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Background: If tibiofibular syndesmotic injury is undetected, chronic instability may lead to persistent pain and osteoarthritis. So far, no reliable diagnostic method has been available. The primary objectives of this study were to determine whether defined lesions of the syndesmosis can be correlated with specific tibiofibular joint displacements caused by external rotational torque and to compare the performance of bilateral external torque computed tomography (BET-CT) and arthroscopy. Secondary objectives included an evaluation of the reliability of CT measurements and the suitability of the healthy contralateral ankle as a reference., Methods: Seven pairs of healthy, cadaveric lower legs were tested and assigned to 2 groups: (1) supination-external rotation (SER) and (2) pronation-external rotation (PER). In the intact state and after each surgical step, an ankle arthroscopy and 3 CT scans were performed. During the scans, the specimens were placed in an external torque device with 2.5, 5.0, and 7.5 Nm of torque applied., Results: The arthroscopic and CT parameters showed significant correlations in all pairwise comparisons. The receiver operating characteristic (ROC) curve analyses yielded the best prediction of syndesmotic instability with the anterior tibiofibular distance on CT, with a sensitivity of 84.1% and a specificity of 95.2% (area under the curve [AUC], 94.8%; 95% confidence interval [CI], 0.916 to 0.979; p < 0.0001) and with the middle tibiofibular distance on arthroscopy, with a sensitivity of 76.2% and specificity of 92.3% (AUC, 91.2%; 95% CI, 0.837 to 0.987; p < 0.0001). Higher torque amounts increased the rate of true-positive results., Conclusions: BET-CT reliably detects experimental syndesmotic rotational instability, compared with the healthy side, with greater sensitivity and similar specificity compared with the arthroscopic lateral hook test. Translation of these experimental findings to clinical practice remains to be established., Level of Evidence: Diagnostic Level III . See Instructions for Authors for a complete description of levels of evidence., Competing Interests: Disclosure: No external funding was received for this work. The Disclosure of Potential Conflicts of Interest forms are provided with the online version of the article ( http://links.lww.com/JBJS/H853 )., (Copyright © 2024 by The Journal of Bone and Joint Surgery, Incorporated.)

Clinical Issue: The mean number of trauma room admissions and applied CT dose increase as the severity of injuries decreases. Therefore, appropriateness of established procedures should be re-evaluated., Standard Radiological Methods: Considering severely injured patients with an Injury Severity Score (ISS) ≥16, whole body CT (WB-CT) compared to selective CT decreased mortality by about 25%. Thus, the ISS is a good indicator for the severity of injuries. However, since ISS can only be determined after diagnosis, it does not help with the primary assessment., Methodological Innovation and Evaluation: In addition to the currently used very fast WB-CT protocol with the highest diagnostic precision, a second protocol should be established applying a substantially lower dose. Under ongoing resuscitation, WB-CT often makes a substantial contribution towards targeted therapy or to justifying the discontinuation of resuscitation measures. The WB-CT findings should be performed several times and, at least in the acute emergency situation, it should follow the ABCDE scheme as close as possible., Practical Recommendations: In the trauma room it should be initially decided whether the classification as polytrauma is to be maintained. If yes, every institution should provide a dose-reduced WB-CT protocol in addition to the maximum variant used so far. Dose-reduced WB-CT seems to be appropriate for stable and oriented patients, who receive a CT primarily because of the trauma mechanism. Even under resuscitation conditions, WB-CT is easy to perform and medically as well as ethically of high value. The reporting and communication should be structured according to "diagnose first what kills first".

Clinical Issue: Both the progress of surgical techniques and the demographic development with increasing numbers of multimorbid patients demand and also encourage radiology in the setting of trauma and acute emergencies. In addition to a fast and precise diagnostics, this also includes image-guided, minimally invasive therapy to control and treat several acute pathologies., Standard Radiological Procedures: Computed tomography (CT) is not only important for the diagnosis of abscesses, active bleeding or other acute pathologies, but also allows minimally invasive therapy. While digital subtraction angiography (DSA) guides catheter-based procedures, e.g., to control bleedings or to place percutaneous transhepatic cholangiodrain (PTCD), fluoroscopy allows the 3D-visualization to drain abdominal and thoracic abscesses., Methodological Innovation and Evaluation: Radiology has established itself in the treatment of acute emergencies or acute complications through gentle and usually fast minimally invasive procedures. Presumably, MRI interventions will become increasingly important in the near future and, thus, complement the portfolio., Practical Recommendations: Every clinical radiologist who works on night shifts should be able to safely carry out some basic interventional techniques in order to stabilize the patient and at least ensure medically safe bridging to the next routine workday. Due to the diversity of materials and the rarity and difficulty of some procedures, the full portfolio requires years of expertise and will therefore remain restricted to specialized interventional radiologists.

Objective: The aim of this study was to define optimal tube potential for soft tissue and vessel visualization in dose-reduced chest CT protocols using model-based iterative algorithm in average and overweight patients., Methods: Thirty-six patients receiving chest CT according to 3 protocols (120 kVp/noise index [NI], 60; 100 kVp/NI, 65; 80 kVp/NI, 70) were included in this prospective study, approved by the ethics committee. Patients' physical parameters and dose descriptors were recorded. Images were reconstructed with model-based algorithm. Two radiologists evaluated image quality and lesion conspicuity; the protocols were intraindividually compared with preceding control CT reconstructed with statistical algorithm (120 kVp/NI, 20). Mean and standard deviation of attenuation of the muscle and fat tissues and signal-to-noise ratio of the aorta were measured., Results: Diagnostic images (lesion conspicuity, 95%-100%) were acquired in average and overweight patients at 1.34, 1.02, and 1.08 mGy and at 3.41, 3.20, and 2.88 mGy at 120, 100, and 80 kVp, respectively. Data are given as CT dose index volume values., Conclusions: Model-based algorithm allows for submillisievert chest CT in average patients; the use of 100 kVp is recommended.

