Is there a correlation between 18F-FDG-PET standardized uptake value, T-classification, histological grading and the anatomic subsites in newly diagnosed squamous cell carcinoma of the head and neck?

Biomechanical imaging biomarker during chemoradiotherapy predicts treatment response in head and neck squamous cell carcinoma

Objective. For response-adapted adaptive radiotherapy (R-ART), promising biomarkers are needed to predict post-radiotherapy (post-RT) responses using routine clinical information obtained during RT. In this study, a patient-specific biomechanical model (BM) of the head and neck squamous cell carcinoma (HNSCC) was proposed using the pre-RT maximum standardized uptake value (SUVmax) of18F-fluorodeoxyglucose (FDG) and tumor structural changes during RT as evaluated using computed tomography (CT). In addition, we evaluated the predictive performance of BM-driven imaging biomarkers for the treatment response of patients with HNSCC who underwent concurrent chemoradiotherapy (CCRT).Approach. Patients with histologically confirmed HNSCC treated with definitive CCRT were enrolled in this study. All patients underwent CT two times as follows: before the start of RT (pre-RT) and 3 weeks after the start of RT (mid-RT). Among these patients, 67 patients who underwent positron emission tomography/CT during the pre-RT period were included in the final analysis. The locoregional control (LC), progression-free survival (PFS), and overall survival (OS) prediction performances of whole tumor stress change (TS) between pre- and mid-RT computed using BM were assessed using univariate, multivariate, and Kaplan-Meier survival curve analyses, respectively. Furthermore, performance was compared with the pre and post-RT SUVmax, tumor volume reduction rate (TVRR) during RT, and other clinical prognostic factors.Main results. For both univariate, multivariate, and survival curve analyses, the significant prognostic factors were as follows (p< 0.05): TS and TVRR for LC; TS and pre-RT FDG-SUVmaxfor PFS; and TS only for OS. In addition, for 2 year LC, PFS, and OS prediction, TS showed a comparable predictive performance to post-RT FDG-SUVmax.Significance. BM-driven TS is an effective prognostic factor for tumor treatment response after CCRT. The proposed method can be a feasible functional imaging biomarker that can be acquired during RT using only routine clinical data and may provide useful information for decision-making during R-ART.

FDG PET/CT and Endoscopic Ultrasound for Preoperative T-Staging of Esophageal Squamous Cell Carcinoma

This study aimed to compare the diagnostic performances of endoscopic ultrasound (EUS) and FDG PET/CT in the preoperative T-staging of esophageal squamous cell carcinoma (ESCC) and determine whether their innovative coordination achieves better prediction. In total, 100 patients diagnosed with ESCC, 57 without (CRT[-]sub) and 43 with (CRT[+]sub) neoadjuvant chemoradiotherapy, undergoing EUS and FDG PET/CT, followed by surgical resection of the tumor, were included in this analysis. EUS classified T-stages based on the depth of primary tumor invasion, and FDG PET/CT used thresholded maximal standardized uptake value (SUVmax) classifications. By employing pathology results as the reference standard, we assessed the accuracy of EUS and FDG PET/CT, evaluated their concordance using the κ statistic, and conducted a comparative analysis between the two modalities through McNemar's chi-square test. FDG PET/CT had higher overall accuracy than EUS (for CRT[-]sub: 71.9%, κ = 0.56 vs. 56.1%, κ = 0.31, p = 0.06; for CRT[+]sub: 65.1%, κ = 0.50 vs. 18.6%, κ = 0.05, p < 0.01) in predicting pT- and ypT-stage. Our proposed method of incorporating both FDG PET/CT and EUS information could achieve higher accuracies in differentiating between early and locally advanced disease in the CRT[-]sub group (82.5%) and determining residual viable tumor in the CRT[+]sub group (83.7%) than FDG PET/CT or EUS alone. FDG PET/CT had a better diagnostic ability than EUS to predict the (y)pT-stage of ESCC. Our complementary method, which combines the advantages of both imaging modalities, can deliver higher accuracy for clinical applications of ESCC.

Relationships Between DCE-MRI, DWI, and 18F-FDG PET/CT Parameters with Tumor Grade and Stage in Patients with Head and Neck Squamous Cell Carcinoma

Objectives

Properties of head and neck squamous cell carcinoma (HNSCC) such as cellularity, vascularity, and glucose metabolism interact with each other. This study aimed to investigate the associations between diffusion-weighted imaging (DWI), dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI), and positron emission tomography/computed tomography (PET/CT) in patients with HNSCC.

