Tumor metabolism and perfusion in head and neck squamous cell carcinoma: pretreatment multimodality imaging with 1H magnetic resonance spectroscopy, dynamic contrast-enhanced MRI, and [18F]FDG-PET

Clinical utility of combined assessments of 4D volumetric perfusion CT, diffusion-weighted MRI and 18F-FDG PET-CT for the prediction of outcomes of head and neck squamous cell carcinoma treated with chemoradiotherapy

BACKGROUND

Multiparametric imaging has been seen as a route to improved prediction of chemoradiotherapy treatment outcomes. Four-dimensional volumetric perfusion CT (4D PCT) is useful for whole-organ perfusion measurement, as it reflects the heterogeneity of the tumor and its perfusion parameters. However, there has been no study using multiparametric imaging including 4D PCT for the prognostic prediction of chemoradiotherapy. The purpose of this study was to determine whether combining assessments of 4D PCT with diffusion-weighted MRI (DWI) and ¹⁸F-fluorodeoxyglucose PET-CT could enhance prognostic accuracy in head and neck squamous cell carcinoma (HNSCC) patients treated with chemoradiotherapy.

METHODS

We examined 53 patients with HNSCC who underwent 4D PCT, DWI and PET-CT before chemoradiotherapy. The imaging and clinical parameters were assessed the relations to locoregional control (LRC) and progression-free survival (PFS) by logistic regression analyses. A receiver operating characteristic (ROC) analysis was performed to assess the accuracy of the significant parameters identified by the multivariate analysis for the prediction of LRC and PFS. We additionally assessed using the scoring system whether these independent parameters could have a complementary role for the prognostic prediction.

RESULTS

The median follow-up was 30 months. In multivariate analysis, blood flow (BF; p = 0.02) and blood volume (BV; p = 0.04) were significant prognostic factors for LRC, and BF (p = 0.03) and skewness of the ADC histogram (p = 0.02) were significant prognostic factors for PFS. A significant positive correlation was found between BF and BV (ρ = 0.6, p < 0.001) and between BF and skewness (ρ = 0.46, p < 0.01). The ROC analysis showed that prognostic accuracy for LRC of BF, BV, and combination of BF and BV were 77.8%, 70%, and 92.9%, and that for PFS of BF, skewness, and combination of BF and skewness were 55.6%, 63.2%, and 77.5%, respectively. The scoring system demonstrated that the combination of higher BF and higher BV was significantly associated with better LRC (p = 0.04), and the combination of lower BF and lower skewness was significantly associated with worse PFS (p = 0.004).

CONCLUSION

A combination of parameters derived from 4DPCT and ADC histograms may enhance prognostic accuracy in HNSCC patients treated with chemoradiotherapy.

Associations between dynamic-contrast enhanced MRI and tumor infiltrating lymphocytes and tumor-stroma ratio in head and neck squamous cell cancer

Objectives

The present study used dynamic-contrast enhanced MRI (DCE-MRI) to elucidate possible associations with tumor-infiltrating lymphocytes (TIL), stroma ratio and vimentin expression in head and neck squamous cell cancer (HNSCC).

Methods

Overall, 26 patients with primary HNSCC of different localizations were involved in the study. DCE-MRI was obtained on a 3 T MRI and analyzed with a whole lesion measurement using a histogram approach. TIL- and vimentin-expression was calculated on bioptic samples before any form of treatment. P16 staining was used to define HPV-status.

Results

Tumor-stroma ratio correlated with entropy derived from K^trans (r = − 0.52, p = 0.0071) and with kurtosis derived from V_e (r = − 0.53, p = 0.0058).

Several V_e derived parameters correlated with expression of TIL within the stroma compartment. TIL within the tumor compartment correlated with entropy derived from K^trans (r = 0.39, p = 0.047), p90 derived from V_e (r = 0.41, p = 0.036) and skewness derived from V_e (r = 0.41, p = 0.037). Furthermore, these associations were different between HPV positive and negative tumors.

Conclusions

DCE-MRI might be able to reflect tumor compartments and TIL expression in HNSCC. The most promising parameters were values derived from K^trans and V_e.

Multiparametric MRI Evaluation of Oropharyngeal Squamous Cell Carcinoma. A Mono-Institutional Study

The aim of this paper is to define the pre-treatment radiological characteristics of oropharyngeal squamous cell carcinoma (OPSCC) using morphological and non-morphological magnetic resonance imaging (MRI), based on HPV status, in a single-institution cohort. In total, 100 patients affected by OPSCC were prospectively enrolled in the present study. All patients underwent 1.5T MR with standard sequences, including diffusion-weighted imaging with and intravoxel incoherent motion (IVIM-DWI) technique and a dynamic contrast-enhanced (DCE) MRI. For all patients, human papillomavirus (HPV) status was available. No statistically significant differences in the volume of primary tumors (PTs) and lymph nodes (LNs) were observed based on HPV status. When comparing the two patient groups, no significant differences were found for the PT radiologic characteristics (presence of well-defined borders, exophytic growth, ulceration, and necrosis) and LN morphology (solid/cystic/necrotic). Tumor subsite, smoking status, and alcohol intake significantly differed based on HPV status, as well as ADC and D_t values of both PTs and LNs. We detected no significant difference in DCE-MRI parameters by HPV status. Based on a multivariate logistic regression model, the combination of clinical factors, such as tumor subsite and alcohol habits, with the perfusion-free diffusion coefficient D_t of LNs, may help to accurately discriminate OPSCC by HPV status.

Multi-parametric MRI (mpMRI) for treatment response assessment of radiation therapy

Magnetic resonance imaging (MRI) plays an important role in the modern radiation therapy (RT) workflow. In comparison with computed tomography (CT) imaging, which is the dominant imaging modality in RT, MRI possesses excellent soft-tissue contrast for radiographic evaluation. Based on quantitative models, MRI can be used to assess tissue functional and physiological information. With the developments of scanner design, acquisition strategy, advanced data analysis, and modeling, multiparametric MRI (mpMRI), a combination of morphologic and functional imaging modalities, has been increasingly adopted for disease detection, localization, and characterization. Integration of mpMRI techniques into RT enriches the opportunities to individualize RT. In particular, RT response assessment using mpMRI allows for accurate characterization of both tissue anatomical and biochemical changes to support decision-making in monotherapy of radiation treatment and/or systematic cancer management. In recent years, accumulating evidence have, indeed, demonstrated the potentials of mpMRI in RT response assessment regarding patient stratification, trial benchmarking, early treatment intervention, and outcome modeling. Clinical application of mpMRI for treatment response assessment in routine radiation oncology workflow, however, is more complex than implementing an additional imaging protocol; mpMRI requires additional focus on optimal study design, practice standardization, and unified statistical reporting strategy to realize its full potential in the context of RT. In this article, the mpMRI theories, including image mechanism, protocol design, and data analysis, will be reviewed with a focus on the radiation oncology field. Representative works will be discussed to demonstrate how mpMRI can be used for RT response assessment. Additionally, issues and limits of current works, as well as challenges and potential future research directions, will also be discussed.

MRI Dynamic Contrast Imaging of Oral Cavity and Oropharyngeal Tumors

ABSTRACT

In the past decade, dynamic contrast-enhanced magnetic resonance imaging has had an increasing role in assessing the microvascular characteristics of various tumors, including head and neck cancer. Dynamic contrast-enhanced magnetic resonance imaging allows noninvasive assessment of permeability and blood flow, both important parametric features of tumor hypoxia, which is in turn a marker for treatment resistance for head and neck cancer.In this article we will provide a comprehensive review technique in evaluating tumor proliferation and application of its parameters in differentiating between various tumor types of the oral cavity and how its parameters can correlate between epidermal growth factor receptor and human papillomavirus which can have an implication in patient's overall survival rates.We will also review how the parameters of this method can predict local tumor control after treatment and compare its efficacy with other imaging modalities. Lastly, we will review how its parameters can be used prospectively to identify early complications from treatment.

