Detection and quantification of focal uptake in head and neck tumours: 18F-FDG PET/MR versus PET/CT

Abstract

PurposeOur objectives were to assess the quality of PET images and coregistered anatomic images obtained with PET/MR, to evaluate the detection of focal uptake and SUV, and to compare these findings with those of PET/CT in patients with head and neck tumours.MethodsThe study group comprised 32 consecutive patients with malignant head and neck tumours who underwent whole-body 18F-FDG PET/MR and PET/CT. PET images were reconstructed using the attenuation correction sequence for PET/MR and CT for PET/CT. Two experienced observers evaluated the anonymized data. They evaluated image and fusion quality, lesion conspicuity, anatomic location, number and size of categorized (benign versus assumed malignant) lesions with focal uptake. Region of interest (ROI) analysis was performed to determine SUVs of lesions and organs for both modalities. Statistical analysis considered data clustering due to multiple lesions per patient.ResultsPET/MR coregistration and image fusion was feasible in all patients. The analysis included 66 malignant lesions (tumours, metastatic lymph nodes and distant metastases), 136 benign lesions and 470 organ ROIs. There was no statistically significant difference between PET/MR and PET/CT regarding rating scores for image quality, fusion quality, lesion conspicuity or anatomic location, number of detected lesions and number of patients with and without malignant lesions. A high correlation was observed for SUVmean and SUVmax measured on PET/MR and PET/CT for malignant lesions, benign lesions and organs (ρ = 0.787 to 0.877, p < 0.001). SUVmean and SUVmax measured on PET/MR were significantly lower than on PET/CT for malignant tumours, metastatic neck nodes, benign lesions, bone marrow, and liver (p < 0.05). The main factor affecting the difference between SUVs in malignant lesions was tumour size (p < 0.01).ConclusionIn patients with head and neck tumours, PET/MR showed equivalent performance to PET/CT in terms of qualitative results. Comparison of SUVs revealed an excellent correlation for measurements on both modalities, but underestimation of SUVs measured on PET/MR as compared to PET/CT.

PET/MRI: Reliability/Reproducibility of SUV Measurements

“…Despite the sometimes large differences between uptake times, most studies came to the conclusion that there was a high positive correlation for all SUV quantification metrics between both exams and that most of the differences were due to the variance in uptake time between both scans [44-48, 50, 51, 53, 54, 57, 59-61, 64]. In only two studies, some scans were performed on the PET/MR scanner first [52,58], and in two studies, all PET/MR scans were performed before PET/CT [49,56]. All other studies had a longer uptake time of 51-120 min (mean 81 min) for the PET/MR scans and showed a slight increase in SUV between both exams.…”

Lymph Node Disease and Advanced Head and Neck Imaging: A Review of the 2013 Literature

“…A study by Varoquaux et al [53] compared PET/MR and PET/CT for the detection and quantification of focal uptake in H&N tumors. They found no significant difference in qualitative results regarding image quality, fusion quality, lesion conspicuity, and anatomic location of focal uptake.…”

FDG Whole-Body PET/MRI in Oncology: a Systematic Review

“…Careful interpretation is needed for direct comparison of quantitative PET/MR and PET/CT results [86,87].…”