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Purpose: Treatment algorithms for brainstem cavernous malformations (BSCM) are still discussed controversially. The aim of our study is to provide the results of a centre with a long-standing experience in the micro-surgical resection and the radiosurgical treatment of BSCM and to elucidate how to best use the two different treatment options for the benefit of the patient. Patients an. Methods: 29 patients (female: male = 13: 16) were treated microsurgically. In 38 patients (female: male = 19:19) Gamma Knife radiosurgery (GKRS) was applied. Surgical approaches have been chosen according to the most direct approach with the lowest risk of neurological deficits. GKRS patients were treated with a Leksell Gamma Knife. Gamma Knife parameters were applied as following: median margin dose 12 Gy (6 -16 Gy), median maximum dose 24 Gy (8 - 32 Gy), median isodose line 50% (45 - 80%). Clinical data were obtained by retrospective chart review. A minimum follow up of 2 years was established and a recent follow up was evaluated for all patients resulting in a median follow up of 7.7 years (2.0 - 22.1 years). Patients were rated according to the modified Rankin scale (mRS). Results: Statistical significant differences revealed that radiosurgically treated patients harboured significantly smaller and deep seated lesions (p<0.001). Surgically treated patients more often showed intralesional or extralesional haemorrhage (p=0.002), were superficially seated but larger and presented with a significantly higher preoperative mRS score (p=0.019). In both treatment groups, patients presented with a significant better mRS score (p=0.002, p<0.001) at time of follow up compared to the mRS score prior to surgery or GKRS. Overall annual pre-operative haemorrhage rates were calculated as 3.2% among surgery patients and 2.3% among GKRS patients. The annual pre-operative re-hemorrhage rate amounted to 25.1% for surgery and 7.2% for GKRS patients in the observation period. The overall annual post-operative haemorrhage rate for GKRS patients was 1.3% at time of follow up. In the first two years after GKRS the haemorrhage rate was 2.6% but dropped to 0.6% after the first two years. The annual postoperative haemorrhage rate was 8.8% for surgically treated patients with residual lesions. Conclusion: GKRS and microsurgery are complimentary treatment options that both result in a favourable patient outcome if applied on accurately selected patients in a multidisciplinary setting. Disclosure: No significant relationships. [ABSTRACT FROM AUTHOR]

Background: The superior thalamic vein (STV) was first described comprehensively by Ferner in 1958 as the most prominent thalamic vein; it originates from the central superior portion of the thalamus, coursing medially to the third ventricular thalamic surface, where it turns posteriorly to parallel the internal cerebral vein (ICV) before ending into its posterior portion. Since historical anatomic and angiographic studies in the pre-computed tomography (CT)/magnetic resonance imaging era, the STV has not been investigated., Objective: To describe the anatomic course of the STV with its variations, and to propose a classification system based on its draining pattern., Methods: We retrospectively screened our imaging database for 50 patients who had a CT-angiography with predefined parameters. The images were independently reviewed by 3 neurosurgeons and 1 neuroradiologist to classify the STV into 4 types: type 1A-drainage into the anterior portion of the ICV, type 1B-drainage into the posterior portion of the ICV, type 2-drainage into the vein of Rosenthal, type 3-drainage into a medial (3A) or lateral (3B) atrial vein, and type 4-drainage into the vein of Galen., Results: In 50 patients, we could identify 96 STVs. In 2 hemispheres, the STV was doubled. The 92 single STVs were classified as type 1A in 25 hemispheres (27.2%), type 1B in 45 (48.9%), type 2 in 12 (13.0%), type 3A in 8 (8.7%), type 3B in 1 (1.1%), and type 4 in 1 (1.1%)., Conclusion: The draining pattern of the STV varies widely from the initial description.

