MRI offers high sensitivity and specificity, as well as positive and negative predictive value in detecting infection without the radiation.
Thoracic MRI performs equivalently to thoracic CT when imaging for COVID-19 pneumonia in patients, limiting radiation exposure to these individuals.
In a study published Aug. 15 in Academic Radiology, investigators from Sakarya University in Turkey outlined the similarities in diagnostic performance between the two modalities. Their findings are beneficial, they said, since MRI can be used repeatedly to monitor these patients throughout the course of the disease.
“Although thorax CT is widely used in the imaging of COVID-19 infection, we consider that MRI can be used as an alternative due to its various advantages,” said the team led by Onur Taydas, M.D., assistant professor of radiology. “Especially, MRI is important to assess lung pathology over time as more is learned about COVID and the long-term impact on lung health.”
Despite being more expensive and taking longer to complete scans, the team said, MRI can be useful in supplying additional information to CT during patient follow-up.
Taydas’s team based their evaluation on a retrospective study of 32 patients – 17 women and 15 men – diagnosed with COVID-19 pneumonia in their institution from March 27, 2020, to April 13, 2020, who underwent both CT and MRI within 24 hours of each other. MRI scans were performed on a 1.5T system, and CT images were obtained with either a 64-row or 16-row multi-detector scanner. The team evaluated all images for opacity and unilateral or bilateral involvement.
According to their analysis, 31 patients (96 percent) showed signs of COVID-19 pneumonia on both CT and MRI. Ground-glass opacities were the most common finding, and they were detected in the CT scans of 29 patients (90.6 percent), as well as on their MRI images. CT detected 90 lesions, and MRI identified 85 – results that showed no statistically significant difference, they said. In addition, the team identified consolidation in the CT and MRI scans of 14 patients (43.75 percent), and they identified nodules in 12 CT scans (37.5 percent) and 11 MRI scans (34.4 percent).
Overall, using the CT findings as a reference, point, they calculated MRI’s sensitivity, specificity, positive predictive value, and negative predictive value to be 91.7 percent, 100 percent, 100 percent, and 95.2 percent, respectively.
“The most important result of our study is the nearly complete overlap of CT and MRI findings,” they said. “In this context, MRI was shown to be a useful modality in terms of showing both parenchymal and extraparenchymal (pleural effusion and lymphadenopathy) findings.”