Walter Heindel

Age- and sex-specific differences in the 1H-spectrum of vertebral bone marrow.

Correct interpretation of 1H magnetic resonance (MR) studies of the red vertebral bone marrow in patients with disorders of the hematopoietic system requires knowledge of the dependence of the proton spectrum on age and sex. Infiltration of malignant cells causes a decreased red bone marrow fat signal, which is reversed upon successful treatment. The aim of this study was to establish a database of normal water/fat relations from a large group of volunteers. In all, 154 healthy volunteers from 11 to 95 years of age were examined using a 1.5‐T MR system (ACS‐NT, Philips). A volume of 2–8 ml in the center of a normal vertebral body was selected for spectroscopy using the PRESS sequence without water suppression (TR/TE 2 sec/40 msec). Signal intensities and T2 times of lipid and water resonances were determined. The relative fat signal intensity was calculated corrected for T2 relaxation. The relative proportion of protons in the fat signal increases with age from 24% in the age group 11–20 years to 54% in the group ≥61 years. The proportion of fat in the vertebral bone marrow in female subjects is less than that in male subjects in the same age group (statistically significant at P ≤ 0.01). In the central age group between 31 and 50 years, the difference is largest, at 12%; in the youngest and oldest age group this difference is small. T2 times are neither age nor sex dependent. J. Magn. Reson. Imaging 2001;13:263–268.

CT and MR imaging in primary cerebral non-Hodgkin's lymphoma

Purpose: to determine the morphological appearance and topographical distribution of primary cerebral non-Hodgkins lymphoma (NHL). Material and Methods: CT and MR examinations of 68 patients with primary cerebral NHL were analyzed. the NHLs were classified by the Kiel classification and im-munohistological data, as centroblastic (25), immunoblastic (24), lymphoblastic (5), Burkitt (1), non-subclassifiable type B (11), and T-cell lymphoma (2). Results: Centroblastic lymphomas tended to predominate in the parietal lobe (56.5%) and the corpus callosum (59.1%) while immunoblastic lymphomas were mainly distributed in the frontal lobe (52.8%). About 2/3 of all NHLs showed a multi-focal occurrence. Important for differential diagnosis, ventricular involvement was proved in 83.3% of these cases. in the remaining 26 patients with a solitary lymphoma, a periventricular location could be detected in only 8 cases. Central necroses were frequent in HIV-positive patients (7/11, 63.6%) but rare in the HIV-negative patients (9/57,15.8%). on T2-weighted SE MR images, 8/11 centroblastic lymphomas gave a signal that was isointense with, or lower than, that of the contralateral white matter, while 8/10 immunoblastic lymphomas gave a higher signal. Conclusion: the radiological finding of multifocal brain lesions with ventricular involvement is relatively specific for primary cerebral NHL. However, subclassification on the basis of the CT or MR imaging results is not yet possible.

Iodixanol vs iopamidol in intravenous DSA of the abdominal aorta and lower extremity arteries: a comparative phase-III trial.

Iodixanol (visipaque, 320 mgI/ml) was compared with iopamidol (Solutrast, 370 mfI/ml) in a double-blind, randomized, parallel group, intravenous DSA phase-III trial for evaluation of safety and efficacy. A total of 117 patients received iodixanol (n = 60) or iopamidol (n = 57). Diagnostic efficacy was evaluated using categoric and visual analogue scales. Discomfort and adverse evenets were recorded. A total of 39 patients collected urine up to 72 h after the examination for analysis. Diagnostic efficacy and radiographic density were similar in both groups. Discomfort was milder with iodixanol. The difference between the frequency of adverse events between both groups (iodixanol = 7, iopamidol = 2) was without statistical significance. Creatinine clearance was slightly more affected by iodixanol, whereas the increase in renal excretion ofN-acetyl-beta-glucosaminidase (NAG) in the first 24 h collection period after the examination was significantly higher (p < 0.01) with iopamidol. Iodixanol was of equal diagnostic efficacy compared with iopamidol despite its reduced iodine content. Both contrast media are well suited for IV DSA.

