Initial results of the use of a novel semiquantitative parameter in three-phase bone scan to predict 99mTc-HMPAO-labeled leukocyte scintigraphy in patients with unilateral total knee replacement. Issue 2 (February 2021)

• Record Type: Journal Article
• Authors: Quartuccio, Natale; Panareo, Stefano; Urso, Luca; Sturiale, Letterio; Siracusa, Massimiliano; Arnone, Annachiara; Alongi, Pierpaolo; Baldari, Sergio; Bartolomei, Mirco; Arnone, Gaspare
• Is Part Of: Nuclear medicine communications. Volume 42:Issue 2(2021)
• Publication Date: 2021-02
• Subjects: infection -- knee -- leukocyte scintigraphy -- loosening -- prosthesis -- prosthesis-related infections -- radionuclide imaging -- three-phase bone scan -- total knee arthroplasty -- total knee replacement; Nuclear medicine -- Periodicals; 616.07575
• DOI: 10.1097/MNM.0000000000001321
• Languages: English
• ISSNs: 0143-3636

Abstract

Abstract : Objectives: The aim of the study was to predict the results of 99m Tc-hexamethylpropyleneamine oxime (HMPAO)-labeled autologous leukocytes scintigraphy assessing count ratios in the perfusion (Pr) and blood-pool (BPr) phase images in three-phase bone scan (3PBSr) between the prosthetic knee and the 'healthy' knee and a novel semiquantitative parameter (P/BP ratio) in patients with unilateral knee arthroplasty. Methods: Patients with unilateral knee arthroplasty and available 3PBS and 99m Tc-HMPAO-labeled autologous leukocytes scintigraphic images were searched in two hospitals (A and B). In center A, the perfusion phase was not available. Regions of interest (ROI) were delineated in the perfusion (P) and blood-pool (BP) phase images, incorporating the prosthetic region and applying an isocontour (40% of the maximum pixel activity); corresponding mirror ROIs were placed on the healthy knee. The P/BP ratio was calculated as {[(Pr/BPr) × 100] – 100}. Receiver operator curves (ROCs) were generated for each semiquantitative parameter to identify the optimal cutoff for predicting the results of the autologous leukocytes scintigraphy. Results: In the whole group (79 patients), BPr demonstrated an area under the curve (AUC) of 0.722 (optimal cutoff = 1.43). In center A (52 patients), BPr demonstrated an AUC of 0.737 (cutoff = 1.43), whereas, in center B (27 patients), AUC for BPr was 0.718 (cutoff = 1.6). A better diagnostic performance was obtained selecting Pr (AUC = 0.918; cutoff = 2.34) and P/BP ratio (AUC = 0.947; cutoff = 26.5%) for the discrimination between septic and aseptic loosening. Conclusions: The novel P/BP ratio seems to be a promising semiquantitative parameter to predict septic loosening. These findings warrant confirmation in larger patient samples.