Miho Yamada

RELATION OF EARLY MENARCHE TO HIGH BONE MINERAL DENSITY

The study of background factors in individuals with high bone mineral density (BMD) may provide useful information in the prevention of osteoporosis. We investigated the relationship of reproductive factors to BMD. In 519 female volunteers (327 postmenopausal and 192 premenopausal women) ranging in age from 21 to 74 (mean 52.3 ±11.8) years, spinal BMD values were obtained using both quantitative computed tomography and dual x-ray absorptiometry. The z score was calculated from the mean BMD in each 5-year age group, and high BMD and low BMD was defined as BMD with z score >+1.5 and <-1.5, respectively. Normal BMD was defined as BMD within the range-1.0 <z score <+1.0. Long reproductive period, early menarche, and late menopause were associated with high BMD. Among these, the reproductive period showed the strongest association with BMD. In postmenopausal women, early menopause had a significant relationship with low BMD, and early menarche also had some relation to high BMD. In premenopausal women, there was a significant relationship between early menarche and high BMD. The age at menarche may have a strong association with peak bone mass, as suggested by the positive correlation of early menarche with high BMD observed in this study. It is considered important to prevent risk factors that disturb the beginning of menstruation in adolescent girls.

Relationship of Spinal Fracture to Bone Density, Textural, and Anthropometric Parameters

To investigate risk factors for spinal fracture, we studied the relationship between the prevalence of asymptomatic spinal fracture and various morphological measures including spinal bone mineral density (BMD) in women. A total of 122 women ranging in age from 55 to 79 years were studied. The group consisted of 46 women aged 55–59 years (18 with fracture), 51 women aged 60–69 years (26 with fracture), and 26 women aged 70–79 years (14 with fracture). BMD of cortical and trabecular bone from L1 to L3 was measured using quantitative computed tomography (QCT). Run-length analysis was applied to evaluate the spinal trabecular textural features using CT images; the texture indices which represent the mean width of trabeculae (the T-texture) and that of intertrabecular spaces (the I-texture) were obtained. Anthropometric factors including body weight and height, psoas muscle area, and vertebral bone volume were measured using CT images. Among the various factors, trabecular BMD in women aged 55–69 years showed the highest odds ratio for the presence of fracture per standard deviation (SD) decrease in bone density. However, in women aged 70–79 years, the highest odds ratio was observed for trabecular texture index but not for trabecular BMD. The I-texture in women aged 55–59 years, the muscle area in women aged 60–69 years, and cortical BMD and muscle area in women aged 70–79 years were also considered significantly related to the risk of fracture.

Discrimination of spinal fracture with various bone mineral measurements

For several different bone mineral measurements and various skeletal sites, we compared capability to discriminate between women in various age decades with and without spinal fracture, and attempted to identify the most effective cutoff level in discrimination of spinal fracture. The subjects were 88 women aged 50–59 years (including 32 with fracture), 95 women aged 60–69 years (including 54 with fracture), and 34 women aged 70–79 years (including 18 with fracture). Spinal trabecular and cortical bone mineral density (BMD) were measured using quantitative computed tomography (CT), and spinal, radial (ultra-distal, 10% distal and 33% distal), and calcaneal BMD were measured by dual X-ray absorptiometry. These BMD values were obtained in each subject on the same day. Three statistical techniques—Student’s t-test, the logistic regression analysis, and the receiver operating characteristics (ROC) analysis—were applied and accuracy was calculated using the various cutoff values. The capability to discriminate between women with and those without fracture using these BMD values was different among the three age groups. In women aged 50–59 and 60–69 years, all measurements showed good capabilities for discriminating women with fracture. In women aged 70–79 years, these measurements showed lower capability than in those aged 50–59 and 60–69 years, but among them, the calcaneal and ultradistal radial BMD showed relatively good capability. The 10% and 33% distal radial BMD values were not useful in the detection of the high risk women with fracture. The cutoff BMD values for discrimination of women with fracture varied according to the sites and methods of measurement. For each specific age group, the most suitable measurement methods and the appropriate skeletal sites should be considered, and the effective cutoff values to discriminate those with fracture may differ according to the measurement methods, the skeletal sites examined, and age.

Bone mineral and other bone components in vertebrae evaluated by QCT and MRI.

To evaluate the usefulness of assessing bone components using magnetic resonance imaging (MRI), the contributions of bone components, including mineral, fat and collagen, to bone mineral density (BMD) and T1 relaxation time (T1) were studied using phantoms. Excised human vertebrae were also evaluated by quantitative computed tomography (QCT) and MRI. T1 was shortened with increasing quantities of fat and collagen. In water, T1 was significantly affected by bone density, while in oil, T1 became slightly longer as bone density increased. The presence of fat and collagen caused under- and overestimations of BMD, respectively. There was good correlation between T1 and BMD in osteoporotic vertebrae and the vertebrae with long T1 showed an increased content of hematopoietic marrow and/or abnormally increased bone mineral. It was concluded that the experimental data showed that MRI can contribute to the assessment of bone quality.

