mL Of Contrast Agent Research Articles

Blunt craniocervical artery injury in cervical spine lesions: the value of CT angiography

The awareness of traumatic craniocervical artery injuries has increased over the last years, and the detection rate varies in published trauma series. These injuries are often associated with cervical spinal and cranial trauma. The purpose of this prospective study was to determine the frequency and injury characteristics of blunt traumatic cervical artery injuries in patients suffering from cervical spine injuries by using a standardized CT angiography (CTA) protocol of the craniocervical vessels. Over a period of 32 months (February 2006 to September 2008), we prospectively evaluated 53 patients with osseous cervical spine injuries. Of these, 41 patients were screened for blunt craniocervical vessel injuries using CT angiography in 718 consecutive patients requiring a whole-body trauma CT due to the mechanism of their injury and injury patterns. All examinations were performed using a 16-row multi-slice computed tomography (Sensation 16, Siemens, Erlangen, Germany). Initially, a scan of the neurocranium angulated in orbito-meatal orientation was acquired. Then, a CT angiography of the craniocervical vessels with 40 ml of iodinated contrast agent (flow 4 ml/s; 40 ml saline flush, flow 4 ml/s) was performed starting at the level of Th2 up to the roof of the lateral ventricles. The scan was started using bolus tracking. Finally, a contrast-enhanced spiral thoraco-abdominal scan was performed with a delay of 20 s after administering a second contrast bolus of 60 ml. Besides, 11 patients with already detected isolated cervical spine injury, who were not initially involved in the whole-body trauma imaging protocol, underwent a secondary CT angiography with 60 ml of contrast agent (flow 4 ml/s; 40 ml saline flush, flow 4 ml/s), starting at the level of Th2 up to the roof of the lateral ventricles. The craniocervical vessels were analyzed in the source images, with the use of maximum-intensity projections and curved multi-planar reconstructions. Alternatively, a duplex ultrasound (DUS) was performed in one patient with respect to pregnancy. CTA was considered adequate for diagnosis in all but one case due to reduced CTA imaging quality. In one patient, DUS instead of CTA was performed with respect to pregnancy. We detected isolated osseous cervical spine injury in 53 consecutive patients. Of these patients, 18.9% suffered from vertebral artery injuries (VAI) (14 VAI in 10 patients). Carotid artery injuries were not detected in these patients. In five (50%) patients, we observed cerebral infarction due to VAI. Craniocervical vessel injury is a life-threatening and underdiagnosed event in cases of cervical spine injury. CTA of the craniocervical vessels offers a fast, safe, and feasible method for detecting vascular injuries of the craniocervical region and allows prompt further treatment if necessary to reduce the risk of cerebral infarction. CTA of the craniocervical vessels is strongly indicated in cases of cervical spine trauma and in trauma mechanisms involving the cervical spine. Our data underscore the need for screening of blunt carotid and vertebral injury especially in injured cervical spine.

413 DOES THE POSTOPERATIVE PLACEMENT OF A URETERAL STENT LEAD TO A REFLUX IN THE UPPER URINARY TRACT?

You have accessJournal of UrologyUrothelial Cancer: Upper Tract Tumors1 Apr 2010413 DOES THE POSTOPERATIVE PLACEMENT OF A URETERAL STENT LEAD TO A REFLUX IN THE UPPER URINARY TRACT? Gunnar Wendt-Nordahl, Patrick Honeck, and Thomas Knoll Gunnar Wendt-NordahlGunnar Wendt-Nordahl More articles by this author , Patrick HoneckPatrick Honeck More articles by this author , and Thomas KnollThomas Knoll More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2010.02.483AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Endoscopic treatment of superficial transitional cell carcinoma of the upper urinary tract offers an alternative to nephroureterectomy in selected cases. The postoperative instillation therapy (e.g. with mitomycin C) is postulated to reduce the recurrence rate. A proposed application mode is placing an ureteral stent after the procedure and instillating the substance in the bladder. Via a vesico-ureteral reflux (VUR) an effect in the upper urinary tract is postulated. Aim of our study was to determine the occurrence of a VUR after placement of an ureteral stent. METHODS 12 consecutive patients receiving an ureteral stent after ureterorenoscopic stone treatment were instillated with 50ml of contrast agent in the empty bladder. After radiologic check for a VUR, additional 200ml were instillated and another radiologic check for VUR was performed. The same experiment was repeated on postoperative day one. RESULTS None of the patients displayed a VUR after the instillation of 50ml contrast agent. After instillating 250ml a VUR could be observed in 6/12 patients. The results were confirmed in the experiments performed one day later. CONCLUSIONS Despite the placement of an ureteral stent, instillation of volumes under 50ml did not lead to a VUR. Therefore, the instillation therapy of volumes <50ml does not seem effective. Dilution to 250ml leads to a reflux in 50% of the patients. However, the effect of such a diluted instillation therapy is not known. Sindelfingen, Germany© 2010 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 183Issue 4SApril 2010Page: e163 Advertisement Copyright & Permissions© 2010 by American Urological Association Education and Research, Inc.MetricsAuthor Information Gunnar Wendt-Nordahl More articles by this author Patrick Honeck More articles by this author Thomas Knoll More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