Background: In hospitals, the radiological services provided to non-privately insured in-house patients are mostly distributed to requesting disciplines through internal cost allocation (ICA). In many institutions, computed tomography (CT) is the modality with the largest amount of allocation credits., Objectives: The aim of this work is to compare the ICA to respective DRG (Diagnosis Related Groups) shares for diagnostic CT services in a university hospital setting., Materials and Methods: The data from four CT scanners in a large university hospital were processed for the 2012 fiscal year. For each of the 50 DRG groups with the most case-mix points, all diagnostic CT services were documented including their respective amount of GOÄ allocation credits and invoiced ICA value. As the German Institute for Reimbursement of Hospitals (InEK) database groups the radiation disciplines (radiology, nuclear medicine and radiation therapy) together and also lacks any modality differentiation, the determination of the diagnostic CT component was based on the existing institutional distribution of ICA allocations., Results: Within the included 24,854 cases, 63,062,060 GOÄ-based performance credits were counted. The ICA relieved these diagnostic CT services by € 819,029 (single credit value of 1.30 Eurocent), whereas accounting by using DRG shares would have resulted in € 1,127,591 (single credit value of 1.79 Eurocent). The GOÄ single credit value is 5.62 Eurocent., Conclusions: The diagnostic CT service was basically rendered as relatively inexpensive. In addition to a better financial result, changing the current ICA to DRG shares might also mean a chance for real revenues. However, the attractiveness considerably depends on how the DRG shares are distributed to the different radiation disciplines of one institution.

Objective: The aim of the study was to analyse and interpret radiological mass casualty incident workflow data., Methods: In a mid-scale mass casualty incident exercise, the on-site triage assigned 12 cases to the investigated institution (11 included in the study). Two out of five institutional multislice-CT-scanners were used and the whole CT workflow and radiological service process chain were simulated as close to realistic as possible. The respective time intervals for reaching defined milestones were measured., Results: The average CT in-room time, i.e. from entering to leaving the CT room was 9.43 min [(standard deviation) SD: 2.27 min; 95% (confidence interval) CI: 7.90-10.95 min]. Time spent on CT table was 6.75 min (SD: 1.67; CI: 5.63-7.87), and the pure scan time was 4.22 min (SD: 0.64; CI: 3.79-4.65). The first images after entering the CT room were available at a dedicated CT workstation after 5.85 min (SD: 2.20; CI: 4.37-7.32) and institution wide via picture archiving system (PACS) after 7.85 min (SD: 1.27; CI: 7.00-8.71). However, the PACS archiving process, that is, transfer of standard reconstruction set of CT images into the PACS was finished after 20.85 min (SD: 2.97; CI: 18.85-22.84)., Conclusion: Up to six patients may be served per hour and per CT scanner by using a standard whole body CT polytrauma protocol. Dedicated CT triage protocols may even increase this number. The time portion until images were available at end points was relatively long. A solution has to be developed in order to avoid scenarios of patients being faster at end points than their images.

Objective: To investigate whether MRI in emergency radiology can detect (a) additional trauma-related findings after minor head injury (MHI) or (b) structural, non-trauma-related intracranial lesions when trauma biomarker S-100B concentration is raised, or clinical symptoms are unexplained, or both., Methods: 41 patients with MHI were included. Concentrations of S-100B in serum were measured and categorized using an established cut-off at 0.1 μg l(-1). Intracerebral trauma-related as well as non-trauma-related chronic structural findings (atrophy, microangiopathy and chronic parenchymal defects) were assessed by cranial CT (CCT) and MRI by two independent radiologists (UL and LLG). All CCT and MRI results were compared with biomarker S-100B., Results: Compared with CCT, MRI detected 10 additional lesions. 5 patients had abnormal MRI with a total of 15 trauma-related lesions and showed elevated S-100B concentrations. Although sensitivity of S-100B was 100%, specificity was only 25%. Patients with structural brain lesions showed significantly higher S-100B serum levels (0.50 and 0.14 μg l(-1), p = 0.01)., Conclusion: Biomarker S-100B has proven its high negative-predictive value to rule out intracranial bleeding in patients after MHI even if MRI is used as imaging modality. Regarding the low specificity of S-100B, structural lesions of the brain parenchyma not related to the acute trauma may be associated with increased serum concentrations of protein S-100B., Advances in Knowledge: Biomarker S-100B has a high negative-predictive value to rule out intracranial bleeding after MHI. Biomarker S-100B's low specificity may be associated with non-traumatic brain parenchyma lesions. MRI is superior to CCT in detecting subtle findings in neuroimaging after MHI. Biomarker S-100B can potentially reduce the large number of normal CCT studies after MHI.

Precise therapeutic decision-making is vital in managing out-of-hospital cardiac arrest. We present an interesting approach where suspected pulmonary embolism could be confirmed by early computed tomography in cardiac arrest. Chest compressions were performed automatically by mechanical devices also during the acquisition of computed tomography data and subsequent thrombolysis.

Objective: Evaluation of potential dose savings by implementing adaptive statistical iterative reconstruction (ASiR) on a gemstone-based scintillator in a clinical 64-row whole-body CT (WBCT) protocol after multiple trauma., Methods: Dose reports of 152 WBCT scans were analysed for two 64-row multidetector CT scanners (Scanners A and B); the main scanning parameters were kept constant. ASiR and a gemstone-based scintillator were used in Scanner B, and the noise index was adjusted (head: 5.2 vs 6.0; thorax/abdomen: 29.0 vs 46.0). The scan length, CT dose index (CTDI) and dose-length product (DLP) were analysed. The estimated mean effective dose was calculated using normalized conversion factors. Student's t-test was used for statistics., Results: Both the mean CTDI (mGy) (Scanner A: 53.8 ± 2.0, 10.3 ± 2.5, 14.4 ± 3.7; Scanner B: 48.7 ± 2.2, 7.1 ± 2.3, 9.1 ± 3.6; p < 0.001, respectively) and the mean DLP (mGy cm) (Scanner A: 1318.9 ± 167.8, 509.3 ± 134.7, 848.8 ± 254.0; Scanner B: 1190.6 ± 172.6, 354.6 ± 128.3, 561.0 ± 246.7; p < 0.001, respectively) for the head, thorax and abdomen were significantly reduced with Scanner B. There was no relevant difference in scan length. The total mean effective dose (mSv) was significantly decreased with Scanner B (24.4 ± 6.0, 17.2 ± 5.8; p < 0.001)., Conclusion: The implementation of ASiR and a gemstone-based scintillator allows for significant dose savings in a clinical WBCT protocol., Advances in Knowledge: Recent technical developments can significantly reduce radiation dose of WBCT in multiple trauma. Dose reductions of 10-34% can be achieved.

