M. Louis

Adhesive Capsulitis of the Shoulder: Value of Inferior Glenohumeral Ligament Signal Changes on T2-Weighted Fat-Saturated Images

OBJECTIVE The objective of our study was to evaluate the performance of MRI for the diagnosis of adhesive capsulitis using signal intensity changes of the inferior glenohumeral ligament on T2-weighted fat-saturated sequences. MATERIALS AND METHODS MR images of 34 shoulders with a final clinical diagnosis of adhesive capsulitis were compared with those of an age-matched control group (34 shoulders) with no clinical signs of adhesive capsulitis. MR images were acquired before and after IV injection of gadolinium and were evaluated by two readers. The T2 signal intensity at the inferior glenohumeral ligament, the thickness of the coracohumeral ligament, and whether there was obliteration of subcoracoid fat were evaluated on unenhanced images. Enhancement at the inferior glenohumeral ligament and enhancement at the rotator interval were evaluated on contrast-enhanced images. The sensitivity, specificity, and interobserver variability of these signs were calculated. RESULTS T2 hyperintensity of the inferior glenohumeral ligament showed a high sensitivity (85.3-88.2%) and high specificity (88.2%) for the diagnosis of adhesive capsulitis with excellent interobserver variability (κ = 0.85). Signal analysis at the inferior glenohumeral ligament presented a higher sensitivity and a better interobserver agreement than the other signs of adhesive capsulitis evaluated. Gadolinium injection did not increase the performance of the inferior glenohumeral ligament signal analysis. An extracapsular hyperintense layer on T2-weighted images was identified as a new sign of adhesive capsulitis. CONCLUSION T2 capsular signal intensity change offers a high performance for the diagnosis of adhesive capsulitis without the need for IV or intraarticular contrast injection.

Evaluation of the Diagnostic Performance of Tomosynthesis in Fractures of the Wrist

OBJECTIVE The purpose of our study was to define the diagnostic value of tomosynthesis compared with standard radiography and CT in wrist injuries. MATERIALS AND METHODS One hundred consecutive patients with acute wrist trauma were investigated with standard radiography, tomosynthesis, and CT. Reference results were those obtained with CT; follow-up monitoring of the patients; and, in some cases, MRI (n=13). Three readers interpreted the findings independently, each using a PACS workstation, and categorized the cases into four groups: fracture of the radius, fracture of the scaphoid, fracture of another bone, and absence of fracture. RESULTS Fifty-seven percent of the patients had a fracture. The interobserver kappa value varied between 0.54 and 0.59 for standard radiography, between 0.66 and 0.69 for tomosynthesis, and between 0.84 and 0.89 for CT. The sensitivity of standard radiography varied between 61% and 80% and specificity between 65% and 83%. The sensitivity of tomosynthesis ranged between 77% and 87%, and specificity between 76% and 82%. Ranges of sensitivity and specificity for CT were 93-95%, and 86-95%, respectively. CONCLUSION The diagnostic value of tomosynthesis is superior to that of standard radiography but inferior to that of CT.

The nerves around the shoulder.

Neuropathies of the shoulder are considered to be entrapment syndromes. They are relatively common, accounting for about 2% of cases of sport-related shoulder pain. Many instances involve suprascapular neuropathy, but the clinical diagnosis is often delayed because of nonspecific symptoms. Classically, EMG is the gold standard investigation but MRI currently reveals muscular abnormality in 50% of cases. Muscle edema, the most characteristic symptom, is nonspecific. In general, the topography of edema, the presence of a lesion compressing the nerve and clinical history contribute to the diagnosis. Although atrophy and fatty degeneration may persist after the disappearance of edema, they are rarely symptomatic. The main differential diagnosis is Parsonage-Turner syndrome. Evidence of a cyst pressing on a nerve may prompt puncture-infiltration guided by ultrasonography or CT-scan.

