MRI of the thorax during whole‐body MRI: Evaluation of different MR sequences and comparison to thoracic multidetector computed tomography (MDCT)

Abstract

Purpose:To evaluate the accuracy of four MR sequences used as part of a whole-body MRI protocol to detect pulmonary lesions in cancer patients. Materials and Methods:A total of 31 oncology patients were imaged in a 1.5T MR scanner (Magnetom Avanto; Siemens Medical Solutions, Germany) for whole-body staging. MR chest imaging included: axial and coronal T2-weighted (T2w)-short-tau inversion-recovery (STIR), axial T2w turbo spin-echo (TSE), and contrast-enhanced (CE) three-dimensional (3D) volumetric interpolated breathhold examination (VIBE). Multidetector computed tomography (MDCT) of the thorax served as the reference standard. The MDCT and MR images were evaluated independently by two radiologists. Comparative analysis was performed per lesion, per lobe, and per patient. Sensitivity, specificity, and predictive values were determined.Results: Compared to MDCT that detected 268 pulmonary lesions ranging from 2 to 75 mm in diameter, the MR sensitivities were 91.1%, 92.5%, 90.8%, and 87.3% for the coronal STIR, the axial STIR, the axial T2w-TSE, and the axial CE 3D-VIBE, respectively. Undetected pulmonary lesions were either calcified or smaller than 10 mm in the axial diameter. With coronal STIR, six false-positive findings were detected; with axial STIR, 14 were detected; with axial T2w-TSE, 10 were detected; and with 3D-VIBE, seven were detected. Conclusion:Pulmonary MRI is feasible as part of a wholebody MRI protocol. In our study, STIR images achieved high accuracy compared to chest MDCT for pulmonary lesions of 3 mm in size or larger. IN MALIGNANT DISEASES, therapeutic options as well as the patient prognosis strongly depend on the tumor stage. Following recent developments in MR hardware, such as faster MR gradients, moving table technology, and multielement coil designs, MRI of the entire body in a single session is being increasingly utilized as an attractive alternative to computed tomography (CT) for whole-body tumor staging without exposing the patients to radiation (1,2). Due to its high soft-tissue contrast, the diagnostic accuracy of MRI is recognized in the musculoskeletal system, the head, the neck, and the abdomen (2-5). In the thorax, MRI has been used to assess tumors invading the chest wall and for mediastinal and cardiac tumors (6,7). For pulmonary imaging, MR is still perceived as inferior to multidetector CT (MDCT). However, as pulmonary lesion detection is an integral part of whole-body cancer imaging studies, a limited diagnostic accuracy in pulmonary staging could severely hamper the value of whole-body MRI of cancer patients.Recent MRI studies reported encouraging results for the detection of pulmonary nodules larger than 5-8 mm in diameter using single fast breathhold (BH) MR sequences in a limited number of patients (4,5,8 -11). Schroeder et al (11), for example, compared the diagnostic performance of a combined set of axial and coronal half-Fourier acquisition single-shot turbo spin-echo (HASTE) sequences with MDCT in a series of 30 patients and found a sensitivity for the detection ...

Whole-body MRI at 1.5 T and 3 T compared with FDG-PET-CT for the detection of tumour recurrence in patients with colorectal cancer

“…However, these lesions were very small in size (<4 mm), only just visible by WB-MRI, showed partial calcification in CT as well as absent FDG uptake on PET and therefore were difficult to interpret. Limited assessment and impaired diagnostic accuracy of lung nodules below 6 mm in both CT (69%) or MRI (43%) and a reduced sensitivity of PET for small-sized lung lesions has been previously described in the literature [30][31][32]. As a result of breathing-induced movement of lung parenchyma and depending on the resolution of the PET component, FDG activity can often be underestimated in small lung metastases or show no uptake at all.…”

Lung Cancer

“…The detection rates or sensitivities of MR imaging using various sequences on 1.5 and 3.0 T systems have ranged from 36.0 to 96.0% (Kersjes et al 1997;Vogt et al 2004;Schroeder et al 2005;Luboldt et al 2006;Bruegel et al 2007;Regier et al 2007;Yi et al 2007;Frericks et al 2008;Koyama et al 2008;Sommer et al 2014). The study with 150 subjects considering as the large population to date compared CT and MR imaging on a 1.5 T system demonstrated that the overall detection rate of thin-section CT (97%) was superior to that of respiratory-triggered STIR turbo SE imaging (82.5%), although there were no significant differences between the methods in the detection rate for all types of malignant nodules (Koyama et al 2008).…”

Whole-Body MR Imaging for Staging of Malignant Tumors in Pediatric Patients: Results of the American College of Radiology Imaging Network 6660 Trial

“…In part, this was based on the practical consideration that the required sample size would be unachievable. In addition, although there was an a priori belief among the nodules, but smaller lesions (, 10 mm in diameter) may go undetected (15,29). Similarly, prior reports in patients with lymphoma have shown that sensitivity with whole-body MR imaging is 92%-100% for detecting nodes between 10 and 12 mm in diameter, versus a sensitivity of 67% for nodes between 6 and 12 mm in diameter and 11% for nodes between 1 and 6 mm in diameter (28,30).…”