Rationale and Objectives: Dose reduction may compromise patients because of a decrease of image quality. Therefore, the amount of dose savings in new dose-reduction techniques needs to be thoroughly assessed. To avoid repeated studies in one patient, chest computed tomography (CT) scans with different dose levels were performed in corpses comparing model-based iterative reconstruction (MBIR) as a tool to enhance image quality with current standard full-dose imaging., Materials and Methods: Twenty-five human cadavers were scanned (CT HD750) after contrast medium injection at different, decreasing dose levels D0-D5 and respectively reconstructed with MBIR. The data at full-dose level, D0, have been additionally reconstructed with standard adaptive statistical iterative reconstruction (ASIR), which represented the full-dose baseline reference (FDBR). Two radiologists independently compared image quality (IQ) in 3-mm multiplanar reformations for soft-tissue evaluation of D0-D5 to FDBR (-2, diagnostically inferior; -1, inferior; 0, equal; +1, superior; and +2, diagnostically superior). For statistical analysis, the intraclass correlation coefficient (ICC) and the Wilcoxon test were used., Results: Mean CT dose index values (mGy) were as follows: D0/FDBR = 10.1 ± 1.7, D1 = 6.2 ± 2.8, D2 = 5.7 ± 2.7, D3 = 3.5 ± 1.9, D4 = 1.8 ± 1.0, and D5 = 0.9 ± 0.5. Mean IQ ratings were as follows: D0 = +1.8 ± 0.2, D1 = +1.5 ± 0.3, D2 = +1.1 ± 0.3, D3 = +0.7 ± 0.5, D4 = +0.1 ± 0.5, and D5 = -1.2 ± 0.5. All values demonstrated a significant difference to baseline (P < .05), except mean IQ for D4 (P = .61). ICC was 0.91., Conclusions: Compared to ASIR, MBIR allowed for a significant dose reduction of 82% without impairment of IQ. This resulted in a calculated mean effective dose below 1 mSv., (Copyright © 2015 AUR. Published by Elsevier Inc. All rights reserved.)

Purpose: To evaluate the potential of phase-contrast computed tomography (CT) for atherosclerotic plaque imaging in human carotid arteries in an experimental ex vivo study., Materials and Methods: The study was approved by the institutional review board, and informed consent was obtained from the patients' relatives. Seven postmortem human carotid artery specimens were imaged at a laboratory setup by using a conventional x-ray tube and grating interferometer. After histologic processing, phase-contrast imaging and histopathologic data were matched. Characteristics of the necrotic core (NC) covered by a fibrous cap (FC), intraplaque hemorrhage (IPH), and calcifications (CAs) were established, and sensitivity, specificity, and accuracy of phase-contrast CT for plaque detection and the potential for accurate quantification were assessed. The Cohen κ and Pearson correlation coefficient R were used to determine the agreement between phase-contrast imaging and histopathologic findings for plaque characterization and correlation of quantitative plaque measurements, respectively. A difference with a P value of less than .05 was considered significant., Results: Characteristic criteria were found in all analyzed plaque components. Applying these criteria, phase-contrast CT had a good sensitivity for the detection of the FC and NC, IPH, and CAs (all, >80%) and excellent specificity and accuracy (all, >90%), with good interreader agreement (κ ≥ 0.72, P < .0001). There were excellent correlations for quantitative measurements of FC, NC, and CAs between phase-contrast imaging and histopathologic findings (R ≥ 0.92). Interreader reproducibility was excellent, with an intraclass correlation coefficient of 0.98 or higher for all measurements., Conclusion: The results of this study indicate that ex vivo phase-contrast CT can help identify and quantify atherosclerotic plaque components, with excellent correlation to histopathologic findings. Although not yet applicable in vivo, phase-contrast CT may become a valuable tool to monitor atherosclerotic disease process noninvasively.

Purpose: To determine the lower limit of dose reduction with hybrid and fully iterative reconstruction algorithms in detection of endoleaks and in-stent thrombus of thoracic aorta with computed tomographic (CT) angiography by applying protocols with different tube energies and automated tube current modulation., Materials and Methods: The calcification insert of an anthropomorphic cardiac phantom was replaced with an aortic aneurysm model containing a stent, simulated endoleaks, and an intraluminal thrombus. CT was performed at tube energies of 120, 100, and 80 kVp with incrementally increasing noise indexes (NIs) of 16, 25, 34, 43, 52, 61, and 70 and a 2.5-mm section thickness. NI directly controls radiation exposure; a higher NI allows for greater image noise and decreases radiation. Images were reconstructed with filtered back projection (FBP) and hybrid and fully iterative algorithms. Five radiologists independently analyzed lesion conspicuity to assess sensitivity and specificity. Mean attenuation (in Hounsfield units) and standard deviation were measured in the aorta to calculate signal-to-noise ratio (SNR). Attenuation and SNR of different protocols and algorithms were analyzed with analysis of variance or Welch test depending on data distribution., Results: Both sensitivity and specificity were 100% for simulated lesions on images with 2.5-mm section thickness and an NI of 25 (3.45 mGy), 34 (1.83 mGy), or 43 (1.16 mGy) at 120 kVp; an NI of 34 (1.98 mGy), 43 (1.23 mGy), or 61 (0.61 mGy) at 100 kVp; and an NI of 43 (1.46 mGy) or 70 (0.54 mGy) at 80 kVp. SNR values showed similar results. With the fully iterative algorithm, mean attenuation of the aorta decreased significantly in reduced-dose protocols in comparison with control protocols at 100 kVp (311 HU at 16 NI vs 290 HU at 70 NI, P ≤ .0011) and 80 kVp (400 HU at 16 NI vs 369 HU at 70 NI, P ≤ .0007)., Conclusion: Endoleaks and in-stent thrombus of thoracic aorta were detectable to 1.46 mGy (80 kVp) with FBP, 1.23 mGy (100 kVp) with the hybrid algorithm, and 0.54 mGy (80 kVp) with the fully iterative algorithm.