Objective: The authors present long-term follow-up data on patients treated with Gamma Knife radiosurgery (GKRS) for acoustic neuroma., Methods: Six hundred eighteen patients were radiosurgically treated for acoustic neuroma between 1992 and 2016 at the Department of Neurosurgery, Medical University Vienna. Patients with neurofibromatosis and patients treated too recently to attain 1 year of follow-up were excluded from this retrospective study. Thus, data on 557 patients with spontaneous acoustic neuroma of any Koos grade are presented, as are long-term follow-up data on 426 patients with a minimum follow-up of 2 years. Patients were assessed according to the Gardner-Robertson (GR) hearing scale and the House-Brackmann facial nerve function scale, both prior to GKRS and at the times of follow-up., Results: Four hundred fifty-two patients (81%) were treated with radiosurgery alone and 105 patients (19%) with combined microsurgery-radiosurgery. While the combined treatment was especially favored before 2002, the percentage of cases treated with radiosurgery alone has significantly increased since then. The overall complication rate after GKRS was low and has declined significantly in the last decade. The risk of developing hydrocephalus after GKRS increased with tumor size. One case (0.2%) of malignant transformation after GKRS was diagnosed. Radiological tumor control rates of 92%, 91%, and 91% at 5, 10, and 15 years after GKRS, regardless of the Koos grade or pretreatment, were observed. The overall tumor control rate without the need for additional treatment was even higher at 98%. At the last follow-up, functional hearing was preserved in 55% of patients who had been classified with GR hearing class I or II prior to GKRS. Hearing preservation rates of 53%, 34%, and 34% at 5, 10, and 15 years after GKRS were observed. The multivariate regression model revealed that the GR hearing class prior to GKRS and the median dose to the cochlea were independent predictors of the GR class at follow-up., Conclusions: In small to medium-sized spontaneous acoustic neuromas, radiosurgery should be recognized as the primary treatment at an early stage. Although minimizing the cochlear dose seems beneficial for hearing preservation, the authors, like others before, do not recommend undertreating intracanalicular tumors in favor of low cochlear doses. For larger acoustic neuromas, radiosurgery remains a reliable management option with tumor control rates similar to those for smaller acoustic neuromas; however, careful patient selection and counseling are recommended given the higher risk of side effects. Microsurgery must be considered in acoustic neuromas with significant brainstem compression or hydrocephalus.

Clinical/methodical Issue: Acceleration-deceleration rotational brain trauma is a common cause of disability or death in young adults and often leads to a focal destruction of axons. The resulting pathology, axonal shear injury is referred to as diffuse axonal injury (DAI). The DAI-associated lesions occur bilaterally, are widely dispersed and have been observed in the surface and deep white matter. They are found near to and far from the impact site., Standard Radiological Methods: When DAI is clinically suspected, magnetic resonance imaging (MRI) is the method of choice for further clarification, especially in patients where cranial computed tomography (CT) is inconspicuous., Methodical Innovations: To investigate the presence of DAI after traumatic brain injury (TBI), a multimodal MRI approach is applied including the common structural and also functional imaging sequences., Performance: For structural MRI, fluid-attenuated inversion recovery (FLAIR) weighted and susceptibility contrast imaging (SWI) are the sequences mainly used. The SWI technique is extremely sensitive to blood breakdown products, which appear as small signal voids at three locations, at the gray-white interface, in the corpus callosum and in the brain stem. Functional MRI comprises a group of constantly developing techniques that have great potential in optimal evaluation of the white matter in patients after craniocerebral trauma. These imaging techniques allow the visualization of changes associated with shear injuries, such as functional impairment of axons and decreased blood flow and abnormal metabolic activity of the brain parts affected., Achievements: The multimodal MRI approach in patients with DAI results in a more detailed and differentiated representation of the underlying pathophysiological changes of the injured nerve tracts and helps to improve the diagnostic and prognostic accuracy of MRI., Practical Recommendations: When DAI is suspected multimodal MRI should be performed as soon as possible after craniocerebral injury.

