Imaging of Metastatic Lymph Nodes by X-ray Phase-Contrast Micro-Tomography

Irene Zanette,Tina Binderup,Robert Feidenhans’l,Elena Reznikova,Torben Haugaard Jensen,Arvid Böttiger,Andreas Kjær,Fritz Rank,Timm Weitkamp,Martin Bech,Liselotte Højgaard,Franz Pfeiffer,Jürgen Mohr,Christian David

doi:10.1371/journal.pone.0054047

Abstract

Invasive cancer causes a change in density in the affected tissue, which can be visualized by x-ray phase-contrast tomography. However, the diagnostic value of this method has so far not been investigated in detail. Therefore, the purpose of this study was, in a blinded manner, to investigate whether malignancy could be revealed by non-invasive x-ray phase-contrast tomography in lymph nodes from breast cancer patients. Seventeen formalin-fixed paraffin-embedded lymph nodes from 10 female patients (age range 37–83 years) diagnosed with invasive ductal carcinomas were analyzed by X-ray phase-contrast tomography. Ten lymph nodes had metastatic deposits and 7 were benign. The phase-contrast images were analyzed according to standards for conventional CT images looking for characteristics usually only visible by pathological examinations. Histopathology was used as reference. The result of this study was that the diagnostic sensitivity of the image analysis for detecting malignancy was 100% and the specificity was 87%. The positive predictive value was 91% for detecting malignancy and the negative predictive value was 100%. We conclude that x-ray phase-contrast imaging can accurately detect density variations to obtain information regarding lymph node involvement previously inaccessible with standard absorption x-ray imaging.

Highlights

Breast cancer is the leading cause of death in cancer among women [1]
The purpose of this study was, in a blinded manner, to investigate whether malignancy could be revealed by non-invasive x-ray phase-contrast tomography in lymph nodes from breast cancer patients
Twenty-three samples were visualized by phase-contrast microtomography

Summary

Introduction

Diagnosis and accurate staging of the disease are crucial for proper treatment and improved prognosis It is of major importance whether the cancer is confined to the breast or has spread to the adjacent lymph nodes. The distribution of the radiotracer is visualized by a gamma camera image, revealing the lymph nodes that are draining the breast tissue with the tumor. These local lymph nodes, usually numbering between one and three, are called the sentinel nodes. The surgeon identifies the sentinel node with a small Geiger probe and removes the nodes for investigation by the pathologist. If the nodes show histological metastatic deposits, an axillary dissection is performed [3]

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