F. Machiels

MR imaging of meniscal cysts: evaluation of location and extension using a three-layer approach.

PURPOSE To analyze the extension of medial and lateral meniscal cysts relative to the capuloligamentous planes of the knee. MATERIALS AND METHODS The MR images of 32 patients with meniscal cysts were reviewed. The location and extension of the meniscal cysts with reference to the capsule and ligaments were recorded. RESULTS Most medial meniscal cysts were located posteromedially. Posteromedial meniscal cysts usually penetrated the capsule and were located between layer I and the fused layers II+III. From this site some extended anteriorly and then became located superficial to the superficial MCL. The location of lateral meniscal cysts was more varied. Anteriorly the cysts were located deep to the iliotibial band, whereas posterolateral cysts were located deep to the lateral collateral ligament. CONCLUSION Although the site of capsular penetration of meniscal cysts is determined by the location of meniscal tears, the possible pathways of extension appear to be determined by the capsuloligamentous planes of the knee.

Can bone marrow edema be seen on STIR images of the ankle and foot after 1 week of running

PURPOSE To evaluate whether initiation of running in sedentary individuals would lead to bone marrow edema on MR images, within the time span of 1 week. MATERIALS AND METHODS The feet of 10 healthy volunteers were imaged by MR imaging before and after running during 30 min a day for 1 week. The images were evaluated by consensus of 2 musculoskeletal radiologists who graded the presence of bone marrow edema on a 4-point scale. Edema scores and number of bones involved before and after running were compared statistically. RESULTS Edema was present on the baseline images in 3 subjects. After running edema showed an increase or was present in 5 subjects. The changes after running were statistically significant. Bones involved were the talus, calcaneus, navicular bone, cuboid bone, and 5th metatarsal. CONCLUSION Edema patterns can be seen in the feet of asymptomatic individuals. During initiation of running an increase of edema or development of new edema areas can be seen.

Subcutaneous granuloma annulare: MR imaging findings.

Abstract We present a case of subcutaneous granuloma annulare evaluated with MR imaging. The mass was poorly defined and showed thickened interconnecting strands with low signal intensity on T1- and T2-weighted MR images. When a poorly defined subcutaneous mass with low signal intensity on both T1- and T2-weighted MR images is observed in an otherwise healthy child, subcutaneous granuloma annulare should receive serious consideration. Subcutaneous granuloma annulare should be added to the list of tumors with short T2.

Deep benign fibrous histiocytoma of the knee: CT and MR features with pathologic correlation

Abstract. Magnetic resonance imaging and pathologic findings in a 28-year-old patient with a giant deep benign fibrous histiocytoma in the popliteal fossa of the right knee are described. The MR imaging findings include a well-delineated oval mass with low signal intensity on T1-, and high signal intensity on T2-weighted, images, and marked peripheral contrast enhancement. To the best of our knowledge, this is the first report on the MR findings in this entity.

Imaging in sportsmedicine—knee

Abstract Since the last decade, the introduction of Magnetic Resonance Imaging has provided a powerful new tool for the clinician to diagnose sports-related knee injuries. The main objective of this paper is to familiarise the relevant specialists with the proven clinical indications and semiology of MRI of the knee. At the present time, the knee joint is the area in which the advantages of MRI are most spectacularly apparent. The MR appearances of meniscal tears in particular, are first discussed in detail, referring to recent literature and personal experience based on more than then thousands MR examinations of traumatic knees. Also the mechanisms of injuries and the most commonly involved sports are described. The precise types of meniscal lesions, as visualised at arthroscopy, are abundantly illustrated on MR images: e.g., bucket-handle, radial and horizontal cleavage tears, meniscocapsular separations, discoid menisci and meniscal cysts. We discuss the numerous pitfalls due to neighbouring anatomical structures as well as non clinically or surgically significant intrameniscal hypersignals in athletes. Towards other imaging techniques, MRI is particularly suited for the diagnosis of ligamentous injuries, especially the cruciate ligaments. We develop the currently used direct and indirect signs of rupture, the diagnostic difficulties related to the age of trauma and the detection of associated lesions. Sport-induced tendinous and bursal pathology is another interesting indication of MRI, not only lesions of the more superficial extensor tendons but also the pes anserinus or hamstring tendons. We finally treat the recent developements of MRI in assessement of cartilage, subchondral and medullary bone disorders of traumatic or microtraumatic origin.

Meniscal tears: comparison of half-Fourier technique and conventional MR imaging

PURPOSE To determine whether half-Fourier MR image acquisition technique can provide similar information to that of conventional MR acquisition technique for evaluation of meniscal tears. MATERIALS AND METHODS We studied 101 menisci in 52 patients who were referred for evaluation of meniscal tears. Sagittal MR images of the knee were obtained for all patients by using proton density and T2-weighted SE sequences on a 1-T clinical system. The half-Fourier technique and conventional technique were used for all patients. All other imaging parameters were identical for both sequences (TR/TE=2400/20,70; 3 mm slice thickness; 200 x 256 matrix; field of view, 200; one signal acquired). Both sets of images were filmed with standard window and level settings. Images were randomised and interpreted independently by two radiologists for the presence of meniscal tears. Images were also subjectively assessed for image quality using a five-point grading scale. RESULTS On half-Fourier images, Reader 1 interpreted 23 menisci as torn, compared to 28 for Reader 2. On conventional images, Reader 1 interpreted 24 menisci as torn, compared to 26 for Reader 2. Agreement between interpretation of the conventional and that of the half-Fourier images was 99% for Reader 1, and 98% for Reader 2. Agreement between readers for the half-Fourier images was 95%, and for the conventional images 96%. No statistically significant difference was found in the subjective evaluation of image quality between the conventional and half-Fourier images. CONCLUSION The half-Fourier acquisition technique compares favourably with the conventional technique for the evaluation of meniscal tears.