Machine learning based on magnetic resonance imaging and clinical parameters helps predict mesenchymal-epithelial transition factor expression in oral tongue squamous cell carcinoma: a pilot study

OBJECTIVES

This study aimed to develop machine learning models to predict phosphorylated mesenchymal-epithelial transition factor (p-MET) expression in oral tongue squamous cell carcinoma (OTSCC) using magnetic resonance imaging (MRI)-derived texture features and clinical features.

METHODS

Thirty-four patients with OTSCC were retrospectively collected. Texture features were derived from preoperative MR images, including T2WI, apparent diffusion coefficient mapping, and contrast-enhanced (ce)-T1WI. Dimension reduction was performed consecutively with reproducibility analysis and an information gain algorithm. Five machine learning methods-AdaBoost, logistic regression (LR), naïve Bayes (NB), random forest (RF), and support vector machine (SVM)-were adopted to create models predicting p-MET expression. Their performance was assessed with fivefold cross-validation.

RESULTS

In total, 22 and 12 cases showed low and high p-MET expression, respectively. After dimension reduction, 3 texture features (ADC-Minimum, ce-T1WI-Imc2, and ce-T1WI-DependenceVariance) and 2 clinical features (depth of invasion [DOI] and T-stage) were selected with good reproducibility and best correlation with p-MET expression levels. The RF model yielded the best overall performance, correctly classifying p-MET expression status in 87.5% of OTSCCs with an area under the receiver operating characteristic curve of 0.875.

CONCLUSION

Differences in p-MET expression in OTSCCs can be noninvasively reflected in MRI-based texture features and clinical parameters. Machine learning can potentially predict biomarker expression levels, such as MET, in patients with OTSCC.

T1 and T2 mapping for identifying malignant lymph nodes in head and neck squamous cell carcinoma

BACKGROUND

This study seeks to assess the utility of T1 and T2 mapping in distinguishing metastatic lymph nodes from reactive lymphadenopathy in patients with head and neck squamous cell carcinoma (HNSCC), using diffusion-weighted imaging (DWI) as a comparison.

METHODS

Between July 2017 and November 2019, 46 HNSCC patients underwent neck MRI inclusive of T1 and T2 mapping and DWI. Quantitative measurements derived from preoperative T1 and T2 mapping and DWI of metastatic and non-metastatic lymph nodes were compared using independent samples t-test or Mann-Whitney U test. Receiver operating characteristic curves and the DeLong test were employed to determine the most effective diagnostic methodology.

RESULTS

We examined a total of 122 lymph nodes, 45 (36.9%) of which were metastatic proven by pathology. Mean T2 values for metastatic lymph nodes were significantly lower than those for benign lymph nodes (p < 0.001). Conversely, metastatic lymph nodes exhibited significantly higher apparent diffusion coefficient (ADC) and standard deviation of T1 values (T1SD) (p < 0.001). T2 generated a significantly higher area under the curve (AUC) of 0.890 (0.826-0.954) compared to T1SD (0.711 [0.613-0.809]) and ADC (0.660 [0.562-0.758]) (p = 0.007 and p < 0.001). Combining T2, T1SD, ADC, and lymph node size achieved an AUC of 0.929 (0.875-0.983), which did not significantly enhance diagnostic performance over using T2 alone (p = 0.089).

CONCLUSIONS

The application of T1 and T2 mapping is feasible in differentiating metastatic from non-metastatic lymph nodes in HNSCC and can improve diagnostic efficacy compared to DWI.

Evaluation of the efficacy of diffusion-weighted magnetic resonance imaging and apparent diffusion coefficients in the diagnosis of maxillary diseases

OBJECTIVE

We investigated the efficacy of using diffusion-weighted imaging (DWI) with quantitative apparent diffusion coefficient (ADC) mapping in the diagnosis of maxillary diseases.

STUDY DESIGN

We evaluated 146 cases of maxillary diseases (32 malignant tumors, 11 benign tumors, 28 maxillary cysts, 60 cases of maxillary sinusitis, and 15 maxillary sinus retention cysts) that had been examined using magnetic resonance imaging. The DWI sequence was obtained with b values of 0 and 800 s/mm2 and ADC values were calculated. We used one-way analysis of variance and the Tukey honestly significant difference test to identify differences within and between the types of diseases.

RESULTS

Mean ADC values for malignant tumors (1.07 × 10-3 mm2 s-1) were significantly lower than ADCs for benign tumors (1.85 × 10-3 mm2 s-1), maxillary cysts (1.77 × 10-3 mm2 s-1), maxillary sinusitis (2.34 × 10-3 mm2 s-1), and maxillary sinus retention cysts (2.52 × 10-3 mm2 s-1), with P < 0.001.   Mean ADC differed significantly between all disease types except between maxillary sinusitis and maxillary sinus retention cysts. ADC values also significantly differed between specific lesions within the malignant tumor and maxillary cyst groups.

CONCLUSIONS

The use of ADC values can be useful in the differential diagnosis of malignant maxillary diseases, benign lesions, cysts, and inflammatory and reactive conditions.

Computed Tomography and Magnetic Resonance Imaging Findings Contribute to Differentiating Solid- and Nonsolid-Type Adenoid Cystic Carcinoma in Maxillary Sinus

PURPOSE

This study aimed to evaluate the imaging features of maxillary sinus adenoid cystic carcinoma (ACC) on computed tomography (CT) and magnetic resonance imaging (MRI) and to investigate the imaging differences between solid and nonsolid maxillary sinus ACC.

METHODS

We retrospectively reviewed 40 cases of histopathologically confirmed ACC of the maxillary sinus. All the patients underwent CT and MRI. Based on the histopathological characteristics, the patients were classified into 2 groups: ( a ) solid maxillary sinus ACC (n = 16) and ( b ) nonsolid maxillary sinus ACC (n = 24). Imaging features such as tumor size, morphology, internal structure, margin, type of bone destruction, signal intensity, enhancement changes, and perineural tumor spread on CT and MRI, were evaluated. The apparent diffusion coefficient (ADC) was measured. Comparisons of imaging features and ADC values were performed between the solid and nonsolid maxillary sinus ACC using χ 2 and nonparametric tests.

RESULTS

The internal structure, margin, type of bone destruction, and degree of enhancement significantly differed between solid and nonsolid maxillary sinus ACC (all P < 0.05). The ADC of the solid maxillary sinus ACC was considerably lower than that of the nonsolid maxillary sinus ( P < 0.05).

CONCLUSIONS

Computed tomography and MRI may aid in the differentiation of solid and nonsolid types of maxillary sinus ACC.

PET/MR Imaging in Head and Neck Cancer

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

Prospective evaluation of in vivo and phantom repeatability and reproducibility of diffusion-weighted MRI sequences on 1.5 T MRI-linear accelerator (MR-Linac) and MR simulator devices for head and neck cancers

INTRODUCTION

Diffusion-weighted imaging (DWI) on MRI-linear accelerator (MR-linac) systems can potentially be used for monitoring treatment response and adaptive radiotherapy in head and neck cancers (HNC) but requires extensive validation. We performed technical validation to compare six total DWI sequences on an MR-linac and MR simulator (MR sim) in patients, volunteers, and phantoms.

