Duplex sonography of the mesenteric vessels--a critical evaluation of inter-observer variability.

INTRODUCTION: The number of publications concerning mesenteric Doppler sonography (mesDS) is immense and does not correlate with the frequency of its use in clinical practice. This is astonishing since it provides real time blood flow (perfusion) information without side effects. Despite uncontrollable parameters like the technical limitations in some situations the optimization of (possibly) controllable parameters like standardization, production of normal values and reduction of the investigator variability by evaluating stable parameters could change the situation. PATIENTS AND METHODS: 10 investigators experienced in abdominal sonography ("DEGUM-Seminarleiter") performed mesenteric Doppler sonography in 5 healthy subjects with 5 different machines. RESULTS: The portal vein at the confluence and the common hepatic artery provide a significant portion of investigations with intromission angles of more than 60°. Values of diameter, resistance index and pulsatility index of the celiac trunc could be obtained with inter-observer variability values below 25 %. The proper and the common hepatic artery show no differences in inter-observer variability values, whereas the intrahepatic measure point of the portal vein showed a higher reproducibility. DISCUSSION: We define frame conditions for future mesenteric Doppler studies: the portal vein should be investigated at the intrahepatic measure point. Pathophysiological studies should refrain from velocity parameters except in the case of larger vessels running in a straight course towards the probe.

[Radiofrequency ablation for treatment of colorectal liver metastases: scientific evidence and clinical reality]. / Die Radiofrequenzablation in der Behandlung von kolorektalen Lebermetastasen: Was ist belegt?

Radiofrequency ablation (RFA) of colorectal liver metastases is frequently reported, but, however, lacks clear criteria for indication and reliable, convincing results with 5-year survival ranging from 17 to 48 %. RFA may be the appropriate treatment modality in approximately 3 to 5 % of all patients suffering from colorectal liver metastases. To date, RFA seems to be limited to no more than three metastases, each smaller than 3 cm. The main indication remains irresectability due to number, site, distribution and/or marginal liver function. Tumours in the vicinity of larger vessels (predominantly branches of portal or hepatic veins) are a case for controversy, since advances in hepatobiliary surgery enable a proportion of patients to undergo resections which would have been declared irresectable until most recently, and the oncological value of a thermoablation is questioned, as a certain amount of temperature is lost due to convective heat sinks. RFA is not a curative alternative to hepatic resection unless small tumours appear during open or laparoscopic procedures in a patient with elevated risk for early recurrence or postoperative morbidity following liver resection. The inclusion of RFA into a holistic system of oncological therapy is mandatory. Early RFA followed by systemic (regional?) chemotherapy can rather be recommended than chemo only, RFA only or first-line chemo with subsequent RFA.

[Hemodialysis fistulas: possibilities of vascular ultrasound]. / Dialyseshunt : Möglichkeiten der Gefässsonographie.

Vascular ultrasound is an established technique in shunt diagnostics for hemodialysis fistulas that allows non-invasive diagnosis of vascular morphology and hemodynamics. Early detection of shunt stenoses in hemodialysis fistulas or thrombotic occlusions facilitates an interventional decision. High occlusion rates of up to 45% within 1 year in hemodialysis fistulas due to reduced flow volume justify follow up with vascular ultrasound examination. The use of high resolution transducers in vascular ultrasound enables complications, such as stenoses and occlusions to be recognized early therefore allowing preemptive therapy. In the present review the examination technique and strategy, the most important complications and treatment options will be discussed.

Contrast harmonic ultrasound and indocyanine-green fluorescence video angiography for evaluation of dermal and subdermal microcirculation in free parascapular flaps.

PURPOSE: Contrast harmonic ultrasound (CHI) with a linear transducer is a new diagnostic approach that allows dynamic and quantitative flow detection of tissue perfusion in microsurgery. The aim of the study was the evaluation of perfusion of the dermal and subdermal layers of microvascular tissue transplants with CHI in comparison to ICG-fluorescence angiography. MATERIAL AND METHOD: In a prospective clinical study Indocyanine-Green Fluorescence Video Angiography and Contrast Enhanced High Resolution Ultrasound (5-10 MHz; linear transducer; Logiq 9; GE) were used for evaluation of the microcirculation in 10 transplanted free parascapular flaps. Two regions were analysed, the centre of the flap and the region of the anastomosis. The perfusion patterns of both methods were compared. RESULTS: The perfusion indexes measured by ICG-fluorescence angiography correlated very precisely in all patients with the quantitative perfusion curves of contrast-enhanced US with CHI. Two flaps with slow filling and low dye intensity showed low contrast enhancement in CHI with modified perfusion curves with slow increase. In two cases a reduced perfusion and filling were found. There were no statistical differences between the two diagnostic methods (p>0.01). CONCLUSION: CHI improves US detections of dermal and subdermal microcirculation in comparison to ICG fluorescence angiography. CHI is a new diagnostic method for postoperative monitoring of free flaps.

