Lung cancer is the second most common malignant tumor worldwide [1]. In China, the incidence and mortality of lung cancer rank first among malignant tumors, accounting for 54.66/100,000 and 45.60/100,000 cases, respectively [2]. The diagnosis of lung cancer may be challenging considering that both lung cancer and benign lesions can present as pulmonary nodules and masses. At present, computed tomography (CT) is the most commonly used method to evaluate pulmonary nodules and masses. Some of them can be identified according to morphological characteristics and CT value of non-enhanced CT. In addition, enhancement CT can be further performed for some patients with lung nodules or masses. Previous studies have shown that the absence of significant lung nodule enhancement (≤15 HU) at CT is strongly predictive of benignity, while a lung nodule enhancement greater than 15HU at CT is indicative of malignancy [3]. However, the CT enhancement threshold cannot well distinguish part of benign and malignant pulmonary lesions.

Positron emission tomography (PET)/CT is a good method to differentiate between benign and malignant pulmonary nodules and masses. However, its major limitations are high cost and the need for radiotracers (this radiation exposure). In addition, PET/CT may also lead to false positives for some inflammatory nodules/masses [4] and false negatives for solid lung cancer (≤2 cm), bronchiolar carcinoma, and well-differentiated adenocarcinoma [5].

In recent years, MR technology has developed rapidly. Studies have shown that MR can evaluate a variety of lung lesions. For example, Ultrashort TE (UTE) and T1 radial VIBE have been used to detect small pulmonary nodules and the morphological characteristics of nodules or masses [[6], [7], [8]]. Also, T2-weighted imaging (T2WI) can be used to distinguish benign and malignant pulmonary nodules or masses [9]. In addition, diffusion-weighted imaging (DWI) can be applied to stage lung cancer [10]. MR is radiation-free and can well demonstrate hilar and mediastinal infiltration of lung cancer [11].

In this study, multiple echo trains of a turbo spin echo were acquired in a rotating, partially overlapping fashion, a process called the “blades”, which is a product name of a brand's motion insensitive turbo spin echo sequence that uses the PROPELLER k-space trajectory [12,13]. The free-breathing BLADE fat-suppressed T2 weighted turbo echo sequence (BLADE T2WI) can effectively reduce respiratory movement and vascular pulsation artifacts in the chest. Previous study found that BLADE T2WI provides improved myocardial visibility, less motion sensitivity, and better image quality. It may be applied in patients who have poor breath-holding capability [12]. BLADE T2WI of the prostate may help reduce motion artifact compared with standard T2WI [14]. The performance of BLADE T2WI is superior to routine T2WI in eliminating motion artifacts for breast MR. It provides better pectoral muscle contour assessment and better signal-to-noise [15].

Therefore, this study aims to quantitatively evaluate the efficacy of MR T2-weighted Imaging (T2WI) BLADE for differentiating lung cancer (LC) and benign pulmonary nodule or mass (BPNM).