Amide Proton Transfer‐Weighted Imaging in Assessing the Aggressive and Proliferative Potential of Bladder Cancer

Background Ki‐67 and human epidermal growth factor receptor 2 (HER2) are known oncogenes involved in bladder cancer (BCa) patient risk stratification. Preoperative assessment of their expression level can assist in clinical treatment decision‐making. Recently, amide proton transfer‐weighted (APTw) MRI has shown promising potential in the diagnosis of several malignancies. However, few studies reported the value of APTw imaging in evaluating Ki‐67 and HER2 status of BCa. Purpose To investigate the feasibility of APTw MRI in assessing the aggressive and proliferative potential regarding the expression levels of Ki‐67 and HER2 in BCa. Study Type Retrospective. Subjects 114 patients (mean age, 64.78 ± 11.93 [SD] years; 97 men) were studied. Field Strength/Sequence APTw MRI acquired by a three‐dimensional fast‐spin‐echo sequence at 3.0 T MRI system. Assessment Patient pathologic findings, included histologic grade and the expression status of Ki‐67 and HER2, were reviewed by one uropathologist. The APTw values of BCa were independently measured by two radiologists and were compared between high−/low‐tumor grade group, high−/low‐Ki‐67 expression group, and high−/low‐HER2 expression group. Statistical Tests The interclass correlation coefficient, independent sample t ‐test, Mann–Whitney U test, Spearman's rank correlation, and receiver operating characteristic curve (ROC) analysis were used. P < 0.05 was considered statistically significant. Results Significantly higher APTw values were found in high‐grade BCa patients (7.72% vs. 4.29%, P < 0.001), high‐Ki‐67 expression BCa patients (8.40% vs. 3.25%, P < 0.001) and HER2 positive BCa patients (8.24% vs. 5.40%, P = 0.001). APTw values were positively correlated with Ki‐67 ( r = 0.769) and HER2 ( r = 0. 356) expression status. The area under the ROC curve of the APTw values for detecting Ki‐67 and HER2 expression status were 0.883 (95% CI: 0.790–0.945) and 0.713 (95% CI: 0.592–0.816), respectively. Data Conclusions APTw MRI is a potential method to assess the biological and proliferation potential of BCa. Level of Evidence 4. Technical Efficacy Stage 2.