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The purpose of this article is to review the diagnostic work-up of renal failure, acute or chronic. The role of the radiologist is to exclude the presence of a curable etiology such as urinary tract obstruction or vascular thrombosis. Renal ultrasound with Doppler imaging is the imaging modality of choice for this indication, and the use of a contrast agent is useful to evaluate renal perfusion. Non-contrast CT remains valuable for the diagnosis of some urinary tract pathologies. Finally, MRI is the most comprehensive imaging modality for the evaluation of the urinary tract, but performed as a second line modality mainly for practical reasons but also due to the non-negligible risk of nephrogenic systemic fibrosis secondary to the intravenous administration of gadolinium based contrast agent., (Copyright © 2011. Published by Elsevier Masson SAS.)

MRI can assess local and locoregional spread of a newly diagnosed prostate cancer by detecting extracapsular extension (ECE), seminal vesicle invasion (SVI) and lymph node invasion. Endorectal MRI remains the only accurate means to assess local extension. Pelvic MRI with surface coils and the use of superparamagnetic particules provide the sensitivity and the specificity which have never been obtained by the sole measurement of node size of the lymphatic chains draining the prostate gland. With the endorectal coil, only direct signs of extracapsular extension have been maintained and indirect signs have been discarded, giving their too low specificity. Early SVI can only be consistently detected if result of TRUS guided biopsies show involvement of the prostate base. With the pelvic phased array coil, superparamagnetic particules show that metastatic lymph nodes have a specific MR signal which can be detected in normal size nodes. Indications of imaging relies on results of parametrers available before MR imaging. More important than PSA level and Gleason score on biopsies is the so called quantitative histology, represented by the number of sextants involved by tumor and the amount of cancer (measured in mm of tumor) present on biopsies which determine a risk of extraprostatic spread. Of the risk of extraprostatic spread depends indication of MR, which is most probably unnecessary in patients at low risk (<20%) of extraprostatic extension.

We report a case of benign colonic tubular adenoma arising in a 36-year-old female at the site of ureterosigmoidostomy performed 25 years before. The tumor was revealed by recurrent episodes of pyelonephritis; hydronephrosis was present. On colonic enema, the tumor appeared lobulated, 4 cm in diameter. CT scan showed a multiloculated mass, which enhanced after injection. Pathology revealed a tubular adenoma of the colon with cystic dilatation of glandular structures. The role of imaging studies in the follow-up of patients after ureterosigmoidostomy is discussed.

An unusual case of spontaneous intraperitoneal rupture of the ureter was observed in adult with acute renal pain. Diagnosis was best established with CT rather than intravenous urography. CT demonstrated ureteral leakage with the contrast medium extravasating into the peritoneal cavity. The patient was initially managed successfully by endourology. Secondary stenosis of the ureter required surgery for partial resection of the distal ureter.

We report a case of subacute bowel obstruction due to a compression of the rectosigmoid junction by a chronically distended bladder, occurring in a 91-year-old male suffering from a long-standing diabetes mellitus and a prostatic adenoma. Radiographic, water-soluble contrast enema and pelvic CT features are reported.

We know that the contrast of MR images can be better than that of CT scans. In the spin echo mode, sequences with long TR and long TE provide great contrast, while, conversely, sequences with short TR and TE produce images with a greater anatomical fidelity. This dual performance, a notion that had never been expressed as explicitly in imaging, has led to distinguishing between the roles of MRI for detection and tissue characterization (diagnosis and nature). While the choice of an appropriate sequence for characterization has apparently been made immediately with a modulation of T2 weighting, the selection of a detection sequence is less easy. The number of parameters involved (signal-to-noise and contrast-to-noise ratios, spatial resolution, artifacts, imaging time) and the compromise arrangements needed to take them into account explain the lack of consensus as to the optimal sequence for detection. Instead of becoming simpler with time, the issue is increasingly complex, as now fast imaging has been developed in addition to conventional spin echo imaging, and may even supersede it.

The effectiveness of renal transplantation has been considerably improved by the use of cyclosporine as an antirejection agent. However, because of those very same immunosuppressive properties, this substance may lead to several infectious or tumoral complications that raise complex therapeutic problems. This article reports about one case of immunoblastic lymphoma discovered in a patient who received renal transplantation and who had been treated with cyclosporine for two years.

Among all noninvasive techniques, high-resolution ultrasonography used alone has rarely been used for the diagnosis of thrombosis in the calf. Nineteen patients with suspected AVT were examined with ultrasonography and phlebography during 4 months. For each patient, a sonogram and a phlebogram were taken within less than 24 hours and interpreted independently. The sonographic exploration with a high-resolution (5 MHz) transducer covers all deep trunks and muscular veins (soleus or gastrocnemius muscles). The positivity criterion is the persistence of a hypoechogenic endoluminal image under moderate compression. According to the phlebographic data, 65% of the patients present with thrombosis. Ultrasonography has a sensitivity of 95% and a specificity of 99% for the study of the deep trunks. Ultrasonography screens more thromboses than phlebography (23 cases versus 17). On a whole, ultrasonography seems to be more sensitive than phlebography for the diagnosis of recent sural thrombosis.