Proton magnetic resonance spectroscopy reflects metabolic decompensation in maple syrup urine disease

Using localized proton magnetic resonance spectroscopy (1H-MRS), accumulation of branchedchain amino acids (BCAA) and their corresponding 2-oxo acids (BCOA) could be non-invasively demonstrated in the brain of a 9-year-old girl suffering from classical maple syrup urine disease. During acute metabolic decompensation, the compounds caused a signal at a chemical shift of 0.9 ppm which was assigned by in vitro experiments. The brain tissue concentration of the sum of BCAA and BCOA could be estimated as 0.9 mmol/l. Localized1H-MRS of the brain appears to be suitable for examining patients suffering from maple syrup urine disease in different metabolic states.

Diagnosis of left ventricular thrombi by magnetic resonance imaging and comparison with angiocardiography, computed tomography and echocardiography

Abstract Left ventricular (LV) thrombi are common in patients with acute and healed anterior myocardial infarction. Although the reported incidence of clinically diagnosed embolism varies widely,1–3 diagnosis of thrombus seems to carry an increased risk for this potentially life-threatening complication. It is not entirely clear whether long-term anticoagulation can reduce the embolism rate in patients with chronic aneurysms with an acceptable risk of bleeding. However, it is widely assumed that this is so; thus, the diagnosis of LV thrombus has far-reaching consequences. It is difficult to diagnose LV thrombus using currently available imaging techniques. LV angiography carries the risk of precipitating systemic emboli and has a low sensitivity in most reported studies.4 Echocardiography has been reported to be fraught with false-positive results.5,6 Indium-111 platelet scintigraphy reflects thrombus activity but has suboptimal sensitivity, especially for small thrombi.7 More recently, computed tomography (CT)8 and magnetic resonance imaging (MRI)9,10 have shown encouraging results in the detection of LV thrombi. However, the diagnostic accuracy of MRI has not been evaluated with independent confirmation by surgery or autopsy. This study describes the sensitivity and specificity of MRI in the diagnosis of LV thrombi in patients with LV aneurysms undergoing surgical aneurysmectomy, and compares the results with those of angiography, 2-dimensional echocardiography and CT performed in the same patients.

CT-guided lumbar sympathectomy : Results and analysis of factors influencing the outcome

AbstractPurpose: To prospectively analyze the effectiveness of computed tomography-guided percutaneous lumbar sympathectomy (CTLS) in patients with peripheral arterial occlusive disease in relation to angiographic findings and vascular risk factors. Methods: Eighty-three patients were treated by CTLS. After clinical evaluation of the risk profile and diagnostic intraarterial digital subtraction arteriography, 14 patients underwent unilateral, and 69 bilateral one-level treatment. Follow-up studies took place on the day following the intervention, after 3 weeks, and after 3 months. Results: A total of 152 interventions were performed in 83 patients. After 3 months, clinical examination of 54 patients (5 patients had died, 24 were lost to follow-up) revealed improvement in 46% (25/54), no change in 39% (21/54), and worsening (amputation) in 15% (8/54). There was no significant statistical correlation among any of the analyzed factors (diabetes mellitus, arterial hypertension, smoking, hyperlipidemia, obesity, hyperuricemia, number of risk factors, ankle-arm index, and angiography score) and the outcome after CTLS. Three major complications occurred: one diabetic patient developed a retroperitoneal abscess 2 weeks after CTLS, and in two other patients ureteral strictures were detected 3 months and 2 years after CTLS, respectively. Conclusion: As no predictive criteria for clinical improvement in an individual patient could be identified, CTLS, as a safe procedure, should be employed on a large scale in patients who are unsuitable for treatment by angioplasty or revascularization.

INFLUENCE OF THE HEPATOBILIARY CONTRAST AGENT MANGAFODIPIR TRISODIUM (MN-DPDP) ON THE IMAGING PROPERTIES OF ABDOMINAL ORGANS

