C. Hoeffel

Diffusion-weighted magnetic resonance imaging for the assessment of fibrosis in chronic hepatitis C†

Liver biopsy is the gold standard for assessing fibrosis but has several limitations. We evaluated a noninvasive method, so‐called diffusion‐weighted magnetic resonance imaging (DWMRI), which measures the apparent diffusion coefficient (ADC) of water, for the diagnosis of liver fibrosis in patients with chronic hepatitis C virus (HCV). We analyzed 20 healthy volunteers and 54 patients with chronic HCV (METAVIR: F0, n = 1; F1, n = 30; F2, n = 8; F3, n = 5; and F4, n = 10) prospectively included. Patients with moderate‐to‐severe fibrosis (F2‐F3‐F4) had hepatic ADC values lower than those without or with mild fibrosis (F0‐F1; mean: 1.10 ± 0.11 versus 1.30 ± 0.12 × 10−3 mm2/s) and healthy volunteers (mean: 1.44 ± 0.02 × 10−3 mm2/s). In discriminating patients staged F3‐F4, the areas under the receiving operating characteristic curves (AUCs) were 0.92 (±0.04) for magnetic resonance imaging (MRI), 0.92 (±0.05) for elastography, 0.79 (±0.08) for FibroTest, 0.87 (±0.06) for the aspartate aminotransferase to platelets ratio index (APRI), 0.86 (±0.06) for the Forns index, and 0.87 (±0.06) for hyaluronate. In these patients, the sensitivity, specificity, positive predictive value, and negative predictive value were 87%, 87%, 72%, and 94%, respectively, with an ADC cutoff level of 1.21 × 10−3 mm2/s. In discriminating patients staged F2‐F3‐F4, the AUC values were 0.79 (±0.07) for MRI, 0.87 (±0.05) for elastography, 0.68 (±0.09) for FibroTest, 0.81 (±0.06) for APRI, 0.72 (±0.08) for the Forns index, and 0.77 (±0.06) for hyaluronate. Conclusion: This preliminary study suggests that DWMRI compares favorably with other noninvasive tests for the presence of significant liver fibrosis. (HEPATOLOGY 2007.)

Effectiveness of MR enterography for the assessment of small-bowel diseases beyond Crohn disease.

The use of cross-sectional imaging techniques for the noninvasive evaluation of small-bowel disorders is increasing. The effectiveness of magnetic resonance (MR) enterography for the evaluation of Crohn disease, in particular, is well described in the literature. In addition, MR enterography has an evolving though less well documented role to play in the evaluation of other small-bowel diseases, including various benign and malignant neoplasms arising in isolation or in polyposis syndromes such as Peutz-Jeghers, inflammatory conditions such as vasculitis and treatment-induced enteritis, infectious processes, celiac disease, diverticular disease, systemic sclerosis, and bowel duplication. MR enterography may be useful also for the evaluation of intermittent and low-grade small-bowel obstructions. Advantages of MR imaging over computed tomography (CT) for enterographic evaluations include superb contrast resolution, lack of associated exposure to ionizing radiation, ability to acquire multiplanar primary image datasets, ability to acquire sequential image series over a long acquisition time, multiphasic imaging capability, and use of intravenous contrast media with better safety profiles. MR enterography also allows dynamic evaluations of small-bowel peristalsis and distensibility of areas of luminal narrowing and intraluminal masses by repeating sequences at different intervals after administering an additional amount of the oral contrast medium. Limitations of MR enterography in comparison with CT include higher cost, less availability, more variable image quality, and lower spatial resolution. The advantages and disadvantages of MR enterography performed with ingestion of the oral contrast medium relative to MR enteroclysis performed with infusion of the oral contrast medium through a nasoenteric tube are less certain.

MR Lymphography of Abdominal and Retroperitoneal Lymphatic Vessels

OBJECTIVE The abdominal and retroperitoneal lymphatic system is characterized by numerous anatomic variations. Our objective is to review MR lymphographic features of normal anatomy and abnormal conditions. CONCLUSION MR lymphography is a noninvasive technique that is well suited for the examination of abdominal and retroperitoneal lymphatic vessels.

Pouchography, CT, and MRI Features of Ileal J Pouch-Anal Anastomosis

OBJECTIVE Our objective is to describe pouchography, CT, and MRI features of the J-shaped pouch, both normal and with pouch-related complications. CONCLUSION Pouchography is performed before closure of the loop ileostomy to assess the integrity of the ileal pouch and anastomosis. CT and MRI can be performed when postoperative complications, such as small-bowel obstruction, pouchitis, leakage, abscess, intramural hematoma, desmoid tumor, or recurrent Crohns disease, are suspected.

Utilisation du jus d’ananas en tant qu’agent de contraste négatif en cholangiopancréatographie par résonance magnétique