Background: Recent studies have demonstrated a high sensitivity (S) of 16-multidetector computed tomography (16-MDCT) for the detection of significant coronary artery stenoses. Whether these results are applicable to clinical practice is unclear. Therefore, the aim of the present study was to compare 16-MDCT angiography with conventional coronary angiography (CCA) for the detection of significant coronary artery stenoses in a consecutive series of patients., Method: A total of 93 consecutive patients (mean [+/- SD] age 59+/-9 years), in whom CCA was performed for stable angina pectoris, underwent 16-MDCT angiography (16x0.75 mm, table feed 6.5 mm/s, rotation time 0.42 s; Sensation 16, Siemens Medical Solutions, Germany) the day before performing CCA. Patients with diabetes mellitus, serum creatinine level higher than 132.6 mumol/L and/or acute coronary syndromes were excluded. Two observers blinded to CCA results evaluated MDCT angiograms according to standard criteria. Segment-based (13 segments per patient) and patient-based (at least one stenosis greater than 50% lumen diameter reduction) analyses were performed., Results: A total of 1209 segments were analyzed. Of these segments, 173 (14%) were excluded due to poor image quality or massive calcification. In 86 segments, CCA revealed significant coronary artery stenosis (greater than 50% diameter reduction). However, 16-MDCT detected only 47 of these, resulting in a S of 55% and a specificity (SP) of 97% (positive predictive value 64%; negative predictive value 96%). On a patient-based analysis, the S increased to 89%, whereas the SP still remained high (87%)., Conclusion: In this relatively large consecutive cohort, S for the detection of significant coronary artery stenoses was moderate on a segment-based analysis but increased on a patient-based analysis using 16-MDCT. In contrast, SP was high in both analyses, supporting the use of 16-MDCT for the exclusion of significant coronary artery stenoses. Further improvement of spatial and temporal resolution in MDCT technology may lead to a lower exclusion rate and higher S.

Most traumatic spinal injuries result from a high-energy process and are accompanied by other injuries. Following the CCSPR study, the presence of all low-risk factors (simple trauma mechanism, fully conscious, ambulatory at any time since trauma, neck rotation exceeding 45 degrees bilaterally) obviates the need to acutely image the cervical spine. Imaging is indicated in all other patients. Emergency spiral CT should be performed as the first imaging method in high-risk and moderate-risk patients; only in low-risk patients should conventional radiography be performed and trusted as the sole modality. The AO classification according to Magerl et al. is used for the subaxial spine, whereas the upper cervical spine should be classified separately because the anatomy is different at each level. Radiological evaluation of traumatic spinal injuries should be done systematically using the "ABCS" scheme.

Objective: This study evaluates whether ECG-gated 16-MDCT coronary angiography provides a reliable imaging technique for detecting aortic regurgitation (AR)., Subjects and Methods: We examined 71 patients prospectively with 16-MDCT angiography using retrospective ECG gating during the mid-to-end diastolic phase. A visible central valvular leakage area was considered as a diagnostic criterion for AR. The central valvular leakage area was quantified in patients with positive transthoracic echocardiography (TTE). We compared 16-MDCT to Doppler TTE, the accepted diagnostic standard based on semiquantitative regurgitation jet analysis (grade 0-3+ for mild, moderate, and severe)., Results: The overall sensitivity of 16-MDCT for the identification of patients with AR was 81%. The specificity was 91%, the negative predictive value was 70%, and the positive predictive value was 95%. Of the 71 patients, 48 had AR determined by TTE, and 16-MDCT correctly detected AR in 39 of those 48 patients. The sensitivity of 16-MDCT for the detection of patients with moderate and severe AR (grade > or = 1.5+) was 95%, and the specificity was 96% (20 of 21 patients). The sensitivity of 16-MDCT for identification of patients with mild AR (grade < or = 1+) was 70%, and the specificity was 92% (19 of 27 patients). Quantification of the central valvular leakage area was not possible in 50% of cases with AR by TTE because of valve calcifications., Conclusion: Sixteen-MDCT coronary angiography provides an accurate, noninvasive imaging technique to detect moderate and severe aortic regurgitation (grade > or = 1.5+). However, severe valve calcifications and mild AR limit its results.