Methods

Fourteen patients who were diagnosed with HNSCC were investigated using DCE-MRI, DCE, and ¹⁸fluoride-fluorodeoxyglucose PET/CT and evaluated retrospectively. Ktrans, Kep, Ve, and initial area under the curve (iAUC) parameters from DCE-MRI, ADC_max, ADC_mean, and ADCmin parameters from DWI, and maximum standardized uptake value (SUV_max), SUV_mean, metabolic tumor volume (MTV), and total lesion glycolysis (TLG) parameters from PET were obtained. Spearman's correlation coefficient was used to analyze associations between these parameters. In addition, these parameters were grouped according to tumor grade and T and N stages, and the difference between the groups was evaluated using the Mann-Whitney U test.

Results

Correlations at varying degrees were observed in the parameters investigated. ADC_mean moderately correlated with Ve (p=0.035; r=0.566). Ktrans inversely correlated with SUV_max (p=0.017; r=-0.626). iAUC inversely correlated with SUV_max, SUV_mean, TLG, and MTV (p<0.05, r≤-0.700). MTV (40% threshold) was significantly higher in T4 tumors than in T1-3 tumors (p=0.020). No significant difference was found in the grouping made according to tumor grade and N stage in terms of these parameters.

Conclusion

Tumor cellularity, vascular permeability, and glucose metabolism had significant correlations at different degrees. Furthermore, MTV may be useful in predicting T4 tumors.

FDG-PET-CT/MRI in head and neck squamous cell carcinoma: Impact on pretherapeutic N classification, detection of distant metastases, and second primary tumors

BACKGROUND

To assess the effect of 18-fluorodeoxyglucose positron emission tomography (FDG-PET) in the pretherapeutic staging of N classification, detection rate of distant metastases, and second primaries.

METHODS

Retrospective study on patients with head and neck carcinoma. We compared pretherapeutic N classification by ultrasound, computed tomography (CT)/magnetic resonance imaging (MRI), and FDG-PET-CT/MRI.

RESULTS

A change in the N classification due to FDG-PET-CT/MRI was observed in 116 patients (39.5%) compared to N classification by ultrasound and fine-needle aspiration cytology. Patients with advanced nodal classification (>N2a) were more likely to be reclassified. Distant metastases were detected in 19 patients and a total of 36 second primaries were diagnosed by FDG-PET-CT/MRI. Detection of distant metastases was more likely in regional advanced disease (>N2a). Smokers (>10 py) had a significantly higher risk of second primary.

CONCLUSION

FDG-PET-CT/MRI leads to a significant change in pretherapeutic N classification. The cumulative incidence of distant metastases and second primaries was 18.7%.

Application of integrated positron emission tomography/magnetic resonance imaging in evaluating the prognostic factors of head and neck squamous cell carcinoma with positron emission tomography, diffusion-weighted imaging, dynamic contrast enhancement and combined model

OBJECTIVES

This study was designed to investigate the distribution of the independent parameters of PET and MR in tumour differentiation and staging and to evaluate the diagnostic efficiency of the independent parameters and combined model of PET/MR in the tumour differentiation of head and neck squamous cell carcinoma (HNSCC).

METHODS

The patients with the preliminary diagnosis of HNSCC were included and underwent the integrated PET/MR The parameters included the diffusion-weighted imaging, dynamic contrast enhancement and PET. The correlations between different parameters and the distribution in groups of tumour differentiation and staging were analysed. The combined model was established with complementary PET/MR parameters. The diagnostic efficiency of the independent parameters and combined model in the tumour differentiation were analysed by receiver operating characteristic curve.

RESULTS

The correlations between the parameters of dynamic contrast enhancement and PET were most significant. There were significant differences between the well-differentiated group and the moderately/poorly differentiated group in terms of the mean values of apparent diffusion coefficient (ADC) and standardised uptake value (SUV) (p < 0.05). The distributions among different tumour stage groups were not statistically different in all the parameters. The diagnostic efficiency of tumour differentiation increased in the order of K_epmean, SUVmean, ADCmean, and the combined model.

CONCLUSIONS

Compared with the independent parameter, the combination of multiple parameters with PET/MR can further improve the diagnostic performance of tumour differentiation in HNSCC.

Associations Between [18F]FDG-PET and Complex Histopathological Parameters Including Tumor Cell Count and Expression of KI 67, EGFR, VEGF, HIF-1α, and p53 in Head and Neck Squamous Cell Carcinoma

PURPOSE

Head and neck squamous cell carcinoma (HNSCC) is one of common cancers worldwide. Positron emission tomography (PET) with 2-deoxy-2-[¹⁸F]fluoro-D-glucose ([¹⁸F]FDG) is increasingly used for diagnosing and staging, as well as for monitoring of treatment of HNSCC. PET parameters like maximum and mean standard uptake values (SUV_max, SUV_mean) can predict the behavior of HNSCC. The purpose of this study was to analyze possible associations between these PET parameters and clinically relevant histopathological features in patients with HNSCC.