Best Practices: Application of NI-RADS for Posttreatment Surveillance Imaging of Head and Neck Cancer

Imaging surveillance is an important component of posttreatment management of head and neck cancers. There is variability in the surveillance regimen used by various practitioners and institutions, with no official National Comprehensive Cancer Network guidelines for patients showing no symptoms beyond 6 months posttreatment. Moreover, imaging of the neck after treatment is a complex examination with significant interreader heterogeneity, particularly in terms of the manner in which degree of suspicion for disease recurrence is expressed. The Neck Imaging Reporting and Data System (NI-RADS) was introduced by the American College of Radiology (ACR) in 2018 as a practical guide for the interpreting radiologist. NI-RADS is a proposed interpretive framework that can be applied to any standardized or institutional surveillance imaging protocol. NI-RADS simplifies communication between radiologists and referring clinicians and provides management guidance linked to specific levels of suspicion. The ACR NI-RADS Committee also provided general best practice recommendations for imaging surveillance modality and timing in the 2018 white paper. This article will review existing literature regarding choice of modality and timeline for surveillance in treated cancer of the head and neck. NI-RADS will then be presented as an approach to imaging reporting, interpretation, and design of next steps in management.

Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) for pretreatment prediction of neoadjuvant chemotherapy response in locally advanced hypopharyngeal cancer

Objective:The aim of this study was to predict response to neoadjuvant chemotherapy (NAC) in patients with locally advanced hypopharyngeal cancer by dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI).Methods:A retrospective study enrolled 46 diagnosed locally advanced hypopharyngeal cancer. DCE-MRI were performed prior to and after two cycles of NAC. The volume transfer constant (K^trans), extracellular extravascular volume fraction (V_e), and plasma volume fraction (K_ep) were computed from primary tumors. DCE-MRI parameters were used to measure tumor response according to the Response Evaluation Criteria in Solid Tumors criteria (RECIST).Results：After 2 NAC cycles, 30 out of 46 patients were categorized into the responder group, whereas the other 16 were categorized into non-responder group. Compared with the pretreatment value, the post-treatment K^trans and K_ep was significantly lower (P < 0.05), but no significant change in V_e (P > 0.05). Compared with non-responders, a notably higher pretreatment K^trans, K_ep, lower post-treatment K^trans, higher ΔK^trans and ΔK_ep were observed in responders (all P < 0.05). While the pretreatment V_e, post-treatment V_e, and ΔV_e did not differ significantly (P>0.05) between the two groups. The receiver operating characteristic curve analysis revealed that pretreatment K^trans of 0.202/min is the most optimal cut-off in predicting response to chemotherapy, resulting in an AUC of 0.837 and corresponding sensitivity and specificity of 76.7%, and 81.1%, respectively.Conclusion:DCE-MRI especially pretreatment K^trans can potentially predict the treatment response to neoadjuvant chemotherapy for hypopharyngeal cancer.Advances in knowledge:Few studies of DCE-MRI on hypopharyngeal cancer treated with chemoradiation reported. The results demonstrate that DCE-MRI especially pretreatment K^trans may be more potential value in predicting the treatment response to neoadjuvant chemotherapy for hypopharyngeal cancer.

Functional Imaging to Predict Treatment Response in Head and Neck Cancer: How Close are We to Biologically Adaptive Radiotherapy?

It is increasingly recognised that head and neck cancer represents a spectrum of disease with a differential response to standard treatments. Although prognostic factors are well established, they do not reliably predict response. The ability to predict response early during radiotherapy would allow adaptation of treatment: intensifying treatment for those not responding adequately or de-intensifying remaining therapy for those likely to achieve a complete response. Functional imaging offers such an opportunity. Changes in parameters obtained with functional magnetic resonance imaging or positron emission tomography-computed tomography during treatment have been found to be predictive of disease control in head and neck cancer. Although many questions remain unanswered regarding the optimal implementation of these techniques, current, maturing and future studies may provide the much-needed homogeneous cohorts with larger sample sizes and external validation of parameters. With a stepwise and collaborative approach, we may be able to develop imaging biomarkers that allow us to deliver personalised, biologically adaptive radiotherapy for head and neck cancer.

Quantitative dynamic contrast-enhanced MR imaging can be used to predict the pathologic stages of oral tongue squamous cell carcinoma

Background

To investigate whether quantitative dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) pharmacokinetic parameters can be used to predict the pathologic stages of oral tongue squamous cell carcinoma (OTSCC).

Methods

For this prospective study, DCE-MRI was performed in participants with OTSCC from May 2016 to June 2017. The pharmacokinetic parameters, including K^trans, K_ep, V_e, and V_p, were derived from DCE-MRI by utilizing a two-compartment extended Tofts model and a three-dimensional volume of interest. The postoperative pathologic stage was determined in each patient based on the 8th AJCC cancer staging manual. The quantitative DCE-MRI parameters were compared between stage I–II and stage III–IV lesions. Logistic regression analysis was used to determine independent predictors of tumor stages, followed by receiver operating characteristic (ROC) analysis to evaluate the predictive performance.

Results

The mean K^trans, K_ep and V_p values were significantly lower in stage III–IV lesions compared with stage I–II lesions (p = 0.013, 0.005 and 0.011, respectively). K_ep was an independent predictor for the advanced stages as determined by univariate and multivariate logistic analysis. ROC analysis showed that K_ep had the highest predictive capability, with a sensitivity of 64.3%, a specificity of 82.6%, a positive predictive value of 81.8%, a negative predictive value of 65.5%, and an accuracy of 72.5%.

Conclusion

The quantitative DCE-MRI parameter K_ep can be used as a biomarker for predicting pathologic stages of OTSCC.

Patient-Centric Head and Neck Cancer Radiation Therapy: Role of Advanced Imaging

The traditional 'one-size-fits-all' approach to H&N cancer therapy is archaic. Advanced imaging can identify radioresistant areas by using biomarkers that detect tumor hypoxia, hypercellularity etc. Highly conformal radiotherapy can target resistant areas with precision. The critical information that can be gleaned about tumor biology from these advanced imaging modalities facilitates individualized radiotherapy. The tumor imaging world is pushing its boundaries. Molecular imaging can now detect protein expression and genotypic variations across tumors that can be exploited for tailoring treatment. The exploding field of radiomics and radiogenomics extracts quantitative, biologic and genetic information and further expands the scope of personalized therapy.

Multiparametric positron emission tomography/magnetic resonance imaging in nasopharyngeal carcinoma: Correlations between magnetic resonance imaging functional parameters and 18F-fluorodeoxyglucose positron emission tomography imaging biomarkers and their predictive value for treatment failure

Objectives:

The clinical significance of positron emission tomography/magnetic resonance imaging (PET/MRI) functional parameters in nasopharyngealcarcinoma (NPC) remains unclear. The purpose of this prospective study was two-fold: (1) to investigate the associations between simultaneously acquired PET/MRI perfusion, diffusion, and glucose metabolism parameters in patients with NPC and (2) to analyze their predictive value with respect to treatment failure.

Materials and Methods:

We enrolled 85 patients with primary NPC who simultaneously underwent¹⁸F-fluorodeoxyglucose PET/CT and PET/MRI before definitive treatment. The following variables were determined: (1) functional parameters from the MRI component, including perfusion values (K^trans,k_ep,v_e, and initial area under the enhancement curve) and apparent diffusion coefficient (ADC) values, and (2) PET parameters, including metabolic tumor volume (MTV). The reciprocal interrelationships between these parameters and their correlations with treatment failure were examined.

Results:

We observed significant negative associations between K^trans and ADC (r = −0.215, P = 0.049) as well as between v_e and ADC (r = −0.22, P = 0.04). Correlations between PET and MRI functional parameters were not statistically significant. Treatment failures were observed in 21.2% of patients without distant metastases. Multivariate analysis identified v_e as a significant independent predictor for treatment failure (P = 0.022), whereas MTV showed a borderline significance (P = 0.095). Patients in whom both v_e and MTV values were increased had a significantly higher rate of treatment failure (62.5%) than those with either one (21.9%) or no (7.7%) increased parameter (P = 0.004).

Conclusion:

Correlation analyses revealed complex interrelationships among PET and MRI indices measured in patients with NPC. These parameters may have a complementary role in predicting treatment failure in this clinical setting.

