Histomorphometrical analysis of vertebral lamina with osteofluorosis and its correlation with signal intensity in MRI / 中华骨科杂志

ABSTRACT

Objective To analyze histomorphometrical characteristics of bone and bone marrow tissue in the vertebral lamina of patients with osteofluorosis, and to explore the influencing factors on signal intensity in MRI. Methods Spinal MRI of 109 patients (57 men, 52 women;age range 32-80 years;mean age 52 years) with osteofluorosis from December 2001 to May 2012 was analyzed retrospectively, including 48 patients in cervical segment, 31 in thoracic segment and 30 in lumbar segment. 36 pa?tients (16 men, 20 women;mean age 51 years;age range 34-68 years) had undergone laminectomy and the vertebral lamina speci?mens were collected. The cervical MRI of 48 patients with matching gender and age (26 men, 22 women;mean age 51 years, age range 34-71 years) was selected as control group, who were from areas where fluorosis is not endemic. All patients were divided in?to vertebra low, medium and high signal groups according to T1WI of MRI. The vertebra signal to noise ratio measure and stan?dardization of signal intensity were performed. Osteosclerosis, osteoporosis and normal bone were differentiated under spinal X?ray plain film. Combined with histomorphometric analysis of vertebra lamina in 36 patients, correlation between MRI signal intensity, histomorphometric parameters of the vertebra lamina and influencing factors on signal intensity were studied. Results 77 pa?tients (70.6%, 77/109) had osteosclerosis indicated by appearance of spine under X?ray, 29 (26.6%, 29/109) osteoporosis and 3 (2.8%, 3/109) normal bone. T1WI of MRI showed 25 cases had low signal vertebra, 52 medium signal and 32 high signal. The ver? tebra SNR in patients with osteofluorosis was lower on T1WI, T2WI and short time inversion recovery (STIR) sequences, compared with control group. Those with a low versus high signal on T1WI had 6.04 times the odds of osteosclerosis (OR=6.04, 95%CI 2.44-14.91, P<0.001). Histomorphometry of vertebral lamina in 36 patients with osteofluorosis was performed, revealing that not only the trabecular bone volume had changed, but also did the adipocyte volume and hemopoietic cell volume in the bone marrow tis?sues. Compared with normal reference values, trabecular bone volume was significantly increased (47.7%± 13.3% vs. 14.7%± 4.3%) (P<0.001);adipocyte volume was significantly decreased (12.3%±9.1%vs. 50.5%±8.7%);hematopoietic cell volume was decreased (40.0%±7.0%vs. 42.5%±8.5%) (P=0.038). There were inverse associations between trabecular bone volume and adipo?cyte volume (r=-0.869, P<0.001), and between trabecular bone volume and T1WI (r=-0.851, P<0.001) found by Pearson correla?tion test. In contrast, there were positive associations between T1WI and adipocyte volume (r=0.927, P<0.001). Conclusion The vertebra T1WI signal intensity is decreased in patients with osteofluorosis, resulting from increase of trabecular bone volume and re?duction of adipocyte volume. The vertebra STIR signal intensity is decreased, mainly caused by increase of trabecular bone volume.