Multidetector Computed Tomography Examinations Research Articles

Hepatic Pseudolesion Around the Falciform Ligament

The aim of this study was to determine the prevalence and aberrant venous supply (inferior veins of Sappey) of hypoattenuating hepatic pseudolesions seen around the falciform ligament on portal-dominant phase multidetector computed tomography (MDCT) and the frequency of fatty infiltration of these pseudolesions on chemical-shift magnetic resonance imaging. Portal-dominant phase abdominal MDCT examinations of 728 patients were evaluated for the presence of a pseudolesion around the falciform ligament, and those with a presumed pseudolesion underwent chemical-shift magnetic resonance imaging to detect the fatty infiltration. Reconstructed MDCT images were investigated for the presence of an inferior vein of Sappey, and 30 patients without a pseudolesion were evaluated as a control group. A total of 160 pseudolesions were detected around the falciform ligament in 146 (20%) patients. The longest diameter of the pseudolesions was in the craniocaudal direction in most patients (61%). An inferior vein of Sappey supplying these pseudolesions was depicted in 40 (27%) patients, and it was highly significant (P = 0.001) compared with the controls for the presence of a pseudolesion around the falciform ligament. Fatty infiltration was found in 47 (29%) patients. Hepatic pseudolesions around the falciform ligament are frequently encountered on portal-dominant phase MDCT images. Detection of craniocaudal extension, inferior veins of Sappey, and fatty infiltration of these pseudolesions, which were firstly described in this article, with the largest subject group based on cross-sectional imaging, might be valuable in excluding true tumors.

Angular on‐line tube current modulation in multidetector CT examinations of children and adults: The influence of different scanning parameters on dose reduction

The purpose of this study was to assess the potential of angular on-line tube current modulation on dose reduction in pediatric and adult patients undergoing multidetector computed tomography (MDCT) examinations. Five physical anthropomorphic phantoms that simulate the average individual as neonate, 1-year-old, 5-year-old, 10-year-old, and adult were employed in the current study. Phantoms were scanned with the use of on-line tube current modulation (TCM). Percent dose reduction (%DR) factors achieved by applying TCM, were determined for standard protocols used for head and neck, shoulder, thorax, thorax and abdomen, abdomen, abdomen and pelvis, pelvis, and whole body examinations. A preliminary study on the application of TCM in MDCT examinations of adult patients was performed to validate the results obtained in anthropomorphic phantoms. Dose reduction was estimated as the percentage difference of the modulated milliamperes for each scan and the preset milliamperes prescribed by the scan protocol. The dose reduction in children was found to be much lower than the corresponding reduction achieved for adults. For helical scans the %DR factors, ranged between 1.6% and 7.4% for the neonate, 2.9% and 8.7% for the 1-year old, 2% and 6% for the 5-year-old, 5% and 10.9% for the 10-year-old, and 10.4% and 20.7% for the adult individual. For sequential scans the corresponding %DR factors ranged between 1.3% and 6.7%, 4.5% and 11%, 4.2% and 6.6%, 6.4% and 12.3%, and 8.9% and 23.3%, respectively. Broader beam collimations are associated with decreased %DR factors, when other scanning parameters are held constant. TCM did not impair image noise. In adult patients, the %DR values were found to be in good agreement with the corresponding results obtained in the anthropomorphic adult phantom. In conclusion, on-line TCM may be considered as a valuable tool for reducing dose in routine CT examinations of pediatric and adult patients. However, the dose reduction achieved with TCM in neonates and young children was found to be lower than that obtained for adults. Therefore, on-line TCM should work as an additional means to reduce dose and should not replace other conventional means of reducing dose, especially in neonates and young children.

Abdominal aortic aneurysm: Can the arterial phase at CT evaluation after endovascular repair be eliminated to reduce radiation dose?

