[Transjugular intrahepatic portosystemic shunt in patients with portal vein thrombosis]. / Transjugulärer intrahepatischer portosystemischer Shunt bei Patienten mit Pfortaderthrombose.

PURPOSE: To evaluate the feasibility of TIPS for portal vein thrombosis (PVT) with/without portal vein occlusion/cavernomatous transformation and with/without underlying cirrhosis. MATERIALS AND METHODS: 13 patients with PVT and refractory ascites (n=7) and variceal bleeding (n = 6) received TIPS placement. The function of the TIPS was controlled with Doppler US at 1 day, 1 week, 4 weeks and 4 months after TIPS placement and subsequently every 3 months. The rates of technical success, revision and mortality after TIPS were evaluated. RESULTS: The TIPS was successfully placed in 85% (11/13) of the cases. TIPS placement was successful in 87.5% (7/8) of patients with occlusion of the right portal vein and in 100% (5/5) of patients with non-occlusive right portal vein (p > 0.05), in 80% (8/10) of cirrhotic (x/10) and in 100% (3/3) of non-cirrhotic patients (p > 0,05), as well as in one patient with a fresh PVT and in 1 of 2 patients with cavernous transformation. 30 and 14.3% of patients needed a TIPS revision in the first and second year, respectively. No patient with occlusion of the right portal vein required a revision. 54.5% (6/11) of patients died within 6 months. Under exclusion of 4 patients with advanced malignant diseases, the mortality rate was 28.6%. CONCLUSION: TIPS should be considered for selected patients with symptomatic occlusive PVT with/without cavernous transformation and with/without underlying cirrhosis. The frequency of TIPS revision is not greater, and the mortality rate 6 months after PVT recanalization seems to be comparable with that of patients without PVT.

[Diagnostic value of multislice perfusion CT in dementia patients]. / Bedeutung der zerebralen Perfusionsmessung am Mehrzeilenspiral-CT in der Demenzdiagnostik.

BACKGROUND: The diagnostic value of perfusion CT in dementia patients was retrospectively evaluated in comparison to the Mini-Mental State Examination (MMSE). MATERIAL AND METHODS: The perfusion CT database of 55 subjects was investigated. All patients underwent an unenhanced, contrast-enhanced, and perfusion CT of the head. The clinical evaluation of the degree of dementia was performed with the MMSE. In the perfusion CT data, 24 ROI were marked. Then blood volume (BV), blood flow (BF), and mean transit time (MTT) were calculated and compared with the ipsilateral and contralateral regions and with the degree of dementia. RESULTS: With increasing degree of dementia, a significant decrease of the occipital and temporal BV was found. A significant decrease of the BF in the frontal lobe, basal ganglia, and occipital region was found. Concurrently, the MTT increased significantly in the basal ganglia region. The group with Alzheimer's disease showed significant regional hypoperfusion compared with the group of cognitively normal subjects in the frontal, basal ganglia, occipital, and temporal region. CONCLUSIONS: The cerebral perfusion decreased with increasing degree of dementia. The inexpensive and widely available perfusion CT reveals information about regional differences of cerebral perfusion, which may be useful in differentiating severity and types of dementia.

Radiation risks for the radiologist performing transjugular intrahepatic portosystemic shunt (TIPS).

The aim of this study is to evaluate the radiation dose to the interventional radiologist in transjugular intrahepatic portosystemic shunt (TIPS) concerning the risk of cancer and deterministic radiation effects and the relation to recommended dose limits. In 18 TIPS interventions radiation doses were measured with thermoluminescence dosemeters (TLD) fixed at the eyebrow, thyroid and hand of the radiologist without special lead shielding of these body parts and at the chest, abdomen and testes under the lead apron. The doses of the eye lens, thyroid gland and hand were assumed to be equal to the corresponding surface doses. The dose at the abdomen under the lead apron was used as an estimation of the ovarian dose. Effective dose equivalent was estimated by Webster's method. The estimated effective dose equivalent was 0.087 mSv and the effective dose 0.110 mSv. The risk of fatal cancer was of 10(-6) and the risk of severe genetic defect of 10(-7) for one single intervention. The maximum permissible number of TIPS interventions was 181, otherwise the dose limit for effective dose would be exceeded. When the radiologist performed more than 372 TIPS procedures per year for many years, the dose to the lens of the eye could exceed the threshold for cataract. If the interventionist performs a large number of TIPS procedures in a year, the risk of fatal cancer and developing cataracts becomes relatively high.

