Description and technical pitfalls of a hepatoma model and of intra-arterial injection of radiolabelled lipiodol in the rat

Intra-arterial metabolic radiotherapy (using lipiodol labelled with iodine-131 or rhenium-188) is a therapeutic approach that can be used for the treatment of hepatocellular carcinomas (HCC). We propose a detailed description of the tumoral model using the N1-S1 cell line as well as a technique for intra-arterial injection of radiolabelled lipiodol in order to undertake preclinical studies necessary for the evaluation of a new molecule. We also report the principal technical pitfalls that were faced. The speed of injection of the tumoral cells is a key factor in the tumoral induction since slow injections lead to a tumoral induction rate of 36.3% compared with 76.6% ( P < 0.01) when using very slow injections. This parameter should thus be controlled carefully during the subcapsular injection of the tumoral cells. In addition, when injecting radiolabelled lipiodol, anaesthesia should not be performed with isoflurane since this leads to a reduction in tumoral uptake. Indeed, we found a 'tumour/healthy liver' uptake ratio of only 2.1 ± 0.7 with isoflurane as against 4.4 ± 2.6 ( P < 0.05) when anaesthesia was carried out by intraperitoneal injection of ketamine. Lastly, we show that the tumour size has an influence on the tumoral uptake of radiolabelled lipiodol; therefore, this parameter must also be carefully controlled.

[Conventional and diffusion magnetic resonance imaging in the acute phase of severe traumatic brain injury]

Neuro-imaging is essential for the initial evaluation and subsequent control in the acute stage of severe head injury. In these indications tomodensitometry (TDM) has a pivotal role. Despite the well recognized contribution of magnetic resonance imaging (MRI) to the investigation of most of acute neurological pathologies, MRI is not still a routine procedure for the initial investigation of patients with acute head injury. The superiority of morphological and functional MRI on TDM in this indication is discussed.

Improving the detection of low concentration metabolites in magnetic resonance spectroscopy by digital filtering

In vivo detection and quantitation of metabolites is often limited by their low concentration. As far as magnetic resonance spectroscopy (MRS) is concerned, detection and quantitation can be significantly improved by reduction of the observed spectral width (SW). The reduction is limited to the spreading of resonances in the bandwidth unless high performance digital filters are used. Indeed, these filters avoid the folding of unwanted resonances such as water peak into the main frequency spectrum and therefore allow reduction of the spectral width to its optimal value. These filters are now available on most MRS systems but their use is not common even if, as we show in the particular case of proton MRS, a significant increase in signal-to-noise ratio (two-fold factor for SW reduction from 5000 Hz to 1351 Hz) can be achieved. This signal-to-noise improvement allows better quantitation accuracy.

Angiomagnetic resonance imaging of iliofemorocaval venous thrombosis

Although magnetic resonance imaging has been proposed for the diagnosis of deep venous thrombosis (DVT), its role in diagnostic strategy remains to be defined. We compared prospectively magnetic resonance angiography (MRA) with two-dimensional time-of-flight with contrast venography (CV) and colour duplex sonography (CDS) in 25 patients with DVT of the pelvis confirmed by CV. All patients were examined by CV (gold standard) and MRA and 17 by CDS. These studies were compared for DVT diagnosis in the pelvis and inferior vena cava and analysis of thrombotic spread. MRA was positive in 25 patients whose DVT was diagnosed by CV (100% sensitivity). MRA sensitivity and negative predictive value were 100%, specificity 98.5% and positive predictive value 97.5% for the diagnosis of thrombosis at each anatomic level. There were discrepancies between MRA and CV (2 false-positive results for 2 venous segments) and between CDS and CV (2 false-positive and 3 false-negative results). CV was uninterpretable for 8.8% of segments and CDS was often technically limited to the pelvic level, whereas all venous segments explored were analysable in MRA. MRA gave excellent results for positive diagnosis and DVT spread. MRA is a potentially valuable technique for assessing iliofemorocaval venous thrombosis.

