Comparison of MR diffusion weighted imaging bone marrow ratio and radionuclide bone imaging in the diagnosis of spine metastasis

English Keywords:Spinal metastases  Diffusion-weighted imaging  ECT

English Abstract:

  【Abstract】 Objectives: To compare MR diffusion weighted imaging(DWI) in bone marrow and radionuclide bone imaging in the diagnosis of spine metastasis. Methods: Among the 40 cases with spine metastasis, 21 cases were confirmed by bone biopsy, 13 cases by postoperative pathology, and the other 6 cases by MRI, CT(or X-ray), radionuclide bone imaging and follow-up. DWI(b=500s/mm2, and 1.5T MR scanner) were performed in all 40 patients. The regions of interests(ROIs) were measured on the DWI maps, ROI included the most typical lesions avoiding the necrosis zone. Abnormal marrow signal intensity value was measured as SIA, normal bone marrow signal intensity value in adjacent normal vertebral body was measured as SIN. The bone marrow ratio was defined as(SIA-SIN)/SIN for measuring the typical spinal metastatic bone marrow ratio on DWI. The DWI signal change apparent diffusion coefficient(ADC) and the bone marrow contrast ratio was meassured, which was compared with the radionuclide bone imaging at the same time. Results: Among the 40 cases of spine metastasise, 39 cases had positive DWI, which included 15 cervical, 14 thoracic, and 20 lumbar vertebrae. 162 high signal intensity lesions in the vertebral body were found. Among the 31 cases with positive radionuclide bone imaging, 131 lesions were found in the spine. DWI was more sensitive(97.5%) than radionuclide bone imaging(77.5%) in determing spine metastasis by two independent samples t test, P<0.05. The ADC value of lumbar vertebral body lesions was significantly higher[(1.37±0.51)×10-3mm2/s] than that of the adjacent normal vertebral body[(0.534±0.23)×10-3mm2/s]. The high signal lesions of vertebral metastasis(162) and bone marrow ratio change had higher positive rate than radionuclide bone imaging(131), both with significant differences(P<0.05). Conclusions: Compared with radionuclide bone imaging, DWI signal or bone marrow ratio shows higher potent in determining spine metastasis.