[Radiation dose of the radiologist and the assistant in transarterial hepatic chemoembolization--comparison with the dose limits]. / Die Strahlendosis des Radiologen und des Assistenten bei der transarteriellen hepatischen Chemoembolisation -- Vergleich mit den Dosisgrenzwerten.

PURPOSE: To determine the values of effective dose and partial body dose for the radiologist and the assistant during transarterial chemoembolization (TACE) of hepatocellular carcinoma (HCC) und to compare the doses with the dose limits. MATERIALS AND METHODS: In 65 TACE of HCC cases, values of various surface doses for the radiologist and the assistant were measured. The measurements were performed with the help of thermoluminescence dosemeters (TLD) that were attached to the eyebrows, over the lobes of the thyroid gland, to the breasts, abdomen and symphysis, and to the hands and the lower legs. The measured surface dose values were used as indicators of the exposure of the organs and tissues located near the surface, i. e. eye lens, thyroid gland, breast, testes and tibia. They were also seen as conservative estimations of tissues deep inside the body and the extremities. RESULTS: The highest surface dose for the radiologist was measured at the lower leg (0.58 +/- 0.28 mSv) and the highest surface dose for the assistant was measured at the right lower leg (0.24 +/- 0.20 mSv) since it was closer to the tube than the left side, followed by the dose values at the also unprotected areas of the eyebrows, lobes of the thyroid gland and the hands. The estimated value of the effective dose was 0.06 +/- 0.03 mSv for the radiologist and 0.04 +/- 0.01 mSv for the assistant. With regard to the relationship between the dose limits according to the German X-ray regulation and the measured values and with regard to the maximum possible number of interventions per year, the partial body dose of the red bone marrow in the lower leg provided the greatest limitation, followed by the partial body dose of the muscle in the lower leg and the effective dose. CONCLUSION: In order to meet the dose limits, especially the lower leg should be protected, and the effective dose should also be reduced.

[Diagnostic value of MR analysis of cartilaginous lesions compared with intraoperative arthroscopy in calcaneal fractures]. / Diagnostische Wertigkeit der MR-tomographischen Knorpelläsionsdarstellung im Vergleich mit der intraoperativen Arthroskopie bei Calcaneusfrakturen.

PURPOSE: To determine the diagnostic value of MRI in preoperative analysis and classification of cartilaginous lesions - especially of the posterior facet - in traumatic calcaneal fractures compared with intraoperative arthroscopy. MATERIALS AND METHODS: Twenty-four consecutive patients with traumatic calcaneal fractures underwent prospective MRI of the subtalar joint surface using T1- and T2-weighted spin echo sequences and fat suppressed 3D gradient echo sequences in semicoronal slice orientation (1.5 T MRI). After randomization, the images were analyzed by two blinded and independent readers experienced in MRI. The results were compared with the intraoperative arthroscopic findings as to location and depth of the defects using the Outerbridge classification. RESULTS: We examined 12 calcaneal fractures of type 2, 8 of type 3 and 4 of type 4 according to the Sanders classification. With respect to principal detection and exact classification, 67 of 96 (69.8 %) of all arthroscopic verified cartilaginous defects were diagnosed correctly by MRI. Disregarding the degree of the defects, 38 of 44 (86.4 %) chondral lesions were detected (sensitivity: 86.4 %, specificity: 86.5 %, diagnostic accuracy: 86.5 %). Considering the chondral lesions of degrees 3 and 4 together, the sensitivity was 86.0 %, the specificity 86.8 %, and the diagnostic accuracy 86.5 % . Assessing these degrees separately, the sensitivity was only 33.3 % for degree 3 and 58.1 % for degree 4, whereas the specificity was definitely higher with 82.1 % for degree 3 and 89.2 % for degree 4. CONCLUSION: The MR detection of cartilaginous defects in calcaneal fractures has a sufficient diagnostic accuracy for planning the surgical intervention and assessing the long-term postsurgical prognosis.