Simulated Low-Dose Computed Tomography in Oncological Patients

Image quality of chest and abdominal computed tomographic (CT) scans was evaluated at different doses to assess the lowest value of x-ray dose at which the image quality was not being affected. Using multislice CT (MSCT), 29 patients who submitted to follow-up examinations were examined using a combined MSCT protocol of the chest and the abdomen on 4-raw MSCT (Siemens, Erlangen, Germany). For each examination, approximately 120 mL of contrast agent (Bracco-Altana, Konstanz, Germany) was applied intravenously. The raw data were transferred to an external personal computer equipped with an image reconstruction software (CardioRecon 6; Siemens, Forchheim, Germany) to simulate 5 different dose levels. To simulate them correctly, a milliampere second-dependent noise was added to every image, so that the changes in a current-time product could be imitated. The images were compared in consensus by 2 radiologists who were not informed about the technical scanning parameters, that is, dose parameters, and were graded in 4 different subcategories on a 1-to-5-point scale. For statistical analysis, the Friedman test was used. Additional evaluations for lesions smaller than 1.0 cm were performed and analyzed separately. For image noise, there was a significant change between 40 and 60 mA s. For lesion detection, there was no significant change. The contour of the small objects did not differ between 90, 60, and 40 mA s. However, a dose reduction to 30 mA s had a significant effect. The contrast did not differ between 90, 60, 40, and even down to 30 mA s. Only a maximal dose reduction to 20 mA s had a significant effect on the contrast. The level of noise was most sensitive to the current. Whereas a dose reduction to 60 mA s did not yet have a significant effect, there was a significant increase of noise at 40 mA s. The MSCT can be applied with a lower dose than that usually selected in examinations at present to follow-up and stage the oncological patients adequately.

TH‐C‐304A‐09: Semi‐Automatic Respiratory Motion Correction for Liver CT Perfusion

Purpose: To develop and validate a semi‐automatic algorithm for correcting respiratory motion in a free breathing dynamic CT scan for perfusion imaging. Method and Materials: The CT perfusion protocol allowed the patients to breath freely, imaging two adjacent 4 cm volumes of liver alternatingly using the axial shuttle mode. Each 4 cm section was imaged 40 times during 2 minutes with 30–40 ml of contrast agent injected at a rate of 4 ml/s beginning approximately 10 seconds into the scan. A semi‐automatic algorithm has been implemented to sort the reconstructed CT images. One reference image from each 4 cm section is selected and several 40×40 voxels regions of interest are placed around the edge of the liver to create a binary mask. Every image in the scan was then filtered with the binary mask and cross‐correlated with the reference image ‐ with the maximum correlation coefficient indicating the best match. The method was first validated using a motion phantom with both sinusoidal and irregular breathing patterns. The method has also been applied to15 patient scans ‐ with manual sorting based on contour matching being the gold standard. Results: For the sinusoidal motion phantom, the algorithm reproduced the predicted period and amplitude. In the phantom study with irregular breathing‐pattern the algorithm matched the manual sorting within ±1.25 mm. The automatic algorithm matched the gold standard within ±2.5 mm in 91% of all images in patient scans. In patient‐scans with detected peak‐to‐peak breathing amplitude of 15 mm or less the algorithm matched the manual sorting within ±2.5 mm in 93% of cases. Conclusions: The semi‐automatic respiratory motion correction algorithm has been validated in motion phantom scans and 15 patient‐scans. The algorithm improved sorting efficiency significantly, reducing a typical sorting time from 2 hours to less than 6 minutes per patient.

