(18)F-FDG PET and conventional imaging for assessment of Hodgkin's disease and non Hodgkin's lymphoma. An analysis of 193 patient studies.

UNLABELLED: The AIM of this study was to assess the diagnostic value of FDG-PET and conventional imaging (CI) in a large series of patient with Hodgkin's disease (HD) or non-Hodgkin's lymphoma (NHL) at three time points during their course of disease. PATIENTS, METHODS: 169 consecutive lymphoma patients (69 HD; 100 NHL) were included. 193 FDG-PET studies were performed for staging at baseline in 42 cases, for post-therapeutic monitoring in 103, and for diagnosis of recurrence in 48 cases. Performance indices of sensitivity, specificity, positive (PPV) and negative predictive value (NPV), and accuracy of metabolic FDG-PET and morphological CI were calculated. Differences in staging and diagnosis of residual or recurrent lymphoma were compared. RESULTS: FDG-PET changed staging in 36% of cases for staging at baseline, in 52% of cases for monitoring response to treatment, and in 29% for diagnosis of recurrence. FDG-PET staging results were confirmed in 80% for staging at baseline, in 74% for monitoring response to treatment, and in 50% for diagnosis of recurrence. FDGPET and CI differed significantly at monitoring response to treatment for sensitivity (0.91 versus 0.69; p < 0.02), specificity (0.90 versus 0.38; p < 0.00001), PPV (0.77 versus 0.42; p < 0.001), and accuracy (0.83 versus 0.55; p < 0.02). CONCLUSION: FDG-PET should be considered as the diagnostic modality of choice for post-therapeutic assessment of lymphoma patients and may be a reliable alternative to CI for staging at baseline and diagnosis of recurrence.

Whole-body MRI in comparison to skeletal scintigraphy in detection of skeletal metastases in patients with solid tumors.

AIM: To evaluate the diagnostic value of whole-body magnetic resonance imaging (MRI) and skeletal scintigraphy in the detection of skeletal metastases in patients with solid tumors. MATERIALS AND METHODS: One hundred and twenty-nine tumor patients were examined with whole-body MRI using coronal TIRM sequences for the different anatomical regions. Skeletal scintigraphy was performed with 99mTc-DPD. RESULTS: In 105/129 (81%) patients, the whole-body MRI and skeletal scintigraphy findings were concordant. In 56/129 (43%) patients, both imaging modalities excluded skeletal metastases. In 49/129 (38%) patients, whole-body MRI and skeletal scintigraphy revealed metastases, however whole-body MRI demonstrated more extensive disease in 22/49 (45%) cases. In 6/49 (12%) cases, skeletal scintigraphy was superior to whole-body MRI in detecting more skeletal metastases. In 24/129 (19%) cases, the imaging findings were discordant. In 15 cases, skeletal scintigraphy was negative, whereas whole-body MRI revealed skeletal metastases. In 9 cases, skeletal scintigraphy was positive, whereas whole-body MRI failed to detect these metastases. In 77/129 (60%) patients, whole-body MRI revealed additional tumor-related findings. CONCLUSION: Whole-body MRI, as a new staging method, is superior to skeletal scintigraphy with respect to the detection of skeletal metastases and the extent of metastastic disease. Furthermore, whole-body MRI yields additional tumor-related findings. Therefore, whole-body MRI should be performed as an alternative to skeletal scintigraphy for the assessment of skeletal metastases.

Computed tomography and 18F-FDG positron emission tomography for therapy control of Hodgkin's and non-Hodgkin's lymphoma patients: when do we really need FDG-PET?

