New directions in head and neck imaging

Advanced Techniques in Head and Neck Cancer Imaging: Guide to Precision Cancer Management

Precision treatment requires precision imaging. With the advent of various advanced techniques in head and neck cancer treatment, imaging has become an integral part of the multidisciplinary approach to head and neck cancer care from diagnosis to staging and also plays a vital role in response evaluation in various tumors. Conventional anatomic imaging (CT scan, MRI, ultrasound) remains basic and focuses on defining the anatomical extent of the disease and its spread. Accurate assessment of the biological behavior of tumors, including tumor cellularity, growth, and response evaluation, is evolving with recent advances in molecular, functional, and hybrid/multiplex imaging. Integration of these various advanced diagnostic imaging and nonimaging methods aids understanding of cancer pathophysiology and provides a more comprehensive evaluation in this era of precision treatment. Here we discuss the current status of various advanced imaging techniques and their applications in head and neck cancer imaging.

Diagnostic performance of dynamic volume perfusion CT for differentiation of head and neck cancer from healthy tissue and post-therapeutic changes

BACKGROUND

Post-therapeutic tissue is bradytrophic and thus has low perfusion values in PCT. In contrast, malignant tissue is expected to show higher perfusion values as cancer growth partially depends on angiogenesis.

OBJECTIVES

This prospective study investigates perfusion computed tomography (PCT) for the post-therapeutic detection of cancer in the head and neck region.

METHODS

85 patients underwent PCT for 1) initial work-up of head and neck cancer (HNC; n=22) or 2) for follow-up (n=63). Regions of interest (ROIs) were placed in confirmed tumour, a corresponding location of benign tissue, and reference tissue. Perfusion was calculated using a single input maximum slope algorithm. Statistical analysis was performed with the Mann-Whitney U-test.

RESULTS

PCT allowed significant differentiation of malignant tissue from post-therapeutic tissue after treatment for HNC (p=0.018). Significance was even greater after normalization of perfusion values (p=0.007). PCT allowed highly significant differentiation of HNC from reference tissue (p<0.001).

CONCLUSIONS

PCT provides significantly distinct perfusion values for malignant and benign as well as post-therapeutically altered tissue in the head and neck area, thus allowing differentiation of cancer from healthy tissue. Our results show that PCT in conjunction with a standard algorithm is a potentially powerful HNC diagnostic tool.

Diagnostic Accuracy and Confidence of [18F] FDG PET/MRI in comparison with PET or MRI alone in Head and Neck Cancer

The usefulness of PET/MRI in head and neck malignancy has not been fully elucidated. The purpose of our study was to evaluate the diagnostic accuracy and confidence of PET/MRI in comparison with PET or MRI alone. This study included 73 consecutive patients who underwent [18F] FDG PET/MRI in head and neck under the suspicion of malignancy. A neuroradiologist and a nuclear medicine specialist reviewed MRI and PET images, respectively and independently, followed by a consensus review of PET/MRI one month later. For 134 lesions, accuracy and confidence were compared among PET, MRI, and PET/MRI. For lesion base, PET/MRI had a sensitivity of 85.7%, a specificity of 89.1%, a PPV of 89.6%, a negative predictive value of 85.1%, and an accuracy of 87.3%. AUCs of PET/MRI per lesion (0.926) and per patient (0.934) for diagnosing malignancy were higher than PET (0.847 and 0.747, respectively) or MRI (0.836 and 0.798, respectively) alone (P < 0.05). More than 80% of the cases (111/134) showed diagnostic concordance between PET and MRI. PPV of PET/MRI was higher in malignant concordant cases (93.2%, 55/59) than in discordant cases (62.5%, 5/8) (p = 0.040). Confident scoring rate in malignant concordant cases was higher on PET/MRI (96.6%, 57/59) than on MRI (76.3%, 45/59) (p = 0.003). In conclusion, compared with PET or MRI alone, PET/MRI presents better diagnostic performance in accuracy and confidence for diagnosis of malignancy. PET/MRI is useful in patients with head and neck cancer.

