Quantitative computed tomography of spine: comparison of three-dimensional and two-dimensional imaging approaches in clinical practice.

Quantitative computed tomography (QCT), a widely utilized technique for determining bone mineral density (BMD) at various skeletal sites, may yield less precise measurements if there are operator measurement errors and other technical variables. Two-dimensional (2D)and three-dimensional (3D)QCT scans of the lumbar spine of 21 women were compared in order to investigate the effects of potential operator variability on the precision of BMD measurements and to examine resulting differences of these imaging approaches in clinical practice. No significant difference was found (p > 0.05) in precision between the 2D and 3D QCT BMD measurements owing to operator measurement errors on the CT scans. The variability in BMD values within numerous small regions of interest (ROIs)( approximately 75 mm (2) ) of cancellous bone within a single vertebra was 10.1%, larger than the 2D or 3D BMD variability measured in typical regions ( approximately 250 mm (2)) by an order of magnitude. 3D BMD values in this population, which represented a wide range of clinical values, were found to be significantly greater than 2D BMD values by an average of 5.6% (p = 0.00024) relative to the 2D QCT values. Our findings suggest technical measurement error does not have a significant effect on precision of BMD measurements obtained with either QCT method. Several factors, however, including the incorporation of focal regions of higher density bone mass within the 3D QCT ROI may account for the higher BMD values compared with those for 2D QCT.

Hand ultrasound for osteoporosis screening in postmenopausal women.

There is a need for low-cost screening methods to detect low bone mass (osteopenia or osteoporosis) in postmenopausal women. The utility of quantitative ultrasonography (QUS) of the hand was assessed for osteoporosis screening using the WHO criteria. Bone mineral density (BMD) was measured in 206 postmenopausal Mexican-American women at the total hip and lumbar spine by dual-energy X-ray absorptiometry (DXA). The amplitude-dependent speed of sound (AD-SoS) was measured in the phalanges by QUS. Subjects identified by DXA as having osteopenia or osteoporosis had significantly lower AD-SoS values in comparison with normals. Estrogen users had significantly higher spine and hip BMD and AD-SoS values compared with non-estrogen users. The areas under the receiver operating characteristic (ROC) curves (AUC) for AD-SoS to screen for osteoporosis (T-score < or = -2.5) at the spine or hip were 0.73 for all subjects, 0.74 for estrogen users and 0.68 for non-estrogen users. The AUC for non-estrogen users to screen for osteopenia (T-score -1 to -2.5) was 0.77. Performance comparisons of AD-SoS with SCORE (a risk factor questionnaire) and body weight showed AUC values of 0.73, 0.69 and 0.65, respectively. QUS was the superior screening test when considering both the AUC and the shape of the ROC curves. For non-estrogen users, the group at higher risk for osteoporosis, QUS correctly identified 31% as normal, and 62% as having low bone mass and needing DXA referral; and the remaining 7% were false negatives. These data suggest phalangeal QUS can be effectively used for screening osteoporosis in postmenopausal women.

Low levels of estradiol are associated with vertebral fractures in older men, but not women: the Rancho Bernardo Study.

This longitudinal study included 288 postmenopausal women without estrogen use (median age, 72 yr) and 352 men (median age, 66 yr). All were community-dwelling, ambulatory, and Caucasian. Blood for hormone assays (total and bioavailable estradiol and testosterone, estrone, androstenedione, dihydrotestosterone, dehydroepiandrosterone, and dehydroepiandrosterone sulfate) was obtained in 1984-1987, and vertebral fractures were diagnosed from lateral spine radiographs obtained in 1992-1996. At least one vertebral fracture was found in 21% of women and 8% of men. Among men, age-adjusted hormone levels differed by fracture status only for total (64.1 vs. 75.4 pmol/L, P = 0.012) and bioavailable (43.0 vs. 51.4 pmol/L, P = 0.008) estradiol. There was a graded association between higher concentrations of total and bioavailable estradiol and lower fracture prevalence (trend P<0.01 for both hormones). Men with total testosterone levels compatible with hypogonadism (<7 nmol/L) were not more likely to have vertebral fractures. In women, none of the measured sex hormones was associated with vertebral fractures. There was also no increased prevalence of fractures in women with estradiol levels below the assay sensitivity (<11 pmol/L). These data suggest that estrogen plays a critical role in the skeletal health of older men and confirm other studies showing no association of postmenopausal endogenous estrogen levels with vertebral fractures in older women.