Erste Erfahrungen mit der sequenziellen, prospektiv getriggerten CT-Koronarangiografie an einem 128-Schicht-Computertomografen

Spiral CT angiography (CTA) of the coronaries using low-pitch scanning and ECG-gated image reconstruction is a robust method for detecting or excluding relevant coronary plaque. However, the resulting dose exposure is considerable. The aim of the present study was to evaluate image quality and artifacts as well as to record dose values for sequential coronary CTA using a 128-slice scanner with a temporal resolution of 150 ms. 20 patients with a regular heart rate and without contraindications for oral/I.V. beta blockers, who were referred for CTA of the coronaries for exclusion or detection of relevant plaques, were examined by sequential CTA with the following parameters: 120 kV, 200 ref mAs, collimation 2 x 64 x 0.6, table feed of 34.5 mm at a detector width of 38.4 mm. A total acquisition time of 380 ms per table position allowed for mild shifting of the reconstruction window within the cardiac cycle of +/- 5 %. 50 ml of contrast agent were injected at 5 ml/s followed by a 50 ml split bolus (20 % contrast). The individual start delay was determined by a test bolus scan (10 ml contrast + 50 ml saline flush at 5 ml/s). The image quality for each segment, coronary artery, and patient was determined on a 4-point scale. Dose values were estimated based on the individual dose length product as provided by the scanner's patient protocol. Artifacts were evaluated to determine the cause (calcium vs. motion). All patients received beta blocker pretreatment. The mean heart rate was 62 +/- 5 beats/min. 5 % (13 / 286) of all segments in 5 / 20 patients were rated as non-diagnostic. The mean dose length product was 213 mGy x cm, and the mean effective dose was 3.6 mSv. Calcifications were the major cause of non-diagnostic images. However breathing or other motion artifacts occurred as well. In select patients with effective heart rate control and thorough instruction for breath hold compliance, sequential CTA of the coronaries using a 128-slice scanner with a temporal resolution of 150 ms is technically feasible. The resulting effective dose values are clearly below those of spiral coronary CT scans.

Assessment of the hepatic microvascular changes in liver cirrhosis by perfusion computed tomography

To assess the hepatic microvascular parameters in patients with liver cirrhosis by perfusion computed tomography (CT). Perfusion CT was performed in 29 patients without liver disease (control subjects) and 39 patients with liver cirrhosis, including 22 patients with compensated cirrhosis and 17 patients with decompensated cirrhosis, proved by clinical and laboratory parameters. CT cine-scans were obtained over 50 s beginning with the injection of 50 mL of contrast agent. Hepatic microvascular parameters, mean transit time (MTT) and permeability surface area product (PS) were obtained with the Perfusion 3 software (General Electric, ADW 4.2). The overall differences of MTT and PS between control subjects, patients with compensated cirrhosis and those with decompensated cirrhosis were statistically significant (P = 0.010 and P = 0.002, respectively). MTT values were 15.613 +/- 4.1746 s, 12.592 +/- 4.7518 s, and 11.721 +/- 4.5681 s for the three groups, respectively, while PS were 18.945 +/- 7.2347 mL/min per 100 mL, 22.767 +/- 8.3936 mL/min per 100 mL, and 28.735 +/- 13.0654 mL/min per 100 mL. MTT in decompensated cirrhotic patients were significantly decreased compared to controls (P = 0.017), whereas PS values were remarkably increased (P = 0.001). The hepatic microvascular changes in patients with liver cirrhosis can be quantitatively assessed by perfusion CT. Hepatic microvascular parameters (MTT and PS), as measured by perfusion CT, were significantly altered in decompensated cirrhosis.

