Rafaela Soler

Magnetic resonance imaging of pyomyositis in 43 cases

PURPOSE To describe the magnetic resonance imaging (MRI) findings in pyomyositis. METHODS AND MATERIALS Forty-three patients with proven muscle infection (30 males, 13 females) ranging in age from 14 to 86 years (mean 42 years) were studied with MRI. The initial clinical diagnose were soft tissue infection (n=27), neoplasm (n=12), thrombophlebitis (n=3), and lymphedema (n=1). Spin-echo T1- and T2-weighted images were obtained in all cases and STIR sequence in 6. Spin-echo T1-weighted images after Gd-DTPA injection were obtained in 16 cases. The signal intensity findings, the extent of the abnormalities in the soft tissue (muscle, fascial and subcutaneous involvement), the presence of fluid collections, and the involvement of neighbouring bone and joint were reviewed retrospectively. RESULTS A hyperintense signal on T2-weighted and STIR images were detected in all patients. Fluid collections were seen in 21 cases as localized areas of hypointensity on the T1-weighted images, and highly hyperintense areas on the T2-weighted images. In four patients a rim of high signal intensity was seen around the fluid collection on the T1-weighted images. On contrast-enhanced T1-weighted images there was diffuse enhancement in the patients without fluid collections that was heterogeneous in seven and homogeneous in two. After Gd-DTPA all fluid collections showed a central area without enhancement and a well-defined enhancing peripheral rim. Involvement of adjacent structures included subcutaneous tissue (n=25), bone marrow (n=14), fascial planes (n=15) and joints (n=11). CONCLUSION MRI is useful in the assessment of pyomyositis and in determining the location and extension. A hyperintense rim on unenhanced T1-weighted images and peripheral enhancement after Gd-DTPA are useful for identifying the number, size, and location of soft-tissue abscesses.

MRI of subendocardial perfusion deficits in isolated left ventricular noncompaction.

Ventricular noncompaction is a rare unclassified cardiomyopathy due to intrauterine arrest of compaction of the loose interwoven meshwork. It is characterized by markedly irregular endocardial surfaces with prominent trabeculations and intertrabecular recesses. Patients are asymptomatic or present with depressed ventricular function, ventricular arrhythmia, and systemic embolism. Areas of restricted myocardial perfusion have been previously documented by scintigraphy and positron emission tomography. This report documents a case of isolated left ventricular noncompaction with subendocardial perfusion deficits on MRI.

Lipoma arborescens of the knee: MR characteristics in 13 joints.

UNLABELLED Lipoma arborescens (LA) is a rare, poorly understood intraarticular lesion, with few cases reported in the imaging literature. Our purpose was to describe on MR the different morphologic appearances of LA of the knee and to investigate the incidence of associated anomalies. METHOD The medical records and MR findings of 12 patients with proven LA in 13 knee joints were retrospectively reviewed with particular emphasis on the shape of the lesion, location, signal intensity, and past clinical history. RESULTS We found three common morphological patterns of presentation: multiple villous lipomatous synovial proliferations (n = 6), isolated frond-like fat subsynovial mass (n = 2), and mixed pattern (n = 5). Multiple villous lipomatous synovial proliferations and mixed pattern were usually associated with a history of trauma and/or chronic inflammatory diseases. However, the least frequent isolated frond-like fat subsynovial mass appears to originate without antecedent. The durations of symptoms were 1-7 months (multiple villous lipomatous synovial proliferations), 1-20 years (mixed pattern) and 6-7 years (isolated frond-like subsynovial fat mass). CONCLUSION Our study suggest that LA can present with a variety of morphological appearances on MR that may depend on the previous clinical history and duration of the disease.

Magnetic resonance imaging of delayed enhancement in hypertrophic cardiomyopathy: relationship with left ventricular perfusion and contractile function.