PROCEDURES

Overall, 22 patients, mean age, 55.2 ± 11.0 years, with different HNSCC were acquired. Low grade (G1/2) tumors were diagnosed in 10 cases (45 %) and high grade (G3) tumor in 12 (55 %) patients. In all cases, whole body PET was performed. For this study, the following specimen stainings were performed: MIB-1 staining (KI 67 expression), epidermal growth factor receptor (EGFR), vascular endothelial growth factor (VEGF), tumor suppressor protein p53, hypoxia-inducible factor (HIF)-1α, and human papilloma virus (p16 expression). All stained specimens were digitalized and analyzed by using the ImageJ software 1.48v. Spearman's correlation coefficient (ρ) was used to analyze associations between investigated parameters. P values <0.05 were taken to indicate statistical significance.

RESULTS

P16-negative tumors showed statistically significant higher SUV_max (ρ = 0.006) and SUV_mean values (ρ = 0.002) in comparison to p16-positive carcinomas. No significant differences were identified in the analyzed parameters between poorly and moderately/well-differentiated tumors. In overall sample, there were no statistically significant correlations between the [¹⁸F]FDG-PET and histopathological parameters. Also, in G1/2 tumors, no significant correlations were identified. In G3 carcinomas, cell count correlated statistical significant with SUV_max (p = 0.580, P = 0.048) and SUV_mean (ρ = 0.587, P = 0.045).

CONCLUSION

Associations between [¹⁸F]FDG-PET parameters and different histopathological features in HNSCC depend significantly on tumor grading. In G1/2 carcinomas, there were no significant correlations between [¹⁸F]FDG-PET parameters and histopathology. In G3 lesions, SUV_max and SUV_mean reflect tumor cellularity.

18F-FDG-PET Can Predict Microvessel Density in Head and Neck Squamous Cell Carcinoma

Aim: Positron emission tomography (PET) with ¹⁸F-fluordeoxyglucose (¹⁸F-FDG) plays an essential role in the staging and tumor monitoring of head and neck squamous cell carcinoma (HNSCC). Microvessel density (MVD) is one of the clinically important histopathological features in HNSCC. The purpose of this study was to analyze possible associations between ¹⁸F-FDG-PET findings and MVD parameters in HNSCC. Materials and Methods: Overall, 22 patients with a mean age of 55.2 ± 11.0 and with different HNSCC were acquired. In all cases, whole-body ¹⁸F-FDG-PET was performed. For each tumor, the maximum and mean standardized uptake values (SUV_max; SUV_mean) were determined. The MVD, including stained vessel area and total number of vessels, was estimated on CD105 stained specimens. All specimens were digitalized and analyzed by using ImageJ software 1.48v. Spearman's correlation coefficient (r) was used to analyze associations between investigated parameters. p-values of <0.05 were taken to indicate statistical significance. Results: SUV_max correlated with vessel area (r = 0.532, p = 0.011) and vessel count (r = 0.434, p = 0.043). Receiver operating characteristic analysis identified a threshold SUV_max of 15 to predict tumors with high MVD with a sensitivity of 72.7% and specificity of 81.8%, with an area under the curve of 82.6%. Conclusion: ⁸F-FDG-PET parameters correlate statistically significantly with MVD in HNSCC. SUV_max may be used for discrimination of tumors with high tumor-related MVD.

Interobserver variability of image-derived arterial blood SUV in whole-body FDG PET

Background

Today, the standardized uptake value (SUV) is essentially the only means for quantitative evaluation of static [¹⁸F-]fluorodeoxyglucose (FDG) positron emission tomography (PET) investigations. However, the SUV approach has several well-known shortcomings which adversely affect the reliability of the SUV as a surrogate of the metabolic rate of glucose consumption. The standard uptake ratio (SUR), i.e., the uptake time-corrected ratio of tumor SUV to image-derived arterial blood SUV, has been shown in the first clinical studies to overcome most of these shortcomings, to decrease test-retest variability, and to increase the prognostic value in comparison to SUV. However, it is unclear, to what extent the SUR approach is vulnerable to observer variability of the additionally required blood SUV (BSUV) determination. The goal of the present work was the investigation of the interobserver variability of image-derived BSUV.

Methods

FDG PET/CT scans from 83 patients (72 male, 11 female) with non-small cell lung cancer (N = 46) or head and neck cancer (N = 37) were included. BSUV was determined by 8 individuals, each applying a dedicated delineation tool for the BSUV determination in the aorta. Two of the observers applied two further tools. Altogether, five different delineation tools were used. With each used tool, delineation was performed for the whole patient group, resulting in 12 distinct observations per patient. Intersubject variability of BSUV determination was assessed using the fractional deviations for the individual patients from the patient group average and was quantified as standard deviation (SD _is), 95% confidence interval, and range.

