[Value of Diffusion-weighted Imaging and Apparent Diffusion Coefficient in the Differential Diagnosis of Posterior...

Objective To investigate the value of diffusion-weighted imaging(DWI)and apparent diffusion coefficient(ADC)in the diagnosis and differential diagnosis of posterior fossa solid hemangioblastoma(PFSH). Methods We retrospectively analyzed the clinical data of 15 PFSH patients and 58 patients with other hypervascular tumors in the posterior fossa(the latter included 23 cases of meningioma,5 cases of medulloblastoma,8 cases of acoustic neuroma,4 cases of hemangiopericytoma,5 cases of lymphoma,9 cases of metastatic tumor,3 cases of astrocytoma,and 1 case of choroid plexus papilloma)confirmed by operation and pathology.All patients underwent axial DWI scans,and the mean ADC value of solid part of the tumors and the adjacent normal cerebellar white matter were measured,and then the normalized ADC was calculated.In addition,t test was used to compare the differences in mean ADC and normalized ADC between these two groups,and receiver operating characteristic(ROC)curve was applied to analyze the diagnostic performance of normalized ADC. Results Of all the 15 PFSH patients,DWI appeared hypointense in 12 patients and isointense in 3 patients;the signals on ADC maps were isointense or hyperintense;the mean ADC value of PFSHs was(1.881±0.445)×10 ^-3mm ²/s and the normalized ADC was 2.70±0.62.In contrast,in 58 patients with other tumors in the posterior fossa,DWI appeared hyperintense in 51 cases,isointense in 3 cases,and hypointense in 4 cases;the mean ADC value was(0.771±0.202)×10 ^-3 mm ²/s,and the normalized ADC was 1.17±0.33.Thus,the ADC value and normalized ADC value were significantly higher in PFSH than in other tumors in the posterior fossa(t=9.419,P<0.001;t=9.184,P<0.001).The cut-off value of the normalized ADC for the diagnosis of solid hemangioblastoma was 1.89,with the sensitivity and specificity being 100%and 96.6%respectively,and the area under the ROC curve was 0.989. Conclusion ADC and normalized ADC are valuable in the differential diagnosis of PFSH from other tumors with abundant blood supply.