BACKGROUND: The aim of this study was to evaluate the accuracy of computed tomography (CT) and [(18)F]fluoro-deoxy-d-glucose positron emission tomography (FDG-PET) for prediction of progression-free survival of Hodgkin's disease (HD) and non-Hodgkin's lymphoma (NHL) patients after completion of therapy. PATIENTS AND METHODS: CT and FDG-PET were performed in 40 HD, 17 indolent NHL and 44 aggressive NHL patients (29 women, 72 men; aged 41+/-14 years) in a median of 2 months after therapy. Progression-free survival was evaluated using the Kaplan-Meier method. Independent prognostic factors were identified by means of Cox proportional hazards model. RESULTS: CT imaging results were progressive disease (PD) in five, stable disease (SD) in 57, and partial response (PR) or complete remission (CR) in 39 patients. FDG-PET suggested residual lymphoma in 24 patients. Three-year progression-free survival rates after exclusion of five PD patients were: 100% (PET negative; CT: PR or CR), 81% (PET negative; CT: SD), 21% (PET positive; CT: SD) and 0% (PET positive; CT: PR). FDG-PET (P<0.0001) and bulky disease (P <0.05) were identified as independent prognostic variables. CONCLUSIONS: Among lymphoma patients with PR and SD on CT, FDG-PET discriminated those destined to progress into a low risk of < or =20% and a high risk for recurrence of > or =80%.

[Whole-body MRI in comparison to skeletal scintigraphy for detection of skeletal metastases in patients with solid tumors]. / Ganzkörper-MRT vs. Skelettszintigraphie bei der Detektion ossärer Metastasen solider Tumoren.

PURPOSE: The aim of this study was to compare the diagnostic efficacy of whole-body magnetic resonance imaging (WB-MRI) as a new and rapid examination technique with skeletal scintigraphy for detection of skeletal metastases from solid tumors. MATERIAL AND METHODS: In 129 patients with solid malignant tumors, WB-MRI was performed for individual comparison with skeletal scintigraphy. Examinations were performed with the innovative AngioSURF rolling table with integrated phased array surface coil and coronary TIRM sequences for different body regions. RESULTS: The results for WB-MRI and skeletal scintigraphy were concordant in 81% of the cases, whereby both procedures excluded skeletal metastases in 43%. WB-MRI and skeletal scintigraphy demonstrated skeletal metastases in 38% of the cases, whereby WB-MRI provided more comprehensive findings in 45%. In 12% of the cases, skeletal scintigraphy was superior to WB-MRI and in 19% the findings were discordant, whereby WB-MRI detected skeletal metastases in 15 cases which had not been found on skeletal scintigraphy. In nine cases, skeletal scintigraphy was positive when the WB-MRI was negative. In 60% of the cases, WB-MRI evidenced tumor-associated findings. CONCLUSION: WB-MRI represents a promising new staging technique for detection of skeletal metastases, which is more sensitive in many cases than skeletal scintigraphy in detecting and assessing the extent of skeletal metastases-and tumor-associated findings that are relevant for treatment strategy.

MRI-diffusion imaging of neuroblastomas: first results and correlation to histology.

The purpose of this study was to evaluate diffusion-weighted MR imaging in neuroblastomas. We prospectively examined seven children (age range 1-3 years) with seven solid body neuroblastomas. Diagnosis was established histologically. Diffusion-weighted echo-planar imaging (EPI) sequence was performed in all patients, with a repetition time of 5400 ms and an echo time of 103 ms, and with a b-value of 1000 s/mm(2). The contrast of tumour tissue depicted with T2-weighted images and diffusion-weighted images were evaluated by means of region-of-interest measurements and a calculation of the apparent diffusion coefficient (ADC) was done. The ADC calculation showed a mean ADC of 1.1x10(-3) (SD 0.14x10(-3), range 0.9-1.2x10(-3)) mm(2)/s of all tumours. Diffusion-weighted images showed an increased tumour signal. Water proton diffusion within the tumour matrix of neuroblastomas is especially restricted by the molecular and macromolecular barriers due to the very dense structure of this tumour tissue. We hypothesize that high nuclear-to-cytoplasm ratio of neuroblastoma cells limits intracellular motion. Furthermore, the very densely packed tumour cells inhibit effective motion of extracellular water protons. Restricted proton motion leads to a reduction in the rate of apparent diffusion and to a marked increase in signal on diffusion-weighted EPI MR images.

Contrast enhanced MR angiography in the assessment of relevant stenoses in occlusive disease of the pelvic and lower limb arteries: diagnostic value of a two-step examination protocol in comparison to conventional DSA.

