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DOI: 10.1055/s-0039-1683553
Incremental diagnostic value of diffusion-weighted MRI for the detection of lymph node metastases of recurrent prostate cancer in hybrid PSMA-PET/MRI
Publication History
Publication Date:
27 March 2019 (online)
Ziel/Aim:
To determine if diffusion-weighted MRI (DWI-MRI) complements prostate specific membrane antigen (PSMA) PET in the detection of lymph node metastases in patients with biochemically recurrent prostate cancer.
Methodik/Methods:
In this retrospective study 68 patients with recurrent prostate cancer which underwent Ga-68-PSMA-PET/MRI including DWI-MRI from November 2016 to December 2017 were enrolled. Initially, a ADC threshold for differentiation of malignant and benign lymph nodes in DWI-MRI using PSMA-PET as standard of reference (SOR) was defined in asubgroup of 25 patients. This ADC threshold was subsequently applied in the remaining 43 recurrent prostate cancer patients to assess if DWI-MRI using the determined ADC threshold complements lymph node classification by PSMA-PET with interval imaging serving as SOR.
Ergebnisse/Results:
ADCmean differed significantly between malignant and benign lymph nodes (834 ± 218 × 10-6 mm2/s vs. 1617 ± 338 × 10-6 mm2/s, p < 0.001). Area under curve for ADCmean was 0.964 (p < 0.001, CI 0.889 – 1.000) with an optimal cutoff of 1278 *10-6 mm2/s (sensitivity 100%, specificity 90%) for lymph node classification. Short axis diameter was significantly smaller for lymph node metastases detected only by PSMA-PET than those also detected by DWI-MRI (4.55 ± 2.89 mm vs. 8.55 ± 3.57 mm, p < 0.001). ADCmean and SUVmax showed no correlation (r = 0.223, p = 0.212). Applying the determined ADC threshold resulted in the detection of 34 lymph node metastases compared to 30 using PMSA-PET only (+13%).
Schlussfolgerungen/Conclusions:
DWI-MRI can detect additional lymph node metastases as compared to PSMA-PET and thereby further improves the diagnostic performance of PSMA-PET/MRI in recurrent prostate cancer.
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