[MRT in nonpalpable testes]. / MRT bei nichttastbaren Hoden.

Magnetic resonance imaging was performed in 22 male patients for localisation of 27 nonpalpable undescended testes. The operative verification, carried out in 19 testes (15 patients) served as basis for checking on the accuracy of MRI results and for their comparison with those of sonography and laparoscopy. The impalpable testis was localised via MRI in 13 cases and its lack was correctly established in three cases. There were three false MRI diagnoses. The suspicion of two intraabdominal localised testes were not confirmed at surgery and one intracanalicular testes were not seen by MRI. The low signal intensity of the undescended testes on T2-weighted images is indicative for fibrotic changes and may be of value for more accurate planning of the operative volume. MRI offers a new promising opportunity for localisation and morphologic estimation of the undescended testis and should be performed before the invasive investigation methods.

Focal liver lesions: characterization with nonenhanced and dynamic contrast material-enhanced MR imaging.

PURPOSE: To evaluate prospectively the diagnostic accuracy of non-enhanced and gadolinium-enhanced magnetic resonance (MR) imaging in characterization of hepatic lesions. MATERIALS AND METHODS: Fifty-five patients with benign and 52 patients with malignant focal liver lesions underwent examination at 1.5 T that comprised nonenhanced and dynamic contrast material-enhanced images. Four experienced radiologists independently read the different sets of images without and with knowledge of clinical history. RESULTS: Receiver operating characteristic analysis showed that dynamic contrast-enhanced MR imaging added information to nonenhanced MR studies and thereby improved distinction between benign and malignant lesions (P < .05). Knowledge of clinical data further improved lesion characterization with nonenhanced and combined nonenhanced and contrast-enhanced MR imaging (P < .05). CONCLUSION: Dynamic contrast-enhanced MR imaging is a useful adjunct for characterization of hepatic lesions. Knowledge of clinical history still has a decisive effect on interpretation of MR images of the liver.

[MRT in clinically unclear posttraumatic knee joint lesions]. / MRT bei klinisch unklaren posttraumatischen Kniegelenksläsionen.

An MRI examination was performed on 31 patients with clinically questionable posttraumatic knee joint lesions. A broad range of intra- und extraarticular pathological changes was found. The correlation of MRI with arthroscopy and surgery showed a correct MRI diagnosis in 78% of the meniscal lesions (n = 18) and in 89% of the anterior cruciate ligament ruptures (n = 9). An analysis of false positive and false negative MRI diagnoses was made. MRI offers the opportunity for noninvasive complex assessment of knee joint structures and is of particular value in the diagnosis of posttraumatic knee joint lesions.

Electron microscopic and 31-P NMR studies of ischemic injured rat livers during preservation and reflow.

Ischemic injury induced during preservation and reperfusion contributes to post-operative failure in liver transplantation. Hepatic injury and recovery from preservation was studied in an isolated rat liver model reperfused with oxygenated erythrocytes. In order to correlate morphological and functional findings, 31-P nuclear magnetic resonance spectroscopy and electron microscopy were used to investigate metabolic and ultrastructural changes during 6 hours of reperfusion. Following cold preservation, EM's showed a primary sinusoidal cell injury, whereas the hepatocytes were well maintained. During reperfusion, hepatocytes displayed further damage. The simultaneous presence of vacuolarly degenerated mitochondria and mitochondria of increased activity was noted. 31-P NMP spectra demonstrated initially a partial ATP-recovery. The maximum level of 60% of the control ATP-value could not be further increased. EM and 31-P NMR indicate that the progressive injury to the liver is due to microcirculatory malfunction induced by an endothelial cell damage, followed by injured hepatocytes themselves, and the consequent intracellular energy crisis that is produced.

[The place of computed tomography in the staging of bronchial carcinoma. A retrospective study]. / Der Stellenwert der Computertomographie beim Staging des Bronchialkarzinoms. Eine retrospektive Studie.

The conventional radiological and CT findings in 347 patients with confirmed bronchial carcinomas have been compared. In 184 patients subjected to surgery, the post-operative TNM classification was compared with the pre-operative CT staging. It was found that CT staging of the T-classification was correct in 82% and of the lymph nodes in 62.5% of cases. CT had a sensitivity of 92% and 95% for the recognition of mediastinal and bronchopulmonary lymph nodes, respectively, and a specificity of 68% and 57%. In 163 patients not subjected to surgery the reasons for avoiding operation were also studied. In more than 80% of these patients it was the CT findings which had indicated that the patient was inoperable.