METHODS

Ten human papillomavirus-positive oropharyngeal cancer patients and ten healthy volunteers underwent DWI on a 1.5 T MR-linac with three DWI sequences: echo planar imaging (EPI), split acquisition of fast spin echo signals (SPLICE), and turbo spin echo (TSE). Volunteers were also imaged on a 1.5 T MR sim with three sequences: EPI, BLADE (vendor tradename), and readout segmentation of long variable echo trains (RESOLVE). Participants underwent two scan sessions per device and two repeats of each sequence per session. Repeatability and reproducibility within-subject coefficient of variation (wCV) of mean ADC were calculated for tumors and lymph nodes (patients) and parotid glands (volunteers). ADC bias, repeatability/reproducibility metrics, SNR, and geometric distortion were quantified using a phantom.

RESULTS

In vivo repeatability/reproducibility wCV for parotids were 5.41%/6.72%, 3.83%/8.80%, 5.66%/10.03%, 3.44%/5.70%, 5.04%/5.66%, 4.23%/7.36% for EPIMR-linac, SPLICE, TSE, EPIMR sim, BLADE, RESOLVE. Repeatability/reproducibility wCV for EPIMR-linac, SPLICE, TSE were 9.64%/10.28%, 7.84%/8.96%, 7.60%/11.68% for tumors and 7.80%/9.95%, 7.23%/8.48%, 10.82%/10.44% for nodes. All sequences except TSE had phantom ADC biases within ± 0.1x10-3 mm2/s for most vials (EPIMR-linac, SPLICE, and BLADE had 2, 3, and 1 vials out of 13 with larger biases, respectively). SNR of b = 0 images was 87.3, 180.5, 161.3, 171.0, 171.9, 130.2 for EPIMR-linac, SPLICE, TSE, EPIMR sim, BLADE, RESOLVE.

CONCLUSION

MR-linac DWI sequences demonstrated near-comparable performance to MR sim sequences and warrant further clinical validation for treatment response assessment in HNC.

A review of diffusion-weighted magnetic resonance imaging in head and neck cancer patients for treatment evaluation and prediction of radiation-induced xerostomia

The incidence of head and neck cancers (HNC) is rising worldwide especially with HPV-related oropharynx squamous cell carcinoma. The standard of care for the majority of patients with locally advanced pharyngeal disease is curative-intent radiotherapy (RT) with or without concurrent chemotherapy. RT-related toxicities remain a concern due to the close proximity of critical structures to the tumour, with xerostomia inflicting the most quality-of-life burden. Thus, there is a paradigm shift towards research exploring the use of imaging biomarkers in predicting treatment outcomes. Diffusion-weighted imaging (DWI) is a functional MRI feature of interest, as it quantifies cellular changes through computation of apparent diffusion coefficient (ADC) values. DWI has been used in differentiating HNC lesions from benign tissues, and ADC analyses can be done to evaluate tumour responses to RT. It is also useful in healthy tissues to identify the heterogeneity and physiological changes of salivary glands to better understand the inter-individual differences in xerostomia severity. Additionally, DWI is utilised in irradiated salivary glands to produce ADC changes that correlate to clinical xerostomia. The implementation of DWI into multi-modal imaging can help form prognostic models that identify patients at risk of severe xerostomia, and thus guide timely interventions to mitigate these toxicities.

Diagnostic efficacy of positron emission computerized tomography scans in suspicious laryngeal findings postorgan preservation treatment

BACKGROUND

Larynx preservation protocols (LPP) for glottic primary squamous cell carcinoma has gained popularity worldwide. Direct laryngoscopy (DL) with biopsy is mandated when recurrence is suspected. The efficacy of 18Fluoro-deoxy-glucose positron emission computerized tomography (PET-CT) as alternative first-line diagnostic investigation in suspected recurrence was evaluated.

METHODS

A retrospective study of patients with suspicious fiber-optic findings at more than 12 weeks after LPP. Sensitivity, specificity, and the negative predictive value (NPV) of DL and PET-CT were compared.

RESULTS

Seventy-two patients presenting 105 cases of suspicious events were included in this study. Fifty-two events were initially investigated by DL and 53 events by PET-CT. The sensitivity of DL and PET-CT was 56.25% and 100%, respectively. The NPV was 84% for DL and 100% for PET-CT (p = 0.015).

CONCLUSION

Negative PET scans after LPP are highly accurate in ruling out recurrent/persistent disease and may spare the patient from negative biopsies.

Quantitative Diffusion-Weighted Imaging Analyses to Predict Response to Neoadjuvant Immunotherapy in Patients with Locally Advanced Head and Neck Carcinoma

BACKGROUND

Neoadjuvant immune checkpoint blockade (ICB) prior to surgery may induce early pathological responses in head and neck squamous cell carcinoma (HNSCC) patients. Routine imaging parameters fail to diagnose these responses early on. Magnetic resonance (MR) diffusion-weighted imaging (DWI) has proven to be useful for detecting HNSCC tumor mass after (chemo)radiation therapy.

METHODS

32 patients with stage II-IV, resectable HNSCC, treated at a phase Ib/IIa IMCISION trial (NCT03003637), were retrospectively analyzed using MR-imaging before and after two doses of single agent nivolumab (anti-PD-1) (n = 6) or nivolumab with ipilimumab (anti-CTLA-4) ICB (n = 26). The primary tumors were delineated pre- and post-treatment. A total of 32 features were derived from the delineation and correlated with the tumor regression percentage in the surgical specimen.

RESULTS

MR-DWI data was available for 24 of 32 patients. Smaller baseline tumor diameter (p = 0.01-0.04) and higher sphericity (p = 0.03) were predictive of having a good pathological response to ICB. Post-treatment skewness and the change in skewness between MRIs were negatively correlated with the tumor's regression (p = 0.04, p = 0.02).

CONCLUSION

Pre-treatment DWI tumor diameter and sphericity may be quantitative biomarkers for the prediction of an early pathological response to ICB. Furthermore, our data indicate that ADC skewness could be a marker for individual response evaluation.

Additional Diffusion-Weighted Imaging with Background Body Signal Suppression (DWIBS) Improves Pre-Therapeutical Detection of Early-Stage (pT1a) Glottic Cancer: A Feasibility and Interobserver Reliability Study

(1) Background: Early-stage glottic cancer is easily missed on magnetic resonance imaging (MRI). Diffusion-weighted imaging (DWI) may improve diagnostic accuracy. Therefore, our aim was to assess the value of adding diffusion-weighted imaging with background body signal suppression (DWIBS) to pre-therapeutic MRI staging. (2) Methods: Two radiologists with 8 and 13 years of experience, blinded to each other's findings, initially interpreted only standard MRI, later DWIBS alone, and afterward, standard MRI + DWIBS in 41 patients with histopathologically proven pT1a laryngeal cancer of the glottis. (3) Results: Detectability rates with standard MRI, DWIBS only, and standard MRI + DWIBS were 68-71%, 63-66%, and 73-76%, respectively. Moreover, interobserver reliability was calculated as good (κ = 0.712), very good (κ = 0.84), and good (κ = 0.69) for standard MRI, DWIBS only, and standard MRI + DWIBS, respectively. (4) Conclusions: Standard MRI, DWIBS alone, and standard MRI + DWIBS showed an encouraging detection rate, as well as distinct interobserver reliability in the diagnosis of early-stage laryngeal cancer when compared to the definitive histopathologic report.

