Multifunctional profiling of non-small cell lung cancer using 18F-FDG PET/CT and volume perfusion CT

Surgical prognosis of lung invasive mucinous and non-mucinous adenocarcinoma: propensity score matched analysis

OBJECTIVES

Invasive mucinous adenocarcinoma exhibits distinct prognostic outcomes compared to non-mucinous adenocarcinoma (ADC). This study investigated and compared the clinical outcomes and prognostic factors of invasive mucinous and non-mucinous ADC patients.

METHODS

This retrospective study included patients who underwent curative surgery for ADC between 2011 and 2021. Patient characteristics were balanced using propensity score matching. Cumulative incidence was analysed to evaluate cancer recurrence incidence, and the Kaplan-Meier method was used to calculate overall survival (OS) for each group.

RESULTS

A total of 6101 patients were included. After matching, the non-mucinous group and mucinous groups comprised 798 and 408 patients, respectively. The patients in the mucinous group had a lower recurrence incidence than those in the non-mucinous group (P = 0.014). The recurrence incidence in the mucinous group was between those of grades 1 (P = 0.011) and 2 (P = 0.012) and the OS rates were comparable to those of grades 2 (P = 0.6) and 3 (P = 0.2). Multivariable analysis revealed that the maximal standardized uptake value [hazard ratio (HR): 1.13, P = 0.11] and progressed pathological stages (pStage II, HR: 3.9, P = 0.028; pStage III, HR: 8.33, P = 0.038) served as adverse prognostic factors for the mucinous group.

CONCLUSIONS

Patients with mucinous ADC demonstrated lower recurrence incidence and similar OS rates compared to those with non-mucinous ADC. The recurrence incidence of mucinous ADC was between those of International Association for the Study of Lung Cancer grades 1 and 2, with the OS rates comparable to those of grades 2 and 3.

CLINICAL REGISTRATION NUMBER

None.

Relationship between 18F-FDG PET/CT Semi-Quantitative Parameters and International Association for the Study of Lung Cancer, American Thoracic Society/European Respiratory Society Classification in Lung Adenocarcinomas

Objective

To investigate the relationship between ¹⁸F-FDG PET/CT semi-quantitative parameters and the International Association for the Study of Lung Cancer, American Thoracic Society/European Respiratory Society (IASLC/ATS/ERS) histopathologic classification, including histological subtypes, proliferation activity, and somatic mutations.

Materials and Methods

This retrospective study included 419 patients (150 males, 269 females; median age, 59.0 years; age range, 23.0–84.0 years) who had undergone surgical removal of stage IA–IIIA lung adenocarcinoma and had preoperative PET/CT data of lung tumors. The maximum standardized uptake values (SUVmax), background-subtracted volume (BSV), and background-subtracted lesion activity (BSL) derived from PET/CT were measured. The IASLC/ATS/ERS subtypes, Ki67 score, and epidermal growth factor/anaplastic lymphoma kinase (EGFR/ALK) mutation status were evaluated. The PET/CT semi-quantitative parameters were compared between the tumor subtypes using the Mann–Whitney U test or the Kruskal–Wallis test. The optimum cutoff values of the PET/CT semi-quantitative parameters for distinguishing the IASLC/ATS/ERS subtypes were calculated using receiver operating characteristic curve analysis. The correlation between the PET/CT semi-quantitative parameters and pathological parameters was analyzed using Spearman’s correlation. Statistical significance was set at p < 0.05.

Results

SUVmax, BSV, and BSL values were significantly higher in invasive adenocarcinoma (IA) than in minimally IA (MIA), and the values were higher in MIA than in adenocarcinoma in situ (AIS) (all p < 0.05). Remarkably, an SUVmax of 0.90 and a BSL of 3.62 were shown to be the optimal cutoff values for differentiating MIA from AIS, manifesting as pure ground-glass nodules with 100% sensitivity and specificity. Metabolic-volumetric parameters (BSV and BSL) were better potential independent factors than metabolic parameters (SUVmax) in differentiating growth patterns. SUVmax and BSL, rather than BSV, were strongly or moderately correlated with Ki67 in most subtypes, except for the micropapillary and solid predominant groups. PET/CT parameters were not correlated with EGFR/ALK mutation status.

