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[Dual phase spiral CT in hepatic hilar masses]

Year 1998
Stietzel C. Kosling S.
Klinik und Poliklinik fur Diagnostische Radiologie, Universitat Leipzig.
PURPOSE: To develop optimal parameters for dual-phase spiral CT and to test it in hepatic hilar processes. METHODS AND MATERIALS: 15 patients without and 20 patients with suspected hhp underwent dual-phase spiral CT. Maximum intensity projections (MIPs) of arterial and portal venous phase were calculated for assessment of relation between hhp and hepatic hilar vessels. RESULTS: Optimal parameters were: 150 ml contrast material with 4 ml/s, 20-s delay, 24-s spiral duration, 5 mm slice thickness, 7-8 mm/s table speed, 2 mm reconstruction increment. The localisation and spread of hhp could be optimally estimated on axial scans. Various hhp showed a different type of enhancement. 12 of 20 lesions caused an alteration of hepatic vessels. CONCLUSION: Dual-phase spiral CT is valuable in characterising and assessing spread and operability of hhp. The calculation of MIPs should be performed only when preparing an operation.

[Doppler sonographic monitoring control of perfusion of hepatocellular carcinoma after arterial chemoembolization]

Year 1998
Steger W. Vogl TJ. Hosten N. Steger S. Hidajat N. Felix R.
Strahlenklinik und Poliklinik, Virchow Klinikum, Humboldt-Universitat Berlin.
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.

[Value of dual-phase-helical CT in the preoperative diagnosis of pancreatic cancer--a prospective study]

Year 1998
Lehmann KJ. Diehl SJ. Lachmann R. Georgi M.
Institut fur Klinische Radiologie, Klinikum Mannheim der Universitat Heidelberg.
PURPOSE: A prospective study was performed to evaluate the accuracy of dual phase helical CT in suspected pancreatic cancer. METHODS: Within one year 136 patients underwent helical CT with arterial and portal venous scans after bolus tracking and NaCl bolus injection. Evidence of pancreatic cancer and assessment of resectability were recorded using a standardised protocol. Suspected benign disease was verified by follow-up examination and clinical data, suspected malignant disease was correlated with biopsy or surgery. RESULTS: For the detection of tumor the overall concordance was 92%, the sensitivity 98% and the specificity 70% (6 false positive, 1 false negative). Resectability was correctly assessed in 90% with a sensitivity of 92% and a specificity of 88% (4 false positive, 4 false negative). Vascular invasion was detected correctly in 91% (veins)-94% (arteries), lymph node invasion in 67% and liver metastasis in 94%. CONCLUSION: Dual phase helical CT is a very reliable tool in the assessment of resectability in pancreatic cancer.

[T1-weighted dynamic MRI with new superparamagnetic iron oxide particles (Resovist): results of a phantom study as well as 25 patients]

Year 1998
Muller M. Reimer P. Wiedermann D. Allkemper T. Marx C. Tombach B. Rummeny EJ. Shamsi K. Balzer T. Peters PE.
Institut fur Klinische Radiologie, Westfalische Wilhelms-Universitat Munster.
PURPOSE: Evaluation of the diagnostic usefulness of the T1-effect of Resovist (SPIO) for dynamic MRI of the liver. METHOD: In-vitro measurements of a dilution series with T1-weighted FLASH and SE sequences and investigation of 25 patients with known focal liver lesions with a T2-weighted TSE sequence and a dynamic T1-FLASH sequence. RESULTS: T1-weighted MRI with Resovist in vitro showed a positive enhancement at low concentrations and a negative enhancement at higher concentrations. In-vivo T1-weighted dynamic MRI liver parenchyma demonstrated a positive enhancement 30 s post contrast, followed by a continuous slope of signal intensity and a negative enhancement (> or = 60 s). Spleen, portal venous vessels and haemangiomas showed an early increase in signal intensity followed by a decreasing positive enhancement, but without negative enhancement. During the perfusion phase metastases showed a small but not significant increase in signal intensity. In 80% a positive ring enhancement could be observed around metastases. CONCLUSION: Resovist exhibits a diagnostically useful T1-effect. An evaluation of the perfusion of focal liver lesions during the distribution phase is possible with dynamic T1-weighted MRI. This approach may further improve characterisation of focal liver lesions.

