INTRODUCTION: In this study, we aimed to evaluate whether intratumoral microhemorrhage detection on susceptibility-weighted imaging (SWI) could help in preoperative differentiation of cerebellopontine angle (CPA) vestibular schwannomas (VSs) from meningiomas.
METHODS: A total of 75 patients (32 males, 43 females; mean age: 45.5±16.7 years; range, 17 to 68 years) consisting of 61 VSs and 14 meningiomas located in the CPA cistern were retrospectively analyzed. All patients underwent contrast-enhanced magnetic resonance imaging (MRI) using the SWI sequence. All images in our study were obtained with a 12-channel phased-array head coil on a 1.5-Tesla clinical scanner. The presence of intratumoral microhemorrhages on SWI sequence was evaluated by demonstrating blooming artifacts as punctate hypointense regions. Both magnitude and phase-contrast images were used to verify microhemorrhages. All patients in our patient cohort underwent surgery and resected tumor specimens were evaluated by pathology.
RESULTS: All VS cases in our cohort exhibited multiple hypointense small foci causing blooming artifact on magnitude and processed SWI images. In the meningioma population, typical MRI signal intensity characteristics, including an intense homogenous contrast enhancement, were observed. In all the meningioma cases, except for one, there was no blooming artifact due to intratumoral hemorrhage within the mass lesions on SWI images. In only one meningioma case, SWI revealed hypointense microhemorrhages within the mass lesion. Following surgical procedures and tumor resections, pathology specimens were evaluated and absence or presence of intratumoral microhemorrhages were detected. These results were significantly correlated with the SWI findings. We obtained 100% sensitivity, 92.8% specificity, and 98.6% accuracy in terms of differentiating VSs from meningiomas located in the CPA cistern by using the SWI sequence.
DISCUSSION AND CONCLUSION: Meningiomas and VSs are the two most common masses of the CPA cistern and, in some cases, it seems to be difficult to reach an accurate diagnosis with conventional MRI sequences. The SWI can be helpful to solve this problem by demonstrating whether intratumoral microhemorrhages are present or not within mass lesions and, thus, can help to assume a probable accurate diagnosis prior to surgery.