Contrast harmonic ultrasound and indocyanine-green fluorescence video angiography for evaluation of dermal and subdermal microcirculation in free parascapular flaps.

PURPOSE: Contrast harmonic ultrasound (CHI) with a linear transducer is a new diagnostic approach that allows dynamic and quantitative flow detection of tissue perfusion in microsurgery. The aim of the study was the evaluation of perfusion of the dermal and subdermal layers of microvascular tissue transplants with CHI in comparison to ICG-fluorescence angiography. MATERIAL AND METHOD: In a prospective clinical study indocyanine-green fluorescence video angiography and contrast enhanced high resolution ultrasound (5-10 MHz; linear transducer; Logiq 9; GE) were used for evaluation of the microcirculation in 10 transplanted free parascapular flaps. Two regions were analysed, the centre of the flap and the region of the anastomosis. The perfusion patterns of both methods were compared. RESULTS: The perfusion indexes measured by ICG-fluorescence angiography correlated very precisely in all patients with the quantitative perfusion curves of contrast-enhanced US with CHI. Two flaps with slow filling and low dye intensity showed low contrast enhancement in CHI with modified perfusion curves with slow increase. In two cases a reduced perfusion and filling were found. There were no statistical differences between the two diagnostic methods (p>0.01). CONCLUSION: CHI improves US detections of dermal and subdermal microcirculation in comparison to ICG fluorescence angiography. CHI is a new diagnostic method for postoperative monitoring of free flaps.

Evaluation of quantitative contrast harmonic imaging to assess malignancy of liver tumors: a prospective controlled two-center study.

AIM: To establish the extent to which contrast enhancement with SonoVue in combination with quantitative evaluation of contrast-medium dynamics facilitates the detection of hepatic tumors. METHODS: One hundred patients with histologically confirmed malignant or benign hepatic tumor (maximum size 5 cm) were analyzed. Contrast-enhanced ultrasound (bolus injection 2.5 mL SonoVue) was carried out with intermittent breath-holding technique using a multifrequency transducer (2.5-4 MHz). Native vascularization was analyzed with power Doppler. The contrast-enhanced dynamic ultrasound investigation was carried out with contrast harmonic imaging in true detection mode during the arterial, portal venous and late phases. Mechanical index was set at 0.15. Perfusion analysis was performed by post-processing of the raw data [time intensity curve (TIC) analysis]. The cut-off of the gray value differences between tumor and normal liver tissue was established using Receiver Operating Characteristic (ROC) analysis 64-line multi-slice computed tomography served as reference method in all cases. Magnetic resonance tomography was used additionally in 19 cases. RESULTS: One hundred patients with 59 malignant (43 colon, 5 breast, 2 endocrine metastases, 7 hepatocellular carcinomas and 2 kidney cancers) and 41 benign (15 hemangiomas, 7 focal nodular hyperplasias, 5 complicated cysts, 2 abscesses and 12 circumscribed fatty changes) tumors were included. The late venous phase proved to be the most sensitive for classification of the tumor type. Fifty-eight of the 59 malignant tumors were classified as true positive, and one as false negative. This resulted in a sensitivity of 98.3%. Of the 41 benign tumors, 37 were classified as true negative and 4 as false negative, which corresponds to a specificity of 90.2%. Altogether, 95.0% of the diagnoses were classified as correct on the basis of the histological classification. No investigator-dependency (P = 0.23) was noted. CONCLUSION: The results show the possibility of accurate prediction of malignancy of hepatic tumors with a positive prognostic value of 93.5% using advanced contrast-enhanced ultrasound. Contrast enhancement with SonoVue in combination with quantitative evaluation of contrast-medium dynamics is a valuable tool to discriminate hepatic tumors.

Cervical artery dissection: improved diagnosis by B-Flow ultrasound.