Modelling tumour volume variations in head and neck cancer: contribution of magnetic resonance imaging for patients undergoing induction chemotherapy

Primary tumour volume evaluation has predictive value for estimating survival outcomes. Using volumetric data acquired by MRI in patients undergoing induction chemotherapy (IC) these outcomes were estimated before the radiotherapy course in head and neck cancer (HNC) patients. MRI performed before and after IC in 36 locally advanced HNC patients were analysed to measure primary tumour volume. The two volumes were correlated using the linear-log ratio (LLR) between the volume in the first MRI and the volume in the second. Cox's proportional hazards models (CPHM) were defined for loco-regional control (LRC), disease-free survival (DFS) and overall survival (OS). Strict evaluation of the influence of volume delineation uncertainties on prediction of final outcomes has been defined. LLR showed good predictive value for all survival outcomes in CPHM. Predictive models for LRC and DFS at 24 months showed optimal discrimination and prediction capability. Evaluation of primary tumour volume variations in HNC after IC provides an example of modelling that can be easily used even for other adaptive treatment approaches. A complete assessment of uncertainties in covariates required for running models is a prerequisite to create reliable clinically models.

Differentiating recurrent tumours from post-treatment changes in head and neck cancers: does diffusion-weighted MRI solve the eternal dilemma?

AIM

To evaluate the utility of diffusion-weighted imaging (DWI) in differentiating post-treatment changes from tumour recurrence in head and neck cancers and to establish a threshold apparent diffusion coefficient (ADC) value to differentiate the two conditions.

MATERIALS AND METHODS

This was a prospective study of 80 treated head and neck cancer patients. The patient cohort consisted of a wide spectrum of head and neck sites, including the oral cavity, oropharynx, larynx, hypopharynx, paranasal sinuses, orbits, salivary glands, and infra-temporal fossa. Qualitative analysis of the diffusion images and quantitative analysis of the corresponding ADC maps was performed and the data were correlated with histopathological findings and clinical examinations.

RESULTS

The mean ADC value of recurrent tumours in the present cohort was 0. 932±0.19×10^-3 mm²/s and the mean ADC value of lesions representing post-treatment changes was 1.394±0.32×10^-3 mm²/s. A threshold ADC value of 1.2×10^-3mm²/s used to differentiate post-treatment changes from recurrent head and neck cancers showed the highest combined sensitivity of 90.13%, specificity of 82.5%, accuracy of 86.4%, positive predictive value of 84.4%, negative predictive value of 88.9%, and mean kappa measurement of agreement of 72.8.

CONCLUSION

Combined qualitative and quantitative analysis of DWI is a useful non-invasive technique to differentiate recurrent head and neck malignancies from post-treatment changes using a threshold ADC value.

Head and neck paragangliomas: diffusion weighted and dynamic contrast enhanced magnetic resonance imaging characteristics

Background

To determine the feature values of head and neck paragangliomas on diffusion-weighted imaging (DWI) and dynamic contrast enhanced (DCE) magnetic resonance imaging (MRI).

Methods

Patients with primary head and neck paraganglioma who underwent both DWI and DCE-MRI before treatment between January 2010 and June 2013 were identified. Two radiologists assessed apparent diffusion coefficient (ADC) values on DWI and kinetic characteristics on DCE-MRI. The time intensity curves (TICs) and dynamic parameters, including peak height (PH), maximum enhancement ratio (ER_max), time to peak enhancement (T_peak) and maximum rise slope (Slope_max), were generated and evaluated.

Results

Ten patients with head and neck paraganglioma were retrospectively analyzed. On conventional MRI, the tumors demonstrated as well-circumscribed, strongly enhanced lesions. Mean ADC value of the lesions was 1.12 ± 0.15 × 10⁻³ mm²/s. The TICs demonstrated washout pattern (type-III) in all lesions. The mean PH, ER_max, T_peak and Slope_max value was 121.24 ± 63.99, 193.79 ± 67.18, 8.16 ± 3.29 and 25.42 ± 7.91, respectively.

Conclusions

Head and neck paragangliomas demonstrate distinctive DWI and DCE-MRI results than for other benign tumors which should be taken into account in further evaluation of MRI on head and neck lesions.

Volumetric CT perfusion assessment of treatment response in head and neck squamous cell carcinoma: Comparison of CT perfusion parameters before and after chemoradiation therapy

Background and purpose

World Health Organization estimated that there were 600,000 new cases of head and neck cancers and 300,000 deaths each year worldwide. Scientific modalities to predict the treatment outcomes are not available yet. We conducted this study to (1) compare CT perfusion parameters before and after chemoradiation among patients with head and neck squamous cell carcinoma and (2) to evaluate the prognostic value of each perfusion parameter in predicting the response to chemoradiation.

