Machine Learning Facilitates Hotspot Classification in PSMA-PET/CT with Nuclear Medicine Specialist Accuracy

• Main Authors: Sobhan Moazemi, Zain Khurshid, Annette Erle, Susanne Lütje, Markus Essler, Thomas Schultz, Ralph A. Bundschuh
• Format: Article
• Language: English
• Published: MDPI AG 2020-08-01
• Series: Diagnostics
• Subjects: prostate cancer (PC); prostate-specific membrane antigen (PSMA); positron emission tomography (PET); computed tomography (CT); machine learning (ML)
• Online Access: https://www.mdpi.com/2075-4418/10/9/622

Gallium-68 prostate-specific membrane antigen positron emission tomography <b>(</b>⁶⁸Ga-PSMA-PET) is a highly sensitive method to detect prostate cancer (PC) metastases. Visual discrimination between malignant and physiologic/unspecific tracer accumulation by a nuclear medicine (NM) specialist is essential for image interpretation. In the future, automated machine learning (ML)-based tools will assist physicians in image analysis. The aim of this work was to develop a tool for analysis of ⁶⁸Ga-PSMA-PET images and to compare its efficacy to that of human readers. Five different ML methods were compared and tested on multiple positron emission tomography/computed tomography (PET/CT) data-sets. Forty textural features extracted from both PET- and low-dose CT data were analyzed. In total, 2419 hotspots from 72 patients were included. Comparing results from human readers to those of ML-based analyses, up to 98% area under the curve (AUC), 94% sensitivity (SE), and 89% specificity (SP) were achieved. Interestingly, textural features assessed in native low-dose CT increased the accuracy significantly. Thus, ML based on ⁶⁸Ga-PSMA-PET/CT radiomics features can classify hotspots with high precision, comparable to that of experienced NM physicians. Additionally, the superiority of multimodal ML-based analysis considering all PET and low-dose CT features was shown. Morphological features seemed to be of special additional importance even though they were extracted from native low-dose CTs.