Conclusion

As noninvasive surrogates, preoperative PET/CT semi-quantitative parameters could imply IASLC/ATS/ERS subtypes and Ki67 index and thus may contribute to improved management of precise surgery and postoperative adjuvant therapy.

Potential application value of PET/computed tomography in retroperitoneal leiomyosarcoma and a literature review

OBJECTIVE

To analyze the fluorine-18 fludeoxyglucose PET/computed tomography (18F-FDG PET/CT) findings of retroperitoneal leiomyosarcoma (RLMS) and the role of this method in differentiating between benign and malignant masses and classifying the malignant degree to improve the understanding of this rare disease.

METHODS

Eight leiomyomas (A group), 13 RLMSs (B group), and 20 postoperative recurrence/metastasis RLMSs (C group) were enrolled. PET/CT features of B group were analyzed. The differences of metabolic parameters between three groups were compared, receiver operating characteristic (ROC) curve analysis was performed to group A and B, and correlation analysis was performed to subgroup B.

RESULTS

(1) The RLMS patients were more likely to be female, and PET/CT showed a high degree of heterogeneous metabolism in the soft tissue mass. (2) The standardized uptake value (SUV) of RLMS were significantly higher than those of benign leiomyomas (P < 0.05). The area under the ROC curve was 0.909, the sensitivity and specificity for diagnosing RLMS were 0.923 and 0.750, respectively, The SUVmax and SUVstd of primary RLMS were moderately associated with the Ki67 index. The mean SUVmax in the G1, G2 and G3 subgroups increased successively (4.15 ± 0.35, 6.47 ± 0.83, and 10.13 ± 4.29, respectively). (3) Primary RLMS was characterized by local invasion, but hematogenous metastasis and lymph node metastasis were rare. Postoperative recurrence/metastasis of RLMS was characterized by local recurrence and hematogenous metastasis, but lymph node metastasis was rare.

CONCLUSION

PET/CT has potential value in the preoperative staging, benign and malignant differentiation, malignant degree classification and postoperative follow-up of RLMS.

Associations Between FDG PET and Expression of VEGF and Microvessel Density in Different Solid Tumors: A Meta-analysis

BACKGROUND

To date, there are inconsistent data about relationships between 2-deoxy-2 [¹⁸F] fluoro-D-glucose positron emission tomography (FDG-PET) and expression of vascular endothelial growth factor (VEGF) and microvessel density (MVD). The aim of the present meta-analysis was to systematize the reported data about associations between maximal standardized uptake value (SUV_max) derived from FDG PET and expression of VEGF and as well as MVD.

METHODS

MEDLINE library, SCOPUS and EMBASE data bases were screened for relationships between SUV_max and VEGF/MVD up to October 2019. Overall, in 18 studies correlations between SUV_max and VEGF and in 13 studies correlations between SUV_max and MVD were reported. The following data were extracted from the literature: authors, year of publication, number of patients, and correlation coefficients.

RESULTS

Associations between 18F-FDG PET and VEGF were reported in 18 studies (935 patients). The calculated correlation coefficients between SUVmax and VEGF expression ranged from -0.16 to 0.88. The pooled correlation coefficient was 0.32, (95% confidence interval [CI] = [0.15; 0.48]). Associations between 18F-FDG PET and MVD were investigated in 13 studies (593 patients). The reported correlation coefficients ranged from -0.23 to 0.91. The pooled correlation coefficient was 0.27, (95% CI = [0.00; 0.53]). Analysis of MVD based on CD105 immunohistochemical staining was performed in four studies (117 patients). The pooled correlation coefficient was 0.41 (95% CI = [0.22; 0.59]). In three reports with 233 patients, MVD was estimated by staining with CD31 antibody. The pooled correlation coefficient was 0.01, (95% CI = [-0.44; 0.47]). Finally, in 9 studies (280 patients) MVD was performed on CD34 stained specimens. The pooled correlation coefficient was 0.36, (95% CI = [0.09; 0.63]).

