Multiplanar evaluation of radiological findings associated with acetabular dysplasia and investigation of its prevalence in an Asian population: a CT-based study.

BACKGROUND: Acetabular dysplasia (AD) is a well-known cause of osteoarthritis (OA) of the hip, with its prevalence previously determined on plain radiography. The prevalence of preexisting AD was reported as 7.3% in a patient-based Asian population. Although computed tomography (CT) could evaluate AD in multiple planes, its prevalence using multiplanar CT images has not been reported. We investigated its prevalence with CT on coronal, axial, and sagittal planes and then determined if adding the axial and sagittal planes enhanced the investigation. METHODS: We retrospectively examined 52 consecutive Japanese individuals (mean age 59.4 years) who had undergone CT for conditions unrelated to hip disorders. The inclusion criteria of CT images were (1) reconstructed axial slice thickness of ≤1 mm and (2) normal pelvic rotations and tilt. Exclusion criteria were (1) age <20 years, (2) neither hip center could be clearly detected, (3) evidence of hip OA. The parameters used to define AD on the coronal plane were the center-edge angle, Sharp angle, acetabular index, acetabular depth ratio, and acetabulum head index. The anterior and posterior acetabular sector angles were used as axial parameters and the vertical-center-anterior margin angle as the sagittal parameter. AD prevalence was calculated using multiplanar images and then compared with the previously reported Asian prevalence using 95% confidence intervals (CI). In this study, we defined "prevalence" as the proportion of subjects who had AD in at least one hip. RESULTS: The mean prevalence of AD on coronal, axial, and sagittal planes was 16.9, 15.4, and 7.7%, respectively. The lowest prevalence found by combining the three planes was 25.0% (95% CI 15.2-38.2%). This prevalence was significantly higher than that in the previously reported Asian population (7.3%). CONCLUSIONS: At the lowest estimate, the prevalence of AD evaluated in three planes was more than twice as high as the previously reported prevalence in Asians when we investigated its prevalence using multiplanar images. The prevalence of AD in the axial and sagittal planes was not negligible. We therefore suggest that it is important to add axial and sagittal planes' data when investigating the prevalence of AD.

Radiographic measurement of cardiac size in 64 ferrets.

As ferrets can suffer from a wide variety of cardiac disorders, indicators for detecting cardiac abnormalities on plain chest radiography are necessary. A total of 64 ferrets without heart disease underwent radiography in the right lateral (RL) and ventrodorsal positions (VD), and the lengths of the RL-sixth dorsal vertebra (6th DV), RL- and VD-long axis (LA) and RL- and VD-short axis (SA), RL- and VD- vertebral heart size, VD-length of the eighth costa (LEC) and VD-thoracic width at the eighth thoracic vertebra (8th TV) were measured to establish standard values of normal cardiac appearance. We evaluated statistical differences between genders and ferrets weighing < 1 kg and > or = 1 kg for a total of 38 items. As a result, significant differences (P<0.05) were observed in all items, including some differences that have been reported previously. In particular, the present study established highly accurate standard values for weight differences. Standard values calculated based on the 6th DV and a relational expression obtained by the regression coefficient of the ratio of VD-SA to VD-8th TV, VD-8th TV=2.887 + (0.769 x VD-SA), were considered useful for evaluating normal cardiac morphology in ferrets.