Correlation between histogram-based DCE-MRI parameters and 18F-FDG PET values in oropharyngeal squamous cell carcinoma: Evaluation in primary tumors and metastatic nodes

OBJECTIVES

To investigate the correlation between histogram-based Dynamic Contrast-Enhanced magnetic resonance imaging (DCE-MRI) parameters and positron emission tomography with 18F-fluorodeoxyglucose (18F-FDG-PET) values in oropharyngeal squamous cell carcinoma (OPSCC), both in primary tumors (PTs) and in metastatic lymph nodes (LNs).

METHODS

52 patients with a new pathologically-confirmed OPSCC were included in the present retrospective cohort study. Imaging including DCE-MRI and 18F-FDG PET/CT scans were acquired in all patients. Both PTs and the largest LN, if present, were volumetrically contoured. Quantitative parameters, including the transfer constants, Ktrans and Kep, and the volume of extravascular extracellular space, ve, were calculated from DCE-MRI. The percentiles (P), P10, P25, P50, P75, P90, and skewness, kurtosis and entropy were obtained from the histogram-based analysis of each perfusion parameter. Standardized uptake values (SUV), SUVmax, SUVpeak, SUVmean, metabolic tumor volume (MTV) and total lesion glycolysis (TLG) were calculated applying a SUV threshold of 40%. The correlations between all variables were investigated with the Spearman-rank correlation test. To exclude false positive results under multiple testing, the Benjamini-Hockberg procedure was applied.

RESULTS

No significant correlations were found between any parameters in PTs, while significant associations emerged between Ktrans and 18F-FDG PET parameters in LNs.

CONCLUSIONS

Evident relationships emerged between DCE-MRI and 18F-FDG PET parameters in OPSCC LNs, while no association was found in PTs. The complex relationships between perfusion and metabolic biomarkers should be interpreted separately for primary tumors and lymph-nodes. A multiparametric approach to analyze PTs and LNs before treatment is advisable in head and neck squamous cell carcinoma (HNSCC).

Associations between FDG-PET and Ki 67-index in head and neck cancer: A meta-analysis

BACKGROUND

FDG-PET might be able to reflect histopathology features of tumors. Ki 67 in head and neck carcinomas (HNSCC). The present study sought to elucidate the association between Ki 67 index and SUVmax based upon a large patient sample.

METHODS

PubMed database was screened for studies analyzed the relationship between Ki 67 and SUV in HNSCC. Nine studies comprising 211 patients were suitable for analysis.

RESULTS

SUVmax increased with tumor grade and was statistically significant different between G1, G2, and G3 tumors. The ROC analysis for discrimination between G1/G2 and G3 tumors revealed an area under curve of 0.71. In the overall patient sample, SUVmax correlated statistically significant with Ki 67 index (r = 0.154, P = .032).

CONCLUSION

The present study identified a weak correlation between SUV values and proliferation index Ki 67 index in HNSCC in a large patient sample. Therefore, SUVmax cannot be used as surrogate parameter for proliferation activity in HNSCC.

Role of intravoxel incoherent motion parameters in gastroesophageal cancer: relationship with 18F-FDG-positron emission tomography, computed tomography perfusion and magnetic resonance perfusion imaging parameters

BACKGROUND

Identification of pretherapeutic predictive markers in gastro-esophageal cancer is essential for individual-oriented treatment. This study evaluated the relationship of multimodality parameters derived from intravoxel incoherent motion method (IVIM), 18F-FDG-positron emission tomography (PET), computed tomography (CT) perfusion and dynamic contrast enhanced magnetic resonance imaging (MRI) in patients with gastro-esophageal cancer and investigated their histopathological correlation.

METHODS

Thirty-one consecutive patients (28 males; median age 63.9 years; range 37-84 years) with gastro-esophageal adenocarcinoma (N.=22) and esophageal squamous cell carcinoma (N.=9) were analyzed. IVIM parameters: pseudodiffusion (D*), perfusion fraction (fp), true diffusion (D) and the threshold b-value (bval); PET-parameters: SUV<inf>max</inf>, metabolic tumor volume (MTV) and total lesion glycolysis (TLG); CT perfusion parameters: blood flow (BF), blood volume (BV) and mean transit time (MTT); and MR perfusion parameters: time to enhance, positive enhancement integral, time-to-peak (TTP), maximum-slope-of-increase, and maximum-slope-of-decrease were determined, and correlated to each other and to histopathology.

RESULTS

IVIM and PET parameters showed significant negative correlations: MTV and bval (r<inf>s</inf> =-0.643, P=0.002), TLG and bval (r<inf>s</inf>=-0.699, P<0.01) and TLG and fp (r<inf>s</inf>=-0.577, P=0.006). Positive correlation was found for TLG and D (r<inf>s</inf>=0.705, P=0.000). Negative correlation was found for bval and staging (r<inf>s</inf>=0.590, P=0.005). Positive correlation was found for positive enhancement interval and BV (r<inf>s</inf>=0.547, P=0.007), BF and regression index (r<inf>s</inf>=0.753, P=0.005) and for time-to-peak and staging (r<inf>s</inf>=0.557, P=0.005).

CONCLUSIONS

IVIM parameters (bval, fp, D) provide quantitative information and correlate with PET parameters (MTV, TLG) and staging. IVIM might be a useful tool for additional characterization of gastro-esophageal cancer.

Evaluation of intratumoral heterogeneity by using diffusion kurtosis imaging and stretched exponential diffusion-weighted imaging in an orthotopic hepatocellular carcinoma xenograft model

Background

To investigate the value of diffusion kurtosis imaging (DKI) and diffusion-weighted imaging (DWI) with a stretched exponential model (SEM) in the evaluation of tumor heterogeneity in an orthotopic hepatocellular carcinoma (HCC) xenograft model.

Methods

Thirty orthotopic HCC xenograft nude mice models were established and randomly divided into two groups, the sorafenib induction group (n=15) and control group (n=15). Every mouse in each group underwent MRI with DKI and SEM on a 1.5T MR scanner at 7, 14, and 21 days after sorafenib intervention. DKI and SEM parameters including mean kurtosis (MK), mean diffusivity (MD), α, and distributed diffusion coefficient (DDC) were measured, calculated, and compared between the two groups and among different time points. Sequential correlations between histopathological results including necrotic fraction (NF), micro-vessel density (MVD), Ki-67 index, standard deviation (SD), and kurtosis from hematoxylin-eosin staining, and DKI and SEM parameters were analyzed.

Results

MK, MD, and DDC of HCC in the sorafenib induction group were significantly higher than those in the control group at each time point (P<0.05), while α was significantly lower (P<0.05). Significantly positive correlations were found between MK and NF (r=0.693, P=0.010), SD (r =0.785, P=0.003), kurtosis (r=0.779, P=0.003), between MD and NF (r=0.794, P=0.003), SD (r=0.629, P=0.020), kurtosis (r=0.645, P=0.018), and between DDC and NF (r=0.800, P=0.003), SD (r=0.636, P=0.020), kurtosis (r=0.664, P=0.016), and significantly negative correlations were observed between α and NF (r=-0.704, P=0.009), SD (r=-0.754, P=0.003), and kurtosis (r=-0.792, P=0.003) in the sorafenib induction group.

Conclusions

DKI and SEM parameters may be potentially useful for evaluating intratumoral heterogeneity in HCC.

Quantitative parameters correlated well with differentiation of squamous cell carcinoma at head and neck: a study of dynamic contrast-enhanced MRI

Background

Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) is widely used for the diagnosis and prognostic assessment of head and neck squamous cell carcinoma (HNSCC). However, no research on grading HNSCC using DCE-MRI has been found. We hypothesize that DCE-MRI can grade the HNSCC non-invasively.

Purpose

To verify the hypothesis that DCE-MRI can grade the HNSCC non-invasively.

Material and Methods

Forty-two patients with histopathologically proved HNSCC from September 2013 to February 2016 were retrospectively analyzed. Chi-square test was used to compare patterns of time intensity curves (TICs) between well and poorly differentiated HNSCC. Two-sample t-test was performed to calculate the difference of volume transfer constant (Ktrans), extravascular extracellular volume fraction (Ve), and initial area under the curve (iAUC) between groups. The diagnostic ability and cut-off value were assessed by receiver operator characteristic analysis.