[When is it meaningful to support magnetic resonance tomography by administering a positive enteral contrast medium?--an account of practical experience]

Year 1998
Hosten N. Hoffmann KT. Pflasterer-Schonsiegel M. Keske U. Felix R.
Strahlenklinik und Poliklinik, Virchow-Klinikum der Humboldt-Universitat zu Berlin.
PURPOSE: To evaluate in which parts of the gastrointestinal tract and in what clinical situations the diagnostic quality of MR examination may be improved by a positive enteral contrast agent. METHODS: MR examinations of 37 patients performed before and after application of a Gadolinium-DTPA preparation suitable for oral and rectal application were evaluated. Exams were evaluated by two independent observers. Neoplastic disease of the gastrointestinal tract constituted the majority of indications followed by inflammatory changes and extraenteral space-occupying lesions. RESULTS: The majority of examinations (62%) were improved by the application of enteral contrast agent. No effect was observed in 35%; in two patients image quality was poorer after contrast application. The benefit of enteral contrast agents was highest in MR examinations of the sigma and rectum. The enteral contrast agent was most valuable in the detection of lymphoma if an evaluation according to indication was performed. CONCLUSION: In selected cases, the diagnostic quality of abdominal MRI can be improved by the application of an enteral contrast agent. Apart from the effect of greater signal intensity, the contrast agent does complement MR imaging by a functional aspect.

[CT guided percutaneous drainage of retro- and extraperitoneal abscesses and fluid collection]

Year 1998
Risse JH. Keulers P. Gunther RW.
Klinik fur Radiologische Diagnostik, Universitatsklinikum der RWTH Aachen.
PURPOSE: Evaluation of course, success rate and complications after CT-guided percutaneous drainage of retroperitoneal and extraperitoneal abscesses and fluid collections (PAFD). METHODS: Retrospective review of 47 PAFD in 42 consecutive patients (27 male, 15 female, age 58 [27-80] years) over a period of 7 years was performed. RESULTS: 47 clinically suspected abscesses proved to be 40 abscesses, three haematomas and 4 lymphoceles. Primarily, 67 drainage catheters were needed, which included three catheters in 4 patients and 4 catheters in one patient. Drainage time averaged 17.6 days (2-50). The most frequent drainage location was the iliopsoas region (27/47 collections). The cure rate was 87.2% (41/47 collections). Temporization was achieved in 8.5% (4/47); there were two drainage failures (one sepsis, one recurrence). No major complications were observed. Three catheter dislocations occurred as minor complications. CONCLUSION: CT-guided percutaneous drainage of retroperitoneal and extraperitoneal abscesses and fluid collections is safe, with a high cure rate and few complications.

[Stereo display of MR angiograms]

Year 1998
Georgi M. Gaa J. Misri H. Koepke J.
Klinikum Mannheim der Universitat Heidelberg.
PURPOSE: To provide methods for stereoscopic visual demonstration from 3D reconstructed MR angiographic images. METHODS: Stereoscopic viewing can be obtained with pairs of images that are displayed at angles of 15 degrees. Optical devices as stereoscopic binoculars or minor stereoscopes facilitate stereoscopic viewing. The possibility of stereoscopic projections for a larger auditorium is mentioned. RESULTS: Using three clinical examples the advantages of stereoscopic display of MR angiograms are demonstrated. CONCLUSIONS: MR angiography allows stereoscopic viewing with simple methods, like CT- and conventional rotation angiography. This principle, which has been known for 100 years, may thus acquire a new significance.