Magnetic Resonance-Guided Radiation Therapy for Head and Neck Cancers

Despite the significant evolution of radiation therapy (RT) techniques in recent years, many patients with head and neck cancer still experience significant toxicities during and after treatments. The increased soft tissue contrast and functional sequences of magnetic resonance imaging (MRI) are particularly attractive in head and neck cancer and have led to the increasing development of magnetic resonance-guided RT (MRgRT). This approach refers to the inclusion of the additional information acquired from a diagnostic or planning MRI in radiation treatment planning, and now extends to online high-quality daily imaging generated by the recently developed MR-Linac. MRgRT holds numerous potentials, including enhanced baseline and planning evaluations, anatomical and functional treatment adaptation, potential for hypofractionation, and multiparametric assessment of response. This article offers a structured review of the current literature on these established and upcoming roles of MRI for patients with head and neck cancer undergoing RT.

Standardised lesion segmentation for imaging biomarker quantitation: a consensus recommendation from ESR and EORTC

BACKGROUND

Lesion/tissue segmentation on digital medical images enables biomarker extraction, image-guided therapy delivery, treatment response measurement, and training/validation for developing artificial intelligence algorithms and workflows. To ensure data reproducibility, criteria for standardised segmentation are critical but currently unavailable.

METHODS

A modified Delphi process initiated by the European Imaging Biomarker Alliance (EIBALL) of the European Society of Radiology (ESR) and the European Organisation for Research and Treatment of Cancer (EORTC) Imaging Group was undertaken. Three multidisciplinary task forces addressed modality and image acquisition, segmentation methodology itself, and standards and logistics. Devised survey questions were fed via a facilitator to expert participants. The 58 respondents to Round 1 were invited to participate in Rounds 2-4. Subsequent rounds were informed by responses of previous rounds.

RESULTS/CONCLUSIONS

Items with ≥ 75% consensus are considered a recommendation. These include system performance certification, thresholds for image signal-to-noise, contrast-to-noise and tumour-to-background ratios, spatial resolution, and artefact levels. Direct, iterative, and machine or deep learning reconstruction methods, use of a mixture of CE marked and verified research tools were agreed and use of specified reference standards and validation processes considered essential. Operator training and refreshment were considered mandatory for clinical trials and clinical research. Items with a 60-74% agreement require reporting (site-specific accreditation for clinical research, minimal pixel number within lesion segmented, use of post-reconstruction algorithms, operator training refreshment for clinical practice). Items with ≤ 60% agreement are outside current recommendations for segmentation (frequency of system performance tests, use of only CE-marked tools, board certification of operators, frequency of operator refresher training). Recommendations by anatomical area are also specified.

Arterial spin labeling and diffusion-weighted imaging for identification of retropharyngeal lymph nodes in patients with nasopharyngeal carcinoma

Background

To evaluate the parameters derived from arterial spin labeling (ASL) and multi-b-value diffusion-weighted imaging (DWI) for differentiating retropharyngeal lymph nodes (RLNs) in patients with nasopharyngeal carcinoma (NPC).

Methods

This prospective study included 50 newly diagnosed NPC and 23 healthy control (HC) participants. RLNs of NPC were diagnosed according to the follow-up MRI after radiotherapy. Parameters derived from ASL and multi-b-value DWI, and RLNs axial size on pre-treatment MRI among groups were compared. Receiver operating characteristic curve (ROC) was used to analyze the diagnostic efficiency.

Results

A total of 133 RLNs were collected and divided into a metastatic group (n = 71) and two non-metastatic groups (n = 62, including 29 nodes from NPC and 33 nodes from HC). The axial size, blood flow (BF), and apparent diffusion coefficient (ADC) of RLNs were significantly different between the metastasis and the non-metastasis group. For NPC patients with a short axis < 5 mm or < 6 mm, or long axis < 7 mm, if BF > 54 mL/min/100 g or ADC ≤ 0.95 × 10⁻³ mm²/s, the RLNs were still considered metastatic. Compared with the index alone, a combination of size and functional parameters could improve the accuracy significantly, except the long axis combined with ADC; especially, combined size with BF exhibited better performance with an accuracy of 91.00–92.00%.

Conclusions

ASL and multi-b-value DWI could help determine the N stage of NPC, while the BF combination with RLNs size may significantly improve the diagnostic efficiency.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40644-022-00480-4.

Utility of diffusion MRI characteristics of cervical lymph nodes as disease classifier between patients with head and neck squamous cell carcinoma and healthy volunteers

Diffusion MRI characteristics assessed by apparent diffusion coefficient (ADC) histogram analysis in head and neck squamous cell carcinoma (HNSCC) have been reported as helpful in classifying tumours based on diffusion characteristics. There is little reported on HNSCC lymph nodes classification by diffusion characteristics. The aim of this study was to determine whether pretreatment nodal microstructural diffusion MRI characteristics can classify diseased nodes of patients with HNSCC from normal nodes of healthy volunteers. Seventy-nine patients with histologically confirmed HNSCC prior to chemoradiotherapy, and eight healthy volunteers, underwent diffusion-weighted (DW) MRI at a 1.5-T MR scanner. Two radiologists contoured lymph nodes on DW (b = 300 s/m² ) images. ADC, distributed diffusion coefficient (DDC) and alpha (α) values were calculated by monoexponential and stretched exponential models. Histogram analysis metrics of drawn volume were compared between patients and volunteers using a Mann-Whitney test. The classification performance of each metric between the normal and diseased nodes was determined by receiver operating characteristic (ROC) analysis. Intraclass correlation coefficients determined interobserver reproducibility of each metric based on differently drawn ROIs by two radiologists. Sixty cancerous and 40 normal nodes were analysed. ADC histogram analysis revealed significant differences between patients and volunteers (p ≤0.0001 to 0.0046), presenting ADC distributions that were more skewed (1.49 for patients, 1.03 for volunteers; p = 0.0114) and 'peaked' (6.82 for patients, 4.20 for volunteers; p = 0.0021) in patients. Maximum ADC values exhibited the highest area under the curve ([AUC] 0.892). Significant differences were revealed between patients and volunteers for DDC and α value histogram metrics (p ≤0.0001 to 0.0044); the highest AUC were exhibited by maximum DDC (0.772) and the 25th percentile α value (0.761). Interobserver repeatability was excellent for mean ADC (ICC = 0.88) and the 25th percentile α value (ICC = 0.78), but poor for all other metrics. These results suggest that pretreatment microstructural diffusion MRI characteristics in lymph nodes, assessed by ADC and α value histogram analysis, can identify nodal disease.

The value of diffusion-weighted imaging in the diagnosis of medication-related osteonecrosis of the jaws

OBJECTIVE

The purpose of this study was to assess apparent diffusion coefficient (ADC) values associated with medication-related osteonecrosis of the jaws (MRONJ) at each stage of the disease compared to controls.

STUDY DESIGN

The magnetic resonance imaging data of 38 patients in the 4 stages of MRONJ and 10 controls were analyzed. Mean ADC values of bone marrow in the controls and patients in each stage of MRONJ were calculated. The significance of differences was analyzed by using the Kruskal-Wallis test and post-hoc Mann-Whitney tests with Bonferroni adjustment. A receiver operating characteristic (ROC) curve was plotted to distinguish controls from MRONJ stage 0. P < .05 was considered statistically significant.

RESULTS

The mean ADC values of controls and stages 0 to 3 were significantly different, with the lowest value in the controls (P < .001). ROC analysis revealed a cutoff ADC value of 1.06 × 10^-3 mm²/s to distinguish between the control group and MRONJ stage 0 patients, producing values of sensitivity, specificity, accuracy, and area under the ROC curve ranging from 0.89 to 0.94.