Interobserver variability of BSUV determination was assessed using the fractional deviations of the individual observers from the observer-average for the considered patient and quantified as standard deviations (SD _p, SD _d) or root mean square (RMS), 95% confidence interval, and range in each patient, each observer, and the pooled data respectively.

Results

Interobserver variability in the pooled data amounts to RMS = 2.8% and is much smaller than the intersubject variability of BSUV (SD _is= 16%). Averaged over the whole patient group, deviations of individual observers from the observer average are very small and fall in the range [ − 0.96, 1.05]%. However, interobserver variability partly differs distinctly for different patients, covering a range of [0.7, 7.4]% in the investigated patient group.

Conclusion

The present investigation demonstrates that the image-based manual determination of BSUV in the aorta is sufficiently reproducible across different observers and delineation tools which is a prerequisite for accurate SUR determination. This finding is in line with the already demonstrated superior prognostic value of SUR in comparison to SUV in the first clinical studies.

[18F]Fluorodeoxyglucose uptake by positron emission tomography predicts outcomes for oropharyngeal and hypopharyngeal cancer treated with definitive radiotherapy

This study evaluated the prognostic significance of the maximum standardized uptake value of the primary site (pSUVmax) in 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) scans of patients with oropharyngeal or hypopharyngeal cancer who were treated using definitive radiotherapy. The study included 86 patients who were primarily treated with radiotherapy for oropharyngeal or hypopharyngeal cancer. Sixty-nine patients underwent concurrent chemotherapy. The associations between pre-treatment pSUVmax and treatment outcomes were evaluated. The most appropriate pSUVmax cut-off value for predicting disease-free survival (DFS) and local control (LC) was selected using receiver operating characteristic (ROC) curves. The median follow-up time for surviving patients was 60 months, while the median survival time in the entire patient cohort was 55 months. A pSUVmax cut-off value of 9.0 showed the best discriminative performance. Five-year OS and DFS rates were 65.9% and 60.0%, respectively. In univariate analyses, pSUVmax (p = 0.009), T-stage (p = 0.001), N-stage (p = 0.039), and clinical stage (p = 0.017) were identified as significant prognostic predictors for DFS. The multivariate analysis did not identify any statistically significant factors, but the association between pSUVmax and DFS was borderline significant (p = 0.055). Interestingly, pSUVmax was predictive of local controllability in T1–T2 disease (p = 0.024), but there was no significant association for T3–T4 disease (p = 0.735). In this study, pSUVmax was predictive of DFS and LC in patients with oropharyngeal or hypopharyngeal cancer that was treated with definitive radiotherapy. pSUVmax was strongly associated with LC in T1–T2 disease.

Combined Metabolo-Volumetric Parameters of 18F-FDG-PET and MRI Can Predict Tumor Cellularity, Ki67 Level and Expression of HIF 1alpha in Head and Neck Squamous Cell Carcinoma: A Pilot Study

BACKGROUND: Our purpose was to evaluate associations of combined ¹⁸F-FDG-PET and MRI parameters with histopathological features in head and neck squamous cell carcinoma (HNSCC). METHODS: Overall, 22 patients with HNSCC were acquired (10 with G1/2 tumors and 12 with G3 tumors).¹⁸F-FDG-PET/CT and MRI was performed and maximum standardized uptake value (SUV_max), total lesion glycolysis (TLG) and metabolic tumor volume (MTV) were estimated. Neck MRI was obtained on a 3 T scanner. Diffusion weighted imaging was performed with estimation of apparent diffusion coefficient (ADC). Perfusion parameters K_trans,V_e, and K_ep were derived from dynamic contrast-enhanced (DCE) imaging. Different combined PET/MRI parameters were calculated as ratios: PET parameters divided by ADC or DCE MRI parameters. The following histopathological features were estimated: Ki 67, EGFR, VEGF, p53, hypoxia-inducible factor (HIF)-1α, and cell count. Spearman's correlation coefficient (p) was used for correlation analysis. P < .05 was taken to indicate statistical significance. RESULTS: In overall sample, cellularity correlated with SUV_max/ADC_min (P = .558, P = .007), TLG/ADC_min (P = .546, P = .009), and MTV/ADC_min (P = .468, P = .028). MTV/K_ep correlated with expression of HIF-1α (P = .450, P = 0,047). In G1/2 tumors, SUV_max/ADC_min correlated with HIF-1α (P = −.648, P = .043); MTV/K_ep (P = −.669, P = .034) and TLG/K_ep (P = −.644, P = .044) with Ki67. In G3 tumors, cellularity correlated with SUV_max/ADC_min (P = .832, P = .001), SUV_max/ADC_mean (P = .741, P = .006), and TLG/ADC_min (P = .678, P = .015). MTV/ADC_min and TLG/ADC_min tended to correlate with HIF-1α. CONCLUSION: Combined parameters of ¹⁸F-FDG-PET and MRI can reflect Ki 67, tumor cellularity and expression of HIF-1α in HNSCC. Associations between parameters of ¹⁸F-FDG-PET and MRI and histopathology depend on tumor grading.