CONCLUSION

SUV_max of FDG PET correlated weakly with expression of VEGF and with MVD. Therefore, FDG PET cannot predict neoangiogenesis in malignant tumors.

Predicting pathological complete response (pCR) after stereotactic ablative radiation therapy (SABR) of lung cancer using quantitative dynamic [18F]FDG PET and CT perfusion: a prospective exploratory clinical study

BACKGROUND

Stereotactic ablative radiation therapy (SABR) is effective in treating inoperable stage I non-small cell lung cancer (NSCLC), but imaging assessment of response after SABR is difficult. This prospective study aimed to develop a predictive model for true pathologic complete response (pCR) to SABR using imaging-based biomarkers from dynamic [¹⁸F]FDG-PET and CT Perfusion (CTP).

METHODS

Twenty-six patients with early-stage NSCLC treated with SABR followed by surgical resection were included, as a pre-specified secondary analysis of a larger study. Dynamic [¹⁸F]FDG-PET and CTP were performed pre-SABR and 8-week post. Dynamic [¹⁸F]FDG-PET provided maximum and mean standardized uptake value (SUV) and kinetic parameters estimated using a previously developed flow-modified two-tissue compartment model while CTP measured blood flow, blood volume and vessel permeability surface product. Recursive partitioning analysis (RPA) was used to establish a predictive model with the measured PET and CTP imaging biomarkers for predicting pCR. The model was compared to current RECIST (Response Evaluation Criteria in Solid Tumours version 1.1) and PERCIST (PET Response Criteria in Solid Tumours version 1.0) criteria.

RESULTS

RPA identified three response groups based on tumour blood volume before SABR (BV_pre-SABR) and change in SUV_max (ΔSUV_max), the thresholds being BV_pre-SABR = 9.3 mL/100 g and ΔSUV_max = - 48.9%. The highest true pCR rate of 92% was observed in the group with BV_pre-SABR < 9.3 mL/100 g and ΔSUV_max < - 48.9% after SABR while the worst was observed in the group with BV_pre-SABR ≥ 9.3 mL/100 g (0%). RPA model achieved excellent pCR prediction (Concordance: 0.92; P = 0.03). RECIST and PERCIST showed poor pCR prediction (Concordance: 0.54 and 0.58, respectively).

CONCLUSIONS

In this study, we developed a predictive model based on dynamic [¹⁸F]FDG-PET and CT Perfusion imaging that was significantly better than RECIST and PERCIST criteria to predict pCR of NSCLC to SABR. The model used BV_pre-SABR and ΔSUV_max which correlates to tumour microvessel density and cell proliferation, respectively and warrants validation with larger sample size studies.

TRIAL REGISTRATION

MISSILE-NSCLC, NCT02136355 (ClinicalTrials.gov). Registered May 8, 2014, https://clinicaltrials.gov/ct2/show/NCT02136355.

Imaging Pulmonary Blood Flow Using Pseudocontinuous Arterial Spin Labeling (PCASL) With Balanced Steady-State Free-Precession (bSSFP) Readout at 1.5T

BACKGROUND

Quantitative assessment of pulmonary blood flow and visualization of its temporal and spatial distribution without contrast media is of clinical significance.

PURPOSE

To assess the potential of electrocardiogram (ECG)-triggered pseudocontinuous arterial spin labeling (PCASL) imaging with balanced steady-state free-precession (bSSFP) readout to measure lung perfusion under free-breathing (FB) conditions and to study temporal and spatial characteristics of pulmonary blood flow.

STUDY TYPE

Prospective, observational.

SUBJECTS

Fourteen volunteers; three patients with pulmonary embolism.

