MRI in lung cancer: a pictorial essay

Abstract

ABSTRACT. Imaging studies play a critical role in the diagnosis and staging of lung cancer. CT and 18-fluorodeoxyglucose positron emission tomography CT (PET/CT) are widely and routinely used for staging and assessment of treatment response. Many radiologists still use MRI only for the assessment of superior sulcus tumours, and in cases where invasion of the spinal cord canal is suspected. MRI can detect and stage lung cancer, and this method could be an excellent alternative to CT or PET/CT in the investigation of lung malignancies and other diseases. This pictorial essay discusses the use of MRI in the investigation of lung cancer. . The lung remains a challenge for MRI, but this method provides excellent tissue differentiation, and new sequences have increased the temporal resolution [3], expanding the use of MRI beyond its traditional applications. MRI can currently be used for establishing tumour node metastasis (TNM) staging, lung cancer screening and assessing lung nodules for likelihood of being benign or malignant [3]. This pictorial essay discusses the use of MRI in the diagnosis and staging of lung cancer. MRI for detection and characterisation of pulmonary nodulesMultidetector CT (MDCT) is routinely used to confirm and characterise lung lesions [1]. It is a very sensitive method for the detection of pulmonary nodules, and is considered the gold standard for detection of these lesions. The sensitivity of MRI for nodules of 5 to 11 mm is between 85% and 95% [4]. Although MDCT can depict nodules as small as 1 or 2 mm, immediate action is recommended only for lesions larger than 7 or 8 mm, depending on the lung cancer risk stratification. Followup to assess growth pattern is recommended for lesions smaller than 7 mm [5]. Koyama et al [6] reported that non-contrast enhanced pulmonary MRI can effectively detect malignant nodules as thin-section MDCT (Figure 1). The overall detection rate of nodules in each MRI sequence (82.5%) was significantly lower than that of MDCT (97.0%, p,0.05), however detection rates were not significantly different for malignant nodules (p.0.05) (Figure 2). Establishing clinical TNM stageThe overall agreement of clinical TNM (cTNM) staging established by CT compared with post-operative pathological TNM (pTNM) is not significantly better than 50%. Obviously, this comparison does not take into account cases in which the cTNM contraindicates surgery, as it does for the majority of cases. CT and PET-CT are currently the modalities recommended for assessing lung cancer if radical treatment (surgery or other therapeutic modality with curative intent) is suggested [1]. However, the capabilities of MRI have not yet been properly explored. MRI assessment of T-classificationThe T-stage of a tumour is the primary determinant of its resectability [7]. Evaluation of the primary tumour includes an assessment of its size, and the presence and extent of mediastinal or chest wall involvement. Of particular importance is the distinction between T3 and T4 tumours [7]. The definition of a T3 lesion i...

TNM Staging of Non–Small Cell Lung Cancer: Comparison of PET/MR and PET/CT

“…Above all, the T stage of a tumor determinates its resectability (19,20). The ability to differentiate between stages T3 and T4 is critical for any cross-sectional imaging modality, because T4 tumors are widely considered not resectable.…”

“…Despite suggestions of using short TI inversion recovery or T2-weighted black-blood imaging for the assessment of small mediastinal nodes, MR has not gained widespread clinical acceptance for N staging of lung cancer (10,12,20,22). For PET/MR, Fraioli et al reported good accordance of PET/MR and PET/CT but did not provide data on the accuracy of PET/MR in comparison with PET/CT (6).…”

First MRI application of an active breathing coordinator

“…As recent advances in morphological and functional MRI allow for detection, characterization and staging of pulmonary nodules with a diagnostic quality equivalent to that of CT and positron emission tomography (PET)-CT (Hochhegger et al 2011), and given the ABC’s ability to arrest respiration at an individually defined and reliably reproducible inhaled or exhaled air volume, we anticipated that MR and CT images would match for the same ABC settings and patient positioning.…”

Advanced Imaging (Positron Emission Tomography and Magnetic Resonance Imaging) and Image-Guided Biopsy in Initial Staging and Monitoring of Therapy of Lung Cancer

“…24 Magnetic resonance imaging for baseline staging or assessment of treatment response in lung cancer is still investigational. However, higher magnetic field strengths (3 T), development of faster imaging sequences, advancements in digital signal processing, utilization of respiratory and cardiac gating, and better MRI contrast agents have all improved the utility of MRI for lung cancer staging.…”