[Measurement precision of sonography to evaluate movable meniscal bearings]. / Die Messgenauigkeit der Sonographie zur Evaluierung beweglicher Meniskallager.

After resection of the ACL, the knee exhibits a paradoxical movement but the effect of this movement on function,wear, and implant survival in a meniscal bearing total knee replacement (TKR) is not known. Up to now, only radiological methods are described to measure the meniscal bearing's movement. We developed a method using ultrasound for analyzing MB motion. In an in vitro study we compared ultrasound of 5 MHz with 8 and 12 MHz, we studied the effect of malrotation on the projection of plain and digital radiographs, and compared ultrasound of 8 MHz with plain and digital radiographs. In all three methods the distance was measured between the anterior border of the tibial component and the anterior rim of the meniscal bearing. The accuracy and precision of 8 and 12 MHz were identical and statistically significantly more accurate than 5 MHz (p<0.01). Malrotation had a significant impact on the radiological projection. Neutral rotated radiographs and ultrasound of 8 MHz did not differ in accuracy and precision, but ultrasound was significantly more accurate than any radiograph with a malrotation of 1 degrees or more (p<0.001). We conclude that ultrasound of 8 MHz is an alternative to radiological methods for the measurement of meniscal bearings' motion.

[The value of different spiral CT phases in the detection of liver metastases]. / Der Wert unterschiedlicher Spiral-CT-Phasen in der Suche nach Lebermetastasen.

PURPOSE: To assess the value of the non-contrast phase (NCP), hepatic-arterial phase (HAP) and portal-venous phases (PVP) for the detection of liver metastases by spiral CT. METHODS: In order to detect liver metastases, 119 patients (58 women, 61 men; mean age: 62 years) underwent triphasic spiral CT (8 mm collimation, 12 mm table increment/rotation, 7 mm reconstruction increment). NCP, HAP (20 s delay) and PVP (70 s delay) scans were acquired (contrast medium injection rate: 4 ml/s). CT analysis comprised independent evaluation of the three scan series for detection and conspicuity of liver metastases (conspicuity score: 0 = not visible, 1 = barely visible, 2 = clearly visible, 3 = distinctly visible). RESULTS: In 83 of the 119 patients, 478 liver metastases were detected (110 hypervascular and 368 hypovascular lesions). 285 (60 %) metastases were detected on NCP scans. Significantly more lesions were seen on HAP (n = 375, 78 %) and on PVP (n = 428, 90 %). No lesion was detected on NCP studies alone. For all detected metastases, mean conspicuity was 1.2 +/- 0.4 on NCP, 1.8 +/- 0.8 on HAP and 2.2 +/- 0.8 PVP. Hypervascular lesions were best seen on HAP with a conspicuity score of 2.0 +/- 0.8 versus 1.3 +/- 0.5 on NCP and 1.5 +/- 0.8 on PVP. Hypovascular lesions reached the highest conspicuity on PVP with 2.4 +/- 0.8 versus 1.2 +/- 0.4 on NCP and 1.7 +/- 0.7 on HAP. CONCLUSION: For detection of liver metastases with spiral CT, contrast series seem to be sufficient. For tumors likely to seed hypervascular metastases, HAP scans should be applied in addition to the PVP.

[Acute appendicitis in non-contrast spiral CT: a diagnostic luxury or benefit?]. / Akute Appendizitis im Nicht-Kontrast-Spiral-CT: diagnostischer Luxus oder Nutzen?

PURPOSE: To evaluate the diagnostic accuracy of thin collimated unenhanced spiral-CT in patients with clinically suspected acute appendicitis and to determine the impact on patient management and overall costs. METHOD: Unenhanced focussed appendiceal spiral-CT was performed in 56 patients (23 women and 33 men) with clinically suspected acute appendicitis. Scans were obtained from the L4 level to the symphysis pubis using 5 mm collimation, 7.5 mm table feed (pitch 1.5) and 4 mm increment without i.v., oral, or rectal contrast material. Prospective diagnoses based on CT findings were compared with surgical (and histopathological) results and clinical follow-up. The effect of spiral-CT on patient management and clinical resources was assessed. RESULTS: 29 patients (10 women and 19 men) underwent appendectomy. Unenhanced spiral-CT was an accurate imaging technique for the initial examination of patients with suspected acute appendicitis with a sensitivity of 95.4% and a specificity 100%, an accuracy of 98.2%, a positive predictive value of 100%, and a negative predictive value of 97.1%. In 27 patients with no evidence of acute appendicitis, an alternative diagnosis could be made in 24 patients by unenhanced spiral-CT. CONCLUSION: Unenhanced spiral-CT is an accurate test to diagnose or to exclude acute appendicitis. Routine appendiceal spiral-CT can improve medical care and reduce the overall costs for patients suspected of having acute appendicitis.

[Native spiral computerized tomography in patients with acute flank pain--sense or nonsense?]. / Nativ-Spiral-Computertomographie bei Patienten mit akutem Flankenschmerz--Sinn oder Unsinn?