L’œdème médullaire : définition, valeur diagnostique et pronostique

Bone marrow edema: definition, diagnostic value and prognostic value Bone marrow edema is easily identified on MRI. The terminology suggests that the water content of bone marrow is increased when it is T1W hypointense and T2W hyperintense. It is a misnomer since, histologically, the abnormality does not correspond to marrow edema. The histological findings vary based on the underlying etiology and the presence of fibrosis or inflammatory infiltrate is frequent and often predominant. In France, this terminology is used routinely to describe such lesions. The term osteitis is preferred to describe these marrow signal changes in the setting of rheumatic joint diseases. The detection of bone marrow edema is important because of its diagnostic and prognostic value. It occurs in isolation and is reversible in patients with bone contusion and complex regional pain syndrome. It indicates underlying structural damage and may modify management in patients with rheumatoid arthritis or spondylarthropathies. MR scores for disease activity rely mainly on the presence of marrow edema. Finally, diffusion weighted MR allows quantification of marrow edema and could be more sensitive than conventional MRI to detect inflammation. The purpose of this article is to review the imaging features of marrow edema, review the underlying etiologies and its diagnostic and prognostic value.

Musculoskeletal wide detector CT: Principles, techniques and applications in clinical practice and research

A progressive increase in the detector width in CT scanners has meant that advanced techniques such as dynamic, perfusion and dual-energy CT are now at the radiologists disposal. Although these techniques may be important for the diagnosis of various musculoskeletal diseases, data acquisition and interpretation can be challenging. This article offers a practical guide for the use of these tools including acquisition protocol, post-processing options and data interpretation based on 7 years of clinical experience in a tertiary university hospital.

Wide area detector CT perfusion: Can it differentiate osteoid osteomas from other lytic bone lesions?

PURPOSE To compare the enhancement dynamics of osteoid osteomas with other benign and malignant lytic bone lesions using CT perfusion. PATIENTS AND METHODS CT perfusion parameters of 15 patients with a final diagnosis of osteoid osteoma, 15 patients with lesions that mimic osteoid osteomas and 26 patients with other bone lytic lesions were compared. RESULTS Enhancement curve morphology of the osteoid osteomas was significantly different from its mimickers. All osteoid osteomas had an early enhancement with a delay between nidus and arterial peak below 30 seconds. Eighty percent of the mimickers demonstrated a slow and progressive enhancement. The perfusion parameters of the other lytic bone lesions were similar to those of the osteoid osteomas in 46.1% of the patients. CONCLUSION Early enhancement is suggestive but not pathognomonic of osteoid osteomas. Absent or delayed enhancement in similar lesions should evoke an alternative diagnosis. The same contrast enhancement dynamics of osteoid osteomas can be seen in other bone lesions, both malignant and benign.

Musculoskeletal Wide-Detector CT Kinematic Evaluation: From Motion to Image.

Kinematic computed tomography (CT) allows identification of fine positional anomalies of bones during motion and under stress and has a potential role in the evaluation of dynamic joint diseases. The increasing width of CT detector systems has made kinematic CT clinically available. Information on acquisition protocol, patient preparation, and the influence of motion on image quality is scarce in the literature despite the obvious importance for the clinical application of this technique. In this article we review the current knowledge on the relation between motion and artifacts, recommendations for the acquisition protocol, as well as current indications for kinematic CT.

MRI appearance of the distal insertion of the anterior cruciate ligament of the knee: an additional criterion for ligament ruptures

ObjectiveAnterior cruciate ligament tears are frequent and if not diagnosed may lead to relevant patient disability. Magnetic resonance imaging is the method of choice for the non-invasive diagnosis of these tears. Despite the high performance of this method some cases are challenging and the criteria described in the literature are not sufficient to reach a diagnosis. We propose a systematic method for the evaluation of anterior cruciate ligament tears based on the aspect of its distal portion.Materials and methodsMagnetic resonance studies of 132 knees were evaluated in correlation with arthroscopy. The performance of the proposed method was compared with that of classic imaging signs of anterior cruciate ligament tear. The impact of image quality and reader expertise on the proposed method and the classic signs of tear were taken into account.ResultsThis method had a sensitivity and specificity of 91.1% and 82.9% for the detection of abnormal ACLs. The interobserver agreement (kappa) of the proposed method was significantly higher than that of the classic signs at all levels of expertise (0.89 vs 0.76). This method was not influenced by image quality. Distal ACL analysis identified more partial tears and synovialization (granulation scar tissue) than the conventional method (71% vs 58.5% for partial tears and 83.5% vs 58.5% for synovialization).ConclusionThe proposed classification has a high performance and reproducibility for the identification of abnormal anterior cruciate ligament. The results were influenced neither by the level of expertise of the readers nor by the image quality.