Objective: The purpose of this study was to retrospectively assess the accuracy of gray-scale and color Doppler sonography in the diagnosis of carpal tunnel syndrome., Materials and Methods: A total of 206 wrists in 151 patients with a clinical suspicion of carpal tunnel syndrome were examined with high-resolution sonography using a 7-15-MHz linear array transducer. The presence of median nerve swelling, edema, and flattening and increased bowing of the flexor retinaculum was evaluated with gray-scale sonography, and the presence of nerve hypervascularization was evaluated with color Doppler sonography. Sensitivity and specificity were calculated for each sonographic feature in comparison with nerve conduction studies as the standard of reference. Multivariate logistic regression analysis was used to determine variables predictive of carpal tunnel syndrome., Results: Carpal tunnel syndrome was confirmed in 172 wrists at nerve conduction studies. A median nerve cross-sectional area of at least 0.11 cm2 was calculated as a definition of median nerve swelling. In comparison with nerve conduction studies, nerve swelling showed the highest accuracy (91%) among gray-scale sonography criteria, and the presence of intraneural hypervascularization showed the highest accuracy (95%) among all sonography criteria. Logistic regression analysis showed that nerve hypervascularization was the only variable that independently predicted median nerve entrapment (odds ratio, 16.4; 95% confidence interval, 8.7-31.1; p <0.001)., Conclusion: Color Doppler sonography is more accurate than gray-scale sonography for characterizing median nerve involvement in patients with suspected carpal tunnel syndrome.

Objectives: The purpose of this study was to evaluate whether multislice computed tomography (MSCT) provides a reliable, noninvasive imaging modality for identification of patients with degenerative aortic valve stenosis (AS) by quantifying the aortic valve area (AVA) in comparison to the accepted diagnostic standard transthoracic echocardiography (TTE)., Background: Management of patients with degenerative AS is based on the severity of disease. The severity of AS in clinical practice is assessed by TTE and classified as mild, moderate, or severe according to the AVA., Methods: Forty-six patients were examined with contrast-enhanced, electrocardiogram-gated, 16-row MSCT for the evaluation of the diagnostic accuracy. In 30 patients, quantification of the AVA with MSCT was compared to TTE using the continuity equation with Doppler velocity-time integral for calculation of the AVA., Results: Sensitivity of MSCT for the identification of patients with degenerative AS was 100%, and the specificity was 93.7%. Thirty of 46 patients had AS determined by TTE. Quantification of AVA by MSCT (mean AVA = 0.94 cm2) in patients with AS showed a good correlation to TTE (r = 0.89; p < 0.001). Bland-Altman plot illustrated good intermodality agreement between the two methods (limits of agreement, 0.20; 0.29)., Conclusions: Multislice computed tomography may provide an accurate, noninvasive imaging technique for detection of patients with AS and quantification of AVA.

Objective: The purpose of this study was to retrospectively assess the accuracy of MDCT angiography as the initial diagnostic technique to depict arterial injury in patients with extremity trauma., Materials and Methods: Over 36 months, 87 patients (16 females and 71 males; age range, 16-87 years) with clinically suspected arterial injury after extremity trauma underwent 4-MDCT angiography and 67 ultimately underwent surgery. Eighty patients had blunt injuries, and seven had penetrating injuries. The presence of arterial involvement was investigated prospectively by the radiologist in charge and retrospectively by two independent radiologists. Each detected arterial lesion was then characterized as a spasm, stenosis, occlusion, or rupture. The standard of reference was surgery in 67 patients, angiography in two patients, and clinical and radiologic follow-up findings in 18 patients. MDCT angiography was assessed by means of receiver operating characteristic (ROC) curve analysis for lesion detection and Spearman's rank correlation test for lesion characterization. Image quality, lesion depiction, and artifacts were subjectively assessed., Results: Sixty-two traumatic arterial lesions were confirmed at surgery in 55 patients. MDCT angiography yielded high accuracy in detection (area under the ROC curve [Az] = 0.96; p < 0.001) and characterization (r = 0.94; p < 0.001) of traumatic arterial injuries and in recognizing an underlying dissection (Az= 0.82; p < 0.001). Prospective sensitivity and specificity were 95% and 87%, respectively, and retrospective sensitivity and specificity were 99% and 87%, respectively. MDCT angiography was considered to be sufficient for a reliable diagnosis in 83 patients (p < 0.001). Image quality and lesion depiction on MDCT angiograms were considered to be good and artifacts were considered mild with substantial interobserver agreement (kappa, 0.62-0.69)., Conclusion: MDCT angiography provides significant and reproducible technique for the detection and characterization of arterial injuries to the extremities with high image quality and vascular delineation.