CONCLUSIONS

The ADC values of bone marrow affected by MRONJ are significantly different among controls and stages 0 to 3. ADC values may be useful for distinguishing normal from MRONJ stage 0.

Diffusion-Weighted Imaging of the Head and Neck (Including Temporal Bone)

Diffusion techniques provide valuable information when performing head and neck imaging. This information can be used to detect the presence or absence of pathology, refine differential diagnosis, determine the location for biopsy, assess response to treatment, and prognosticate outcomes. For example, when certain technical factors are taken into consideration, diffusion techniques prove indispensable in assessing for residual cholesteatoma following middle ear surgery. In other scenarios, pretreatment apparent diffusion coefficient values may assist in prognosticating outcomes in laryngeal cancer and likelihood of response to radiation therapy. As diffusion techniques continue to advance, so too will its clinical utility.

Intravoxel Incoherent Motion Magnetic Resonance Imaging for Prediction of Induction Chemotherapy Response in Locally Advanced Hypopharyngeal Carcinoma: Comparison With Model-Free Dynamic Contrast-Enhanced Magnetic Resonance Imaging

BACKGROUND

Multiparametric intravoxel incoherent motion (IVIM) provides diffusion and perfusion information for the treatment prediction of cancer. However, the superiority of IVIM over dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) in locally advanced hypopharyngeal carcinoma (LAHC) remains unclear.

PURPOSE

To compare the diagnostic performance of IVIM and model-free DCE in assessing induction chemotherapy (IC) response in patients with LAHC.

STUDY TYPE

Prospective.

POPULATION

Forty-two patients with LAHC.

FIELD STRENGTH/SEQUENCE

3.0 T MRI, including IVIM (12 b values, 0-800 seconds/mm² ) with a single-shot echo planar imaging sequence and DCE-MRI with a volumetric interpolated breath-hold examination sequence. IVIM MRI is a commercially available sequence and software for calculation and analysis from vendor.

ASSESSMENT

The IVIM-derived parameters (diffusion coefficient [D], pseudodiffusion coefficient [D*], and perfusion fraction [f]) and DCE-derived model-free parameters (Wash-in, time to maximum enhancement [Tmax], maximum enhancement [Emax], area under enhancement curve [AUC] over 60 seconds [AUC₆₀ ], and whole area under enhancement curve [AUC_w ]) were measured. At the end of IC, patients with complete or partial response were classified as responders according to the Response Evaluation Criteria in Solid Tumors.

STATISTICAL TESTS

The differences of parameters between responders and nonresponders were assessed using Mann-Whitney U tests. The performance of parameters for predicting IC response was evaluated by the receiver operating characteristic curves.

RESULTS

Twenty-three (54.8%) patients were classified as responders. Compared with nonresponders, the perfusion parameters D*, f, f × D*, and AUC_w were significantly higher whereas Wash-in was lower in responders (all P-values <0.05). The f × D* outperformed other parameters, with an AUC of 0.84 (95% confidence interval [CI]: 0.69-0.93), sensitivity of 79.0% (95% CI: 54.4-93.9), and specificity of 82.6% (95% CI: 61.2-95.0).

DATA CONCLUSION

The IVIM MRI technique may noninvasively help predict the IC response before treatment in patients with LAHC.

LEVEL OF EVIDENCE

2 TECHNICAL EFFICACY: Stage 2.

Relationships between apparent diffusion coefficient (ADC) histogram analysis parameters and PD-L 1-expression in head and neck squamous cell carcinomas: a preliminary study

BACKGROUND

Immunotherapy has become a cornerstone of the modern cancer treatment. It might be crucial to predict its expression non-invasively by imaging. The present study used diffusion-weighted imaging (DWI) quantified by whole lesion apparent diffusion coefficient (ADC) values to elucidate possible associations with programmed cell death ligand 1(PD-L1) expression in head and neck squamous cell cancer (HNSCC).

PATIENTS AND METHODS

Overall, 29 patients with primary HNSCC of different localizations were involved in the study. DWI was obtained by using a sequence with b _- values of 0 and 800 s/mm² on a 3 T MRI. ADC values were evaluated with a whole lesion measurement and a histogram approach. PD-L1 expression was estimated on bioptic samples before any form of treatment using 3 scores, tumor positive score (TPS), immune cell score (ICS), and combined positive score (CPS).

RESULTS

An inverse correlation between skewness derived from ADC values and ICS was identified (r = -0.38, p = 0.04). ADC_max tended to correlate with ICS (r = -0.35, p = 0.06). Other ADC parameters did not show any association with the calculated scores.

CONCLUSIONS

There is a weak association between skewness derived from ADC values and PD-L1 expression in HNSCC, which might not be strong enough to predict PD-L1 expression in clinical routine. Presumably, ADC values are more influenced by complex histopathology compartments, comprising cellular and extracellular aspects of tumors than only of a single subset of tumor associated cells.

Automatic Tumor Segmentation With a Convolutional Neural Network in Multiparametric MRI: Influence of Distortion Correction

Precise tumor segmentation is a crucial task in radiation therapy planning. Convolutional neural networks (CNNs) are among the highest scoring automatic approaches for tumor segmentation. We investigate the difference in segmentation performance of geometrically distorted and corrected diffusion-weighted data using data of patients with head and neck tumors; 18 patients with head and neck tumors underwent multiparametric magnetic resonance imaging, including T2w, T1w, T2*, perfusion (k_trans), and apparent diffusion coefficient (ADC) measurements. Owing to strong geometrical distortions in diffusion-weighted echo planar imaging in the head and neck region, ADC data were additionally distortion corrected. To investigate the influence of geometrical correction, first 14 CNNs were trained on data with geometrically corrected ADC and another 14 CNNs were trained using data without the correction on different samples of 13 patients for training and 4 patients for validation each. The different sets were each trained from scratch using randomly initialized weights, but the training data distributions were pairwise equal for corrected and uncorrected data. Segmentation performance was evaluated on the remaining 1 test-patient for each of the 14 sets. The CNN segmentation performance scored an average Dice coefficient of 0.40 ± 0.18 for data including distortion-corrected ADC and 0.37 ± 0.21 for uncorrected data. Paired t test revealed that the performance was not significantly different (P = .313). Thus, geometrical distortion on diffusion-weighted imaging data in patients with head and neck tumor does not significantly impair CNN segmentation performance in use.

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.

Clinical utility of apparent diffusion coefficient and diffusion-weighted magnetic resonance imaging for resectability assessment of head and neck tumors with skull base invasion

BACKGROUND

The usefulness of apparent diffusion coefficient (ADC) and diffusion-weighted magnetic resonance imaging (DWI) in the detection of malignant tumors has been reported. The purpose of this study is to clarify the role of ADC and DWI for diagnosis of skull base tumors.

METHODS

A total of 27 patients with head and neck tumors with skull base invasions undergoing skull base surgery were enrolled in this study. Pathological findings of dural invasion and bone invasion were compared with the diagnostic imaging.

RESULTS

Advanced magnetic resonance imaging techniques revealed that ADC values in regions of pathological bone and dural invasions were significantly lower than in regions of no invasion. The area under the curve of ADC in bone invasions and dural invasions were 0.957 and 0.894, respectively.

CONCLUSIONS

Our findings indicate that ADC and DWI are useful tools for the diagnosis of head and neck tumors with skull base invasion.

