dose-tracking program was implemented, the percentage of outliers decreased for adult (brain, from 3% to 1%; chest, from 11% to 1%; abdomen, from 24% to 1%) and pediatric (brain, from 6% to 2%; chest, from 11% to 0%; abdomen, from 7% to 1%) examinations.The reported CT protocol optimization and dose-tracking program enabled a sustainable reduction in the proportion of CT examinations being performed above established DRLs from as high as 26% to1% over a period of 2 years.

OBJECTIVE: To retrospectively compare image quality of a lowered dose CT protocol to a standard CT protocol in children with suspicion of craniosynostosis. METHODS: Forty-eight patients (age 0- 35 months), who presented with a cranial deformity underwent cranial 3D CT to assess sutural patency: between 2009 - 2010, 24 patients were imaged with a standard protocol (CTDIvol 32.18 mGy), from 2011-2012, 24 underwent a low dose protocol (0.94 mGy) combined with iterative reconstruction. Image quality was evaluated by both expert reading and objective analysis. Differences were assessed by independent t-test and Mann-Whitney U test, interreader agreement by Cohen's Kappa test. RESULTS: Effective dose of the low dose protocol was 0.08 mSv, corresponding to a reduction of 97 %. Image quality was similar in both groups in terms of overall diagnostic acceptability, objective noise measurements, subjective cranial bone edge sharpness and presence of artefacts. For objective sharpness of cranial bone-brain interface and subjective perception of noise, the images of the low dose protocol were superior. For all evaluated structures, interreader agreement was moderate to almost perfect. CONCLUSION: In the diagnosis of craniosynostosis in children with cranial deformities, a dedicated sub 0.1 mSv cranial 3DCT protocol can be used without loss in image quality. KEY POINTS: • 3DCT is used for the diagnosis of craniosynostosis. • Imaging protocols should be optimized to minimize radiation exposure to children. • Combining 80 kVp with iterative reconstruction can help to reduce dose. • A sub 0.1 mSv cranial 3DCT protocol can be used without loss of diagnostic quality.

OBJECTIVE. The objective of our study was to investigate whether the use of a software-based automated tube potential selection (ATPS) CT neck protocol can result in radiation dose reduction as compared with a set 120-kV protocol without a statistically significant reduction in image quality. MATERIALS AND METHODS. Three hundred sixty-four patients (median age, 52 years) underwent CT of the neck. Group 1 (n = 320) underwent CT with ATPS with 80, 100, or 120 kV. Group 2 (n = 44) was examined with the standard CT protocol at 120 kV. Attenuation, image background noise, signal-to-noise ratio (SNR), dose-length product (DLP), volume CT dose index (CTDIvol), body mass index (BMI [weight in kilograms divided by the square of height in meters]), and subjective image quality (5-point Likert scale, two readers in consensus) were analyzed. RESULTS. A tube potential of 100 kV was selected in 279 patients, 120 kV in 40 patients, and 80 kV in one patient of the ATPS group. A significant correlation was found for selec...

Objective Confirmation whether an optimized clinical cardiac CT scan protocol is also optimal for post mortem cardiac CT scans without iodine contrast or the reconstruction parameters should be changed. Materials and methods 27 CT volumes (three cases for three recon- struction kernel with three different iterative reconstruction settings) were graded by six readers in order to find the optimal reconstruction parame- ters. The scans were performed on a Siemens Definition Flash CT scanner using 120 kV tube potentials. Results The study has shown that from the investigated options the softest cardiac kernel with the strongest iterative reconstruction were pre- ferred by the readers (I26 Safire 3). Conclusion The results indicate that the scan protocol which was adopted from clinical practice is applicable in forensic radiology too even though iodine contrast agent was not administered.

In an effort to decrease door-to-needle times for patients with acute ischemic stroke, some hospitals have begun taking stable EMS patients with suspected stroke directly from the ambulance to the CT scanner, then to an emergency department (ED) bed for evaluation. Minimal data exist regarding the potential for time savings with such a protocol. The study hypothesis was that a direct-to-CT protocol would be associated with decreases in both door-to-CT-ordered and door-to-needle times.An observational, multicenter before/after study was conducted of time/process measures at hospitals that have implemented direct-to-CT protocols for patients transported by EMS with suspected stroke. Participating hospitals submitted data on at least the last 50 "EMS stroke alert" patients before the launch of the direct-to-CT protocol, and at least the first 50 patients after. Time elements studied were arrival at the ED, time the head CT was ordered, and time tPA was started. Data were submitted in blinded fashion (patient and hospital identifiers removed); at the time of data analysis, the lead investigator was unaware of which data came from which hospital. Simple descriptive statistics were used, along with the Mann-Whitney test to compare time medians.Seven hospitals contributed data on 1040 patients (529 "before" and 511 "after"); 512 were male, and 627 had final diagnoses of ischemic stroke, of whom 275 received tPA. The median door-to-CT-ordered time for all patients was 7 minutes in the before phase, and 4 minutes after (difference 3 minutes, p =0.0001); similarly, the median door-to-CT-started time was 6 minutes "before" and 10 minutes after (p0.0001). The median door-to-needle time for all patients given tPA was 42 minutes before, and 44 minutes after (p = 0.78). Four hospitals had modest decreases in door-to-CT-ordered time (of 2, 4, 2, and 5 minutes), and only one hospital had a decrease in door-to-needle time (32 min vs 26 min, p = 0.012).In this sample from seven hospitals, a minimal reduction in door-to-CT-ordered and door-to-CT-started time, but no change in door-to-needle time, was found for EMS patients with suspected stroke taken directly to the CT scanner, compared to those evaluated in the ED prior to CT.