Materials and methods

We conducted a prospective study among all patients with head and neck squamous cell carcinoma registered for chemoradiotherapy (CRT) at Regional Cancer Research Center, Shimla, Himachal Pradesh, India during the period June 2012 through June 2013. CTp data were acquired on a 64-slice CT scanner (Light speed VCT Xte; GE Healthcare) with 14 cm z-axis coverage using Volume Helical Shuttle (VHS) feature at baseline, on completion of 40 Gy and 66 Gy of chemoradiation. We dichotomised the treatment outcome as complete response and non-response (partial responders/stable disease/progressive disease) using RECIST 1.1 criteria. We compared all perfusion parameters at baseline, 40 Gy and 66 Gy of CRT between responders and non-responders. We dichotomised the perfusion parameters as high (>median value) and low (≤median value) to analyze association between perfusion parameters and treatment outcome. We calculated the sensitivity, specificity, predictive values, and likelihood ratios for each dichotomized perfusion parameter using Wilson Score method.

Results

We followed 24 patients (23 of them men) from start of the treatment till completion of it. All had Stage III or Stage IV of the disease. Blood flow (BF) and blood volume (BV) decreased and Mean Transit Time (MTT) increased significantly (p < 0.05) at 66 Gy among responders to CRT as compared to non-responders. Patients with high BF (>106 ml/100 g/min) at baseline were five times more likely (p = 0.004) to respond to treatment as compared to those with low BF. BF was found to be 83.3% predictive of complete response. Other perfusion parameters were not significantly predictive of outcome (p > 0.05) Combination of high BF (>106 ml/100 g/min) and low (≤47 ml/100 g/min) permeability surface (PS) was 100% predictive of response to CRT irrespective of the stage of tumor.

Conclusions

High BF at baseline is the single best predictor of response to chemoradiaton. A combination of high BF and low PS was found to be 100% predictive of complete response irrespective of the stage of the tumor.

Comparing primary tumors and metastatic nodes in head and neck cancer using intravoxel incoherent motion imaging: a preliminary experience

OBJECTIVE

This study aimed to use intravoxel incoherent motion (IVIM) imaging for investigating differences between primary head and neck tumors and nodal metastases and to evaluate IVIM efficacy in predicting outcome.

METHODS

Sixteen patients with head and neck cancer underwent IVIM diffusion-weighted imaging on a 1.5-T magnetic resonance imaging scanner. The significance of parametric difference between primary tumors and metastatic nodes were tested. Probabilities of progression-free survival and overall survival were estimated using the Kaplan-Meier method.

RESULTS

In comparison with metastatic nodes, the primary tumors had significantly higher vascular volume fraction (f) (P < 0.0009) and lower diffusion coefficient (D) (P < 0.0002). Patients with lower SD for D had prolonged progression-free survival and overall survival (P < 0.05).

CONCLUSIONS

Pretreatment IVIM measures were feasible in investigating the physiologic differences between the 2 tumor tissues. After appropriate validation, these findings might be useful in optimizing treatment planning and improving patient care.

Cervical lymph node evaluation and diagnosis

This article discusses the rationale for imaging cervical lymph nodes and reviews nodal anatomy and common drainage patterns, imaging features of pathologic lymph nodes, and the advantages of various imaging modalities available for evaluation and diagnosis of the lymph nodes.

Head and neck tumors: assessment of perfusion-related parameters and diffusion coefficients based on the intravoxel incoherent motion model

BACKGROUND AND PURPOSE

IVIM MR imaging provides perfusion and diffusion information with a single diffusion-weighted MR image. We determined whether PP and D differ among various types of head and neck tumors.

MATERIALS AND METHODS

The study cohort included 123 head and neck tumors: 30 SCCs, 28 benign and 20 malignant SG tumors, 36 lymphomas, and 9 schwannomas. The D and PP values were determined by using b-values of 0, 500, and 1000 s/mm(2) based on the IVIM model.