Results

Most TICs of HNSCC are type III; no difference between well and poorly differentiated HNSCC has been found ( P > 0.05). The value of Ktrans, Ve, and iAUC for well and poorly differentiated HNSCC are (0.218 ± 0.048; 0.383 ± 0.074) min−1, (0.605 ± 0.108; 0.712 ± 0.150), and (27.552 ± 6.238; 43.157 ± 9.148), respectively. Ktrans, Ve, and iAUC are higher in poorly differentiated HNSCC, compared with well differentiated HNSCC ( P < 0.001, 0.013, and < 0.001, respectively). Ktrans has the greatest diagnostic significance with Youden’s index being 0.859 by cut-off value 0.270 min−1. The diagnostic sensitivity and specificity were 95.0% and 90.9%, respectively.

Conclusion

The Ktrans, Ve, and iAUC of HNSCC can be reliable quantitative parameters for evaluating well and poorly differentiated HNSCC where Ktrans has the highest value.

Quantitative imaging biomarkers alliance (QIBA) recommendations for improved precision of DWI and DCE-MRI derived biomarkers in multicenter oncology trials

Physiological properties of tumors can be measured both in vivo and noninvasively by diffusion-weighted imaging and dynamic contrast-enhanced magnetic resonance imaging. Although these techniques have been used for more than two decades to study tumor diffusion, perfusion, and/or permeability, the methods and studies on how to reduce measurement error and bias in the derived imaging metrics is still lacking in the literature. This is of paramount importance because the objective is to translate these quantitative imaging biomarkers (QIBs) into clinical trials, and ultimately in clinical practice. Standardization of the image acquisition using appropriate phantoms is the first step from a technical performance standpoint. The next step is to assess whether the imaging metrics have clinical value and meet the requirements for being a QIB as defined by the Radiological Society of North America's Quantitative Imaging Biomarkers Alliance (QIBA). The goal and mission of QIBA and the National Cancer Institute Quantitative Imaging Network (QIN) initiatives are to provide technical performance standards (QIBA profiles) and QIN tools for producing reliable QIBs for use in the clinical imaging community. Some of QIBA's development of quantitative diffusion-weighted imaging and dynamic contrast-enhanced QIB profiles has been hampered by the lack of literature for repeatability and reproducibility of the derived QIBs. The available research on this topic is scant and is not in sync with improvements or upgrades in MRI technology over the years. This review focuses on the need for QIBs in oncology applications and emphasizes the importance of the assessment of their reproducibility and repeatability. Level of Evidence: 5 Technical Efficacy Stage: 1 J. Magn. Reson. Imaging 2019;49:e101-e121.

Dynamic contrast-enhanced magnetic resonance imaging for differentiating osteomyelitis from acute neuropathic arthropathy in the complicated diabetic foot

OBJECTIVE

The main purpose of this study was to investigate the diagnostic value of dynamic contrast-enhanced MRI (DCE-MRI) in differentiating osteomyelitis from acute neuropathic arthropathy in the diabetic foot.

MATERIALS AND METHODS

This prospective study was carried out on 30 diabetic foot patients, with a mean age of 51 years. The patients all underwent clinical examinations, laboratory examinations and DCE-MRI. The DCE-MRI parameters (K^trans, K_ep and V_e) of the regions of acute neuropathic arthropathy and osteomyelitis were calculated. Receiver operating characteristic curves (ROCs) were used to identify the DCE-MRI parameters that showed the highest accuracy in differentiating the acute neuropathic arthropathy from the osteomyelitic regions. Pearson correlation coefficients were used to assess the correlations among the DCE-MRI parameters, the level of C-reactive protein (CRP) and the erythrocyte sedimentation rate (ESR).

RESULTS

The K^trans, K_ep and V_e values of the osteomyelitic regions were higher than those of the acute neuropathic arthropathy regions, and significant differences were found between the two groups (P = 0.000, P = 0.000, P = 0.000). The ROC analysis showed that K^trans and V_e performed best in differentiating osteomyelitis from acute neuropathic arthropathy, both with an area under the curve of 0.938. The Pearson correlation coefficients showed that the DCE-MRI parameters correlated significantly with the level of CRP and ESR (P = 0.000, P = 0.014, P = 0.000; P = 0.000, P = 0.000, P = 0.013).

CONCLUSIONS

Our results showed that DCE-MRI may provide reproducible parameters that can reliably differentiate osteomyelitis from acute neuropathic arthropathy.

Evaluating Imaging Biomarkers of Acquired Resistance to Targeted EGFR Therapy in Xenograft Models of Human Head and Neck Squamous Cell Carcinoma

Background: Overexpression of EGFR is a negative prognostic factor in head and neck squamous cell carcinoma (HNSCC). Patients with HNSCC who respond to EGFR-targeted tyrosine kinase inhibitors (TKIs) eventually develop acquired resistance. Strategies to identify HNSCC patients likely to benefit from EGFR-targeted therapies, together with biomarkers of treatment response, would have clinical value. Methods: Functional MRI and 18F-FDG PET were used to visualize and quantify imaging biomarkers associated with drug response within size-matched EGFR TKI-resistant CAL 27 (CALR) and sensitive (CALS) HNSCC xenografts in vivo, and pathological correlates sought. Results: Intrinsic susceptibility, oxygen-enhanced and dynamic contrast-enhanced MRI revealed significantly slower baseline R 2 ∗ , lower hyperoxia-induced Δ R 2 ∗ and volume transfer constant Ktrans in the CALR tumors which were associated with significantly lower Hoechst 33342 uptake and greater pimonidazole-adduct formation. There was no difference in oxygen-induced ΔR1 or water diffusivity between the CALR and CALS xenografts. PET revealed significantly higher relative uptake of 18F-FDG in the CALR cohort, which was associated with significantly greater Glut-1 expression. Conclusions: CALR xenografts established from HNSCC cells resistant to EGFR TKIs are more hypoxic, poorly perfused and glycolytic than sensitive CALS tumors. MRI combined with PET can be used to non-invasively assess HNSCC response/resistance to EGFR inhibition.

Dynamic Contrast-enhanced Magnetic Resonance Imaging for Differentiating Between Primary Tumor, Metastatic Node and Normal Tissue in Head and Neck Cancer

OBJECTIVE

To study the difference of the Dynamic Contrast-Enhanced Magnetic Resonance Imaging (DCE-MRI) parameters among the primary tumor, metastatic node and peripheral normal tissue of head and neck cancer.

MATERIALS AND METHODS

Consecutive newly-diagnosed head and neck cancer patients with nodal metastasis between December 2010 and July 2013 were recruited, and 25 patients (8 females; 24~63,mean 43±11 years old) were enrolled. DCE-MRI was performed in the primary tumor region including the regional lymph nodes on a 3.0-T MRI system. Three quantitative parameters: Ktrans (volume transfer constant), ve (volume fraction of extravascular extracellular space) and kep (the rate constant of contrast transfer) were calculated for the largest node. A repeated-measure ANOVA with a Greenhouse-Geisser correction and post hoc tests using the Bonferroni correction were used to evaluate the differences in Ktrans, ve and kep among primary tumors, metastatic nodes and normal tissue.

RESULTS

The values of both Ktrans and ve of normal tissue differed significantly from those of nodes (both P < 0.001) and primary tumors (both P < 0.001) respectively, while no significant differences of Ktrans and ve were observed between nodes and primary tumors (P = 0.075 and 0.365 respectively). The kep values of primary tumors were significantly different from those of nodes (P = 0.001) and normal tissue (P = 0.002), while no significant differences between nodes and normal tissue (P > 0.999).

CONCLUSION

The DCE-MRI parameters were different in the tumors, metastatic nodes and normal tissue in head and neck cancer. These findings may be useful in the characterization of head and neck cancer.

