Convolutional Neural Networks for Automated PET/CT Detection of Diseased Lymph Node Burden in Patients with Lymphoma

Amy J Weisman1, Minnie W Kieler1, Scott B Perlman1

  • 1Department of Medical Physics, University of Wisconsin-Madison, Madison Wis (A.J.W., R.J.); Department of Radiology, Wisconsin Institutes for Medical Research, University of Wisconsin-Madison, 1111 Highland Ave, Room 1005, Madison, WI 53705 (M.W.K., S.B.P., T.J.B.); Department of Hematology, Rigshospitalet, Copenhagen, Denmark (M.H.); Faculty of Mathematics and Physics, University of Ljubljana, Ljubljana, Slovenia (R.J.); and Department of Radiology and Medical Imaging, University of Virginia, Charlottesville, Va (L.K.).

Insights

Convolutional neural networks (CNNs) show promise in automatically detecting lymphoma-involved lymph nodes on 18F-FDG PET/CT scans, achieving performance comparable to human experts.

Area of Science:

  • Medical Imaging
  • Artificial Intelligence
  • Oncology

Background:

  • Lymphoma staging and treatment response assessment rely on accurate detection of involved lymph nodes.
  • Manual analysis of 18F-FDG PET/CT scans for lymph node involvement can be time-consuming and subject to inter-observer variability.

Purpose of the Study:

  • To develop and evaluate a deep learning model using convolutional neural networks (CNNs) for automated detection of lymph nodes in patients with lymphoma on 18F-FDG PET/CT images.
  • To assess the performance of the CNN model in terms of true-positive rate (TPR) and false-positive (FP) findings.

Main Methods:

  • A retrospective study involving 90 lymphoma patients with baseline 18F-FDG PET/CT scans.
  • Segmentation of involved lymph nodes by a nuclear medicine physician.
  • Training an ensemble of 3D patch-based, multiresolution pathway CNNs using fivefold cross-validation.
  • Performance evaluation using TPR and FP counts, with comparison to inter-physician agreement in a subset of 20 patients.

Main Results:

  • The CNN model achieved an 85% TPR with an average of 4 FP findings per patient across all 90 patients.
  • Performance varied across patients, with TPR ranging from 33% to 100%.
  • In a comparison with a second physician, the CNN achieved a 90% TPR at 3.7 FP findings per patient, comparable to the second reader's 96% TPR at 3.7 FP findings.

Conclusions:

  • An ensemble of 3D CNNs demonstrated a performance in detecting lymph nodes that is nearly comparable to the variability between two expert physicians.
  • This study represents a significant first step towards automated PET/CT assessment for lymphoma.
  • The findings suggest the potential for AI-driven tools to aid in the interpretation of oncologic imaging.
Abstract

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