Angio-tomografía computarizada multidetector en el estudio del aneurisma de aorta abdominal. Comparación de tres volúmenes de contraste diferentes

To prospectively and quantitatively compare the use of different volumes of contrast in 16-slice CT angiography for the study of aneurysms of the abdominal aorta before and/or after treatment. From November 2005 to March 2006, we included 63 consecutive patients referred for CT angiography for aneurysm of the abdominal aorta or for post-treatment follow-up. Each patient was randomly assigned to one of three groups: group A was administered 100 mL of contrast agent, group B 80 mL, and group C 60 mL. In all cases, contrast was administered with 40 mL of physiological serum at a rate of 4 ml/s. A 16-detector CT scanner was used. In the last 61 patients, attenuation was measured in different locations using circular ROIs. Hounsfield units were recorded in the first slice (initial contrast), in the last slice (final contrast), at their maximum value, and also at one-second intervals. No statistically significant differences in the Hounsfield units recorded in the first slice, in the last slice, or in the maximum values were found between the different groups. Mean values were above 200 in 58 of 61 patients. Weight and body mass index (BMI) were negatively correlated with aortoiliac attenuation. Using a 16-detector CT scanner enables the volume of contrast for studies of aneurysms of the abdominal aorta to be reduced considerably; however, 60 mL might not be sufficient for patients with high weight or BMI.

Demonstration of clinically silent plaque rupture by dual-source computed tomography

A 69-year-old woman was admitted because of atypical chest pain. She had hyperlipidaemia and diabetes. ECG and echocardiography showed no abnormal finding. Noninvasive coronary angiography was performed using dual-source computed tomography (DSCT; Somatom Definition, Siemens Medical Solution, Forchheim, Germany). 70 ml of contrast agent was used at 5 mL/s. The collimation was 2 × 64 × …

Noninvasive imaging of the coronary arteries using a 64-row multidetector CT scanner: initial clinical experience and radiation dose concerns

We present our initial clinical experience with a recently introduced 64-detector computed tomography (64-MDCT) scanner that makes use of a periodic motion of the focal spot in the longitudinal direction (z-flying focal spot), which enables it to reach a final spatial resolution of 0.4 x 0.4 x 0.4 mm(3) and a temporal resolution of 83 ms. A total of 114 patients (108 men, six women; age range 36-77 years, mean 63.1 years) underwent retrospective electrocardiogram (ECG)-gated examination of the coronary arteries using a 64-MDCT scanner (Somatom Sensation 64, Siemens Medical Solutions, Germany). Acquisition parameters were the following: collimation 64 x 0.6 mm, 800 quality reference milliampere second (mAs), 120 kVp, 0.33-s gantry rotation time and pitch 0.2. Images were acquired in all cases after i.v. administration of 80 ml of contrast agent (Iomeron 400 mgI/dl, Bracco, Italy) + 30 ml of saline at 4 /s and delay time determined using a bolus triggering technique. Oral betablockers were administered to patients with heart rate (HR) >75 bpm. To reduce radiation exposure, an automatic exposure control system was applied in all cases to adapt tube current to patient size and anatomic shape (CARE Dose 4D, Siemens Medical Solutions, Germany). The optimal temporal window for raw data reconstruction was chosen from an initial preview of images reconstructed with different phase settings (range 0%-95% RR interval with 5% gap) at a selected anatomical level in the mid part of the right coronary artery. CT dose index volume and effective dose were quantified in all patients using dedicated software. Mean HR recorded during image acquisition was 65.6+/-19.2 bmp (range: 44-96 bmp), and beta-blockers were administered to 16/114 patients (14.0%). Technical adequacy was achieved in all patients but two (2/114; 1.7%). In patients with HR <60 bmp, the best reconstruction intervals were identified in the end-systolic (30%-35% of the RR interval) and end-diastolic (60%-65% of the RR interval) phases; with faster HR (>80 bmp), high image quality was observed in end-systole (30%-35% of the RR interval). Mean CT dose index (CTDI) volume was 36.53+/-8.30 mGy per patient. In comparison with a conventional examination with fixed mAs, the use of the CARE Dose 4D system provided a 33.3% CTDI volume reduction (p<0.001). Mean effective dose was 9.5+/-3.4 millisievert (mSv) per patient (range 7.1-17.7). The 64-MDCT scanner diagnostic performance for coronary CT angiography is further improved with better spatial and temporal resolution and faster scan times; besides, initial clinical results are promising. The use of dose-reducing acquisition techniques is mandatory to limit radiation exposure to the patient.