INTRODUCTION/OBJECTIVES: Contrast-enhanced MRA (ce-MRA) has been claimed by many authors as a replacement of conventional angiography evaluating peripheral arterial occlusive disease. However, reliable detection of relevant stenoses (>70%) has to be provided for planning vascular interventions. Only few data in the literature focuses on this crucial problem. The purpose of this study was to evaluate this topic using a two-step body-coil-based MRA protocol. METHODS AND PATIENTS: Forty three patients presenting with 82 stenoses >/=50% and 61 stenoses >70% on conventional catheter angiogram received fast Gadolinium-DTPA-enhanced high resolution 3D MR angiography at 1.5 T covering the pelvic and peripheral vascular tree in two examination steps using the body-coil. The data were evaluated double-blinded by three readers distinguishing moderate (50-70%) from severe stenoses (>70%). RESULTS: Overall sensitivity/specificity/accuracy was 84/60/70% evaluating 143 segments. Specificity was rather poor in the iliac (58%) and crural (50%) region and moderate in the femoral and popliteal level (73%). The negative predictive value ranged between 78 and 91%. The grade of stenosis tend to be overestimated rather than underestimated in all levels with positive predictive values between 55 and 78%. DISCUSSIONS AND CONCLUSIONS: Body-coil-based contrast-enhanced MRA has limited potential in distinguishing moderate from severe stenoses in peripheral occlusive disease. Overestimations are more common than underestimations. Both occur mainly in small-sized crural arteries but also in larger iliac arteries where vessel course in partition direction may cause inadequacy between voxel size and lumen diameter in severe stenosis.

Epithelioid angiosarcoma of the aorta.

Primary malignant tumors of the aorta are extremely rare. Review of the literature indicates that there are nearly 100 recorded cases of primary malignant tumors of the aorta. The purpose of this article is to present an additional case of the primary malignant tumors of the aorta which initially has been misinterpretated as atherosclerosic disease. This aortic tumor was of endothelial origin and immunohistochemical studies classified the tumor as an epithelioid angiosarcoma. The treatment resulted in an abdominal aortic repair. MRI of the spine revealed multifocal metastatic disease of the axial skeleton and a subsequent chemotherapy was performed. The patient died 17 months after the initial diagnosis.

Comparative detectability of bone metastases and impact on therapy of magnetic resonance imaging and bone scintigraphy in patients with breast cancer.

OBJECTIVE: to evaluate the comparative impact of magnetic resonance imaging and bone scintigraphy in bone metastases of breast cancer. METHODS AND PATIENTS: in 81 patients with histologically proven breast cancer magnetic resonance imaging of the axial skeleton and whole-body bone scintigraphy had been performed. Images were retrospectively reviewed and compared for detection of metastases, extent of metastatic disease and therapeutic implications according to the patients' records. RESULTS: about 54/81 (67%) patients revealed bone metastases. In 7/54 (13%) patients with bone metastases, scintigraphy was false negative. In one patient a solitary sternal metastases was seen. In 26/53 [49%] patients with spinal metastases, magnetic resonance imaging showed more extensive disease. Local radiotherapy or surgery was indicated in ten patients with metastases not evident in bone scintigraphy, in 20 patients with positive results by both imaging modalities and in six patients with metastases of pelvis imaged by bone scintigraphy only. CONCLUSION: magnetic resonance imaging of the axial skeleton and pelvis appears superior for staging as only one patient had metastases merely outside the axial skeleton and local therapy was indicated even in spinal regions negative in bone scintigraphy.

Whole-body 18F dopa PET for detection of gastrointestinal carcinoid tumors.