Purpose: The aim of the study was to analyze the relationship between myocardial delayed enhancement, first-pass perfusion, and contractile function in hypertrophic cardiomyopathy (HCM) patients, using MR. Methods: Fifty-three patients diagnosed with HCM were prospectively examined using a 1.5-T MR unit. Multiphase gradient-echo sequences were performed to study global left ventricular function, wall thickness, and left ventricular mass. Myocardial tissue tagging was conducted to evaluate contractile function. T1-weighted inversion-recovery sequences were obtained at rest to study myocardial contrast enhancement at first pass and delayed enhancement 10 minutes later. Results: Delayed enhancement found in 30 patients (56.6%) was most commonly seen in hypertrophic segments. Nine patients exhibited delayed enhancement in segments with normal wall thickness (<15 mm). Sixteen patients (30.1%) showed first-pass perfusion defects at rest, which were associated with significantly lower stroke volume (P < 0.05) and lower cardiac output (P < 0.01). The hypokinetic segments found in 16 patients (30.1%) were significantly thicker at end diastole (P < 0.01). Delayed enhancement correlated positively with perfusion defects (r = 0.5, P < 0.01) and hypokinetic segments (r = 0.3, P < 0.05). Conclusion: Delayed myocardial enhancement is most commonly found in hypertrophic segments but also can be seen in segments with normal wall thickness. Perfusion defects at rest and impaired contractile function are related abnormalities with delayed myocardial enhancement. Further studies are necessary to assess the role of myocardial tagging, first-pass perfusion, and delayed enhancement in risk stratification for patients with HCM.Abbreviations: MCH = hypertrophic cardiomyopathy, FOV = field of view

Magnetic resonance imaging of congenital abnormalities of the thoracic aorta

Abstract. This article outlines the ability of MR imaging in the detection and presurgical evaluation of congenital abnormalities of the thoracic aorta (CATA). Congenital abnormalities of the thoracic aorta may be found incidentally on chest radiographs in patients without symptoms, or it can be associated with clinical findings which are very variable depending on the association with congenital cardiac malformations or vascular ring. When CATA is suspected as the cause of anomalies in the mediastinum in asymptomatic patients, confirmation of the abnormality should be by MR imaging allowing precise evaluation of the thoracic aorta and origin of the principal arteries. When CATA is considered because clinical findings indicate coarctation of the aorta, vascular ring or associated cardiac disorder, evaluation with ultrasound can be complemented by MR, which in most cases will replace the diagnostic catheterization.

MRI of musculoskeletal extraspinal tuberculosis.

Purpose The aim of this study was to describe the MR findings in extraspinal musculoskeletal tuberculosis (EMT). Method A retrospective review was conducted of the MR findings of 18 patients with microbiologically and/or pathologically proven EMT. All MR studies were performed using T1-and T2-weighted spin echo sequences. T1-weighted spin echo sequences after Gd-DTPA injection were obtained for 12 patients. The MR images were evaluated for abnormalities in joints, bones, and soft tissues, and the results were grouped by anatomic localization, frequency distribution of structures affected, and morphologic patterns of involvement. Results Isolated soft tissue tuberculosis was found in 10 (55.5%) patients and involvement of more than one structure in 8 (44.4%). Pyomyositis (n = 6) and arthritis with involvement of adjacent soft tissues (n = 7) were the most common forms of presentation. One patient presented with isolated fascial superficial tissue involvement in one leg. Isolated pyomyositis involving one (n = 3) or two (n = 3) muscles was homogeneous in six cases and showed intermediate (n = 6), low (n = 2), or high (n = 1) signal intensity on T1-weighted images and a high and very hyperintense signal on T2-weighted images. The tenosynovitis synovial fluid was homogeneous (n = 1) or heterogeneous with multiple tiny hypointense nodules (n = 1) on T2-weighted images. The subdeltoid bursitis fluid was characterized by homogeneous low signal intensity with a hyperintense rim (n = 2) on T1-weighted images and homogeneous (n = 1) or heterogeneous hyperintense signals with areas of low signal intensity (n = 1) on T2-weighted images. In tuberculous arthritis, the synovial joint fluid (n = 7) showed heterogeneous (n = 4) or homogeneous (n = 3) low signal intensity on T1-weighted images and high or very high signal intensity on T2-weighted images. Where involved, the adjacent muscle(s) (n = 8) were usually hypointense on T1-weighted images and very hyperintense on T2-weighted images. Associated cellulitis was found in arthritis with involvement of neighboring soft tissues (n = 5), pyomyositis (n = 2), and tenosynovitis (n = 1). The images obtained after Gd-DTPA showed peripheral (n = 10) or heterogeneous (n = 1) enhancement or no enhancement (n = 1). Conclusion The MR findings for EMT are variable. Although diagnosis is dependent largely on prior presumption and clinical context, MRI provides valuable guidelines in defining the extent of the lesions to select the appropriate treatment and for follow-up of abnormalities.

Elastofibroma Dorsi: MR and CT findings

Elastofibroma dorsi is a benign, pseudotumoral soft tissue lesion of the periscapular area. The characteristical findings in magnetic resonance images and computed tomography usually allow the diagnosis and prevent radical surgery. We report the MR and CT findings of elastofibroma dorsi in four women presenting as an elongated soft tissue mass intermingled with fat, between the ribs and the serratus muscle, deep to the inferior angle of the scapula.