Resume Objectifs La qualite des examens de cholangiopancreatographie par resonance magnetique (CPRM) est frequemment degradee par le signal eleve du contenu digestif sur les sequences fortement ponderees en T2. L’objectif de cette etude est d’evaluer les resultats obtenus par l’ingestion de jus d’ananas en tant qu’agent de contraste negatif en CPRM. Materiels et methodes Nous avons compare les resultats de la CPRM de 50 patients ayant ingere du jus d’ananas et de 50 patients ayant ingere un produit de contraste paramagnetique (ferumoxsil-Lumirem ® ). Les observateurs ne connaissaient pas la nature du produit de contraste ingere. La qualite des examens a ete analysee en terme de suppression du signal au sein de l’estomac, du cadre duodenal et du grele proximal et en terme de visualisation du canal pancreatique, des voies biliaires intrahepatiques et de la voie biliaire principale. In vitro, nous avons analyse l’intensite du signal de differents jus d’ananas disponibles sur le marche, en se servant de sequences ponderees en T1, de sequences ponderees en T2 et de sequences de CPRM. L’intensite du signal a ete correlee avec la concentration de manganese mesuree par spectrometrie d’emission atomique. Finalement, les observateurs ont compare les gouts respectifs du jus d’ananas et du ferumoxsil. Resultats Sur les sequences de CPRM, les resultats etaient equivalents en terme de suppression de signal de l’estomac, du cadre duodenal et du grele proximal apres ingestion de jus d’ananas ou de ferumoxsil. La visualisation du canal de Wirsung, des voies biliaires intrahepatiques et de la voie biliaire principale etait equivalente apres ingestion d’ananas ou de ferumoxsil. L’intensite du signal des differents jus d’ananas sur les sequences ponderees en T2 et sur les sequences de CPRM etait bien correlee avec la concentration de manganese mesuree pour chacun des jus par spectrometrie. D’importantes variations de la concentration de manganese ont ete observees entre les differents jus d’ananas testes. La concentration de manganese variait entre 3,65 et 27,24 mg/L. Les observateurs ont considere que le jus d’ananas avait un « bon » ou un « tres bon » gout alors que le ferumoxsil avait un « mauvais » ou « tres mauvais » gout. Conclusion L’ingestion de jus d’ananas permet d’obtenir une diminution efficace du signal du tractus digestif en CPRM d’une facon comparable a celle qui est obtenue avec les produits de contraste paramagnetiques. Comme la concentration de manganese est largement variable dans les differents jus d’ananas disponibles dans le commerce, un jus d’ananas a haute concentration de manganese doit etre selectionne.

MRI of Rectal Disorders

OBJECTIVE The objective of this pictorial essay is to provide a review of the diseases involving the rectal wall with an emphasis on the key clinical and radiologic differentiating features. CONCLUSION A wide spectrum of disease processes can involve the rectum in adults. MRI is the technique of choice in the definitive diagnosis of these disease conditions, mainly because of its superior tissue contrast differentiation.

Local colorectal cancer recurrence: pelvic MRI evaluation

Surveillance of colorectal cancer is currently based on dosage of tumoral markers, colonoscopy and multidetector row computed tomography. However, pelvic magnetic resonance imaging (MRI) and PET–CT are two second-line useful imaging modalities to assess colorectal cancer local recurrence (LR). The anatomical information derived from MRI combined to the functional information provided by diffusion-weighted imaging currently remain of value. Pelvic MRI is accurate not only for detection of pelvic colorectal recurrence but also for the prediction of absence of tumoral invasion in pelvic structures, and it may thus provide a preoperative road map of the recurrence to allow for appropriate surgical planning. As always, correlation of imaging and clinical findings in the multidisciplinary forum is paramount. MRI can also be used to follow-up LR treated with radiofrequency ablation. The aim of this review is to discuss clinical practice and application of MRI in the assessment or pelvic recurrence from colorectal cancer.

Redundant Publication in the Journal Radiology

PURPOSE To retrospectively quantify the incidence of redundant publication in the journal Radiology and to compare the present study findings with those published for other journals and medical specialties. MATERIALS AND METHODS Two readers estimated the incidence of the redundant publication of original articles in Radiology in the year 2001. Original research articles published in 2001 were analyzed by searching MEDLINE on the PubMed server to identify articles that may have represented a duplication of the original Radiology article. MEDLINE was searched between January 1999 and December 2003 by using the surname and initial(s) of the first author. Potentially redundant articles were identified after similarities in titles and abstracts were analyzed. The full versions of all potentially redundant articles and of the corresponding index articles were then retrieved from the library. The potentially redundant article was then compared with the index article. Criteria for redundant publication were as follows: Compared with the index article, the potentially duplicate article had (a) a similar hypothesis, (b) a similar number of subjects, (c) similar results, (d) at least one author in common, and (e) no or little new information. RESULTS In 2001, 362 original research articles were published in Radiology. Two instances of redundant publication were found among these articles, and both were considered to be partially redundant publications due to series expansions (ie, increased numbers of study subjects) of 50% and 52%. CONCLUSION Redundant publication appears to be less frequent in Radiology than in the other journals and specialties for which redundant publication information has been reported.

Magnetic resonance imaging of the ischiorectal fossa : Spectrum of disease

Objective: Pelvic magnetic resonance imaging (MRI) studies are widely used to assess the rectum, anal canal, and their environment. The purpose of this article is to review the current role of MRI in the evaluation of diseases involving the ischiorectal fossa and their imaging features. Conclusions: The radiologist plays an essential role in the evaluation of some conditions typically located in this space and of other conditions that occasionally involve this area or invade the ischioanal space. The accurate assessment of these diseases that MRI provides further cements its role as the primary technique for the evaluation of pelvic pathology.

Performance de l'échographie de contraste en pathologie hépatique: synthèse de la littérature.

The advent of second-generation microbubble ultrasound contrast agents and the development of contrast specific ultrasound techniques improved the ability of contrast enhanced ultrasound (CEUS) in detecting and characterizing focal liver lesions, opening new prospects in liver imaging. A Medline search in June 2008 identified 72 published studies that used CEUS in focal liver lesion detection, characterization, and follow-up to monitor tumor ablation procedures and antiangiogenic treatment. The purpose of this paper, based on literature review, is to describe the technical recommendations when using CEUS for liver imaging and to define the different vascular patterns of the most relevant benign and malignant lesions. Diagnostic performance of CEUS and the important clinical indications are also presented and discussed. CEUS is increasingly accepted in clinical use for diagnostic imaging and post-interventional workup liver imaging. It may replace many computed tomography and magnetic resonance imaging examinations in the near future, according to the European Federation of Societies for Ultrasound in Medicine and Biology guidelines.