Diffusion-weighted magnetic resonance imaging in ileocolonic Crohn's disease: validation of quantitative index of activity.

OBJECTIVES: Magnetic resonance imaging (MRI) allows accurate assessment of Crohn's disease (CD), but requires gadolinium injection. Diffusion-weighted (DW)-MRI yields comparable performances in small bowel CD. We compared the accuracy of DW-MR enterocolonography (MREC) and the magnetic resonance index of activity (MaRIA), and performed an external validation of the Clermont score in assessing inflammation in CD. METHODS: This was an observational prospective study of a single-center cohort. A total of 130 CD patients underwent consecutively MREC with gadolinium injection and DWI sequences between July 2011 and December 2012. RESULTS: Of the 848 evaluated segments (small bowel=352, colon/rectum=496), 175 (20.6%) were active (small bowel=111, colon/rectum=64) defined as MaRIA ≥7. Using a receiver operating characteristic (ROC) curve, we determined an apparent coefficient of diffusion (ADC) threshold of 1.9 × 10(-3) mm(2)/s that yielded a sensitivity and a specificity in discriminating active from nonactive CD of 96.9% and 98.1%, respectively, for the colon/rectum, and 85.9% and 81.6%, respectively, for the ileum. ADC was better correlated to MaRIA ≥7 than related contrast enhancement obtained with injected sequences (P<0.001). The Clermont score (=1.646 × bowel thickness-1.321 × ADC+5.613 × edema+8.306 × ulceration+5.039) was highly correlated with the MaRIA (rho=0.99) in ileal CD but not in colonic CD (rho <0.80). Interobserver agreement was high with regard to ADC measurement (correlation >0.9, P<0.001, and concordance >0.9, P<0001). CONCLUSIONS: DW-MREC is a reliable tool to assess inflammation in colonic (ADC) and ileal (Clermont score) CD and its use in daily practice would avoid gadolinium injection.

Abdominal complications following neutropenia and haematopoietic stem cell transplantation: CT findings.

In haematology units, acute abdominal symptoms are common and often challenging for the clinician in charge. Two haematological conditions that may induce specific diagnoses are of particular concern: neutropenia and haematopoietic stem cell transplantation. Clinical and biological manifestations, including abdominal pain, fever, diarrhoea, hepatic cytolysis, or cholestasis are often non-specific. Computed tomography is often the primary imaging screening technique performed in such patients, as it is widely available, performs well for this indication, and may demonstrate evocative findings. The aim of this review is to provide the spectrum of specific diagnoses encountered and the corresponding key CT features in patients presenting with acute abdominal disorders following neutropenia and/or haematopoietic stem cell transplantation.

Fibrous tumours of the ovary: aetiologies and MRI features.

The ovaries can be affected by a vast variety of tumours, which may be benign or malignant, solid or cystic. Although ultrasonography is often the first examination performed in the evaluation of gynaecological conditions, magnetic resonance imaging is nowadays the most accurate imaging technique in the characterization of ovarian masses. Once the ovarian origin of a pelvic mass has been determined, the detection of any fibrous component within the lesion significantly reduces the spectrum of aetiologies that should be considered. Fibrotic tissue usually displays marked low-signal intensity on T2-weighted sequences at MRI, and enhancement is mostly moderate after intravenous administration of gadolinium chelates. This review aims to provide the main diagnoses to consider at MRI whenever an ovarian tumour, both purely solid or solid and cystic, contains a fibrous component, even if minimally abundant. The corresponding key imaging features are provided.

[Embryology of the heart walls]. / Embryologie des cloisons du cœur.

Although anatomically simple structures, the atrial septum and the ventricular septum have complex embryological origins. Recent findings in molecular biology allowed better comprehension of their formation. As soon as the heart tube is formed, cells migrate from several cardiogenic fields to take part in the septation. Elongation, ballooning, and later inflexion of the heart tube create chamber separating grooves, facing the future septa. The systemic venous tributaries conflate at the venous pole of the heart; it will partially involute while contributing to the atrial septum. The primary atrial septum grows from the atrial roof towards the atrioventricular canal. It fuses there with the atrioventricular cushions, while its upper margin breaks down to form the ostium secundum. Then a deep fold develops from the atrial roof and partly covers the ostium secundum, leaving a flap-like interatrial communication through the oval foramen. It will close at birth. The interventricular septum has three embryological origins. The ventricular septum primum, created during the ballooning process, origins from the primary heart tube. It will form the trabecular septum and the inlet septum. The interventricular ring, surrounding the interventricular foramen, will participate in the inlet septum and also form the atrioventricular conduction axis. The outflow cushions will separate the outflow tract in the aorta and pulmonary artery, and grow to create the outlet septum. After merging with the atrioventricular cushions, they will also be part of the membranous septum.

