Comparative Analysis of Diagnostic Sensitivity of Magnetic Resonance Susceptibility Sequence with Non Enhanced Computed Tomography and Magnetic Resonance Gradient Sequence in Early Haemorrhagic Transformation of Cerebral Infarction- A Cohort Study

Abstract

Introduction: Susceptibility Weighted Imaging (SWI) is a Magnetic Resonance Imaging (MRI) sequence aiming to enhance contrast in MR imaging. SWI is considered to be sensitive in detecting even minute amount of haemorrhage, putting in consideration that early detection of haemorrhage inside acute infarction restricts the use of thrombolytic drugs and minimise the development of large haematoma that need to be evacuated surgically thus, improving the prognosis of the patient. Aim: To evaluate and compare the diagnostic sensitivity of MR SWI with Non Enhanced Computed Tomography (NECT) and Magnetic Resonance Gradient Recalled Echo (MR GRE) sequence in detecting the early Haemorrhagic Transformation (HT) of cerebral infarction. Materials and Methods: This was a cohort study conducted from July 2018 to October 2019 on 45 patients referred to the Radiology Department of the institute with imaging findings suggestive of stroke. Apart from the NECT brain conducted on 128 slice machine and routine stroke protocol, MR SWI was also performed. MRI study was performed on 1.5 Tesla MRI scanner with a eight channel Navigator radiofrequency coil. A follow-up CT was done after 48 hours. The images obtained were subjected to radiological analysis and interpretation. Statistical Package for Social Sciences (SPSS) version 22, descriptive analysis was carried out by calculating mean±standard deviation, frequency and proportion. The collected data was compared with each other, using Chi-square test and Fisher's-exact test, correlated using Spearman Correlation test. Results: Total 45 patients (mean age: 56 years, 31 males and 14 females) were included in the study. The diagnostic sensitivity of MR SWI in detecting early HT was high 97.5% compared to 45.0% of NECT and 82.5 % of MR GRE. However, the specificity of MR SWI (33.3%) and that of MR GRE (33.33%) were very low as compared to NECT (66.67%), which had a higher specificity in detection of HT. There was a weak positive correlation between surface area of bleed in GRE and surface area of bleed in SWI (Spearman’s RHO correlation 0.324, p-value 0.030). Conclusion: MR SWI had high diagnostic sensitivity in detecting HT earlier than NECT and MR GRE sequence and hence, it could play a crucial role in the treatment of patients. One of the most dreaded complications of cerebral infarctionintracerebral haemorrhage could be prevented and thus, prognosis of the patient improves. Hence, MR SWI sequence should be added to routine stroke protocol, however it cannot replace NECT, since the specificity of NECT is high compared to MR SWI.

Keywords

• contrast
• detection
• enhance
• haemorrhagic infarct
• stroke
• susceptibility weighted imaging