Comparative Study Between Integrated Positron Emission Tomography/Magnetic Resonance and Positron Emission Tomography/Computed Tomography in the T and N Staging of Hypopharyngeal Cancer: An Initial Result

Head-to-Head Comparison of the Diagnostic Performance of FDG PET/CT and FDG PET/MR in Patients With Cancer: A Systematic Review and Meta-Analysis

Background: The available evidence on the use of FDG PET/MRI performed using an integrated system in patients with cancer has grown substantially. Objective: To perform a systematic review and meta-analysis comparing the diagnostic performance of FDG PET/CT and FDG PET/MRI in patients with cancer. Evidence Acquisition: MEDLINE, EMBASE, and Cochrane Database of Systematic Reviews were searched from July 1, 2015 to January 25, 2023 for studies reporting a head-to-head comparison of the diagnostic performance of FDG PET/CT and FDG PET/MRI in patients with cancer. The two modalities' diagnostic performance was summarized, stratified by performance endpoint. For endpoints with sufficient data, meta-analysis was performed using bivariate modeling to produce summary estimates of pooled sensitivity and specificity. For remaining endpoints, reported performance in individual studies was recorded. Evidence Synthesis: The systematic review included 29 studies with a total of 1656 patients. For patient-level detection of regional nodal metastases (5 studies), pooled sensitivity and specificity for PET/MRI were 88% (95% CI, 74-95%) and 92% (95% CI, 71-98%), respectively, and for PET/CT were 86% (95% CI, 70-94%) and 86% (95% CI, 68-95%), respectively. For lesion-level detection of recurrence and/or metastases (5 studies), pooled sensitivity and specificity for PET/MRI were 94% (95% CI, 78-99%) and 83% (95% CI, 76-88%), respectively, and for PET/CT were 91% (95% CI, 77-96%) and 81% (95% CI, 72-88%), respectively. In individual studies not included in meta-analysis, PET/MRI in comparison with PET/CT showed staging accuracy in breast cancer of 98.0% versus 74.5% and in colorectal cancer of 96.2% versus 69.2%, sensitivity for primary tumor detection in cervical cancer of 93.2% versus 66.2%, and sensitivity, specificity, and accuracy for lesion-level liver metastasis detection of 91.1-98.0% versus 42.3-71.1%, 100.0% versus 83.3-98.6%, and 96.5-98.2% versus 44.7-86.7%, respectively. In three studies, management was more commonly impacted by information from PET/MRI (5.2-11.1%) than PET/CT (0.0-2.6%). Conclusions: PET/MRI showed comparable or superior diagnostic performance versus PET/CT across a range of cancers and endpoints. Clinical Impact: The findings help to identify clinical settings where PET/MRI may provide particular clinical benefit for oncologic evaluation.

Role of 18F-FDG PET/CT in Head and Neck Squamous Cell Carcinoma: Current Evidence and Innovative Applications

This article provides an overview of the use of 18F-FDG PET/CT in various clinical scenarios of head-neck squamous cell carcinoma, ranging from initial staging to treatment-response assessment, and post-therapy follow-up, with a focus on the current evidence, debated issues, and innovative applications. Methodological aspects and the most frequent pitfalls in head-neck imaging interpretation are described. In the initial work-up, 18F-FDG PET/CT is recommended in patients with metastatic cervical lymphadenectomy and occult primary tumor; moreover, it is a well-established imaging tool for detecting cervical nodal involvement, distant metastases, and synchronous primary tumors. Various 18F-FDG pre-treatment parameters show prognostic value in terms of disease progression and overall survival. In this scenario, an emerging role is played by radiomics and machine learning. For radiation-treatment planning, 18F-FDG PET/CT provides an accurate delineation of target volumes and treatment adaptation. Due to its high negative predictive value, 18F-FDG PET/CT, performed at least 12 weeks after the completion of chemoradiotherapy, can prevent unnecessary neck dissections. In addition to radiomics and machine learning, emerging applications include PET/MRI, which combines the high soft-tissue contrast of MRI with the metabolic information of PET, and the use of PET radiopharmaceuticals other than 18F-FDG, which can answer specific clinical needs.

Combined average standard uptake value and rate constant can predict expression of EGFR in hypopharyngeal squamous cell carcinoma: A pilot study with integrated PET/MRI

PURPOSE

To investigate whether the quantitative multiparameters of 18F-FDG PET/MRI can predict expression of epidermal growth factor receptor (EGFR) of hypopharyngeal squamous cell carcinoma (HSCC).

METHODS

Twenty-one patients with HSCC confirmed by biopsy underwent neck integrated 18F-FDG PET/MRI and EGFR expression detection. Quantitative parameters derived from 18F-FDG PET, difusion-weighted imaging (DWI), and dynamic contrast enhanced-magnetic resonance imaging (DCE-MRI) were measured. The efficacies of quantitative multiparameters derived from 18F-FDG PET/MRI for predicting the expression of EGFR of HSCC were evaluated.

RESULTS

The patients were divided into positive expression group (PEG, n = 14) and negative expression group (NEG, n = 7). Mann-Whitney U nonparametric test showed that SUVmean and Kep had statistical difference between PEG and NPG, while other parameters had no statistical difference. Using 14.50 and 2.10 min-1 as the threshold values, areas under the curve (AUCs) for SUVmean and Kep were 0.786 with specificity of 92.9 % and sensitivity of 57.1 %. The combined use of SUVmean and Kep had better efficacy to evaluate the expression of EGFR with AUC of 0.980, sensitivity of 92.9 %, and specificity of 100.0 %.

CONCLUSION

Combined use of SUVmean and Kep showed good performance in predicting the expression of EGFR in HSCC. Integrated 18F-FDG PET/MRI enables simultaneous acquisition of SUVmean and Kep, so it represents as a powerful tool to noninvasively and repeatably evaluate the expression of EGFR during the management of HSCC.

