[Magnetic resonance tomographic studies of pancreatic transplants]. / Kernspintomographische Untersuchungen von Pankreastransplantaten.

In a pilot study, a total of 16 recipients of a combined pancreatic-renal allograft were examined by means of magnetic resonance imaging. Two groups were formed according to the management of the exocrine secretion: In group I patients (n = 8) the pancreatic duct was occluded with an alcoholic prolamine solution, in group II (n = 8) pancreatic juice was diverted either into a Roux-loop of jejunum (IIa, n = 4) or into the urinary bladder (group IIb, n = 4). On the T1-weighted images no difference was found between both groups with respect to signal intensity. In contrast, on T2-weighted images of group IIb, which were in situ for a significantly shorter time, a higher signal intensity was noticed as compared with the other patients. From these findings it is concluded that graft fibrosis may occur even in pancreas transplants with diversion of the exocrine secretion.

Correlations between clinical and magnetic resonance imaging findings in multiple sclerosis.

40 patients with multiple sclerosis were investigated by magnetic resonance imaging (MRI) and computer tomography (CT). Additionally, cerebrospinal fluid (CSF) findings and evoked potentials (EPs; visual, brainstem) were evaluated. MRI findings were abnormal in 85% of the patients, whilst CT scan showed pathological changes in only 23%. The sensitivity for detecting lesions was significantly higher for MRI than CT. 86% of 23 patients with a duration of disease of more than 1 year had pathological MRI findings, and MRI was abnormal in 82% of 17 patients with a duration of symptoms up to 1 year. All patients with abnormal MRI had at least one other pathological laboratory finding. CT revealed only large lesions, and in patients with abnormal CT MRI visualized lesions more extensively. Additionally, brainstem lesions could be verified in 6 patients and spinal cord lesions in 3 cases. CSF was abnormal in 86%, and positive MRI findings occurred in 26 of 31 patients with abnormal CSF. Abnormalities of EPs were found in 76%, and MRI was positive in 24 of 33 patients with abnormal EPs.

Lumbar myelography with three-dimensional MR imaging.

A strongly T2*-weighted, three-dimensional (3D) PSIF (time-reversed FISP [fast imaging with steady-state precession]) gradient-echo magnetic resonance (MR) sequence, with postprocessing of the 3D data set with a maximum-intensity projection (MIP) algorithm, produced x-ray myelography-equivalent images. The method was tested in 10 healthy volunteers to optimize sequence parameters and was evaluated in 30 patients with proven lumbar disk disease. MIP myelograms, unlike two-dimensional MR images, could not show the pathologic disks themselves but clearly demonstrated the effect on the thecal sac, giving a clear overall view of its geometry and dimensions, especially when displayed in a cine loop. All 28 medial and mediolateral disk herniations could be visualized, whereas only three of eight intraforminal disk herniations were seen on MR myelograms.

Localization of pulmonary nodules before thoracoscopic surgery: value of percutaneous staining with methylene blue.

OBJECTIVE: Video-assisted thoracic surgery (VATS) is a new procedure that makes it possible to see the intrathoracic organs and to resect pulmonary nodules without thoracotomy. Preoperative localization of small nodules that may not be visible or palpable during VATS is desirable. Percutaneous placement of spring hookwires is widely used to localize pulmonary nodules before VATS; infrequently, the adjacent lung parenchyma is also stained with methylene blue. The purpose of this study was to evaluate the effectiveness of methylene blue staining of pulmonary nodules without placement of a hookwire. SUBJECTS AND METHODS: Fifteen pulmonary nodules in 15 patients were localized preoperatively under CT guidance by using techniques identical to those for CT-guided fine-needle aspiration of pulmonary nodules. Approximately 0.3 ml of methylene blue dye was injected into the nodule with a 22-gauge Chiba needle to stain the nodule, the needle pathway, and the visceral pleura. In two patients, a hookwire also was placed. All patients had solitary nodules in which transbronchial or transthoracic biopsy had been unsuccessful. The mean nodule diameter was 16 mm (range, 8-33 mm), and the mean distance to the nearest pleural surface was 10 mm (range, 0-21 mm). The localization procedure required a mean of 32 min (range, 18-47 min). RESULTS: All 15 nodules were stained successfully either in the center or within the margins; the two hookwires were found to be displaced. In three cases, pulmonary hemorrhage occurred as a complication of the percutaneous staining procedure: in one case, subsequent conversion to thoracotomy was necessary owing to pulmonary hemorrhage and additional pleural bleeding during VATS, which resulted from puncture with a trocar directly into the pleural adhesions. Anticipated complications, such as pneumothorax, occurred in five patients; one patient had pleuritic pain, but none required treatment. In one patient, conversion to thoracotomy was done so that an adenocarcinoma could be treated by means of a lobectomy. In two others, thoracotomy was done because of problems with technical devices. CONCLUSIONS: Percutaneous staining of pulmonary nodules is an accurate technique for localizing nodules before VATS. The procedure is easily and safely performed, and it obviates wire-related complications, such as severe pleuritic pain.

Radiodense concretions in maxillary sinus aspergillosis: pathogenesis and the role of CT densitometry.

The purpose of this study was to investigate by CT the origin of radiodense maxillary sinus concretions and whether CT densitometry is effective in the prediction of maxillary sinus aspergillosis and in the differentiation of the origin of these concretions. In a prospective study in 21 patients with radiodense maxillary sinus concretions detected by radiography, a preoperative CT study of the paranasal sinuses and the concretions was undertaken. Additional scans of the upper alveolar ridge were also performed. Radiological findings were compared with clinical symptoms and with CT findings, especially CT densitometry of the sinus concretions and dental root-filling material. All patients underwent a functional Caldwell-Luc operation; histological and microbiological examinations were performed. Fifteen of the 21 patients (71.4%) with radiodense concretions had a histological and microbiological diagnosis of sinus aspergillosis. The sinus concretions had CT densities higher than 2000 HU (Hounsfield units) in 15 patients and lower than 2000 HU in 6. fourteen of 15 patients (93.3%) with concretions having CT densities higher than 2000 HU had a postoperative diagnosis of maxillary sinus aspergillosis. The mean CT density of the sinus concretions in patients with maxillary sinus aspergillosis was 2868 HU (range 1870-3070 HU), and in patients without aspergillosis was 778 HU (range 228-2644 HU). The mean CT density of the dental root-filling material was 2866 HU (range 2156-3070 HU). Paranasal sinus CT with CT densitometry of a sinus concretion has a higher accuracy than standard radiography and clinical findings in the prediction of maxillary sinus aspergillosis (93.3% vs 71.4%). CT densitometry helps to confirm the dental origin of maxillary sinus concretions and to explain a possible dental pathogenesis of maxillary sinus aspergillosis.