Dynamic contrast-enhanced magnetic resonance imaging for pretreatment prediction of early chemo-radiotherapy response in larynx and hypopharynx carcinoma

Purpose

This study is to investigate the use of dynamic contrast-enhanced magnetic resonance imaging in predicting early response to CRT (chemo-radiotherapy) in patients with larynx and hypopharynx carcinoma from primary tumors.

Method

Sixty-two patients with larynx and hypopharynx carcinoma underwent two DCE-MRI studies: a baseline exam before any treatmentanda post-treatment exam 3 weeks after CRT. At the end of treatment, patients were classified as responders, or non-responders according to the Response Evaluation Criteria in Solid Tumors criteria (RECIST). The time intensity curves (TIC) were extracted and processed to obtain time to peak (TTP), maximum slope of increase (MSI), maximum slope of decrease (MSD) and positive enhancement integral (PEI), and the semi-quantitative MRI parameters were compared and analyzed between the two groups.

Results

Fifty-four and 8 patients were included the responder and non-responder groups. It was observed that the MSI, MSD, and PEI were significantly lower post-treatment than pre-treatment(P < 0.05). The pretreatment MSI, MSD, and PEI parameters of responders were significantly higher than those of non-responders (P< 0.05). The post-treatment MSI, MSD, and PEI parameters of responders were significantly lower than those of non-responders (P< 0.05). Based on ROC curve analysis, at a threshold of 154.81 for pretreatment MSI, the corresponding AUC, sensitivity, and specificity were 0.882, 89.3% and 73.5%, respectively.

Conclusion

The semi-quantitative DCE-MRI may aid in the prediction of early response to CRT in patients with larynx and hypopharynx carcinoma.

Adaptive Boost Target Definition in High-Risk Head and Neck Cancer Based on Multi-imaging Risk Biomarkers

PURPOSE

Positron emission tomography with ¹⁸F-deoxyglucose (FDG), dynamic contrast-enhanced magnetic resonance imaging (MRI), and diffusion-weighted MRI each identify unique risk factors for treatment outcomes in head and neck cancer (HNC). Clinical trials in HNC largely rely on a single imaging modality to define targets for boosting. This study aimed to investigate the spatial correspondence of FDG uptake, perfusion, and the apparent diffusion coefficient (ADC) in HNC and their response to chemoradiation therapy (CRT) and to determine the implications of this overlap or lack thereof for adaptive boosting.

METHODS AND MATERIALS

Forty patients with HNC enrolled in a clinical trial underwent FDG positron emission tomography-computed tomography before CRT and underwent dynamic contrast-enhanced and diffusion-weighted MRI scans before and during CRT. The gross tumor volume (GTV) of the primary tumor was contoured on post-gadolinium T1-weighted images. Tumor subvolumes with high FDG uptake, low blood volume (BV), and low ADC were created by using previously established thresholds. Spatial correspondences between subvolumes were analyzed using the Dice coefficient, and those between each pair of image parameters at voxel level were analyzed by Spearman rank correlation coefficients.

RESULTS

Prior to CRT, the median subvolumes of high FDG, low BV, and low ADC relative to the primary GTV were 20%, 21%, and 45%, respectively. Spearman correlation coefficients between BV and ADC varied from -0.47 to 0.22; between BV and FDG, from -0.08 to 0.59; and between ADC and FDG, from -0.68 to 0.25. Dice coefficients between subvolumes of FDG and BV, FDG and ADC, and BV and ADC were 10%, 46%, and 15%, respectively. The union of the 3 parameters was 64% of the GTV. The union of the subvolumes of BV and ADC was 56% of the GTV before CRT but was reduced significantly by 57% after 10 fractions of radiation therapy.

CONCLUSIONS

High FDG uptake, low BV, and low ADC as imaging risk biomarkers of HNC identify largely distinct tumor characteristics. A single imaging modality may not define the boosting target adequately.

Dynamic Contrast-Enhanced MRI-Derived Intracellular Water Lifetime (τ i ): A Prognostic Marker for Patients with Head and Neck Squamous Cell Carcinomas

BACKGROUND AND PURPOSE

Shutter-speed model analysis of dynamic contrast-enhanced MR imaging allows estimation of mean intracellular water molecule lifetime (a measure of cellular energy metabolism) and volume transfer constant (a measure of hemodynamics). The purpose of this study was to investigate the prognostic utility of pretreatment mean intracellular water molecule lifetime and volume transfer constant in predicting overall survival in patients with squamous cell carcinomas of the head and neck and to stratify p16-positive patients based upon survival outcome.

MATERIALS AND METHODS

A cohort of 60 patients underwent dynamic contrast-enhanced MR imaging before treatment. Median, mean intracellular water molecule lifetime and volume transfer constant values from metastatic nodes were computed from each patient. Kaplan-Meier analyses were performed to associate mean intracellular water molecule lifetime and volume transfer constant and their combination with overall survival for the first 2 years, 5 years, and beyond (median duration, >7 years).

RESULTS

By the last date of observation, 18 patients had died, and median follow-up for surviving patients (n = 42) was 8.32 years. Patients with high mean intracellular water molecule lifetime (4 deaths) had significantly (P = .01) prolonged overall survival by 5 years compared with those with low mean intracellular water molecule lifetime (13 deaths). Similarly, patients with high mean intracellular water molecule lifetime (4 deaths) had significantly (P = .006) longer overall survival at long-term duration than those with low mean intracellular water molecule lifetime (14 deaths). However, volume transfer constant was a significant predictor for only the 5-year follow-up period. There was some evidence (P < .10) to suggest that mean intracellular water molecule lifetime and volume transfer constant were associated with overall survival for the first 2 years. Patients with high mean intracellular water molecule lifetime and high volume transfer constant were associated with significantly (P < .01) longer overall survival compared with other groups for all follow-up periods. In addition, p16-positive patients with high mean intracellular water molecule lifetime and high volume transfer constant demonstrated a trend toward the longest overall survival.

CONCLUSIONS

A combined analysis of mean intracellular water molecule lifetime and volume transfer constant provided the best model to predict overall survival in patients with squamous cell carcinomas of the head and neck.

CT Texture Analysis Potentially Predicts Local Failure in Head and Neck Squamous Cell Carcinoma Treated with Chemoradiotherapy

BACKGROUND AND PURPOSE

The accurate prediction of prognosis and failure is crucial for optimizing treatment strategies for patients with cancer. The purpose of this study was to assess the performance of pretreatment CT texture analysis for the prediction of treatment failure in primary head and neck squamous cell carcinoma treated with chemoradiotherapy.

MATERIALS AND METHODS

This retrospective study included 62 patients diagnosed with primary head and neck squamous cell carcinoma who underwent contrast-enhanced CT examinations for staging, followed by chemoradiotherapy. CT texture features of the whole primary tumor were measured using an in-house developed Matlab-based texture analysis program. Histogram, gray-level co-occurrence matrix, gray-level run-length, gray-level gradient matrix, and Laws features were used for texture feature extraction. Receiver operating characteristic analysis was used to identify the optimal threshold of any significant texture parameter. We used multivariate Cox proportional hazards models to examine the association between the CT texture parameter and local failure, adjusting for age, sex, smoking, primary tumor stage, primary tumor volume, and human papillomavirus status.

RESULTS

Twenty-two patients (35.5%) developed local failure, and the remaining 40 (64.5%) showed local control. Multivariate analysis revealed that 3 histogram features (geometric mean [hazard ratio = 4.68, P = .026], harmonic mean [hazard ratio = 8.61, P = .004], and fourth moment [hazard ratio = 4.56, P = .048]) and 4 gray-level run-length features (short-run emphasis [hazard ratio = 3.75, P = .044], gray-level nonuniformity [hazard ratio = 5.72, P = .004], run-length nonuniformity [hazard ratio = 4.15, P = .043], and short-run low gray-level emphasis [hazard ratio = 5.94, P = .035]) were significant predictors of outcome after adjusting for clinical variables.

CONCLUSIONS

Independent primary tumor CT texture analysis parameters are associated with local failure in patients with head and neck squamous cell carcinoma treated with chemoradiotherapy.