OBJECTIVE: The objective of this study was to evaluate the efficiency of B-Flow ultrasound in diagnosing supraaortic vessel dissections compared with other ultrasound techniques including B scan, Color-Coded Doppler (CCDS) and Power Doppler (PD). MATERIALS AND METHODS: Eighty-eight patients with suspected arterial dissection of the neck vessels were included in this prospective trial. All patients were examined using B scan, Color-Coded Doppler sonography and Power Doppler. After documentation of the diagnoses, the patients were additionally examined by B-Flow ultrasound. Contrast-enhanced magnetic resonance angiography (MRA) was used as reference standard in all cases. RESULTS: Dissections of the carotid artery (n=19) and of the vertebral artery (n=35) were found in 44 patients. B-Flow imaging identified 52 of 54 arterial dissections that were confirmed by MRA. There were no false-positive diagnoses in ultrasound examination. The sensitivity of ultrasound examination using B scan, CCDS and PD in detecting all dissections was 95.9% and 99.1% with additional B-Flow examination. Sensitivity using B-Flow increased from 98.3% to 100% for carotid dissections and from 93.3% to 94.3% for vertebral artery dissections. Due to the lack of overwriting artifacts, B-Flow imaging detected residual flow within the false lumen more precisely. The reduced effect of the ultrasound probe angle facilitated imaging of fissures, membranes and low flow phenomena and improved the identification of low-reflection wall structures. The cine mode of the B-Flow showed undulating membrane movement most clearly. Contrast-enhanced MRA in conjunction with axial T1 and T2 weighted sequences enabled the best visualization of intramural hematomas. CONCLUSION: B-Flow imaging can significantly increase the sensitivity of ultrasound examination for dissections of the neck vessels. It also improves the visualization of flow within the true and false lumen, of hypoechoic thrombi and of intramural hematoma.

B-flow and B-flow with 3D and SRI postprocessing before intervention and monitoring after stenting of the internal carotid artery.

OBJECTIVE: To investigate the extent to which B-flow and B-flow with 3D postprocessing and speckle reduction imaging (SRI) have advantages in appraising the morphology of a high-grade stenosis of the internal carotid artery (ICA) for preinterventional planning and for postinterventional ultrasonographic follow-up. MATERIALS/METHODS: A comparative appraisal of flow with CCDS, power Doppler, B-flow and 3D B-Flow with SRI were carried out prospectively in 50 patients with >70% stenosis according to NASCET criteria in contrast medium-enhanced MRA before and after the intervention. After stenting of the internal carotid artery (ICA), i.a. digital substraction angiography (DSA) served as an additional reference method. RESULTS: In >70% ICA stenosis, simultaneous imaging of the pre-stenotic, intra-stenotic and post-stenotic flow was attained with B-flow in 45/90 cases (90%), with power Doppler in 39/50 cases (78%) and with CCDS in only 31/50 cases (62%). After intervention, a complete detection of flow without overwriting or blooming artifacts was achieved in all 50 patients only by B-flow. The intrastenotic flow (p<0.05) could be better demarcated against the lumen and the vessel wall before the intervention, whereas the flow within the stent could be very much better appraised after the intervention (p<0.01) using 3D postprocessing of B-flow with additional SRI. Re-stenoses with hypoechoic vascular wall changes (3/50 patients) were detected at an early stage using B-flow. CONCLUSIONS: B-flow technique with SRI and 3D postprocessing can facilitate the intrastenotic detection of flow in >70% ICA stenosis with fewer flow artifacts. After stenting, the perfused vascular lumen shows less flow artifacts compared with CCDS and power Doppler. In order to elucidate hemodynamic changes, additional Doppler examinations are still necessary.

Value of high resolution ultrasound and contrast enhanced US pulse inversion imaging for the evaluation of the vascular integrity of free-flap grafts.