A Review of Modern Radiation Therapy Dose Escalation in Locally Advanced Head and Neck Cancer

The management of head and neck cancer is complex and often involves multimodality treatment. Certain groups of patients, such as those with inoperable or advanced disease, are at higher risk of treatment failure and may therefore benefit from radiation therapy dose escalation. This can be difficult to achieve without increasing toxicity. However, the combination of modern treatment techniques and increased research into the use of functional imaging modalities that assist with target delineation allows researchers to push this boundary further. This review aims to summarise modern dose escalation trials to identify the impact on disease outcomes and explore the growing role of functional imaging modalities. Studies experimenting with dose escalation above standard fractionated regimens as outlined in National Comprehensive Cancer Network guidelines using photon therapy were chosen for review. Seventeen papers were considered suitable for inclusion in the review. Eight studies investigated nasopharyngeal cancer, with the remainder treating a range of subsites. Six studies utilised functional imaging modalities for target delineation. Doses as high as 85.9 Gy in 2.6 Gy fractions (EQD2 90.2 Gy₁₀) were reportedly delivered with the aid of functional imaging modalities. Dose escalation in nasopharyngeal cancer resulted in 3-year locoregional control rates of 86.6-100% and overall survival of 82-95.2%. For other mucosal primary tumour sites, 3-year locoregional control reached 68.2-85.9% and 48.4-54% for overall survival. There were no clear trends in acute or late toxicity across studies, regardless of dose or addition of chemotherapy. However, small cohort sizes and short follow-up times may have resulted in under-reporting. This review highlights the future possibilities of radiation therapy dose escalation in head and neck cancer and the potential for improved target delineation with careful patient selection and the assistance of functional imaging modalities.

Application of diffusion-weighted magnetic resonance imaging in the diagnosis of odontogenic lesions: a systematic review

OBJECTIVES

This systematic literature review addresses the use of diffusion-weighted magnetic resonance imaging (DWI) and apparent diffusion coefficient (ADC) for the evaluation of benign maxillomandibular odontogenic lesions.

STUDY DESIGN

Databases were searched, and original research studies or case report manuscripts up to April 2019 were included, using the keyword "diffusion," combined with the keywords "maxillofacial pathology," "oral pathology," "odontogenic tumors," "dental tissue neoplasms," "odontogenic cysts," and the histologic denomination of benign odontogenic lesions, according to the World Health Organization classification. Only English language articles and studies pertaining to DWI were selected.

RESULTS

Fifteen investigations (11 original articles and 4 case reports) of distinct benign odontogenic lesions were included. Most studies did not include exclusively odontogenic lesions in their samples.

CONCLUSIONS

It is too early to reach a conclusion that DWI and ADC can provide useful information in the differentiation of the histologic type of some benign odontogenic lesions on the basis of available data in the literature.

Textural features on 18F-FDG PET/CT and dynamic contrast-enhanced MR imaging for predicting treatment response and survival of patients with hypopharyngeal carcinoma

The utility of multimodality molecular imaging for predicting treatment response and survival of patients with hypopharyngeal carcinoma remains unclear. Here, we sought to investigate whether the combination of different molecular imaging parameters may improve outcome prediction in this patient group.Patients with pathologically proven hypopharyngeal carcinoma scheduled to undergo chemoradiotherapy (CRT) were deemed eligible. Besides clinical data, parameters obtained from pretreatment 2-deoxy-2-[fluorine-18]fluoro-D-glucose positron emission tomography/computed tomography (F-FDG PET/CT), dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI), and diffusion-weighted MRI were analyzed in relation to treatment response, recurrence-free survival (RFS), and overall survival (OS).A total of 61 patients with advanced-stage disease were examined. After CRT, 36% of the patients did not achieve a complete response. Total lesion glycolysis (TLG) and texture feature entropy were found to predict treatment response. The transfer constant (K), TLG, and entropy were associated with RFS, whereas K, blood plasma volume (Vp), standardized uptake value (SUV), and entropy were predictors of OS. Different scoring systems based on the sum of PET- or MRI-derived prognosticators enabled patient stratification into distinct prognostic groups (P <.0001). The complete response rate of patients with a score of 2 was significantly lower than those of patients with a score 1 or 0 (14.7% vs 58.9% vs 75.7%, respectively, P = .007, respectively). The combination of PET- and DCE-MRI-derived independent risk factors allowed a better survival stratification than the TNM staging system (P <.0001 vs .691, respectively).Texture features on F-FDG PET/CT and DCE-MRI are clinically useful to predict treatment response and survival in patients with hypopharyngeal carcinoma. Their combined use in prognostic scoring systems may help these patients benefit from tailored treatment and obtain better oncological results.

Apparent diffusion coefficient (ADC) histogram analysis: differentiation of benign from malignant parotid gland tumors using readout-segmented diffusion-weighted imaging

OBJECTIVES

To explore the utility of whole-lesion apparent diffusion coefficient (ADC) histogram analysis for differentiating parotid gland tumors following readout-segmented diffusion-weighted imaging (RESOLVE).

METHODS

80 patients (40 with pleomorphic adenomas, 14 with Warthin tumors, and 26 with malignant parotid gland tumors) who underwent routine head-and-neck MRI and RESOLVE examinations, were retrospectively evaluated. RESOLVE data were acquired from a MAGNETOM Skyra 3T MR system. Eleven whole-lesion histogram parameters derived from histogram analysis (ADC_mean, ADC_minimum, ADC_maximum, ADC_1th, ADC_10th, ADC_50th, ADC_90th, ADC_99th, skewness, variance and kurtosis) were calculated for each patient using MaZda. Receiver operating characteristic (ROC) curve analysis was used to assess the diagnostic performance of the ADC for distinguishing among the three groups.

RESULTS

In total, nine parameters (ADC_minimum, ADC_maximum, ADC_mean, ADC_10th, ADC_50th, ADC_90th, ADC_99th, variance, skewness) were statistically significant (all p < 0.05) for all three groups, in the comparison of pleomorphic adenomas to Warthin tumors; the ADC_mean, ADC_50th, and skewness revealed high diagnostic efficiency with areas under the receiver operating characteristic curve of 0.976, 0.970, and 0.970, respectively. In the comparison of pleomorphic adenomas to malignant parotid gland tumors, these nine parameters were also found to be statistically different (all p < 0.05); the ADC_mean, ADC_10th and ADC_50th revealed high diagnostic efficiency with area under the curve of 0.851, 0.866, and 0.841, respectively. However, in the comparison of Warthin tumors to malignant parotid gland tumors, only three parameters (ADC_mean, ADC_50th, skewness) were statistically significant (all p < 0.05).

CONCLUSIONS

Whole-lesion ADC histograms are effective in differentiating common parotid gland tumors.

Tc-99m hydroxymethylene diphosphonate scintigraphy, computed tomography, and magnetic resonance imaging of osteonecrosis in the mandible: Osteoradionecrosis versus medication-related osteonecrosis of the jaw

Purpose

To present characteristic findings of Tc-99m hydroxymethylene diphosphonate (HMDP) scintigraphy, computed tomography (CT), and magnetic resonance (MR) imaging for osteonecrosis in the mandible, especially osteoradionecrosis (ORN) and medication-related osteonecrosis of the jaw (MRONJ).