The value of whole-body contrast-enhanced 18F-FDG PET/CT imaging in the diagnosis and staging of patients with laryngeal carcinoma

PURPOSE

This study aimed to determine whether intravenous contrast-enhanced dual-phase fluorine-18--fluorodeoxyglucose (F-FDG) PET/CT scans provide additional diagnostic information compared with the MRI/CT in patients with laryngeal carcinoma during the initial staging.

PATIENTS AND METHODS

Forty-five consecutive patients (44 men, one woman; mean age±SD, 67.0±9.0 years, range: 45-80 years) with carcinoma of the larynx who had MRI/CT and intravenous contrast-enhanced PET/CT were enrolled. Each patient was scanned on the PET/CT system 1 h (early) and 2 h (delayed) after injection. The maximum standardized uptake values of the primary tumor, nodal, and distant metastatic lesions were measured using the dual-time-point method. Double-blinded F-FDG PET/CT and MRI/CT staging data were compared. The diagnostic accuracy of each modality was compared for primary tumors, nodal metastasis, and the tumor staging.

RESULTS

For primary tumor detection, the sensitivity of PET/CT was higher (100%) than MRI/CT (93.3%). The accuracy for N status was 88.8% for PET/CT, being superior to MRI, which had an accuracy of 66.6%. The sensitivity and specificity for the detection of nodal metastasis were 100 and 84.6% for PET/CT compared with 100 and 50% for MRI/CT, respectively. As an initial TNM-staging method, the PET/CT had a diagnostic accuracy of 86.6% compared with 44.4% for MRI/CT.

CONCLUSION

The results suggest that contrast-enhanced dual-phase PET/CT imaging contributes additional diagnostic information compared with the conventional methods for the initial evaluation of primary laryngeal tumors. F-FDG PET/CT has a good diagnostic performance for the detection of regional nodal and distant metastasis, and also synchronous tumors in patients with laryngeal carcinoma.

Correlation of Positron Emission Tomography/Computed Tomography Scan with Smoking, Tumor Size, Stage and Differentiation in Head and Neck Cancer Patients

The goal of this study was to identify associations between positron emission tomography/computed tomography (PET/CT) maximum standardized uptake value (SUVmax) in patients presenting with head and neck squamous cell carcinoma (SCC) with tumor site, size, histologic differentiation, smoking, and diabetes. Charts of patients with oropharyngeal and laryngeal SCC who underwent ¹⁸F-fluorodeoxyglucose PET/CT scans were reviewed between May 2007 and August 2013. Statistical analyses included modeling log-transformed SUVmax values by tumor site, size, histologic differentiation, smoking status, and diabetes using unadjusted linear regressions. Differences were considered statistically significant for P< 0.05. A total of 111 patients (54 with oropharynx and 57 with larynx cancers) were included, 83 men and 28 women with an average age of 57.5 years old. There was a significantly higher pack-year smoking history (P = 0.005) in the larynx cancer group. While tumor T-stage was found to be significantly different (P < 0.0001), there was no difference in tumor size between the two groups: 3.16 cm and 3.58 cm in the oropharynx and larynx, respectively (P = 0.55). In the oropharynx cohort, SUVmax was associated with both tumor size (P = 0.0001) and stage (P < 0.0002). Interestingly, SUVmax differed by tumor differentiation in the larynx (P = 0.04) but not the oropharynx (P = 0.71). Finally, there was no significant difference in SUVmax relative to diabetes and smoking status. PET/CT SUVmax correlated with both tumor size and stage in oropharyngeal cancer patients, and it correlated only with tumor differentiation but not the size or stage in the larynx. There were no significant differences in SUVmax by diabetes or smoking status.

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.

