Yan-Jun Wang, Xiu-Qiong Lang, Dan Wu, Yu-Qin He, Chun-Hui Lan, Xiao-Xiao, Bin Wang, Duo-Wu Zou, Ji-Min Wu, Yong-Bin Zhao, Peter W Dettmar, Dong-Feng Chen,and Min Yang. J Neurogastroenterol Motil 1999;0:. https://doi.org/10.5056/jnm19032

Purpose: Accurate evaluation of intestinal lesions and severity assessment of ulcerative colitis (UC) are crucial for therapeutic strategies and prognosis. This study aims to compare the efficacy of ¹⁸ F-FAPI and ¹⁸ F-FDG PET/CT in the evaluation of intestinal lesions and disease activity assessment of UC. Methods: This is a prospective cohort study, and patients with newly diagnosed or relapsed UC were enrolled. All participants underwent ¹⁸ F-FAPI PET/CT, ¹⁸ F-FDG PET/CT, abdominal contrast-enhanced CT, and colonoscopy within 1 week. Mayo Endoscopic Subscore (MES) was used as the reference standard for identification and severity assessment of intestinal lesions. Target-to-background ratio (TBR) of each segment in ¹⁸ F-FAPI/ ¹⁸ F-FDG PET/CT and global ¹⁸ F-FAPI/ ¹⁸ F-FDG PET/CT score were computed to represent the activity of independent segments and all segments, respectively. Before examinations, partial Mayo score was calculated based on clinical manifestations of patients, and levels of C-reactive protein, interleukin-6, erythrocyte sedimentation rate, platelet, and hemoglobin were determined. Finally, all data were analyzed to compare the efficacy of ¹⁸ F-FAPI and ¹⁸ F-FDG PET/CT in the evaluation of intestinal lesions and disease activity in UC. Results: A total of 113 intestinal segments (including 90 lesion segments) were evaluated among 23 participants. Through receiver operating characteristic (ROC) analysis, ¹⁸ F-FAPI PET/CT showed significantly superior performance in detecting intestinal lesions compared with ¹⁸ F-FDG PET/CT ( P = 0.046) and abdominal contrast-enhanced CT ( P = 0.007). The correlations between FAPI-TBR and MES ( R ² = 0.75) and abdominal contrast-enhanced CT score ( R ² = 0.55) were stronger than those of FDG-TBR. ¹⁸ F-FAPI PET/CT showed superior discriminative capacity across different disease activity levels at both segmental ( P < 0.001) and patient-level ( P < 0.05) in intergroup comparison. The global ¹⁸ F-FAPI PET/CT score was significantly correlated with other activity indicators ( r = 0.49–0.76). Moreover, ¹⁸ F-FAPI PET/CT was also significantly superior to ¹⁸ F-FDG PET/CT ( P < 0.001) and abdominal contrast-enhanced CT ( P = 0.001) in detecting active lesions according to ROC analysis. Conclusions: The efficacy of ¹⁸ F-FAPI PET/CT in the evaluation of intestinal lesions and disease activity assessment of UC was superior to that of ¹⁸ F-FDG PET/CT. ¹⁸ F-FAPI PET/CT also correlated well with endoscopy, abdominal contrast-enhanced CT, clinical manifestations, and biomarkers. Therefore, ¹⁸ F-FAPI PET/CT may be a promising method for noninvasive assessment of disease activity of UC.

Objective: Obstructed defecation syndrome (ODS) is a chronic constipation subtype. Conventional tests are limited by non-physiological conditions and poor correlation with symptoms. This study investigated anorectal dynamics and dyssynergia phenotypes in patients with ODS using Fecobionics. Methods: This study was designed as a prospective observational study including 10 control subjects and 25 patients with ODS. All measurements were performed according to a predefined protocol. All patients with ODS underwent clinical evaluation, anorectal manometry (ARM) and defecography. Fecobionics recorded anorectal pressures, sensation and expulsion performance. Expulsion dynamics were further analysed using preload–afterload diagrams to characterise dyssynergia subtypes. Results: Compared with the control group, the ODS group showed prolonged expulsion time (76 (23–120) vs 18.7 s (10.6–34), p<0.01), reduced effective propulsive force (P_delta) (26.2 (8.6–35.9) vs 48.2 cmH₂O (32.5–88.0), p<0.01), increased number of contractions (7 (4–14) vs 2.5 (1.3–3.8), p<0.01) and higher paradoxical contraction rates (71% (50–100) vs 0% (0–44), p<0.01). ARM during attempted evacuation (push) demonstrated lower anal relaxation rates in the ODS group (16% (12–37) vs 36% (27–44), p<0.03). Correlation analyses demonstrated that impaired Fecobionics metrics were associated with greater symptom burden. Three dyssynergia phenotypes were identified: multiple simultaneous contractions, insufficient or delayed anal relaxation and persistently elevated outlet pressure. Conclusion: Fecobionics enables integrated and physiologically relevant assessment of anorectal function and identifies distinct dyssynergia phenotypes in ODS, reflecting heterogeneous mechanisms of outlet obstruction with implications for individualised management. Study registration: ChiCTR2300078807.