Chest PET/MRI in Solid Cancers: Comparing the Diagnostic Performance of a Free-Breathing 3D-T1-GRE Stack-of-Stars Volume Interpolated Breath-Hold Examination (StarVIBE) Acquisition With That of a 3D-T1-GRE Volume Interpolated Breath-Hold Examination (VIBE) for Chest Staging During Whole-Body PET/MRI.

Abstract

Whole-body positron emission tomography/magnetic resonance imaging (WB-PET/MRI) is increasingly used in oncology. However, chest staging remains challenging. To compare the diagnostic performance of a free-breathing 3D-T1-GRE stack-of-stars volume interpolated breath-hold examination (StarVIBE) with that of a 3D-T1-GRE volume interpolated breath-hold examination (VIBE) during WB-PET/MRI for chest staging. Retrospective, cohort study. One hundred and twenty-three patients were referred for initial staging of solid cancer, 46 of whom had pulmonary nodules and 14 had pulmonary metastasis. Free-breathing 3D-T1-GRE stack-of-stars (StarVIBE) and Cartesian 3D-T1-GRE VIBE at 3.0 T. Image quality was assessed using a 4-point scale and using the signal-to-noise ratio (SNR) of lung parenchyma and contrast-to-noise ratio (CNR) of pulmonary nodules. Diagnostic performances of both sequences were determined by three independent radiologists for detection of pulmonary nodules, lymph node involvement, and bone metastases using chest CT, pathology, and follow-up as reference standards. Paired Student's t-test; chi-squared; Fisher's exact test. A P value <0.05 was considered statistically significant. StarVIBE quality was judged as better in 34% of cases and at least equivalent to VIBE in 89% of cases, with significantly higher quality scores (4 [4-4] vs. 3 [3-4], respectively). SNR and CNR values were significantly higher with StarVIBE (8 ± 1.3 and 9.7 ± 4.6, respectively) than with VIBE (1.8 ± 0.2 and 5.5 ± 3.3, respectively). Compared to VIBE, StarVIBE showed significantly higher sensitivity (73% [95% CI 62-82] vs. 44% [95% CI 33-55], respectively) and specificity (95% [95% CI 88-99] vs. 67% [95% CI 56-77]) for pulmonary nodules detection and significantly higher sensitivity (100% [95% CI 89-100] vs. 67% [95% CI 48-82], respectively) for detection of lymph node involvement. Sensitivities for bone metastases detection were not significantly different (100% [95% CI 88-100] vs. 82% [95% CI 63-94], P=0.054). Owing to improved SNR and CNR and spatial resolution, a free-breathing 3D stack-of-stars T1-GRE sequence improves chest staging in comparison with standard 3D-T1-GRE VIBE and may be integrated in WB-PET/MRI acquisitions for initial staging of solid cancer. 3 TECHNICAL EFFICACY: Stage 2.