Portal vein thrombosis: etiology, diagnostic strategy, therapy and management.

Myeloproliferative disorder, liver cirrhosis with portal hypertension, deficiency of natural anticoagulant proteins, gene mutation and hepatocellular carcinoma are the most frequent causes of portal vein thrombosis (PVT). Higher accuracy of the diagnostic methods is the reason why today the cause of PVT can be found more frequently. With imaging methods, PVT with or without cavernous transformation can be diagnosed. Fresh thrombus can be undetected in sonography due to the low echogenity but can be recognized in color Doppler sonography, especially with contrast-enhancing agent. Contrast-enhanced 3D MR angiography allows a comparable accuracy in the detection of PVT as digital subtraction angiography. Therapeutical options of PVT consist of mechanical recanalization of the portal vein, local fibrinolysis with or without placement of transjugular intrahepatic portosystemic stent shunt (TIPS), combination of mechanical recanalization and local fibrinolysis, systemic thrombolytic therapy, anticoagulation alone and surgical thrombectomy. Once PVT is found in sonography, Doppler sonography may be performed in order to distinguish benign from malignant thrombus. If further information is needed, MR angiography or contrast enhanced CT is the next step. If these tests are unsatisfactory, digital subtraction angiography should be performed. Until the early nineties, shunt surgery was recommended in patients with PVT who bled despite endoscopic treatment. Today, in symptomatic noncavernomatous PVT, recanalization with local methods is recommended. Additional implantation of TIPS should be performed when the patient is cirrhotic. In recent PVT in non-cirrhotic patients anticoagulation alone is recommended. It is expected that in old PVT anticoagulation can prevent further extension of the thrombus.

Assessment of vascularity in reactive lymph nodes by means of D-galactose contrast-enhanced Doppler sonography.

RATIONALE AND OBJECTIVES: A prospective study in signal-enhanced Doppler sonography of lymph nodes that were assumed pretherapeutically to be benign was performed to investigate characteristic sonomorphologic features and vascularity of reactively enlarged lymph nodes. METHODS: Thirty-four patients with enlarged superficial lymph nodes of the neck were examined first by B-scan sonography then by Doppler sonography before and after administration of an ultrasound signal-enhancing agent. In B-scan sonography, lymph nodes were classified into three groups according to their sonomorphologic features: (1) homogeneous parenchyma, (2) a centrally located echogenoic line, and (3) a echogenoic "hilus reflex." In conventional and contrast-enhanced Doppler sonography, peak flow rate, pulsatility index, and resistive index were assessed. Sonomorphologic criteria were compared with histologic findings. RESULTS: Reactively enlarged lymph nodes showed characteristic sonomorphologic patterns correlating to their histologic features. Echogenicity of the hilus corresponded to fibrosis (centrally located echogenoic line in 13 nodes; 38.2%) or fatty involution of the hili (echogenoic hilus reflex in 15 nodes; 44.1%). Administration of the galactose-based ultrasound contrast enhancer facilitated the assessment of hilar vessels, which projected to the echogenoic hili, respectively, actually additionally visualized a hilar vascularity in 10 of the 34 lymph nodes compared with conventional Doppler. Measured Doppler indices gave not a significant clue for identifying reactive lymph nodes or for differential diagnosis. CONCLUSIONS: Qualitative sonomorphologic assessment of characteristic sonomorphologic features of reactive lymph nodes may serve as a valuable tool for examining reactively enlarged lymph nodes. Administration of an ultrasound echo enhancer allows the assessment of a characteristic nodal vascularity in reactive lymph nodes and were superior to conventional B-mode and conventional Doppler sonography.

