Added value of diffusion-weighted magnetic resonance imaging in the diagnosis of recurrent cholangiocarcinoma

Abstract

Distinguishing recurrent cholangiocarcinoma lesions from postoperative fibrosis or biliojejunostomy lesions using contrast-enhanced computed tomography (CECT) alone is challenging. This study examined the value of adding diffusion-weighted magnetic resonance imaging (DWI) to CECT for the detection of cholangiocarcinoma recurrence. This single-institution retrospective analysis included 33 patients who underwent cholangiocarcinoma resection between January 2016 and December 2020. Of the patients, 20 were in the recurrence group and 13 were in the non-recurrence group. Two observers independently reviewed the CECT images and subsequently reviewed the combined CECT and DWI images (b-value, 1000 s/mm²), with each image reviewed twice. The diagnostic performance was evaluated using receiver operating characteristic (ROC) curve analysis. Kappa statistics were used to evaluate agreement. The diagnostic performance (area under the ROC curve [AUC]) of both observers improved after the addition of DWI; the AUC improved from 0.614 to 0.918 (P = 0.003) in the first session and from 0.820 to 0.928 (P = 0.20) in the second session for Observer A, whereas it improved from 0.566 to 0.858 (P < 0.001) in the first session and from 0.753 to 0.930 (P = 0.02) in the second session for Observer B. The intraobserver and interobserver agreements improved after the addition of DWI; the kappa value improved from 0.586 to 0.656 for Observer A, from 0.371 to 0.838 for Observer B, from 0.308 to 0.766 in the first session, and from 0.464 to 0.620 in the second session. Adding DWI to CECT improves the detection of cholangiocarcinoma recurrence compared to CECT alone.

Keywords: bile ducts; cholangiocarcinoma; computed tomography; diffusion-weighted imaging; magnetic resonance imaging.

Fig. 1

CT and MRI in a 52-year-old man with recurrence at the site of biliojejunostomy and intrapancreatic bile duct four years after surgery for hilar cholangiocarcinoma The recurrent lesion at the biliojejunostomy site (arrows) displays isoattenuation at the surrounding hepatic parenchyma on pre-contrast CT (a) and CECT (b). The lesion exhibits hyperintensity on DWI (c) and isointensity on ADC imaging (b-value = 1000 s/mm²) (d) compared with the surrounding hepatic parenchyma. The recurrent lesion in the intrapancreatic bile duct (arrowheads) shows the same attenuation as the surrounding pancreatic parenchyma on pre-contrast CT (e) and CECT (f). The lesion exhibits hyperintensity on DWI (g) and hypointensity on ADC imaging (h) relative to the surrounding pancreatic parenchyma. ADC: apparent diffusion coefficient CECT: contrast-enhanced CT CT: computed tomography DWI: diffusion-weighted imaging MRI: magnetic resonance imaging

Fig. 2

CT and MRI in a 71-year-old man with recurrence at the site of biliojejunostomy nine months after surgery for hilar cholangiocarcinoma The recurrent lesion (arrows) shows low attenuation compared to the surrounding hepatic parenchyma or jejunum on pre-contrast CT (a) and CECT (b). The lesion exhibits hyperintensity on DWI (b-value = 1000 s/mm²) (c) and hypointensity on ADC imaging (d) relative to the surrounding hepatic parenchyma or jejunum. ADC: apparent diffusion coefficient CECT: contrast-enhanced CT CT: computed tomography DWI: diffusion-weighted imaging MRI: magnetic resonance imaging

Fig. 3

The AUC of receiver operating characteristic analysis The AUC improved from 0.614 to 0.918 (P = 0.003) in the first session and from 0.820 to 0.928 (P = 0.20) in the second session for Observer A, and from 0.566 to 0.858 (P < 0.001) in the first session and from 0.753 to 0.930 (P = 0.02) in the second session for Observer B. AUC: area under the curve * statistical significance (P < 0.05)

Fig. 4

Comparison of the DR on CECT and SIR on DWI The SIR on DWI (median, 0.847; interquartile range, 0.405–1.657) was significantly higher than the DR on CECT (median, 0.332; interquartile range, 0.233–0.482) (P < 0.001). CECT: contrast-enhanced computed tomography DR: density ratio DWI: diffusion-weighted imaging SIR: signal intensity ratio * statistical significance (P < 0.05)