Feasibility and Optimization of Aortic Valve Planimetry with MDCT

The aortic valve can be assessed using MDCT; however, measurements of the aortic opening area vary with the cardiac cycle. In this study, we sought to assess the optimal timing for measuring the area of the aortic opening with MDCT. Retrospectively gated MDCT was performed in 57 patients with the following parameters: gantry rotation time, 420 milliseconds; tube voltage, 120 kV; tube current, 550 mAs with tube current modulation; and slice collimation, 16 x 0.75 mm. From 72 to 100 mL of contrast agent (320 g/mL3) was injected i.v. at 4-5 mL/s. High-resolution data sets were obtained for planimetry at phase starts of 0, 50, 100, 150, and 200 milliseconds after the R wave peak and were assessed for aortic opening area and the presence of artifacts. In 41% of patients, the cardiac phase with the largest aortic opening area was at 50 milliseconds after the R wave peak. The area of the aortic opening measured at 0 milliseconds after the R peak was 2.7 +/- 0.8 cm2 (mean +/- SD); at 50 milliseconds, 2.9 +/- 0.2 cm2; at 100 milliseconds, 2.9 +/- 0.7 cm2; at 150 milliseconds, 2.8 +/- 0.7 cm2; and at 200 milliseconds, 2.4 +/- 0.8 cm2. The image quality was best at 50 milliseconds after the R peak in 42% of patients, 100 milliseconds in 29%, 150 milliseconds in 20%, 0 milliseconds in 7%, and 200 milliseconds in 2%. The aortic valve appeared closed in three patients at 0 milliseconds and in four patients at 200 milliseconds. Fewer artifacts were present in the midsystolic phases (i.e., 50-150 milliseconds) ("double-leaflet" artifact, 5-13%; "incomplete contour" artifact, 20-26%) than in the early (0 milliseconds) and late (200 milliseconds) systolic phases (double-leaflet artifact, 38% and 43% of patients; incomplete contour artifact, 76% and 73%, respectively). Aortic valve planimetry is best performed at phase starts of 50-100 milliseconds after the R peak because the area of the aortic opening is widest and image quality is best at that phase.

Comparison of Reconstruction Intervals in Routine ECG-Pulsed 64-Row-MSCT Coronary Angiography in Frequency Controlled Patients

In light of the increasing use and acceptance of multislice computed tomography (MSCT) coronary angiography it was the purpose of this study to compare reconstruction intervals used in a routine ECG-pulsed MSCT coronary artery angiography setting with frequency controlled patients. Examinations were performed on a Siemens Somatom Sensation 64 scanner with a total of 110 ml of contrast agent and ECG pulsing (interval from 40% to 70%) after oral application of a beta-blocker if the heart rate was higher than 65 bpm. All human subjects were referred for the evaluation of suspected coronary artery disease. Coronary artery segments were evaluated by two experienced radiologists in a consensus reading. A ranking of diagnostic image quality (from 1 (no evaluation possible) to 5 (excellent image quality)) was statistically evaluated by Wilcoxon Signed Rank Test. In 45 patients (30 male, 15 female, age 63.8 +/- 12.1 years) we detected a significant advantage of the 60% reconstruction interval over 40%, 50%, and 70% (for each p < 0.05). In cases of sudden arrhythmia or movement during the scan, additional reconstruction intervals within the ECG-pulsed reconstruction intervals remained necessary for diagnosis. In a routine diagnostic setting with frequency controlled patients and ECG pulsing the 60% reconstruction interval can be considered superior for the initial diagnosis in 64-row multislice computed tomography coronary angiography. However, further information can be derived from various reconstruction intervals such as 40% and 70%.

Visualization of peripheral pulmonary artery stenosis using high-resolution multidetector computed tomography

Vascular Medicine 2005; 10 : 235Ð236© 2005 Edward Arnold (Publishers) Ltd 10.1191/1358863x05vm613xxA 3-year and 9-month-old patient (7.1 kg) withpulmonary atresia, ventricular septal defect and multifo-cal lung perfusion with major aorto-pulmonary collat-eral arteries (MAPCA) had shunt implantationconnecting the hypoplastic central pulmonary arteriesto the aorta (Panel A; S Shunt, AAo ascendingaorta, RPA right pulmonary artery, LPA left pul-monary artery, RLLB right lower lung branch). Postoperatively the right upper lung was hyperperfuseddue to MAPCA, which was occluded interventionally inthe catheterization laboratory. Unfortunately the patientcould not be weaned off the ventilator due to persistenthyperperfusion of the right upper lung and hypoperfu-sion of the right lower lung.The arterial and venous vascular system was visual-ized with multidetector computed tomography (MDCT,Panels A and B). After venous injection of 17 ml of con-trast agent (Imeron 400) the neck, thorax and the upperabdomen were imaged within 10 seconds with nearlyisotropic voxels (Somatom Sensation, 16 detectors,collimat ion 0.75 mm, 80 kV, 98 eff. mAs, voxelsize0.5 0.5Tuebingen, Hoppe-Seyler-Strasse 1, 72076 Tuebingen, Germany. 0.6 mm

Multislice spiral computed tomographic angiography of coronary arteries in patients with suspected coronary artery disease: An effective filter before catheter angiography?