Objectives: To compare the effects of different arm positions on dose exposure and image quality (IQ) in cervical spine CT after trauma in different patient groups., Methods: Patients in standard (STD = 126) and in swimmer's position (SWIM = 254) were included. Body mass index (BMI subgroup 1 = underweight to subgroup 4 = obese), anterior-posterior diameter (AP), left-right diameter (LR), area of an ellipse (AoE) and angle between the humeral heads (optimal STD < 3°, optimal SWIM > 10°) were used as grouping criteria. Computed tomography dose index (CTDI) was documented. Two radiologists rated the IQ at three levels (CV1/2, CV4/5, CV7/T1) using a semi-quantitative scale (0 = not diagnostic, 1 = diagnostic with limitations, 2 = diagnostic without limitations). The Mann-Whitney U test correlations of grouping criteria with dose effects and intra-class correlation (ICC) were calculated., Results: ICC was 0.87. BMI grouping showed the strongest correlation with dose effects: CTDI of optimal STD versus optimal SWIM positioning was 3.17 mGy versus 2.46 mGy (subgroup 1), 5.47 mGy versus 3.97 mGy (subgroup 2), 7.35 mGy versus 5.96 mGy (subgroup 3) and 8.71 mGy versus 8.18 mGy (subgroup 4). Mean IQ at CV7/T1 was 1.65 versus 1.23 (subgroup 1), 1.27 versus 1.46 (subgroup 2), 1.06 versus 1.46 (subgroup 3), 0.79 versus 1.5 (subgroup 4)., Conclusion: Patients with a BMI > 20 kg/m(2) benefited from both potential dose reduction and improved image quality at the critical cervicothoracic junction when swimmer's position was used., Key Points: • BMI is a useful metric for personalized optimization in CT for the c-spine. • Using swimmer's position, patients can benefit from dose reduction. • In some patients a superior image quality can be achieved with swimmer's position. • For swimmer's positioning an angle of more than 10° is optimal.

The respiratory and the cardiovascular systems are intimately connected. Because of the high degree of morphological and functional interaction, pathophysiological processes in one compartment are likely to induce adaptive changes in the other. Computed tomography (CT) plays a central role in the diagnostic work up of both thoracic and cardiac disorders. Historically, these two systems have been evaluated separately; however, CT technology has evolved remarkably over recent decades. Up-to-date advanced imaging strategies allow for a combined assessment of the cardiopulmonary unit. Besides improved techniques of electrocardiogram (ECG)-synchronization for obtaining both morphological and functional information, latest advances of dual-source CT (DSCT) have shown great promise for even more comprehensive integrated cardiothoracic imaging., (Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.)

Traumatic injuries are the leading cause of death in adults < 45 years of age. Musculoskeletal trauma accounts for a substantial number of injuries in patients sustaining polytrauma. The diagnostic work-up of those patients is challenging, complex, and requires a structured and interdisciplinary workflow. Multidetector CT (MDCT) is considered the imaging modality of choice due to remarkable technical developments in recent years. Besides the evaluation of cranial, chest, and abdominal injuries, MDCT allows for integrated imaging of musculoskeletal trauma within a single CT examination. In this context, CT angiography facilitates the detection of coexisting vascular injuries after trauma of the skeleton. In addition, recent technologies (e.g., dual-energy CT) provide promising applications such as metal artifact reduction. This article summarizes the basic principles of interdisciplinary management of polytrauma patients, reviews recent advances of CT technology that have enabled comprehensive trauma imaging, provides appropriate scan protocols, and discusses the radiologic evaluation of musculoskeletal findings., (Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.)

Purpose: To compare the image quality in dose-reduced 64-row CT of the chest at different levels of adaptive statistical iterative reconstruction (ASIR) to full-dose baseline examinations reconstructed solely with filtered back projection (FBP) in a realistic upgrade scenario., Materials and Methods: A waiver of consent was granted by the institutional review board (IRB). The noise index (NI) relates to the standard deviation of Hounsfield units in a water phantom. Baseline exams of the chest (NI = 29; LightSpeed VCT XT, GE Healthcare) were intra-individually compared to follow-up studies on a CT with ASIR after system upgrade (NI = 45; Discovery HD750, GE Healthcare), n = 46. Images were calculated in slice and volume mode with ASIR levels of 0 - 100 % in the standard and lung kernel. Three radiologists independently compared the image quality to the corresponding full-dose baseline examinations (-2: diagnostically inferior, -1: inferior, 0: equal, + 1: superior, + 2: diagnostically superior). Statistical analysis used Wilcoxon's test, Mann-Whitney U test and the intraclass correlation coefficient (ICC)., Results: The mean CTDIvol decreased by 53 % from the FBP baseline to 8.0 ± 2.3 mGy for ASIR follow-ups; p < 0.001. The ICC was 0.70. Regarding the standard kernel, the image quality in dose-reduced studies was comparable to the baseline at ASIR 70 % in volume mode (-0.07 ± 0.29, p = 0.29). Concerning the lung kernel, every ASIR level outperformed the baseline image quality (p < 0.001), with ASIR 30 % rated best (slice: 0.70 ± 0.6, volume: 0.74 ± 0.61)., Conclusion: Vendors' recommendation of 50 % ASIR is fair. In detail, the ASIR 70 % in volume mode for the standard kernel and ASIR 30 % for the lung kernel performed best, allowing for a dose reduction of approximately 50 %., (© Georg Thieme Verlag KG Stuttgart · New York.)

Purpose: To compare objective and subjective image quality parameters of three image reconstruction algorithms of different generations at routine multidetector computed tomographic (CT) examinations of the abdomen., Materials and Methods: This institutional review board-approved study included 22 consecutive patients (mean age, 56.1 years ± 15.8 [standard deviation]; mean weight, 79.1 kg ± 14.8) who underwent routine CT examinations of the abdomen. A low-contrast phantom was used for objective quality control. Raw data sets were reconstructed by using filtered back projection (FPB), adaptive statistical iterative reconstruction (ASIR), and a model-based iterative reconstruction (MBIR). Radiologists used a semiquantitative scale (-3 to +3) to rate subjective image quality and artifacts, comparing both FBP and MBIR images with ASIR images. The Wilcoxon test and the intraclass correlation coefficient were used to evaluate the data. Measurements of objective noise and CT numbers of soft tissue structures were compared with analysis of variance., Results: The phantom study revealed an improved detectability of low-contrast targets for MBIR compared with ASIR or FBP. Subjective ratings showed higher image quality for MBIR, with better resolution (median value, 2; range, 1 to 3), lower noise (2; range, 1 to 3), and finer contours (2; range, 1 to 2) compared with ASIR (all P < .001). FBP performed inferiorly (0, range, -2 to 0]; -1 [range, -3 to 0]; 0 [range, -1 to 0], respectively; all, P < .001). Mean interobserver correlation was 0.9 for image perception and 0.7 for artifacts. Objective noise for FBP was 14%-68% higher and for MBIR was 18%-47% lower than that for ASIR (P < .001)., Conclusion: The MBIR algorithm considerably improved objective and subjective image quality parameters of routine abdominal multidetector CT images compared with those of ASIR and FBP., (RSNA, 2012)