Conclusion: The arterial phase of computed tomography (CT) imaging is not necessary for routine detection of endoleaks. This portion of CT evaluation after endovascular AAA repair can be eliminated, with a reduction in radiation exposure. Summary: This was a retrospective analysis performed of arterial and venous phases of CT scans evaluating for endoleak in patients with endovascular repair of an abdominal aortic aneurysm (AAA). The purpose was to determine if the arterial phase of CT scanning for evaluation of endoleak can be potentially eliminated, thus lowering radiation exposure. The authors analyzed 85 patients (66 men and 19 women; mean age, 66 years) who underwent endovascular repair of an AAA. There were 110 multidetector CT examinations available for analysis. The CT protocol for endoleak evaluation included first obtaining a noncontrast, enhanced set of CT images. After this, intravenous contrast material was administered, and both arterial and venous phase images were obtained. Nonenhanced and venous phase images were evaluated to determine if an endoleak was present. Arterial phase images were analyzed separately. It was then determined how often the arterial phase imaging contributed to the diagnosis of endoleak. A total of 28 type II endoleaks were detected with a combination of nonenhanced and venous phase CT acquisitions. Of these 28 endoleaks, 25 endoleaks were also visualized during the arterial phase of the CT scan, with three type II endoleaks only seen during the venous phase. No additional endoleaks were seen with the arterial phase. Seventy-eight scans from 67 patients revealed no endoleak during the venous phase; and in these scans, no endoleaks were discovered with the arterial phase images. The arterial phase of the CT scan was responsible for 36.5% of the radiation exposure during the combination of noncontrast, venous, and arterial phase images. Comment: The radiation administered during a diagnostic CT scan is associated with low, but not zero, health risk. This radiation has been linked to an increase in life-long risk of cancer (Radiology 2004;232:735-8). Because type II endoleaks are relatively benign, the increased radiation dose of arterial phase acquisitions does not seem warranted. Additional data are required to know whether the arterial phase acquisitions may, however, remain necessary to detect small type I or type III endoleaks.

Évaluation de l’impact d’un système CAD sur la performance des radiologues pour la détection des nodules pulmonaires sur des examens scanographiques multicoupes du thorax

Objectives. Evaluate the improvement in detecting lung nodules when using multidetector CT (MDCT) computer-assisted diagnosis (CAD). Material and methods. Three radiologists (R1, R2, R3) with different levels of experience independently interpreted 30 MDCT examinations of the thorax taken for screening purposes, first without and then with CAD. The diagnosis was established by two of the three radiologists interpreting the images together, assisted by the CAD. Results. The consensus reading identified 133 nodules, 61 (46%) of which were 4 mm or larger. The sensitivity values in the detection of nodules before and after using the CAD were 54% and 80% (R1), 38% and 71% (R2), and 70% and 88% (R3), respectively. When considering only the nodules that were 4 mm or larger, the sensitivity values varied before and after using the CAD, from 62% to 95% (R1), from 41% to 84% (R2), and from 74% to 92% (R3). By combining two by two the three radiologists’ results obtained without the CAD, the sensitivity values were 65%, 83%, and 77%, respectively, for all the nodules, and 70%, 85%, and 77% for the nodules that were 4 mm or larger. The CAD induced a total of 105 false-positive results, with a mean of 3.5 per examination. Conclusion. The lung nodules missed by the radiologist can be detected if the CAD is used as a second reader. The CAD can be at least as beneficial as the use of a second independent reader.

Reliability of MDCT in Characterizing Pulmonary Venous Drainage, Diameter and Distance to First Bifurcation: An Interobserver Study

To evaluate the interobserver agreement of readers in evaluating pulmonary venous anatomy and in measuring pulmonary vein ostial diameters and distance to first bifurcation. This study was approved by our institutional review board. Thin-section contrast material-enhanced multidetector computed tomography examinations of the thorax were retrospectively reviewed in 200 consecutive patients (38 females and 162 males), age 24-79 years (mean, 52.8) referred for imaging before radiofrequency ablation therapy for atrial fibrillation. For each patient, pulmonary venous anatomy and drainage patterns including the number of venous ostia was assessed independently by experienced cardiothoracic radiologists. Pulmonary vein ostial diameter and distance to the first bifurcation of the four major pulmonary veins (right inferior and superior, left inferior and superior), the middle lobe pulmonary vein, and any anomalous pulmonary veins (common trunks and accessory veins) were measured independently at a workstation. Interreader assessment of pulmonary venous anatomy was evaluated using the Kappa statistic. Interreader variation in measurements of venous diameter and distant to first bifurcation were estimated by Bland-Altman plots and Pitman's test of difference in variance. Very good to excellent interreader agreement in detection of anomalous pulmonary venous anatomy, middle lobe pulmonary venous drainage, and other thoracic venous anomalies. No significant variation between readers in pulmonary vein ostial diameter measurements for the four major and middle lobe pulmonary veins, or the anomalous pulmonary veins. Significant interreader variability was noted in measurements of the pulmonary vein distance to first bifurcation for the right inferior (P = .017), middle lobe (P = .005), and left inferior (P = .015) pulmonary veins. There is excellent interobserver agreement when evaluating normal and anomalous pulmonary venous drainage patterns, and when measuring normal or anomalous pulmonary vein diameters. However, measurements of distances to first bifurcation were less reliable across readers.

