REGISTRIES AND CARE OF NEUROMUSCULAR DISORDERS: P.291Clinicopathological study for ultrasound-guided biopsy cases using linear probe

Abstract

Muscle ultrasound is a non-invasive technique to detect neuromuscular disorders. Large myopathological findings including fibrosis, fatty infiltration, and inflammation increase muscle echo intensity, which can be used to delineate normal from diseased muscle. But, the association between ultrasound findings and myopathological findings such as nemaline rods, ragged red fibers, and rimmed vacuoles are not clarified. Linear transducer can describe small size findings more easily than convex or sector transducers, so we can detect these small size findings. In this study, we aimed to describe the association between myopathological findings and ultrasound imaging produced by linear transducers. We examined 45 consecutive cases with ultrasound images and muscle pathology findings. Their biopsy sites were selected by MMT scores and muscle CT/MRI findings. Ultrasound examinations were performed by using SSA-640A ultrasound imaging system (Toshiba, Tokyo, Japan) with 15MHz linear transducer. Ultrasound images were evaluated by Heckmatt score. After their ultrasound examinations, we performed open muscle biopsies assisted by ultrasound findings. Each pathological finding described by hematoxylin and eosin and modified Gomori stainings was classified in four categories; none, mild moderate, severe. Patients with Heckmatt score 1 images had almost normal findings. Mild endomysial fibrosis, fiber size variation, endomysial lymphocyte infiltration, cytoplasmic structures including nemaline rods, ragged red fibers, and rimmed vacuoles were scattered in 70% of patients with score 2 images. Perimysial fibrosis and fatty tissue were observed in 50% of score 3 patients. 70 % of patients with score 4 images had severe fatty tissue and grouped atrophy. Lymphocyte infiltrations decreased in score 4 cases. In addidion, score 4 cases with inflammatory myopathies show same severities of fibrosis and fatty tissues as score 2 and 3 cases, and less frequently than score 4 cases of previous report (p<0.01). Linear transducer could detect smaller myopathological findings.