Diffusion-weighted and PET/MR Imaging after Radiation Therapy for Malignant Head and Neck Tumors

Interpreting imaging studies of the irradiated neck constitutes a challenge because of radiation therapy-induced tissue alterations, the variable appearances of recurrent tumors, and functional and metabolic phenomena that mimic disease. Therefore, morphologic magnetic resonance (MR) imaging, diffusion-weighted (DW) imaging, positron emission tomography with computed tomography (PET/CT), and software fusion of PET and MR imaging data sets are increasingly used to facilitate diagnosis in clinical practice. Because MR imaging and PET often yield complementary information, PET/MR imaging holds promise to facilitate differentiation of tumor recurrence from radiation therapy-induced changes and complications. This review focuses on clinical applications of DW and PET/MR imaging in the irradiated neck and discusses the added value of multiparametric imaging to solve diagnostic dilemmas. Radiologists should understand key features of radiation therapy-induced tissue alterations and potential complications seen at DW and PET/MR imaging, including edema, fibrosis, scar tissue, soft-tissue necrosis, bone and cartilage necrosis, cranial nerve palsy, and radiation therapy-induced arteriosclerosis, brain necrosis, and thyroid disorders. DW and PET/MR imaging also play a complementary role in detection of residual and recurrent disease. Interpretation pitfalls due to technical, functional, and metabolic phenomena should be recognized and avoided. Familiarity with DW and PET/MR imaging features of expected findings, potential complications, and treatment failure after radiation therapy increases diagnostic confidence when interpreting images of the irradiated neck. Online supplemental material is available for this article.

Asphericity of pretherapeutic tumour FDG uptake provides independent prognostic value in head-and-neck cancer

OBJECTIVE

To propose a novel measure, namely the 'asphericity' (ASP), of spatial irregularity of FDG uptake in the primary tumour as a prognostic marker in head-and-neck cancer.

METHODS

PET/CT was performed in 52 patients (first presentation, n = 36; recurrence, n = 16). The primary tumour was segmented based on thresholding at the volume-reproducible intensity threshold after subtraction of the local background. ASP was used to characterise the deviation of the tumour's shape from sphere symmetry. Tumour stage, tumour localisation, lymph node metastases, distant metastases, SUVmax, SUVmean, metabolic tumour volume (MTV) and total lesion glycolysis (TLG) were also considered. The association of overall (OAS) and progression-free survival (PFS) with these parameters was analysed.

RESULTS

Cox regression revealed high SUVmax [hazard ratio (HR) = 4.4/7.4], MTV (HR = 4.6/5.7), TLG (HR = 4.8/8.9) and ASP (HR = 7.8/7.4) as significant predictors with respect to PFS/OAS in case of first tumour manifestation. The combination of high MTV and ASP showed very high HRs of 22.7 for PFS and 13.2 for OAS. In case of recurrence, MTV (HR = 3.7) and the combination of MTV/ASP (HR = 4.2) were significant predictors of PFS.

CONCLUSIONS

ASP of pretherapeutic FDG uptake in the primary tumour improves the prediction of tumour progression in head-and-neck cancer at first tumour presentation.

KEY POINTS

Asphericity (ASP) characterises the spatial heterogeneity of FDG uptake in tumours. ASP is a promising prognostic parameter in head-and-neck cancer. ASP is useful for identification of high-risk patients with head-and-neck cancer.

Prognostic value of tumour blood flow, [¹⁸F]EF5 and [¹⁸F]FDG PET/CT imaging in patients with head and neck cancer treated with radiochemotherapy

PURPOSE

In order to improve the treatment of squamous cell carcinoma of the head and neck, precise information on the treated tumour's biology is required and the prognostic importance of different biological parameters needs to be determined. The aim of our study was to determine the predictive value of pretreatment PET/CT imaging using [(18)F]FDG, a new hypoxia tracer [(18)F]EF5 and the perfusion tracer [(15)O]H₂O in patients with squamous cell cancer of the head and neck treated with radiochemotherapy.

METHODS

The study group comprised 22 patients with confirmed squamous cell carcinoma of the head and neck who underwent a PET/CT scan using the above tracers before any treatment. Patients were later treated with a combination of radiochemotherapy and surgery. Parametric blood flow was calculated from dynamic [(15)O]H₂O PET images using a one-tissue compartment model. [(18)F]FDG images were analysed by calculating standardized uptake values (SUV) and metabolically active tumour volumes (MATV). [(18)F]EF5 images were analysed by calculating tumour-to-muscle uptake ratios (T/M ratio). A T/M ratio of 1.5 was considered a significant threshold and used to determine tumour hypoxic subvolumes (HS) and hypoxic fraction area. The findings were finally correlated with the pretreatment clinical findings (overall stage and TNM stage) as well as the outcome following radiochemotherapy in terms of local control and overall patient survival.