This article is a review of the current commercial MR contrast media (gadolinium chelates) and of the products that are not yet on the market and are under trial in man (super-magnetic iron oxides, manganese compounds) or only in animals (ferric chelate, liposomes containing gadolinium compounds, gadolinium chelate/human serum albumin compounds, hepatic asialoglycoprotein receptors).

The artificial urinary sphincters are implanted to treat some urinary incontinence. Abdominal plain films allow the checking of the function of the cuff; the diameter of the pressure regulating balloon can be appreciated by ultrasound or plain film. The main complications (bending of the tubules, leak, urethral erosion, rupture of the cuff) and their radiological diagnosis are described.

The low osmolality iodinated contrast agents (ICA), ionic or non ionic are now suggested too replace the usual high osmolality ICA. The main arguments are the better clinical tolerance and a lower renal toxicity. Recent experimental studies have clearly demonstrated that the low osmolality ICA presents a lower renal toxicity. On the rat, we have confirmed that the in vivo renal toxicity of low osmolality ICA, is lower than the high osmolality ICA toxicity. It is clearly demonstrated on man than the enzyme urinary excretion and proteinuria are little or not modified by the low osmolality ICA, but both are increased by high osmolality ICA. These changes are found with a normal glomerular filtration flow. No difference are noted in the creatinine concentration and clearance follow-up. However it is possible that the necessary population of patient to get statistically significative differences between both agents can be superior to the number of patients studied. In clinical practice, we think, that low osmolality ICA must be used for patients presenting one or several risk factors of acute renal failure.

The protal system of 45 normal patients have been retrospectively studied on spin echo MRI sequences (interleaved cuts): multiple artifacts have been evaluated and 24% of them were visualized at the portal system level. Thus, partial volume effect responsible for almost 25% of the artifacts is not always easily seen on a single sequence. Respiratory and aortic artifacts can deteriorate the visualization of the vascular lumen but cannot be confused with a thrombosis. Well-known artifacts, as slice entry phenomenon and even echo rephasing, represent more than 60% of the artifacts: they are readily recognized when they are typical and indicate flowing blood. On the contrary, an other artifact, representing less than 5% of the total and seen at the level of the left portal vein, simulates a thrombus, on T2 weighed images. We conclude that the frequency and polymorphism of the artifacts are limiting factors of MRI value in the diagnosis of portal vein thrombosis.

This observation illustrates the use of CT in the diagnosis of rectosigmoid hemangiomas and the assessment of their extension. The CT appearance of hemangiomas is very specific and therefore allows confirming a diagnosis that is often difficult to make with other radiological techniques and with endoscopy: phleboliths within the thickened rectal wall are a characteristic sign. CT is primarily required when radical surgery is contemplated due to disabling repeated proctorrhagia: it provides a better delineation of trans- and extraparietal hemangioma extension, knowing that adhesion (...).

This observation illustrates how difficult it is to interpret the intravascular signal observed with MRI in cases of portal hypertension. A signal occupying the entire lumen of the portal trunk and branches can be seen, which is constantly observed in the axial as well as coronal planes in the 3 series studied. It is hypointense relative to the liver on T1-weighted images, hyperintense on T2-weighted images: this appearance therefore perfectly mimicks portal thrombosis. Ultrasound combined with pulsed Doppler demonstrates the stagnant blood within the patent portal system. This kind of artifact, which is produced by a very slow flow or even by the standstill of flow, is much more difficult to recognize than the common flow artifacts; the criteria put forward by various authors to distinguish between artifacts and thrombosis are of no avail in this case. Examinations must able to confirm or rule out portal thrombosis in the case of portal hypertension with deceleration of flow. In practice, ultrasound studies, combined with pulsed Doppler in the best cases, is therefore indicated as a first-intension technique.

Fifty four computed (CT) examinations were performed on patients with bladder carcinoma. A pathological assessment was obtained in 24 cases and the accuracy of CT in local staging was 91%. The accuracy of CT in detecting lymph nodes invasion was also 91%. Moreover, CT is helpful in the follow-up of patients under treatment. As it provides a correct pre-therapeutic evaluation in 83% cases, CT appears as an effective examination to perform in the evaluation of bladder carcinoma.

