2454. Diagnostic Accuracy of MR Venography in May-Thurner Syndrome
Authors * Denotes Presenting Author
  1. Sandeep Hedgire; Massachusetts General Hospital
  2. Ukasha Habib *; Massachusetts General Hospital
  3. Vinit Baliyan; Massachusetts General Hospital
  4. Sarah Mercaldo; Massachusetts General Hospital
To assess the diagnostic accuracy of quantitative and qualitative imaging parameters of pelvic veins for diagnosing May-Thurner syndrome.

Materials and Methods:
This was a retrospective study of consecutive patients who underwent contrast-enhanced MR venography (MRV) of the abdomen and pelvic veins between September and December 2017. Based on imaging and clinical evaluation, patients were divided into cases and controls. Different qualitative attributes of May-Thurner syndrome were collected from the medical records (e.g., clinical signs like lower extremity swelling, DVT, and stroke; ultrasound signs like reflux and loss of phasic flow of Doppler waveform; and interventions like balloon dilatation and stenting. MRV imaging was assessed for quantitative parameters like long and short diameter and cross-sectional area (CSA) of left common iliac vein (CIV) at the narrowest point and was compared with the same attributes at the site of maximum dilatation of left CIV, the IVC, and the right CIV. Imagings were also assessed for qualitative parameters like the presence of collateral veins and flow reversal. The two groups were compared using the Wilcoxon test and Pearson’s chi-squared tests for the diagnostic accuracy of qualitative and quantitative parameters.

There were 26/65(40%) cases and 39/65(60%) controls. Among the qualitative parameters, left lower extremity reflux was not present in any cases but was present in 2/31 (6.5%) of the controls (p = 0.247). The subjects compared to the controls, had a higher rate of collaterals (62% vs 0%, p = <0.01) and DVT (23.1% vs %5.1, p = 0.031). Among quantitative parameters, the long and short axis diameters of left CIV at the site of compression compared to the right CIV were highly sensitive (85% and 81%, respectively). The CSA of left CIV at compression site compared to its CSA at its widest point, and diameter across the long axis of left CIV at compression site compared to that at its widest point, diameters across the long and short axis of left CIV at compression site compared to those of the IVC were highly specific (specificity 76.9%, 100%, 74.4%, 74.4%, respectively)

The diameter and CSA of left CIV at the site of compression has high sensitivity and specificity for diagnosing May-Thurner syndrome.