Retrograde blood flow can occur in the testicular veins and in the pampiniformis plexus in the absence of valves or if the valves are incompetent, resulting in tortuosity and dilatation of the veins. These abnormal alterations in the anatomy of the veins, termed varicoceles, are associated with infertility in the male. Most varicoceles occur on the left. We report the case of a rare isolated right-sided varicocele in a male evaluated for infertility in whom extensive work-up revealed venous anomalies and a spontaneous porto-systemic shunt. In such cases, standard approaches to infertility treatment are fruitless.

Our objective was to evaluate the usefulness of CT virtual preoperative planning in the surgical repositioning of malunited distal radius fracture. Eleven patients with malunited distal radius fracture underwent multislice CT of both wrists. A preoperative workup was performed in a virtual reality environment created from the CT data sets. Virtual planning comprised three main procedures, carrying out the virtual osteotomy of the radius, prediction of the final position of the distal radius after osteotomy and computer-assisted manufacturing of a repositioning device, which was later placed at the surgical osteotomy site to reposition objectively the distal radius fragment before fixation with the osteosynthesis. All patients tolerated the surgical procedure well. During surgery, the orthopedic surgeons were not required in any of the cases to alter the position of the distal radius that was determined by the repositioning device. At postoperative follow-up, the anatomic relationship of the distal radius was restored (radial inclination, 21.4 degrees ; volar tilt, 10.3 degrees ; ulnar variance, 0.5 mm). Clinically, a significant improvement of pronation (P=0.012), supination (P=0.01), flexion (P=0.001) and extension (P=0.006) was achieved. Pain decreased from 54 to 7 points. CT virtual reality is a valuable adjunct for the preoperative workup and surgical reposition of malunited distal radius fractures.

Aim: Magnetic resonance imaging, computed tomography, endorectal and endoanal sonography are used for imaging of inflammatory and neoplastic conditions of the lower rectum, the anus and the perineum. These methods, however, have their limitations regarding accuracy, cost-effectiveness, and availability in the acute setting. Pain may be a limiting factor when introducing a probe into the anus. Percutaneous transperineal sonography is an acknowledged method for diagnosing anorectal malformations in children and infants and for diagnosis of prostatic disease. Until today, only limited reports regarding the value of transperineal sonography for evaluation of diseases of the lower rectum, the anus and the perianal region in adults are available., Patients and Methods: Between 1997 and 2000 a total of 44 patients underwent transperineal sonography including B-mode and colour Doppler sonography for imaging anorectal structures using 3.5 MHz sector arrays and 7 MHz linear arrays. The lesions were also investigated using colour Doppler imaging. During examination the patient is positioned on his side. Orientation landmarks are the pubic symphysis and the prostate gland in men and the vagina in women., Results: The spectrum of diseases of the current study population (44) included perianal fistulas (10), pararectal abscesses (7), fistulas with abscess (7), perianal inflammation without abscess (1), rectal (6) and anal carcinomas (3) and metastasis of a leiomyosarcoma (1). In 10 cases digital examination of the anus and rectum was not possible because of intense pain. In 34 patients (85 %) sonographic findings were confirmed by intraoperative diagnosis., Conclusion: Transperineal sonography proved to be an inexpensive, easily available diagnostic tool that may help in detecting a variety of pathological conditions of the lower rectum, the anus, and the perianal region.