Relationship between fat intake and glomerular filtration rate in normotensive insulin-dependent diabetic patients

Glomerular hyperfiltration is a candidate marker for diabetic nephropathy in insulin-dependent diabetic patients since it can reflect elevated glomerular capillary pressure, a cause of glomerulosclerosis. We studied the potential contribution of several dietary components to glomerular hyperfiltration during a cross-sectional study of 110 consecutive normotensive, non-proteinuric insulin-dependent patients with respect to glomerular filtration rate (GFR) and food intake. GFR was measured using the 51Cr-EDTA plasma disappearance technique. Glomerular hyperfiltration was defined as GFR > 137 ml.min-1 1.73 m-2 (mean +2 SD of age-matched healthy controls). Food intake was recorded with a computer-assisted programme. Thirteen patients displaying glomerular hyperfiltration ingested more protein (1.60 +/- 37 vs 1.38 +/- 0.34 g.kg-1 body weight.day-1; p = 0.032) and more fat (1.70 +/- 0.54 vs 1.39 +/- 0.44 g.kg-1 body weight.day-1; p = 0.022) than other subjects, although their total energy intakes were similar. Univariate regression analysis showed that GFR was positively related to both protein (r = 0.28; p = 0.003) and fat (r = 0.25; p = 0.007) intakes and negatively related to age (r = -0.29; p = 0.002). Stepwise multivariate regression analysis indicated 2 independent determinants for GFR: age (F = 15.26) and fat intake (F = 13.15). Excess fat intake may contribute to glomerular hyperfiltration in insulin-dependent diabetes.

[Thallium 201 myocardial scintigraphy and left branch block. Comparative value of exercise test and dipyridamole test]

Stress Thallium 201 myocardial scintigraphy in patients with left bundle branch block often shows reversible septal perfusion defects even in the absence of coronary artery disease. This phenomenon seems more common when the patients have tachycardia. With the working hypothesis that dipyridamole stress testing, which does not greatly increase the heart rate, would be more appropriate than exercise stress testing to unmask coronary artery disease in this condition, the authors compared the results of two Thallium 201 scintigraphies performed after exercise and then after dipyridamole under the same conditions three weeks later, in 67 patients with complete left bundle branch block. Scintigraphy showed one or more reversible perfusion defects in 64/67 patients after exercise but only 32/67 patients after dipyridamole (p < 0.001). There was poor uptake in the septal region in 59 patients (88%) after exercise and in 25 patients (37%) after dipyridamole (p < 0.001). The specificity was evaluated in 23 patients estimated to have no coronary artery disease. If only unequi vocal perfusion defects were considered, the specificity after dipyridamole was higher than that after exercise, increasing from: 35% to 83% for septal defects (p < 0.01); 65% to 96% for anterior wall defects (p < 0.05); 61% to 87% for inferior wall defects (p < 0.05); 57% to 91% for apical defects (p < 0.01); 17% to 83% overall (p < 0.001). Lower values but with a comparable difference were observed when all forms of hypofixation (even minimal) were taken into account.(ABSTRACT TRUNCATED AT 250 WORDS)

Glomerular hyperfiltration in type I, type II, and secondary diabetes

Glomerular hyperfiltration, a risk factor for diabetic nephropathy, has been reported in type I insulin-dependent diabetics, but it is not clear if it occurs in other types of diabetes. To ascertain the prevalence of glomerular hyperfiltration in various types of diabetes, we measured glomerular filtration rate (GFR) in 158 diabetics (91 type I, 36 type II without insulin treatment, 20 type II with insulin treatment, and 11 subjects with diabetes secondary to chronic pancreatitis), and classified them as hyper-, normo-, or hypofiltration according to values measured in 36 age-match controls. After elimination of subjects with overt renal disease or hypertension, glomerular hyperfiltration was detected in 35% of the type I diabetics, 32% of the type II diabetics without insulin treatment, one subject with chronic pancreatitis, and one type II diabetics with insulin treatment. Glomerular hyperfiltration was associated with high blood glucose in type I, insulin-dependent diabetics, and with a high apolipoprotein B/A1 ratio in type II, non-insulin-dependent diabetics without insulin treatment. In all subjects with glomerular hyperfiltration, GFR values and urinary albumin excretion were positively related (r = 0.33; n = 34; p = 0.05). Glomerular hyperfiltration is detectable among all types of diabetics.