Effect of pentoxiphylline on the recovery of the preserved rat liver: 31P NMR and ultrastructural studies.

Hepatic failure often occurs following transplantation. This is primarily due to cold ischemia during preservation, warm ischemia during implantation, and finally reperfusion damage after transplantation and reflow. The possibility that this ischemia and reperfusion-induced damage can be reduced by preischemic application of a xanthine derivative (pentoxiphylline) was examined using 31P NMR spectroscopy and electron microscopy (EM) studies of bioenergetic and ultrastructural changes in oxygenated erythrocyte-perfused rat livers. EM illustrated that the hepatocytes and the mitochondria appeared to be relatively unaffected by cold preservation of the liver, whereas the endothelial cells lining the sinusoids became disrupted. After reperfusion, NMR spectroscopy showed a partial recovery of ATP levels, and EM indicated progressive mitochondrial injury. This progressive injury to the liver was probably due to endothelial cell damage which resulted in microcirculatory malfunction and free radical formation during reperfusion. Pentoxiphylline pretreated livers showed better preservation of the cell morphology and exhibited better ATP recovery than untreated livers. Pentoxiphylline is known to prevent the loss of precursors of ATP resynthesis by inhibiting AMP dephosphorylation during ischemia and improves the microcirculation via vasodilatory properties following ischemia. Thus, it is concluded that pentoxiphylline may ameliorate ischemia-induced cell damage during transplantation.

[The accuracy of the imaging procedures (sonography, MRT, CT, angio-CT,nuclear medicine) in characterizing liver tumors]. / Treffsicherheit bildgebender Verfahren (Sonographie, MRT, CT, Angio-CT, Nuklearmedizin) bei der Charakterisierung von Lebertumoren.

In a prospective study, an attempt was made to determine the specificity of various imaging methods for defining tumours of the liver rather than their ability to demonstrate them. It was based on 130 patients with histologically confirmed lesions (33 haemangiomas, 17 FNH, 4 hepatocellular adenomas, 28 HCC, 36 adenocarcinoma metastases). The methods were MRT (130 cases), sonography (119), CT (122), dynamic arterial angio-CT (15), 99TC-EHIDA or blood pool scintigraphy (4 FNH, haemangiomas, HCC, 44 cases). MRT showed somewhat better results (accuracy 80%) than CT (73%) and angio-CT (73%) in demonstrating the type of lesion. The results of scintigraphy (53%) and sonography (69%) were rather worse. The range of accuracy for MRT, CT and sonography varied from 94% (haemangiomas with MRT) to 47% (FNH with sonography).

[Value of CEA determination in follow-up of patients with liver metastasis of colorectal cancers with loco-regional chemotherapy]. / Der Stellenwert der CEA-Bestimmung in der Verlaufskontrolle von Patienten mit Lebermetastasen kolorektaler Karzinome unter lokoregionaler Chemotherapie.

The importance of carcinoembryonic antigen as a tumor marker to the follow-up of patients with liver metastases from colorectal cancer was investigated. It was reported about 29 patients receiving chemotherapy. We estimated the effect of therapy according to sonographic and computer tomographic criteria and related to the CEA-level. The correlation of the growth of cancer and the level of the CEA was positive in 81% of the patients. We do not consider as sufficient the measurement of CEA as an exclusive method for the follow-up of colorectal cancer and recommend the monthly measurement of CEA in connection with radiological examinations in the period of 3-4 month.

Percutaneous biopsy of the liver.

Retrospective evaluation of 510 percutaneous CT-guided biopsies of the liver mainly fine-needle aspiration biopsies for cytology (89% of cases), yielded an overall accuracy rate of 92% and a sensitivity of 94%. The relatively high percentage of false-positive diagnoses (7% of all benign tumors) may be reduced by more consistent consideration of possible errors in cytology and a more consistent use of large bore biopsies.

[A frequency analysis and evaluation of the criteria for dynamic CT and a test of the CT diagnosis of space-occupying lesions of the liver]. / Frequenzanalyse und Wertbestimmung von Kriterien der dynamischen CT und Test zur CT-Diagnostik von Leberraumforderungen.