OBJECTIVE: The aim of this study was to evaluate the clinical value of color coded Doppler sonography (CCDS) and contrast-enhanced harmonic imaging (CHI) for ultrasound (US) monitoring the integrity of free-flap vascular grafts. Patency of microvascular anastomoses and perfusion as well as microcirculation of the transplanted tissue were analysed. PATIENTS AND METHODS: Fifteen free parascapular flap grafts performed over a period of three years by a single surgeon were examined with CCDS and CHI. The patients (12 male, 3 female) ranged in age from 16 to 60 years (average age 40+/-12). The follow-up period ranged from two weeks to 2.5 years. CCDS were performed with a multifrequency linear transducer (5-10 MHz, Logiq 9, GE) with 3D flow detection. For detection and characterization, B scan of the flap tissue was compared to tissue harmonic imaging (THI) and Cross Beam with Speckle Reduction Imaging (SRI). US Pulse Inversion Harmonic Imaging (PIHI) after bolus injection of 2.5 ml Sonovue was used for contrast enhancement. RESULTS: Border and tissue structure of the flaps could be detected best in all 15/15 cases using Cross Beam Technology with SRI and THI. Correlations were found for flow parameters of the common femoral artery, popliteal artery and lower leg artery to the anastomotic vessels. 3D imaging with CCDS facilitated flow detection of elongated and small anastomotic vessels in 4/15 cases. Contrast-enhanced US with PIHI allowed dynamic flow detection of the microcirculation of the transplanted tissue over a depth of up to 3 cm with quantitative perfusion curves of the tissue microcirculation. Reduced US contrast enhancement with modified perfusion curves was seen in 2/15 cases with low anastomic flow in CCDS. CONCLUSION: Assessment of microvascular perfusion with contrast-enhanced ultrasound can provide valuable information on free flap viability. Contrast-enhanced US enables dynamic and quantitative flow detection of free flap tissue.

[Digital ultrasonic diagnosis of lower leg venous thrombosis using harmonic imaging and cross beam technology]. / Digitale Ultraschalldiagnostik der Unterschenkelvenenthrombose mit Harmonic Imaging und Cross-Beam-Technik.

PURPOSE: To evaluate the extent to which Tissue Harmonic Imaging (THI) and spatial averaging (Sono-CT, Cross Beam) facilitate the diagnosis of lower leg venous thrombosis. MATERIALS AND METHODS: In 100 cases of lower leg venous thrombosis, the conventional B-scan, THI, and ultrasonic CT technology (Cross Beam) in examinations using a multi-frequency transducer head (9 - 14 MHz, Logiq 9, GE) were compared during follow-up studies using compression sonography over at least 6 weeks. Two independent examiners performed digital image documentation (PACS connection) without modifying the gray level parameters optimized in the B-scan. A thrombosis was considered to be proven sonographically if at least one ultrasonic modality yielded findings reproducible in follow-up checks at a comparable site in accordance with both examiners. RESULTS: Thromboses in the V. tibialis posterior category (97 %) and the fibular category (81 %) were found most often, followed by muscular venous thromboses (48 %). Thromboses in the V. tibialis anterior category were rare (12 %). The procedure comparison showed an advantage for ultrasonic CT technology in terms of the demarcation of thromboses of the deeper veins (sensitivity 98 %), as compared to THI (sensitivity 87 %, specificity 91 %, PPV: 99 %) and the B-scan (sensitivity 81 %). CONCLUSION: If a high-resolution linear transducer is used, THI and ultrasonic CT-Technology can facilitate the diagnosis of a lower leg venous thrombosis.

Vascularization of liver tumors - preliminary results with Coded Harmonic Angio (CHA), phase inversion imaging, 3D power Doppler and contrast medium-enhanced B-flow with second generation contrast agent (Optison).

PURPOSE: To investigate the dynamic value of contrast medium-enhanced ultrasonography with Optison for appraisal of the vascularization of hepatic tumors using harmonic imaging, 3D-/power Doppler and B-flow. MATERIALS/METHODS: 60 patients with a mean age of 56 years (range 35-76 years) with 93 liver tumors, including histopathologically proven hepatocellular carcinoma (HCC) [15 cases with 20 lesions], liver metastases of colorectal tumors [17 cases with 33 lesions], metastases of breast cancer [10 cases with 21 lesions] and hemangiomas [10 cases with 19 lesions] were prospectively investigated by means of multislice CT as well as native and contrast medium-enhanced ultrasound using a multifrequency transducer (2.5-4 MHz, Logig 9, GE). B scan was performed with additional color and power Doppler, followed by a bolus injection of 0.5 ml Optison. Tumor vascularization was evaluated with coded harmonic angio (CHA), pulse inversion imaging with power Doppler, 3D power Doppler and in the late phase (>5 min) with B-flow. In 15 cases with HCC, i.a. DSA was performed in addition. The results were also correlated with MRT and histological findings. RESULTS: Compared to spiral-CT/MRT, only 72/93 (77%) of the lesions could be detected in the B scan, 75/93 (81%) with CHA and 93/93 (100%) in the pulse inversion mode. Tumor vascularization was detectable in 43/93 (46%) of lesions with native power Doppler, in 75/93 (81%) of lesions after administering contrast medium in the CHA mode, in 81/93 (87%) of lesions in the pulse inversion mode with power Doppler and in 77/93 (83%) of lesions with contrast-enhanced B-flow. Early arterial and capillary perfusion was best detected with CHA, particularly in 20/20 (100%) of the HCC lesions, allowing a 3D reconstruction. 3D power Doppler was especially useful in investigating the tumor margins. Up to 20 min after contrast medium injection, B-flow was capable of detecting increased metastatic tumor vascularization in 42/54 (78%) of cases and intratumoral perfusion in 17/20 (85%) of HCC cases. All 19 hemangiomas were correctly classified by phase inversion imaging. CONCLUSIONS: Contrast medium-enhanced ultrasound investigation of liver tumors with Optison allowed reliable detection of tumor foci and, in most cases, appraisal of tumor vascularization. The time available for evaluation of tumor margin vascularization was substantially longer in B-flow.