[MRI with supermagnetic iron particles versus double-spiral CT in identification of malignant liver lesions]

Year 1998
Muller RD. Vogel K. Neumann K. Hirche H. Barkhausen J. Stoblen F. Henrich H. Langer R.
Zentralinstitut fur Rontgendiagnostik, Universitatsklinikum Essen.
PURPOSE: The purpose of this study was to evaluate the efficacy of MRI with superparamagnetic iron oxide (SPIO) and double-spiral CT in the detection of liver metastases and hepatocellular carcinoma. METHODS: 38 patients with a total of 144 malignant hepatic lesions underwent CT and MRI. A panel of experts defined the gold standard. Five experienced judges performed independently blinded evaluation of the number of detectable lesions. Multifactorial variance analysis was used to determine the statistical significance. RESULTS: SPIO-MRI shows the highest rate of detection and is significantly superior to native MRI and native CT. The highest rate of detection by CT is shown in the portal-venous phase of contrast; nevertheless, the rate is significantly inferior to SPIO-MRI. In general, the native phases of CT and MRI are significantly inferior to the contrast phases of both. SPIO-MRI shows a higher rate of false positive findings. CONCLUSION: The time-consuming and cost-intensive SPIO-MRI significantly increases the rate of detectability for malignant liver lesions compared with double-spiral CT but it also increases the rate of false positive findings.

[TIPSS: 10 years of clinical experience]

Year 1998
Richter GM. Noldge G. Brado M. Scharf J. Simon C. Hansmann J. Radeleff B. Kauffmann GW.
Abteilung fur Radiologische Diagnostik, Universitatsklinik Heidelberg.
To demonstrate and document 10 years of clinical experience gathered by us with TIPSS and to discuss achievements, problems and outlook. MATERIAL AND METHODS: The analysis is based on the following parameters: portosystemic gradient; morphological delineation of the portal circulation; determination of the portal perfusion fraction (PPF) and the total liver perfusion (GLP); arterial flow changes; hepatic encephalopathy; incidence of restenotic shunt occlusion and recurrent variceal bleeding. RESULTS: Variceal filling was widely reduced by TIPSS, and significantly reduced portal liver perfusion as assessed morphologically and rheologically. However, there was an immediate onset of compensated liver perfusion by increased arterial inflow. Total liver perfusion did not change significantly. In TIPSS portal decompression was readily achieved, the portosystemic gradient dropping from an average of 24 mm Hg to 10.5 mm Hg. In our series we could not demonstrate an increased incidence of hepatic encephalopathy during the 30-day post-TIPSS period. Early mortality was 4% and early rebleeding rate 3%. The 12-month re-intervention rate based on an invasive portography follow-up protocol was 76%, and the 24-month re-intervention rate was 90%. The definite occlusion rate was below 5%. Beyond a follow-up time span of 24-months the necessity for re-intervention dropped significantly: less than one-third of our patients required some sort of re-intervention. CONCLUSION: The concept of TIPSS represents an individually calibrated H-shunt. The significant reduction of post-TIPSS portal perfusion appears to be compensated by increased arterial inflow. This is reflected by an invasive flow measurement results and by the clinical results. Lethality of TIPSS is low mostly as a result of a refined technique, careful patient selection, follow-up care and meticulous shunt surveillance.

[Ultra-rapid T2-weighted MR imaging during suspended respiration for the examination of focal lesions of the liver: a comparison of TSE, HASTE and HASTE-STIR sequences using a CP body array coil]

Year 1998
Brinkmann G. Musiolik I. Kuhn B. Steffens JC. Wesner F. Graessner J. Muhle C. Heller M.
Klinik fur Radiologische Diagnostik, Christian-Albrechts-Universitat zu Kiel.
PURPOSE: A comparison of ultra rapid T2-weighted HASTE and HASTE-STIR sequences during suspended respiration for the detection of focal lesions of the liver. MATERIAL AND METHODS: Twenty-one patients (59 +/- 12 years) with a total of 33 focal lesions (7 < or = 1 cm, 19 < or = 3 cm; 17 cystic liquid and 16 solid lesions) were examined with a 1.5 T MR apparatus. Sequences: T2 weighted HASTE (TEeff = 64 ms, 90 ms), HASTE-STIR (TEeff = 64 ms, 81 ms) TSE (TE = 132 ms) and T1-weighted FLASH 2D. RESULTS: The T2-weighted TSE and both HASTE sequences showed all the lesions. Two out of the 33 lesions were not demonstrated by the other sequences. Best image quality without movement artefacts and the best resolution of the lesions in the T2-weighted sequences, with the most favourable contrast/noise ratio (36.6 +/- 33.1) and signal/noise ratio (20.8 +/- 10.5) resulted from the HASTE 90, followed by the HASTE 64 sequence (27.5 +/- 24.2; 24.6 +/- 9.1). Both these techniques were superior to the TSE sequence (23.9 +/- 29.4; 13.9 +/- 7.4), which resulted in movement artifacts. With the HASTE-STIR sequences it was possible to show 31 and 32 of the 33 lesions respectively, with very good resolution but poor signal/noise ratio. CONCLUSION: HASTE sequences have the potential of improving the diagnosis of focal liver lesions.