Introducing a hybrid imaging method such as single photon emission computed tomography (SPECT)/CT greatly alters the routine in the nuclear medicine department. It requires designing new workflow processes and the revision of original scheduling process and imaging protocols. In addition, the imaging protocol should be adapted for each individual patient, so that performing CT is fully justified and the CT procedure is fully tailored to address the clinical issue. Such refinements often occur before the procedure is started but may be required at some intermediate stage of the procedure. Furthermore, SPECT/CT leads in many instances to a new partnership with the radiology department. This article presents practical advice and highlights the key clinical elements which need to be considered to help understand the workflow process of SPECT/CT and optimise imaging protocols. The workflow process using SPECT/CT is complex in particular because of its bimodal character, the large spectrum of stakeholders, the multiplicity of their activities at various time points and the need for real-time decision-making. With help from analytical tools developed for quality assessment, the workflow process using SPECT/CT may be separated into related, but independent steps, each with its specific human and material resources to use as inputs or outputs. This helps identify factors that could contribute to failure in routine clinical practice. At each step of the process, practical aspects to optimise imaging procedure and protocols are developed. A decision-making algorithm for justifying each CT indication as well as the appropriateness of each CT protocol is the cornerstone of routine clinical practice using SPECT/CT. In conclusion, implementing hybrid SPECT/CT imaging requires new ways of working. It is highly rewarding from a clinical perspective, but it also proves to be a daily challenge in terms of management.

Technical data on local CT practice in Western Australia were collected for five major CT providers using a self-completed questionnaire. The CTDIvol DLP and effective dose for each protocol were obtained and providers were ranked according to radiation burden for each clinical scenario. The mean, median, 75th percentile and standard deviation were calculated for both effective dose and DLP for each scenario and these values were compared with published data. CT utilisation data were used to estimate the attributable radiation dose to the WA population and the potential change in population annual effective dose according to the protocol used was estimated. We found that wide variations in technique and radiation dose exist across providers for similar examinations, producing a higher radiation burden than reported internationally. As expected, the CT protocol used dramatically affects the radiation dose received, and this has a significant effect on annual population dose. This study highlights the need for recognition and understanding of both the degree of variation in radiation dose across providers and the relatively high radiation burden afforded by protocols in use in Western Australia so that necessary dialogue can be launched for practitioner consensus on appropriate diagnostic reference levels in CT scanning.

To assess the ability of low-dose CT to detect and characterize the most common CT patterns of pulmonary disease.Sixty patients with nodules, consolidations or interstitial disease were scanned using a low-dose (128 mm × 0.6 mm, 40 reference mAs, 120 kVp) and standard-dose CT protocol (150 reference mAs, 120 kVp). Two radiologists with 3 and 10 years of thoracic imaging experience searched both exams in consensus for the most commonly observed CT patterns according to the Fleischner Society criteria, which consisted of 46 different subgroups of ground-glass opacities, nodules, interstitial and airspace diseases. The standard of reference was established by consensus of a panel of two experienced chest radiologists (9 and 12 years of experience).The lung segments (1080) showed 813 nodules, 596 ground-glass opacities, 74 airspace and 575 interstitial diseases and 64 normal segments. In particular, air-space disease and nodules were unaffected by the increase in noise. However, the sensitivity to detect ground-glass opacities, ground-glass nodules and interstitial opacities decreased significantly, from 89% to 77%, 86% to 68% and 91% to 71%, respectively (all p-values0.00001). Using iterative reconstruction instead of the applied filtered back projection sensitivity for ground-glass nodules rose to the sensitivity of standard-dose CT in an additional phantom study.A low-dose CT of 40 mAs/120 kVp is feasible for detecting solid nodules, airspace, airways and pleural disease. For diagnosing pathologies consisting of ground-glass opacities or interstitial opacities, higher tube current or iterative reconstruction is required.