PURPOSE: To compare the diagnostic efficacy and costs of native spiral-CT and intravenous urography (IVU) in the management of patients with acute flank pain. METHOD: Native spiral-CT and IVU (following about 30 minutes after CT) were compared in 66 patients with acute flank pain followed by an IVU. The spiral-CT protocol was: 5-mm section thickness, 7.5-mm table feed and 3-mm increment. The analysis conducted independently by two radiologists entailed: (a) Morphology: presence of stone disease (yes-no), localization and size of calculi, periureteral and perirenal stranding, dilatation of the collecting system, and possible alternative diagnoses and (b) cost-effectiveness: direct and indirect costs. RESULTS: Fifty-two patients had urolithiasis. The detection rate of renal and ureteric calculi was significantly higher with native spiral-CT than with IVU (100% vs. 69%, respectively) (p < 0.05). A specific sign of ureteric calculi was the so-called soft tissue "rim sign" (sensitivity 82% and specificity 100%, respectively). In 13 of 14 patients with acute flank pain with no evidence of urolithiasis alternative diagnoses could be made by spiral-CT. Spiral-CT was significantly more cost-effective than IVU in management. CONCLUSION: Native spiral-CT is faster, more effective and less expensive than IVU in the management of patients with acute flank pain. Additionally, it poses less risk and has the capability for allowing alternative diagnoses. Therefore, unenhanced spiral-CT should be the first line modality in patients with acute flank pain.

Anterior and upward displacement of the inferior mesenteric vein:a new diagnostic clue to left paraduodenal hernias?

A 26-year-old man with acute deterioration of recurrent abdominal pain was admitted to the hospital. Plain film (abdominal radiographs), spiral computed tomography (CT), and barium contrast studies were performed. A left paraduodenal hernia causing acute jejunal obstruction was identified on upper gastrointestinal barium studies and spiral CT. Pre- and postsurgery examinations were compared, and relevant radiological findings were identified. Spiral CT provided excellent visualization of the pathognomonic displacement of the inferior mesenteric vein.

Mucinous biliary cystadenocarcinoma containing gas bubbles secondary to duodenal invasion.

Biliary cystadenocarcinoma is a rare, usually intrahepatic neoplasm. A case is described in which an intrahepatic cystadenocarcinoma invaded the duodenum. This resulted in intratumoral gas.

Sonographic evaluation of focal nodular hyperplasias (FNH) of the liver with a transpulmonary galactose-based contrast agent (Levovist).

Focal nodular hyperplasias (FNH) are hypervascular, benign focal liver lesions. Differentiation of FNH from other focal liver lesions is of clinical importance. The purpose of this study was to examine the impact of a new, transpulmonary echo-enhancing agent SHU 508A (Levovist) and recent Doppler techniques in the sonographic evaluation of FNH. 43 patients with 61 focal nodular hyperplasias of the liver were examined with grey scale ultrasound and power Doppler ultrasound. Levovist, a galactose-air-microbubble suspension was administered intravenously in all patients, either by bolus injection (400 mg ml-1) or continuous pump-infusion (300 mg ml-1). Visualization of the feeding vessels and vascularity of the lesions were evaluated. The resistance indexes (RI) in the feeding vessel and the hepatic artery were assessed and compared with the diameters of the FNH. The mean diameter of FNH was 4.3 cm (+/- 1.0). Echo enhanced power Doppler ultrasound was superior to unenhanced power Doppler ultrasound in the detection of the feeding artery (85% vs. 98%) in FNH and depicted the internal vascular architecture more clearly, especially in lesions located in the left lobe of the liver. Lesions smaller than 3 cm did not show a characteristic vascular architecture with echo enhanced Doppler ultrasound. The resistance index of the feeding artery (mean: 0.51 +/- 0.08) is significantly (p < 0.0001) lower than that of the hepatic artery (mean 0.65 +/- 0.06) with a mean difference of -0.14 +/- 0.01 in the same patient. The RI of the feeding artery significantly decreased as the size of the FNH increased, whereas RI differences between the hepatic artery and the feeding artery increased with lesion size. Intravenous (i.v.) bolus injection of the contrast agent will depict the hypervascular nature of FNH more clearly than i.v. infusion, although the latter will significantly prolong the diagnostic window. In conclusion, i.v. infusion of Levovist improves the visualization of the feeding artery and the radiating vascular architecture in FNH located in the left lobe of the liver due to improved signal-to-noise ratio and results in more effective suppression of motion artefacts. Although echo enhanced Doppler ultrasound improves the detection of the low resistance arterial feeding vessel in small FNH, it will not, however, reveal a specific vascular pattern in these lesions.

[Dissecting aneurysm of an aberrant right subclavian artery: diagnosis with ultrafast-CT]. / Disseziierendes Aneurysma einer aberranten Arteria subclavia dextra: Diagnose mittels Ultrafast-CT.

An aneurysm of an aberrant right subclavian artery is a very rare cause for dysphagia. We describe such a case in a 67-year-old patient, diagnosed with Ultrafast-CT and discuss it together in concert with the embryology and the radiological findings.