Head-to-head comparison of [¹⁸F]AlF-NOTA-FAPI-04 PET/CT and CE-MRI for diagnosing biliary tract cancer: a...

To evaluate the diagnostic performance of [¹⁸F]AlF-NOTA-FAPI-04 PET/CT in detecting primary and metastatic lesions in biliary tract cancer (BTC) and to compare it with contrast-enhanced (CE) MRI.

A total of 46 patients with suspected BTC were enrolled, all of whom underwent [¹⁸F]AlF-NOTA-FAPI-04 PET/CT and abdominal CE-MRI examinations. Histopathological findings, typical imaging features, follow-up imaging, and comprehensive clinical assessments were used as reference standards. McNemar's test was used to compare diagnostic performance; tracer uptake between paired samples was analyzed with the Wilcoxon signed-rank test or paired t-test.

In total, 46 participants (mean age 61.5 ± 9.91 years) were evaluated. In the patient-based comparison, [¹⁸F]AlF-NOTA-FAPI-04 PET/CT and CE-MRI demonstrated comparable sensitivity in detecting primary tumors (42/44 [95%] vs. 44/44 [100%], p = 0.480), lymph node metastases (20/21 [95%] vs. 18/21 [86%], p = 0.480), and distant metastases (12/12 [100%] vs. 9/12 [75%], p = 0.064). However, in detecting lymph node metastases, [¹⁸F]AlF-NOTA-FAPI-04 PET/CT achieved higher specificity (25/25 [100%] vs. 19/25 [76%], p = 0.041) and accuracy (45/46 [98%] vs. 37/46 [80%], p = 0.013) than CE-MRI.

The findings of this study demonstrate that [¹⁸F]AlF-NOTA-FAPI-04 PET/CT and abdominal CE-MRI exhibit comparable sensitivity in detecting primary lesions and metastases in BTC. However, [¹⁸F]AlF-NOTA-FAPI-04 PET/CT demonstrated superior specificity and accuracy in lymph node detection and effectively overcame the limitations of abdominal CE-MRI in evaluating distant metastases across the whole body.