Radiation exposure in spiral computed tomography. Dose distribution and dose reduction.

RATIONALE AND OBJECTIVES: The authors investigate the dose distribution of spiral and conventional computed tomography (CT) with film densitometry and to present a new method of evaluating the possibility of dose savings with spiral CT. METHODS: Films were exposed in a cuboid polymethyl-methacrylate phantom in conventional and spiral scan technique. Axial density profiles were obtained by digitizing the films using a fluorescent light scanner. The ratio of the number of rotations in spiral CT to the number of slices in conventional CT was calculated. RESULTS: In spiral CT with a pitch of 2, the densities in all points were lower than those in corresponding points in spiral CT with a pitch of 1 and in conventional CT with slice distance equal to slice thickness. A pitch of 1.5 in spiral CT led to a dose reduction of 14% to 30% compared with conventional CT. CONCLUSIONS: Increasing the pitch in spiral CT leads to a reduction of both integral dose and absorbed doses within the examined body region. The reduction of the integral dose can be significant, especially in cases where slice overlapping is diagnostically advantageous.

D-galactose-based signal-enhanced color Doppler sonography of breast tumors and tumorlike lesions.

RATIONALE AND OBJECTIVES: This study sought to evaluate prospectively the diagnostic potential of unenhanced and enhanced color Doppler and power Doppler for the differentiation of tumors and tumorlike lesions of the breast. METHODS: Ninety-two patients with 110 tumors or tumorlike lesions of the breast were investigated by unenhanced and enhanced color and power Doppler ultrasound. The sonomorphologic aspects of vascularization were analyzed. In addition, maximal systolic frequency shift, resistance, and pulsatility indices were determined. RESULTS: In 15 (24%) of 63 primary carcinomas, 15 (68%) of 22 fibroadenomas, and all (100%) of 14 postoperative lesions, the sonomorphologic analysis for the differential diagnosis of breast tumors was improved after contrast enhancement in color Doppler mode. In comparing unenhanced color Doppler to power Doppler, the latter was found to be slightly superior (sensitivity, 60% vs. 67%; specificity, 39% vs. 45%, respectively); after enhancement, both modes were equivalent (sensitivity, 100% vs. 100%; specificity, 95% vs. 95%, respectively). Signal enhancement resulted in a significant improvement in sensitivity and specificity (P < 0.01). Typical signs of malignancy were irregular vessel calibers, serpiginous courses, penetration of the tumor's margin, and irregular reticular vascularization. The quantitative parameters proved not to be helpful for the differential diagnosis of breast tumors. CONCLUSIONS: By improved analysis of the vascularization pattern, d-galactose-enhanced color Doppler sonography was found to provide more reliable differential diagnostic information than unenhanced Doppler ultrasound in tumors and tumorlike lesions of the breast.

Tumor vascularization in experimental melanomas: correlation between unenhanced and contrast enhanced power Doppler imaging and histological grading.

The purpose of this study was to evaluate the reliability of unenhanced and enhanced power Doppler sonography in visualization of intratumoral angioneogenesis. Thirty-seven malignant melanomas, which had been implanted intra- or subcutaneously in 22 mice, were examined. Various B-mode criteria, power Doppler criteria and spectral Doppler parameters were evaluated before and after IV-application of the d-galactose-based contrast agent Levovist. After sonographic examination, all tumors were analyzed histologically with semiquantitative grading of tumoral vascularization. Unenhanced, in 70% of the tumors, no intratumoral vessels were visible using power Doppler, but only in 11% of the intracutaneous and in 0% of the subcutaneous after injection of the contrast agent. The enhanced mode was definitely superior to unenhanced Doppler in showing the intratumoral vascularity. The intratumoral vascular structure could be sufficiently analyzed in 30% of all tumors by unenhanced Doppler, but in 92% enhanced. The mean percentage vessel area increased about 433% after application of Levovist (intracutaneous: 485%, subcutaneous: 280%). Despite the missing direct correlation between the sonographically and histologically determined grade of tumor vascularization (Pearson's correlation unenhanced 0,356, p <.05/enhanced 0.395, p <.05), the correlation between the percentage vessel area and the histologic grade of vascularization was improved after application of the contrast agent (Pearson's correlation unenhanced 0.347, p <.05/enhanced 0.686, p <.01). We did not find a significant direct correlation between histologically and sonographically determined degree of vascularization. However, the correlation was improved using a d-galactose-based signal-enhancing agent in power Doppler sonography.

