{'fraction_non_alphanumeric': 0.05272727272727273, 'fraction_numerical': 0.02666666666666667, 'mean_word_length': 5.16044776119403, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Locally recurrent prostate cancer after high-dose-rate brachytherapy: the value of diffusion-weighted imaging, dynamic contrast-enhanced MRI, and T2-weighted imaging in localizing tumors.

OBJECTIVE
The purpose of this article is to retrospectively evaluate the utility of prostate MRI for detecting locally recurrent prostate cancer after high-dose-rate (HDR) brachytherapy.


MATERIALS AND METHODS
Sixteen men with biochemical failure after HDR brachytherapy for prostate cancer underwent prostate MRI, including T2-weighted imaging, dynamic contrast-enhanced MRI (DCE-MRI), and diffusion-weighted imaging (DWI), using a 1.5-T MRI unit before 12-core-specimen biopsy. Two radiologists in consensus assessed the presence of tumor on each sequence within eight regions of the prostate (six from the peripheral zone [PZ] and two from the transition zone [TZ]) on the basis of biopsy.


RESULTS
Biopsy revealed locally recurrent prostate cancer in 22 (17 in PZ and five in TZ) of 128 regions (17.2%). The sensitivity, specificity, and accuracy of each MRI method in the detection of recurrent tumor were 27%, 99%, and 87%, respectively, for T2-weighted imaging; 50%, 98%, and 90%, respectively, for DCE-MRI; and 68%, 95%, and 91%, respectively, for DWI. The sensitivity of DWI in detecting recurrent tumor was significantly higher than that of T2-weighted imaging (p = 0.004). Multiparametric MRI achieved the highest sensitivity (77%) but with slightly decreased specificity (92%).


CONCLUSION
These results indicate that a multiparametric MRI protocol that includes DWI provides a sensitive method to detect local recurrence after HDR brachytherapy.