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.

[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.

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.

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.

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.

Hepatic haemangioma: common and uncommon imaging features.

The haemangioma, the most common non-cystic hepatic lesion, most often discovered by chance, may in certain situations raise diagnostic problems in imaging. In this article, the authors first demonstrate that the radiological appearance of the hepatic haemangioma, in its typical form, is closely related to three known histological sub-types. They then show that certain atypical features should be known in order to establish a diagnosis. They also observe the potential interactions between the haemangioma, an active vascular lesion, and the adjacent hepatic parenchyma. Finally, they discuss the specific paediatric features of hepatic haemangiomas and illustrate the case of a hepatic angiosarcoma.

[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.

Diffusion-weighted magnetic resonance imaging for detecting and assessing ileal inflammation in Crohn's disease.

BACKGROUND: Whether diffusion-weighted imaging (DWI)-MRI is of value in detecting and assessing inflammation of ileal Crohn's disease (CD) remains poorly investigated. AIM: To compare DWI-MR enterography (MRE) with conventional MRE in estimating inflammation in small bowel CD, to determine an apparent diffusion coefficient (ADC) threshold to differentiate active from non-active lesions and to assess inter-observer agreement. METHODS: Thirty-one CD patients from the Clermont-Ferrand IBD unit with ileal involvement were consecutively and prospectively included between April and June 2011. All patients underwent DWI-MRI to detect the digestive segment with the most severe lesions, which was then used to calculate the ADC. Qualitative and quantitative results were compared with conventional MRE including MaRIA (Magnetic Resonance Index of Activity) score calculation and independent activity predictors (wall thickening, oedema, ulcers). Each examination was interpreted independently by two radiologists blinded for clinical assessment. RESULTS: Seventeen patients (54.8%) had active CD as defined by the MaRIA score ≥7. DWI hyperintensity was highly correlated with disease activity evaluated using conventional MRE (P = 0.001). Qualitative analysis of DW sequences determined sensitivity, specificity, positive predictive value and negative predictive value as 100%, 92.9%, 94.4% and 100% respectively. Quantitative analysis using a cut-off of 1.6 × 10(-3) mm(2)/s for ADC yielded sensitivity and specificity values of, respectively, 82.4% and 100%. Inter-observer agreement was high with regard to DWI hyperintensity (κ = 0.69, accuracy rate = 85.7%) and ADC (correlation = 0.74, P < 0.001, and concordance = 0.71, P < 0.001). CONCLUSION: DWI-MR enterography is a well-tolerated, non-time-consuming and accurate tool for detecting and assessing inflammation in small bowel Crohn's disease.

Posterior reversible encephalopathy syndrome (PRES): features on CT and MR imaging.

Posterior reversible encephalopathy syndrome (PRES) is a rare but severe condition of the central nervous system. It develops in a variety of clinical settings and it has diverse patterns of expression, which can sometimes make diagnosis difficult. Characteristic features are often demonstrated on computed tomography imaging and/or magnetic resonance imaging, meaning that when there is a suspicious clinical picture, this diagnosis should suggest itself. However, clinicians should be aware of some of the less typical features in order to more fully understand this condition, in which early treatment is key to good clinical progress.

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.

Internal hernia of the broad ligament: CT diagnosis for laparoscopic management.

One per cent of cases of mechanical occlusion of the small intestine are caused by internal hernias, the rarest type being an internal hernia through the broad ligament of the uterus, and representing approximately 5% of cases. While "conventional" treatment of mechanical occlusions of the small intestine is based on laparotomy, a laparoscopic approach is feasible in nearly half of cases, with an acceptable rate of morbidity. Preoperative diagnosis has for a long time been difficult but the usefulness has recently been emphasized of computed tomography. We report the cases of two patients who presented an internal hernia of the right broad ligament diagnosed with CT who afterwards underwent laparoscopic surgery.

[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.

[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.