Relationships between physical dose quantities and patient dose in CT.

Patient dose in CT is usually expressed in terms of organ dose and effective dose. The latter is used as a measure of the stochastic risk. Determination of these doses by measurements or calculations can be time-consuming. We investigated the efficacy of physical dose quantities to describe the organ dose and effective dose. For various CT examinations of the head, neck and trunk, organ doses and effective doses were determined using conversion factors. Dose free-in-air on the axis of rotation (Dair) and weighted computed tomography dose index (CTDIw) were compared with the absorbed doses of organs which are located totally within the body region examined. Dose-length product (DLP) was compared with the effective dose. The ratio of the organ dose to CTDIw was 1.37 (0.87-1.79) mSv mGy-1. DLP showed a significant correlation with the effective dose (p < 0.005). The average ratio of effective dose to DLP was 0.28 x 10(-2) mSv (mGy cm)-1 for CT of the head, 0.62 x 10(-2) mSv (mGy cm)-1 for CT of the neck and 1.90 x 10(-2) mSv (mGy cm)-1 for CT of the trunk. CTDIw and DLP can be used for estimating the organ dose and effective dose associated with CT examinations of the head, neck and trunk.

[Quantification of signal modulation of hematopoietic bone marrow in gradient echo sequences. Results of phantom and proband studies with simultaneous determination of T2* relaxation times]. / Quantifizierung der Signalmodulation des blutbildenden Knochenmarkes in Gradienten-Echo-Sequenzen. Ergebnisse von Untersuchungen am Phantom und an Probanden mit gleichzeitiger Bestimmung der T2-Relaxationszeit.

The signals from spongy bone on gradient echo sequences depend on the fat and water proton content as well as the differences in magnetic susceptibility at the border between the trabeculae and the bone marrow. From the signal intensities for different echo times, signal modulation was quantified by a special algorithm and at the same time the T2 relaxation time was calculated. Using a fat-water phantom, it was shown that the product of the initial fat and water signal intensity (modulation coefficient) is applicable to indicate the extent of signal modulation and thereby the chemical shift and, moreover, to indicate changes in the fat/water ratio sensitively. In 16 individuals of different ages (23 to 64 years, average 42.4 years) there was a tendency for the T2 relaxation time from the spongiosa of lumbar vertebrae to increase with age, this can be explained by a reduction in the trabecular content, causing reduction in the magnetic inhomogeneity of the bone marrow. The results indicate the usefulness of the sequence and the mathematical model for evaluating the spongy bone in cases of osteoporosis and of malignant haematological disorders.

[The efficacy of lead shielding in patient dosage reduction in computed tomography]. / Effektivität der Bleiabdeckung zur Dosisreduktion beim Patienten in der Computertomographie.

PURPOSE: Investigation of the efficacy of lead apron, testis capsule and thyroid collar for dose reduction in uterus, ovaries, testes and thyroid gland in computed tomography examinations. METHODS: At an Alderson-Rando phantom dose of uterus, ovaries, testes and thyroid gland was measured with thermoluminescent dose meters. CT of the upper abdomen, the whole abdomen and the skull were simulated without and with lead shielding. As lead shielding, a lead apron was attached around the pelvis of the phantom in case of CT of the upper abdomen, a testis capsule was used in CT of the whole abdomen and a thyroid collar in CT of the skull. RESULTS: In CT of the upper abdomen the lead apron did not lead to any recognisable dose reduction in uterus and ovaries. In CT of the whole abdomen the testis capsule led to a dose reduction in testes of 95% (1.39 mSv) and in CT of the skull the thyroid collar to a dose reduction in thyroid gland of 23% (0.19 mSv). CONCLUSIONS: In abdominal CT examinations the testis capsule is an important instrument to reduce the dose of the testes whereas the lead apron is not appropriate for a dose reduction in the uterus and ovaries. In CT of the skull the thyroid collar can remarkably reduce the scattered radiation exposure of the thyroid gland and should be recommended.