Mandibular condyle bone mineral density measurement by quantitative computed tomography : A gender-related difference in correlation to spinal bone mineral density

We conducted volunteer studies to assess age-related changes of mandibular condyle bone mineral density (BMD) and its correlation to the spinal BMD. Quantitative computed tomography was performed on the condyles and spines (L1-3) of 210 healthy subjects (114 men and 96 women, aged 5-85 years). A separate study was performed on 73 young student subjects (39 men and 34 women, aged 23-25 years). The mandibular condyle BMD showed a decrement rate similar to spinal BMD in men, but in women the decrement rate of the mandibular condyle BMD was lower than that of the L1-3 BMD. On the other hand, correlation coefficients in BMD between the mandibular condyle and spine were similar in women and men. Gender-related differences were found to be dramatic when assessed in the young student group; the mandibular condyle and spinal BMDs were highly correlated in women (r = 0.82, p < 0.0001), but no correlation was found in men (r = 0.22). Taken together, these results suggest that the same regulatory mechanisms exist in the mandibular condyle and spine BMDs. However, aside from the spine BMD, additional undefined factor(s), including mechanical stress from the occlusion, may be involved in maintaining mandibular BMD.

ASSOCIATION BETWEEN ANTHROPOMETRIC MEASURES AND SPINAL BONE MINERAL DENSITY

RATIONALE AND OBJECTIVES.The relationship of vertebral bone mineral density (BMD) to various anthropometric factors, including body weight and height, vertebral volume, and muscle area was examined. The sex- and menopause-related differences in these relationships also were studied. METHODS.Both cortical and trabecular BMD were measured using quantitative computed tomography (QCT). Integral BMD was measured using dual x-ray absorptiometry (DXA) in 74 men and in 96 prcmcnopausal and 155 postmenopausal women. The psoas muscle area was measured using CT images. Vertebral volume was determined using CT images and CT topography. RESULTS.Bone mineral density had the strongest relationship with age in postmenopausal women. Trabecular BMD was correlated with muscle area and vertebral volume in premenopausal women, but not in postmenopausal women. The correlation of trabecular BMD with various anthropometric factors in men was stronger than that in women. Dual x-ray absorptiometry- BMD was found to be more affected by bone volume than was QCT-BMD. CONCLUSIONS.The association of anthropometric factors with BMD differs in men and women, as well as in premenopausal and postmenopausal women.

Oral and maxillofacial radiology teaching file on the World Wide Web

An oral and maxillofacial radiology teaching file on the World Wide Web was created effective June 15, 1995. The file contains 106 cases (279 images) of 94 diseases in the oral and maxillofacial region.

QUANTITATIVE EVALUATION OF SIALOGRAMS

RATIONALE AND OBJECTIVES The authors developed and evaluated a quantitative analytic method for interpreting clinical sialograms. METHODS Images were obtained by digital subtraction sialography and transformed into binary form. The duct width of the image was calculated and represented as a normalized histogram. The effects of the volume of contrast medium injected and of the inclination angle of the objects on the histogram were examined. RESULTS In model studies, the normalized histogram was affected insignificantly by these factors. Clinical sialograms of 18 patients with normal results, 12 patients with parotitis, and 5 patients with Sjögren syndrome were preliminarily analyzed by the histogram method and four representative parameters of the histogram. Discriminant analysis showed a relatively high correct-predictive rate in the distinction between patients with normal and abnormal results. CONCLUSIONS This method reduces the effect of observer variation in diagnosing sialograms, and improves diagnostic accuracy for assessing the presence of inflammatory diseases of the parotid gland.

Radiographic analysis of isolated osteosclerotic lesions in the mandible: Panoramic survey of 5431 dental patients

Panoramic radiographs taken of 5431 dental patients ranging in age from 2 to 91 years yielded 272 cases with isolated osteosclerotic lesions in the mandible. The incidence was 5%. These lesions were classified into two categories: condensing osteitis and osteosclerosis as described by Stafne. The two categories were compared according to radiographic appearance, age, location, and number of lesions. The significant differences of the radiographic feature found in boundary and internal structure were apparent. In the analysis of osteosclerosis, 23% of the patients showed abnormal oral findings and systemic diseases. These associated lesions occurred more frequently in patients with multiple osteosclerosis. This fact suggested the need for early detection of systemic diseases and other abnormal oral lesions.

An extensive case of cherubism: A long term follow-up case

The present paper describes the radiological features, including CT, of a case of cherubism followed for a relatively long period. The case demonstrated the active phase of the lesion, which progressed from grade 1 to grade 3 during a 6 year period. The radiographic signs, such as increased radiolucency, inflammatory signs and root resorption as well as laboratory data seemed to be important to diagnose the stage of cherubism and to predict the clinical course of the disease.