RESULTS

The PP values (lymphomas, 0.09 ± 0.04; SCCs, 0.15 ± 0.04; and malignant SG tumors, 0.22 ± 0.07) and D values (0.47 ± 0.07 × 10(-3) mm(2)/s, 0.82 ± 0.17 × 10(-3) mm(2)/s, and 1.03 ± 0.16 × 10(-3) mm(2)/s, respectively) were significantly different among the malignant tumors (P < .01). These values were also significantly different between pleomorphic adenomas (0.13 ± 0.02 and 1.44 ± 0.39 × 10(-3) mm(2)/s) and Warthin tumors (0.19 ± 0.04 and 0.73 ± 0.22 × 10(-3) mm(2)/s) (P < .001). The PP values of malignant SG tumors were significantly different from those of pleomorphic adenomas (P = .001) and the D values of the malignant SG tumors were significantly different from those of pleomorphic adenomas (P = .002) and Warthin tumors (P = .007). Schwannomas had large PP (0.23 ± 0.08) and D values (1.26 ± 0.20 × 10(-3) mm(2)/s), greatly overlapping those of some SG tumor types.

CONCLUSIONS

Head and neck tumors had distinctive PP and D values by using IVIM MR imaging.

MR assessment of oral cavity carcinomas

Approximately half of head and neck carcinomas arise from the oral cavity. Imaging plays an essential role in the preoperative evaluation of oral cavity carcinomas. MR imaging is particularly advantageous in the evaluation of the oral cavity, with better depiction of the anatomy in this region and reduction of dental artifacts compared with CT. MR is also the preferred imaging modality for the evaluation of bone marrow invasion and perineural tumor spread, which are findings critical for treatment planning. Advanced MR imaging techniques may potentially better delineate true tumor extent, determine lymph node metastases, and predict treatment response.

Head and neck cancer: value of perfusion CT in depicting primary tumor spread

Background

The aim of this study was to assess head and neck squamous cell cancer and surrounding tissue in computed tomography contrast enhanced and perfusion studies, and to examine the role of perfusion imaging in depiction of tissue infiltration.

Material/Methods

We prospectively evaluated 43 primary malignant head and neck tumors, using standard CT followed by perfusion. Blood flow, blood volume, mean transit time, and permeability values were obtained using regions of interest (ROIs) over lesions and surrounding tissue. Results were compared with histological analysis of resected tissue. Sensitivity, specificity, accuracy, positive and negative predictive values were calculated for both methods.

Results

We found significant differences between infiltrated and non-infiltrated tissue, especially with regard to muscles. In case of bone and salivary gland infiltration, change in perfusion parameters did not allow proper diagnosis.

Conclusions

CTP shows promise in depicting malignant infiltration. The combined use of CECT plus CTP results in correct staging of the majority of head and neck tumors.

Pictorial Essay: Early- and Late-term Effects of Radiotherapy in Head and Neck Imaging

The purpose of this article is to illustrate the cross-sectional imaging appearance of postradiation changes and complications of radiotherapy in the head and neck. Radiotherapy is an important treatment modality for head and neck cancer, and is often used in conjunction with chemotherapy. Recognition of the varied effects of radiotherapy to the head and neck region is essential to correctly interpret posttreatment imaging and may help prevent further complication.

Correlation of a priori DCE-MRI and (1)H-MRS data with molecular markers in neck nodal metastases: Initial analysis

The aim of the present study is to correlate non-invasive, pretreatment biological imaging (dynamic contrast enhanced-MRI [DCE-MRI] and proton magnetic resonance spectroscopy [(1)H-MRS]) findings with specific molecular marker data in neck nodal metastases of head and neck squamous cell carcinoma (HNSCC) patients. Pretreatment DCE-MRI and (1)H-MRS were performed on neck nodal metastases of 12 patients who underwent surgery. Surgical specimens were analyzed with immunohistochemistry (IHC) assays for: Ki-67 (reflecting cellular proliferation), vascular endothelial growth factor (VEGF) (the "endogenous marker" of tumor vessel growth), carbonic anhydrase (CAIX), hypoxia inducible transcription factor (HIF-1α), and human papillomavirus (HPV). Additionally, necrosis was estimated based on H&E staining. The Spearman correlation was used to compare DCE-MRI, (1)H-MRS, and molecular marker data. A significant correlation was observed between DCE-MRI parameter std(k(ep)) and VEGF IHC expression level (rho=0.81, p=0.0001). Furthermore, IHC expression levels of Ki-67 inversely correlated with std(K(trans)) and std(v(e)) (rho=-0.71; p=0.004, and rho=-0.73; p=0.003, respectively). Other DCE-MRI, (1)H-MRS and IHC values did not show significant correlation. The results of this preliminary study indicate that the level of heterogeneity of perfusion in metastatic HNSCC seems positively correlated with angiogenesis, and inversely correlated with proliferation. These results are preliminary in nature and are indicative, and not definitive, trends portrayed in HNSCC patients with nodal disease. Future studies with larger patient populations need to be carried out to validate and clarify our preliminary findings.