Quantitative computed tomography in the evaluation of spinal osteoporosis following spinal cord injury.

Disuse osteoporosis occurs in the lower extremities of patients with spinal cord injury (SCI). However, spinal osteoporosis is not usually observed in these patients. We investigated lumbar spine bone mineral density (BMD) in SCI patients using single energy quantitative computed tomography (QCT) and dual-energy X-ray absorptiometry (DXA). Our study population consisted of 64 patients with long-standing SCI. Spine BMD (g/cm3) was assessed by QCT at four vertebrae ranging from T11 to L4 with single mid-vertebral CT slices 1 cm thick parallel to the vertebral end-plates. Confounding variables affecting normal trabecular bone pattern, such as compression fractures, surgical hardware or fat replacement, were excluded. For a subset of 29 patients, DXA values of the spine and femoral neck were also measured, and QCT and DXA Z-scores were compared On the average, the 64 SCI patients had Z-scores 2.0 +/- 1.2 below those of age-matched controls. In the subset of 29 patients with both QCT and DXA measurements, the QCT and DXA Z-scores were 2.4 +/- 1.1 below and 1.3 +/- 2.3 above the mean, respectively (p < 0.0001). Our results indicate that QCT reveals osteoporosis of the spine after SCI, in contrast to DXA. We postulate that QCT is more valuable for evaluating spinal osteoporosis following SCI than DXA and thus recommend QCT for spinal BMD studies in SCI.

Delayed diagnosis of primary non-Hodgkin's lymphoma of the sacrum.

Primary non-Hodgkin's lymphoma of bone is a rare, malignant hematologic tumor affecting most commonly persons in the fourth decade of life. The tumor produces predominantly osteolytic lesions usually in the femur and pelvic bones and, very rarely, may present with spinal epidural involvement. The authors discuss an interesting case of primary non-Hodgkin's lymphoma of bone involving the sacrum with epidural invasion, in which the atypical imaging findings along with negative biopsy results delayed diagnosis.

Femoral anteversion and neck-shaft angle in children with cerebral palsy.

A database of femoral anteversion and neck-shaft angle was compiled of measurements made by the trigonometric fluoroscopic method of 147 patients (267 hips) with cerebral palsy. The angles of femoral anteversion were similar at early ages between healthy children and children with cerebral palsy. However, as the age of the children increased, those with cerebral palsy showed little change in anteversion angle, whereas the healthy children had progressively decreasing angles of femoral anteversion as they approached adulthood. The neck-shaft angle was increased significantly in children with cerebral palsy compared with the angles of healthy children. Patients who were ambulatory were shown to have an increased angle of femoral anteversion and a decreased neck-shaft angle compared with nonambulatory patients. There was no significant difference in angles among the various distributions of involvement, including patients with diplegia, hemiplegia, and quadriplegia.

MR imaging of tears of discoid lateral menisci.

OBJECTIVE: The purpose of this study was to determine the positive predictive value (PPV) for diagnosis of discoid lateral meniscal tear using MR imaging and to describe various patterns of such tears in the knee. SUBJECTS AND METHODS: MR reports of 77 patients (10-67 years old) who underwent prospective MR imaging that led to a diagnosis of discoid lateral meniscal tear were correlated with arthroscopic results. MR images obtained in 71 patients confirmed to have discoid lateral meniscial tear were retrospectively reviewed for the presence, site, and pattern of discoid lateral meniscal tear, including type of displacement of the torn segment. MR abnormalities were correlated with arthroscopic findings. RESULTS: For the prospective MR interpretations, the PPV for discoid meniscus was 92%. PPV for discoid meniscal tear was 57%. PPVs for individual types of discoid meniscal tears were 46% (peripheral tear, 19/41), 76% (peripheral tear with horizontal tears, 16/21), 56% (horizontal tear, 5/9), 50% (transverse tear, 1/2), 67% (horizontal tear combined with transverse tear, 2/3), and 100% (longitudinal tear, 1/1). Peripheral tear alone and peripheral tear with horizontal tear were the most common types of tears (n = 20, 28%). Multiple tears (n = 34, 48%) were common. Displacement of the torn segments was seen in 51 patients (72%). CONCLUSION: MR imaging has a low PPV for diagnosing discoid lateral meniscal tear. Peripheral tear alone and peripheral tear with horizontal tear were the most common types of tears, and displacement of the torn segment was frequent.

Influence of heterotopic ossification of the hip on bone densitometry: a study in spinal cord injured patients.