Significado clínico del realce tardío de gadolinio con resonancia magnética en pacientes con miocardiopatía hipertrófica

Introduccion y objetivos La fibrosis miocardica puede ser detectada en la miocardiopatia hipertrofica (MCH) mediante resonancia magnetica cardiaca (RM) con realce tardio de gadolinio (RT). Analizamos la relacion entre la extension del RT y la morfologia y funcion del ventriculo izquierdo (VI) y los datos clinicos. Metodos Estudiamos con RM a 104 pacientes diagnosticados de MCH. Se obtuvieron secuencias de cine-RM y secuencias de realce tardio. Resultados Cincuenta pacientes presentaron RT (48%; rango: 1-11 segmentos). La extension del RT se correlaciono positivamente con el grosor maximo (r = 0,53; p Conclusiones La extension del RT refleja una mayor expresion de esta enfermedad. Se asocia con un dano miocardico mas severo (menor fraccion de eyeccion y mayor numero de segmentos hipocineticos) y con parametros clinicos adversos (edad mas joven en el momento del diagnostico, hipertrofia severa, TVNS y respuesta isquemica al ejercicio), lo que indica que podria vincularse al pronostico.

Hemophilic arthropathy. A scoring system for magnetic resonance imaging

Abstract. The aim of this study was to define a system for scoring hemophilic arthropathy (HA) based on MR findings, providing for objective evaluation of the degree of joint involvement and evolution after on-demand administration of FVIII substitutional therapy or prophylactic treatment. A total of 133 MR examinations (89 basal and 44 during follow-up) were performed in 25 patients. Patients were divided in two groups depending on the therapy received and the length of time that the disease had been evolving at the start of the study. Group I was composed of 10 patients with secondary prophylaxis and group II was composed by 15 treated on demand. T1-weighted and T2*-weighted images performed on a 0.5-T unit were prospectively evaluated. The joint involvement was established on a scale of 0 (no abnormalities), I (minimal amount of hemosiderin), II (large amount of hemosiderin and isolated cartilaginous erosion), III (cartilage destruction, bone erosions, and subchondral cysts) to IV (large internal joint derangement, secondary osteoarthritis and/or ankylosis). At basal MR examination, patients of group I showed no abnormalities (n=28, 75.6%), grade I (n=3), and grade II (n=6) of HA. Patients of group II corresponded to MR grades III (n=21) and IV (n=11) of HA. The MR follow-up showed improvement in three joints of group I and worsening in 5 joints in group I and 2 joints in group II. Early signs of HA were detected in 10 joints with MR imaging but were underestimated on plain radiographs. Advanced degrees of HA were classified as severe under both imaging techniques. Magnetic resonance is the preferred imaging technique to assess HA. The earliest signs of joint damage, detected by MR, are overlooked by plain radiography. The MR scoring system can be used for evaluating HA. Follow-up MR should be performed to evaluate regression or worsening of the abnormalities, primarily in the case of patients with prophylaxis who usually suffer normal or early joint involvement not detected by other means.

Fibrosing mediastinitis: CT and MR findings

The aim of this study is to present the computed tomography (CT) and magnetic resonance (MR) findings in three cases of fibrosing mediastinitis, probably secondary to tuberculosis. Two patients had diffuse involvement of the mediastinum and one patient presented with a posterior mediastinal mass. On CT, the patients with diffuse involvement showed infiltrating soft-tissue masses with multiple foci of dense calcifications. One of these lesions enhanced mildly with contrast and one did not enhance. On MR examination, diffuse masses were of heterogeneous, intermediate and low signal on T1-weighted images (n = 2) and were of homogeneous low signal (n = 1) or heterogeneous (n = 1) signal intensity on T2-weighted images. After administration of Gd-DTPA, these mediastinal masses showed heterogeneous enhancement. The posterior mediastinal mass showed homogeneous pronounced enhancement on CT and was homogeneous with intermediate T1 signal intensity and hypointense T2 signal intensity. The CT findings of an infiltrative or well-defined mediastinal mass with scattered calcifications should suggest the diagnosis of fibrosing mediastinitis in the appropriate clinical setting. Although the appearance of calcification on MR are not specific, this technique provides further information than CT especially in those cases in which the lesions appear noncalcified, because MR imaging revealed areas of low signal intensity characteristic of fibrous tissue.