Three Dimensional Digital Rotational Imaging in the Evaluation of the Fractures

PURPOSE: To evaluate the usefulness and the application of three dimensional digital rotational imaging (3D DRI) by the evaluation of fractures. MATERIALS AND METHODS: Sixteen patients with clinically diagnosed or suspicious fracture were involved in this study. The lesion or suspicious sites of all 16 cases were spines (n=7), pelvis (n=3) and so on (n=6; knee, elbow, ankle, wrist and foot). In all cases, conventional radiography, multiplanar 2D (slice thickness/pitch=3 or 5 mm/1:1)and volume rendering 3D reconstructed single detector helical CT (HiSpeed Advantage, GE Medical Systems, Milwaukee, WIS) scans and 3D DRI (Integris V-5000,Philips Medical Systems, The Netherlands) with multiplanar intersection and gray scaling as postprocessing technique were performed. 3D DRI was evaluated and compared with conventional radiography, multiplanar 2D CT and volume rendering 3D CT. RESULTS: 3D DRI provided more detail and additional information in 14 cases (88%), comparing with 2D and 3D CT scans. Two fractures were revealed only on 3D DRI other than conventional radiography and CT scans and one case was revealed on 2D CT and 3D DRI. In all cases, we could acquired more detail and additional information from 3D DRI than from 3D CT in the acquisition of 3D imaging. 3D DRI didn't change the classification of fracture in 12 of 13 cases (92%),which revealed the fracture on the conventional radiography or CT. CONCLUSION: 3D DRI can diagnose and evaluate the fracture rapidly and easily with anatomical and spatial resolution by acquisition of 3D imaging with postprocessing using DRI.

Imaging of Melorheostosis: Emphasis on MR Imaging Findings

PURPOSE: To evaluate the usefulness of various radiographic imaging modalities in the diagnosis and characterization of melorheostosis. MATERIALS AND METHODS: We retrospectively evaluated the plain film (n=8), computed tomographic (CT) imaging (n=5) and magnetic resonance (MR) imaging (n=5) findings of eight patients with melorheostosis diagnosed by bone biopsy (n=4) and characteristic radiographic findings (n=8). MR images were obtained with a 1.5-T scanner focused on the region of maximal radiographic abnormality. Pulse sequences include T1-weighted SE, T2-weighted fast SE (n=5) and postcontrast imaging (n=4). In order to define subtle enhancement of the lesions, subtraction MR images were obtained in one case. Imaging findings were analyzed with particular emphasis on the distribution of lesions along the sclerotome, differential radiographic findings between diaphyseal and metaepiphyseal lesions of the long bones, as seen on plain radiographs, and the density and signal characteristics of hyperostotic, lesions, as seen on CT and MR images. RESULTS: Characteristic distribution along the sclerotome was identified in five of eight cases mainly along C6 and 7 (n=2) and L3, 4 and 5 (n=3) sclerotomes. In diaphyseal melorherostosis (8/8), a characteristic finding, i.e., a wax flowing down from the candle, was identified on plain radiographs. In all three patients with metaepiphyseal melorheostosis (3/8), multiple round or oval hyperostotic lesions were seen in the epiphysis and metaphysis of the long bones. On CT, the marrow cavity was partly obliterated by hyperostotic lesions in all five patients with endosteal hyperostosis. Among these, central ground glass opacity with a sclerotic rim was seen in three patients. Periosteal hyperostosis was seen in two of five cases, being visualized as irregular excrescences in the periosteal region and surrounding soft tissue. Individual hyperostosis was visualized as hypointense on T1-weighted images and as a hyperintense center with a surrounding hypointense rim on T2-weighted images (5/5). On postcontrast images, central enhancement was noted in all four cases. In one of these, in which the degree of central enhancement was subtle, subtraction images (postcontrast SE- precontrast SE) also revealed a central signal increment. Central enhancement corresponded to the hyperintense center seen on T2-weighted images (4/4) and the ground-glass opacity seen on CT (2/2). CONCLUSION: Radiographic imaging plays a crucial role in the diagnosis of melorheostosis. The future role of gadolinium-enhanced MR imaging in the characterization of the lesion may be important though further evaluation and pathologic correlation is required.

Relationship between Bone Mineral Density of Lumbar Spine and Fatty Replacement of Lumbar Paraspinal Muscles by Quantitative Computed Tomography

PURPOSE: To investigate whether bone mineral density(BMD) occurs in association with fatty replacement oflower paraspinal muscles and whether it relates with the area ratio(Ps/V) of psoas muscle(Ps) divided by adjacentvertebral body(V). MATERIALS AND METHODS: For the evaluation of osteoporosis, 100 females underwent quantitativeCT. At L1,L2 and L3 levels, the fatty replacement of lower paraspinal muscles was numerically graded and therelationship between this and BMD of the vertebral body was evaluated. The correlation between BMD and Ps/V at L2and L3 levels was also evaluated, as was the relationship between the thickness of subcutaneous fat tissue at L1,L2 and L3 levels. RESULTS: BMD showed significant inverse correlations with the grade of the fatty replacement oflower paraspinal muscles at L1(p<.01), L2 level and L3 level(p<.001). In particular, significant differenceswere established between grade 0 and 2 (p<.05) at L1 level, and between grade 0 and 2, and 1 and 2 (p<.05) at L2and L3 levels. There was markedly low correlation (gamma=.33) between BMD and Ps/V at L3 level(p<.001) and lowercorrelation (gamma=.22) at L2 level(p<.05). At L2 and L3 levels, there was no correlation between the thickness ofsubcutanous fat tissue and BMD or Ps/V. CONCLUSION: The present study demonstrates that there was significantinverse correlation between BMD and fatty replacement of lower paraspinal muscles, and low correlation between BMDand Ps/V.