[RARE urography in pelvic tumors: diagnostic ranking and comparison with intravenous pyelography]

Year 1998
Pawlik H. Laubenberger J. Gufler H. Langer M.
Radiologische Universitatsklinik, Abteilung Rontgendiagnostik, Albert-Ludwigs-Universitat, Freiburg.
PURPOSE: To examine if RARE urography may replace conventional intravenous urography in patients with suspected urinary obstruction in pelvic tumours. MATERIALS AND METHODS: In a prospective trial on 120 patients with pelvic tumours scheduled for operation, biplanar RARE urography was performed and compared to conventional intravenous urography and ultrasound findings. RESULTS: In 30 out of 120 patients an ureteric obstruction was diagnosed by ultrasound. Sensitivity of RARE urography for obstruction was 98% as compared to 60% in conventional intravenous urography. In 12 patients additional retrograde cystoureterography showed a sensitivity of 83%. Specificity of RARE urography and intravenous urography was 100%. In combination with axial MR tomography RARE urography yielded a more precise localisation of the site of obstruction and the underlying cause (98%) as compared to conventional urography (60%) and ultrasound (56%). CONCLUSION: By use of RARE urography urinary obstruction can be reliably demonstrated or ruled out. Combining RARE urography with tomographic MR imaging allows the precise depiction of the site of the obstruction and may demonstrate the underlying pathology.

[Native and signal-enhanced power Doppler sonography for characterization of liver lesions]

Year 1998
Strunk H. Stuckmann G. Frohlich E. Textor J. Wilhelm K. Hortling N. Remig J.
Radiologische Universitatsklinik Bonn.
PURPOSE: To evaluate the characterisation of liver lesions using power Doppler sonography before and after intravenous injection of the ultrasound contrast agent Levovist. MATERIALS AND METHODS: 39 patients with 41 liver lesions (10 haemangiomas, 2 focal nodular hyperplasias (FNH), 2 focal fatty infiltrations, 1 echinococcal lesion, 11 hepatocellular carcinomas, 14 metastases and one cholangiocarcinoma) were evaluated prospectively. Power Doppler images before and after intravenous injection of the ultrasound contrast agent Levovist were analysed by two radiologists and one gastroeterologist, who subjectively classified the distribution (peripheral, central, diffuse) and amount (none, minimal, moderate and strong) of flow pattern in each sonographic examination. Histological verification was obtained in all liver lesions, except in haemangiomas, where MR imaging and in one FNH where scintigraphy was regarded as sufficient proof. RESULTS: On the whole, power Doppler sonography after contrast injection was superior to unenhanced power Doppler-sonography in 20 liver lesions and equal in 7. After contrast injection, previously visible flow was enhanced in 14 patients, in 6 lesions flow was detected, which was not seen before in the power mode. Moderate or strong flow signals were detected before contrast injection in 8/26, post contrast injection in 18/26 malignant tumours. Contrawise, 13/15 benign lesions did show any or only minimal flow signals before and 10/15 after contrast injection. CONCLUSION: Intratumoural flow signals favour a malignant tumour. The absence of flow signals is a frequent finding in benign lesions but does not rule out malignancy.