[The digital reprocessing of underexposed x-rays. Studies with a fluorescent light scanner]. / Digitale Nachbearbeitung von unterbelichteten Röntgenaufnahmen. Untersuchungen mit einem Fluoreszenzlichtscanner.

Incorrect exposure of conventional radiographs frequently leads to repetition of the examination and thereby to increased radiation exposure for the patient. Underexposed films of an Alderson-Rando phantom, an ankle joint and a patella were digitised by means of an inexpensive fluorescent light scanner, and subsequent image manipulation improved quality so as to make the image diagnostically adequate. For the demonstration of markedly underexposed structures digitalisation with subsequent contrast enhancement was used. Well exposed structures are best evaluated in contrast enhanced transmitted light. Our results suggest it should be possible to reduce the number of repeat exposures and thereby to limit radiation exposure.

[Calculated organ doses and effective dosage for computerized tomography examination of the thorax and abdomen: are these doses realistic?]. / Berechnete Organdosen und effektive Dosis für die computertomographische Untersuchung des Thorax und des Abdomens: Sind diese Dosen realistisch?.

PURPOSE: To analyse how far dose calculations for the CT examination of the thorax and abdomen can lead to faulty estimations of organ doses and effective dose due to differences in the topographic anatomy between mathematical phantom and man. METHODS: For the CT examination of the thorax, upper abdomen, pancreas, pelvis and the entire abdomen, organ doses were calculated with conversion factors, first with regard to the topographic relation within the phantom, then with additional regard to the real anatomy of the man. RESULTS: In the phantom, the abdomen lies outside the scan volume in case of CT-examination of the thorax and the whole intestine outside the scan volume in case of CT-examination of the upper abdomen and the pancreas, whereas the entire intestine is directly exposed in case of CT-examination of the pelvis. Dependent on whether dose calculations take real anatomy into account, doses of special organs can differ by a factor greater than 15. The calculated effective doses differ by a factor less than 1.5. CONCLUSIONS: Calculations of organ doses for the CT examination of the thorax and abdomen can lead to considerable errors due to different topographic relations between phantom and man. In contrast the calculated effective dose is realistic. Hence, dose calculations with the help of mathematical phantom is an efficient method to estimate the total radiogenic risk.

[Value of contrast-enhanced ultrasound vs. CT and MRI in palpable enlarged lymph nodes of the head and neck]. / Wertigkeit der kontrastmittelverstärkten Sonographie von Lymphknotenvergrösserungen im Kopf-Hals-Bereich versus Computertomographie und Magnetresonanztomographie.

