Role of susceptibility weighted imaging in characterization of intra-cranial lesions

Abstract

Background: Intrinsic differences between magnetic susceptibility of tissues can be used to generate a unique type of contrast in Magnetic Resonance Imaging (MRI), particularly to characterize tissues and improve the sensitivity for certain lesions, most notably hemorrhagic foci or calcification. Methods: A blinded retrospective review of all brain imaging studies done at our centre between March 2014 and February 2016. One of them reviewed the MR images with exclusion of SWI, while the other radiologist reviewed the entire set of images including SWI. Their findings were then compared to study the efficacy of SWI in better detection and characterization of lesions. Results: The study included 3710 patients with different brain lesions. SWI revealed positive lesions in at least 619 of these patients which were not picked up by the radiologist interpreting the conventional MRI protocol without SWI sequence. 21 patients with traumatic brain injury, 32 patients with cerebral microbleeds, 78 patients with brain tumors, 27 patients with venous malformations, 128 patients with intra-cranial calcifications, 277 patients with infarcts and 56 patients with extra-axial hemorrhage. Out of the 619 lesions, SWI played a significant role in lesion characterization in at least 198 patients which is about 5.33% of our total cohort of 3710 patients. Conclusion: SWI images are fast sequences requiring no more than a total scan time of about 3 minutes. Inclusion of this sequence as a part of brain pathology can play an important role in diagnosing different brain lesions without missing hemorrhagic lesions thus avoiding inappropriate therapeutic regimens with catastrophic results.

Study of Significance of Phase Mask Image in Acute Stroke Patients

“…Among these infarcts, the hemorrhagic transformation is observed in 15 patients on SWI as well as conventional sequences. Whereas study by Sahdev R et al 11 revealed that 277 patients revealed positive findings on SWI. Among these, hemorrhagic transformation identified in 189 patients on SWI and conventional sequences.…”

“…In the remaining two patients, low signal intensity was perceived on the conventional sequences. Whereas study by Sahdev R et al 11 revealed, 128 patients were diagnosed with calcified granulomata, and out of these, SWI was useful in detecting 46 lesions that were indiscernible on other sequences. Zhu WZ et al 19 described that calcification and hemorrhage manifested the low signal on SWI.…”

“…In our study, we identified 60 patients, where SWI revealed the multiple foci of 'blooming' suggestive of microbleeds, out of them 46 patients had a positive history of hypertension. Whereas, a study by Sahdev R et al 11 encountered 32 patients where SWI revealed multiple foci of 'blooming' suggestive of cerebral microbleeds. Regarding the traumatic brain injury (TBI), the detection of huge intracranial hemorrhage has always been important for management.…”