[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.

Impact of 18F-FDG-positron emission tomography for decision making in colorectal cancer recurrences.

Diagnostic imaging for suspected tumour recurrence of primary colorectal cancer frequently lacks specificity and sensitivity. The impact of whole body 18F-FDG-positron-emission tomography (PET) on detection of local recurrences and hepatic or pulmonary metastases was evaluated in a prospective study. Results were compared with computed tomography (CT), ultrasonography, magnetic resonance imaging and conventional chest X-ray. The study included 71 patients (77 investigations) with suspected local recurrence, hepatic metastases or unexplained raised level of the tumour marker carcinoembryonic antigen (CEA). The results demonstrate that 18F-FDG-PET was clearly superior to CT with regard to detection of hepatic metastases. Sensitivity was 1.0 and specificity 0.98 compared with 0.87 and 0.91 for CT. In four cases, 18F-FDG-PET clarified otherwise unclear local recurrences. In five patients, 18F-FDG-PET showed pulmonary metastases that had previously been unknown. In a total of 16 patients (20.8%), 18F-FDG-PET provided additional information leading to a change of the treatment strategy. 18F-FDG-PET clearly has the ability to detect colorectal tumour recurrence and its metastases in a whole body format. Therefore, it may be applied in the follow-up of patients with primary colorectal cancer. Despite the costs, it is certainly recommended for patients with an otherwise unclear increase of CEA level or with unproven local recurrence.

Real-time interactive virtual endoscopy of the tracheo-bronchial system: influence of CT imaging protocols and observer ability.

OBJECTIVE: To evaluate the influence of different spiral CT examination protocols suitable for clinical use on image quality and to assess the observer dependence in interactive real-time virtual bronchoscopy. METHODS AND PATIENTS: Real-time perspective volume rendering of the airways in twenty normal patients based on four different spiral CT examination protocols was evaluated by four observers in regard to the order of depictable bronchi. RESULTS: Best results were obtained using an examination protocol with a small beam collimation and a maximum pitch. Depending on the observer's ability to control the fly path and the orientation of the bronchi with respect to the slice plane up to sixth order bronchi could be depicted. Inter-observer variability was up to two branching orders. CONCLUSION: The performance of virtual bronchoscopy strongly depends on the applied CT examination protocol and the observers experience with perspective volume rendering. Both of which have to be taken into account when virtual bronchoscopy is compared with fiberoptic bronchoscopy.

Pelvic imaging with a selenium-based detector (Thoravision). Comparison with screen-film radiography in 75 patients.

OBJECTIVE: To evaluate whether the selenium detector (Thoravision) provides sufficient diagnostic confidence in digital pelvic imaging compared with a conventional screen-film combination. METHODS: In 75 patients, pelvic imaging with conventional screen-film and isodose selenium radiography using a dedicated postprocessing mode was compared independently by three radiologists. The depiction of cortical and cancellous bone was evaluated in the iliac wings, sacral and pubic bones, acetabulum, femoral head, and trochanter. Demarcation of soft tissue was assessed in the iliac and trochanteric region. RESULTS: Visualization of cortical bone and soft tissue in the iliac area as well as soft tissue and cortical and cancellous bone in the trochanteric region was significantly superior with the selenium detector. However, conventional imaging was better in the trabecular bone of the sacral region, where results with the selenium system were particularly poor. CONCLUSIONS: The selenium detector (Thoravision) is advantageous in imaging soft tissue adjacent to the iliac wings and the trochanter, but results for the cancellous sacral bone are poor. Further modifications of postprocessing modes may lead to improved depiction of this critical pelvic area.

Comparison between a screen-film system and a selenium radiography system. An ROC study using simulated thoracic lesions.

RATIONALE AND OBJECTIVES: To evaluate the diagnostic image quality of the hard copies of a commercially available selenium detector-based computed radiography system compared to that of a conventional screen-film system. METHODS: Ten radiographs of an anthropomorphic chest phantom with simulated nodular and linear-reticular lesions were produced using either system. Each radiograph was subdivided into 15 fields containing zero lesions, one nodular lesion, one linear-reticular lesion, or both lesions. The total of 150 fields for each modality was reviewed by six radiologists, and receiver operating analysis was performed. RESULTS: The conventional screen-film system performed significantly better for nodular lesions, whereas no statistically significant difference was found between the detection rates of both systems for linear-reticular lesions. CONCLUSIONS: The better detection of nodules with the dedicated selenium detector can be explained by the higher dynamic range of the system. Detection of linear-reticular lesions was slightly but not significantly better with the screen-film system, but the detection rate of the selenium detector might be further improved with a different image processing technique.

Evaluation of positron emission tomography with 2-[18F]fluoro-2-deoxy-D-glucose for the differentiation of chronic pancreatitis and pancreatic cancer.

