However, the researchers cautioned that differences among PET/MRI systems and PET/CT devices, ranging from technical specifications and scanner technologies to imaging protocols, can have an impact on detection capabilities.
Three Key Takeaways
1. Higher sensitivity of PET/MRI. The meta-analysis found that (18F) FDG PET/MRI has a significantly higher sensitivity (94 percent) compared to (18F) FDG PET/CT (77 percent) for detecting cardiac sarcoidosis, likely due to MRI’s superior soft tissue contrast and its ability to assess both metabolic activity and tissue characteristics.
2. Comparable specificity. Although (18F) FDG PET/CT showed a higher pooled specificity (90 percent) compared to (18F) FDG PET/MRI (79 percent), the difference in specificity between the two modalities was not statistically significant.
3. Impact of technical variations. The detection capabilities of PET/MRI and PET/CT can be influenced by differences in technical specifications and scanner technologies. The number of CT slices in PET/CT studies varied, which could impact performance, but such details were not available in eight of the 12 reviewed PET/CT studies, limiting a comprehensive assessment.
For example, while only four of the reviewed 12 PET/CT studies noted details on CT slices, the researchers noted variation with six-slice CT, 16-slice CT and 64-slice CT being utilized.
“These (differences) in the number of slices could potentially influence the performance of PET/CT. However, such technical details are relatively scarce in most studies, preventing us from assessing their impact on PET/CT through appropriate statistical methods,” pointed out Shen and Yang.
While PET/MRI may provide improved sensitivity for cardiac sarcoidosis, the meta-analysis authors noted that PET/CT is less expensive and offers greater availability. They suggested that future research should examine the cost-effectiveness of the modalities for diagnosing cardiac sarcoidosis.
(Editor’s note: For related content, see “FDA Clears CT-Based Tools for PE Detection and Stroke Severity Assessment,” “New Literature Review Assesses Merits of Cardiac MRI After Survival of Sudden Cardiac Arrest” and “Image IQ Quiz: 55-Year-Old Woman with Progressive Joint Pain, Fatigue and Weight Loss.”)
In regard to study limitations, the authors acknowledged the lack of comparative studies and a smaller sample size for assessment of (18F)FDG PET/MRI. The researchers also noted the majority of reviewed studies were retrospective.