In a retrospective study the findings of dynamic CT investigations in 185 patients with histologically confirmed hepatic masses were analysed and related to 47 criteria which have been described in the literature. The criteria with the highest value for making a specific diagnosis have been defined for seven different lesions (abscess, adenoma, FNH, haemangioma, adenocarcinoma metastases, metastases from other tumours, HCC). We found agreement with the literature in the following: the target phenomenon for abscesses, central scarring for FNH, spreading enhancement for haemangiomas and irregularity of the liver contour in the absence of subcapsular tumours for HCC. By combining a number of criteria it was possible to suggest the type of lesion retrospectively. The predictive value was found to range from 73% to 100%, a definite diagnosis was possible in only 64%.

[Dynamic MRT after Gd-DTPA administration in kidney transplants: the susceptibility and T2 effects]. / Dynamische MRT nach Gd-DTPA-Applikation bei Nierentransplantaten: Suszeptibilitäts- und T2-Effekte.

35 kidney transplanted patients (15 without pathological findings and 20 with histologically proven chronic rejection) were investigated with a combination of dynamic MR and bolus application of Gd-DTPA. The occurrence of susceptibility artifacts and T2 effects at the junction between papilla and renal calix were analysed. There are two groups of patients. The first one shows only artifacts due to susceptibility. The second group indicates the so-called "dark ring pattern" (susceptibility artifacts and T2 effects). These effects are discussed in terms of their dependence on concentration and their dependence on the degree of transplant malfunction. The appearance of "dark-ring patterns" and of susceptibility artifacts indicate the functional status of the glomerular filters.

[The rational use of imaging technics for the diagnosis of abdominal tumors with particular reference to magnetic resonance tomography]. / Rationeller Einsatz bildgebender Verfahren für die Diagnostik von Tumoren des Abdomens unter besonderer Berücksichtigung der Magnetresonanz-Tomographie.

After introduction and using sonography and computed tomography over years magnetic resonance tomography is also being applied to clinical practice for various diseases. Considering the cost-benefit-risk new conceptions for the diagnostic strategy are necessary. With the presentation of the three supplementary and to some extent competitive cross sectional imaging procedures the diagnostic possibilities in space occupying processes of adrenals, kidneys, liver, and pancreas are discussed.

[Diagnosis of the aortocoronary bypass--a comparison of MRT and CT]. / Diagnostik aortokoronarer Bypässe--Ein Vergleich von MRT und CT.

Complaints of angina pectoris after aortocoronary bypass surgery can be due to the obturation of one or more bypasses. The aim of our study was the evaluation of magnetic resonance tomography for the investigation of bypass patency in comparison with computed tomography. We investigated 18 patients. 33 of 35 bypasses were safely detectable with spin-echo techniques and 32 with fast-scan-techniques and presentation in cine-mode. 25 of 33 bypasses were identified as open with the SE-technique, 27 of 32 with the "fast" technique. No safe decision was possible for 4 bypasses with SE-technique and for 1 bypass with the "fast" technique. The results are in good agreement with the reference investigation by CT. For the investigation of bypass patency with MRT neither x-rays nor contrast media are necessary. It is therefore recommended for patients with allergy to contrast media and cases with high radiation risk.

[Differential diagnosis by MRT of cavernous hemangiomas and malignant tumors of the liver--advantages of the multi-echo technic]. / MRT-Differentialdiagnose von kavernösen Hämangiomen und Malignomen der Leber--Vorteile der Multi-Echo-Technik.

With a retrospective analysis of images from 39 patients with histologically proven liver tumours we tried to determine the best MRT-parameter for detection of cavernous hemangioma (n = 19) and its differentiation from malignoma (metastases n = 17, HCC n = 5). The best differentiation was achieved with the contrast-to-noise ratio between lesion and liver in multi-echo-images with TR/TE = 2,000/210 ms and a definite limit with an accuracy of 84% for hemangioma and 91% for malignoma. The respective intensity ratios (lesion/liver) were 95% and 77%. T2-relation times and the T1- and T2-ratios were also calculated. In contrary to the literature we think that these parameters are not sufficiently discriminating.