FIELD STRENGTH/SEQUENCES

1.5T, PCASL-bSSFP.

ASSESSMENT

The pulmonary trunk was labeled during systole. The following examinations were performed: 1) FB and timed breath-hold (TBH) examinations with a postlabeling delay (PLD) of 1000 msec, and 2) TBH examinations with multiple PLDs (100-1500 msec). Scan-rescan measurements were performed in four volunteers and one patient. Images were registered and the perfusion was evaluated in large vessels, small vessels, and parenchyma. Mean structural similarity indices (MSSIM) was computed and time-to-peak (TTP) of parenchymal perfusion in multiple PLDs was evaluated. Image quality reading was performed with three independent blinded readers.

STATISTICAL TESTS

Wilcoxon test to compare MSSIM, perfusion, and Likert scores. Spearman's correlation to correlate TTP and cardiac cycle duration. The repeatability coefficient (RC) and within-subject coefficient of variation (wCV) for scan-rescan measurements. Intraclass correlation coefficient (ICC) for interreader agreement.

RESULTS

Image registration resulted in a significant (P < 0.05) increase of MSSIM. FB perfusion values were 6% higher than TBH (3.28 ± 1.09 vs. 3.10 ± 0.99 mL/min/mL). TTP was highly correlated with individuals' cardiac cycle duration (Spearman = 0.89, P < 0.001). RC and wCV were better for TBH than FB (0.13-0.19 vs. 0.47-1.54 mL/min/mL; 6-7 vs. 19-60%). Image quality was rated very good, with ICCs 0.71-0.89.

DATA CONCLUSION

ECG-triggered PCASL-bSSFP imaging of the lung at 1.5T can provide very good image quality and quantitative perfusion maps even under FB. The course of labeled blood through the lung shows a strong dependence on the individuals' cardiac cycle duration.

LEVEL OF EVIDENCE

2 TECHNICAL EFFICACY STAGE: 2 J. MAGN. RESON. IMAGING 2020;52:1767-1782.

The flow-metabolism ratio might predict treatment response and survival in patients with locally advanced esophageal squamous cell carcinoma

Background

Perfusion CT can offer functional information about tumor angiogenesis, and ¹⁸F-FDG PET/CT quantifies the glucose metabolic activity of tumors. This prospective study aims to investigate the value of biologically relevant imaging biomarkers for predicting treatment response and survival outcomes in patients with locally advanced esophageal squamous cell cancer (LA ESCC).

Methods

Twenty-seven patients with pathologically proven ESCC were included. All patients had undergone perfusion CT and ¹⁸F-FDG PET/CT using separate imaging systems before receiving definitive chemoradiotherapy (dCRT). The perfusion parameters included blood flow (BF), blood volume (BV), and time to peak (TTP), and the metabolic parameters included maximum standardized uptake value (SUVmax), metabolic tumor volume (MTV), and total lesion glycolysis (TLG). The flow-metabolism ratio (FMR) was defined as BF divided by SUVmax. Statistical methods used included Spearman’s rank correlation, Mann–Whitney U test or two-sample t test, receiver operating characteristic (ROC) curve analysis, the Kaplan–Meier method, and Cox proportional hazards models.

Results

The median overall survival (OS) and progression-free survival (PFS) were 18 and 11.6 months, respectively. FMR was significantly positively correlated with BF (r = 0.886, p < 0.001) and negatively correlated with SUVmax (r = − 0.547, p = 0.003) and TTP (r = − 0.462, p = 0.015) in the tumors. However, there was no significant correlation between perfusion and PET parameters. After dCRT, 14 patients (51.9%) were identified as responders, and another 13 were nonresponders. The BF and FMR of the responders were significantly higher than those of the nonresponders (42.05 ± 16.47 vs 27.48 ± 8.55, p = 0.007; 3.18 ± 1.15 vs 1.84 ± 0.65, p = 0.001). The ROC curves indicated that the FMR [area under the curve (AUC) = 0.846] was a better biomarker for predicting treatment response than BF (AUC = 0.802). Univariable Cox analysis revealed that of all imaging parameters, only the FMR was significantly correlated with overall survival (OS) (p = 0.015) and progression-free survival (PFS) (p = 0.017). Specifically, patients with a lower FMR had poorer survival. Multivariable analysis showed that after adjusting for age, clinical staging, and treatment response, the FMR remained an independent predictor of OS (p = 0.026) and PFS (p = 0.014).