Rapid course radiation therapy vs. more standard treatment: a randomized trial for bone metastases.

PURPOSE: In a prospective randomized trial we examined whether radiotherapy of painful bone metastases can be shortened using larger single doses without impairing effectivity. METHODS AND MATERIALS: One hundred patients with painful bone metastases having no prior surgical intervention or treatment with x-ray therapy and had a median follow-up of 12 months were analyzed. The primary tumor was located in the breast in 43%, in the lung in 24%, and in the prostate in 14%. The most frequent sites of metastases were the pelvis (31%), the vertebral column (30%), and the ribs (20%). Further percentages of sites were: lower extremity 11%, upper extremity 6%, and skull 2%. Fifty-one patients received a short course radiotherapy with a total dose of 20 Gy in 1 week (daily dose 4 Gy), and 49 patients received 30 Gy in 3 weeks (daily dose 2 Gy). RESULTS: There were no significant differences in frequency, duration of pain relief, improvement of mobility, recalcification, frequency of pathologic fractures nor survival. There was a light trend favoring 30 Gy in frequency of pain relief and recalcification. Survival was mostly influenced by primary tumor site, Karnofsky performance status, and possibly by the response to radiotherapy (pain relief). CONCLUSIONS: Because of the very short life expectancy of patients with metastatic bone disease, we now use 20 Gy in 1 week as our standard to reduce hospital stay.

Noninvasive method for measuring thrombus formation in patients after peripheral angioplasty using three-dimensional B-mode and color-coded Doppler ultrasonography.

Clinical investigations studying the effect of newer medications on such complex pathophysiology as the formation of an arterial or venous mural thrombus have been limited to clinical symptomatic endpoints. Biochemical markers so far have not been convincing in quantifying ongoing thrombus formation. Consequently, clinical development of new antithrombotic compounds has had to rely on clinical symptoms that occur either comparably late in the course of the disease and may therefore be influenced by many other factors, or on those symptoms that occur at a relatively low incidence rate. Both circumstances make studies for dose-finding and determination of optimal drug regimens more difficult and time consuming. Using conventional clinical noninvasive ultrasonography, the volume and geometry of a peripheral arterial segment can be measured with high sensitivity and reproducibility in healthy volunteers (% coefficient of variation = 8.01%). In patients, thrombus volume was monitored after peripheral transluminal angioplasty of the femoral artery. All patients received a standard anticoagulant treatment with heparin for 24 hours after the procedure. Volume measurements were performed at 20, 29, 44, 53, and 68 hours after angioplasty. When compared with the obstruction volume at 20 hours, a slight increase could be detected at 29, 44, and 53 hours. At 68 hours there was a significant increase in obstruction volume. This indicates that volume measurements may detect changes in the course of thrombus formation, related to the antithrombotic treatment regimen, at a level at which clinical symptoms may not be present.

A study of dose reduction using digital luminescence radiography for lateral skull radiography.