Purpose: To evaluate the outcome of stent-graft placement in Stanford type B aortic dissection using contrast-enhanced spiral computed tomographic (CT) measurements of true and false lumen volumes and thrombus length., Methods: Among 18 consecutive patients (13 men; mean age 60 years, range 44-79) who underwent endovascular repair of Stanford type B dissection, 12 completed at least a 12-month follow-up, which included CT measurements of true and false lumen volumes and thrombus lengths prior to discharge and at 6 and 12 months postimplantation. Volumes were assessed in 3 different aortic segments (A1, A2, A3) extending from the proximal attachment site of the prosthesis to the aortic bifurcation. In addition, thrombus length was measured to evaluate the influence of clot formation on outcome of the false lumen volume., Results: Mean follow-up was 27 months (range 12-60). Within 12 months, mean true lumen volumes showed statistically significant increases in the A1 (p<0.001) and A2 (p=0.003) segments; false lumen volumes showed a significant decrease in the A1 segment (p=0.002) but an insignificant increase in the A2 segment. No substantial volume changes were observed in the A3 segment. Extension of clot formation in the false lumen varied among patients and over time. Length of stent-grafts, percentage of stented dissection length, or visceral arteries originating from the false lumen did not significantly influence thrombus development, nor did these parameters or thrombus formation distal to the prosthesis have a relationship to false lumen volumes., Conclusions: Volumetric analysis after endovascular repair of Stanford type B dissection shows optimal technical outcome in the stented segment, whereas the false lumen in the segment immediately adjacent to the stent-graft seems to be a vulnerable area. Extension of clot formation beyond the endograft seems to be no reliable predictor of outcome.

Purpose: To report successful endovascular stent-graft placement for emergency treatment of a complex traumatic injury involving the aortic arch and multiple arch vessels., Case Report: An 81-year-old man underwent stent-graft placement for a complex traumatic vascular injury. Computed tomography on admission documented a dissection along the course of the aortic arch, intramural hematoma along the ascending aorta, dissection of the innominate artery, and a right subclavian artery pseudoaneurysm. The dissection of the aortic arch and the pseudoaneurysm of the right subclavian artery were treated immediately, the dissection of the innominate artery 7 days later. The patient did not develop any complications. Follow-up studies performed prior to discharge and at 6 and 12 months after the interventions showed successful repair of the complex vascular injuries., Conclusions: Traumatic injury of the aortic arch with multiple arch vessel involvement can be treated effectively by means of stent-graft placement.

Objective: The aim of this study was to determine the accuracy of CT arterioportography and hepatic digital subtraction angiography, separately and combined, for the detection of hepatocellular carcinoma in the cirrhotic liver by using thin-section liver explant histopathologic findings., Subjects and Methods: Fifty-nine patients with liver cirrhosis were examined with CT arterioportography and digital subtraction angiography as a part of preoperative diagnostic workup for liver transplantation. Before liver explantation, CT arterioportograms and digital subtraction angiograms were prospectively evaluated in a blinded manner, separately by two CT radiologists and two angiographers, respectively, and combined by two reviewer teams, each including a CT radiologist and an angiographer. In addition, each examination was retrospectively evaluated using direct comparison with the corresponding thin-section liver explant specimens, Results: There were 39 histologically confirmed hepatocellular carcinomas. In both prospective and retrospective assessments, the reviewers achieved the best performance with CT arterioportography and digital subtraction angiography combined (area under the curve [A(z)] 0.82). The diagnostic confidence in the detection of hepatocellular carcinoma was higher with digital subtraction angiography (A(z), 0.81) than that with CT arterioportography (A(z), 0.68). Prospectively, sensitivity and specificity were 75% and 60% for CT arterioportography, 77% and 80% for digital subtraction angiography, and 84% and 81% for CT arterioportography and digital subtraction angiography combined, respectively. Retrospectively, sensitivity and specificity were 80% and 62% for CT arterioportography; 82% and 79% for digital subtraction angiography; 87% and 81% for CT arterioportography and digital subtraction angiography combined, respectively. Five hepatocellular carcinomas, one poorly and four well differentiated, with a mean size of 1.4 cm were not detectable on the CT arterioportography and digital subtraction angiography combination. False-positive findings were 20, 11, and 10 on CT arterioportography, digital subtraction angiography, and the CT arterioportography and digital subtraction angiography combination., Conclusion: Combining CT arterioportography with digital subtraction angiography enabled reliable detectability of moderately and poorly differentiated hepatocellular carcinomas in cirrhotic livers but was less sensitive for the detection of well-differentiated hepatocellular carcinomas and resulted in a relatively high rate of false-positive findings.

