MR characteristics of prostatic carcinoma and benign prostatic hyperplasia at 1.5 T

Sixty-one patients with histologically proven disorders of the prostate [prostatic carcinoma (PC), 41; benign prostatic hyperplasia (BPH), 9; PC and BPH, 11] underwent magnetic resonance imaging at 1.5 T. Using single [spin echo (SE) 400/30] and dual (SE 1,600/30, 90) SE sequences, multislice contiguous scans were obtained in transverse, sagittal, and coronal planes through the prostate. In 27 patients (PC 14, BPH 6, PC and BPH 7) multiecho sequences with eight echoes (SE 1,600/30, 60, 90, 120, 150, 180, 210, 240) were acquired and T2 images were calculated in the planes with best depiction of circumscribed prostatic pathology. In these patients the Bhattacharyya coefficient, a quantitative criterion for the discrimination between normal and pathological tissue, derived by means of mathematical decision theory, was applied. This analysis showed the best discrimination between PC and normal prostate with echo time (TE) 90 and 120 ms [error rate (ER) for confusing these tissues 20-30%]. There was no significant difference between the signal intensities of PC and BPH at any parameter setting, but PC could be discriminated from the compressed peripheral glandular regions that often accompany BPH [minimal ER (20-30%) at TE 90 and 120 ms]. This distinction is of clinical value, since PC usually arises in the periphery of the prostate. Calculated T2 images did not show advantages for the detection of PC.     

A multicenter clinical trial of gadolite oral suspension as a contrast agent for MRI

The purpose of this study was to assess the effectiveness and safety of Gadolite Oral Suspension as a gastrointestinal (GI) contrast agent for MRI in a phase II and two phase III multicenter clinical trials. Gadolite was administered to 306 patients with known or suspected abdominal and/or pelvic disease. MRI with T1- and T2-weighted sequences was performed before and after ingestion. Efficacy was evaluated by having two masked readers rate the certainty of their MR diagnosis (0 = uncertain, 1 = probable, 2 = definite) on randomly presented pre- and post-Gadolite Oral Suspension enhanced images. Principal investigators also evaluated the images and established the final diagnosis. Vital signs, clinical chemistries, and adverse events were documented. Blood and urine samples were analyzed for gadolinium content to determine whether Gadolite Oral Suspension was absorbed systemically. Certainty in MR diagnosis increased significantly (P < .001) for both blinded readers between pre- and post-Gadolite images (.49–1.18 for reader 1; .46–1.53 for reader 2). Sensitivity, specificity, and accuracy also increased for both masked readers. No gadolinium was detected in blood or urine samples. There were no serious adverse events and no apparent drug-related trends in mean vital signs or laboratory values. Gadolite is a highly effective, safe, and well tolerated contrast agent for clinical use with MRI.     

Patterns of structural deterioration due to ischemia in Purkinje fibres and different layers of the working myocardium

Cellular and mitochondrial swelling are regarded as typical intra-ischemic alterations ("IIA"), contraction band lesions (CBL), in contrast, as products of post-ischemic reperfusion. The occurrence of both types of structural deterioration was investigated in Purkinje fibres and subendocardial and intramural working myocardium: initially after St. Thomas- or HTK cardioplegia, then during ensuing global ischemia up to the "practical limit of resuscitability", and following post-ischemic reperfusion. Generally, Purkinje fibres are not better preserved than neighbouring working myocardium. Comparing St. Thomas- and HTK cardioplegia, considerable quantitative, but not qualitative differences in the reaction patterns of different cell types or layers arise. Immediately after cardioplegia, CBL are completely lacking in both cell types. During ischemia, CBL occur occasionally in Purkinje fibres and seldom in subendocardial working myocardium, "IIA" predominate. During post-ischemic reperfusion "IIA" tend to reverse in all layers, whereas CBL are found to remain in the subendocardial cell types. In intramural layers, CBL occur only during reperfusion. Thus, we deduce that cardioplegia only modulates the severity of "IIA" and the frequency of CBL, but cannot abolish the particular sensitivity of subendocardial Purkinje fibres to global ischemia. Prerequisites for the development of irreversible CBL are on the one hand ischemic metabolic alterations and corresponding energy deficits, and, on the other hand, a supply of oxygen. The oxygen may be inadequately supplied via diffusion during ischemia or may be subsequently provided by reperfusion.     

