[A comparison of positive and negative enteral contrast media for the magnetic resonance tomography of the abdomen]. / Vergleich positiver und negativer enteraler Kontrastmittel für die magnetische Resonanztomographie des Abdomens.

Following oral administration of a buffered gadopentetate-dimeglumine solution (Magnevist enteral, 1 mmol/l, 6-17 ml/kg) T1-, proton-density- and T2-weighted spin-echo images of abdominal and retroperitoneal lesions were acquired (0.5 T). Gadopentetate is a signal-enhancing, positive MR contrast agent, intraluminal air served as a model of a signal-free, negative agent. In 21 patients contrast/noise ratios of gadopentetate and air versus lesions and fat were compared quantitatively (t-test). In T1- and T2-weighted images contrast/noise ratios of gadopentetate versus lesions were significantly higher than those of air. In proton-density images there was no significant difference. In T1- and proton-density images contrast/noise ratios of air versus abdominal fat were significantly higher than those of gadopentetate, in T2-weighted images gadopentetate had a significantly higher contrast/noise ratio than air. Signal-enhancing positive contrast agents seem advantageous over signal-free negative enteral MR contrast agents.

[Oral contrast media for the magnetic resonance tomography of the abdomen. A clinical trial of the tolerance for gadolinium-DTPA]. / Orale Kontrastmittel für die magnetische Resonanztomographie des Abdomens. Klinishce Prüfung der Verträglichkeit von Gadolinium-DTPA.

Safety and efficacy of gadopentetate-dimeglumine (Gd-DTPA) as a MR bowel contrast agent were determined in 133 patients with CT-proved abdominal and retroperitoneal mass lesions using a buffered formulation (1 mmol/l Gd-DTPA, 15 g/l mannitol, 25 mmol/l sodium-citrate, 6-17 ml/kg). Short-lived gastrointestinal side effects were noted in 32% of patients. Gd-DTPA provided uniform, hyperintense bowel labelling and contrast enhancement in the region of interest in 81% of patients. Among 78 patients with pre- and postcontrast images lesion delineation was improved in 62%. In 55 studies with postcontrast images only, Gd-DTPA proved useful in 65%. In 105 of 109 cases IV injection of scopolamine or glucagon eliminated image artifacts arising from peristalsis of opacified bowel. The authors conclude that Gd-DTPA is a safe and effective MR bowel contrast agent.

[Gadolinium-DTPA as an oral contrast medium for magnetic resonance tomography of the pancreas]. / Gadolinium-DTPA als orales Kontrastmittel für die magnetische Resonanztomographie des Pankreas.

52 patients with normal pancreas, pancreatitis and pancreatic tumors were examined by magnetic resonance imaging (Magnetom 0.5 T). Using T1-, proton density- and T2-weighted spin-echo sequences images were obtained before and after oral administration of Gadolinium-DTPA (Gd-DTPA, 1 mM, 15 g/l Mannit, 5-13 ml/kg). Gd-DTPA resulted in hyperintense labeling of small bowel in all sequences and improved visualization of pancreatic head, body and tail in 15, 14 and 7 of 27 patients with normal pancreas and in 17, 8 and 6 of 25 patients with diseased pancreas. Better delineation of pseudocysts and tumorous gut wall invasion were diagnostically profitable. With regard to motion artifact reduced MRI of the intestine using fast sequences Gd-DTPA may be a suitable oral contrast agent to improve the imaging of the pancreas.

[Meningeal metastasis of malignant melanoma]. / Meningeale Metastasierung maligner Melanome.

Two woman patients with malignant melanoma of the skin known from their case history and with acutely emerging neurological symptoms were examined both by CT and by MR tomography (both plain and with intravenous contrast medium). The radiologically derived suspicion of meningioma could not be confirmed by intraoperatively performed histological examination. In both cases the patients had meningeal melanoma metastases with low melanin content and without noticeable bleeding into the metastases. MR diagnosis is rendered difficult by the absence of paramagnetic substances typical of melanoma metastases. Hence, if the case history is known, it should be considered whether there is meningeal metastasising with atypical histology.

[Gadolinium-DTPA as an oral contrast medium in magnetic resonance tomography]. / Gadolinium-DTPA als orales Kontrastmittel in der Magnetischen Resonanz-Tomographie.

80 patients with tumorous or inflammatory abdominal diseases were investigated with the paramagnetic MRT contrast medium Gadolinium-DTPA (Gd-DTPA, 1 mM, 15 g/l mannitol, 6-16 ml per kg body weight) at 0.5 Tesla with T1-, proton density and T2-weighted SE- and gradient-echo sequences. 53 patients were investigated also before the contrast medium was given. Gd-DTPA showed hyperintense labelling of the intestinal loops that was detectable with all excitation sequences and was constant over all phases of the passage. In 35 of the 53 patients investigated before and after application of Gd-DTPA lesions were better imaged while diagnostic improvements, especially for smaller lesions, were achieved in 5 of 80 patients. One third of the patients reported slight meteorism and diarrhoea after the mannitol-containing suspension.

[Bladder tumors--Magnevist-assisted magnetic resonance tomography]. / Blasentumoren--Magnevist unterstützte Magnetresonanztomographie.

Magnetic resonance imaging (MRI, Magnetom 0.5 Tesla) using a high-resolution surface coil was performed on 10 healthy volunteers, 16 patients with bladder tumours, 2 patients with cystitis and 15 patients with bladder tumours and cystitis. Lesion delineation versus urine, bladder wall and surrounding organs was evaluated in plain and contrast-enhanced (IV Magnevist, 0.1 mmol/kg) T1-weighted, plain proton-density and T2-weighted spin-echo images. Surface-coil MRI proved very sensitive since all lesions were found in plain scans. Cystitis and 27 of 31 tumours exhibited contrast enhancement, however, differentiation of tumours and cystic lesions was not improved. Plain T2 and contrast-enhanced T1-weighted images demonstrated bladder wall disruption and perivesical tumour spread with equal sensitivity. Post-contrast images permitted unequivocal visualisation of perivesical tumour spread in surrounding peritoneal fat. The authors conclude that T2-weighted imaging may be restricted to non-enhancing bladder tumours thus significantly reducing imaging time.

Gadopentetate dimeglumine as a bowel contrast agent: safety and efficacy.

To determine the safety and efficacy of gadopentetate dimeglumine as a bowel contrast agent, magnetic resonance (MR) imaging (0.5 T) was performed with a formulation of gadopentetate dimeglumine (1.0 mmol/L of gadopentetate dimeglumine, 15 g/L of mannitol, 6-17 mL/kg) in 133 patients with intraabdominal mass lesions. Mostly short-lived gastrointestinal side effects were noted in 32% of patients. Gadopentetate dimeglumine provided uniform hyperintense marking of the bowel and contrast enhancement in the region of interest in 81% of patients. Among 78 patients with images obtained both before and after administration of contrast material, post-contrast improvement of lesion delineation was found in 62%. Among 55 patients with only postcontrast images, gadopentetate dimeglumine proved useful in 65%. Intravenous injection of scopolamine or glucagon effectively eliminated "ghost" images of the opacified bowel in 105 of 109 cases. The authors conclude that gadopentetate dimeglumine is a safe and effective bowel contrast agent for MR imaging.