PET/MR Imaging in Head and Neck Cancer

Head and neck squamous cell carcinoma (HNSCC) can either be examined with hybrid PET/MR imaging systems or sequentially, using PET/CT and MR imaging. Regardless of the acquisition technique, the superiority of MR imaging compared to CT lies in its potential to interrogate tumor and surrounding tissues with different sequences, including perfusion and diffusion. For this reason, PET/MR imaging is preferable for the detection and assessment of locoregional residual/recurrent HNSCC after therapy. In addition, MR imaging interpretation is facilitated when combined with PET. Nevertheless, distant metastases and distant second primary tumors are detected equally well with PET/MR imaging and PET/CT.

MRI-based radiomics analysis for preoperative evaluation of lymph node metastasis in hypopharyngeal squamous cell carcinoma

Objective

To investigate the role of pre-treatment magnetic resonance imaging (MRI) radiomics for the preoperative prediction of lymph node (LN) metastasis in patients with hypopharyngeal squamous cell carcinoma (HPSCC).

Methods

A total of 155 patients with HPSCC were eligibly enrolled from single institution. Radiomics features were extracted from contrast-enhanced axial T-1 weighted (CE-T1WI) sequence. The most relevant features of LN metastasis were selected by the least absolute shrinkage and selection operator (LASSO) method. Univariate and multivariate logistic regression analysis was adopted to determine the independent clinical risk factors. Three models were constructed to predict the LN metastasis status: one using radiomics only, one using clinical factors only, and the other one combined radiomics and clinical factors. Receiver operating characteristic (ROC) curves and calibration curve were used to evaluate the discrimination and the accuracy of the models, respectively. The performances were tested by an internal validation cohort (n=47). The clinical utility of the models was assessed by decision curve analysis.

Results

The nomogram consisted of radiomics scores and the MRI-reported LN status showed satisfactory discrimination in the training and validation cohorts with AUCs of 0.906 (95% CI, 0.840 to 0.972) and 0.853 (95% CI, 0.739 to 0.966), respectively. The nomogram, i.e., the combined model, outperformed the radiomics and MRI-reported LN status in both discrimination and clinical usefulness.

Conclusions

The MRI-based radiomics nomogram holds promise for individual and non-invasive prediction of LN metastasis in patients with HPSCC.

Quantitative parameters derived from 18F-fluorodeoxyglucose positron emission tomography/magnetic resonance imaging can accurately estimate the histologic grade of hypopharyngeal squamous cell carcinoma preoperatively

PURPOSE

Among head and neck cancers, hypopharyngeal squamous cell carcinoma (HSCC) shows the highest malignancy, which is associated with histologic grading. This study was designed to investigate whether quantitative parameters derived from ¹⁸F-fluorodeoxyglucose positron emission tomography/magnetic resonance imaging (¹⁸F-FDG PET/MRI) can preoperatively estimate the histologic grade of HSCC.

METHODS

¹⁸F-FDG PET/MRI of neck was successfully performed in 21 patients with histologically proven HSCC including poorly differentiated group (ten patients) and well-moderately differentiated group (eleven patients). Quantitative parameters derived from FDG-PET, diffusion-weighted imaging (DWI), and dynamic contrast enhanced-magnetic resonance imaging (DCE-MRI) were calculated based on volume of interest drawn on the tumor and compared between two groups. The efficacy of quantitative parameters for the estimation of histologic grades of HSCC was evaluated.

RESULTS

There were statistically significant differences in mean value of standard uptake value (SUV), apparent diffusion coefficient (ADC), and K^trans derived from ¹⁸F-FDG PET/MRI of HSCC between two groups (p < 0.05). There was no statistically significant difference in other quantitative parameters derived from ¹⁸F-FDG PET/MRI of HSCC between two groups. The area under the curve (AUC) of the combination of SUV_mean, ADC_mean, and K^trans in the estimation of histologic grade of HSCC was 0.936 with sensitivity of 90.0% and specificity of 81.8%.

CONCLUSION

The combination of SUV_mean, ADC_mean, and K^trans derived from ¹⁸F-FDG PET/MRI can accurately predict the histologic grade of HSCC preoperatively.

PET/MR in Head and Neck Cancer - An Update

In academic centers, PET/MR has taken the road to clinical nuclear medicine in the past 6 years since the last review on its applications in head and neck cancer patients in this journal. Meanwhile, older sequential PET + MR machines have largely vanished from clinical sites, being replaced by integrated simultaneous PET/MR scanners. Evidence from several studies suggests that PET/MR overall performs equally well as PET/CT in the staging and restaging of head and neck cancer and in radiation therapy planning. PET/MR appears to offer advantages in the characterization and prognostication of head and neck malignancies through multiparametric imaging, which demands an exact preparation and validation of imaging modalities, however. The majority of available clinical PET/MR studies today covers FDG imaging of squamous cell carcinoma arising from a broad spectrum of locations in the upper aerodigestive tract. In the future, specific PET/MR studies are desired that address specific histopathological tumor entities, nonepithelial malignancies, such as major salivary gland tumors, squamous cell carcinomas arising in specific locations, and malignancies imaged with non-FDG radiotracers. With the advent of digital PET/CT scanners, PET/MR is expected to partake in future technical developments, such as novel iterative reconstruction techniques and deviceless motion correction for respiration and gross movement in the head and neck region. Owing to the still comparably high costs of PET/MR scanners and facility requirements on the one hand, and the concentration of multidisciplinary head and neck cancer treatment mainly at academic centers on the other hand, a more widespread use of this imaging modality outside major hospitals is currently limited.