The authors provide a didactic analysis of the errors in perception that can lead to false-negative findings in the detection of advanced rectocolonic cancers with double-contrast enema. They consider 5 categories of images as typical, ie. transverse or horizontal linear opacities, abnormal lumen due to haustral folds on semiaxial views, "pool sign", amputation of the cecum and irregular hypertrophy of the ileocolic valve. These mistakes will become exceptional if the double-contrast images are studied thoroughly using precise rules, and the percentage of false-negative findings in the detection of rectocolonic cancers should thus be reduced to 1%.

The use of the prone position in aortography improves the visualization of the anterior wall of the aorta. This is supported by observation of an obstructed aortobifemoral by-pass and seems interesting in the study of aneurysms. More often, it is useful in case of decreased blood flow or increased local turbulence.

The assessment of the extent of kidney cancers with MRI and CT is compared in 40 patients. The appearance of the tumor with MRI is very variable but always heterogeneous. Specific MRI features (tumoral pseudocapsule) provide a higher overall reliability (OR) than with CT for the detection of expansion beyond the capsule and into the kidney: 80% for 60%. Although the overall reliability of MRI is similar to that of CT (92% for 86%), MRI has proved its superiority for the assessment of the limits of endovenous tumoral expansion because of natural flow/thrombus contrast and of the multiple incidences of exploration. There is no significant difference between MRI (OR = 91%) and CT (OR = 88%) or the detection of lymph node involvement. Invasion of neighboring organs is better assessed with multi-incidence MRI. According to Robson's classification, the OR of MRI (77%) is not significantly higher than that of CT (65%). MRI is still a time-consuming and expensive technique, which should be reserved for cases in which iodine is contraindicated and used as a second-intention technique after CT to confirm the invasion of the capsule if partial nephrectomy is indicated, or the better delineate venous or regional invasion which CT could not assess properly.

Nineteen cases of focal infectious lesions of renal parenchyma studied included 10 cases of acute focal bacterial nephritis (AFBN) and 9 of abscess, cases of pyelonephritis without radiological signs being excluded from this report. Each patient had been investigated by intravenous urography (IVU), ultrasound and CT scan imaging. Comparison of value of the different radiological explorations showed that urographic signs were inconstant and only weakly specific, the most valuable examination being CT scan imaging. The latter images show hypodense zones, clearer with contrast, of a rather triangular form and either single or multiple in AFBN, and mainly nodular images in abscess cases. Ultrasound is of intermediate value, being of high performance in cases of abscess but failing to demonstrate AFBN in about half the cases. However, it should not be totally neglected because of its case of access.

This study was conducted in 10 patients recently treated by peritoneal dialysis, and without a previous history of peritoneal disorders. Its aim was to determine the normal distribution of a two litre liquid effusion in the mesocolic recesses. A detailed description of the anatomy of the supramesocolic peritoneum precedes the study CAT scan results.

When confronted with rectorrhagia in a young patient, combining a straight abdominal examination with a barium enema investigation may reveal the presence of phleboliths, atypical by their large number and central localization, and orientate towards the rare diagnosis of a colorectal hemangioma.

The diagnostic value of lymphography and computed tomography (CT) in the assessment of lymph node invasion by bladder cancers has been compared on the basis of 30 observations. Although computed tomography apparently yields better results (reliability: 93%) than lymphography (reliability: 87%), these findings have no statistical significance. The study of literature shows that the statistical exploitation of the results was seldom carried out. The combination of both exploration techniques seems to improve predictive values, but this improvement was not statistically significant in our study.

This report studies the diagnostic problem raised by benign pedunculated gastric leiomyoma identified by CT scan imaging and associated with hepatic metastases. Evaluation of the angle of attachment to the wall, the conventional feature enabling distinction between malignant and benign submucous tumours is not always a reliable indicator.

Since diagnostic value of double contrast colon imaging is dependent on the colon preparation used, tolerance and efficacy of 4 colon preparations were evaluated by a simple-blind, comparative, randomized study in 185 outpatients. Colon preparation involves variable combinations of 3 means: residue-free diet, laxatives and wash-out enemas. Principal criteria were evaluated under blind conditions by the same investigator during all examinations, with quantitative rating by segment (left, transverse and right colon) of adherence and colon cleanliness, and global assessment of quality of preparation. The 4 groups were comparable: mean age 44.7 years, sex ratio (male/female) 51.3%. Tolerance and compliance were elevated without significant inter-group differences. The colon preparations studied did not allow a homogeneous preparation to be obtained throughout the colon, efficacy in left colon being superior to right colon, whatever the method used. Analysis of cleanliness and adherence by segment failed to show significant differences between procedures, probably related to weak differences in their effectiveness and the strict nature of the study. The use of a global criterion tended to show value of wash-out enemas as a routine procedure, whether in outpatients or in the Radiology department.