Influence of overscanning on normalized effective doses calculated for pediatric patients undergoing multidetector CT examinations

The purpose of this study was to evaluate the effect of z overscanning on normalized effective dose for pediatric patients undergoing multidetector-computed tomography (CT) examinations. Five commercially available mathematical anthropomorphic phantoms representing newborn, 1-, 5-, 10-, and 15-year-old patients and the Monte Carlo N-Particle (MCNP, version 4C2) radiation transport code were employed in the current study to simulate pediatric CT exposures. For all phantoms, axial and helical examinations at 120 kV tube voltage were simulated. Scans performed at 80 kV were also simulated. Sex-specific normalized effective doses were estimated for four standard CT examinations i.e., head-neck, chest, abdomen-pelvis, and trunk, for all pediatric phantoms. Data for both axial and helical mode acquisition were obtained. In the helical mode, z overscanning was taken into account. The validity of the Monte Carlo results was verified by comparison with dose data obtained using thermoluminescence dosimetry and a physical pediatric anthropomorphic phantom simulating a 10-year-old child. In all cases normalized effective dose values were found to increase with increasing z overscanning. The percentage differences in normalized data between axial and helical scans may reach 43%, 70%, 36%, and 26% for head-neck, chest, abdomen-pelvis, and trunk studies, respectively. Normalized data for female pediatric patients was in general higher compared to male patients for all ages, examined regions, and z overscanning values. For both male and female children, the normalized effective dose values were reduced as the age was increased. For the same typical exposure conditions, dose values decreased when lower tube voltage was used; for a 1-year-old child, for example, the effective dose was 3.8 times lower when 80 kV instead of 120 kV was used. Normalized data for the estimation of effective dose to pediatric patients undergoing standard axial and helical CT examinations on an multidetector CT system were calculated. This data was found to depend strongly on CT acquisition mode and exposure parameters as well as patient age and sex. The effective dose from a pediatric CT scan performed in axial mode was always considerably lower compared to the corresponding scan performed in helical mode, due to the additional tissue regions exposed to the primary beam in helical examinations as a result of z overscanning.

Assessment of left ventricular function and mass in patients undergoing computed tomography (CT) coronary angiography using 64-detector-row CT: comparison to magnetic resonance imaging