Materials and Methods

Thirteen patients with MRONJ and 7 patients with ORN in the mandible underwent Tc-99m HMDP scintigraphy, CT, and MR imaging (T1-weighted images [T1WI], T2-weighted images [T2WI], short inversion time inversion recovery images [STIR]), diffusion-weighted images [DWI], and apparent diffusion coefficient [ADC] mapping). The associations of scintigraphy, CT, and MR imaging findings with MRONJ and ORN were analyzed using the chi-square test with the Pearson exact test.

Results

Thirteen patients with MRONJ and 7 patients with ORN in the mandible showed low signal intensity on T1WI and ADC mapping, high signal intensity on STIR and DWI, and increased uptake on scintigraphy. Periosteal bone proliferation on CT was observed in 69.2% of patients with MRONJ (9 of 13) versus 14.3% of patients with ORN (1 of 7) (P=0.019).

Conclusion

This study presented characteristic imaging findings of MRONJ and ORN on scintigraphy, CT, and MR imaging. Our results suggest that CT can be effective for detecting MRONJ and ORN.

Application of diffusion-weighted MR imaging with ADC measurement for distinguishing between the histopathological types of sinonasal neoplasms

PURPOSE

To evaluate the potential contribution of quantitative DWI parameters including ADC_mean and ADC_ratio values to help in distinguishing the histopathological types of sinonasal neoplasms.

METHODS

This retrospective study included 83 patients (50 males, 33 females; mean age 61 years) with pathologically proven untreated sinonasal neoplasms who have undergone diffusion-weighted MRI imaging from February 2010 to August 2017. Diffusion-weighted MRI was performed on a 3 T unit with b factors of 0 and 1000 s/mm², and ADC maps were generated. Mean ADC values of sinonasal tumors and ADC ratios (ADC_mean of the tumor to ADC_mean of pterygoid muscles) were compared with the histopathological diagnosis by utilizing the Kruskal-Wallis non-parametric test.

RESULTS

Mean ADC_mean and ADC_ratio were 0.8 (SD, ±0.4) × (10^-3 mm²/s) and 1.2 (SD, ±0.5), respectively, and each parameter was significantly different between histopathological types (p < 0.05). Mean ADC_mean and ADC_ratio were higher in adenoid cystic carcinoma (ACC) than in SCC, lymphoma, neuroendocrine carcinoma and sinonasal undifferentiated carcinoma (SNUC) (p < 0.05). Optimized ADC_mean thresholds of 0.79, 0.81, 0.74 and 0.78 (10^-3 mm²/s) achieved maximal discriminatory accuracies of 100%, 79%, 100% and 89% for ACC/SNUC, ACC/SCC, ACC/neuroendocrine carcinoma, and ACC/lymphoma, respectively.

CONCLUSIONS

The optimized ADC_mean threshold of 0.80 (10^-3 mm²/s) could be used to differentiate ACC from non-ACC sinonasal neoplasms with maximal discriminatory accuracy (82%) and sensitivity of 100%. However, there is considerable overlapping of the ADC_mean and ADC_ratio values among non-ACC sinonasal neoplasms hence surgical biopsy is still needed.

Functional imaging early during (chemo)radiotherapy for response prediction in head and neck squamous cell carcinoma; a systematic review

This systematic review gives an extensive overview of the current state of functional imaging during (chemo)radiotherapy to predict locoregional control (LRC) and overall survival (OS) for head and neck squamous cell carcinoma. MEDLINE and EMBASE were searched for literature until April 2018 assessing the predictive performance of functional imaging (computed tomography perfusion (CTp), MRI and positron-emission tomography (PET)) within 4 weeks after (chemo)radiotherapy initiation. Fifty-two studies (CTp: n = 4, MRI: n = 19, PET: n = 26, MRI/PET: n = 3) were included involving 1623 patients. Prognostic information was extracted according the PRISMA protocol. Pooled estimation and subgroup analyses were performed for comparable parameters and outcome. However, the heterogeneity of included studies limited the possibility for comparison. Early tumoral changes from (chemo)radiotherapy can be captured by functional MRI and ¹⁸F-FDG-PET and could allow for personalized treatment adaptation. Lesions showed potentially prognostic intratreatment changes in perfusion, diffusion and metabolic activity. Intratreatment ADC_mean increase (decrease of diffusion restriction) and low SUV_max (persistent low or decrease of ¹⁸F-FDG uptake) were most predictive of LRC. Intratreatment persistent high or increase of perfusion on CT/MRI (i.e. blood flow, volume, permeability) also predicted LRC. Low SUV_max and total lesion glycolysis (TLG) predicted favorable OS. The optimal timing to perform functional imaging to predict LRC or OS was 2-3 weeks after treatment initiation.

Use of Diffusion-Weighted Imaging and 18F-Fluorodeoxyglucose Positron Emission Tomography Combined With Computed Tomography in the Response Assessment for (Chemo)radiotherapy in Head and Neck Squamous Cell Carcinoma

AIMS

Our purpose was to assess the diagnostic accuracy and prognostic value of diffusion-weighted imaging (DWI) and ¹⁸F-fluorodeoxyglucose positron emission tomography combined with computed tomography (¹⁸F-FDG-PET/CT) carried out 3-6 months after (chemo)radiotherapy in head and neck squamous cell carcinoma.

MATERIALS AND METHODS

For this retrospective cohort study we included 82 patients with advanced-stage head and neck squamous cell carcinoma treated between 2012 and 2015. Primary tumours and lymph nodes were assessed separately. DWI was analysed qualitatively and quantitatively. ¹⁸F-FDG-PET/CT was evaluated using the Hopkins criteria. Dichotomous qualitative analysis was carried out for both modalities. Cox regression analysis was used for univariate analysis of recurrence-free survival (RFS). Significant univariate parameters were included in multivariate analysis.

RESULTS

In 12 patients, locoregional recurrence occurred. With all imaging strategies, either single-modality or multi-modality, a high negative predictive value (NPV) was achieved (94.3-100%). In response evaluation of the primary site, the preferred strategy is ¹⁸F-FDG-PET/CT only, which resulted in a sensitivity of 85.7%, specificity of 86.5%, positive predictive value (PPV) of 37.5% and NPV of 98.5%. For response evaluation of the neck, the best results were obtained with a sequential approach only including the second modality in positive reads of the first modality. It did not matter which modality was assessed first. This strategy for lymph node assessment resulted in a sensitivity, specificity, PPV and NPV of 83.3%, 95.6%, 62.5%, and 98.5%, respectively. After correction for received treatment and human papillomavirus status, primary tumour (P = 0.009) or lymph node (P < 0.001) Hopkins score ≥4 on ¹⁸F-FDG-PET/CT remained significant predictors of RFS.

CONCLUSION

For response evaluation of the primary tumour ¹⁸F-FDG-PET/CT only is the preferred strategy, whereas for the neck a sequential approach including both DWI and ¹⁸F-FDG-PET/CT resulted in the best diagnostic accuracy for follow-up after (chemo)radiotherapy. Qualitative analysis of ¹⁸F-FDG-PET/CT is a stronger predictor of RFS than DWI analysis.

ADC-histogram analysis in head and neck squamous cell carcinoma. Associations with different histopathological features including expression of EGFR, VEGF, HIF-1α, Her 2 and p53. A preliminary study

OBJECTIVE

Apparent diffusion coefficient (ADC) values derived from Diffusion-weighted images are able to reflect tumor microstructure, such as cellularity, extracellular matrix or proliferation potential. This present study sought to correlate prognostic relevant histopathologic parameters with ADC values derived from a whole lesion measurement in head and neck squamous cell carcinoma (HNSCC).