PURPOSE: To evaluate fluorine 18 (18F) dopa positron emission tomography (PET) in comparison with established imaging procedures in gastrointestinal carcinoid tumors. MATERIALS AND METHODS: After evaluation of the normal distribution of 18F dopa, 17 patients with histologically confirmed tumors were examined with 18F dopa PET. Results of 2-[fluorine 18]fluoro-2-deoxy-D-glucose (FDG) PET, somatostatin-receptor scintigraphy, and morphologic imaging (computed tomography and/or magnetic resonance imaging) were available for all patients. Results of the procedures were evaluated by two radiologists and two nuclear medicine specialists, whose consensus based on all available histologic, imaging, and follow-up findings was used as the reference standard. RESULTS: Ninety-two tumors were diagnosed: eight primary tumors, 47 lymph node metastases, and 37 organ metastases. 18F dopa PET led to 60 true-positive findings (seven primary tumors, 41 lymph node metastases, 12 organ metastases); FDG PET, 27 (two primary tumors, 14 lymph node metastases, 11 organ metastases); somatostatin-receptor scintigraphy, 52 (four primary tumors, 27 lymph node metastases, 21 organ metastases); and morphologic imaging, 67 (two primary tumors, 29 lymph node metastases, 36 organ metastases). This resulted in the following overall sensitivities: 18F dopa PET, 65% (60 of 92); FDG PET, 29% (27 of 92); somatostatin-receptor scintigraphy, 57% (52 of 92); morphologic procedures, 73% (67 of 92). Although the morphologic procedures were most sensitive for organ metastases, 18F dopa PET enabled best localization of primary tumors and lymph node staging. CONCLUSION: 18F dopa PET is a promising procedure and useful supplement to morphologic methods in diagnostic imaging of gastrointestinal carcinoid tumors.

Extent and time course of morphological changes of bone marrow induced by granulocyte-colony stimulating factor as assessed by magnetic resonance imaging of healthy blood stem cell donors.

The aim of this study was to assess the time course and extent of signal alterations of red bone marrow after short-term stimulation by recombinant human granulocyte-colony stimulating factor (rHuG-CSF) in healthy peripheral blood stem cell donors using magnetic resonance imaging (MRI) at low-field strength. Twelve healthy blood stem cell donors without evidence of bone marrow disorders were prospectively investigated and underwent four MRI studies of their lumbar spine. Sagittal T1- and T2-weighted spin-echo sequences and a gradient-echo (GE) sequence with an echo time for out-of-phase imaging were performed prior to rHuG-CSF application (baseline MRI), on the day of first stem cell harvest (after 70 microg/kg body weight rHuG-CSF, second MRI) followed by two studies 9-18 days (median 14.5 days, third MRI) and 26-48 days (median 39.5 days, fourth MRI) after discontinuation of rHuG-CSF application. Baseline MRI showed normal marrow signal in all patients. The second MRI revealed a decrease of quantified bone marrow signal relative to nucleus pulposus in T1- and T2-weighted images and an increase of relative signal in out-of-phase GE sequences. The greatest changes of relative marrow signal were observed at the third MRI. Compared to baseline MRI, relative marrow signal was diminished by 12% in T1-weighted images and increased by 59% in GE sequences, consistent with a rise in marrow cellularity simulating diffuse marrow disease. At the fourth MRI quantified relative marrow signal returned to baseline levels in all sequences. In healthy individuals rHuG-CSF application leads to significant signal changes of bone marrow in lumbar vertebra that are maximal about 2 weeks after discontinuation of rHuG-CSF application. In patients with underlying marrow disorders who receive hematopoietic growth factors during treatment, these changes should not be confused with disease progression.

Breathhold unenhanced and gadolinium-enhanced magnetic resonance tomography and magnetic resonance cholangiography in hilar cholangiocarcinoma.