To assess the influence of Mangafodipir Trisodium on the imaging properties of abdominal organs when using T1-weighted gradient-echo (GE) and T2-weighted turbo spin-echo (TSE) sequences, thirty patients with focal lesions in the liver were examined at a field strength of 1.5 T before and after intravenous administration of Mangafodipir Trisodium (dose: 5 micromol/kg of body weight). Administration of Mangafodipir Trisodium led to a significant increase in the signal intensity of the liver tissue (p < 0.001), the spleen (p < 0.01), the pancreas (p < 0.001), and the kidneys (p < 0.001) in the T1-weighted GE sequence, while there was no relevant enhancement in fatty tissue and the musculature. In the T2-weighted turbo spin-echo sequence, there was no relevant change in the signal following administration of a contrast agent. The contrast-to-noise ratio (C/N) between the lesions and the liver tissue increased significantly in the post-contrast T1-weighted GE sequence (p < 0.001), while there was no change in the contrast-to-noise ratio in the post-contrast T2-weighted turbo spin-echo sequence. The contrast-to-noise ratio of the plain T2-weighted TSE sequence was significantly higher than that in the post-contrast T1-weighted GE sequence (p < 0.001). Although Mangafodipir Trisodium was primarily developed as a hepatobiliary contrast agent for demonstration and differentiation of liver lesions, it also affects the signal levels in the pancreas, spleen, and kidneys in the T1-weighted image. Awareness of this effect on the extrahepatic tissue makes it easier to interpret pathological findings in magnetic resonance imaging (MRI) of the abdomen.

Transbrachial thrombolysis, PTA and stenting in the lower extremities

We present an analysis of 37 interventions in the arteries of the lower limbs via a transbrachial arterial approach. Twenty-six patients (42–79 years) underwent 37 interventional procedures in the lower extremities (iliac n = 6, iliac + femoro-popliteal n = 1, femoro-popliteal n = 30) with a vascular approach via the brachial artery (33 left sided, 4 right sided, introducer sheath 4–7 F). The transbrachial approach was chosen to avoid puncture of femoral bypass graft material. Technical success could be achieved in 11/13 thrombolyses, 8/9 PTAs, 7/10 combinations of thrombolysis and percutaneous transluminar angioplasty (PTA) and in the placement of two stents. One patient suffered from periprocedural severe re-thrombosis due to insufficient anticoagulation during fibrinolysis, and twice thrombolysis was incomplete. One puncture-related false aneurysm of the brachial artery had to be corrected surgically. One transient ischemic attack (TIA) and four minor complications occurred. Transbrachial vascular approach for arterial interventions in iliac and femoro-popliteal pathologies is a reasonable alternative to the transaxillary access if transfemoral puncture has to be avoided. The technical success rate is comparable with the results of the transaxillary and transfemoral approach. To minimize, at least theoretically, the risk of cerebral complications, the left- sided approach should be preferred and intravenous heparin should be administered routinely.

Somatosensory evoked potentials: a simple neurophysiological monitoring technique in supra-aortal balloon test occlusions.

Abstract. The aim of this study was to evaluate somatosensory evoked potentials (SEP) as a simple neurophysiological monitoring method in supra-aortal balloon test occlusions (BTO). The 13 patients examined had carcinoma of the larynx (n = 6), nasopharyngeal malignancy (n = 3), sphenoid meningioma (n = 2), mycotic aneurysm (n = 1), and a tumor of the carotid body (n = 1). Transfemoral balloon occlusion of the internal carotid artery was maintained for 30 min and monitored both clinically and by SEP. None of the 13 patients showed neurological deficits or pathological changes in the SEP. No thromboembolic complications occurred during BTO. In 11 cases the cervical vessels could be spared or reconstructed during surgery. No neurological symptoms occurred during the clinical follow-up. One patient died the day after BTO due to cardiac arrest. Neurophysiological monitoring of preoperative BTO using SEP is a technically simple method. A similar method has been shown to have a high sensitivity and reliability in carotid surgery.

Treatment of a ruptured anastomotic esophageal stricture following bougienage with a dacron-covered nitinol stent

A patient suffering from esophagorespiratory fistula after bougienage of a benign stricture at the site of the anastomosis between a jejunal interposition and the esophagus was referred for interventional treatment. A prototype nitinol stent centrally covered with Dacron was implanted under regional anesthesia and fluoroscopic guidance. The self-expanding prosthesis dilated the stenosis completely and closed the fistula, with consequent improvement in respiratory and nutritional status and thus the general quality of life. The patient was able to eat and drink normally until death 3 months later due to progression of his underlying malignant disease.