PET/MRI vs PET/CT for the Detection of Lung Nodules

Hossein Jadvar, MD, PhD, MPH, MBA


November 26, 2013

Pulmonary Nodules in Patients With Primary Malignancy: Comparison of Hybrid PET/MR and PET/CT Imaging

Chandarana H, Heacock L, Rakheja R, et al
Radiology. 2013;268:874-881


The goal of this investigation was to compare the diagnostic performance of radial T1-weighted gradient-echo (radial volumetric interpolated breath-hold examination [VIBE]) MRI, PET, simultaneous hybrid PET/MRI, and hybrid PET/CT for the detection of 69 lung nodules in 32 patients with cancer of the breast, lung, ovary, endometrium, esophagus, prostate, or skin; sarcoma; osteosarcoma; or lymphoma.

The sensitivity of PET/MRI was 70.3% for all nodules, 95.6% for fluorodeoxyglucose (FDG)-avid nodules, and 88.6% for nodules ≥ 0.5 cm. PET/MRI had significantly higher sensitivity than MRI alone for FDG-avid nodules and higher sensitivity than PET alone for all nodules. There was a strong correlation between measured metabolic activity by PET/CT and PET/MRI. The authors concluded that simultaneous PET/MRI with radial VIBE sequence has high sensitivity for the detection of nodules ≥ 0.5 cm in diameter and FDG-avid nodules.


Hybrid PET/MRI systems may provide competitive advantages over PET/CT in some clinical settings, and they are now available on the market.[1,2,3] This study from New York University addressed concerns regarding the perceived limitations of PET/MRI compared with PET/CT in depicting lung nodules.

This straightforward clinical study design showed that PET/MRI is generally useful in detecting lung nodules compared with PET/CT, although it may be limited for small non-FDG avid nodules. Small nodules, including micronodules (miliary pattern), may also be missed on PET. However, they are generally depicted well on CT.

Therefore, PET/MRI may have a disadvantage in the detection of micronodularity and possibly for lymphangitic metastatic spread. Nevertheless, it appears that for most clinical situations, PET/MRI offers adequate diagnostic performance for the detection of lung disease, although occasional chest CT may still be needed.



Comments on Medscape are moderated and should be professional in tone and on topic. You must declare any conflicts of interest related to your comments and responses. Please see our Commenting Guide for further information. We reserve the right to remove posts at our sole discretion.