OBJECTIVE: To evaluate (1) the magnitude of falsely elevated bone density results caused by heterotopic ossification (HO) around the hip and (2) effect of age of patients when the measurement was taken, age of patients at injury, and age of injury (time since event) to the prevalence of HO. SUBJECTS AND METHODS: We blindly analyzed plain radiographs of the hip [(obtained within 1 month of dual energy X-ray absorptiometry (DEXA)] in 107 spinal cord injured (SCI) patients for HO and matched the result to the three regions of interest (ROI): the femoral neck, Ward's triangle, and the trochanter. The influence of HO on bone densitometric values was determined by the analysis of variance (ANOVA) and post-hoc analysis. RESULTS: Nineteen (18%) patients had HO; overlying the femoral neck (79%), trochanter (74%) and Ward's triangle (37%), respectively. Significant elevation of densitometric values (P < 0.05 or less) was observed in a various magnitude at each ROI, with the greatest elevation at Ward's triangle. The prevalence of HO was high when the patients were injured at age range of 20-39 years. CONCLUSIONS: HO around the hip can cause significantly elevated bone densitometry results at all ROIs, which can obscure underlying osteoporosis, leading to underestimation of fracture risk. Determination of bone density in this region with corresponding plain radiographs would be of help. In SCI patients, prevalence of HO was high when the age of patients at injury was 20-39 years.

[The imaging of hamate fractures in the conventional X-ray and CT: experimental results and clinical experiences]. / Darstellung von Os hamatum-Frakturen im konventionellen Röntgenbild und CT: experimentelle Ergebnisse sowie klinische Erfahrungen.

PURPOSE: Examination of the ability to image fractures of the body and hook of the hamate bone in conventional X-rays and HR-CT. MATERIAL AND METHODS: In an in vitro experiment on 18 cadaver hands, the hamate bone was fractured at different localisations. Before and after fracture, conventional x-rays were taken in different projectional planes: a.-p., lateral, oblique and carpal tunnel view, as well as an HR-CT with 2 mm layer thickness in the axial, sagittal and coronal plane. In addition, 15 clinically verified hamate bone fractures (two body and 13 hook of hamate fractures) were reviewed retrospectively to assess the value of the imaging procedures that led to diagnosis. RESULTS: Taking into account all conventional x-ray projections applied, the in vitro experiment yielded a sensitivity of 72.2%, a specificity of 88.8% and an accuracy of 80.5%. For CT, the sensitivity was 100%, the specificity 94.4% and the accuracy 97.2%. In retrospective clinical evaluation, 60% of the existing fractures were identified in the conventional x-ray images. The remaining fractures were detected by additional procedures like scintigraphy, conventional tomography and CT. CONCLUSION: For the diagnosis of fractures of the body and hook of the hamate HR-CT is the imaging procedure of choice, in which case an axial or sagittal plane should be chosen.

Condensing osteitis of the clavicle in a man.

Condensing osteitis of the clavicle is a rare, benign, usually painful condition leading to sclerosis of the medial end of the clavicle. In the English language literature, this has only been reported in women since its original description by Brower et al. in 1974 [1]. We report a clavicular lesion occurring in a man that is clinically, radiographically, and histologically identical to described cases of condensing osteitis.

Bone mineral density and indexes of bone metabolism in spinal cord injury.

We evaluated the pattern of osteoporosis after spinal cord injury, determined the time-frame of the changes, and elucidated the relationship among parathyroid hormone levels, biochemical markers of bone formation, and the pattern of bone mass loss. We included 176 subjects with spinal cord injury and 62 subjects without spinal cord injury as controls in the study. Bone mineral density of the spine and the proximal femur was measured. The participants' age, level of injury, and length of time since injury were compared with the nonspinal cord-injured controls and with each other. Serum levels of calcium, calcitonin, biochemical markers of bone formation, and parathyroid hormone were determined. Our results revealed that bone mineral density of the proximal femur declined and reached fracture threshold at one to five years after injury. The decline was detected at 12 months after injury in all age groups. Spinal bone mineral density neither declined significantly nor reached fracture threshold. Parathyroid hormone levels declined before the end of the first year postinjury and increased at one to nine years postinjury in the 20- to 39-year age group. The increase correlated with the initial decline of bone mineral density of the proximal femur. Our studies in spinal cord-injured subjects revealed a pattern of osteoporosis similar to age and parathyroid dysfunction-related osteoporosis. No other correlation was detected between indexes of bone metabolism and bone mineral density measurements.