Pediatric abdominal CT has become much rarer during the past decade due to radiation issues. However, it remains a powerful imaging tool indicated in some specific indications such as trauma or as a problem-solving tool. Dedicated pediatric CT protocols are used to reduce radiation burden, and usually a single-phase acquisition is diagnostically sufficient. These radiation issues are discussed in this chapter, technical aspects and tips on how to optimize the CT protocol for pediatric needs are addressed, and the typical indications are listed and some relevant findings demonstrated.

Purpose Computed tomography (CT) examinations, often using high-radiation dosages, are increasingly used in the acute management of polytrauma patients. This study compares a low-dose polytrauma multi-phase whole-body CT (WBCT) protocol on a latest generation of 16-cm detector 258-slice multi-detector CT (MDCT) scanner with advanced dose reduction techniques to a single-phase polytrauma WBCT protocol on a 64-slice MDCT scanner. Methods Between March and September 2015, 109 polytrauma patients (group A) underwent acute WBCT with a low-dose multi-phase WBCT protocol on a 258-slice MDCT whereas 110 polytrauma patients (group B) underwent single-phase trauma CT on a 64-slice MDCT. The diagnostic accuracy to trauma-related injuries, radiation dose, quantitative and semiquantitative image quality parameters, subjective image quality scorings, and workflow time parameters were compared. Results In group A, statistically significantly more arterial injuries (p = 0.04) and arterial dissections (p = 0.002) were detected. In group A, the mean (±SD) dose length product value was 1681 ± 183 mGy*cm and markedly lower when compared to group B (p

Background Triple rule-out computed tomography (TRO CT) is a CT protocol designed to simultaneously evaluate the coronary, aorta, and pulmonary arteries. Purpose To evaluate potential diagnostic performance of TRO CT with restricted volume coverage for detection of pulmonary thromboembolism (PTE) and aortic dissection (AD). Material and Methods This study included 1224 consecutive patients with acute chest pain who visited the emergency department and underwent TRO CT using a 128-slice dual-source CT. Image data were reconstructed according to the display field of view (DFOV) of coronary CT angiography (CCTA) and TRO CT protocols in each patient. The presence of PTE and AD was evaluated by independent observers in each DFOV. The radiation dose was calculated to evaluate the potential benefits by restricting z-axis coverage to cardiac scan range instead of the whole thorax. Results Among all patients, 22 cases with PTE (1.9%) and nine cases with AD (0.8%) were found. Except for one PTE case, all cases were detected on both DFOV of TRO CT and CCTA. Mean effective dose for evaluation of entire thorax and cardiac scan coverage were 5.9 ± 1.1 mSv and 3.5 ± 0.7 mSv, respectively. Conclusion Isolated PTE and AD outside the CCTA DFOV rarely occur. Therefore, modified TRO CT protocol using cardiac scan coverage can be adopted to detect PTE and AD with reduced radiation dose.

Purpose Quantification of the frequency, understanding the motivation, and documentation of the changes made by CT technologists at scan time are important components of monitoring a quality CT workflow. Methods CT scan acquisition data were collected from one CT scanner for a period of 1 year. The data included all relevant acquisition parameters needed to define the technical side of a CT protocol. An algorithm was created to sort these data in groups of irradiation events with the same combinations of scan acquisition parameters. For scans modified at scan time, it was hypothesized that these examinations would show up only once in the organized data. A classification scheme was developed to place each "one-off" examination into a category related to what motivated the scan-time change. Results A total of 132,707 irradiation events were organized into 434 groups of unique scan acquisition parameters. One hundred forty-four irradiation events had acquisition parameters that showed up only once in the data. These "one-offs" were classified as follows: 25% represented rarely used protocols, 17% were due to service scans, 16% were changed for unknown and therefore undesired reasons, 15% were changed by technologists trying to adapt protocol to patient size, 12% were allowable scan-time changes, 8% of scans had tube current maxed out, and 6% of scans were changed to a higher dose mode as requested by radiologists. Conclusions The outcome of this study suggests many areas of needed technologist training and chances for optimizing this institution's CT protocols.

To determine the adequacy of the split-bolus computed tomography (CT) technique in terms of vascular enhancement and solid-organ injury assessment in paediatric trauma.A retrospective review was undertaken of all split-bolus trauma CT examinations performed in patients16 years during the period from 1 January 2015 to 31 January 2016. Twelve examinations were performed in this time on patients with an age range of 2-15 years (mean 10.8) consisting of eight male and four female patients. Abdominal aortic and portal vein attenuation were measured using a region of interest tool.The mean aortic attenuation was 267 HU and mean portal vein attenuation was 203 HU. Five cases of solid-organ injury were detected and the image quality was sufficient to grade the injury and guide clinical management in all cases.Although the cohort is relatively small, good arterial and portal venous enhancement were achieved in all but one patient, where there was suboptimal portal venous opacification; however, there were no other patients in the same weight group making it difficult to determine whether this was a systematic problem or due to patient factors. Overall, these findings have reassured us locally that the current protocol should continue to be used, but the performance of the protocol will be audited continually.