Predictive value of magnetic resonance imaging indications of spinal cord swelling for cervical spondylotic myelopathy prognosis.

BACKGROUND: Magnetic resonance imaging (MRI) is the preferred examination approach for patients with suspected cervical spondylotic myelopathy (CSM). OBJECTIVE: To investigate the predictive value of MRI spinal cord swelling on the prognosis of decompression surgery in patients with CSM. METHODS: A retrospective analysis of 115 patients with CSM who underwent decompression surgery was performed. According to whether cervical MRI showed spinal cord swelling, they were divided into a spinal cord swelling group and non-swelling group. The Modified Japanese Orthopaedic Association (MJOA) score, MJOA improvement rate and abnormal spinal cord enhancement rate in the two groups were compared before and after surgery. Multiple linear regression was used to analyse the influencing factors of the MJOA improvement rate. RESULTS: The time from symptom onset to operation (t= 2.400, p= 0.018) and preoperative MJOA score in the spinal cord swelling group were lower than those in the non-swelling group (t= 3.253, p= 0.002). The body mass index (t= 2.895, p= 0.005), anteroposterior diameter of the spinal canal (t= 4.421, p< 0.001), cross-sectional area (t= 3.136, p= 0.002), postoperative improvement rate (t= 4.277, p< 0.001) and proportion of abnormal enhancement of the spinal cord in the swelling group were higher than those in the non-swelling group (χ2= 3.136, p= 0.002). The preoperative MJOA score in the swelling group was lower than that in the non-swelling group (t= 2.583, p= 0.013). A multivariate linear regression model revealed that age and spinal cord swelling were independent predictors of MJOA score improvement, explaining 33.2% of the total variation. CONCLUSION: Patients with CSM with spinal cord swelling have less time from symptoms to surgery, and the degree of preoperative neurological deterioration is more obvious. Spinal cord swelling is an independent predictor of surgical prognosis in patients with CSM.

Signal characteristics of normal adult bone marrow in whole-body diffusion-weighted imaging.

BACKGROUND: Knowledge of the signal characteristics of normal adult bone marrow in whole-body diffusion-weighted (DW) images (WB-DWI) is essential for correctly interpreting DW images in clinical practice; however, these factors have not yet been clearly determined. PURPOSE: To evaluate the signal characteristics of normal adult bone marrow in WB-DWI, to correlate these characteristics with age and gender, and to determine the causes of these phenomena. MATERIAL AND METHODS: Ninety-eight healthy volunteers underwent WB-DWI (b = 0 and 800 s/mm(2)). Two radiologists visually evaluated the signal characteristics of bone marrow in DW images separately. One radiologist measured the apparent diffusion coefficient (ADC) of the thoracic and lumbar vertebrae, bilateral femur (including head, neck, and proximal and distal femoral shaft), bilateral humeral head, ilium, and scapula. The signal characteristics of normal bone marrow were analyzed. RESULTS: The visual evaluation results of DW images indicated that hyperintensity of bone marrow was more frequently seen in women aged 21-50 years (68.4%) than in men aged 21-50 years (3.3%) (P < 0.001), men aged 51-81 years (5.9%) (P < 0.001), and women aged 51-81 years (15.4%) (P = 0.001). However, no statistically significant difference was found between men and women aged 51-81 years (P = 0.565). The ADC of bone marrow was significantly higher in women than in men aged 21-50 years. Bone marrow ADC showed significant negative correlation with age in women but not in men. CONCLUSION: The signal intensity of bone marrow varies with age and gender in DW images. ADC and the T2 shine-through effect contributed to the bone marrow signal intensity in DW images, and the latter effect may predominate.

Differentiating benign from malignant bone tumors using fluid-fluid level features on magnetic resonance imaging.

OBJECTIVE: To analyze different fluid-fluid level features between benign and malignant bone tumors on magnetic resonance imaging (MRI). MATERIALS AND METHODS: This study was approved by the hospital ethics committee. We retrospectively analyzed 47 patients diagnosed with benign (n = 29) or malignant (n = 18) bone tumors demonstrated by biopsy/surgical resection and who showed the intratumoral fluid-fluid level on pre-surgical MRI. The maximum length of the largest fluid-fluid level and the ratio of the maximum length of the largest fluid-fluid level to the maximum length of a bone tumor in the sagittal plane were investigated for use in distinguishing benign from malignant tumors using the Mann-Whitney U-test and a receiver operating characteristic (ROC) analysis. Fluid-fluid level was categorized by quantity (multiple vs. single fluid-fluid level) and by T1-weighted image signal pattern (high/low, low/high, and undifferentiated), and the findings were compared between the benign and malignant groups using the χ(2) test. RESULTS: The ratio of the maximum length of the largest fluid-fluid level to the maximum length of bone tumors in the sagittal plane that allowed statistically significant differentiation between benign and malignant bone tumors had an area under the ROC curve of 0.758 (95% confidence interval, 0.616-0.899). A cutoff value of 41.5% (higher value suggests a benign tumor) had sensitivity of 73% and specificity of 83%. CONCLUSION: The ratio of the maximum length of the largest fluid-fluid level to the maximum length of a bone tumor in the sagittal plane may be useful to differentiate benign from malignant bone tumors.