We assessed the imaging characteristics of hilar cholangiocarcinoma in magnetic resonance imaging (MRI) and magnetic resonance cholangiography (MRC). Breathhold MRI (T2-weighted turbo spin echo sequences, unenhanced T1-weighted gradient echo sequences, and gadolinium-enhanced fat-suppressed gradient echo sequences) and breathhold MRC (fat-suppressed two-dimensional projection images) performed in 12 patients with histologically confirmed hilar cholangiocarcinoma were retrospectively reviewed for morphological tumor characteristics and contrast enhancement patterns. MRC demonstrated a significant bile duct stenosis with intrahepatic bile duct dilatation in all cases except in one patient who received an endoprothesis prior to imaging. Hilar cholangiocarcinoma was diagnosed by MRC only in one patient and MRI and MRC in 11. Mass lesions were seen in nine patients and circumferential tumor growth in three, including the patient diagnosed by MRC only. The tumor appeared hypointense relative to liver parenchyma in 10 of 11 patients in unenhanced T1-weighted images. T2-weighted sequences showed isointense or only slightly hyperintense signal in 5 of 11 patients, 3 of whom demonstrated desmoplastic reactions by histology. The other 6 patients revealed strongly hyperintense signal intensities. Contrast enhancement was increased compared to liver in 5 of 11 patients and decreased in 6 of 11 patients. MRI with MRC seem to be a sensitive tools in the detection of hilar cholangiocarcinomas. The variable imaging characteristics are most probably related to the inhomogeneous histological appearance of this tumor entity.

Increased metabolic activity in the thymus gland studied with 18F-FDG PET: age dependency and frequency after chemotherapy.

UNLABELLED: This study was designed to evaluate the age dependency of 18F-FDG uptake in the thymus and the frequency of PET confirmation of thymus hyperplasia after chemotherapy in cancer patients. METHODS: Whole-body FDG PET recordings of 168 patients were retrospectively examined for a retrosternal lesion in the anterior mediastinum that was attributable to the thymus. The patients were assigned to the following four groups: children with malignant lesions before the first therapy (group Ia; n = 15; mean age +/- SD, 11.9 +/- 3.7 y), children with malignant disease after chemotherapy (group Ib; n = 12; mean age, 10.3 +/- 5.0 y), adults with histologically confirmed malignant lymphoma before the first therapy (group IIa; n = 37; mean age, 43.9 +/- 16.7 y), and adult lymphoma patients 3 wk to 4 mo after chemotherapy (group IIb; n = 104; mean age, 40.9 +/- 14.6 y). RESULTS: Increased FDG accumulation in the thymus was seen in 11 patients (73%) of group Ia and 9 patients (75%) of group Ib. Thymus hyperplasia was found in 5 patients (5%) of group IIb. The eldest of these 5 patients was 25 y old. No increased FDG accumulation in the thymus was observed in any of the group IIa patients. In cases of visible FDG uptake in the thymus, standardized uptake values did not exceed 4. CONCLUSION: FDG accumulation in the thymus is a common finding in children and can occasionally be observed in young adults after chemotherapy. Knowledge of the characteristics of a typical retrosternal lesion in conjunction with the clinical history allows avoidance of diagnostic uncertainty and unnecessary procedures.

2-(fluorine-18)fluoro-2-deoxy-D-glucose positron emission tomography in the detection and staging of malignant lymphoma. A bicenter trial.

BACKGROUND: The authors undertook a prospective evaluation of the clinical value of 2-fluoro [18-]-2-deoxyglucose positron emission tomography (FDG-PET) in the detection and staging of malignant lymphoma compared with computed tomography (CT) and bone marrow biopsy (BMB). METHODS: Fifty-two consecutive patients with untreated malignant lymphoma were evaluated prospectively in a bicenter study. FDG-PET, CT, and BMB were performed for investigating lymph node/extranodal manifestations and bone marrow infiltration. Thirty-three percnt of the discrepant results were verified by biopsy, magnetic resonance imaging, or clinical follow-up (range, 4-24 month). RESULTS: Altogether, 1297 anatomic regions (lymph nodes, organs, and bone marrow) were evaluated. FDG-PET and CT scans were compared by receiver operating characteristic (ROC) curve analysis. The area under the ROC curve were as follows: lymph nodes, 0.996 (PET) and 0.916 (CT); extranodal, 0.999 (PET) and 0.916 (CT); supradiaphragmatic, 0.996 (PET) and 0.905 (CT); and infradiaphragmatic, 0.999 (PET) and 0.952 (CT). In these analyses, FDG-PET was significantly superior to CT (P < 0.05), except in infradiaphragmatic regions, in which the two methods produced equivalent results. In detecting bone marrow infiltration, FDG-PET was superior to CT and was equivalent to BMB. In 4 of 52 patients (8%), FDG-PET led to an upstaging and a change of therapy. CONCLUSIONS: Noninvasive FDG-PET is very accurate in the staging of malignant lymphoma. Compared with standard staging modalities (CT and BMB), PET was significantly superior and led to changes in the therapy regimen for 8% of patients.