RESULTS

Tumour stage and T-classification did not show any significant differences in comparison to the patients' metabolic and functional characteristics measured on PET. Using the Cox proportional hazards model, a shorter overall survival was associated with MATV (p = 0.008, HR = 1.108), maximum [(18)F]EF5 T/M ratio (p = 0.0145, HR = 4.084) and tumour HS (p = 0.0047, HR = 1.112). None of the PET parameters showed a significant effect on patient survival in the log-rank test, although [(18)F]EF5 maximum T/M ratio was the closest (p = 0.109). By contrast, tumour blood flow was not correlated with any of the clinical endpoints. There were no statistically significant correlations among [(18)F]FDG SUVmax, [(18)F]EF5 T/M ratio and blood flow.

CONCLUSION

Our study in a limited number of patients confirmed the importance of MATV in the prognosis of locally advanced squamous cell carcinoma of the head and neck. It is of interest that high uptake of the hypoxia tracer [(18)F]EF5 showed a stronger correlation with a poor clinical outcome than [(18)F]FDG uptake. This confirms the importance of hypoxia in treatment outcome and suggests that [(18)F]EF5 may act as a surrogate marker of radioresistance.

Functional imaging of head and neck squamous cell carcinoma with diffusion-weighted MRI and FDG PET/CT: quantitative analysis of ADC and SUV

Purpose

Head and neck squamous cell carcinoma (HNSCC) may cause a decreased apparent diffusion coefficient (ADC) on diffusion-weighted magnetic resonance imaging (DW MRI) and an increased standardized uptake value (SUV) on fluorodeoxyglucose (FDG) positron emission tomography (PET/CT). We analysed the reproducibility of ADC and SUV measurements in HNSCC and evaluated whether these biomarkers are correlated or independent.

Methods

This retrospective analysis of DW MRI and FDG PET/CT data series included 34 HNSCC in 33 consecutive patients. Two experienced readers measured tumour ADC and SUV values independently. Statistical comparison and correlation with histopathology was done. Intra- and inter-observer agreement for ADC and SUV measurements was assessed.

Results

Intraclass correlation coefficient (ICC) analysis showed almost perfect reproducibility (>0.90) for ADC_mean, ADC_min, SUV_max and SUV_mean values for intra-observer and inter-observer agreement. Mean ADC_mean and ADC_min in HNSCC were 1.05 ± 0.34 × 10⁻³ mm²/s and 0.65 ± 0.29 × 10⁻³ mm²/s, respectively. Mean SUV_mean and mean SUV_max were 7.61 ± 3.87 and 12.8 ± 5.0, respectively. Although statistically not significant, a trend towards higher SUV and lower ADC was observed with increasing tumour dedifferentiation. Pearson’s correlation analysis showed no significant correlation between ADC and SUV measurements (r −0.103, −0.051; p 0.552, 0.777).

Conclusion

Our data suggest that ADC and SUV values are reproducible and independent biomarkers in HNSCC.

Functional imaging of head and neck squamous cell carcinoma with diffusion-weighted MRI and FDG PET/CT: quantitative analysis of ADC and SUV

PURPOSE

Head and neck squamous cell carcinoma (HNSCC) may cause a decreased apparent diffusion coefficient (ADC) on diffusion-weighted magnetic resonance imaging (DW MRI) and an increased standardized uptake value (SUV) on fluorodeoxyglucose (FDG) positron emission tomography (PET/CT). We analysed the reproducibility of ADC and SUV measurements in HNSCC and evaluated whether these biomarkers are correlated or independent.

METHODS

This retrospective analysis of DW MRI and FDG PET/CT data series included 34 HNSCC in 33 consecutive patients. Two experienced readers measured tumour ADC and SUV values independently. Statistical comparison and correlation with histopathology was done. Intra- and inter-observer agreement for ADC and SUV measurements was assessed.

RESULTS

Intraclass correlation coefficient (ICC) analysis showed almost perfect reproducibility (>0.90) for ADCmean, ADCmin, SUVmax and SUVmean values for intra-observer and inter-observer agreement. Mean ADCmean and ADCmin in HNSCC were 1.05 ± 0.34 × 10(-3) mm(2)/s and 0.65 ± 0.29 × 10(-3) mm(2)/s, respectively. Mean SUVmean and mean SUVmax were 7.61 ± 3.87 and 12.8 ± 5.0, respectively. Although statistically not significant, a trend towards higher SUV and lower ADC was observed with increasing tumour dedifferentiation. Pearson's correlation analysis showed no significant correlation between ADC and SUV measurements (r -0.103, -0.051; p 0.552, 0.777).

CONCLUSION

Our data suggest that ADC and SUV values are reproducible and independent biomarkers in HNSCC.