Purpose: Computed tomography pulmonary angiography (CTPA) is considered as clinical gold standard for diagnosing pulmonary embolism (PE). Whereas conventional CTPA only offers anatomic information, dual energy CT (DECT) provides functional information on blood volume as surrogate of perfusion by assessing the pulmonary iodine distribution. The purpose of this study was to evaluate the feasibility of lung perfusion imaging using a single-tube DECT scanner with rapid kVp switching., Materials and Methods: Fourteen patients with suspicion of acute PE underwent DECT. Two experienced radiologists assessed the CTPA images and lung perfusion maps regarding the presence of PE. The image quality was rated using a semi-quantitative 5-point scale: 1 (=excellent) to 5 (=non-diagnostic). Iodine concentrations were quantified by a ROI analysis., Results: Seventy perfusion defects were identified in 266 lung segments: 13 (19%) were rated as consistent with PE. Five patients had signs of PE at CTPA. All patients with occlusive clots were correctly identified by DECT perfusion maps. On a per patient basis the sensitivity and specificity were 80.0% and 88.9%, respectively, while on a per segment basis it was 40.0% and 97.6%, respectively. None of the patients with a homogeneous perfusion map had an abnormal CTPA. The overall image quality of the perfusion maps was rated with a mean score of 2.6 ± 0.6. There was a significant ventrodorsal gradient of the median iodine concentrations (1.1mg/cm(3) vs. 1.7 mg/cm(3))., Conclusion: Lung perfusion imaging on a DE CT-system with fast kVp-switching is feasible. DECT might be a helpful adjunct to assess the clinical severity of PE., (Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.)

Objective: To compare abdominal computed tomography (CT) scout views with conventional radiography regarding radiation dose and delineation of drug packages in a porcine body-packer model., Materials and Methods: Nine samples of illicit drugs packed in ovoid plastic containers were consecutively placed in the rectum of a 121.5 kg pig cadaver. Antero-posterior and lateral scout views were obtained at 120 kVp and 80 mA, 150 mA and 200 mA, respectively, using a 64-row MDCT. Scout views were compared with conventional abdominal antero-posterior radiographs (77 kV and 106 ± 13 mAs). Visibility of three body pack characteristics (wrapping, content, shape) was rated independently by two radiologists and summarized to a delineation score ranging from 0 to 9 with a score ≥ 6 representing sufficient delineation. Mean delineation scores were calculated for each conventional radiography and single plane scout view separately and for a combined rating of antero-posterior and lateral scout views., Results: Even the lowest single plane scout view delineation score (5.3 ± 2.0 for 80 mA lateral; 0.4 mSv; sensitivity=44%) was significantly higher than for conventional radiographs (3.1 ± 2.5, p<0.001; 2.4 ± 0.3 mSv; sensitivity=11%). Combined reading of antero-posterior and lateral scout views 80 mA yielded sufficient delineation (6.2 ± 1.4; 0.8 mSv; sensitivity=56%)., Conclusions: All CT scout views showed significantly better delineation ratings and sensitivity than conventional radiographs. Scout views in two planes at 80 mA provided a sufficient level of delineation and a sensitivity five times higher than conventional radiography at less than one third of the radiation dose. In case of diagnostic insecurity, CT can be performed without additional logistical effort., (Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.)

Purpose: To compare the image quality of dose-reduced 64-row abdominal CT reconstructed at different levels of adaptive statistical iterative reconstruction (ASIR) to full-dose baseline examinations reconstructed with filtered back-projection (FBP) in a clinical setting and upgrade situation., Materials and Methods: Abdominal baseline examinations (noise index NI = 29; LightSpeed VCT XT, GE) were intra-individually compared to follow-up studies on a CT with an ASIR option (NI = 43; Discovery HD750, GE), n = 42. Standard-kernel images were calculated with ASIR blendings of 0 - 100 % in slice and volume mode, respectively. Three experienced radiologists compared the image quality of these 567 sets to their corresponding full-dose baseline examination (- 2: diagnostically inferior, - 1: inferior, 0: equal, + 1: superior, + 2: diagnostically superior). Furthermore, a phantom was scanned. Statistical analysis used the Wilcoxon - the Mann-Whitney U-test and the intra-class correlation (ICC)., Results: The mean CTDIvol decreased from 19.7 ± 5.5 to 12.2 ± 4.7 mGy (p < 0.001). The ICC was 0.861. The total image quality of the dose-reduced ASIR studies was comparable to the baseline at ASIR 50 % in slice (p = 0.18) and ASIR 50 - 100 % in volume mode (p > 0.10). Volume mode performed 73 % slower than slice mode (p < 0.01)., Conclusion: After the system upgrade, the vendor recommendation of ASIR 50 % in slice mode allowed for a dose reduction of 38 % in abdominal CT with comparable image quality and time expenditure. However, there is still further dose reduction potential for more complex reconstruction settings., (© Georg Thieme Verlag KG Stuttgart · New York.)

Objective: The purpose of this study was to evaluate the impact of the use of 64-MDCT and volume image reading on the radiologic workflow during a mass casualty incident simulation., Materials and Methods: For this simulation, casualties were taken to our level I trauma center, and triage was done with whole-body 64-MDCT. The complete raw dataset of thin-section images was sent to a dedicated 3D workstation for further interpretation and simultaneous reformations. This new reading method is called volume image reading. Several time frames were documented to evaluate the workflow: examination time, time needed for image processing, and mean image transfer rates. The results were compared with those of a previous study using a 4-MDCT with axial images only and transfer of data to a PACS., Results: The time for complete image processing (acquisition, reconstruction, and transfer) for 64-MDCT was 4.1 minutes (range, 3.9-4.3 minutes) compared with 9.0 minutes (range, 6.4-10.2 minutes) for 4-MDCT (p ≤ 0.001). The image processing capacity was 14.8 examinations/h for 64-MDCT compared with 6.7 examinations/h for 4-MDCT. The mean number of images was 953 for 64-MDCT compared with 202 for 4-MDCT (p ≤ 0.001). There were no significant differences between 64- and 4-MDCT for the time needed to prepare patients., Conclusion: The use of 64-MDCT with volume image reading led to evident advantages in the radiologic trauma workflow compared with 4-MDCT. Reading of the full image set including reformations can be initiated earlier with volume image reading.