PURPOSE: To compare the value of B-mode-, plain and contrast enhanced color Doppler ultrasound, CT and MRI with respect to their diagnostic accuracy in palpable enlarged cervical lymph nodes. MATERIAL AND METHODS: Thirty patients (18 - 90 years old) with palpable enlarged lymph nodes of the head and neck underwent B-mode-ultrasound, plain and contrast enhanced color Doppler, CT and MRI (gold standard: histologic analysis in 22 and clinical follow up for at least six months in eight patients). The criteria of malignancy were maximal and minimal lymph node diameter, M/Q-ratio, various morphologic criteria (necrosis, hilus line, internal structure, contour, contrast enhancement), spectral Doppler indices, and vascular architecture in color Doppler. RESULTS: The highest sensitivity (= 1.00, specificity = 0.07 - 0.15) was obtained measuring the lymph node diameter independent on the used imaging modality (ultrasound, CT, MRI), the highest specificity (= 1.00, sensitivity = 0.71) analyzing the vascularity of the lymph node by plain color Doppler. The highest diagnostic (= 0.93) accuracy was delivered by contrast enhanced color Doppler analysis of the vascularity. Sensitivity (= 0.94) and specificity (= 0.92) of this imaging modality were only slightly inferior to the top values. Fisher's exact test revealed significant values in differentiating malignant from benign lymph nodes for B-mode- and MR-analysis of the M/Q-ratio (p < 0001/p < 0.05), B-mode morphology (p < 0.00005), plain and contrast enhanced color Doppler analysis of the vascularity (p < 0.0001/p < 0.000005), MR-morphology (p < 0.0001), and CT-morphology (p < 0.005). CONCLUSION: CT is inferior to MRI, B-mode-ultrasound and contrast-enhanced color Doppler in the differential diagnosis of selectively analyzed, palpably enlarged cervical lymph nodes using the criteria of our study. The analysis of the MR-morphology revealed a slightly inferior diagnostic accuracy to B-mode morphology and color Doppler analysis of the vascularity.

[Analysis of vascularity in breast tumors--comparison of high frequency ultrasound and contrast-enhanced color harmonic imaging]. / Vaskularisationsanalyse bei Mammatumoren--Vergleich von Hochfrequenzsonographie und Kontrast-Colour-Harmonic-Imaging.

PURPOSE: To compare the ability of standard power Doppler and color harmonic imaging for visualising breast tumor vascularity using ultrasound probes of various frequencies, and to evaluate the influence on diagnostic accuracy using ultrasound contrast agent. MATERIALS AND METHODS: Twenty patients (x = 43.6 +/- 11.7 years) with suspected malignancy of the breast underwent power Doppler to evaluate vascularity and to offer a differential diagnosis of the lesion. Two criteria were used for differential diagnosis: The quantitative extent of vascularity ("percentage vessel area", PVA) and the qualitative assessment of vascular architecture. The following power Doppler modes were compared in every patient: Plain and enhanced (Levovist(R)) 9 MHz and 12 MHz standard power mode and enhanced 9 MHz color harmonic imaging-(CHI). RESULTS: The PVA increased from a mean of 2.2 +/- 2.9 % (9 MHz standard plain) via 4.8 +/- 4.1 % (12 MHz standard plain), 9.7 +/- 15.3 % (9 MHz standard enhanced), 17.4 +/- 20.0 % (9 MHz CHI enhanced) up to 19.4 +/- 14.8 % (12 MHz standard enhanced). The perceptibility of the vascular structure was best using the enhanced 12 MHz standard power mode, immediately followed by the enhanced 9 MHz CHI mode. The improved detection of vascular signal did not translate into improved diagnostic accuracy. The highest diagnostic accuracy (95 %) was obtained using the enhanced 9 MHz CHI mode (criterion "PVA") and the enhanced 9 MHz standard power mode (criterion "vascular structure"), whereas the 12 MHz probes delivered insufficient diagnostic accuracy and very low specificity. CONCLUSION: Best quantitative and qualitative visualisation of the tumor vascularity was achieved using the enhanced 12 MHz standard power mode. Nevertheless, the highest diagnostic accuracy was obtained using enhanced 9 MHz standard power Doppler and enhanced 9 MHz color harmonic imaging. The visualisation of tumor vascularity and, partially, the diagnostic accuracy are improved significantly by color harmonic imaging without changing the probe frequently.

[Intravenous spiral CT angiography for assessment before orthotopic liver transplantation: comparisons between tomography, MIP, 3-dimensional surface imaging and intra-arterial DSA]. / Intravenöse Spiral-CT-Angiographie zur Evaluation vor orthotoper Lebertransplantation: Vergleiche zwischen Schnittbilddarstellung, MIP, dreidimensionaler Oberflächendarstellung und intraarterieller DSA.