Objective: The purpose of this study was to compare volume rendering and maximum intensity projection as postprocessing techniques of MR angiography in the detection and characterization of intracranial aneurysms., Materials and Methods: Three-dimensional time-of-flight MR angiography studies performed in 82 patients were retrospectively evaluated by two independent reviewers who were unaware of digital subtraction angiography findings, the standard of reference. Panoramic maximum-intensity-projection and volume-rendered angiograms were produced from each data set to investigate the presence of underlying aneurysms. Each detected aneurysm was then interactively evaluated with subvolume maximum-intensity-projection and targeted volume-rendering algorithms to evaluate aneurysm morphology and size. Aneurysm detection and characterization were evaluated by means of the receiver operating characteristic analysis, and aneurysm size was evaluated using the limits-of-agreement method. Image quality, aneurysm neck depiction, and vascular delineation were also compared between maximum-intensity-projection and volume-rendered images. The time required for the generation and interpretation of maximum-intensity-projection and volume-rendered images was assessed., Results: Volume rendering tended to improve the diagnostic confidence (A(z) [area under the receiver operating characteristic curve] = 0.95 vs A(z) = 0.90 for maximum intensity projection) and yielded a considerable improvement in sensitivity (89% vs 71% for maximum intensity projection), particularly in the detection of small cerebral aneurysms. Regarding aneurysm morphology, volume rendering performed significantly better than maximum intensity projection in lobulation detection (p < 0.001) and slightly better in neck categorization (p > 0.238). Limits-of-agreement analysis showed a trend toward improved assessment of the aneurysm size by volume rendering (-0.31 +/- 1.62 mm vs -1.27 +/- 2.84 mm by maximum intensity projection). Overall image quality and vascular delineation of involved vessels on volume-rendered images were rated better than that obtained by maximum intensity projections (p < or = 0.007 and p < or = 0.001, respectively). Evaluation of time-of-flight MR angiography data sets was significantly facilitated with volume rendering (p < 0.001)., Conclusion: The volume-rendering technique facilitates the evaluation of cerebral time-of-flight MR angiography data sets and allows better detection and more reliable characterization of intracranial aneurysms than does maximum intensity projection.

Objective: The purpose of our study was to evaluate the role of multidetector CT (MDCT) angiography with volume rendering for estimating the patency of renal artery stents., Subjects and Methods: In 16 patients, 16 renal artery stents were evaluated with MDCT renal angiography and digital subtraction angiography (DSA). CT data were evaluated using multiplanar volume reformations and the volume-rendering algorithm with three different volume-rendered parameter settings (low-to-high, high-to-low, and high-low-high opacity transfer functions: VR(LH), VR(HL), and VR(VE), respectively). Targeted images of each stent were rendered in paraaxial and paracoronal planes and were interactively interpreted. The overall restenosis severity was measured on postprocessed paraaxial and paracoronal images and compared with that obtained on DSA using linear regression analysis. Image quality and lumen delineation on rendered images were also compared using Wilcoxon's signed rank test., Results: Eight restenoses were identified on DSA. Correlations between restenosis severity measured with DSA and those measured with MDCT were significant (p < 0.001). Volume rendering with VR(HL) allowed the best correlation with DSA (reviewer 1, r(2) = 0.86; reviewer 2, r(2) = 0.94) and was significantly better than multiplanar volume reformations (p = 0.028). Overall image quality was high with all rendering techniques and with no significant differences (p > 0.59, for all comparisons). Stent lumen was well delineated with volume-rendering modalities; however, VR(HL) was significantly better than VR(LH) (p = 0.033)., Conclusion: Volume-rendered MDCT angiography enabled high-quality three-dimensional reproducible evaluation of the patency of implanted renal artery stents. Volume rendering with VR(HL) achieved the best performance.

