Minoru Yamato

The relationship between facet joint osteoarthritis and disc degeneration of the lumbar spine: an MRI study

The role of MRI in assessing facet joint osteoarthritis is unclear. By developing a grading system for severity of facet joint osteoarthritis on MRI, the relationship between disc degeneration and facet joint osteoarthritis was determined. The accuracy of MRI in assessing facet joint osteoarthritis against CT was 94%. Under 40 years of age, the degree of disc degeneration varied among individuals. Over the age of 60, most of the discs were markedly degenerated. Under 40 years of age osteoarthritic changes in facet joints were minimal. Over the age of 60, variable degrees of facet joint osteoarthritis were observed but some facets did not show osteoarthritis. No facet joint osteoarthritis was found in the absence of disc degeneration and most facet joint osteoarthritis appeared at the intervertebral levels with advanced disc degeneration. Disc degeneration is more closely associated with aging than with facet joint osteoarthritis. The present study supports the hypothesis that “disc degeneration precedes facet joint osteoarthritis”, and also supports the concept that it may take 20 or more years to develop facet joint osteoarthritis following the onset of disc degeneration.

First histologically confirmed case of a classic chordoma arising in a precursor benign notochordal lesion: differential diagnosis of benign and malignant notochordal lesions

Abstract. The first histologically confirmed case of a classic chordoma arising in a precursor benign notochordal lesion is presented and the differential diagnosis between benign and malignant notochordal lesions is discussed. A 57-year-old man presented with a classic chordoma in the coccyx. The resected specimen demonstrated a small intraosseous benign notochordal lesion in the coccyx, which was adjacent to the classic chordoma. Also seen were two separate, similar benign lesions in the sacrum. The classic chordoma consisted of multiple lobules that were separated by thin fibrous septa and that showed cords or strands of atypical physaliphorous cells set within an abundant myxoid matrix. In contrast, the benign lesions consisted of intraosseous sheets of bland physaliphorous cells without any extracellular matrix. The affected bone trabeculae showed sclerotic reactions. It was concluded that benign and malignant notochordal lesions can be distinguished microscopically.

MRI of the knee in rheumatoid arthritis: Gd-DTPA perfusion dynamics.

Objective Seventeen knees in 13 patients with rheumatoid arthritis (RA) were studied with MRI to clarify the dynamics of Gd-DTPA administered intravenously and to determine an optimal imaging time. Materials and Methods Dynamic gradient recalled echo imaging with bolus intravenous injection of Gd-DTPA was performed following unenhanced T1− and T2-weighted SE imaging. Late-phase SE or serial gradient recalled echo images were obtained following dynamic study. Results There was rapid enhancement of synovium with maximal enhancement ratio of 96–499% (mean 214 ± 111%) with Tmax ranging from 120 to 660 s (mean 253 s). The synovial enhancement persisted over 80% of the peak enhancement for 6–27 min (average 12 min) with eventual enhancement of joint effusion from the periphery to the center beginning at 6 min to 8 min, 20 s after contrast medium injection. Complete enhancement of joint effusion was noted in four joints at 24–86 min. Conclusion We conclude that enhancement of synovium in patients with RA is a time-dependent phenomenon, and an optimal imaging time would be within 5 min following contrast medium administration.

Abnormal synovium in the frozen shoulder: A preliminary report with dynamic magnetic resonance imaging

We studied 16 patients (18 shoulders) with frozen shoulders, 8 patients with subacromial impingement syndrome, and 3 healthy volunteers with dynamic magnetic resonance imaging enhanced with gadolinium diethylenetriaminepentaacetic acid. After intravenous contrast was administered, gradient-recalled echo images were obtained in the oblique coronal plane every 11 to 13 seconds for a total period of 4 to 5 minutes. The signal intensity was measured at the periphery of the glenohumeral joint and in the subacromial bursa. The coefficient of enhancement (percent signal increase per second) in the frozen shoulders was 1.33 +/- 0.43 (mean +/- SD) for the glenohumeral joint and 0.89 +/- 0.47 for the subacromial bursa. These values were far greater than those in subacromial impingement syndrome or in the control group, indicating increased blood flow to the synovium in the frozen shoulders. No previous reports have shown a clinical measure related to the pathophysiology of this disease.