Gamekeeper thumb: comparison of MR arthrography with conventional arthrography and MR imaging in cadavers.

PURPOSE: To compare magnetic resonance (MR) arthrography with conventional arthrography and standard MR imaging in the evaluation of gamekeeper thumb. MATERIALS AND METHODS: Eighteen cadaveric thumbs with (n = 12) or without (n = 6) experimental abduction stress were examined with conventional arthrography, standard MR imaging, and MR arthrography. Standard MR imaging and MR arthrography were performed with 0.2-T (low-field-strength) extremity-only and 1.5-T (high-field-strength) magnets. Results of blinded imaging analyses were correlated with pathologic findings. Paired MR images and MR arthrograms were rated with a three-point scale. RESULTS: Fourteen ulnar collateral ligaments were torn, including eight nondisplaced (57%) and six displaced (43%) tears. For the presence of tear, diagnostic accuracy of conventional arthrography, low-field-strength MR imaging, high-field-strength MR imaging, low-field-strength MR arthrography, and high-field-strength MR arthrography was 83%, 89%, 90%, 94%, and 100%, respectively. With regard to displacement of the torn ligament, diagnostic accuracy was 61%, 89%, 90%, 94%, and 100%, respectively. MR arthrograms were rated superior to standard MR images in 72% and 90% of specimens with low-field-strength and high-field-strength magnets, respectively. CONCLUSION: Of the tested methods, MR arthrography proved to be the most sensitive to the diagnosis of a torn ulnar collateral ligament of the first metacarpophalangeal joint and of displacement of the torn ligament.

The Bennett lesion of the shoulder.

In this article we review the imaging features and significance of the Bennett lesion of the shoulder. Standard radiographic, computed arthrotomographic, and MR findings in three baseball pitchers diagnosed with Bennett lesions of the shoulder are discussed. A crescent-shaped region of mineralization at the posteroinferior aspect of the glenoid rim, consistent with a Bennett lesion, arises at the insertion of the posterior joint capsule. The diagnosis of this lesion, typically in baseball pitchers, should raise suspicion for associated labral and rotator cuff abnormalities.

Update on imaging of orthopedic infections.

Although the diagnosis of infection is only a small part of the orthopedist's job description, it is a important part. This article discusses the fundamentals of orthopedic infections and highlights the refinements on this topic from a radiologic perspective. In addition to reviewing the imaging appearance of musculoskeletal infections in bone and the surrounding soft tissues, we focus on the advantages and disadvantages of five imaging methods: radiography, sonography, CT, scintigraphy, and MR imaging. Finally, we review three specific situations that have garnered substantial attention in recent medical literature: chronic recurrent multifocal osteomyelitis, musculoskeletal infections in AIDS patients, and pedal infections in diabetic patients.

Orthopedic aspects of metabolic bone disease.

Although metabolic bone disorders are common, they may be difficult to distinguish on the basis of clinical and radiologic findings. Understanding their diverse manifestations on imaging studies may allow early diagnosis. This article discusses osteoporosis, osteomalacia, rickets, hyperparathyroidism, hypothyroidism, hyperthyroidism, renal osteodystrophy, and Paget disease, with emphasis on radiologic differential diagnosis.

Scoliosis in elderly and age-related bone loss: a population-based study.

Osteoporosis, a common metabolic condition resulting in reduced bone mass, causes significant morbidity in affected individuals by predisposing them to osteoporotic fractures. To determine the relationship of scoliosis and osteoporosis, dual-energy X-ray absorptiometry (DXA) scans of 493 men and 762 women were analyzed according to their scoliotic status. No association was observed in the few scoliotic men without osteoarthritis of the spine compared to nonscoliotic men. Without osteoarthritis, scoliotic women had significantly decreased bone mass of the total hip and the femoral neck (p < 0.05) compared to nonscoliotic women, whereas in spine, bone mass was also decreased compared to nonscoliotic women, but not statistically significant. This suggests that scoliosis associates with bone loss, and affected women may benefit from early institution of therapeutic measures.

Osteopenia in Rett syndrome.

Bone density analysis, dietary intake, and anthropometrics were compared in 20 subjects with Rett syndrome (RS), 25 normal control subjects, and 11 girls with cerebral palsy. Bone mineral density, bone mineral content, and spine (bone) mineral density were significantly reduced in the RS group. When weight and age were kept constant, the bone density was still reduced in the patients with RS. Subjects with RS are at risk for osteoporosis.