Despite impressive image quality, it is unclear if noninvasive coronary angiography with multislice spiral computed tomography (CT) is powerful enough to act as a filter before invasive angiography (INV-A) in symptomatic patients. We therefore studied 133 consecutive symptomatic patients with suspected coronary artery disease (CAD) and an indication for INV-A (chest pain and signs of ischemia in conventional stress tests). Patients with known CAD, acute coronary syndrome, or a calcium volume score >1000 were excluded. In all patients, both INV-A and multislice CT angiography (MSCT-A) (Philips MX 8000 multislice spiral CT, scan time 250 milliseconds, slice thickness 1.3 mm, 120 mL of contrast agent, 4 mL/s, retrospective gating) were directly compared by 2 independent investigators using the American Heart Association 15-segment model. Altogether, we studied 1596 segments, 74% had diagnostic image quality. Multislice CT angiography correctly identified 68 significant stenoses of the 75 stenoses seen with INV-A (sensitivity 91%). In 945 of 1185 diagnostic segments, stenosis could correctly be ruled out with MSCT-A. There were 3 times more stenoses seen with MSCT-A compared with INV-A (positive predictive value 29%) mainly because of misclassification of nonobstructive plaques as stenosis. The per-patient analysis allowed to exclude significant CAD in 42 (32%) of 133 patients. In only 6 of 53 patients, MSCT-A failed to detect significant stenosis, 4 of those were in small segments not requiring intervention. Calcium scoring alone was less suited as a filter before angiography: 25 patients (18% of study group) had a calcium score = 0, and 8 of these patients turned out to have significant stenoses. Multislice CT angiography, but not calcium scoring alone, offers promise to reduce the number of INV-A in symptomatic patients with suspected CAD by up to one third with minimal risk for the patient.

MDCT Cholangiography with Volume Rendering for the Assessment of Patients with Biliary Obstruction

We sought to evaluate the diagnostic utility of MDCT cholangiography with volume rendering in the evaluation of patients with suspected biliary tree obstruction. MDCT was performed in 34 patients who were thought to have biliary obstruction. Portal venous phase scanning was initiated 70 sec after the IV infusion of 150 mL of contrast agent, and no cholangiographic contrast agent was administered. Three-dimensional MDCT cholangiographic images were produced using volume rendering. ERCP was performed in 26 patients, and percutaneous transhepatic cholangiography (PTC) was performed in five patients; 17 patients underwent biopsy or surgery. The findings on MDCT cholangiography were compared with those of ERCP, PTC, biopsy, or surgery. The correct diagnosis was made on MDCT cholangiography for 14 (93%) of the 15 patients with a biliary stone and in 16 (94%) of the 17 patients with malignant biliary obstruction. Microlithiasis in one patient could not be detected on MDCT cholangiography. One patient with polypoid adenocarcinoma and one patient with normal findings were incorrectly diagnosed with a biliary stone on the basis of MDCT cholangiography. In one of the two patients with a benign stricture, the stricture was incorrectly diagnosed as malignant. For the diagnosis of biliary stone, sensitivity and specificity of MDCT cholangiography were 93% and 89%, respectively. For the diagnosis of malignant obstruction, sensitivity and specificity were both 94%. The accuracy of the technique for the diagnosis of the cause of biliary obstruction was 83.3%. MDCT cholangiography with volume rendering is a noninvasive and fast imaging technique with high sensitivity and specificity for the diagnosis of the cause of biliary tree obstruction. It is a promising diagnostic tool for the assessment of patients with bile duct obstructions.