The purpose of the study was to evaluate both CT image quality in a phantom study and feasibility in an initial case series using automated chest compression (A-CC) devices for cardiopulmonary resuscitation (CPR). Multidetector CT (MDCT) of a chest/heart phantom (Thorax-CCI, QRM, Germany) was performed with identical protocols of the phantom alone (S), the phantom together with two different A-CC devices (A: AutoPulse, Zoll, Germany; L: LUCAS, Jolife, Sweden), and the phantom with a LUCAS baseplate, but without the compression unit (L-bp). Nine radiologists evaluated image noise quantitatively (n = 244 regions, Student's t-test) and also rated image quality subjectively (1-excellent to 6-inadequate, Mann-Whitney U-test). Additionally, three patients during prolonged CPR underwent CT with A-CC devices. Mean image noise of S was increased by 1.21 using L-bp, by 3.62 using A, and by 5.94 using L (p < 0.01 each). Image quality was identical using S and L-bp (1.64 each), slightly worse with A (1.83), and significantly worse with L (2.97, p < 0.001). In all patient cases the main lesions were identified, which led to clinical key decisions. Image quality was excellent with L-bp and good with A. Under CPR conditions initial cases indicate that MDCT diagnostics supports either focused treatment or the decision to terminate efforts.

The purpose of this study was to evaluate the feasibility, stability, and reproducibility of a dedicated CT protocol for the triage of patients in two separate large-scale exercises that simulated a mass casualty incident (MCI). In both exercises, a bomb explosion at the local soccer stadium that had caused about 100 casualties was simulated. Seven casualties who were rated "critical" by on-site field triage were admitted to the emergency department and underwent whole-body CT. The CT workflow was simulated with phantoms. The history of the casualties was matched to existing CT examinations that were used for evaluation of image reading under MCI conditions. The times needed for transfer and preparation of patients, examination, image reconstruction, total time in the CT examination room, image transfer to PACS, and image reading were recorded, and mean capacities were calculated and compared using the Mann-Whitney U test. We found no significant time differences in transfer and preparation of patients, duration of CT data acquisition, image reconstruction, total time in the CT room, and reading of the images. The calculated capacities per hour were 9.4 vs. 9.8 for examinations completed, and 8.2 vs. 7.2 for reports completed. In conclusion, CT triage is feasible and produced constant results with this dedicated and fast protocol.

Pancreatic and duodenal injuries after blunt abdominal trauma are rare; however, delays in diagnosis and treatment can significantly increase morbidity and mortality. Multidetector computed tomography (CT) has a major role in early diagnosis of pancreatic and duodenal injuries. Detecting the often subtle signs of injury with whole-body CT can be difficult because this technique usually does not include a dedicated protocol for scanning the pancreas. Specific injury patterns in the pancreas and duodenum often have variable expression at early posttraumatic multidetector CT: They may be hardly visible, or there may be considerable exudate, hematomas, organ ruptures, or active bleeding. An accurate multidetector CT technique allows optimized detection of subtle abnormalities. In duodenal injuries, differentiation between a contusion of the duodenal wall or mural hematoma and a duodenal perforation is vital. In pancreatic injuries, determination of involvement of the pancreatic duct is essential. The latter conditions require immediate surgical intervention. Use of organ injury scales and a surgical classification adapted for multidetector CT enables classification of organ injuries for trauma scoring, treatment planning, and outcome control. In addition, multidetector CT reliably demonstrates potential complications of duodenal and pancreatic injuries, such as posttraumatic pancreatitis, pseudocysts, fistulas, exudates, and abscesses., ((c) RSNA, 2008.)

Objective: Staging of bronchial carcinoma presents a diagnostic challenge. In addition to CT scans, endobronchial ultrasound is used. The aim of this study was to compare the diagnostic accuracy of high-resolution multidetector CT (MSCT) with that of endobronchial ultrasound with respect of detection and extension of the bronchial lesions., Methods: 24 patients with lesions in the central bronchial area were examined using both EBUS and MSCT. Multiplanar reconstructions (MPR) as well as virtual endoscopy (VE) were used as adjuncts in this investigation of the comparative diagnostic accuracy of MSCT and EBUS in the imaging of bronchial lesions., Results: No significant difference could be established between EBUS and MSCT in detecting and extension of bronchial lesions. With both procedures, the use of supplementary techniques may be advantageous and helpful in individual cases., Conclusions: When compared with EBUS, MSCT with post-processing has equally high sensitivity with regard to the visualization of malign endobronchial lesions.

Background: The purpose of this study was to evaluate the value of C-arm CT imaging of the distal radius with standard patient positioning in intraoperative assessment of plate osteosynthesis., Materials and Methods: Four complete distal radius specimens from human cadavers were fractured (type C), and internal fixation with palmar plates (stainless steel) was then carried out in each. On the basis of C-arm fluoroscopy, radiography and C-arm CT (Siremobil Iso-C3D, scans with forearm bones positioned parallel to the z-axis), 19 observers subsequently evaluated the positions of screws near the joint and any steps within the joint, after which the bones were surgically exposed and the imaging results checked against direct visual observations., Results: No statistically significant differences were detected either between the modalities or between the evaluator groups., Conclusion: With standard patient positioning, the performance of C-arm CT was equivalent to and not better than that of current standard procedures, i.e. intraoperative fluoroscopy and postoperative radiography. Further studies should examine whether this holds true in clinical practice with representative patient collectives when titanium implants are used and/or optimized patient positioning is practised.

The purpose of this study was to analyze different patient positioning strategies for minimizing artifacts of the shoulder girdle in head and neck CT. Standardized CT examinations of three positioning groups were compared (P: patients pushed their shoulders downwards; D: similar optimization by a pulling device; N: no particular positioning optimization). Parameters analyzed were the length of the cervical spine not being superimposed by the shoulder girdle as well as noise in the supraclavicular space. In groups P and D, the portion of the cervical spine not superimposed was significantly larger than in group N (P: 10.4 cm; D: 10.6 cm; N: 8.5 cm). At the supraclavicular space, noise decreased significantly (P: 12.5 HU; D: 12.1 HU; N: 17.7 HU). No significant differences between the two position-optimized groups (P and D) were detected. Optimized shoulder positioning by the patient increases image quality in CT head and neck imaging. The use of a pulling device offers no additional advantages.

