Prostate postbrachytherapy seed distribution: comparison of high-resolution, contrast-enhanced, T1- and T2-weighted endorectal magnetic resonance imaging versus computed tomography: initial experience.

PURPOSE: To compare contrast-enhanced, T1-weighted, three-dimensional magnetic resonance imaging (CEMR) and T2-weighted magnetic resonance imaging (T2MR) with computed tomography (CT) for prostate brachytherapy seed location for dosimetric calculations. METHODS AND MATERIALS: Postbrachytherapy prostate MRI was performed on a 1.5 Tesla unit with combined surface and endorectal coils in 13 patients. Both CEMR and T2MR used a section thickness of 3 mm. Spiral CT used a section thickness of 5 mm with a pitch factor of 1.5. All images were obtained in the transverse plane. Two readers using CT and MR imaging assessed brachytherapy seed distribution independently. The dependency of data read by both readers for a specific subject was assessed with a linear mixed effects model. RESULTS: The mean percentage (+/- standard deviation) values of the readers for seed detection and location are presented. Of 1205 implanted seeds, CEMR, T2MR, and CT detected 91.5% +/- 4.8%, 78.5% +/- 8.5%, and 96.1% +/- 2.3%, respectively, with 11.8% +/- 4.5%, 8.5% +/- 3.5%, 1.9% +/- 1.0% extracapsular, respectively. Assignment to periprostatic structures was not possible with CT. Periprostatic seed assignments for CEMR and T2MR, respectively, were as follows: neurovascular bundle, 3.5% +/- 1.6% and 2.1% +/- 0.9%; seminal vesicles, 0.9% +/- 1.8% and 0.3% +/- 0.7%; periurethral, 7.1% +/- 3.3% and 5.8% +/- 2.9%; penile bulb, 0.6% +/- 0.8% and 0.3% +/- 0.6%; Denonvillier's Fascia/rectal wall, 0.5% +/- 0.6% and 0%; and urinary bladder, 0.1% +/- 0.3% and 0%. Data dependency analysis showed statistical significance for the type of imaging but not for reader identification. CONCLUSION: Both enumeration and localization of implanted seeds are readily accomplished with CEMR. Calculations with MRI dosimetry do not require CT data. Dose determinations to specific extracapsular sites can be obtained with MRI but not with CT.

Contrast-enhanced high-resolution magnetic resonance imaging of autologous cartilage implants of the knee joint.

Over the past decade, a number of interventions for durable cartilage repair have emerged. Magnetic resonance (MR) tomography is an excellent noninvasive method for monitoring cartilage repair tissues throughout the postsurgical period. However, evaluating cartilage morphology after matrix-based autologous cartilage implantation (ACI) with MR imaging (MRI) still remains a challenge. In this study, we combined a high-resolution cartilage-sensitive fast-spin echo (FSE) sequence with intravenous application of a contrast agent for enhancing synovial fluid. Two independent musculoskeletal radiologists interpreted the pictures for the thickness, length and surface of the cartilage implants. A multivariate two-way analysis of variance with two repeated measures was performed and showed that evaluation of cartilage implant morphology was significantly improved after the application of gadodiamide on proton density FSE images. Contrast-enhanced MRI of articular cartilages is a promising technique in the postoperative follow-up of patients after ACI.

Intrapulmonary shunt after cardiopulmonary bypass: the use of vital capacity maneuvers versus off-pump coronary artery bypass grafting.

OBJECTIVES: It has been proved in human subjects and animals that atelectasis is a major cause of intrapulmonary shunting and hypoxemia after cardiopulmonary bypass. Animal studies suggest that shunting can be prevented entirely by a total vital capacity maneuver performed before termination of bypass. This study aimed to test this theory in human subjects and to evaluate possible advantages of off-pump coronary artery bypass grafting. METHODS: Twenty-four patients scheduled for coronary artery bypass grafting were randomly assigned to receive no total vital capacity maneuver (control group, n = 12) or standard total vital capacity maneuvers (TVCM group, n = 12). Additionally, 12 consecutive patients undergoing off-pump coronary artery bypass grafting (off-pump group) were studied. Systemic and central hemodynamics, the pattern of breathing, and ventilatory mechanics were evaluated after induction of anesthesia, after sternotomy, after cardiopulmonary bypass and skin closure, and 4 hours after extubation. RESULTS: The use of total vital capacity maneuvers reduced (P <.05) intrapulmonary shunting after termination of cardiopulmonary bypass. However, shunting increased (P <.05) in all groups (control group, 8.2% +/- 3.3% vs 25.6% +/- 8.1%; TVCM group, 8.7% +/- 3.4% vs 24.4% +/- 8.5%; and off-pump group, 7.8% +/- 2.8% vs 14.0% +/- 5.3%) after extubation, but the increase was significantly (P <.05) less pronounced in the off-pump group. Furthermore, pulmonary compliance decreased (P <.05) in all groups except the off-pump group after extubation. Duration of hospital and intensive care unit stay was significantly shorter (P <.05) in the off-pump group than in the other groups. CONCLUSION: The development of intrapulmonary shunting and hypoxemia after coronary artery bypass grafting can be substantially reduced by performance of total vital capacity maneuvers while patients are mechanically ventilated. However, off-pump coronary artery bypass surgery is superior in preventing shunting and hypoxemia after bypass grafting in the immediate and early postoperative periods, probably leading to substantially shorter intensive care unit and hospital stays.

Three-dimensional volume rendering of multidetector-row CT data: applicable for emergency radiology.