OA-WS-48 Courbes de rehaussement des tumeurs osseuses et des parties molles : comparaison entre scanner et IRM

Objectifs L’arrivee de la nouvelle generation de scanners a large detecteur permet d’etudier la perfusion tumorale de maniere plus simple. Nous nous sommes interesses aux courbes de rehaussement : existe-t-il des differences entre les courbes obtenues en scanner et en IRM? Materiels et methodes Etude retrospective de 21 lesions tumorales osseuses ou des parties molles ayant un diagnostic anatomopatholo-gique. Les patients ont beneficie d’une etude de la perfusion tumorale en IRM et en scanner 320 canaux (Aquilion One). L’etude porte sur le type de courbe selon Van Rijswijk et le delai du pic tumoral. Resultats Le type de courbe est identique entre les deux techniques d’imagerie dans 90% des lesions. Le delai du pic tumoral est par contre significativement different : il est atteint plus rapidement sur l’acquisition scanographique avec un ecart moyen de 52 secondes. Le pic arteriel est egalement decale avec une difference moyenne de 28 secondes. Ceci s’explique d’une part par la meilleure resolution temporelle au scanner et d’autre part par le caractere non lineaire de l’augmentation de signal en IRM contrairement au scanner ou la densite ne depend que de la concentration en Iode. Conclusion Le type de courbe est identique entre les deux techniques d’imagerie contrairement au delai du pic tumoral.

Comment j’explore une tumeur des parties molles

Objectifs Connaitre la valeur des differents examens d’imagerie dans le bilan d’une tumeur des parties molles. Savoir optimiser la demarche diagnostique au sein d’une prise en charge multidisciplinaire. Savoir realiser un compte rendu coherent dans le bilan d’une tumeur des parties molles. Points cles Une analyse topographique precise est essentielle. Elle doit integrer la notion de compartiment. La cinetique de prise de contraste peut etre une aide a la caracterisation tissulaire. Le scanner multiphasique et les sequences 4D en IRM procurent des informations precises sur la topographie lesionnelle, la cinetique de prise de contraste et l’envahissement vasculaire. Un pic de choline en spectro-IRM oriente vers une tumeur maligne. Resume La prise en charge des tumeurs des parties molles depend de leur localisation et de leur caracterisation. Le bilan lesionnel doit preciser la localisation de la tumeur (compartiment, profondeur), sa taille, ses rapports (aponevrose, nerfs et vaisseaux, os), son agressivite et procurer des elements de caracterisation. La radiographie standard presente un interet limite mais elle reste pratiquee pour rechercher une extension osseuse ou montrer des calcifications lesionnelles. L’echographie est une technique difficile dans cette indication et les erreurs d’interpretation sont nombreuses. Elle se revele parfois utile en complement de l’IRM pour etudier l’angio-architecture tumorale. Le scanner multiphasique procure une analyse topographique precise, apporte des elements de caracterisation lesionnelle (calcifications, graisse, cinetique de prise de contraste, angio-architecture), fournit une cartographie vasculaire et permet de rechercher dans le meme temps des metastases pulmonaires. L’IRM represente la methode la plus performante pour caracteriser les lesions. Les sequences 4D apres injection IV de Gadolinium (TRICKS) fournissent de nombreux renseignements : topographie, cinetique de prise de contraste, envahissement vasculaire. Les sequences de diffusion pour differencier un oedeme medullaire reactionnel d’un envahissement tumoral de l’os sont a l’etude. La spectro-IRM est realisee en placant les voxels sur les zones se rehaussant le plus rapidement. La presence de choline est un argument en faveur d’un processus malin. Un controle histologique n’est pas necessaire dans les lipomes, MAV, hemangiomes et myosite ossifiante. Les biopsies radioguidees sont realisees en fonction de l’analyse compartimentale et de la voie d’abord chirurgicale, en visant les zones les plus actives de la tumeur.