We assessed the clinical utility of the volume-rendering (VR) algorithm as a postprocessing technique of intracranial magnetic resonance angiography (MRA) for the evaluation of cerebrovascular disease in comparison with the maximum intensity projection (MIP) algorithm. VR and MIP images were compared with digital subtraction angiography (DSA). Volume-rendered views improved the perceptibility of intracranial vasculature and consequently augmented diagnostic confidence, improved the characterization of underlying vascular pathologies, and facilitated image interpretation. Volume rendering has the potential to expand the role of cerebral MRA in the diagnostic investigation and treatment planning of cerebrovascular disease.

Stress fractures may pose a diagnostic dilemma for radiologists since they are sometimes difficult to demonstrate on plain films and may simulate a tumour. They were first described in military personnel and professional athletes. Recently, there is an increasing incidence in the general population due to increasing sportive activities. Stress fractures occur most often in the lower extremities, especially in the tibia, the tarsal bone, the metatarsal bone, the femur and the fibula. In the upper extremities, they are commonly found in the humerus, the radius and the ulna. Some fractures of the lower extremities appear to be specific for particular sports, for example, fractures of the tibia affect mostly distance runners. Whereas stress fractures of the upper extremities are generally associated with upper limb-dominated sports. A correct diagnosis requires a careful clinical evaluation. The initial plain radiography may be normal. Further radiological evaluation could be performed by means of computerised tomography, magnetic resonance imaging and bone scanning. The latter two techniques are especially helpful for establishing a correct initial diagnosis.

Objective: The aim of this study was to evaluate the feasibility, safety, and effectiveness of endovascular stent-graft placement for the emergency treatment of acute descending thoracic aortic disease., Materials and Methods: From January 1996 through November 2001, 18 patients underwent emergency endovascular stent-graft placement for various types of acute descending thoracic aortic disease. Five patients had Stanford type B aortic dissection, six had traumatic ruptures of the thoracic aorta, five had ruptured aortic aneurysms, and two had penetrating atherosclerotic aortic ulcers. All patients presented with life-threatening symptoms requiring treatment with stent-grafts from the emergency kit. All were at high surgical risk due to serious comorbidities. The efficacy of the procedure was assessed at follow-up studies before discharge and at 3, 6, and 12 months after intervention and yearly thereafter., Results: The primary technical success rate was 78%. Four patients had primary perigraft leaks. The secondary technical success rate was 83%. One patient died 20 hr after intervention from stent-graft-related causes. Follow-up studies revealed stent-graft migration in one patient. Progression of disease was observed in one patient treated for dissection and in both patients treated for penetrating ulcers. One patient died 7 months after intervention of unknown reasons; all other patients are alive. The mean follow-up time was 17.4 months (range, 0-38 months)., Conclusion: Emergency repair of acute descending thoracic aortic disease with stent-graft placement can be successfully accomplished and may be a promising alternative to open-chest surgery, especially in patients at high risk.

Purpose: The purpose of study was to compare patient dose applying singleslice- and multislice-spiral CT., Methods: The examinations were performed with a singleslice-spiral CT (Highspeed Advantage; GE Medical Systems; Milwaukee, USA) and with a multislice CT systems (LightSpeed QX/i GE Medical Systems; Milwaukee, USA). For the determination of the radiation exposure (absorbed dose) a selection of most executed protocols (thorax-helical, abdomen-helical, petrous bone-axial, head-axial) were simulated using an Alderson Rando Phantom. The dose was determined by means of lithiumfluorid-thermoluminiscence dosimeters (TLD-GR 200)., Results: For thorax and abdomen protocols higher energy dose values could be found using a multislice CT. On the average the energy dose values were increased by 2.6 on an average in relation to single slice spiral CT. The energy dose values of the multisclice CT using head protocols could be reduced by 30% in relation to single slice spiral CT due to suitable parameter selections. The energy dose applying a petrous bone protocol resulted in an average increase by a factor 1.5 using a multislice CT., Conclusion: Using the new multislice CT technique protocol strategies must be optimized regarding the patient doses. Users can operate critically in the sense of the radiation protection only if they are aware of the occurring dose amounts to the patient.