Evaluation of Optimal Post-Injection Timing of Hypoxic Imaging with 18F-Fluoromisonidazole-PET/CT

Mitsue Kawamura; Michio Yoshimura; Yoichi Shimizu; Kohei Sano; Takayoshi Ishimori; Yuji Nakamoto; Takashi Mizowaki; Masahiro Hiraoka

doi:10.1007/s11307-021-01580-6

Evaluation of Optimal Post-Injection Timing of Hypoxic Imaging with ¹⁸F-Fluoromisonidazole-PET/CT

Mol Imaging Biol. 2021 Aug;23(4):597-603. doi: 10.1007/s11307-021-01580-6. Epub 2021 Jan 21.

Authors

Mitsue Kawamura¹, Michio Yoshimura², Yoichi Shimizu³, Kohei Sano³, Takayoshi Ishimori⁴, Yuji Nakamoto⁴, Takashi Mizowaki¹, Masahiro Hiraoka⁵

Affiliations

¹ Department of Radiation Oncology and Image-applied Therapy, Graduate School of Medicine, Kyoto University, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto, 606-8507, Japan.
² Department of Radiation Oncology and Image-applied Therapy, Graduate School of Medicine, Kyoto University, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto, 606-8507, Japan. myossy@kuhp.kyoto-u.ac.jp.
³ Division of Clinical Radiology Service, Kyoto University Hospital, Kyoto, Japan.
⁴ Department of Diagnostic Imaging and Nuclear Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
⁵ Department of Radiation Oncology, Japanese Red Cross Wakayama Medical Center, Wakayama, Japan.

PMID: 33475945
DOI: 10.1007/s11307-021-01580-6

Abstract

Purpose: Positron emission tomography (PET)/computed tomography (CT) using ¹⁸F-fluoromisonidazole (FMISO) has been used as an imaging tool for tumour hypoxia. However, it remains unclear whether they are useful when scanning is performed earlier, e.g. at 2-h post-injection with a high sensitivity PET scanner. This study aimed to investigate the relationship between quantitative values in ¹⁸F-fluoromisonidazole (¹⁸F-FMISO)-PET obtained at 2- and 4-h post-injection in patients with head and neck cancer.

Procedures: We enrolled 20 patients with untreated locally advanced head and neck cancer who underwent ¹⁸F-FMISO-PET/CT scan between August 2015 and March 2018 at our institute. Image acquisition was performed 2 h and 4 h after ¹⁸F-FMISO administration using a combined PET/CT scanner. The SUVmax, SUVmean, SUVpeak, tumour-to-blood ratio (TBR), tumour-to-muscle ratio (TMR), metabolic tumour volume (MTV), and total lesion hypoxia (TLH) were measured in the region of interest of the primary tumour. We evaluated the between-image Spearman's rank correlation coefficients and percentage differences in the quantitative values. The locations of the maximum uptake pixel were identified in both scans, and the distance between them was measured.

Results: The mean (SD) SUVmax at 2 h and 4 h was 2.2(0.7) and 2.4(0.8), respectively. The Spearman's rank correlation coefficients (ρ) and mean (SD) of the percentage differences of the measures were as follows: SUVmax (0.97; 7.0 [5.1]%), SUVmean (0.97; 5.2 [5.8]%), SUVpeak (0.94; 5.3 [4.7]%), TBR (0.96; 14.2 [9.8]%), TMR (0.96; 14.7 [8.4]%), MTV (0.98; 39.9 [41.3]%), and TLH (0.98; 40.1 [43.4]%). There were significant between-scan correlations in all quantitative values. The mean (SD) distance between the two maximum uptake pixels was 7.3 (5.3) mm.

Conclusions: We observed a high correlation between the quantitative values at 2 h and 4 h. When using a combined high-quality PET/CT, the total examination time for FMISO-PET can be shortened by skipping the 4-h scan.

Keywords: FMISO-PET; Head and neck cancer; Post-injection timing; Tumour hypoxia.

Publication types

Evaluation Study
Research Support, Non-U.S. Gov't

MeSH terms

Adult
Aged
Aged, 80 and over
Cell Hypoxia / physiology*
Female
Fluorine Radioisotopes
Head and Neck Neoplasms / diagnostic imaging*
Head and Neck Neoplasms / metabolism
Head and Neck Neoplasms / pathology
Humans
Male
Middle Aged
Misonidazole / analogs & derivatives*
Positron Emission Tomography Computed Tomography / methods*
Radiopharmaceuticals
Tumor Burden

Substances

Fluorine Radioisotopes
Radiopharmaceuticals
fluoromisonidazole
Misonidazole