[Dissociation of hypotensive and renal hemodynamic effects of an angiotensin converting enzyme inhibitor in insulin-dependent diabetic patients with incipient nephropathy]

The mechanism of action of angiotensin converting enzyme (ACE) inhibitors on urinary albumin excretion (UAE) in diabetics is controversial. In order to dissociate the hypotensive and intrarenal effects, 16 insulin-dependant diabetics with permanent microalbuminuria (30-300 mg/24 h) without hypertension were given Ramipril, a long acting ACE inhibitor, at hypotensive (treatment A 5 mg/day; N = 8) and at sub-hypotensive doses (treatment B, 1.25 mg/day; N = 8) over a 6 week period in parallel double-blind study. Blood pressure, UAE, glomerular filtration renal blood flow (continuous 125I-Iodothalamate + 131I-Hippurate infusion) and converting enzyme activity (Liebermann's method), before and after treatment. In treatment group A, the blood pressure fell from 133 +/- 5/79 +/- 4 (mean +/- SE) to 125 +/- 4/77 +/- 2 mmHg (p less than 0.05 for systolic blood pressure) whereas it remained stable in treatment group B (132 +/- 7/79 +/- 4 to 128 +/- 5/80 +/- 4 mmHg). The UAE decreased in both groups: group A from an average of 74 (40-198) to 47 (5-202) mg/24 h (p = 0.07; group B, from an average of 77 (50-136) to 19 (15-120) mg/24 h (p less than 0.005), as did ACE activity: group A from 332 +/- 44 to 163 +/- 33 iu/l (p less than 0.004), group B from 423 +/- 39 to 191 +/- 28 iu/l (p less than 10-4).(ABSTRACT TRUNCATED AT 250 WORDS)

[Diagnosis of chronic coronary failure by clinical aspects, ECG and myocardial scintigraphy after infusion of isoprenaline. Comparison with coronarography]

The purpose of this study was to assess the ability of isoproterenol (IPNA) to provoke chest pain, electrocardiographic (ECG) changes and transient defects on thallium 201 myocardial scintigraphy for coronary artery disease (CAD) diagnosis. Thirty patients without prior myocardial infarction who underwent coronary angiography were included. Significant stenosis was found in 15 and absent in the other 15. The most relevant clinical and ECG data were observed in the few minutes that followed IPNA perfusion: 1) angina pectoris occurred in ten patients of whom eight had CAD (sensitivity: 53 p. cent + 13 p. cent; specificity: 87 p. cent + 9 p. cent); 2) ST segment depression was observed in 11 CAD and 3 non-CAD patients (sensitivity: 73 p. cent + 11 p. cent; specificity: 30 p. cent + 10 p. cent); 3) reversible perfusion defects on planar myocardial thallium 201 scintigrams occurred in 16 patients of whom 13 had CAD. Thallium scintigraphy sensitivity was 87 p. cent + 9 p. cent and specificity was 80 p. cent + 10 p. cent. The combined interpretation and stochastic sequential analysis of two or three presumed independent criteria increased significantly the diagnostic value of the test. We conclude that the isoproterenol test is a safe and reliable method to provoke myocardial ischemia with clinical, ECG and myocardial scintigraphic expression. It has an information content nearly identical to exercise stress test for CAD detection. Because it allows a three step sequential probability analysis, the diagnosis is more reliable than with other pharmacological tests which apply only to scintigraphy.

Thyroid uptake of MIBG in Sipple's syndrome

The use of the adrenomedullary tracer metaiodobenzylguanidine (MIBG) in the localization of medullary carcinoma of the thyroid (MCT) is based on the embryologic relationship of the APUD cell series. The authors report the results obtained in six patients with MCT: two had Sipple's syndrome and four sporadic forms of the disease. MIBG uptake by the CMT was observed in both cases of Sipple's syndrome and in only one of the other cases. Scintigraphic detection seems to depend on the clinical features, the size of the tumour and also on the part played by its secretory function. MCT would thus appear to be more frequently visualized by MIBG in cases of Sipple's syndrome than in sporadic cases. The procedure therefore seems useful in the diagnosis, follow up and even in the treatment of MCT.

[Athlete's pubic pain syndrome or "pubialgia". Comparison of radiological and scintigraphic findings]

The pubic pain syndrome in athlete's results from two principal mechanisms: muscle insertion tendinitis or dynamic arthropathy of the pubis. Classification of these two entities is established by comparing radiological and scintigraphic findings.