MATERIALS AND METHODS

Thirty-four patients with histological proven primary HNSCC were prospectively acquired. Histogram analysis was derived from ADC maps. In all cases, expression of Hif1-alpha, VEGF, EGFR, p53, p16, Her 2 were analyzed.

RESULTS

In the overall patient sample, ADCmax correlated with p53 expression (p = -0.446, p = 0.009) and ADCmode correlated with Her2-expression (p = -0.354, p = 0.047). In the p16 positive group there were several correlations. P25, P90 and entropy correlated with Hif1-alpha (p = -0.423, p = 0.05, p = -0.494, p = 0.019, p = 0.479, p = 0.024, respectively). Kurtosis correlated with P53 expression (p = -0.466, p = 0.029). For p16 negative carcinomas the following associations could be identified. Mode correlated with VEGF-expression (p = -0.657, p = 0.039). ADCmax, P75, P90, and Std correlated with p53-expression (p = -0.827, p = 0.002, p = -0.736, p = 0.01, p = -0.836, p = 0.001 and p = -0.70, p = 0.016, respectively). There were no statistically significant differences of ADC histogram parameters between p16 positive and p16 negative carcinomas.

CONCLUSION

ADC histogram values can reflect different histopathological features in HNSCC. Associations between ADC histogram analysis parameters and histopathology depend on p16 status.

Diffusion-Weighted Imaging in the Oral and Maxillofacial Region: Usefulness of Apparent Diffusion Coefficient Maps and Maximum Intensity Projection for Characterization of Normal Structures and Lesions

Background

The aim of this study was to investigate diffusion-weighted imaging (DWI) in the oral and maxillofacial region, with a special focus on the usefulness of apparent diffusion coefficient (ADC) maps and maximum intensity projection (MIP) for characterization of normal structures and lesions.

Material/Methods

Thirty-five patients who underwent magnetic resonance imaging (MRI) for diagnosis of oral and maxillofacial lesions were included in this prospective study. DWI was performed on a 1.5 T unit, with b factor of 0 and 800 s/mm²; moreover, ADC maps were generated. ADC values were measured for normal structures, odontogenic infections, squamous cell carcinomas (SCC), and hemangiomas.

Results

As regards the normal structures, the mean ADC value of the cerebrospinal fluid (3.65±0.60×10^–3 mm²/s) in the upper neck area was higher than that of the spinal cord (0.74±0.15×10^–3 mm²/s, P=0.000), lymph nodes (0.87±0.17×10^–3 mm²/s, P=0.000), and Waldeyer’s ring (0.92±0.29×10^–3 mm²/s, P=0.000). The mean ADC value of hemangiomas (1.52±0.31×10^–3 mm²/s) was higher than that of odontogenic infections (0.85±0.36×10^–3 mm²/s, P=0.034) and SCC (1.38±0.22×10^–3 mm²/s, P=0.840). Furthermore, MIP (DWI) showed the normal structures and lesions in the oral and maxillofacial region in an improved way.

Conclusions

DWI, ADC maps, and MIP can be used to characterize and differentiate normal structures and lesions in the oral and maxillofacial region.

The diagnostic role of diffusion-weighted magnetic resonance imaging in hypopharyngeal carcinoma

The aim of the present study was to assess the role of diffusion-weighted magnetic resonance imaging (DWI) and apparent diffusion coefficient (ADC) values in hypopharyngeal carcinoma. A total of 40 hypopharyngeal carcinoma tissues and 15 benign lesion tissues were retrospectively analyzed. DWI, and T1- and T2-weighted magnetic resonance imaging (MRI) was performed. The sensitivity, specificity and accuracy of conventional MRI were 97.5, 66.7, and 89.1%, respectively. The mean ADC value [diffusion sensitive factor (b)=1,000× sec/mm²) for hypopharyngeal carcinomas was (1.0285±0.0328)×10⁻³ mm²/sec, which was significantly lower than the mean ADC value for benign lesions [(1.5333±0.1061)×10⁻³ mm²/sec; P<0.001]. Receiver operating characteristic (ROC) curve analysis revealed that the area under the curve (AUC) was 0.921 while the optimal threshold for the cut-off point of the ADC was 1.075×10⁻³ mm²/sec. The mean ADC value of the metastatic nodes was (0.9184±0.0538)×10⁻³ mm²/sec, lower than the mean value for the benign nodes [(1.2538±0.1145)×10⁻³ mm²/sec; P=0.005]. Two groups were created according to the mean of the ADC value of hypopharyngeal carcinomas [≤(1.0285±0.0328)×10⁻³ mm²/sec vs. >(1.0285±0.0328)×10⁻³ mm²/sec]. The 2-year survival rates of the two groups were 55.6 and 100.0%, respectively (P=0.024). ADC values may aid in distinguishing hypopharyngeal carcinomas from benign lesions and differentiating metastatic lymph nodes of hypopharyngeal squamous cell carcinomas from reactive cervical lymph nodes. In conclusion, mean ADC values may be useful prognostic factors in univariate analysis of hypopharyngeal carcinoma.

Diffusion-weighted magnetic resonance imaging in oral and maxillofacial lesions: preliminary study on diagnostic ability of apparent diffusion coefficient maps

OBJECTIVES

The aim of this study was to investigate the usefulness of diffusion-weighted magnetic resonance imaging (DWI) in oral and maxillofacial lesions, especially the utility of apparent diffusion coefficient (ADC) maps for differential diagnosis of these lesions.

METHODS

Fifty-seven patients who underwent magnetic resonance imaging for diagnosis of oral and maxillofacial lesions were included in this prospective study. DWI was performed on a 1.5 T unit with b-factors of 0 and 800 s/mm², and ADC maps were generated. ADC values were measured for all 57 oral and maxillofacial lesions (19 squamous cell carcinoma, 10 medication-related osteonecrosis of the jaw, 6 odontogenic abscess, 4 ranula, 4 osteoradionecrosis, 4 hemangioma, 3 pleomorphic adenoma, 3 odontogenic keratocyst, 2 nasopalatine duct cyst, 1 malignant melanoma, and 1 basal cell carcinoma).

RESULTS

The mean ADC values for ranula (2.69 ± 0.59 × 10^-3 mm²/s) and nasopalatine duct cyst (2.34 ± 0.12 × 10^-3 mm²/s) were significantly higher than those for the other oral and maxillofacial lesions (p = 0.000). In contrast, the mean ADC value for odontogenic abscess (0.67 ± 0.36 × 10^-3 mm²/s) was significantly lower than those for the other oral and maxillofacial lesions (p = 0.000).

CONCLUSIONS

The present study suggests the usefulness of DWI in oral and maxillofacial lesions, especially the utility of ADC maps for differential diagnosis of these lesions.

Local recurrence of squamous cell carcinoma of the head and neck after radio(chemo)therapy: Diagnostic performance of FDG-PET/MRI with diffusion-weighted sequences

PURPOSE

To determine the diagnostic performance of FDG-PET/MRI with diffusion-weighted imaging (FDG-PET/DWIMRI) for detection and local staging of head and neck squamous cell carcinoma (HNSCC) after radio(chemo)therapy.