The knee joint in early juvenile idiopathic arthritis. An ROC study for evaluating the diagnostic accuracy of contrast-enhanced MR imaging.

PURPOSE: Diagnosis of juvenile idiopathic arthritis (JIA) remains difficult due to unspecific clinical and laboratory findings, especially in early stages of the disease. The purpose of our study was to determine the sensitivity and specificity of MR imaging in diagnosing JIA of the knee joints. MATERIAL AND METHODS: Forty children (3-17 years old) clinically diagnosed with JIA (follow-up > 1 year) of a knee joint and a control group of 40 children with painful knee joints (MR diagnosis: bone bruise of the knee (n = 7), normal knee joint (n = 12), osteomyelitis (n = 6), septic arthritis (n = 2), bone tumor (n = 7) and miscellaneous bone lesions (n = 6)) were examined using a 1.5 T MR unit. T1-weighted spin-echo (SE), T2-weighted fast SE, contrast-enhanced T1-weighted SE and 2D gradient echo sequences were performed. The receiver operating characteristic (ROC) curves evaluation was conducted by 5 independent radiologists. RESULTS: The positive criteria for diagnosing JIA were joint effusions (n = 40), contrast-enhancing synovitis (n = 39), cartilage lesions (n = 15), subchondral erosions and bony destruction (n = 1). Sensitivity and specificity were 93.5% and 92.5%, respectively. Both cases of septic arthritis were misdiagnosed as JIA by all radiologists. CONCLUSION: Contrast-enhanced MR imaging seems to be a highly sensitive tool in establishing the diagnosis of JIA.

18F-DOPA positron emission tomography for tumour detection in patients with medullary thyroid carcinoma and elevated calcitonin levels.

In spite of the availability of numerous procedures, diagnostic imaging of tumour manifestations in patients with medullary thyroid carcinoma and elevated calcitonin levels is often difficult. In the present study, the new procedure of fluorine-18 dihydroxyphenylalanine positron emission tomography (18F-DOPA PET) was compared with the established functional and morphological imaging methods. After evaluation of the normal distribution of 18F-DOPA, 11 patients with medullary thyroid carcinoma were examined using 18F-DOPA PET. Results of 18F-fluorodeoxyglucose (18F-FDG) PET, somatostatin receptor scintigraphy (SRS) and morphological tomographic imaging (CT/MRI) were available for all patients. All individual procedures were evaluated without reference to prior information. Data assessment for each patient was based on cooperation between experienced radiologists and specialists in nuclear medicine, who considered all the available findings (histological results, imaging, follow-up studies). This cooperation served as the gold standard against which the results of the individual procedures were evaluated. A total of 27 tumours were studied [three primary tumours (PT)/local recurrence (LR), 16 lymph node metastases (LNM) and eight organ metastases (OM)]. 18F-DOPA PET produced 17 true-positive findings (2 PT/LR, 14 LNM, 1 OM), 18F-FDG PET 12 (2 PT/LR, 7 LNM, 3 OM), SRS 14 (2 PT/LR, 8 LNM, 4 OM) and morphological imaging 22 (3 PT/LR, 11 LNM, 8 OM). The following sensitivities were calculated with respect to total tumour manifestations: 18F-DOPA PET 63%, 18F-FDG PET 44%, SRS 52%, morphological imaging 81%. Thus, the morphological imaging procedures produce the best overall sensitivity, but the specificity for PT/LR (55%) and LNM (57%) was low. With respect to lymph node staging, the best results were obtained with 18F-DOPA PET. 18F-DOPA PET is a new functional imaging procedure for medullary thyroid carcinoma that seems to provide better results than SRS and 18F-FDG PET. Moreover, the data indicate that no single procedure provides adequate diagnostic certainty. Therefore, 18F-DOPA PET is a useful supplement to morphological diagnostic imaging, improving lymph node staging and enabling a more specific diagnosis of primary tumour and local recurrence.