18F-FDG-PET/CT for the assessment of the contralateral neck in patients with head and neck squamous cell carcinoma

OBJECTIVES/HYPOTHESIS

The aim was to compare the value of 18-Fluoro-Deoxyglucose (18F-FDG) positron emission tomography (PET)/computed tomography (CT) regarding contralateral lymph node (LN) metastasis in the neck.

STUDY DESIGN

Retrospective analysis of 61 patients staged by 18F-FDG-PET/CT.

METHODS

Cytology/histology served as a reference standard. Further, metabolic midline invasion (MI) of the primary tumor and the presence of bilateral LN metastases were assessed.

RESULTS

A true positive rate in the ipsilateral neck of 80% versus 65% in the contralateral neck was found (P = 0.067). Median-standardized uptake value (SUV)-max for suspicious LN ipsilaterally was 7.6 versus 5.8 contralaterally (P = 0.038). There was no positive correlation between metabolic MI and bilateral metastasis (P = 0.82).

CONCLUSIONS

The rate of true positive detected LN by 18F-FDG-PET/CT is less on the contralateral neck side; therefore, all suspicious LNs should be verified by cytology. A high SUV in the contralateral neck suggests metastatic disease regardless of nodal size. Metabolic MI needs to be addressed carefully as it was not predictive for bilateral LN involvement.

LEVEL OF EVIDENCE

4.

¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography as an effective diagnostic workup in cervical metastasis of carcinoma from an unknown primary tumor

PURPOSE

The purpose of this study is to assess the potential of ¹⁸F-fluorodeoxyglucose (¹⁸FDG) positron emission tomography/computed tomography (PET/CT) imaging for the diagnosis of cervical metastasis of carcinoma of an unknown primary tumor (CUP) and to determine whether the maximum standardized uptake value (SUV(max)) is a prognostic factor.

METHODS

Twenty-five consecutive patients with cervical metastasis of CUP were retrospectively analyzed by PET/CT between July 2007 and July 2011.

RESULTS

FDG PET/CT suggested a primary tumor in 21 out of 25 patients (84.0%). The sensitivity of FDG PET/CT in detecting the primary tumor was 73.3% (11 of 15), and the positive predictive value was 52.4% (11 of 21). The median follow-up duration of survival patients was 10.4 months (range: 0-30 months). The estimated 2-year overall survival rate of all patients was 50.0%. Univariate analyses did not reveal a significant difference in overall survival between the group of 11 patients identified by pathology and the 14 patients not identified by pathology (overall survival was 57.1% and 49.1%, respectively; p=0.468). The median SUV(max) was 7.6. In the log-rank test, patients with a low SUV(max) (≤ 7.0) in cervical lymph nodes had a significantly higher survival rate at 2 years (87.5% vs. 21.2%; p=0.007) than patients with a high SUV(max) (>7.0).

CONCLUSIONS

Although our study was inconclusive due to the small sample size, our results suggest that FDG PET/CT may be an effective diagnostic workup in the cervical metastasis of carcinoma from an unknown primary tumor (UPT). In the present study, SUV(max) of PET/CT in the cervical lymph node may serve as a prognostic factor of cervical metastasis of carcinoma from a UPT based on the limited number of patients. Further studies are needed to confirm these findings.

Efficacy of fluoro-2-deoxy-D-glucose positron emission tomography to evaluate responses to concurrent chemoradiotherapy for head and neck squamous cell carcinoma

OBJECTIVE

This study evaluates the utility of fluorodeoxyglucose-positron emission tomography (FDG-PET) in patients with head and neck squamous cell carcinoma (HNSCC) who received concurrent chemoradiotherapy (CCRT).

METHODS

Sixty-five patients were recruited for this study between November 2002 and April 2007. The FDG-PET scan was performed before treatment and 4-6 weeks after treatment.

RESULTS

The mean of maximum standardized uptake value (SUVmax) before treatment at the primary tumor site was 8.1 (range, 2-22). The sensitivity of FDG-PET for the diagnosis of primary tumor site was 98%. The mean of SUVmax after treatment was 2.6 (range, 2-5). The sensitivity, specificity, and accuracy of FDG-PET for the diagnosis of primary tumor site after treatment were 100%, 40%, and 46%, respectively. The mean of SUVmax before treatment at the nodal site was 4.7 (range, 2-16). The mean of SUVmax after treatment was 2.0 (range, 2-6.7). The pre-treatment SUVmax of T2, T3, and T4 stages were significantly higher than that of the T1 stage. The N stage had no correlation in terms of the pre-treatment nodal site SUVmax.

CONCLUSION

Our results indicate that FDG-PET is a useful imaging method for evaluating the response of CCRT in patients with HNSCC. However, performing FDG-PET 4-6 weeks after treatment may be too early as it may give false-positive results due to fibrosis and scarring.