Purpose: Recommendations for archiving digital radiological image data based on the comparison of retrieval times for different PACS archive levels., Materials and Methods: For a large PACS installation (Agfa Impax, Release 4.1), image retrieval times for radiological standard examinations (chest radiographs with 2, MRI with 250, CT with 100 and 1000 images; n = 120, each) from hard disk array, magneto-optical disk (MOD), and magnetic tape archives (TAPE) were examined in high and low network traffic load., Results: Even large CT examinations (1000 images) were available from hard disk arrays within 4.0 +/- 0.8 s, smaller studies within 1.8 +/- 0.3 s. Radiographic image retrieval from MOD (30 +/- 4.7 s) was more then 50 % faster than from TAPE. For typical cross-sectional studies, the velocity gain amounted to 19 %. For both technologies, no significant difference was found for large CT examinations (651 +/- 144 s). For high and low network traffic load scenarios, image retrieval times from hard disk, MOD, and TAPE archives increased by 87 %, 7 %, and 22 %, respectively., Conclusion: Hard disk arrays are specifically suited as departmental intermediate storage media because they allow fast access to current and previous examinations within a short time. Performance properties enable both MOD and TAPE systems to serve as long-term archives. However, MOD archives are less flexible in the expansion of storage capacity and at present the medium costs per memory unit are about 2 - 3 times higher than for tape archives. The use of existing MOD-archives may be adequate as intermediate archives. For new PACS installations or system expansions, however, it is recommended to combine a sufficiently large local data memory (RAID) with data storage on tape archives outside the radiological unit that can be used by other departments as well. Future development of hard disk prices will show whether archiving for the whole data retention period may be handled by RAID systems. In any case, prefetching problems and waiting periods for demanded pre-studies would not occur any more.

Objective: To analyse the image quality and diagnostic effectiveness of a new C-arm-based 3D imaging method (C-arm-CT) for intraoperative evaluation of screw osteosyntheses adjacent to a peripheral joint., Materials and Methods: Insertion of screws into four cadaveric specimens simulated the surgical treatment of talus neck fractures. Ten orthopedic surgeons and 10 radiologists evaluated X-ray, C-arm fluoroscopy, C-arm-CT and CT images., Results: The best image quality was obtained with X-rays (p < 0.001), followed by C-arm fluoroscopy (2D) and CT, with the C-arm-CT (3D) being rated lowest (p < 0.001). The most correct diagnoses were obtained with CT and C-arm-CT (with no statistical difference between them), while C-arm-fluoroscopy was inferior (p < 0.001) and X-rays were the worst (p < 0.05)., Conclusions: Even if the image quality of C-arm-CT is definitely inferior to that of CT, screw misplacements can be reliably detected using C-arm-CT. As compared to the current standard procedures (intraoperative fluoroscopy and postoperative radiography), C-arm-CT performed better. C-arm-CT is ideally suited to the intraoperative diagnosis of high-contrast inquiries like bone fragments and OS material, especially at the extremities. Coupling of the new 3D imaging to existing navigation systems is possible. C-arm-CT will support the further development and implementation of open and minimally invasive surgical procedures.

A portable C arm was modified for cone-beam computed tomography (CT). This three-dimensional (3D) CT imaging system facilitated the acquisition of fluoroscopic images during a 190 degrees rotation and computed a 3D data cube (matrix, 256 x 256 x 256; scanning time, 100 seconds) with multiplanar image reformation. The high-contrast resolution, 0.9 line pairs per millimeter, was comparable; the low-contrast resolution, minimal; and the radiation dose, 60%-80% lower, as compared with these parameters at spiral CT. The normal anatomy of small joints could be depicted, and the osteosynthesis screws in the talus were correctly identified.

Purpose: Evaluation of 3D-CT imaging of the axial skeleton and different joints of the lower and upper extremities with a new dedicated CT system (ISO-C-3D) based on a mobile isocentric C-arm image amplifier., Material and Methods: 27 cadaveric specimes of different joints of the lower and upper extremities and of the spinal column were examined with 3D-CT imaging (ISO-C-3D). All images were evaluated by 3 radiologists for image quality using a semiquantitative score (score value 1: poor quality; score value 4: excellent quality). In addition, dose measurements and measurements of high contrast resolution were performed in comparison to conventional and low-dose spiral CT using a high contrast phantom (Catphan, Phantom Laboratories)., Results: Adequate image quality (mean score values 3 - 4) could be achieved with an applied dose comparable to low-dose CT in smaller joints such as wrist, elbow, ankle and knee. A remarkably inferior image quality resulted in imaging of the hip, lumbar and thoracic spine (mean score values 2 - 3) in spite of almost doubling the dose (dose increased by 85 percent). The image quality of shoulder examinations was insufficient (mean score value 1). Phantom studies showed a high-contrast resolution comparable to helical CT in the xy-axis (9 lp/cm)., Conclusion: Preliminary results show, that image quality of C-arm-based CT-imaging (ISO-C-3D) seems to be adequate in smaller joints. ISO-C-3D images of the hip and axial skeleton show a decreased image quality, which does not seem to be sufficient for diagnosing subtle fractures.

Preclinical evaluation of a new mobile C-arm image amplifier with an option for three-dimensional computed tomography (CT) imaging (prototype Iso-C3D) with respect to high-contrast resolution and possible clinical applications. Cadaveric specimens (n = 30) of different joints of the lower and upper extremities and specimens of the spinal column were examined with the Iso-C3D and evaluated for image quality. In addition, using a high-contrast phantom (Catphan, Phantom Laboratory, Salem, N.Y., USA) and a fracture model of the femoral bone, measurements of high-contrast resolution were performed in comparison to spiral CT. With the exception of the shoulder, all joint regions including the entire spinal column could be examined. Adequate image quality could be achieved in smaller joints such as the wrist, elbow, ankle, and knee, whereas a remarkably decreased image quality was found when imaging the hip as well as the lumbar and thoracic spine. Images of the phantom study and high-contrast fracture model showed a high-contrast resolution comparable to helical CT (9 Lp/cm in xy-axis). In smaller joints, the image quality of the mobile C-arm CT imaging system (Iso-C3D) is comparable to that of helical CT. Image quality in examinations of the hip and lumbar and thoracic spine seems to be sufficient for intraoperative control studies of osteosynthesis. Problems still occur in shoulder examinations.