Conclusions

The flow-metabolism mismatch demonstrated by a low FMR shows good potential in predicting chemoradiotherapy sensitivity and prognosis in ESCC.

Radioimmunoimaging of 125I-labeled anti-CD93 monoclonal antibodies in a xenograft model of non-small cell lung cancer

Lung cancer, especially non-small cell lung cancer (NSCLC), is the most common malignant tumor associated with poor prognosis. Angiogenesis plays a vital role in NSCLC, and could be used in tumor staging and therapy evaluation. CD93 (C1q receptor) is reportedly a key regulator of tumor angiogenesis. In the present study, the efficacy and specificity of a ¹²⁵I-labeled CD93-specific monoclonal antibody (¹²⁵I-anti-CD93 mAb) in detecting NSCLC xenografts were analyzed, and the association between CD93 expression and ¹²⁵I-anti-CD93 mAb uptake by tumors was evaluated. The targeting ability of ¹²⁵I-anti-CD93 mAb enabled its rapid, continuous and highly specific accumulation in CD93-expressing tumors in vivo. These results revealed the potential applicability of ¹²⁵I-anti-CD93 mAb for non-invasive imaging diagnosis of CD93-positive NSCLC.

Noninvasive assessment and quantification of tumor vascularization using [18F]FDG-PET/CT and CE-CT in a tumor model with modifiable angiogenesis-an animal experimental prospective cohort study

Background

This study investigated the noninvasive assessment of tumor vascularization with clinical F-18-fluorodeoxyglucose positron emission tomography/computed tomography and contrast-enhanced computed tomography ([18F]FDG-PET/CT and CE-CT) in experimental human xenograft tumors with modifiable vascularization and compared results to histology. Tumor xenografts with modifiable vascularization were established in 71 athymic nude rats by subcutaneous transplantation of human non-small-cell lung cancer (NSCLC) cells. Four different groups were transplanted with two different tumor cell lines (either A549 or H1299) alone or tumors co-transplanted with rat glomerular endothelial (RGE) cells, the latter to increase vascularization. Tumors were assessed noninvasively by [18F]FDG PET/CT and contrast-enhanced CT (CE-CT) using clinical scanners. This was followed by histological examinations evaluating tumor vasculature (CD-31 and intravascular fluorescent beads).

Results

In both tumor lines (A549 and H1299), co-transplantation of RGE cells resulted in faster growth rates [maximal tumor diameter of 20 mm after 22 (± 1.2) as compared to 45 (± 1.8) days, p < 0.001], higher microvessel density (MVD) determined histologically after CD-31 staining [171.4 (± 18.9) as compared to 110.8 (± 11) vessels per mm², p = 0.002], and higher perfusion as indicated by the number of beads [1.3 (± 0.1) as compared to 1.1 (± 0.04) beads per field of view, p = 0.001]. In [18F]FDG-PET/CT, co-transplanted tumors revealed significantly higher standardized uptake values [SUVmax, 2.8 (± 0.2) as compared to 1.1 (± 0.1), p < 0.001] and larger metabolic active volumes [2.4 (± 0.2) as compared to 0.4 (± 0.2) cm³, p < 0.001] than non-co-transplanted tumors. There were significant correlations for vascularization parameters derived from histology and [18F]FDG PET/CT [beads and SUVmax, r = 0.353, p = 0.005; CD-31 and SUVmax, r = 0.294, p = 0.036] as well as between CE-CT and [18F]FDG PET/CT [contrast enhancement and SUVmax, r = 0.63, p < 0.001; vital CT tumor volume and metabolic PET tumor volume, r = 0.919, p < 0.001].