Multidetector-row computed tomography (MD-CT) not only creates new opportunities but also challenges for medical imaging. Isotropic imaging allows in-depth views into anatomy and disease but the concomitant dramatic increase of image data requires new approaches to visualize, analyze and store CT data. The common diagnostic reviewing process slice by slice becomes more and more time consuming as the number of slice increases, while on the other hand CT volume data sets could be used for three-dimensional visualization. These techniques allow for comprehensive interpretation of extent of fracture, amount of dislocation and fragmentation in a three-dimensional highly detailed setting. Further more, using minimal invasive techniques like CT angiography, new opportunities for fast emergency room patient's work up arise. But the most common application is still trauma of the musculoskeletal system as well as face and head. The following is a brief review of recent literature on volume rendering technique and some exemplary applications for the emergency room.

Atypical idiopathic inflammatory demyelinating lesions (IIDL): conventional and diffusion-weighted MR imaging (DWI) findings in 42 cases.

INTRODUCTION: The purpose of this study was to evaluate MR imaging characteristics with conventional and advanced MR imaging techniques in patients with IIDL. METHODS: MR images of the brain in 42 patients (20 male, 22 female) with suspected or known multiple sclerosis (MS) from four institutions were retrospectively analyzed. Lesions were classified into five different subtypes: (1) ring-like lesions; (2) Balo-like lesions; (3) diffuse infiltrating lesions; (4) megacystic lesions; and (5) unclassified lesions. The location, size, margins, and signal intensities on T1WI, T2WI, and diffusion-weighted images (DWI), and the ADC values/ratios for all lesions, as well as the contrast enhancement pattern, and the presence of edema, were recorded. RESULTS: There were 30 ring-like, 10 Balo-like, 3 megacystic-like and 16 diffuse infiltrating-like lesions were detected. Three lesions were categorized as unclassified lesions. Of the 30 ring-like lesions, 23 were hypointense centrally with a hyperintense rim. The mean ADC, measured centrally, was 1.50 ± 0.41 × 10(-3) mm(2)/s. The mean ADC in the non-enhancing layers of the Balo-like lesions was 2.29 ± 0.17 × 10(-3) mm(2)/s, and the mean ADC in enhancing layers was 1.03 ± 0.30 × 10(-3) mm(2)/s. Megacystic lesions had a mean ADC of 2.14 ± 0.26 × 10(-3)mm(2)/s. Peripheral strong enhancement with high signal on DWI was present in all diffuse infiltrating lesions. Unclassified lesions showed a mean ADC of 1.43 ± 0.13 mm(2)/s. CONCLUSION: Restriction of diffusion will be seen in the outer layers of active inflammation/demyelination in Balo-like lesions, in the enhancing part of ring-like lesions, and at the periphery of infiltrative-type lesions.

Endovascular therapy of ruptured abdominal aortic aneurysm: mid- and long-term results.

As an alternative to open aneurysm repair, emergency endovascular aortic repair (EVAR) has emerged as a promising technique for ruptured abdominal aortic aneurysm (rAAA) within the last decade. The aim of this retrospective study is to present early and late outcomes of patients treated with EVAR for rAAA. Twenty-two patients (5 women, 17 men; mean age, 74 years) underwent EVAR for rAAA between November 2000 and April 2006. Diagnostic multislice computed tomography angiography was performed prior to stent-graft repair to evaluate anatomical characteristics and for follow-up examinations. Periprocedural patient characteristics and technical settings were evaluated. Mortality rates, hospital stay, and early and late complications, within a mean follow-up time of 744 +/- 480 days, were also assessed. Eight of 22 patients were hemodynamically unstable at admission. Stent-graft insertion was successful in all patients. The total early complication rate was 54%, resulting in a 30-day mortality rate of 23%. The median intensive care unit stay was 2 days (range, 2-48 days), and the median hospital stay was 16 days (range, 9-210 days). During the follow-up period, three patients suffered from stent-graft-related complications. The overall mortality rate in our study group was 36%. EVAR is an acceptable, minimally invasive treatment option in patients with acute rAAA, independent of the patient's general condition. Short- and long-term outcomes are definitely comparable to those with open surgical repair procedures.

Uroflow nomogram for male adolescents.

PURPOSE: Uroflowmetry is well established for investigating lower urinary tract symptoms. Current nomograms are based on sample sizes limited to 8 men of the same age. We generated percentile curves for the maximum urinary flow rate (Qmax) in relation to voided volume in male adolescents in a large homogenous healthy group. MATERIALS AND METHODS: A total of 348 males who were 18 years old were investigated, excluding probands with a urological history. Only samples with a voided volume of 150 cc or more were included. One micturition was obtained per proband to determine Qmax, the average urinary flow rate, time to Qmax and volume. Resulting curves were compared with nomograms for children and adults. RESULTS: Average voided volume +/- SD was 262 +/- 91.9 cc (range 151 to 664). Qmax was 28.4 +/- 9.7 cc per second (range 11.4 to 76) with an average urinary flow rate of 18.6 +/- 5.5 cc per second (range 4 to 44), a micturition time of 16.9 +/- 6.8 seconds (range 7 to 48) and a mean time to Qmax of 7.8 +/- 4.1 seconds (range 1 to 25). A total of 341 probands had a Qmax of more than 15 cc per second, while only 7 showed a Qmax of less than 15 cc per second. At up to 350 cc Qmax increased with volume, followed by a plateau phase at 350 to 550 cc and a Qmax decrease at higher volumes. CONCLUSIONS: Voiding volumes in a large homogenous adolescent group demonstrated optimal Qmax at voiding volumes between 350 and 550 cc with a decrease at higher volumes. Therefore, uroflow studies in adolescent males should be interpreted with caution at volumes less than 350 and more than 550 cc.