Malposition of extraosseous or intra-articular screws, e.g., in osteosyntheses of joint fractures or in the vicinity of joints, frequently remains undiscovered in intraoperative fluoroscopy and is only recognized on postoperative computed tomography (CT) scans. The aim of the study, therefore, was to assess the value of a new mobile C-arm three-dimensional imaging device in comparison with fluoroscopy, conventional radiographs, and CT scans using an extremity model. Screws were inserted ventrally in four anatomic lower leg specimens without talus fractures parallel to the longitudinal axis to simulate surgical management of fractures of the talus. The specimens supplied were examined with fluorscopy, conventional radiography, spiral CT, and the new three-dimensional imaging with the SIREMOBIL Iso-C3D. These four modalities were evaluated by ten radiologists and ten trauma surgeons and were compared regarding subjective image quality and position of the screws. The quality of information acquired with the SIREMOBIL Iso-C3D was equal to that of the CT examinations, although image quality was considered inferior to fluoroscopy, conventional radiography, and CT (p < 0.001). In contrast to the previous procedure with intraoperative fluoroscopy and subsequent postoperative X-ray control, the results obtained with the SIREMOBIL IsoC3D were superior. The SIREMOBIL Iso-C3D is useful for the intraoperative diagnosis of small joints with few artifacts producing osteosynthesis material, i.e., for recognizing the position of screws in the region of glenoid surfaces.

To analyze a prototype mobile C-arm image amplifier (Iso-C3D) in the evaluation of different joint fractures of the upper and lower limbs using multiplanar reconstruction (MPR). Different cadaver joint specimens (n = 14) were examined with a prototype (Iso-C3D, Siemens AG, Erlangen, Germany), plain radiographs (CR), and spiral computed tomography (CT). The motorized C-arm provides fluoroscopic images during a 190 degrees orbital rotation computing a 119-mm data cube. These three-dimensional data sets yielded MPR images, which were evaluated by two readers for the detection and extent of fracture lines. Initial data show that fractures were easily depicted and correctly classified on MPR images with the Iso-C3D and that there was no difference between the Iso-C and CT in the detection of fractures. The preliminary results suggest a remarkably good detection of joint fractures with the Iso-C3D. Studies in an adequate number of patients are required to elucidate whether these promising results can also be obtained in a clinical setting.

Objective: This study evaluates the feasibility, safety, and efficacy of power-injecting IV contrast media through central venous catheters for CT examinations., Subjects and Methods: Two hundred ninety-five CT examinations were performed during an 18-month period in 225 patients with indwelling central venous catheters. Patients were randomized to power injection either through peripheral IV catheter or through central venous catheter. Feasibility was defined as the percentage of patients with contrast material injected successfully through the randomized access route. Safety was evaluated by comparing patients with complications. Efficacy was evaluated by comparing contrast enhancement of the thoracic aorta, pulmonary artery, abdominal aorta, and liver., Results: Two hundred nine patients had randomization data recorded. One hundred three (94%) of 109 patients were successfully injected through their indwelling catheter compared with 42 (42%) of 100 through a peripherally placed IV catheter (p < 0.001). After reassignment for unsuccessful access, 174 patients underwent central venous catheter injection, and 51, peripheral IV catheter injection. No statistically significant difference was noted in the complications between the central venous catheter and peripheral IV catheter groups. Enhancement was greater in the thoracic aorta, pulmonary artery, and liver for the peripheral IV catheter group (p < 0.03)., Conclusion: Power injection of contrast media through central venous catheters for CT examinations is feasible and safe when set hospital guidelines and injection protocols are followed. This technique provides an acceptable alternative in patients without adequate peripheral IV access when bolus contrast enhancement is desired.

Purpose: Computerized tomography (CT) is the diagnostic and staging modality of choice for renal neoplasms. Existing imaging modalities are limited by a 2-dimensional (D) format. Recent advances in computer technology now allow the production of high quality 3-D images from helical CT. Nephron sparing surgery requires a detailed understanding of renal anatomy. Preoperative evaluation must delineate the relationship of the tumor to adjacent normal structures and demonstrate the vascular supply to the tumor for the surgeon to conserve as much normal parenchyma as possible. We propose that helical CT combined with 3-D volume rendering provides all of the information required for preoperative evaluation and intraoperative management of nephron sparing surgery cases. We prospectively evaluated the role of 3-D volume rendering CT in 60 patients undergoing nephron sparing surgery for renal cell carcinoma at the Cleveland Clinic Foundation., Materials and Methods: Triphasic spiral CT was performed preoperatively in 60 consecutive patients undergoing nephron sparing surgery for renal neoplasms. A 3 to 5-minute videotape was prepared using volume rendering software which demonstrated the position of the kidney, location and depth of extension of the tumor(s), renal artery(ies) and vein(s), and relationship of the tumor to the collecting system. These videotapes were viewed by a radiologist and urologist in the operating room at surgery, and immediately correlated with surgical findings. Corresponding renal arteriograms of 19 patients were retrospectively compared to 3-D volume rendering CT and operative findings., Results: A total of 97 renal masses were identified in 60 cases evaluated with 3-D volume rendering CT before nephron sparing surgery. There were no complications related to the 3-D protocol and 3-D rendering was successful in all patients. The number and location of lesions identified by 3-D volume rendering CT were accurate in all cases, while enhancement and diagnostic characteristics were consistent with pathological findings in 95 of 97 tumors (98%). Of 77 renal arteries identified at surgery 74 were detected by 3-D volume rendering CT (96%). Helical CT missed 3 small accessory arteries, including 1 in a cross fused ectopic kidney. All major venous branches and anomalies were identified, including 3 circumaortic left renal veins. Of 69 renal veins identified at surgery 64 were detected by 3-D volume rendering CT (93%). All 5 renal veins missed by CT were small, short, duplicated right branches of the main renal vein. Renal fusion and malrotation anomalies were correctly identified in all 4 patients., Conclusions: The 3-D volume rendering CT accurately depicts the renal parenchymal and vascular anatomy in a format familiar to most surgeons. The data integrate essential information from angiography, venography, excretory urography and conventional 2-D CT into a single imaging modality, and can obviate the need for more invasive imaging. Additionally, the use of videotape in an intraoperative setting provides concise, accurate and immediate 3-D information to the surgeon, and it has become the preferred means of data display for these procedures at our center.