BACKGROUND: The clinical presentation of patients with pancreatic cancer may resemble the clinical picture of chronic pancreatitis. A definitive preoperative diagnosis is not always obtained in patients with a history of chronic pancreatitis despite the use of modern imaging techniques. Operative strategy therefore remains unclear before operation in these patients. METHODS: Positron emission tomography (PET) with 2-[18F]fluoro-2-deoxy-D-glucose (FDG) was introduced recently into clinical oncology because of its ability to demonstrate metabolic changes associated with various disease processes. The impact of FDG-PET on the differentiation of chronic pancreatitis and pancreatic cancer was investigated. FDG-PET was performed in 48 patients with chronic pancreatitis (n = 12), acute pancreatitis (n = 3) and pancreatic cancer (n = 27), and in controls (n = 6). Histological examination was undertaken in all cases except controls. The FDG-PET results were obtained without knowledge of results of other imaging procedures. The results were then compared with those of computed tomography, ultrasonography, endoscopic retrograde cholangiopancreaticography, operative findings and histology. PET images were analysed semiquantitatively by calculating a standard uptake value (SUV) 90-120 min after application of the tracer. RESULTS: Cut-off values were validated as follows: SUV greater than 4.0 for pancreatic cancer, SUV of 3.0-4.0 for chronic pancreatitis, and SUV of less than 3.0 for controls. Sensitivity and specificity of PET imaging were 0.96 and 1.0 for pancreatic cancer, and 1.0 and 0.97 for chronic pancreatitis. In five cases only FDG-PET led to the correct preoperative diagnosis. CONCLUSION: The results give further evidence that FDG-PET is an important non-invasive method for the differentiation of chronic pancreatitis and pancreatic cancer. Delayed image acquisition in the glycolysis plateau phase permits improved diagnostic performance. This imaging technique is extremely helpful before operation in patients with an otherwise unclear pancreatic mass, despite its costs.

[3-phase bone scintigraphy: perfusion and vitality of the femur head after media femoral neck fracture and osteosynthesis]. / 3-Phasen-Skelettszintigraphie: Perfusion und Vitalität des Hüftkopfes nach medialer Schenkelhalsfraktur und Osteosynthese.

UNLABELLED: Perfusion and Vitality of the Femoral Head after Medial Neck Fracture and Osteosynthesis. AIMS: to analyse with regard to necrosis the perfusion and vitality of the femoral head after medial neck fracture and repair by placement of a dynamic hip screw. PATIENTS AND METHODS: Twenty-one patients were examined by scintigraphy immediately following operation as well as at 3 and 6 months postoperative for evaluation of dysfunctions of perfusion and mineralization. RESULTS: Complete perfusion and mineralization defects with a tendency for revascularization at 3 months will be normal at 6 months. Persisting dysfunctions at 3 and 6 months will progress to femoral head necrosis irrespective of the fracture staging. CONCLUSIONS: Three-phase skeletal scintigraphy is a highly sensitive, non-invasive method for evaluating perfusion and revascularization of the femoral head after femoral neck fracture and repair by means of a dynamic hip screw. When perfusion of the femoral head is observed one week after the trauma, femoral head necrosis will not arise. Immobilization is necessary after partial or complete perfusion and mineralization dysfunctions until the scintigraphic findings return to normal. The present results may serve as a recommendation for loading after fracture repair with a dynamic hip screw.

PET imaging of recurrent medullary thyroid cancer.

Medullary carcinoma of the thyroid gland is a rare tumor. Its prognosis is mainly linked to surgery, because there is no valid alternative therapy to improve patients outcome. In this report, we discuss the recurrence of such a tumor in a 64-year-old female, focusing on magnetic resonance imaging and position emission tomography evaluation of this tumor.

[Coincidence of unifocal thyroid autonomy and follicular carcinoma. Case report]. / Koinzidenz von unifokaler Schilddrüsenautonomie und follikulärem Karzinom. Kasuistischer Beitrag.

The case is reported of a 53-year-old man with differentiated thyroid carcinoma within a hot nodule and typical scintigraphic findings of a unifocal adenoma. Preoperative cytology revealed no malignancy. The preliminary histological diagnosis after hemithyroidectomy on the right side was follicular adenoma. The final histological evaluation, however, revealed follicular carcinoma of the thyroid gland. As a result, a thyroidectomy was performed with postoperative radioiodine treatment. The combination of thyroid carcinoma and hot nodules is extremely rare. In all cases of rapid growing nodules or other abnormalities of the thyroid cytological and/or histological verification is mandatory.

[Ileus of the small intestine as sequela of intraduodenal diverticulum. Contribution of roentgen diagnosis to pathophysiology of diverticulum formation]. / Dünndarmileus als Folge eines intraduodenalen Divertikels. Beitrag der Röntgendiagnostik zur Pathophysiologie der Divertikelentstehung.

The case of a 31-year-old male is reported who had recurrent, unexplained abdominal complaints. After hospitalization, an ileus was localized by plain abdominal film in the ileocecal region. A contrast meal revealed a typical intraluminal (duodenal) diverticulum with an enlarged prestenotic duodenum that was undetected during endoscopy. At operation, the cause of the ileus was revealed to be a phytobezoar near the ileocolic valve. After removal and after transluminal resection of the diverticulum, the postoperative course was uneventful. The authors discuss the importance of early roentgen cinematography to clear up the pathogenesis of this very rare intraluminal lesion.