James F. Griffith

Osteoporosis is associated with increased marrow fat content and decreased marrow fat unsaturation: A proton MR spectroscopy study

To use proton magnetic resonance spectroscopy (1H‐MRS) to evaluate vertebral marrow fat, and to determine whether bone density correlates with fat content and fat unsaturation levels in postmenopausal women.

Modified Pfirrmann grading system for lumbar intervertebral disc degeneration.

Study Design. A reliability study was conducted. Objective. To modify a grading system for lumbar disc degeneration and to test the reliability of this modified grading system. Summary of Background Data. The 5-level Pfirrmann grading system for disc degeneration did not prove discriminatory when used to assess disc degeneration in the elderly spine. Such discriminatory power is necessary to test the association between other variables and severity of disc degeneration. Methods. An 8-level modified grading system for lumbar disc degeneration was developed including a description of the changes expected for each grade and a 24-image reference panel. The reliability of the modified grading system was tested on 260 lumbar intervertebral discs in 52 subjects (26 men, 26 female) with a mean age of 73 years (range, 67–83 years). All examinations were analyzed independently by 3 readers. Intraobserver and interobserver reliabilities were assessed by calculating weighted kappa statistics. Results. On average, for all 3 readers, 0.39% of the 260 discs were classified as Grade 2, 22% were classified as Grade 3, 21.5% were classified as Grade 4, 25.3% were classified as Grade 5, 19.1% were classified as Grade 6, 7.1% were classified as Grade 7, and 4.8% were classified as Grade 8. Intraobserver agreement was excellent (weighted kappa range, 0.79–0.91) with substantial interobserver agreement (weighted kappa range, 0.65–0.67). Complete intraobserver agreement was obtained, on average, in 85% of all discs with 84% of disagreement being as a result of a 1 grade difference. Complete interobserver agreement was obtained, on average, in 66% of all discs with 91% of disagreement being as a result of a 1 grade difference. Conclusion. The modified Pfirrmann grading system is useful at discriminating severity of disc degeneration in elderly subjects. The system can be applied with good intra- and interobserver agreement.

A comparison of different imaging modalities and direct inspection after periosteal stripping in predicting the invasion of the mandible by oral squamous cell carcinoma

OBJECTIVE To compare the predictability of orthopantomograms (OPG), bone scans, computerised tomography (CT), magnetic resonance imaging (MRI) and periosteal stripping with direct inspection in predicting both the presence and extent of tumor invasion of the mandible. DESIGN Prospective study. SETTING Queen Elizabeth Hospital, Birmingham; Wordsley Hospital, Stourbridge; North Staffordshire Royal Infirmary, Stroke-on-Trent. SUBJECTS 35 consecutive patients requiring a mandibular resection as part of their treatment for oral squamous cell carcinoma. MAIN OUTCOME MEASURES The prediction of the extent of bone invasion for each of the investigations and direct inspection after periosteal stripping. The actual extent of invasion of the mandible from a detailed histological assessment. RESULTS The OPG underpredicted the width and depth of invasion by on average 13 mm and 2 mm. There were 5 false negative reports. Bone scans overpredicted the width and depth by 14 mm and 15 mm with 1 false negative. CT scans underpredicted the width of invasion by 5 mm and overpredicted depth by 3 mm, but 7 false negatives were returned. MRI scans overpredicted width and depth of invasion by 19 mm and 10 mm with 1 false negative. Direct inspection after periosteal stripping underpredicted the width and depth of invasion by 5 mm and 3 mm with 1 false negative. CONCLUSION OPGs and bone scans are useful for the initial assessment of all tumours in the region of the mandible. MRI is a more useful investigation than CT in the assessment of mandibular invasion by oral squamous cell carcinomas. Exploratory periosteal stripping at the time of resection can accurately predict the presence of tumour invading the mandible.

Compromised Bone Marrow Perfusion in Osteoporosis

A link between bone blood flow and osteoporosis may exist. Outside of the spine, the proximal femur is the most common site of osteoporotic fracture and is also an area prone to avascular necrosis and fracture nonunion. This study of the proximal femur investigates the relationship between BMD, bone marrow fat content, bone perfusion, and muscle perfusion. One hundred twenty healthy female subjects (mean age, 74 yr; age range, 67–89 yr) underwent DXA examination of the hip, proton MR spectroscopy, and dynamic contrast‐enhanced MR imaging of the right proximal femur, acetabulum, and adductor thigh muscle. In all bone areas examined (femoral head, femoral neck, femoral shaft, acetabulum), perfusion indices (maximum enhancement, enhancement slope) were significantly reduced in subjects with osteoporosis compared with subjects with osteopenia or normal BMD. Adductor muscle perfusion was not affected by change in BMD. As marrow perfusion decreased in the proximal femur, marrow fat increased (r = 0.827). This increase in fat content seemed to account for the decrease in marrow perfusion more than a reduction in BMD. For normal BMD subjects, perfusion parameters in the femoral head were one third of those in the femoral neck or shaft and one fifth of those in the acetabulum. Perfusion throughout the proximal femur is reduced in osteoporotic subjects compared with osteopenic and normal subjects. This reduction in perfusion only affects bone and not those tissues outside of bone with the same blood supply. As bone perfusion decreased, there was a corresponding increase in marrow fat.

