Neurologic pathologies of the vertebral spine

At some institutions, musculoskeletal and general radiologists rather than neuroradiologists are responsible for reading magnetic resonance imaging (MRI) of the spine. However, neurological findings, especially intrathecal ones, can be challenging. Intrathecal neurological findings in the spine can be classified by location (epidural, intradural extramedullary, and intramedullary) or etiology (tumor, infection, inflammatory, congenital). In this paper, we provide a succinct review of the intrathecal neurological findings that can be seen on MRI of the spine, primarily by location and secondarily by etiology, in order that this may serve as a helpful guide for musculoskeletal and general radiologists when encountering intrathecal neurological pathologies.

MRI Findings of Arachnoiditis, Revisited. Is Classification Possible?

BACKGROUND

Prior imaging studies characterizing lumbar arachnoiditis have been based on small sample numbers and have reported inconsistent results.

PURPOSE

To review the different imaging patterns of lumbosacral arachnoiditis, their significance, and clinical implications.

STUDY TYPE

Retrospective.

POPULATION

A total of 96 patients (43 women; average age 61.3 years) with imaging findings of arachnoiditis (postsurgical: N = 49; degenerative: N = 29; vertebral fracture: N = 6; epidural and subdural hemorrhage: N = 3, infectious: N= 1; other: N = 8) from January 2009 to April 2018.

FIELD STRENGTH/SEQUENCE

Sagittal and axial T2-weighted Turbo Spin Echo at 1.5 T and 3 T.

ASSESSMENT

Chart review was performed to assess the cause of arachnoiditis, and imaging was reviewed by two musculoskeletal and three neurology radiologists, blinded to the clinical data and to each other's imaging interpretation. Previous classification included a three-group system based on the appearance of the nerve roots on T2-weighted images. A fourth group was added in our review as "nonspecified" and was proposed for indeterminate imaging findings that did not fall into the classical groups. The presence/absence of synechiae/fibrous bands that distort the nerve roots and of spinal canal stenosis was also assessed.

STATISTICAL TESTS

The kappa score was used to assess agreement between readers for both classification type and presence/absence of synechiae.

RESULTS

Postsurgical (51%) and degenerative changes (30%) were the most common etiologies. About 7%-55% of arachnoiditis were classified as group 4. There was very poor classification agreement between readers (kappa score 0.051). There was also poor interreader agreement for determining the presence of synechiae (kappa 0.18) with, however, strong interreader agreement for the presence of synechia obtained between the most experienced readers (kappa 0.89).

DATA CONCLUSION

This study demonstrated the lack of consensus and clarity in the classification system of lumbar arachnoiditis. The presence of synechia has high interreader agreement only among most experienced readers and promises to be a useful tool in assessing arachnoiditis.

EVIDENCE LEVEL

3 TECHNICAL EFFICACY: Stage 2.

MR Perfusion and MR Spectroscopy of Brain Neoplasms

Advances in imaging techniques, such as MR perfusion and spectroscopy, are increasingly indispensable in the management and treatment plans of brain neoplasms: from diagnosing, molecular/genetic typing and grading neoplasms, augmenting biopsy results and improving accuracy, to ultimately directing and monitoring treatment and response. New developments in treatment methods have resulted in new diagnostic challenges for conventional MR imaging, such as pseudoprogression, where MR perfusion has the widest current application. MR spectroscopy is showing increasing promise in noninvasively determining genetic subtypes and, potentially, susceptibility to molecular targeted therapies.

Thyroid Cancer Bone Metastasis: Survival and Genomic Characteristics of a Large Tertiary Care Cohort

Bone metastasis (BM) in differentiated thyroid cancer (DTC) is the second most common site of metastasis after lung. Bone metastases are associated with worse prognosis in DTC. In this study, we examined risk factors for overall survival in patients with BM and for the first time explore the pattern of genomic alterations in DTC BM.

PATIENTS AND METHODS

A Health Insurance Portability and Accountability Act (HIPAA) compliant, institutional review board-approved retrospective evaluation of the medical record was performed for all patients treated at a single institution for thyroid cancer over a 16-year period. Seventy-four patients met inclusion criteria. Multiple prognostic factors including age, sex, genes, radioactive iodine, and radiation or kinase inhibitor therapies were analyzed. Univariate and multivariate analyses were performed.

RESULTS

Treatment with external beam radiation was found to significantly increase survival (P = 0.03). The 5-year survival rate was 59% and median survival was 92 months. Patients who developed bone metastasis earlier tend to live longer (P = 0.06). The presence of TERT and BRAF mutations did not significantly worsen the prognosis (P = 0.10).

CONCLUSION

Patients with DTC can benefit from early treatment with external beam radiation therapy, especially those who develop bone metastasis within 3 years of primary TC diagnosis. Kinase inhibitor treatment tended to prolong survival but not in a statistically significant manner. Sex, age, and TERT or BRAF genetic mutations did not significantly affect the prognosis.

11C-Choline Pharmacokinetics in Recurrent Prostate Cancer

The aim of this study was to investigate the value of pharmacokinetic modeling for quantifying 11C-choline uptake in patients with recurrent prostate cancer. Methods: In total, 194 patients with clinically suspected recurrence of prostate cancer underwent 11C-choline dynamic PET over the pelvic region (0-8 min), followed by a 6-min static acquisition at about 25 min after injection. Regions of interest were drawn over sites of disease identified by a radiologist with experience in nuclear medicine. 11C-choline uptake and pharmacokinetics were evaluated by SUV, graphical analysis (Patlak plot; KiP), and 1- and 2-compartment pharmacokinetic models (K1, K1/k2, k3, k4, and the macro parameter KiC). Twenty-four local recurrences, 65 metastatic lymph nodes, 19 osseous metastases, and 60 inflammatory lymph nodes were included in the analysis, which was subsequently repeated for regions of interest placed over the gluteus maximus muscle and adipose tissue as a control. Results: SUVmean and KiP were 3.60 ± 2.16 and 0.28 ± 0.22 min-1 in lesions, compared with 2.11 ± 1.33 and 0.15 ± 0.10 min-1 in muscle and 0.26 ± 0.07 and 0.02 ± 0.01 min-1 in adipose tissue. According to the Akaike information criterion, the 2-compartment irreversible model was most appropriate in 85% of lesions and resulted in a K1 of 0.79 ± 0.98 min-1 (range, 0.11-7.17 min-1), a K1/k2 of 2.92 ± 3.52 (range, 0.31-20.00), a k3 of 0.36 ± 0.30 min-1 (range, 0.00-1.00 min-1) and a KiC of 0.28 ± 0.22 min-1 (range, 0.00-1.33 min-1). The Spearman ρ between SUV and KiP, between SUV and KiC, and between KiP and KiC was 0.94, 0.91, and 0.97, respectively, and that between SUV and K1, between SUV and K1/k2, and between SUV and k3 was 0.70, 0.44, and 0.33, respectively. Malignant lymph nodes exhibited a higher SUV, KiP, and KiC than benign lymph nodes. Conclusion: Although 11C-choline pharmacokinetic modeling has potential to uncouple the contributions of different processes leading to intracellular entrapment of 11C-choline, the high correlation between SUV and both KiP and KiC supports the use of simpler SUV methods to evaluate changes in 11C-choline uptake and metabolism for treatment monitoring.