Multiparametric magnetic resonance imaging in mucosal primary head and neck cancer: a prospective imaging biomarker study

BACKGROUND

Radical radiotherapy, with or without concomitant chemotherapy forms the mainstay of organ preservation approaches in mucosal primary head and neck cancer. Despite technical advances in cancer imaging and radiotherapy administration, a significant proportion of patients fail to achieve a complete response to treatment. For those patients who do achieve a complete response, acute and late toxicities remain a cause of morbidity. A critical need therefore exists for imaging biomarkers which are capable of informing patient selection for both treatment intensification and de-escalation strategies.

METHODS/DESIGN

A prospective imaging study has been initiated, aiming to recruit patients undergoing radical radiotherapy (RT) or chemoradiotherapy (CRT) for mucosal primary head and neck cancer (MPHNC). Eligible patients are imaged using FDG-PET/CT before treatment, at the end of week 3 of treatment and 12 weeks after treatment completion according to local imaging policy. Functional MRI using diffusion weighted (DWI), blood oxygen level-dependent (BOLD) and dynamic contrast enhanced (DCE) sequences is carried out prior to, during and following treatment. Information regarding treatment outcomes will be collected, as well as physician-scored and patient-reported toxicity.

DISCUSSION

The primary objective is to determine the correlation of functional MRI sequences with tumour response as determined by FDG-PET/CT and clinical findings at 12 weeks post-treatment and with local control at 12 months post-treatment. Secondary objectives include prospective correlation of functional MRI and PET imaging with disease-free survival and overall survival, defining the optimal time points for functional MRI assessment of treatment response, and determining the sensitivity and specificity of functional MRI sequences for assessment of potential residual disease following treatment. If the study is able to successfully characterise tumours based on their functional MRI scan characteristics, this would pave the way for further studies refining treatment approaches based on prognostic and predictive imaging data.

TRIAL REGISTRATION

Australian New Zealand Clinical Trials Registry (ANZCTR): ACTRN12616000534482 (26 April 2016).

Dynamic Contrast-Enhanced Magnetic Resonance Imaging of Regional Nodal Metastasis in Nasopharyngeal Carcinoma: Correlation with Nodal Staging

OBJECTIVE

To determine if the perfusion parameters by dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) of regional nodal metastasis are helpful in characterizing nodal status and to understand the relationship with those of primary tumor of nasopharyngeal carcinoma (NPC).

MATERIALS AND METHODS

Newly diagnosed patients imaged between August 2010 and January 2014 and who were found to have enlarged retropharyngeal/cervical lymph nodes suggestive of nodal disease were recruited. DCE-MRI was performed. Three quantitative parameters, Ktrans, ve, and kep, were calculated for the largest node in each patient. Kruskal-Wallis test was used to evaluate the difference in the parameters of the selected nodes of different N stages. Spearman's correlation was used to evaluate the relationship between the DCE-MRI parameters in nodes and in primary tumors.

RESULTS

Twenty-six patients (7 females; 25~67 years old) were enrolled. Ktrans was significantly different among the patients of N stages (N1, n = 3; N2, n = 17; N3, n = 6), P = 0.015. Median values (range) for N1, N2, and N3 were 0.24 min-1 (0.17~0.26 min-1), 0.29 min-1 (0.17~0.46 min-1), and 0.46 min-1 (0.29~0.70 min-1), respectively. There was no significant correlation between the parameters in nodes and primary tumors.

CONCLUSION

DCE-MRI may play a distinct role in characterizing the metastatic cervical lymph nodes of NPC.

Contemporary Diagnostic Imaging of Oral Squamous Cell Carcinoma - A Review of Literature

Oral squamous cell carcinoma (OSCC) is the most common cancer of the oral cavity and constitutes 95% of all cancers of this area. Men are affected twice as commonly as women, primarily if they are over 50 years of age. Forty percent of the lesions are localized in the tongue and 30% in the floor of the oral cavity. OSCC often affects upper and lower gingiva, buccal mucous membrane, the retromolar triangle and the palate. The prognosis is poor and the five-year survival rate ranges from 20% (OSCC in the floor of the mouth) to 60% (OSCC in the alveolar part of the mandible). Treatment is difficult, because of the localization and the invasiveness of the available methods. The diagnosis is made based on a histopathological examination of a biopsy sample.

The low detection rate of early oral SCC is a considerable clinical issue. Although the oral cavity can be easily examined, in the majority of cases oral SCC is diagnosed in its late stages. It is difficult to diagnose metastases in local lymph nodes and distant organs, which is important for planning the scope of resection and further treatment, graft implantation, and differentiation between reactive and metastatic lymph nodes as well as between disease recurrence and scars or adverse reactions after surgery or radiation therapy.

Imaging studies are performed as part of the routine work-up in oral SCC. However, it is difficult to interpret the results at the early stages of the disease. The following imaging methods are used – dental radiographs, panoramic radiographs, magnetic resonance imaging with diffusion-weighted and dynamic sequences, perfusion computed tomography, cone beam computed tomography, single-photon emission computed tomography, hybrid methods (PET/CT, PET/MRI, SPECT/CT) and ultrasound. Some important clinical problems can be resolved with the use of novel modalities such as MRI with ADC sequences and PET.

The aim of this article is to describe oral squamous cell carcinoma as it appears in different imaging methods considering both their advantages and limitations.

Multiparametric imaging using 18F-FDG PET/CT heterogeneity parameters and functional MRI techniques: prognostic significance in patients with primary advanced oropharyngeal or hypopharyngeal squamous cell carcinoma treated with chemoradiotherapy

Background

In this study, PET heterogeneity was combined with functional MRI techniques to refine the prediction of prognosis in patients with oropharyngeal or hypopharyngeal squamous cell carcinoma (OHSCC).

Methods

A total of 124 patients with primary advanced OHSCC who underwent pretreatment ¹⁸F-FDG PET/CT, dynamic contrast-enhanced MR imaging (DCE-MRI), and diffusion-weighted MR imaging (DWI) were enrolled. Conventional and heterogeneity parameters from ¹⁸F-FDG PET as well as perfusion parameters from DCE-MRI and diffusion parameter from DWI of primary tumors were analyzed in relation to recurrence-free survival (RFS) and overall survival (OS).

Results

Multivariate analysis identified hypopharyngeal tumors (P = 0.038), alcohol drinking (P = 0.006), K^trans ≤ 0.5512 (P = 0.017), and K_ep ≤ 0.8872 (P = 0.005) as adverse prognostic factors for RFS. Smoking (p = 0.009), K^trans ≤ 0.5512 (P = 0.0002), K_ep ≤ 0.8872 (P = 0.004), and the PET heterogeneity parameter uniformity ≤ 0.00381 (P = 0.028) were independent predictors of poor OS. The combination of PET uniformity with DCE-MRI parameters and smoking allowed distinguishing four prognostic groups, with 3-year OS rates of 100%, 76.6%, 57.4%, and 7.1%, respectively (P < 0.0001). This prognostic system appeared superior to both the TNM staging system (P = 0.186) and the combination of conventional PET parameters with DCE-MRI (P = 0.004).

Conclusions

Multiparametric imaging based on PET heterogeneity and DCE-MRI parameters combined with clinical risk factors is superior to the concomitant use of functional MRI coupled with conventional PET parameters. This approach may improve the prognostic stratification of OHSCC patients.

Multimodality functional imaging using DW-MRI and 18F-FDG-PET/CT during radiation therapy for human papillomavirus negative head and neck squamous cell carcinoma: Meixoeiro Hospital of Vigo Experience

AIM

To noninvasively investigate tumor cellularity measured using diffusion-weighted magnetic resonance imaging (DW-MRI) and glucose metabolism measured by ¹⁸F-labeled fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG-PET/CT) during radiation therapy (RT) for human papillomavirus negative (HPV-) head and neck squamous cell carcinoma (HNSCC).

METHODS

In this prospective study, 6 HPV- HNSCC patients underwent a total of 34 multimodality imaging examinations (DW-MRI at 1.5 T Philips MRI scanner [(n = 24) pre-, during- (2-3 wk), and post-treatment (Tx), and ¹⁸F-FDG PET/CT pre- and post-Tx (n = 10)]. All patients received RT. Monoexponential modeling of the DW-MRI data yielded the imaging metric apparent diffusion coefficient (ADC) and the mean of standardized uptake value (SUV) was measured from ¹⁸F-FDG PET uptake. All patients had a clinical follow-up as the standard of care and survival status was documented at 1 year.