Squamous cell carcinoma of the head and neck-The role of diffusion and perfusion imaging in tumor recurrence and follow-up

Computed tomography and magnetic resonance imaging-based techniques of functional imaging are proven to be sensitive and reliable tools for detection and staging of head and neck cancer. These new techniques enable to visualize and differentiate subtle pathologic changes before they become evident on standard cross-sectional images. However, it is their role in evaluating possible recurrence and estimation of treatment response that holds the biggest promise. This article describes the role and usefulness of diffusion and perfusion in detecting recurrence and follow-up in patients with head and neck squamous cell carcinoma.

Non-invasive imaging of angiogenesis in head and neck squamous cell carcinoma

Squamous cell carcinoma of the head and neck (HNSCC) is the seventh most common cancer in the United States. Angiogenesis, the process by which new blood vessels are formed, is an essential element at the basis of both tumor growth and metastases. This review discusses pertinent aspects of the role of imaging modalities in assessing angiogenesis and anti-angiogenic therapy in advanced HNSCC.

Cancer of the oral cavity and oropharynx

Tumours in the oral cavity and oropharynx differ in presentation and prognosis and the detection of spread of tumour from one subsite to another is essential for the T-staging. This article reviews the anatomy and describes the pattern of spread of different cancers arising in the oral cavity and oropharynx; the imaging findings on computerized tomography and magnetic resonance imaging are also described. Brief mention is made on the role of newer imaging modalities such as [¹⁸F]fluorodeoxyglucose-positron emission tomography/computed tomography, perfusion studies and diffusion-weighted magnetic resonance imaging.

Functional imaging of head and neck cancers

PURPOSE OF REVIEW

Functional imaging including single photon emission computed tomography, PET and MRI techniques in head and neck squamous cell cancer allows disease characterization beyond structure and morphology.

RECENT FINDINGS

In patients without clinical signs of lymph node involvement, sensitivity of fluoro-2-deoxy-D-glucose PET is only 50%. This has led to the use of sentinel lymph node scintigraphy that seems to be a valid alternative to elective stage dissection. Additionally, the use of single-photon emission computed tomography-computed tomography imaging enables a more accurate localization of the sentinel lymph node scintigraphy. The fluoro-2-deoxy-D-glucose uptake intensity of the head and neck squamous cell carcinoma sites is related to locoregional control and overall survival. In case of suspicion for residual or recurrent head and neck squamous cell carcinoma after surgery or (chemo)radiotherapy, fluoro-2-deoxy-D-glucose-PET has a high sensitivity and seems to be cost-effective in selecting patients for direct laryngoscopy. Diffusion-weighted MRI in combination with size and morphological criteria is a strong predictor of presence of malignant lymph nodes. Initial reports indicate the use of diffusion-weighted imaging for response assessment as early as 1 week after beginning of radiochemotherapy. Perfusion MRI is studied for the measurement of drug effects on tumour (micro)vascularity and capillary permeability.

SUMMARY

Functional imaging improves the initial staging and the detection of residual or recurrent disease following therapy.

Combined PET/MRI: a new dimension in whole-body oncology imaging?

INTRODUCTION

Hybrid imaging systems providing morphological and functional data in a single session have been available for oncological imaging for some time. So far, computed tomography (CT) has been the morphological method-of-choice for inclusion into these hybrid imaging systems. However, recently, research has focused on hardware-based fusion of function with magnetic resonance imaging (MRI) rather than CT.

OBJECTIVES

Now that the first head-only positron emission tomography (PET)/MRI systems have been installed and whole-body systems are to be expected in the near future, potential indications in clinical oncology have to be addressed.

DISCUSSION

This article discusses potential indications of PET/MRI in whole-body oncology imaging. Potential advantages and disadvantages compared with currently available hybrid imaging systems will be reviewed.