[CT imaging features of colitis in neutropenic patients]. / Aspects tomodensitométriques des colites chez les patients neutropéniques.

Colitis in neutropenic patients presents with non-specific clinical findings including abdominal pain, fever, diarrhea and abnormal liver function tests. Four diagnoses are relatively more frequent: neutropenic enterocolitis, pseudomembranous colitis, intestinal GVHD and CMV colitis. Knowledge of their respective imaging features combined with epidemiological data frequently leads to the correct diagnosis. The purpose of this paper is to illustrate the imaging features of colitis in neutropenic patients.

Assessment of Maturational Changes in White Matter Anisotropy and Volume in Children: A DTI Study.

BACKGROUND AND PURPOSE: Anisotropy is a good indicator of white matter fascicle macrostructure and organization but the interpretation of its changes with age remains difficult. The increase of WM fascicle fractional anisotropy with time and its relationship with WM fascicle volume have never been examined during childhood. We studied the maturation of associative WM fascicles during childhood using MR imaging-based DTI. We explored whether the fractional anisotropy increase of the main WM fascicles persists beyond the period of brain growth and is related to WM fascicle volume increase. MATERIALS AND METHODS: In a series of 25 healthy children, the fractional anisotropy and volume of 15 associative WM fascicles were calculated. Several regression linear mixed models were used to study maturation parameters (fractional anisotropy, volume, and total telencephalon volume) considered as dependent variables, while age and sex were independent variables (the variable identifying the different WM fascicles was considered as a repeated measure). RESULTS: In children older than 8 years of age, WM fascicle fractional anisotropy increased with age (P value = .045) but not its volume (P value = .7) or the telencephalon volume (P value = .16). The time course of WM fascicle fractional anisotropy and volume suggested that each WM fascicle might follow a specific pattern of maturation. CONCLUSIONS: The fractional anisotropy increase of several WM fascicles after 8 years of age may not result from an increase in WM fascicle volume. It might be the consequence of other developmental processes such as myelination.

[Fibrolamellar hepatocellular carcinoma in a patient with chronic viral B hepatitis]. / Carcinome hépatocellulaire fibrolamellaire chez un patient suivi pour hépatite chronique virale B.

In most cases, fibrolamellar hepatocellular carcinoma has specific and distinctive histopathological features that distinguish it from hepatocellular carcinoma. Magnetic resonance imaging can provide characteristic features to obtain a diagnosis of this entity. We report a case of fibrolamellar hepatocellular carcinoma with a radiological-pathological correlation in a 37 year-old man with chronic viral hepatitis B without cirrhosis who underwent right hepatectomy.

Existence of a rotational axial component in the human humeral medullary canal.

To explain surgical findings, we studied the anatomy of the human humeral medullary canal on a series of 28 bones in 16 patients and 9 dried bones. A methodology is described to find angle of medullary canal on CT scans regarding to an epicondylar reference axis. We found a constant tri-dimensional spiral shape of the medullary canal in the distal part of the bone. The relations between this first description and the literature are discussed.

[Endovascular treatment of SVC syndrome from neoplastic origin: a review of 34 cases]. / Traitement endovasculaire du syndrome cave supérieur d'origine néoplasique: à propos de 34 patients.

PURPOSE: To report our experience with the treatment of 34 patients with SVC syndrome from neoplastic origin using the Wallstent. MATERIALS AND METHODS: Thirty-four patients were treated between January 2000 and February 2007: 21 males and 13 females, aged 44-81 years, with non-small-cell lung carcinoma in 27 cases (79%), small-cell lung carcinoma in 5 cases (15%) and metastatic breast adenocarcinoma to the mediastinum in 2 cases (6%). All patients were treated using the stainless steel self-expanding Wallstent. A dual brachial-femoral access was used in all cases. RESULTS: Stent placement was possible in all cases. Per procedure acute respiratory distress occurred in 2 cases: 1 case of acute pulmonary edema and 1 case of tamponade. Symptoms resolved within 24 hours. Twenty-six patients died from disease progression, 8 during the first month, and 16 within 32-545 days post-procedure (mean: 213.4 days). Five patients with recurrent SVC syndrome underwent repeat treatment (restenosis in 3 cases, fracture in 1 case, thrombosis in 1 case), for primary and secondary patency rates of 81% and 100%. CONCLUSION: Palliative stent treatment of neoplastic SVC syndrome is reliable, safe and provides long-standing improvement in quality of life.

Centropontine myelinolysis after correction of hyponatremia: role of associated hypokalemia.