MATERIALS AND METHODS

This was a prospective study that included 74 consecutive patients with previous radio(chemo)therapy for HNSCC and in whom tumour recurrence or radiation-induced complications were suspected clinically. The patients underwent hybrid PET/MRI examinations with morphological MRI, DWI and FDG-PET. Experienced readers blinded to clinical/histopathological data evaluated images according to established diagnostic criteria taking into account the complementarity of multiparametric information. The standard of reference was histopathology with whole-organ sections and follow-up ≥24 months. Statistical analysis considered data clustering.

RESULTS

The proof of diagnosis was histology in 46/74 (62.2%) patients and follow-up (mean ± SD = 34 ± 8 months) in 28/74 (37.8%). Thirty-eight patients had 43 HNSCCs and 46 patients (10 with and 36 without tumours) had 62 benign lesions/complications. Sensitivity, specificity, and positive and negative predictive value of PET/DWIMRI were 97.4%, 91.7%, 92.5% and 97.1% per patient, and 93.0%, 93.5%, 90.9%, and 95.1% per lesion, respectively. Agreement between imaging-based and pathological T-stage was excellent (kappa = 0.84, p < 0.001).

CONCLUSION

FDG-PET/DWIMRI yields excellent results for detection and T-classification of HNSCC after radio(chemo)therapy.

KEY POINTS

• FDG-PET/DWIMRI yields excellent results for the detection of post-radio(chemo)therapy HNSCC recurrence. • Prospective one-centre study showed excellent agreement between imaging-based and pathological T-stage. • 97.5% of positive concordant MRI, DWI and FDG-PET results correspond to recurrence. • 87% of discordant MRI, DWI and FDG-PET results correspond to benign lesions. • Multiparametric FDG-PET/DWIMRI facilitates planning of salvage surgery in the irradiated neck.

Impact of 3T multiparametric MRI and FDG-PET-CT in the evaluation of occult primary cancer with cervical node metastasis

Background

This study aimed to determine the ability of multimodal evaluation with multiparametric 3T-MRI (MPMRI) and positron emission tomography - computed tomography (PET/CT) to detect cancer of unknown primary origin (CUP) with neck lymph node (LN) metastasis.

Methods

The study group comprised 38 retrospectively analysed consecutive patients with LN metastasis in the head and neck (HN) region without known primary tumours (PTs). Statistical values of 3T-MRI and of FDG-PET/CT scans were evaluated.

Results

Of the 38 CUPs, conventional native T1-, T2-weighted and STIR sequences detected 6 PTs. Native sequences plus diffusion-weighted imaging (DWI) found 14-, and with fat suppression contrast-enhanced T1-weighted measurement as well as with the complex MPMRI found 15 primaries and with PET/CT 17 CUPs could be evaluated, respectively. The detection rates were 15.8, 36.8, 39.5, 39.5 and 44.7 % for conventional native MRI, native plus DWI, native with contrast-enhanced MRI (CE-MRI), for MPMRI, and for PET/CT, respectively. The overall detection rate proved by histology was 47.4 %. PET/CT provided the highest sensitivity (Sv: 94.4 %) but a lower specificity (Sp: 65.0 %), using MPMRI (Sv: 88.2 %) the specificity increased to 71.4 %. DWIincreased specificity of the native sequences (Sp: 76.2 %). Conventional native sequences plus DWI as well as 3T-MPMRI and PET/CT were same accurate (Acc: 79.0 %) and had similar likelihood ratio (LR: 3.42, 3.03 and 2.62) in detecting unknown PT sites.

Conclusions

The accuracy of FDG-PET/CT and MPMRI in case of CUP in finding the primary cancer in the neck regions is identical. While using PET/CT whole body information can be obtained in one examination. MPMRI shows the local soft tissue status more accurately. In cases of CUP PET/CT should be the first method of choice if it is available. MPMRI can clarify the exact primary tumor stage, and it can be advantageous in clarifying the prognostic factors, which is necessary in case of advanced tumor stage and when surgery is under consideration. In case low N stage is likely after the clinical examination and wait and see policy can be considered, MPMRI is recommended, and in this case the significance the of radiation free MPMRI is increasing.

Electronic supplementary material

The online version of this article (doi:10.1186/s40644-016-0097-x) contains supplementary material, which is available to authorized users.

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.

Diffusion-weighted imaging in the head and neck region: usefulness of apparent diffusion coefficient values for characterization of lesions

PURPOSE

We aimed to evaluate the role of apparent diffusion coefficient (ADC) values calculated from diffusion-weighted imaging for head and neck lesion characterization in daily routine, in comparison with histopathological results.

METHODS

Ninety consecutive patients who underwent magnetic resonance imaging (MRI) at a university hospital for diagnosis of neck lesions were included in this prospective study. Diffusion-weighted echo-planar MRI was performed on a 1.5 T unit with b factor of 0 and 1000 s/mm2 and ADC maps were generated. ADC values were measured for benign and malignant whole lesions seen in daily practice.

RESULTS

The median ADC value of the malignant tumors and benign lesions were 0.72×10-3 mm2/s, (range, 0.39-1.51×10-3 mm2/s) and 1.17×10-3 mm2/s, (range, 0.52-2.38×10-3 mm2/s), respectively, with a significant difference between them (P < 0.001). A cutoff ADC value of 0.98×10-3 mm2/s was used to distinguish between benign and malignant lesions, yielding 85.3% sensitivity and 78.6% specificity. The median ADC value of lymphomas (0.44×10-3 mm2/s; range, 0.39-0.58×10-3 mm2/s) was significantly smaller (P < 0.001) than that of squamous cell carcinomas (median ADC value 0.72×10-3 mm2/s; range, 0.65-1.06×10-3 mm2/s). There was no significant difference between median ADC values of inflammatory (1.13×10-3 mm2/s; range, 0.85-2.38×10-3 mm2/s) and noninflammatory benign lesions (1.26×10-3 mm2/s; range, 0.52-2.33×10-3 mm2/s).

CONCLUSION

Diffusion-weighted imaging and the ADC values can be used to differentiate and characterize benign and malignant head and neck lesions.

Differentiation of benign and malignant lesions of the tongue by using diffusion-weighted MRI at 3.0 T

OBJECTIVES

Diffusion-weighted MRI (DWI) has been introduced in head and neck lesions and adds important information to the findings obtained through conventional MRI. The purpose of this study was to assess the role of DWI in differentiating benign and malignant lesions of the tongue at 3.0-T field strength imaging.

METHODS

78 patients with 78 lingual lesions underwent conventional MRI and DWI with b-values of 0 and 1000 s mm(-2) before therapy. The apparent diffusion coefficient (ADC) maps were reconstructed, and the ADC values of the lingual lesions were calculated and compared between benign and malignant lesions of the tongue.

RESULTS

The mean ADC values of the malignant tumours, benign solid lesions and cystic lesions were (1.08±0.16)×10(-3), (1.68±0.33)×10(-3) and (2.21±0.35)×10(-3) mm2 s(-1), respectively. The mean ADC values of malignant tumours were significantly lower (p<0.001) than those of benign solid lesions, and the mean ADC values of benign solid lesions were significantly lower (p<0.001) than those of cystic lesions. Receiver operating characteristic analysis showed that when an ADC value<.31×10(-3) mm2 s(-1) was used for predicting malignancy, the highest accuracy of 95.3%, sensitivity of 92.6% and specificity of 97.3% were obtained.

CONCLUSIONS

ADC values of benign and malignant lesions are significantly different at 3.0-T imaging. DWI can be applied as a complementary tool in the differentiation of benign and malignant lesions of the tongue.