To quantify left ventricular function and mass derived from retrospectively ECG-gated 64-detector-row computed tomography coronary angiography data sets in comparison to cine magnetic resonance (MR) imaging as the reference standard. We hypothesized that the administration of beta-blockers prior to multidetector computed tomography (MDCT) coronary angiography has a significant impact on left ventricular functional parameters. Multiplanar reformations in the short-axis orientation were calculated from axial contrast-enhanced CT images in 21 patients (16 male, five female; age range 41-75 years, mean 64.3+/-6.8 years) referred for CT coronary angiography. Patients whose heart rates exceeded 60 bpm received 5 mg bisoprolol orally 1 hour before the MDCT examination. In case of insufficient heart-rate reduction, up to four vials (20 mg) of metoprolol were injected intravenously. The end-diastolic volume (EDV), end-systolic volume (ESV), stroke volume (SV), ejection fraction (EF), cardiac output (CO), and left ventricular mass (LVM) of the reformatted images were analyzed compared to volumetric measurements based on continuous short-axis steady-state free-precession cine MR sequences (TR 3 ms, TE 1.5 ms, FA 60 degrees ). On average, each patient received 15.5 mg metoprolol (range 0-20 mg) and 3.85 mg bisoprolol (range 0-5 mg). The mean heart rate was 56+/-5 bpm during CT and 73+/-9 bpm during MRI examination. This difference was statistically significant (P<0.05). Mean EDV and ESV measured on MDCT were significantly higher compared to MR (MDCT vs. MR: EDV 164.2+/-52.5 vs. 144.2+/-46.7 ml, ESV 77.3+/-46.6 vs. 63.8+/-47.3 ml; P<0.05). Mean EF and CO derived from MDCT images were significantly lower compared to MR (MDCT vs. MR: EF 55.4+/-11.8 vs. 59.3+/-15.4%, CO 4822+/-779 vs. 5755+/-1267 ml; P<0.05). Mean SV and LVM were not significantly different between both methods (MDCT vs. MR: SV 86.8+/-18.1 vs. 80.3+/-15.6 ml, P = 0.44; LVM 132.4+/-42.5 vs. 138.7+/-39.1 g, P = 0.31). Left ventricular volumes assessed by the newest-generation MDCT scanners are significantly higher compared with MRI, whereas ejection fraction and cardiac output are significantly lower in MDCT. This appears to be a result of the frequent application of beta-blockers prior to MDCT examinations.

Normative Analysis of Pulmonary Vein Drainage Patterns on Multidetector CT With Measurements of Pulmonary Vein Ostial Diameter and Distance to First Bifurcation

To document the frequency of normal and anomalous drainage patterns of the pulmonary veins, and to establish normal values for pulmonary vein ostial diameters, and distance to first bifurcation using multidetector computed tomography, as pertinent to ablation procedures for atrial fibrillation. Two cardiothoracic radiologists retrospectively reviewed thin-section contrast material-enhanced multidetector computed tomography examinations of the thorax in 200 consecutive patients (38 females and 162 males), age 24-79 years (mean 52.8) referred for imaging before radiofrequency ablation therapy for atrial fibrillation. Pulmonary vein anatomy was based on both the number of venous ostia and the drainage patterns of pulmonary veins. Pulmonary vein ostial diameters and distance to first bifurcation of the four major pulmonary veins (right inferior and superior, left inferior and superior) and any additional pulmonary veins were measured at a workstation using both axial images and multiplanar reconstructions by two experienced cardiothoracic radiologists; the mean pulmonary vein diameter and the shortest distance to first bifurcation of the two measurements are reported. The majority of patients, 82% (164 patients) had four pulmonary veins, with a superior and inferior ostium on the right and a superior and inferior ostium on the left. Of the remainder, 9% (18 patients) had five veins, 4.5% (9 patients) had three veins, 3% (6 patients) had two anomalies each, and 0.5% (1 patient) had three anomalies. The middle lobe pulmonary vein drained into the right superior pulmonary vein in 83.5% of patients, directly into the left atrium in 11% of patients, and into the right inferior pulmonary vein in 5.5% of patients; 6.5% of patients had a single left pulmonary vein ostium. Mean pulmonary vein diameters with 95% confidence intervals at the ostia were as follows: right superior 17.6 (13.64-15.36) mm; left superior 16.6 (16.03-17.08) mm; right inferior 17.1 (16.58-17.55) mm; left inferior 14.8 (14.25-15.27) mm, and independent middle lobe 8.6 (8.27-8.86) mm. Mean distance to first bifurcation with 95% confidence intervals were: right superior 14.5 (17.02-18.23) mm; left superior 17.6 (16.63-18.53) mm; right inferior 7.0 (6.49-7.46) mm; left inferior 13.5 (12.83-14.16) mm, and independent middle lobe 8.4 (7.7-9.17) mm. Thin-section thoracic computed tomography demonstrates a greater variability of pulmonary venous drainage than previously described. There is greater variability of the right lung venous drainage compared to the left lung. Eighty-two percent of people have four standard pulmonary veins. There is significant variability in pulmonary vein diameter and distance to first bifurcation.

Thin-section axial multidetector computed tomography and multiplanar reformatted imaging of children with suspected foreign-body aspiration: is virtual bronchoscopy overemphasized?