For lateral skull radiography the minimum required radiation patient exposure to ensure adequate image quality was determined for digital luminescence radiography (DLR) in comparison with a screen-film system (speed class 200). Radiographs were produced with a grid technique on conventional X-ray equipment. A real prepared female head including a true fracture above the pars petrosa ossis temporalis was imaged. The tube current-time product (mAs), and thus the surface entrance dose, was varied systematically. Surface entrance dose was measured with TLD-100 rods. Image quality was judged by experienced radiologists according to the criteria: visual resolution, mean optical density, contrast and perceptibility of specific bone structures. Surface entrance dose was reduced from 0.46 to 0.20 mGy by application of DLR instead of speed class 200 screen-film system without loss of diagnostic information in clinical routine. This corresponds to a dose reduction potential of 57% showing a good agreement with the dose reduction potential of 52% obtained in a previous study using the Alderson head phantom.

[Experiences with the endovascular embolization therapy of aneurysms of the splanchnic arteries--a report on 13 cases]. / Erfahrungen mit der endovaskulären Embolisationstherapie von Aneurysmata der Splanchnikusarterien--Bericht über 13 Fälle.

PURPOSE: The authors report on their experience in endovascular embolization therapy in 13 cases with splanchnic artery aneurysms or pseudoaneurysms. PATIENTS AND METHODS: Three patients suffered from true aneurysms, ten patients presented pseudoaneurysms of different origin. Eight patients were transferred to our department for life-threatening intestinal bleeding. Five patients showed transpapillary bleeding, four of whom presented with haemobilia and one patient had intermittent bleeding into the pancreatic duct due to a true aneurysm of the splenic artery. Embolization was performed using a coaxial microcatheter coil delivery system. In 4 patients the aneurysm-bearing vessel was temporarily blocked during the intervention. RESULTS: In 11 patients definite occlusion of the aneurysm was obtained without surgical intervention. In one patient, suffering from a splenic aneurysm, we observed a partial inadvertent embolisation of the spleen which did not require further treatment. In one case, rupture of an hepatic aneurysm during embolization occurred. One patient with pseudoaneurysm due to displacement of a port catheter showed severe rebleeding one day after embolisation. CONCLUSION: Transcatheter embolization is an effective method for treatment of aneurysms of the splanchnic arteries. To avoid life-threatening bleeding due to rupture of the aneurysm, the feeding vessel should be temporarily blocked during embolization therapy.

[Noninvasive diagnosis of splenic artery aneurysm]. / Nicht-invasive Diagnostik von Milzarterienaneurysmata.

The findings and problems of differential diagnosis of splenic artery aneurysms are illustrated by three patients. By a combination of Doppler sonography and conventional duplex sonography, it was possible to achieve a correct and non-invasive diagnosis.

[Improved evaluation of stenoses of hemodialysis fistulas by B-flow ultrasound]. / B-Flow zur verbesserten sonographischen Beurteilung von Dialyse-Shunt-Stenosen.

PURPOSE: To evaluate the new technique of B-flow ultrasound in assessing stenoses of hemodialysis fistulas. MATERIALS AND METHODS: 50 patients (mean age 58 years) with Brescia-Cimino-Shunts (27 shunts of the radial and 23 of the cubital artery) were prospectively assessed with intraarterial DSA and vascular ultrasound by independent examiners. Eligibility for the study was a shunt-volume of less than 400 ml/min and an angiographically suspected hemodynamically significant stenosis of the anastomosis or of shunt veins. Sonography was performed with a multifrequency ultrasound probe (5 to 10 MHz, Logic 700, GE) using B-mode, color coded Doppler sonography (CCDS) and B-flow technique. RESULTS: Anastomotic stenosis and stenosis of the shunt veins were equally distributed, found in 25 patients each. The measurements of the residual lumen of the 25 anastomotic stenoses were 1.47 to 3.43 mm (average: 2.3 mm) for intraarterial DSA, 1.57 to 3.73 mm (average: 2.6 mm) for B-mode ultrasound, 1.97 to 4.17 mm (average: 2.9 mm) for CCDS, 1.43 to 3.47 mm (average: 2.3 mm) for B-flow technique in the brightness mode and 1.6 to 3.47 mm (average: 2.4 mm) for B-flow technique in the B-mode. The brightness mode of the B-flow correlated best with intraarterial DSA (r=0.994), with a significantly lower correlation between CCDS and intraarterial DSA. B-flow displays less vascular distortion within the stenosis and fewer flow artifacts. Even in angulated stenoses, the detected intra- and poststenotic flow was markedly less angle-dependent in comparison with CCDS. B-flow clearly facilitates the visualization of hypoechoic plaques and intima proliferation. Furthermore, eccentric cicatricial stenoses, intima flaps or hypoechoic thrombi, which were not seen with DSA or B-mode, showed improved visualization in comparison with CCDS. CONCLUSION: Ultrasound B-flow makes it easier to assess the morphology and the local degree of stenotic hemodialysis fistulas. Flow detection is achieved with fewer artifacts and reduced angle dependence. This opens the way for better planning of interventional therapy.