Prevalence, Pattern, and Spectrum of Glenoid Bone Loss in Anterior Shoulder Dislocation: CT Analysis of 218 Patients

OBJECTIVE The purpose of our study was to determine the prevalence, pattern, and spectrum of glenoid bone loss in anterior shoulder dislocation, to relate this to the frequency of dislocation, and to test the appropriateness of the measurement method. SUBJECTS AND METHODS Two hundred eighteen patients with single or recurrent anterior shoulder dislocation underwent shoulder CT examination. Fifteen patients had bilateral dislocation. Prevalence and severity of glenoid bone loss and glenoid fracture were assessed. CT examinations of 56 control subjects without shoulder dislocation were evaluated for glenoid contour and side-to-side variation in glenoid width. RESULTS Glenoid bone loss was present in 27 (41%) of 66 patients with first-time unilateral dislocation and 118 (86%) of 137 patients with recurrent unilateral dislocation. Glenoid bone loss ranged from -0.3% to -33% (mean, -10.8% +/- 7.9%). Seventy-four (51%) of 145 patients had < or = 10% glenoid bone loss, 54 (37%) had between 10% and 20%, eight (6%) had between 20% and 25% glenoid bone loss, and nine (6%) had > or = 25% glenoid bone loss. Glenoid rim fractures were present in 49 (21%) of 233 dislocated shoulders. The number of dislocations correlated moderately with the severity of glenoid bone loss (r = 0.56). The normal side-to-side glenoid width variation was small (0.46 +/- 0.81 mm). CONCLUSION Glenoid bone loss is common in anterior shoulder dislocation. It is probably multifactorial in origin, is usually mild in degree, and has a maximum observed severity of -33%. Dislocation frequency cannot accurately predict the degree of bone loss.

Imaging of musculoskeletal tuberculosis: a new look at an old disease.

There are certain imaging features that help to differentiate tuberculosis from other bone and joint disorders with a similar presentation. The current authors discuss these distinguishing imaging features particularly with respect to ultrasound, computed tomography, and magnetic resonance imaging. The judicious and appropriate use of these newer imaging modalities coupled with aspiration or biopsy can lead to earlier recognition of musculoskeletal tuberculosis before the onset of debilitating disease.

Bone mass and architecture determination: state of the art

Bone fracture occurs when the bone strength (i.e. the ability of the bone to resist a force) is less than the force applied to the bone. In the elderly, falls represent the more severe forces applied to bone. Bone density is a good marker of bone strength, and has been used widely in this respect. Nevertheless, many aspects of bone strength cannot be explained by bone density alone. For this reason there has been increasing interest in studying architectural parameters of bone, beyond bone density, which may affect bone strength. Macro-architectural parameters include e.g. bone size and geometry assessed with techniques such as radiography, dual-energy x-ray absorptiometry (DXA), peripheral quantitative computed tomography (QCT), computed tomography (CT) and magnetic resonance imaging (MRI). Micro-architectural parameters include fine cortical and trabecular structural detail which can be evaluated using high-resolution imaging techniques such as multidetector CT, MRI, and high-resolution peripheral QCT. These techniques are providing a great deal of new information on the physiological architectural responses of bone to aging, weightlessness, and treatment. This will ultimately lead to the prediction of fracture risk being improved through a combined assessment of bone density and architectural parameters.

Bone marrow diffusion in osteoporosis: Evaluation with quantitative MR diffusion imaging

To determine the diffusion of vertebral body marrow with quantitative MR diffusion imaging and to examine whether differences exist between subjects with postmenopausal osteoporosis and premenopausal control subjects.

First‐time shoulder dislocation: High prevalence of labral injury and age‐related differences revealed by MR arthrography

To evaluate abnormalities and age‐related differences after first‐time shoulder dislocation.

Bone marrow fat content in the elderly: A reversal of sex difference seen in younger subjects

To investigate vertebral bone marrow fat content in elderly subjects related to sex, age, and bone mineral density (BMD) and relate these findings to published data in younger subjects.