To determine the added value of multidetector computed tomography (MDCT)-assisted virtual bronchoscopy (VB) to axial MDCT and multiplanar reformatted (MPR) imaging with respect to conventional bronchoscopy in the evaluation of children with suspected foreign-body aspiration (FBA). Twenty-one consecutive children (14 male, seven female, age 8 months-7 years, mean age 3.5 years) presenting with the suspicion of FBA were examined with 16-slice MDCT using 100-120 kV, 30-50 mA, 1-mm section thickness, 1.2 pitch ratio, and 0.6-1.0-mm reconstruction interval. Before CT examinations, chest radiographies were also obtained in all cases. VB and MPR imaging were carried out after MDCT examinations. Nine foreign bodies were identified by gold-standard conventional bronchoscopy. VB, thin-section axial MDCT, and MPR images identified eight of nine foreign bodies. CT scans with MPR images and VB did not reveal a chronic foreign body; and, in one patient, endobronchial mucous was diagnosed as the foreign body. The sensitivity, specificity, and accuracy of thin-section axial MDCT and MPR images alone in the diagnosis of FBA were 88.9%, 91.7%, and 90.5%, respectively. Results were the same as those obtained when VB was also included. MDCT with VB and axial/MPR images provide equally valuable information in children with suspected foreign-body aspiration and prevent unnecessary conventional bronchoscopic examinations. However, VB increases total examination time and cost, and it does not provide additional information over MPR images in the evaluation of foreign-body aspiration.

Coronary imaging quality in routine ECG-gated multidetector CT examinations of the entire thorax: preliminary experience with a 64-slice CT system in 133 patients

To evaluate image quality in the assessment of the coronary arteries during routine ECG-gated multidetector CT (MDCT) of the chest. One hundred and thirty three patients in sinus rhythm underwent an ECG-gated CT angiographic examination of the entire chest without beta-blockers with a 64-slice CT system. In 127 patients (95%), it was possible to assess the coronary arteries partially or totally; coronary artery imaging failed in six patients (5%), leading to a detailed description of the coronary arteries in 127 patients. Considering ten coronary artery segments per patient, 75% of coronary segments were assessable (948/1270 segments). When the distal segments were excluded from the analysis (i.e., seven coronary segments evaluated per patient), the percentage of assessable segments was 86% (768/889 proximal and mid coronary segments) and reached 93% (474/508) when assessing proximal segments exclusively. The mean number of assessable segments was significantly higher in patients with a heart rate < or =80 bpm (n=95) than in patients with a heart rate >80 bpm (n=38) (p<0.002). Proximal and mid-coronary segments can be adequately assessed during a whole-chest ECG-gated CT angiographic examination without administration of beta-blockers in patients with a heart rate below 80 bpm.

MDCT in the evaluation of skeletal trauma: principles, protocols, and clinical applications

Multidetector computed tomography (MDCT) scanners have made volume imaging possible and are used extensively to study polytrauma patients, especially in the evaluation of the spine and peripheral skeleton. An MDCT scanner coupled with a modern workstation has become an essential diagnostic tool for any emergency department. Familiarity with the basic physical principles of MDCT such as projection data, section collimation, and beam collimation is important to achieve high-quality imaging while keeping unnecessary radiation to a minimum. After a polytrauma MDCT examination, images can be reconstructed to obtain different slice thickness, slice interval, fields of view, or reconstruction kernels. No additional scanning is needed for imaging the thoracolumbar spine or bony pelvis. High-quality multiplanar reformation (MPR) and three-dimensional (3-D) images can be created at the workstation using the volumetric data. However, MDCT is a high-dose examination, and care should be taken to use as low a dose as possible. In the musculoskeletal system, MDCT has long been used for evaluation of spinal and pelvic trauma; however, the frequency of its use in extremity trauma has been low. In the extremities, radiography seems to underestimate the extent and severity of injury, especially in complex areas such as the shoulder, elbow, wrist, knee, and ankle. MDCT in the extremities is helpful in fracture detection, evaluation, characterization, and treatment planning. The MPR images give excellent structural detail, and the 3-D images help in understanding the spatial relations, which is important for fracture classification and for preoperative planning. MDCT is also helpful in the follow-up of postoperative results, even in the presence of hardware. Tendon injuries can also be evaluated with MDCT.