Extracorporeal shock wave therapy in the treatment of Peyronie’s disease: experience with standard lithotriptor (siemens-multiline)

Objectives. To assess in a prospective study whether extracorporeal shock wave therapy (ESWT) using a standard radioscopic location lithotriptor is effective in the treatment of Peyronie’s disease. Methods. Fifty-four patients were included in this prospective study. Before and after treatment, the angulation was calculated by auto-photography. Pain severity was assessed by a visual analog pain scale. A self-evaluation questionnaire (International Index of Erectile Function) was used. All patients had symptoms (35 had pain during erection and 51 angulation greater than 20°). The mean disease duration was 16 months. The mean angulation before treatment was 48° (range 10° to 100°). Twenty-four patients had erectile dysfunction (questionnaire score less than 18). The Multiline Siemens lithotriptor was used. The plaque was located by palpation, and 1 mL of contrast agent was injected. Scopic visualization was used. Each patient received a minimum of one session of ESWT (3000 shock waves, 7 kJ) applied to a flaccid penis. Results. All patients completed the protocol. The tolerance and safety were excellent. Of the 35 patients with pain on erection, 31 (91%) noticed relief immediately after ESWT (mean reduction 2.9 on the visual analog pain scale) ( P <0.00001). For 29 patients (53.7%), an improvement in angulation (greater than 10°) was observed, with a mean reduction of 31° ( P <0.001). For patients with erectile dysfunction, only 6 (25%) had an increased questionnaire score (greater than 4). Twenty-five patients thought the plaque was smoother. Conclusions. ESWT with a standard lithotriptor (without the mobile arm) in Peyronie’s disease is a feasible, safe, and effective treatment for pain on erection and significantly improves the penile angle.

Intermittent harmonic imaging and videodensitometry significantly enhance ability of intravenous air-filled ultrasonographic contrast agent to produce ventricular and myocardial opacification

We used visual and videodensitometric evaluation to investigate the influence of intermittent harmonic imaging (IHI) compared with intermittent fundamental imaging on cavity and myocardial signal intensity after administration of the air-filled transpulmonary contrast agent BY963. Twelve patients were studied with intermittent fundamental imaging and IHI after administration of 5 mL and 10 mL of contrast agent. Contrast effect was graded in the parasternal short-axis view. Visually, IHI improved opacification of both the right and left ventricular cavities, especially the left. Densitometrically, right ventricular opacification did not differ significantly between imaging modalities, whereas left ventricular cavity opacification was significantly higher when using IHI. Myocardial opacification was observed in a small minority of segments when assessed by visual estimation, whereas videodensitometry revealed opacification in 42 of 48 anterior, 39 of 48 posterior, and 42 of 48 septal segments. Differences were not significant between doses. We conclude that with IHI and densitometry, air-filled contrast agents like BY963 show significantly improved performance in producing cavity and myocardial contrast effects.

In-plane coronary arterial motion velocity: measurement with electron-beam CT.

To determine the speed of and changes in the speed of coronary arterial movement during the cardiac cycle with electron-beam computed tomography (CT). With electron-beam CT, 20 consecutive cross-sectional images were acquired at the mid right coronary artery (with 50-msec acquisition time, 8-msec intersection delay, 7-mm section thickness, and intravenous administration of 40 mL of contrast agent) in 25 patients. On the basis of the displacement of the left anterior descending, left circumflex, and right coronary arterial cross sections from image to image, movement velocity in the transverse imaging plane was calculated and was correlated with the simultaneously recorded electrocardiogram. The velocity of in-plane coronary arterial motion varied considerably during the cardiac cycle. Peaks were caused by ventricular systole and diastole and by atrial contraction. The mean velocity was 46.6 mm/sec +/- 12. 5 (SD). The mean velocity of right coronary arterial movement (69.5 mm/sec +/- 22.5) was significantly faster than that of the left anterior descending (22.4 mm/sec +/- 4.1) or the left circumflex coronary artery (48.4 mm/sec +/- 15.0). The lowest mean velocity (27. 9 mm/sec) was at 48% of the cardiac cycle. The lowest velocity of coronary arterial movement, which displays considerable temporal variation, was at 48% of the cardiac cycle.

Ligaments of the ankle: normal anatomy with MR arthrography.