BACKGROUND: Patients with severe hyponatremia have a high risk for centropontine myelinolysis (CPM) during treatment, but the incidence rate and risk factors have not been well-assessed. METHODS: This study was conducted in a medical intensive care unit (ICU) of a university teaching hospital. All patients with a serum sodium concentration < 120 mmol/l and a serum osmolality level < 250 mosmol/kg upon ICU admission were enrolled in this prospective study and were included if they underwent a baseline brain computerized tomography scan (CT scan) and a follow-up brain magnetic resonance imaging 1 month after admission. The diagnosis of CPM was based on cerebral magnetic resonance imaging findings, i.e. T1-weighted images with T2-weighted images showing hyperintense signal in the corresponding areas which were not apparent on the initial cerebral CT scan. RESULTS. Of the 22 patients included, 12 were considered as having acute hyponatremia and 8 were chronic alcoholics. In 12 patients, the increase in serum sodium level was < 12 mmol/I in any 24-hour period. CPM was diagnosed in 7/22 patients (31.8%) and was asymptomatic in 4 of them. CPM was present in 4 patients with acute hyponatremia and in 4 chronic alcoholics. It was associated with a lower baseline potassium level (p = 0.05) and NaCl administration during the first 24 hours (p = 0.005). However, non-acute hyponatremia, chronic alcoholism and rapid correction of serum sodium did not appear as risk factors. CONCLUSION: The incidence rate of CPM following severe hyponatremia is high and can develop even when there is a slow correction of serum sodium level. Hypokalemia is a predisposing factor.

[Impact of computed tomography on patient's care in nontraumatic acute abdomen: 90 patients]. / Contribution du scanner à la prise en charge des tableaux abdominaux aigus non traumatiques: étude de 90 patients.

OBJECTIVES: To determine the contribution of computerized tomography (CT) to the management of nontraumatic acute abdomen, to evaluate interobserver agreement and the contribution of CT to cost control, to look for the predictive factors of CT. PATIENTS: and method. Ninety prospectively included patients, admitted for nontraumatic acute abdomen and examined by a surgeon, received CT examination. Diagnosis and treatment 1) envisioned before and 2) defined after CT, and 3) finally retained were compared, and the interobserver agreement was calculated after the second reading. The predictive value of the clinical and biological criteria as well as the radiological criteria characterizing these patients was sought. RESULTS: CT was contributive in 68.9% of cases, with a reliable diagnosis and treatment strategy, defined after CT examination, for 92.2% and 90%, respectively. Interobserver agreement was 93.3%. CT contributed to reducing costs in 15.5% of patients, for an additional cost estimated at 104-139 euros. The positive predictive factors of the CT contribution were age over 70 years, localized symptoms, fever, and high CRP. CONCLUSION: In agreement with the literature, in our study CT appears to be a choice examination to guide patient care in nontraumatic acute abdomen.

[Type III endoleaks at follow-up of covered descending thoracic aortic stent-grafts: report of 3 patients]. / Endofuites de type III au cours du suivi d'endoprothèses couvertes aortiques thoraciques descendantes: 3 patients.

PURPOSE: To describe the imaging work-up and management of type III endoleaks detected after covered stent-graft treatment of descending thoracic aortic aneurysms. PATIENTS AND METHODS: Retrospective study of circumstances surrounding the diagnosis, management and outcome type III endoleaks occuring in 3 of 18 patients following covered stent-graft treatment of descending thoracic aortic aneurysms between April 1998 and July 2005. The endoleaks were detected at a mean follow-up of 22 months (19-24 months) after stent-graft placement. RESULTS: The type III endoleaks were detected on scheduled follow-up CT examinations in asymptomatic patients. Endovascular management was proposed at a mean interval time of 4.4 months (1 week - 11 months) after diagnosis of the endoleak, and was successful in all 3 cases. One patient died 1 month after endovascular repeai of the leak, 1 patient required surgical management at 14 months for new recurrence, and 1 patient had a favorable outcome at 2 months. CONCLUSION: Follow-up of patients after covered stent-graft treatment of descending thoracic aortic aneurysms is required. Prompt endovascular repair of delayed complications may be possible, but surgical management may become necessary.

[Transverse reductional anomaly and atypical fibrodysplasia ossificans progressiva: A case diagnosed late]. / Anomalie réductionnelle transverse et fibrodysplasie ossifiante progressive atypique, à propos d'un cas de diagnostic tardif.

Fibrodysplasia ossificans progressiva (FOP) is a rare disease characterized by the association of congenital bone abnormalities and extraskeletal ossification flare-ups occurring in muscles and fasciae. Early diagnosis is important to prevent ossification flare-ups, but some atypical presentations can lead to errors in diagnosis and therefore delay. Here, we report on a case of an atypical presentation of FOP in a girl, in whom prominent transverse reductional abnormalities delayed diagnosis. The patient developed extraskeletal ossifications and progressive fibrosis that led to motor restrictions. Since early diagnosis is important, we discuss the clinical presentations of FOP and the differential diagnoses.