Global and Regional Left Ventricular Function Assessment with 64-Slice MDCT in Heart Failure Patients: A Comparative Study with Echocardiography

Background: Sixty-four slice multi-detector computed tomography (MDCT) with enhanced temporal resolution may permit reliable evaluation of left ventricular (LV) function. Accuracy of global and regional LV function; dimensions and wall thickness assessment with 64-slice MDCT in heart failure patients is not known. The aim of this study is to compare 64-slice MDCT with echocardiography to assess LV function in these patients. Methods: Twenty-five patients with ejection fraction (EF) < 45% who underwent 2D-echocardiography and MDCT examinations for clinical indications were assessed.

Esophageal injuries: Spectrum of multidetector row CT findings

Background Aim of this study is to illustrate the multidetector row computed tomographic findings related to oesophageal injuries and their significance for therapeutic decisions. Method From April 2002 to April 2005 we studied 16 patients with suspected oesophageal injury. Ten patients underwent standard chest radiograph, while five patients with suspected foreign body ingestion were submitted to cervical plain film and gastrografin swallow study. All 16 patients underwent multidetector row CT examination. Results In six patients with cervical, thoracic and abdominal trauma, CT showed the presence of thoracic traumatic lesions and findings suggestive of perforation of the oesophagus. In five patients with foreign body ingestion cervical radiography was positive in only one case, while CT showed the presence of a foreign body in all cases. In three patients with post-intubation complications, CT showed the presence of perioesophageal fluid collection containing small gas bubbles in two cases and an oesophageal-aortic fistula in one case. In the remaining two patients with suspected spontaneous oesophageal perforation, CT demonstrated an oesophageal wall oedema and thickening in one case, and oesophageal fluid distension with perioesophageal small bubbles gas and fluid in the second case. Conclusion Oesophageal injuries, when complicated with perforation, constitute a life-threatening condition. Knowledge of the CT signs of oesophageal injuries has important implications for the role of imaging at the time of initial diagnosis.

Myocardial enhancement pattern in patients with acute myocardial infarction on two-phase contrast-enhanced ECG-gated multidetector-row computed tomography

To evaluate the myocardial enhancement pattern of the left ventricle on two-phase contrast-enhanced electrocardiogram (ECG)-gated multidetector computed tomography (MDCT) images in patients with acute myocardial infarction (AMI). Two-phase contrast-enhanced ECG-gated MDCT examinations were performed in 16 patients with AMI. The presence, location and pattern of myocardial enhancement were evaluated. MDCT findings were compared with the catheter angiographic results. Subendocardial (n = 9) or transmural (n = 6) area of early perfusion defects of the myocardium was detected in 15 of 16 patients (94%) on early-phase CT images. Variable delayed myocardial enhancement patterns on late-phase CT images were observed in 12 patients (75%): (1) subendocardial residual perfusion defect and subepicardial late enhancement (n = 6); (2) transmural late enhancement (n = 1); (3) isolated subendocardial late enhancement (n=1); and (4) isolated subendocardial residual perfusion defect (n = 2). On catheter angiography, 14 of 15 corresponding coronary arteries showed significant stenosis. Variable abnormal myocardial enhancement pattern was seen on two-phase, contrast-enhanced ECG-gated MDCT in patients with AMI. Assessment of myocardial attenuation on CT angiography gives additional information of the location and extent of infarction.

Liver Metastases on Serial Contrast-enhanced Multidetector Computed Tomography Examinations

To verify the earliest detectability of liver metastases in patients who underwent serial multidetector computed tomography (MDCT) examinations. We selected 12 patients with known primary cancer who underwent 4 or more contrast-enhanced, 4-detector MDCTs. When metastases had been reported, an evaluation of the preceding MDCT was done to define whether the lesion was detectable, detectable only by minimal signs, undetectable, or detected but misdiagnosed as a benign lesion (MBL). Eighty-eight lesions were analyzed. Evaluating the preceding examination, we defined detectable (n=8), detectable only by minimal signs (n=5), undetectable (n=74), and MBL (n=1). The group with minimal signs was composed of 4 small hypodense foci and 1 calcification. The MBL was a non-Hodgkin lesion first misdiagnosed as a hemangioma. Approximately 15% of liver metastases were prospectively missed, 9% of them being retrospectively detectable, 6% being retrospectively visible as minimal signs, whereas only 1% of liver metastases were misdiagnosed as a benign lesion.