Optimization of contrast-enhanced MR angiography of the hands with a timing bolus and elliptically reordered 3D pulse sequence.

Our objective was to optimize bolus administration and sequence setting in gadolinium-enhanced magnetic resonance (MR) angiography of the hands. Elliptically reordered three-dimensional (3D) spoiled gradient-echo sequence with non-slab-selective radio frequency excitation was optimized according to the measurements of arterial and venous time-signal curves in 21 patients. Great variations in bolus arrival time and arterio-venous transit time could be observed. In most patients high-quality arterial depiction could be obtained with minor venous contamination. Contrast-to-noise, spatial resolution, and selective arterial filling is still a challenge for 3D MR angiography of the hand but can be optimized using Gadolinium-BOPTA and a dedicated pulse sequence setting with exact bolus timing.

[Preoperative examination of potential kidney transplantation donors: value of gadolinium-enhanced 3D MR angiography in comparison with DSA and urography]. / Präoperative Untersuchung potentieller Nierenlebendspender: Wertigkeit der Gadoliniumverstärkten 3D-MR-Angiographie im Vergleich mit der DSA und Urographie.

PURPOSE: To assess a contrast-enhanced standardized MRA protocol for the presurgical evaluation of potential renal transplant donors. METHODS: Twenty-three potential donors for renal transplantations were examined with gadolinium-enhanced, two-phase MR angiograms (1.5 T) and DSA/urography for the number of renal arteries, the presence of aberrant arterial and venous branches, renal artery stenoses and anatomy of the renal collecting system and ureters. The diagnostic value was assessed by evaluating different image processing modalities and interobserver variability. RESULTS: Using maximum intensity projections (MIP) together with multiplanar reformatting (MPR), accessory arteries were detected with a sensitivity/specificity of 100%/98%. Depending on diagnostic experience, exclusive evaluation of MIP yielded a sensitivity/specificity of 67-100%/95-100%. Using MIP/MPR, venous depiction was good in 80%, with MIP solely in 30-40%. At least the proximal third of the ureter was visible in 67%. CONCLUSION: MPR/MIP evaluation of two-phase, contrast-enhanced MRA provides an excellent depiction of renal vessel anatomy for presurgical evaluation of renal transplant donors. Exclusive MIP assessment is less reliable and depends strongly on the examiner's experience. For sufficient visualization of the ureters, either additional measurements or low-dose diuretic injection have to performed.

Chest wall infiltration by lung cancer: value of thin-sectional CT with different reconstruction algorithms.

The aim of this investigation was to evaluate whether thin-sectional CT with different reconstruction algorithms can improve the diagnostic accuracy with regard to chest wall invasion in patients with peripheral bronchogenic carcinoma. Forty-one patients with intrapulmonary lesions and tumor contact to the thoracic wall as seen on CT staging underwent additional 1-mm CT slices with reconstruction in a high-resolution (HR) and an edge blurring, soft detail (SD) algorithm. Five criteria were applied and validated by histological findings. Using the criteria of the intact fat layer, HRCT had a sensitivity of 81 % and a specificity of 79 %, SD CT had a sensitivity of 96 % and a specificity of 78 %, and standard CT technique had a sensitivity of 50 % and a specificity of 71 %, respectively. Regarding changes of intercostal soft tissue, HRCT achieved a sensitivity of 71 % and a specificity of 96 %, SD CT had a sensitivity of 94 % and a specificity of 96 % (standard CT technique: sensitivity 50 % and specificity 96 %). For the other criteria, such as pleural contact area, angle, and osseous destruction, no significant differences were found. Diagnostic accuracy of chest wall infiltration can be improved by using thin sectional CT. Especially the application of an edge-blurring (SD) algorithm increases sensitivity and specificity without additional costs.