RESULTS

There was a strong negative correlation between the mean of pretreatment ADC (ρ = -0.67, P = 0.01) and the pretreatment ¹⁸F-FDG PET SUV. The percentage (%) change in delta (∆) ADC for primary tumors and neck nodal metastases between pre- and Wk_2-3 Tx were as follows: 75.4% and 61.6%, respectively, for the patient with no evidence of disease, 27.5% and 32.7%, respectively, for those patients who were alive with disease, and 26.9% and 7.31%, respectively, for those who were dead with disease.

CONCLUSION

These results are preliminary in nature and are indicative, and not definitive, trends rendered by the imaging metrics due to the small sample size of HPV- HNSCC patients in a Meixoeiro Hospital of Vigo Experience.

Evaluation of Head and Neck Tumors with Functional MR Imaging

Head and neck cancer is one of the most common cancers worldwide. MR imaging-based diffusion and perfusion techniques enable the noninvasive assessment of tumor biology and physiology, which supplement information obtained from standard structural scans. Diffusion and perfusion MR imaging techniques provide novel biomarkers that can aid monitoring in pretreatment, during treatment, and posttreatment stages to improve patient selection for therapeutic strategies; provide evidence for change of therapy regime; and evaluate treatment response. This review discusses pertinent aspects of the role of diffusion and perfusion MR imaging and computational analysis methods in studying head and neck cancer.

Functional magnetic resonance imaging techniques and their development for radiation therapy planning and monitoring in the head and neck cancers

Radiation therapy (RT), in particular intensity-modulated radiation therapy (IMRT), is becoming a more important nonsurgical treatment strategy in head and neck cancer (HNC). The further development of IMRT imposes more critical requirements on clinical imaging, and these requirements cannot be fully fulfilled by the existing radiotherapeutic imaging workhorse of X-ray based imaging methods. Magnetic resonance imaging (MRI) has increasingly gained more interests from radiation oncology community and holds great potential for RT applications, mainly due to its non-ionizing radiation nature and superior soft tissue image contrast. Beyond anatomical imaging, MRI provides a variety of functional imaging techniques to investigate the functionality and metabolism of living tissue. The major purpose of this paper is to give a concise and timely review of some advanced functional MRI techniques that may potentially benefit conformal, tailored and adaptive RT in the HNC. The basic principle of each functional MRI technique is briefly introduced and their use in RT of HNC is described. Limitation and future development of these functional MRI techniques for HNC radiotherapeutic applications are discussed. More rigorous studies are warranted to translate the hypotheses into credible evidences in order to establish the role of functional MRI in the clinical practice of head and neck radiation oncology.

Potential Role of PET/MRI for Imaging Metastatic Lymph Nodes in Head and Neck Cancer

OBJECTIVE

This article explores recent developments in PET and MRI, separately or combined, for assessing metastatic lymph nodes in patients with head and neck cancer.

CONCLUSION

The synergistic role of PET and MRI for imaging metastatic lymph nodes has not been fully explored. To facilitate the understanding of the areas that need further investigation, we discuss potential mechanisms and evidence reported so far, as well as future directions and challenges for continued development and clinical research.

Correlation of Choline/Creatine and Apparent Diffusion Coefficient values with the prognostic parameters of Head and Neck Squamous Cell Carcinoma

The aim of this study was to measure choline/creatine (Ch/Cr) levels through (1)H-MRS and apparent diffusion coefficient (ADC) values through diffusion-weighted MRI, and to correlate these values with the prognostic parameters of head and neck squamous cell carcinoma (HNSCC). The institutional review board approved this study and informed written consent was obtained from all study participants. A prospective study of 43 patients (31 men and 12 women; mean age, 65 years) with HNSCC was conducted. Single-voxel (1)H-MRS was performed at the tumor or metastatic cervical lymph node with point-resolved spectroscopy (PRESS) at TE = 135 ms. Diffusion-weighted MR images with b values of 0, 500 and 1000 s/mm(2) and contrast MRI of the head and neck were performed. The Ch/Cr levels and ADC values of HNSCC were calculated. The gross tumor volume (GTV) was also calculated. The degree of tumor differentiation was determined through pathological examination. The HNSCC Ch/Cr level was negatively correlated with the ADC value (r = -0.662, p = 0.001). There was a significant difference in the Ch/Cr and ADC values at different degrees of tumor differentiation (p = 0.003 and p = 0.001) and with different GTVs (p = 0.122 and p = 0.001). The following prognostic parameter categories were used: (i) poorly differentiated and undifferentiated versus well differentiated to moderately differentiated; and (ii) HNSCC with GTV < 30 cm(3) versus GTV > 30 cm(3). The cut-off values for Cho/Cr and ADC for each category were 1.83, 0.95 and 1.94, 0.99, respectively, and the areas under the curve were 0.771, 0.967 and 0.726, 0.795, respectively, for each category. We conclude that the Ch/Cr levels determined using (1)H-MRS and the ADC values are well correlated with several prognostic parameters of HNSCC.

Dynamic contrast-enhanced MRI, diffusion-weighted MRI and 18F-FDG PET/CT for the prediction of survival in oropharyngeal or hypopharyngeal squamous cell carcinoma treated with chemoradiation

OBJECTIVES

We prospectively investigated the roles of pretreatment dynamic contrast-enhanced MR imaging (DCE-MRI), diffusion-weighted MR imaging (DWI) and ¹⁸F-fluorodeoxyglucose-positron emission tomography (¹⁸F-FDG PET)/CT for predicting survival of oropharyngeal or hypopharyngeal squamous cell carcinoma (OHSCC) patients treated with chemoradiation.

METHODS

Patients with histologically proven OHSCC and neck nodal metastases scheduled for chemoradiation were eligible. Clinical variables as well as DCE-MRI-, DWI- and ¹⁸F-FDG PET/CT-derived parameters of the primary tumours and metastatic neck nodes were analysed in relation to 3-year progression-free survival (PFS) and overall survival (OS) rates.

RESULTS

Eighty-six patients were available for analysis. Multivariate analysis identified the efflux rate constant (K _ep)-tumour < 3.79 min^-1 (P = 0.001), relative volume of extracellular extravascular space (V _e)-node < 0.23 (P = 0.004) and SUV_max-tumour > 19.44 (P = 0.025) as independent risk factors for both PFS and OS. A scoring system based upon the sum of each of the three imaging parameters allowed stratification of our patients into three groups (patients with 0/1 factor, patients with 2 factors and patients with 3 factors, respectively) with distinct PFS (3-year rates = 72 %, 38 % and 0 %, P < 0.0001) and OS (3-year rates = 81 %, 46 % and 20 %, P < 0.0001).

CONCLUSIONS

K _ep-tumour, V _e-node and SUV_max-tumour were independent prognosticators for OHSCC treated with chemoradiation. Their combination helped survival stratification.

KEY POINTS

• K _ep -tumour, V _e -node and SUV _max -tumour are independent predictors of survival rates. • The combination of these three prognosticators may help stratification of survival. • MRI and FDG-PET/CT play complementary roles in prognostication of head and neck cancer.