MR findings in iliotibial band syndrome

Abstract Objective. To elucidate the MR findings in iliotibial band (ITB) syndrome. Design and patients. The subjects comprised four patients (five knees) with lateral knee pain: two athletes and two non-athletes. One non-athlete was engaged in work requiring repetitive knee movement, and the other suffered from Cushing syndrome and had bilateral abnormalities. All patients were suspected of having a lateral meniscal tear prior to MR examination, but physical examination following provisional MR diagnosis warranted the final diagnosis. MR studies included fast spin echo sagittal imaging, fat-saturated fast spin echo proton density coronal imaging, and T2* radial imaging. Twelve normal volunteers were examined. Results and conclusion. Fat-saturated coronal imaging demonstrated an ill-defined, high-intensity area deep to the ITB. T2* radial imaging showed an identical, but less conspicuous, abnormality. The MR finding suggested soft tissue inflammation and/or edema rather than focal fluid collection in the bursae. The signal alteration predominated in the region beneath the posterior fibers of the ITB, thus supporting the current opinion that the posterior fibers of the ITB are tighter against the lateral femoral epicondyle than the anterior fibers. The ITB itself did not show any signal alteration or increased thickness.

Trabecular trauma of the talus and medial malleolus concurrent with lateral collateral ligamentous injuries of the ankle: evaluation with MR imaging

Abstract Objective. The objective of this study was to elucidate the relationship between lateral collateral ligamentous injuries of the ankle (ankle sprain) and bone bruise (trabecular trauma) of the talus and/or malleoli in the patients with twisting injuries of the ankle. Design. Magnetic resonance studies of the ankle were retrospectively reviewed, focusing on the presence or absence of lateral collateral ligamentous injuries and the location of bone bruise in the talus and/or malleoli. Patients. Thirty-five patients with acute twisting injuries of the ankle were studied. Results and conclusion. Four patterns of bone bruise were found in 14 patients: (1) bone bruise in the talar dome equivalent to osteochondral fracture in two patients, (2) bone bruise in the posteromedial aspect of the talus and the medial malleolus singly or in combination in four, (3) bone bruise in the anteromedial aspect of the talus in six, and (4) bone bruise with a combination of the second and third patterns in two. The second pttern was associated with tear of the anterior talofibular (ATAF) ligament in all patients and injury of the calcaneofibular (CF) ligament in one out of four. The third and fourth patterns were associated with tears of both ATAF and CF ligaments in all patients. The identification of bone bruise was of value in indicating lateral collateral ligamentous injuries.

Intertrabecular pattern of tumors metastatic to bone

The prevalence of radiologically invisible metastatic tumors to bone is not known. To clarify this, the authors examined histologic sections, radiographs, bone scans, and magnetic resonance (MR) images of autopsied patients with bone metastases.

Septic arthritis of a lumbar facet joint: report of a case with early MRI findings.

A 56-year-old man was hospitalized with a 2-day history of back pain and fever. A magnetic resonance (MR) scan taken on admission showed a facet joint effusion and soft-tissue abnormality posterior to the joint. Follow-up MR imaging confirmed the facet joint destruction and periarticular abscess. A biopsy specimen grew Staphylococcus aureus. MR imaging is helpful in detecting this rare infection in the earliest phase of the disease.

Fragile bone syndrome associated with craniognathic fibro-osseous lesions and abnormal modeling of the tubular bones: report of two cases and review of the literature.

Abstract Objective. To report examples of disorders characterized by bone fragility, calvarial and/or gnathic fibro-osseous lesions, and metadiaphyseal undermodeling of the tubular bones. Design. The clinical, radiological, and pathological features of two patients are described and the literature reviewed. Patients. The patients comprised a 10-year-old boy and a 48-year-old woman. The former exhibited multiple fractures starting in early childhood and calvarial masses which developed in late childhood; the latter showed a mandibular mass. Results. Calvarial doughnut lesions, osteopenia with coarse bony trabeculae, and undermodeling of the lower limbs were radiologically demonstrated in the first patient, while multiple sclerotic foci in the maxilla and mandible, spontaneous bowing of the right femur, and minimal undermodeling of the tibiae were demonstrated in the second. Bone biopsy of the iliac crest in the first patient revealed histologically normal bony trabeculae. Bone histomorphometry suggested an increased osteoid surface. Osteoid volume was also slightly increased. The pathological findings of the mass in the jaw in the latter patient were consistent with it being a fibro-osseous lesion. The literature review revealed several patients whose features overlapped with those of our patients. Conclusion. These patients may represent a group of fragile bone syndromes which differ from osteogenesis imperfecta.

Calcified leiomyoma of deep soft tissue in a child

Abstract We report the case of a 7-year-old boy with a calcified leiomyoma in the right gluteal muscle. Radiography and CT showed a well-defined soft tissue mass with mulberry-like calcifications that superficially resembled chondroid matrix calcification. The mass exhibited high-signal intensity intermingled with spotty low-signal intensity on T2-weighted MRI which was attributable to extensive non-malignant degeneration of the tumour.