[TIPSS: technical and clinical results after 4 years]

Year 1998
Textor HJ. Brensing KA. Wilhelm K. Strunk H. Block W. Raab P. Hofer U. Muller-Miny H. Layer G. Schiedermeier P. Schuller H. Sauerbruch T. Schild HH.
Radiologische Universitatsklinik, Universitat Bonn.
PURPOSE: Retrospective analysis of the technical and clinical results after transjugular portosystemic stent shunt (TIPSS) procedure. METHOD: Between 1992 and 1996 we tried to establish a TIPSS in 90 patients. The indications were: recurrent variceal haemorrhage (n = 74), refractory ascites (n = 12), hepatorenal syndrome (HRS) (n = 4). Due to advanced liver cirrhosis 16 patients suffered of severe renal dysfunction (HRS). 57 patients had ascites. RESULTS: TIPSS implantation was technically successful in 96.7% (1992-1994: 5.1%, 1995-1996: 100%) of the patients. Complications occurred in 14.9% (1992-1994: 25.6%, 1995-1996: 6.3%). TIPSS-associated mortality was 2.3% (1992-1994: 5.1%, 1995-1996: 0%). 76.1% of the patients required reinterventions. 85.3% of reinterventions were necessary in the first year after TIPSS placement. The survival rate without reintervention was 28%, 21% and 9% for Child A, B, and C patients, respectively. Recurrent variceal haemorrhage occurred in 12.7%. De novo hepatic encephalopathy developed in 13.8%. Ascites improved in 79.2% and renal function in 75% of the patients. CONCLUSION: TIPSS is an effective method to treat recurrent variceal haemorrhage, refractory ascites and HRS. Complication and mortality rate depend on the investigator's experience and on the technique used.

[Intra-arterial calcium stimulation for preoperative localization of insuloma]

Year 1998
Pereira PL. Dammann F. Schott U. Huppert PE. Duda SH. Teichmann R. Claussen CD.
Klinik fur Radiologie, Abteilung Radiologische Diagnostik, Eberhard-Karls-Universitat Tubingen. philippe.pereira@med.uni-tuebingen.de
PURPOSE: Objective is to evaluate the efficacy of the intraarterial calcium test in the preoperative localisation of insulinomas. MATERIAL AND METHOD: To stimulate the pathological release of insulin, calcium gluconate (0.015 meq Ca++/kg) was selectively injected into the arteries supplying the pancreas. Prior to calcium injection and 30, 60, 90 and 120 seconds later, 5 ml samples of blood were obtained from the right or from both right and left hepatic veins. Insulin levels were then determined by mean of immunoassays. A twofold increase in insulin level in the venous sample after 30 or 60 seconds localised the insulinoma to the region of the pancreas supplied by the selectively injected artery. Results of the calcium test were prospectively analysed in 6 patients and compared with operative findings. RESULTS: All 6 patients had a surgically proved solitary and benign insulinoma. Calcium stimulation with venous sampling provided true-positive localisation of insulinomas in all patients without suspicion of liver metastasis. All 6 patients currently have normal insulin levels after a mean period of 16 months (range 4-24 months) with no evidence of hypoglycaemia on fasting. CONCLUSION: Intraarterial stimulation with calcium and hepatic vein samplings for insulin gradients is a very sensitive minimally invasive functional method and may replace transhepatic portal venous samplings for the preoperative detection of insulinomas.

[Emergency decompression of a mechanical colonic ileus before elective surgery: first clinical results of fluoroscopic stent placement]

Year 1998
Knopfle E. Wamser G. Mayer H. Zugel N. Bohndorf K.
Klinik fur Diagnostische Radiologie und Neuroradiologie, Zentralklinikum Augsburg.
PURPOSE: Evaluation of fluoroscopic stent placement as an emergency therapeutical approach for treatment of acute large bowel obstruction due to colorectal neoplasm. METHODS AND MATERIAL: From January to December 1996 in 11 patients suffering from colorectal stenosis due to known or supposed malignancy the indication for the fluoroscopic placement of self-expanding metal stents was established. All patients showed clinical and radiological signs of an acute mechanical large bowel obstruction. Elective single-stage surgery was planned if the decompression had been carried out successfully. RESULTS: Stent placement was successful in 8 cases. Functional success in respect of resolving the acute large bowel obstruction was seen in 7 out of 11 patients. Elective surgery was possible in all 7 cases creating a primary end-to-end anastomosis without major complications during the perioperative period. CONCLUSION: Fluoroscopic placement of self-expanding metal stents in malignant colorectal stenosis is a promising method to avoid emergency surgery.