Pretreatment Dynamic Contrast-Enhanced MRI Improves Prediction of Early Distant Metastases in Patients With Nasopharyngeal Carcinoma

The identification of early distant metastases (DM) in patients with newly diagnosed, previously untreated nasopharyngeal carcinoma (NPC) plays an important role in selecting the most appropriate treatment approach. Here, we sought to investigate the predictive value of distinct MRI parameters for the detection of early DM.Between November 2010 and June 2011, a total of 51 newly diagnosed NPC patients were included. All of the study participants were followed until December 2014 at a single institution after completion of therapy. DM was defined as early when they were detected on pretreatment FDG-PET scans or within 6 months after initial diagnosis. The following parameters were tested for their ability to predict early DM: pretreatment FDG-PET standardized uptake value (SUV), MRI-derived AJCC tumor staging, tumor volume, and dynamic contrast-enhanced (DCE) values. The DCE-derived ve was defined as the volume fraction of the extravascular, extracellular space.Compared with patients without early DM, patients with early DM had higher SUV, tumor volume, DCE mean (median) ve, ve skewness, ve kurtosis, and the largest mean ve selected among sequential slices (P < 0.05). No differences were identified when early DM were defined only according to the results of pretreatment FDG-PET. Among different quantitative DCE parameters, the mean ve had the highest area under curve (AUC, 0.765). However, the AUCs of SUV, tumor volume, mean ve, ve skewness, ve kurtosis, or the largest mean ve selected among the sequential slices did not differ significantly from one another (P = 0.82).Taken together, our results suggest that DCE-derived ve may be a useful parameter in combination with SUV and tumor volume for predicting early DM. Dynamic contrast-enhanced MRI may be complementary to FDG-PET for selecting the most appropriate treatment approach in NPC patients.

Texture analysis on parametric maps derived from dynamic contrast-enhanced magnetic resonance imaging in head and neck cancer

AIM: To investigate the merits of texture analysis on parametric maps derived from pharmacokinetic modeling with dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) as imaging biomarkers for the prediction of treatment response in patients with head and neck squamous cell carcinoma (HNSCC).

METHODS: In this retrospective study, 19 HNSCC patients underwent pre- and intra-treatment DCE-MRI scans at a 1.5T MRI scanner. All patients had chemo-radiation treatment. Pharmacokinetic modeling was performed on the acquired DCE-MRI images, generating maps of volume transfer rate (K^trans) and volume fraction of the extravascular extracellular space (v_e). Image texture analysis was then employed on maps of K^trans and v_e, generating two texture measures: Energy (E) and homogeneity.

RESULTS: No significant changes were found for the mean and standard deviation for K^trans and v_e between pre- and intra-treatment (P > 0.09). Texture analysis revealed that the imaging biomarker E of v_e was significantly higher in intra-treatment scans, relative to pretreatment scans (P < 0.04).

CONCLUSION: Chemo-radiation treatment in HNSCC significantly reduces the heterogeneity of tumors.

The Correlations Between MRI Perfusion, Diffusion Parameters, and 18F-FDG PET Metabolic Parameters in Primary Head-and-Neck Cancer: A Cross-Sectional Analysis in Single Institute

This study aimed to investigate the relationships among parameters from dynamic contrast-enhanced (DCE) MRI, diffusion-weighted MRI (DWI), and F-fluorodeoxyglucose (F-FDG) PET in patients with primary head-and-neck squamous cell carcinoma (HNSCC).A total of 34 patients with primary HNSCC underwent DCE-MRI, DWI, and F-FDG PET before treatment. The perfusion parameters (Ktrans, Ktransmax, Kep, Ve, Vp, and AUC60) from DCE-MRI and ADC (ADCmean, ADCmin) values from DWI were calculated within the manually placed ROI around the main tumor. Standardized uptake value (SUVmax, SUVmean), metabolic tumor volume (MTV), and total lesion glycolysis (TLG = SUVmean × MTV) were calculated with thresholds of 3.0 SUV. The associations between parameters were evaluated by Pearson correlation analysis.Significant correlations were identified between Ktrans and Kep (r = 0.631), Ktrans and Ve (r = 0.603), Ktrans and ADCmean (r = 0.438), Ktransmax and Kep (r = 0.667), Ktransmax and Vp (r = 0.351), Ve and AUC60 (r = 0.364), Ve and ADCmean (r = 0.590), and Ve and ADCmin (r = 0.361). ADCmin was reversely correlated with TLG (r = -0.347). Tumor volume was significantly associated with Ktransmax (r = 0.348).The demonstrated relationships among parameters from DCE, DWI, and F-FDG PET suggest complex interactions among tumor biologic characteristics. Each diagnostic technique may provide complementary information for HNSCC.

Dynamic Contrast-Enhanced MR Imaging in Head and Neck Cancer: Techniques and Clinical Applications

In the past decade, dynamic contrast-enhanced MR imaging has had an increasing role in assessing the microvascular characteristics of various tumors, including head and neck cancer. Dynamic contrast-enhanced MR imaging allows noninvasive assessment of permeability and blood flow, both important features of tumor hypoxia, which is a marker for treatment resistance for head and neck cancer. Dynamic contrast-enhanced MR imaging has the potential to identify early locoregional recurrence, differentiate metastatic lymph nodes from normal nodes, and predict tumor response to treatment and treatment monitoring in patients with head and neck cancer. Quantitative analysis is in its early stage and standardization and refinement of technique are essential. In this article, we review the techniques of dynamic contrast-enhanced MR imaging data acquisition, analytic methods, current limitations, and clinical applications in head and neck cancer.

In Vivo Correlation of Glucose Metabolism, Cell Density and Microcirculatory Parameters in Patients with Head and Neck Cancer: Initial Results Using Simultaneous PET/MRI

Objective

To demonstrate the feasibility of simultaneous acquisition of ¹⁸F-FDG-PET, diffusion-weighted imaging (DWI) and T1-weighted dynamic contrast-enhanced MRI (T1w-DCE) in an integrated simultaneous PET/MRI in patients with head and neck squamous cell cancer (HNSCC) and to investigate possible correlations between these parameters.

Methods

17 patients that had given informed consent (15 male, 2 female) with biopsy-proven HNSCC underwent simultaneous ¹⁸F-FDG-PET/MRI including DWI and T1w-DCE. SUV_max, SUV_mean, ADC_mean, ADC_min and K^trans, k_ep and v_e were measured for each tumour and correlated using Spearman’s ρ.

Results

Significant correlations were observed between SUV_mean and K^trans (ρ = 0.43; p ≤ 0.05); SUV_mean and k_ep (ρ = 0.44; p ≤ 0.05); K^trans and k_ep (ρ = 0.53; p ≤ 0.05); and between k_ep and v_e (ρ = -0.74; p ≤ 0.01). There was a trend towards statistical significance when correlating SUV_max and ADC_min (ρ = -0.35; p = 0.08); SUV_max and K^trans (ρ = 0.37; p = 0.07); SUV_max and k_ep (ρ = 0.39; p = 0.06); and ADC_mean and v_e (ρ = 0.4; p = 0.06).

Conclusion

Simultaneous ¹⁸F-FDG-PET/MRI including DWI and T1w-DCE in patients with HNSCC is feasible and allows depiction of complex interactions between glucose metabolism, microcirculatory parameters and cellular density.

Magnetic resonance spectroscopy of paragangliomas: new insights into in vivo metabolomics

Paragangliomas (PGLs) can be associated with mutations in genes of the tricarboxylic acid (TCA) cycle. Succinate dehydrogenase (SDHx) mutations are the prime examples of genetically determined TCA cycle defects with accumulation of succinate. Succinate, which acts as an oncometabolite, can be detected by ex vivo metabolomics approaches. The aim of this study was to evaluate the potential role of proton magnetic resonance (MR) spectroscopy ((1)H-MRS) for identifying SDHx-related PGLs in vivo and noninvasively. Eight patients were prospectively evaluated with single voxel (1)H-MRS. MR spectra from eight tumors (four SDHx-related PGLs, two sporadic PGLs, one cervical schwannoma, and one cervical neurofibroma) were acquired and interpreted qualitatively. Compared to other tumors, a succinate resonance peak was detected only in SDHx-related tumor patients. Spectra quality was considered good in three cases, medium in two cases, poor in two cases, and uninterpretable in the latter case. Smaller lesions had lower spectra quality compared to larger lesions. Jugular PGLs also exhibited a poorer spectra quality compared to other locations. (1)H-MRS has always been challenging in terms of its technical requisites. This is even more true for the evaluation of head and neck tumors. However, (1)H-MRS might be added to the classical MR sequences for metabolomic characterization of PGLs. In vivo detection of succinate might guide genetic testing, characterize SDHx variants of unknown significance (in the absence of available tumor sample), and even optimize a selection of appropriate therapies.