[Long-term MRI follow-up of aortic dissection in 56 patients: therapeutic impact]. / Surveillance par IRM des dissections aortiques: impact thérapeutique à propos du suivi de 56 patients.

PURPOSE: To retrospectively assess the value of MRI in long-term follow-up of aortic dissection (AD) and its impact on therapy. MATERIALS AND METHODS: Comparison of clinical progression and analysis of 215 MRI examinations performed on 56 patients in our center from 1991 to 2002. RESULTS: Twenty-six patients (46%) had AD complications: 14 (54%) were asymptomatic and eight (31%) had subsequent surgical repair (native aorta upstream prosthesis disease in three patients and aneurismal dilatation of false lumen in five cases). Of the eight patients with secondary surgery, five (63%) were clinically asymptomatic. The delay between initial dissection and secondary surgery was less than 5 years in five patients and exceeded 10 years in three cases. The remaining 30 patients (54%) had unmodified radiological findings after a mean follow-up of 3.5 years (6 months to 9 years). CONCLUSION: MRI depicted AD complications in long-term follow-up of sometimes asymptomatic patients, allowing for adaptation of surgical treatment in 26 cases (46%).

[Femoral superficial artery angioplasty: long term results, initial predictive factors. 101 patients]. / Angioplastie fémorale superficielle: résultats à long terme, facteurs initiaux de bon pronostic. A propos de 101 patients.

OBJECTIVE: To evaluate immediate results, clinical improvement, long-term patency and predictive factors of long-term outcome after superficial femoral artery percutaneous angioplasty. PATIENTS AND METHODS: Restrospective monocentric study of 101 patients (142 lesions: 105 stenoses and 37 occlusions) technical results, long-term patency (19 months), and clinical improvement (27,5 months) were analyzed. A multifactorial analysis was performed. RESULTS: Technical success was obtained in 99%, complications and mortality rates were respectively 3% and 2%. At the end of follow-up, 55 patients were clinically improved (20 lost to follow-up), and femoral artery remained patent in 62 patients (10 to follow-up). Statistical analyses revealed 8 significant predictive factors of a good outcome (P<0.05): female gender, non-diabetic, at least one patent artery below the knee, AHA classification <2, no stent, treatment of an occlusion, number of dilatations<3, treatment by statins for hypercholesterolemia. CONCLUSION: Femoral superficial artery angioplasty is usually achieved with low complication rate. We found eight factors predictive of long-term outcome, to keep in mind when indications are discussed.

[Helical CT of abdominal aorta]. / Angioscanner hélicoïdal de l'aorte abdominale.

The purpose was to illustrate that single or multirow spiral CT angiography has become the main modality for the examination of the abdominal aorta. Our multidisciplinary group investigates weekly 15 abdominal aortas, with a single slice spiral CT since 1995, and a 4 row detector spiral CT since 1999. CT scans protocols and parameters optimization for the 2 CT systems are described. Indications and results of CT to investigate the various abdominal aortic diseases are illustrated and discussed: aneurisms (pretherapeutic staging, selection of indications of endovascular stent-grafting); obstructive aorto-arteriopathies (pretherapeutic staging, follow up after endovascular revascularization); dissection (diagnosis, pretherapeutic staging, follow up); inflammatory diseases; normal patterns and principal complications after surgery. Situations where multislice CT is superior to single slice CT and compared advantages of MRI are discussed. CT is at the present time the main technique to image abdominal aorta. Multislice CT is especially interesting to explore the whole aorta, poly traumatisms, and to plan and follow up endovascular treatments.

Fat-containing lesions of the liver: a pictorial essay.

The presence of fat within a hepatic lesion is unusual and can help to direct the radiologist's diagnosis. The aim of this iconographic review is to specify the various hepatic lesions that may contain fat and their appearance particularly on MRI. A histological correlation is also suggested for the most commonly found tumors. The identification of fat within a hepatic tumor, along with other radiological signs and reflection on the clinical and epidemiological context, can lead to a diagnosis being reached or suggested, with confirmation if necessary, by a pathological examination.

Leg cycling tracking by dynamic vision.

This study describes a method of tracking of human body limbs from a monocular sequence of perspective images. These objects and the associated articulations must be modelled. The principle of the method is based on the interpretation of image features as the three-dimensional perspective projections points of the object model and an iterative process method to compute the model position in accordance with the analysed image. This attitude is filtered (Kalman filter) to predict the model position relative to the next image of the sequence. The image features are extracted locally according to the computed prediction. Tracking experiments, illustrated in this study by a leg cycling sequence, have been conducted to demonstrate the viability of the approach.