[Quantification of pulmonary alveolar microlithiasis in the CT]. / Quantifizierung der pulmonalen alveolären Mikrolithiasis im CT.

Pulmonary alveolar microlithiasis is a rare, familial disease with massive symmetrical intra-alveolar calcium deposition. Conventional CT findings and CT measurements with a dual energy technique were carried out in a 26-year-old patient suffering from this disease. The importance of the findings in the differential diagnosis and for estimating the progression and prognosis of the disease is discussed.

[B-flow and contrast medium-enhanced power Doppler (Optison(R))--preoperative diagnosis of high-grade stenosis of the internal carotid artery]. / B-Flow und kontrastmittelverstärkter Power Mode mit Optison(R) - Präoperative Diagnostik der hochgradigen Stenose der A. carotis interna.

PURPOSE: To improve sonographic diagnosis of high-grade stenosis of the internal carotid artery (ICA) by vascular sonography in "B-flow"-mode and in contrast medium (Optison(R))-enhanced power Doppler (PD). MATERIAL AND METHODS: 88 patients suspected of a high-grade stenosis of the extracranial ICA were examined by independent examiners with color-coded Doppler (CCD), B-flow and PD to compare the methods for morphology and degree of stenosis. In 21 cases contrast medium was used in PD. Sonographic results of all 88 patients were compared with selective angiography (DSA), in 53 cases with operative findings. RESULTS: A complete occlusion was found in 9 patients and a 50 - 70 % degree non-exulcerated stenosis in 26 cases. 53 of 88 patients presented findings in both sonography and DSA leading to operation of the ICA. Among these 47 had a stenosis > 70 % and 6 a stenosis of 60 - 70 % with exulcerated plaques. Even a small dose of contrast medium (0.3 ml) gave a significant signal increase in PD improving flow detection even in extensive vascular calcification. In both the early phase (up to the first minute p. i.) flow contrast was optimal and without significant artifacts. Thus, the extent and the morphology of the stenosis was better appreciated. Hypoechogenic plaques, ulcerations and thrombi are as easily recognized by B-flow as flow in preocclusive stenosis, free of vibration and blooming artifacts. This gave a better correlation with DSA and a higher diagnostic accuracy in grading a stenosis than CCD and PD. Circular calcifications or vessel kinking made diagnosis of flow more difficult. CONCLUSION: B-flow allows a reliable diagnosis of the degree of stenosis of ICA and a better appreciation of plaque morphology than CCD. In some cases with extensive calcifications contrast medium-enhanced PD is able to detect better intrastenotic flow. Only small quantities of contrast medium (Optison(R)) are required.

[Radiation exposure in abdominal radiography with digital luminescence radiography and conventional screen-film system: an experimental animal study]. / Die Strahlenexposition bei der Abdomen-Ubersichtsaufnahme mit digitaler Lumineszenzradiographie und konventionellem Film-Folien-System--eine tierexperimentelle Untersuchung.

PURPOSE: To determine and compare the minimum required radiation exposure for a.-p. abdominal radiographs with digital luminescence radiography (DLR) and a screen-film system (SFS) providing adequate image quality in clinical routine. MATERIAL AND METHOD: Abdominal radiographs a.-p. of a pig were produced with DLR and SFS systematically varying the tube current-time product. The image quality was assessed by eight experienced radiologists according to the criteria of visual resolution, mean optical density, perceptibility of the lateral edge of the psoas, the caudal edge of the liver, bone structures and intestinal wall. RESULTS: The image quality of the digital radiographs was better for each criterion except visual resolution if the same current-time product was used for both techniques. From the minimum tube current-time products providing an adequate image quality it follows that a dose reduction of 57% can be achieved by applying DLR instead of speed class 200 SFS. CONCLUSION: The recently published guide-lines for quality assurance in x-ray diagnostics issued by the German Federal Board of Physicians recommend using speed class 400 SFS. Since in that case an approximately halved radiation dose is necessary, dose reduction is hardly to be expected with DLR.