Our purpose was to define the normal MR arthrographic anatomy of ankle ligaments. Prior to injection of intraarticular gadolinium in cadaveric ankle joints, proton density and T2-weighted images were obtained to assess the integrity of the ligaments and tendons as well as the amount of preexisting joint effusion. Following injection of 10 ml of contrast agent (gadopentetate dimeglumine 1:250, Omnipaqe 300, Knox gelatin 50%, and methylene blue), T1-weighted images with fat saturation in axial, oblique axial, coronal, and sagittal planes were obtained in neutral, dorsiflexion, and plantar flexion positions. Specimens were sectioned, allowing anatomic and MR correlation. Contrast agent outlining anterior and posterior aspects of the anterior talofibular ligament and posterior talofibular ligament (PTAF) was a normal finding, related to anterior and posterior recesses of the ankle joint that extend out beyond these ligaments in an anteroposterior direction above the level of the ligaments. Intraarticular contrast material allowed resolution of superficial and deep components of the posterior tibiofibular ligament. Both were seen separately from PTAF with dorsiflexion. Posterior intermalleolar ligament was not present in our specimens. Visualization of calcaneofibular ligament was much improved by contrast material outlining the articular aspect of the ligament. Visualization of the syndesmotic ligamentous complex also was improved by contrast material outlining the articular side of the ligaments and separating them from adjacent bone. Superiorly, the distribution of contrast agent was limited by the interosseous ligament. Visualization of the medial collateral ligaments was not improved by the presence of the intraarticular contrast material. MR arthrography of the ankle allows improved visualization and evaluation of the lateral and syndesmotic ligamentous complex.

Double phase CT arteriography of the whole liver in the evaluation of hepatic tumors.

Our goal was to evaluate the contribution of double phase CT arteriography (CTA) of the whole liver to differentiate hepatic tumors from false-positive areas on CT during arterial portography (CTAP). In 38 candidates for surgical resection of hepatic tumors, both CTAP and double phase CTA were performed. A total of 68 perfusion defects were identified at CTAP. Of 68 perfusion defects, 47 were found to represent hepatic tumors [hepatocellular carcinoma (HCC), n = 31; hepatic metastasis, n = 13; cholangiocarcinoma n = 2; focal nodular hyperplasia, n = 1]. The other 21 perfusion defects were defined as perfusion abnormalities in which focal hepatic masses had not been identified at surgery or pathologic analysis. The phase one CTA scanning started 12 s after the beginning of the injection of contrast material, and the phase two CTA scanning started 20 s after the end of the phase one CTA, with 60 ml of contrast agent (150 mg I/ml) injected at a rate of 2 ml/s. On phase one CTA, only 1 lesion in 31 HCCs showed rim enhancement and 26 HCCs (84%) had rim enhancement on phase two CTA. Twelve lesions (80%) of the hepatic metastases and cholangiocarcinomas had rim enhancement on phase one CTA and 11 lesions (73%) showed rim enhancement on phase two CTA. Twenty-one perfusion abnormalities on CTAP did not show rim enhancement on either phase one or phase two CTA. Double phase CT arteriography of the whole liver was useful to differentiate hepatic tumors from perfusion abnormalities on CTAP.

Cystic tumors of the pancreas: dynamic CT studies.

Our retrospective study was performed to reassess the common dynamic CT manifestations of cystic tumors of the pancreas and to determine whether they might allow the differentiation between benign and malignant tumors. Dynamic CT examinations of 19 patients with 20 cystic tumors of the pancreas, including 7 serous cystadenomas, 3 benign mucinous cystadenomas, 5 mucinous cystadenocarcinomas, 3 mucin-producing duct ectasias, and 2 papillary cystic epithelial neoplasms, were retrospectively reviewed. The examinations were obtained with 4 to 5 mm collimation with intravenous injection of 120-130 ml of contrast agent. Calcifications were found only in benign tumors (seven serous cyst-adenomas). Internal septations were found in benign and malignant tumors (seven serous cystadenomas, three benign mucinous cystadenomas, three mucinous cystadenocarcinomas). Solid excrescences within cystic cavities were found only in malignant tumors (two mucinous cystadenocarcinomas, two mucin-producing duct ectasias). Dynamic CT features allowed the distinguishing of serous cystadenomas from other cystic tumors and mucin-producing duct ectasias from other mucinous tumors. Dynamic CT features did not permit differentiation between benign mucinous cystadenomas, mucinous cystadenocarcinomas, and papillary cystic epithelial neoplasms. The review suggests that dynamic CT findings are useful to differentiate (a) serous cystadenomas and mucin-producing duct ectasias from other cystic tumors of the pancreas and (b) benign from malignant tumors. Such differentiation has impact on patient management.