UNLABELLED: To analyse the efficacy of intravenous spiral CT angiography (SCTA) for the evaluation before orthotopic liver transplantation (oLT) compared with DSA. METHODS: Spiral CT was performed on 31 potential recipients of a liver graft in order to examine hepatic vessels, coeliac axis, splenic artery and superior mesenteric artery. The arterial vessels were reconstructed in "Maximum Intensity Projection (MIP)" and "Shaded Surface Display (SSD)"-technique. The axial images, MIP and SSD were compared in 25 patients with DSA with regard to the visualisation of the vascular anatomy, detectability of stenosis and vascular diameters. RESULTS: The type of arterial liver supply could be determined via SCTA in all patients. Stenosis of the coeliac axis was seen in ten patients on the DSA, MIP and SSD and in eight patients on the axial images. Occlusion of the hepatic artery was clearly visualised in two patients on the DSA, axial images and MIP and in one patient on the SSD. There was no false positive diagnosis with SCTA. SSD was seen as the best technique to visualise the vessels without overshadowing. There were no significant differences between the diameters measured from the axial images, MIP and SSD images in transversal direction and the DSA images (p > 0.05). CONCLUSION: SCTA is a greatly promising method for the imaging of vessels supplying the liver before oLT, and may convey more diagnostic information than DSA.

[Spiral CT of the pancreas. A clinical comparison with conventional CT and dynamic CT]. / Spiral-CT des Pankreas. Klinischer Vergleich mit der konventionellen CT und der dynamischen CT.

PURPOSE: Spiral CT is compared with the dynamic CT and the conventional CT with regard to the enhancement of the pancreas and peripancreatic vessels and the visualisation of anatomic details. METHODS: In 15 patients spiral CT of the pancreatic region was performed in the arterial phase followed by spiral CT of the upper abdomen in the arterial-venous phase. In 30 patients dynamic CT (n = 15) and spiral CT (n = 15) of the pancreatic region was performed in the arterial phase followed by conventional CT of the upper abdomen. RESULTS: Compared with dynamic CT, spiral CT of the pancreatic region in the arterial phase (flow 4 ml/s, delay 15-18 s) leads to a stronger contrast of the peripancreatic vessels (p < 0.001) and the pancreas (108 vs. 86 HU) (p < 0.05). In the following spiral CT of the upper abdomen (flow 1 ml/s, delay 70 s), a high enhancement of both arteries and veins could be achieved. Intrapancreatic structures and peripancreatic vessels were better seen in the spiral CT than in the conventional CT (p < 0.05) and p < 0.005, respectively). CONCLUSION: The combination of spiral CT of the pancreatic region in the arterial perfusion phase and spiral CT of the upper abdomen in the arterial-venous phase enables an optimal enhancement of the pancreas and the abdominal vessels and a reliable visualisation of anatomic details.

[Doppler sonographic monitoring control of perfusion of hepatocellular carcinoma after arterial chemoembolization]. / Dopplersonographische Verlaufskontrolle der Perfusion hepatozellulärer Karzinome nach arterieller Chemoembolisation.

INTRODUCTION: 22 patients with hepato-cellular carcinomas were examined sonographically before and after intra-arterial chemo-embolisation. The aim was to evaluate different techniques for judging tumour morphology and for assessing changes in perfusion. MATERIAL AND METHODS: The morphological appearances and perfusion changes were analysed by means of colour coded duplex sonography and power Doppler sonography before and after intravenous contrast medium. Pulsatility (Pl) and resistance index (RI) were used as quantitative parameters for judging changes in perfusion. RESULTS: In 13 patients intra-tumoral arteries were identified by duplex sonography and in four patients only by the power Doppler procedure. In three patients arterial vessels could only be identified after intravenous contrast. In 9 patients it was possible to document a reduction in arterial perfusion following embolisation. The indices calculated from these findings gave no prognostic indication. DISCUSSION: The methods described give information concerning changes in perfusion of a tumour following chemo-embolisation and, in conjunction with CT and clinical findings, provide indications for further tumour embolisation.