Clinical Reasoning: A 57-Year-Old Man With Stepwise Progressive Paraparesis, Sensory Loss, Urinary Retention, and Constipation

Utility of T2-weighted MRI and contrast-enhanced MRA in locating the fistula level of spinal arteriovenous fistula

OBJECTIVE

To investigate the value of routine T2-weighted magnetic resonance imaging (MRI) and contrast-enhanced magnetic resonance angiography (CE-MRA) sequences in locating the fistula level of spinal arteriovenous fistula (SAVF).

METHODS

Retrospectively analyzed the radiological findings of patients with SAVF diagnosed by surgery from May 2018 to September 2024. All patients completed spinal CE-MRA and routine T2-weighted MRI. The imaging manifestations of SAVF lesions on CE-MRA and MRI were summarized and analyzed.

RESULTS

We enrolled 40 cases with SAVF (average age 58.1 years old, 85.0% male). The majority of fistulas were located in the thoracic (60.0%), followed by the lumbar (27.5%), and cervical (12.5%). Based on CE-MRA images, the fistula of 33 cases (82.5%) with SAVF can be accurately located, the perimedullary varicose vessels of 34 cases (89.47%) can be shown, and the feeding arteries of 27 cases (71.05%) can be identified. Based on T2-weighted MRI, the perimedullary flow voids and T2 hyperintensity were seen in 36 (90.0%) of SAVF cases, the fistula level in 88.9% (32/36) of cases was located at one end of the flow voids within 1 vertebral level, and the flow voids of 72.2% (26/36) cases near the fistula to be more tension. There is no significant difference in the accuracy of routine T2-weighted MRI in locating the fistula level compared to CE-MRA and digital subtraction angiography (DSA).

CONCLUSION

Both routine T2-weighted MRI and CE-MRA sequences are valuable in the detection of SAVF fistula, we can locate the fistula level by the clues of the perimedullary varicose vessels.

Diagnosis of spinal dural arteriovenous fistula: a multimodal MRI assessment strategy

AIM

To identify more specific screening indicators at magnetic resonance imaging (MRI) for the diagnosis of spinal dural arteriovenous fistulas (SDAVFs) and to determine an efficient diagnostic strategy.

MATERIALS AND METHODS

This retrospective study analysed clinical and imaging data of patients diagnosed with SDAVF and alternative myelopathy who underwent conventional MRI examinations. Additionally, three-dimensional (3D) T2-weighted sampling perfection with application-optimised contrasts using different flip-angle evolutions (3D-T2-SPACE) and contrast-enhanced magnetic resonance angiography (CE-MRA) data from patients with SDAVF were compared with digital subtraction angiography (DSA) data.

RESULTS

The age of onset, perimedullary flow voids (PFV), distribution of lesions, syringomyelia, degree of spinal oedema, and cauda equina disorder (CED) were factors that showed statistically significance in the identification of SDAVF with alternative myelopathy. After controlling for age, gender, PFV, degree of spinal cord swelling, and syringomyelia, the multivariable ordinal logistic regression model showed that the CED sign (OR = 32.46; 95% confidence interval [CI]: 2.47-427.15; p=0.008) was an independent predictor for SDAVF. The diagnostic model constructed using the PFV and CED signs had better diagnostic performance, with an area under the curve of 0.957 (p<0.001), maximum Youden index of 0.844, sensitivity of 92.9%, and specificity of 91.5%. Both 3D-T2-SPACE (77.8%) and CE-MRA (83.3%) sequences had good localisation values for SDAVF. Combining the two imaging examinations had better diagnostic accuracy than that of DSA.

CONCLUSION

CED and PFV on conventional MRI were specific indicators for the diagnosis of SDAVF. To compensate for the lack of fistula localisation on conventional MRI, 3D-T2-SPACE and CE-MRA can be used. Together they complement each other and have good diagnostic potential.

