MRI and Anatomical Determinants Affecting Neuroforaminal Stenosis Evaluation: A Descriptive Observational Study.

Purpose: Neuroforaminal stenosis (NFS), a narrowing of the intervertebral foramen, is a cause of disability in the aging population. Formal magnetic resonance imaging (MRI) classification of NSF has been developed recently and contradictory findings have been reported. This study aims to assess whether in-plane, anatomically conformed two-dimensional (2D) views of the neuroforamen characterize NFS more accurately than traditional axial, coronal, and sagittal views in healthy individuals with and without simulated scoliosis. Patients and methods: This observational study was approved by the designated institutional review board at our academic tertiary care center. Four volunteers underwent lumbar spine MRI twice, once in the supine position and once with intentionally introduced hip tilt. The latter resulted in lumbar curvature mimicking positioning errors approximating degenerative lumbar scoliosis. Anatomically oriented cuts such as axial with endplate correction and coronally obliqued parasagittals, also called coronal obliques, were performed. Standard sagittal and axial views were also performed in both the supine and rotated groups. Results: Coronal oblique and anatomically oriented axial views demonstrated the highest correlation with true neuroforaminal caliber. Deviation from anatomical congruence resulted in false measurements of neuroforaminal size. The hip-tilt studies produced MR that were less favorable to characterization of the caliber of neuroforamina. Coronal sections demonstrated reliability only when performed at the mid-pedicular lines. Standard axial views were reliable only when taken at the upper one-third of the neuroforamen. Coronal oblique views demonstrated superiority when evaluating consecutive neuroforamen on one image compared to non-obliqued parasagittal slices. Conclusion: To minimize error in neuroforaminal analysis, imaging specialists should perform anatomically oriented cuts to conform to individual patient anatomy. When this cannot be performed due to a patient's spine rotation or position, the MRI reader should view oblique, axial, and coronal images simultaneously and dynamically for proper foraminal characterization.

Racial Differences in Iliac Crest Cancellous Bone Composition: Implications for Preoperative Planning in Spinal Fusion Procedures.

STUDY DESIGN: This was a retrospective cohort study. OBJECTIVE: The objective of this study was to determine whether race, specifically American white and American black, correlates with the ratio of cancellous to total bone at the iliac crest. SUMMARY OF BACKGROUND DATA: Studies have demonstrated higher proximal femur bone density in American blacks than American whites. However, whether differences occur at the iliac crest, a common site for autologous graft material in spinal fusion surgery, is not well studied. Understanding such differences could aid orthopedic surgeon decision-making regarding graft options. MATERIALS AND METHODS: A retrospective review was performed on 133 sequential patients ages 18-75 who underwent computed tomography scan of the pelvis, at a single academic medical center from January 1, 2014, to January 1, 2016. The cohort included 46 American white (21 females, 25 males) and 87 American black participants (40 females, 37 males), an average age of 51.8 years. Groups were matched regarding age, sex, body mass index, and Charlson Comorbidity Score. Measurements of cortical and cancellous bone thickness in the right and left iliac crests were performed using bone window protocol on computed tomography scans. Statistical significance was determined using a 2-tailed t test. RESULTS: The interobserver interclass correlation coefficient reliability (N=2) for measurements at the right iliac crest is 0.895 (95% confidence interval, 0.852-0.925), and the interclass correlation coefficient for the left iliac crest is 0.912 (95% confidence interval, 0.877-0.938). A statistically significant difference in the mean cancellous bone ratio was found between American black (0.667±0.065) and American white (0.750±0.051) groups (P<0.001). CONCLUSIONS: At the iliac crest, American black patients had a lower mean ratio of cancellous to the total bone as compared with American white patients. This population may benefit from alternative graft options. While iliac crest autograft remains the first option for fusion surgeries, alternative options should be considered to ensure that each patient receives the best-personalized care.

Biochemical magnetic resonance imaging of knee articular cartilage: T1rho and T2 mapping as cartilage degeneration biomarkers.

Osteoarthritis (OA) is a disease whose hallmark is the degeneration of articular cartilage. There is a worsening epidemic of OA in the United States today, with considerable economic costs. In order to develop more effective treatments for OA, noninvasive biomarkers that permit early diagnosis and treatment monitoring are necessary. T1rho and T2 mapping are two magnetic resonance imaging techniques that have shown great promise as noninvasive biomarkers of cartilage degeneration. Each of the two techniques is endowed with advantages and disadvantages: T1rho can discern earlier biochemical changes of OA than T2 mapping, while T2 mapping is more widely available and can be incorporated into existing imaging protocols in a more time-efficient manner than T1rho. Both techniques have been applied in numerous instances to study how cartilage is affected by OA risk factors, such as age and exercise. Additionally, both techniques have been repeatedly applied to the study of posttraumatic OA in patients with torn anterior cruciate ligaments.