Computed <scp>DWI</scp> MRI Results in Superior Capability for <scp>N‐Stage</scp> Assessment of <scp>Non‐Small</scp> Cell Lung Cancer Than That of Actual <scp>DWI</scp>, <scp>STIR</scp> Imaging, and <scp>FDG‐PET</scp>/<scp>CT</scp>
Yoshiharu Ohno, Masao Yui, Daisuke Takenaka, Takeshi Yoshikawa, Hisanobu Koyama, Yoshimori Kassai, Kaori Yamamoto, Yuka Oshima, Nayu Hamabuchi, Satomu Hanamatsu, Yuki Obama, Takahiro Ueda, Hirotaka Ikeda, Hidekazu Hattori, Kazuhiro Murayama, Hiroshi Toyama
Abstract
Background Computed diffusion‐weighted imaging (cDWI) is a mathematical computation technique that generates DWIs for any b ‐value by using actual DWI (aDWI) data with at least two different b ‐values and may improve differentiation of metastatic from nonmetastatic lymph nodes. Purpose To determine the appropriate b ‐value for cDWI to achieve a better diagnostic capability for lymph node staging (N‐staging) in non‐small cell lung cancer (NSCLC) patients compared to aDWI, short inversion time (TI) inversion recovery (STIR) imaging, or positron emission tomography with 2‐[fluorine‐18] fluoro‐2‐deoxy‐ d ‐glucose combined with computed tomography (FDG‐PET/CT). Study Type Prospective. Subjects A total of 245 (127 males and 118 females; mean age 72 years) consecutive histopathologically confirmed NSCLC patients. Field Strength/Sequence A 3 T, half‐Fourier single‐shot turbo spin‐echo sequence, electrocardiogram (ECG)‐triggered STIR fast advanced spin‐echo (FASE) sequence with black blood and STIR acquisition and DWI obtained by FASE with b ‐values of 0 and 1000 sec/mm 2 . Assessment From aDWIs with b ‐values of 0 and 1000 (aDWI 1000 ) sec/mm 2 , cDWI using 400 (cDWI 400 ), 600 (cDWI 600 ), 800 (cDWI 800 ), and 2000 (cDWI 2000 ) sec/mm 2 were generated. Then, 114 metastatic and 114 nonmetastatic nodes (mediastinal and hilar lymph nodes) were selected and evaluated with a contrast ratio (CR) for each cDWI and aDWI, apparent diffusion coefficient (ADC), lymph node‐to‐muscle ratio (LMR) on STIR, and maximum standard uptake value (SUV max ). Statistical Tests Receiver operating characteristic curve (ROC) analysis, Youden index, and McNemar's test. Results Area under the curve (AUC) of CR 600 was significantly larger than the CR 400 , CR 800 , CR 2000 , aCR 1000 , and SUV max . Comparison of N‐staging accuracy showed that CR 600 was significantly higher than CR 400 , CR 2000 , ADC, aCR 1000 , and SUV max , although there were no significant differences with CR 800 ( P = 0.99) and LMR ( P = 0.99). Data Conclusion cDWI with b ‐value at 600 sec/mm 2 may have potential to improve N‐staging accuracy as compared with aDWI, STIR, and PET/CT. Evidence Level 2 Technical Efficacy Stage 2