The value of 3D T2-weighted SPACE sequence in the differential diagnosis of spinal arteriovenous fistula and acute transverse myelitis

OBJECTIVE

Spinal arteriovenous fistulas (SAVF) was often neglected and misdiagnosed as acute transverse myelitis (ATM) due to its insidious onset and non-specific clinical symptoms. This study aims to investigate the differential diagnostic value of high-resolution T2-weighted volumetric sequence (3D sampling perfection with application-optimized contrasts using different flip-angle evolutions [SPACE]) in patients with SAVF and ATM.

METHODS

Retrospectively analyzed the clinical and radiological findings of 32 SDAVF patients and 32 ATM patients treated at our institutions from May 2018 to January 2023. They all underwent conventional spinal MRI and T2-SPACE examination, compared their performance in identifying lesions, to estimate the value of T2 SPACE sequence in the diagnosis of SAVF and ATM patients.

RESULTS

The clue of cauda equina area change (CEAC) in conventional MRI and T2-SPACE sequences is specific for the diagnosis of SAVF. The diagnostic model composed of perimedullary flow voids (PFV) and CEAC has good diagnostic performance (AUCMRI = 0.95; AUCSPACE = 0.935). Compared with conventional MRI, the T2-SPACE sequence has a higher detection rate, sensitivity, and negative predictive value for PFV and CEAC in SAVF patients, but lower specificity and positive predictive value. In T2-SPACE images, there are significant differences in the distribution range, quadrant, and maximum diameter of PFV vessels between SAVF and ATM patients. Moreover, T2-SPACE sequence can determine the site of fistula in most SAVF patients preferably, and the inter-rater agreement was good in the assessment of the fistula.

CONCLUSION

The CEAC is a new and useful clue for the diagnosis of thoracolumbar SAVF. And T2-SPACE sequence can more intuitively observe the lesions of SAVF, has good differential diagnostic value for SAVF and ATM patients.

Clinical and prognostic features of venous hypertensive myelopathy from craniocervical arteriovenous fistulas: a retrospective cohort study

OBJECTIVE

Current knowledge about venous hypertensive myelopathy (VHM) is incomplete. This study was performed with the aim of clarifying the clinical features and outcomes of craniocervical VHM.

METHODS

This retrospective, single-center cohort study included 65 patients with craniocervical junction arteriovenous fistulas resulting in VHM treated in Xuanwu Hospital from January 1, 2002, to December 30, 2020. All patients underwent microsurgery or endovascular treatment. The primary outcome was neurological function assessment using the Japanese Orthopaedic Association (JOA) scale, modified Aminoff-Logue Scale (mALS), and Venous Hypertensive Myelopathy Scale (VHMS). The secondary outcomes were recurrences and postoperative adverse events. Pearson linear regression and receiver operating characteristic curves were used to evaluate the relationships among the three scales. Kaplan-Meier and multivariate logistic regression analyses were performed to predict outcomes.

RESULTS

The mean patient age was 57.4 ± 11.4 years, and 88% of patients were male. The 1-year follow-up rate was 83.1%, and the 5-year follow-up rate was 50.8%. The VHMS was correlated with the JOA (R2 = 0.6722) and mALS (R2 = 0.7399) and increased the assessment accuracy by approximately 20% when compared with the other two scales. Overall, 25.9% of patients experienced delayed neurological decline beyond the 1-year follow-up. Further logistic regression suggested that age > 65 years was an independent predictor (OR 7.831, 95% CI 1.090-56.266; p = 0.041). Embolic recanalization and new bilateral symmetry feeders were the major reasons for recurrence. Recurrence increased the risk of adverse events after the second surgery (OR 20.455, 95% CI 1.170-357.320; p = 0.039).

CONCLUSIONS

CCJ AVFs resulting in VHM are a rare but deadly complication, and providers should be cautious of age-related delayed neurological decline and strive for a one-time anatomical cure.