Nonvascular Complications in Pediatric Liver Recipients: Multidetector Computed Tomography Evaluation

In pediatric liver transplantation postoperative diagnosis of complications is crucial for graft salvage. Multidetector computed tomography (MDCT) is a technique to evaluate complications. In this study we present nonvascular abdominal complications encountered in pediatric recipients after liver transplantation. We retrospectively examined 113 MDCT examinations in 43 pediatric patients who underwent liver transplantation between 1997 and 2005. Computed tomography (CT) examinations were made by a 16-detector multislice CT scanner. The pathological findings on CT images were: intraperitoneal free fluid, intrahepatic bile duct dilatation, graft liver infarction, perihepatic and intraperitoneal fluid collections (six biloma), colonic and/or intestinal dilatation, splenic infarction, perihepatic hematoma, right adrenal hemorrhage, perihepatic abscess, incisional hernia, intrahepatic biloma and periportal collar. In one patient intestinal hemorrhage was suspected. Intestinal perforation was suspected in three patients. Among these three patients, one patient died before any surgical intervention. In two patients the diagnosis was confirmed at surgery. In pediatric patients, the short examination time, brief sedation duration, and high-resolution images make MDCT an effective radiological method to evaluate nonvascular transplant complications.

Usefulness of Multidetector Computed Tomography for the Initial Assessment of Blunt Abdominal Trauma Patients

The prompt detection and accurate localization of abdominal injuries are difficult. Some diagnostic modalities, including laboratory tests, ultrasound, and diagnostic peritoneal lavage (DPL) were used to evaluate patients with blunt abdominal trauma, with various advantages and pitfalls. We aimed to evaluate the risk and benefit of using multidetector computed tomography (MDCT) as an initial assessment tool for proper diagnosis and treatment planning of patients with blunt abdominal trauma. Two hundred fifty-two patients with blunt abdominal trauma were prospectively enrolled. Multidetector computed tomography was performed during resuscitation. The risk and benefit of using MDCT in the diagnosis and planning of treatment were analyzed. The time required for a MDCT examination averaged 10.2 minutes. Of the studies done, 224 revealed abdominal injuries. Of those, 34 were performed in patients with unstable hemodynamic status without adverse effect. Prompt diagnosis and proper treatment were given according to the MDCT findings. A total of 43 (17.1%) MDCTs showed contrast extravasation. Active bleeding was confirmed in all and treated with transarterial embolization (30) or surgery (13). Another 58 patients sustained bowel, mesenteric, or pancreatic injuries (BMPI) necessitating laparotomy. The sensitivity, specificity, and accuracy of MDCT in identifying patients with active bleeding or BMPI were all 100%. Multidetector computed tomography was useful as a second line initial assessment tool to identify injuries and determine treatment planning in blunt abdominal trauma patients. No increased risk was found if the facility is readily available, the protocol is well designed, and the patient is well prepared.

Four cases of accessory cardiac bronchus incidentally detected on multi-detector CT

Accessory cardiac bronchus (ACB) is a rare bronchial anomaly. There have been many recent reports concerning CT diagnosis. Here, we assessed the frequency of ACB in our routine multi-detector CT examinations of the chest and presented several CT features. ACB was observed in four of 605 cases, representing a frequency of 0.66%. The origin of ACB was the medial wall of the intermediate bronchus in all cases. A normal B7 was identified in all cases. The inner diameter of ACB was 5.5–8.6 mm, and the length was 7.5–13.5 mm. The end of the ACB was blind in two cases. Both proper lobule and interlobar fissure were found in one case. Abnormal vessels were not identified in any cases. In all patients, MPR, MPVR, volume rendering and virtual endoscopy were performed. The ACB was demarcated by a spur at the origin in all cases. With the exception of one patient, none presented with symptoms related to ACB. No ACB was identified prospectively. Careful interpretation of the results of chest CT examination is required in patients with respiratory symptoms.