Efficacy and safety of mangafodipir trisodium (MnDPDP) injection for hepatic MRI in adults: results of the U.S. Multicenter phase III clinical trials. Efficacy of early imaging

The efficacy of contrast-enhanced magnetic resonance imaging (MRI) for detecting and characterizing, or excluding, hepatic masses was assessed in 404 patients, following the intravenous administration of mangafodipir trisodium (MnDPDP) injection, a hepatic MRI contrast agent. An initial contrast-enhanced computed tomography (CT) examination was followed by unenhanced MRI, injection of MnDPDP (5 micromol/kg IV), and enhanced MRI at 15 minutes post injection. Agreement of the radiologic diagnoses with the patients' final diagnoses was higher for enhanced MRI and for the combined unenhanced and enhanced MRI evaluations than for unenhanced MRI alone or enhanced CT using the clinical diagnosis as the gold standard. Mangafodipir-enhanced MRI uniquely provided additional diagnostic information in 48% of the patients, and patient management was consequently altered in 6% of the patients. MnDPDP-enhanced MRI was comparable or superior to unenhanced MRI and enhanced CT for the detection, classification, and diagnosis of focal liver lesions in patients with known or suspected focal liver disease.     

Renal cortical calcification in syngeneic intact rats and those receiving an infrarenal thoracic aortic graft: possible etiological roles of endothelin, nitrate and minerals, and different preventive effects of long-term oral treatment with magnesium, citrate and alkali-containing preparations

Renal cortical nephrocalcinosis (C-NC) is a rare disorder of uncertain etiology. Using highly inbred (syngeneic) male Lewis rats, we describe the spontaneous occurrence of histologically detectable C-NC in sham operated control rats (Sham; n=12), its aggravation following grafting of the ascending thoracic aorta from a donor rat to the infrarenal aorta of a recipient (ATx; n=12), and differences in C-NC inhibition after 12 weeks of oral administration of magnesium (Mg), citrate and alkali. C-NC is characterized by Kossa-positive areas located in cells of the proximal tubule close to blood vessels and also, to a lesser extent, within glomeruli. After ATx there was vascular overproduction of endothelin (ET-1) but decreased production of nitrate; in renal cortical tissue there was an excess of calcium over Mg and phosphorus and oxalate over citrate. In plasma there was an increase in calcium and creatinine within the normal range. Calcification of tubular cells was eliminated by a preparation containing potassium, sodium and bases (from citrate degradation and bicarbonate) in addition to Mg. Less effective than the latter was Mg-potassium citrate and least effective, Mg citrate. The former treatment also normalized calcemia and urinary nitrate, but only incompletely suppressed ET-1 and had no significant effect on glomerular calcification or tissue and urinary oxalate. Urinary ET-1 excess appeared directly related to the cortical tissue calcium/Mg ratio, and urinary excretion of Mg, citrate and total protein appeared to be inversely related to the severity of C-NC. It was concluded that (1) the highly inbred rat is prone to precipitation of calcium phosphate in the renal cortex; (2) this type of C-NC occurs in close proximity to and within renal vascular tissue and is associated with an imbalance of vasoconstrictors and vasodilators of endothelial origin; (3) effective inhibition of C-NC can be achieved by an alkalinizing combination of Mg, potassium, sodium and citrate, underscoring its utility in the prophylaxis of pathological calcium phosphate deposition. The significance of these findings for the etiology and treatment of clinical disorders with renal and vascular calcification is uncertain and requires further investigation.     

Structural protection of the myocardial capillary endothelium by different forms of cardiac arrest and subsequent global ischemia at 5 degrees C.

BACKGROUND: In transplantation surgery sufficient myocardial protection achieved by cardioplegic cardiac arrest and deep hypothermia is a prerequisite for successful resumption of donor heart function. Intraischemic damage of the endothelium combined with capillary compression may lead to the "no-reflow phenomenon" during reperfusion, resulting in insufficient cardiac resuscibility. METHODS: We evaluated the endothelial ultrastructure after various common forms of cardiac arrest and subsequent ischemia in deep hypothermia. Canine hearts were arrested by aortic cross clamping and surface cooling with Tutofusin' (ACC) or by coronary perfusion with Custodiol (histidine tryptophane ketoglutarate, HTK solution), with University of Wisconsin solution (UW), or with St. Thomas' Hospital solution. After extirpation the hearts were incubated at 5 degrees C in the solution used for cardiac arrest. Myocardial samples were taken immediately after cardiac arrest and after 2h, 4h, 6h, and 10 h of global ischemia. The degree of structural damage was evaluated by a scoring system. Endothelial swelling was determined as the mean barrier thickness of the capillary endothelium. RESULTS: At all selected time points our results show that 1) after cardioplegia with St. Thomas' solution, the degree of endothelial cell swelling was higher than after aortic cross clamping; 2) using HTK or UW solution, the endothelial ultrastructure was better preserved than after aortic cross clamping or using St. Thomas' solution, whereby HTK was slightly better than UW; 3) using UW solution, endothelial cell swelling was a little (up to 10%) but significantly less than after HTK perfusion. CONCLUSIONS: With respect to the intraischemic structural preservation of endothelial cells, UW or HTK solution combined with deep hypothermia promises adequate protection, compared with other clinically used methods tested.