Chest CT has been widely used to diagnose COVID-19 disease, but MRI offers an attractive alternative that doesn't require radiation, according to a study published August 15 in Academic Radiology.
The study results offer clinicians coping with COVID-19 a useful alternative when it comes to diagnostic follow-up, wrote a team led by Dr. Omer Faruk Ates of Sakarya University in Turkey.
"Since there is no radiation risk, MRI allows multiple examinations to be performed on the same patients, and it can provide additional information to CT during patient follow-up," the group noted.
Real-time reverse transcription polymerase chain reaction (RT-PCR) testing is considered the gold standard for diagnosing COVID-19, but imaging is also important for assessing the extent of disease, the group noted. And since CT confers radiation, MRI offers a good alternative, especially since new techniques (such as the T2-weighted spin-echo propeller sequence) improve the modality's performance in the lung.
The study included 32 patients with COVID-19 who underwent thoracic CT and MRI for follow-up within 24 hours of the original CT scan. The group tracked the number of lung lobes affected, the number of lobes that manifested ground-glass opacities and consolidation, the number of nodules, distribution of lesions, and presence of pleural effusion.
Of the patients, 96.9% had signs of pneumonia on CT, with the most common finding being ground-glass opacities (90.6%), followed by consolidation (43.8%). These two CT findings were also observed on MRI, the group noted.
| Performance of CT and MRI in detecting COVID-19 in the lungs | ||
| Measure | CT | MRI |
| Lung involvement | 96.9% | 96.9% |
| Location of lesion | ||
| Peripheral | 65.6% | 65.6% |
| Central | 3.1% | 3.1% |
| Diffuse | 28.1% | 28.1% |
| Image quality | ||
| Moderate | 18.8% | 18.8% |
| Good | 25% | 43.8% |
| Excellent | 56.3% | 34.4% |
Ates and colleagues found that MRI's sensitivity for detecting lung nodules was 91.7%, and its specificity was 100%.
"The most important result of our study is the nearly complete overlap of CT and MRI findings [in patients with COVID-19]," the group noted.
Overall, the study points to MRI as a useful option for COVID-19 diagnostic follow-up, according to the researchers.
"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," they concluded. "Especially, MRI is important to assess lung pathology over time as more is learned about COVID and the long-term impact on health."