Acute knee trauma: analysis of multidetector computed tomography findings and comparison with conventional radiography

To evaluate the multidetector computed tomography (MDCT) findings of acute knee trauma and to compare radiography with MDCT in patients referred to a level 1 trauma center. During a 5-year period, a total of 415 MDCT examinations were performed on 409 patients with acute knee trauma to reveal complex fracture anatomy or rule out a fracture. MDCT and primary radiographs were re-evaluated with respect to fracture location and trauma mechanism. Tibial plateau fractures were further analyzed depending on anatomical location: anterior-medial, anterior-lateral, posterior-lateral, and posterior-medial regions. Maximal depression of the tibial articular surface was measured. Findings on the primary knee radiographs were compared with MDCT findings. Of the 409 patients, 356 (87%) had a knee fracture. A total of 451 fractures were found in all anatomic regions: distal femur (n=49), proximal tibia (n=307), patella (n=23), and proximal fibula (n=72). Primary radiographs were available in 316 (76%) cases. Of these, 225 (71%) had MDCT in order to reveal the fracture anatomy better, and 91 (29%) had a subsequent MDCT after negative plain radiographs. Overall sensitivity of radiography was 83%, while negative predictive value was 49%. On radiography, tibial plateau articular depression was underestimated in all regions except when the fracture consisted of the whole half of the anterior or posterior plateau. The three main injury mechanisms were traffic accident, a simple fall, and sport. In 49 cases (15%), primary radiographs were suboptimal due to positioning. In severely injured patients, diagnostically sufficient radiographs are difficult to obtain, and therefore a negative radiograph is not reliable in ruling out a fracture. In these patients, MDCT is a fast and accurate examination and is also recommended in patients with tibial plateau fractures or complex knee injuries in order to evaluate the fracture adequately.

Comparison of the Image Quality on Low-dose Urinary Tract Multidetector CT Examinations with 80 kVp and 120 kVp (Original Research)

Purpose: To compare the image quality on low-dose urinary tract multidetector CT examinations with 80 kVp and 120 kVp. Materials and Methods: Seventy-six patients with urinary tract symptoms were evaluated for urinary tract calculi by unenhanced multidetector CT. The examinations were performed with a four-row detector CT scanner. In all patients, two low-dose CT examinations with different kVp and mAs values (120 kVp, 30 mAs and 80 kVp, 95 mAs) were performed. The other scanning parameters were kept constant. Weighted-CT dose index was equal in both examinations. Both CT examinations were quantitatively compared with calculating the HU values of kidneys, subcutaneous fat, calculus, and phleboliths and the HU ratio of urinary calculi to the kidney. Both scans were also qualitatively compared for image quality of upper and lower abdomen. Results: One hundred and two calculi were detected in 50 of 76 patients. One or more phleboliths were present in 20 patients. HU values of the phleboliths and urinary calculi were higher on images obtained with 80 kVp than those obtained with 120 kVp. HU ratio of the calculi to the kidney was higher on scans with 80 kVp. Adipose tissue was less noisy and had lower HU value on 80 kVp images. Image quality of the upper abdomen and major pelvis were better on 80 kVp images, and the majority of these patients were normal (n=28) and overweight (n=20). Minor pelvis mostly (60%) revealed poorer image quality on 80 kVp images. However, the majority were overweight (n=22) or obese (n=6). In patients with osteoporosis, image quality was relatively better when compared with similar weighed patients without osteoporosis on 80 kVp images. Small renal, proximal and middle ureteral calculi were better demarcated on 80 kVp images. Conclusion: Low-dose urinary tract multidetector CT examination with 80 kVp, compared to 120 kVp provides better image quality in the upper abdomen and major pelvis. In overweight and obese patients, minor pelvis may not be evaluated thoroughly on 80 kVp images. Detection of small renal, proximal and middle ureteral calculi could be improved by using 80 kVp setting. Keywords: urinary calculi, low-dose multidetector ct, lower kilovoltage, 80 kvp