Value of MRI Ga fistulography combined with DCE-MRI in the diagnosis of high complex anal fistula with small branch fistula and orificium fistulae

Abstract:

Objective：To diagnoze complex high anal fistula by combined use of MRI Ga fistula radiography and dynamic contrast enhanced MRI（DCE-MRI） and to explore its guiding significance for the diagnosis and treatment of high complex anal fistula. Methods：MRI confirmed 264 cases of high complex anal fistula complicated with small internal fistula，and uncleared branch fistula form December 10，2014 to December 10，2016. DCE-MRI check was firstly performed，than DCE-MRI and GA-DTPA 4 mL+ saline 16 mL in the fistula was soon performed through injection. Youden index and AUC test were performed to test the specificity and sensitivity of the results. Results：Fistulography+DCE-MRI clear displayed fistulography of high complex fistula，external fistula，branch fistula，and fistula T1WI；T2WI showed high signal. Abscess was irregular or horseshoe shaped，T1WI，slightly low signal，T2WI，high signal of fat suppression. The control results of surgery showed that fistulography+DCE-MRI obviously increased the diagnostic value for small fistula and small branch fistula. MRI scan for small fistula showed that Youden index was 31.60%，curve area was 0.576；MRI scan for small branch fistula showed that Youden index was -23.70%，and curve area was 0.176. DCE-MRI for small fistula showed that Youden index was 69.40% and curve area was 0.603；DCE-MRI for small branch fistula showed that Youden index was -4.80% and curve area was 0.201. Fistulography+DCE-MRI for small fistula showed that the Youden index was 87.80%，and curve area was 0.798；fistulography+DCE-MRI for small branch fistula showed that Youden index was 79.50% and curve area was 0.898. Conclusion：Fistulography+DCE-MRI have high clinical significance in the diagnosis and treatment of high complex anal fistula.