Julien Struyven

Granulomatous prostatitis: a pitfall in MR imaging of prostatic carcinoma

Granulomatous prostatitis is an uncommon disease that can prostatic carcinoma on both digital rectal examination and transrectal ultrasound. Four patients who underwent magnetic resonance imaging of the prostate had a histological diagnosis of graanulomatous prostatitis; three of them had recent urinary tract infections. The other patient had an associated midline prostatic cyst and a focus of malignancy. T1-and T2-weighted spin-echo images were obtained in all cases. Peripheral zone lesions of decreased signal intensity, suggestive of carcinoma,were found in all four patients on T2-weighted images. Granulomatous prostatitis should be considered in the differential diagnosis of low signal intensity areas with prostatic magnetic resonance imaging.

Magnetic resonance imaging of the normal prostate at 1.5 T

Prostatic magnetic resonance images of 22 male volunteers less than 30 years old and with no known genito-urinary tract disease were obtained at 1.5 T. Normal anatomical features of the prostate were studied with spin-echo techniques. Different zones of the normal gland are shown by T2-weighted images: the anterior fibromuscular fascia, the central prostate, the peripheral prostate and the periurethral zone can be differentiated. The normal prostate gland is shown on T1-weighted images as a homogeneous appearance. It is important to recognize the normal zonal anatomy of the prostate since prostatic disorders arise in different anatomical zones.

Non-obstructive kidney transplant dysfunction: magnetic resonance evaluation

The value of magnetic resonance imaging in the differential diagnosis of non-obstructive dysfunction of renal allografts was studied in a series of 58 examinations at 0.5 T. Four parameters were evaluated: the corticomedullary differentiation; the relative thickness of the cortex; the evolution, with echo number, of the relative signal intensities of kidney parenchyma and adjacent fatty tissue on images generated by a long time to repeat multiecho sequence; and the proximal vascularization. The loss of corticomedullary differentiation is the major finding in acute rejection, but it is not specific as it is also observed in chronic rejection and in the much rarer acute glomerulonephritis. Thickening of the cortex is helpful for the detection of rejected transplants with visible corticomedullary delineation (26% of the cases). Uncomplicated acute tubular necrosis appears as a normal transplant.

Conventional and High-Resolution CT in Diagnosis of Occupational Lung Diseases: A Comparative Study — Preliminary Results

Twenty four asbestos and silica-exposed individuals were evaluated by means of conventional computed tomography (CT) and high-resolution computed tomography (HRCT). The aspects of asbestosis and silicosis and the diagnostic value of both methods were compared. The accuracy of each method was evaluated for the following abnormalities: nodules, masses, curvilinear subpleural lines, thickened interlobular lines, irregular interfaces, honeycombing, subpleural dependent density, parenchymal bands, ground-glass opacities, emphysema, subpleural blebs, rounded atelectasis, segmental or sub-segmental atelectasis, and hyaline and calcified pleural plaques. The diagnostic value of each technique is also estimated. HRCT is much more accurate in detecting curvilinear subpleural lines, thickened interlobular lines, irregular interfaces, honeycombing, ground-glass opacities and subpleural blebs. Conventional CT is dramatically more reliable for detection of small nodules. For the other abnormalities, our study was too limited by the relatively small number of cases to permit a definitive conclusion. We concluded on the basis of the preliminary report that both conventional and high-resolution computed tomography should be used in the examination of patient with occupational chest diseases.

Non-Obstructive Kidney Transplant Dysfunction: Magnetic Resonance Evaluation

The value of magnetic resonance imaging in the differential diagnosis of non-obstructive dysfunction of renal allografts was studied in a series of 58 examinations at 0.5 T. Four parameters were evaluated: the corticomedullary differentiation; the relative thickness of the cortex; the evolution, with echo number, of the relative signal intensities of kidney parenchyma and adjacent fatty tissue on images generated by a long time to repeat multiecho sequence; and the proximal vascularization. The loss of corticomedullary differentiation is the major finding in acute rejection, but it is not specific as it is also observed in chronic rejection and in the much rarer acute glomerulonephritis. Thickening of the cortex is helpful for the detection of rejected transplants with visible corticomedullary delineation (26% of the cases). Uncomplicated acute tubular necrosis appears as a normal transplant. New immunosuppressive medications, especially cyclo- sporin, have improved the results of kidney transplanta- tion, but they have also added to the difficulty of monitoring the post-transplantation course: cyclosporin nephrotoxicity must now be added to acute tubular necrosis (ATN) and rejection as causes of graft dysfunction. Moreover, cyclosporin decreases the clinical and functional manifestations of acute rejection. Radionuclide scintigraphy and sonography are estab- lished non-invasive modalities in the evaluation of post- transplant renal failure. Sonography is clearly the ideal technique for recognizing urinary obstruction. How- ever, both sonography and scintigraphy lack sensitivity and specificity in the early detection of acute rejection. Experience with magnetic resonance imaging (MRI) is still limited, and the present study was undertaken to assess its usefulness in the evaluation of kidney transplant patients with non-obstructive renal dys- function. Materials and methods Technique Magnetic resonance examinations were performed on a 1.5 T superconductive system (Philips SI5 Gyroscan), operating at 0.5 T. A surface coil was used for signal detection and the regular body coil for spin excitation. Both coils were electronically decoupled (Boskamp, 1985). During initial studies, a rectangular surface coil was used; this was subsequently replaced by a sandwich coil that provided good magnetic coupling with both walls of the hemipelvis. Although the prone position generates less movement artefact, patients were positioned supine, as this position proved to be better