Conclusions

In this study, a human xenograft tumor model with modifiable vascularization implementable for imaging, pharmacological, and radiation therapy studies was successfully established. Both [18F]FDG-PET/CT and CE-CT are capable to detect parameters closely connected to the degree of tumor vascularization, thus they can help to evaluate vascularization in tumors noninvasively. [18F]FDG-PET may be considered for characterization of tumors beyond pure glucose metabolism and have much greater contribution to diagnostics in oncology.

Assessment of tumour response after stereotactic ablative radiation therapy for lung cancer: A prospective quantitative hybrid 18 F-fluorodeoxyglucose-positron emission tomography and CT perfusion study

INTRODUCTION

Stereotactic ablative radiotherapy (SABR) is a guideline-recommended treatment for inoperable stage I non-small cell lung cancer (NSCLC), but imaging assessment of response after SABR is difficult. The goal of this study was to evaluate imaging-based biomarkers of tumour response using dynamic ¹⁸ F-FDG-PET and CT perfusion (CTP).

METHODS

Thirty-one patients with early-stage NSCLC participated in this prospective correlative study. Each underwent dynamic ¹⁸ F-FDG-PET/CTP studies on a PET/CT scanner pre- and 8 weeks post-SABR. The dynamic ¹⁸ F-FDG-PET measured the tumour SUV_max , SUV_mean and the following parameters: K₁ , k₂ , k₃ , k₄ and K_i , all using the Johnson-Wilson-Lee kinetic model. CTP quantitatively mapped BF, BV, MTT and PS in tumours and measured largest tumour diameter. Since free-breathing was allowed during CTP scanning, non-rigid image registration of CT images was applied to minimize misregistration before generating the CTP functional maps. Differences between pre- and post-SABR imaging-based parameters were compared.

RESULTS

Tumour size changed only slightly after SABR (median 26 mm pre-SABR vs. 23 mm post-SABR; P = 0.01). However, dynamic ¹⁸ F-FDG-PET and CTP study showed substantial and significant changes in SUV_max , SUV_mean , k₃ , k₄ and K_i . Significant decreases were evident in SUV_max (median 6.1 vs. 2.6; P < 0.001), SUV_mean (median 2.5 vs. 1.5; P < 0.001), k₃ (relative decrease of 52%; P = 0.002), K_i (relative decrease of 27%; P = 0.03), whereas there was an increase in k₄ (+367%; P < 0.001).

CONCLUSIONS

Hybrid ¹⁸ F-FDG-PET/CTP allowed the response of NSCLC to SABR to be assessed regarding metabolic and functional parameters. Future studies are needed, with correlation with long-term outcomes, to evaluate these findings as potential imaging biomarkers of response.

CT Perfusion in Patients with Lung Cancer: Squamous Cell Carcinoma and Adenocarcinoma Show a Different Blood Flow

Objectives

To characterize tumour baseline blood flow (BF) in two lung cancer subtypes, adenocarcinoma (AC) and squamous cell carcinoma (SCC), also investigating those “borderline” cases whose perfusion value is closer to the group mean of the other histotype.

Materials and Methods

26 patients (age range 36-81 years) with primary Non-Small Cell Lung Cancer (NSCLC), subdivided into 19 AC and 7 SCC, were enrolled in this study and underwent a CT perfusion, at diagnosis. BF values were computed according to the maximum-slope method and unreliable values (e.g., arising from artefacts or vessels) were automatically removed. The one-tail Welch's t-test (p-value <0.05) was employed for statistical assessment.

Results

At diagnosis, mean BF values (in [mL/min/100g]) of AC group [(83.5 ± 29.4)] are significantly greater than those of SCC subtype [(57.0 ± 27.2)] (p-value = 0.02). However, two central SCCs undergoing artefacts from vena cava and pulmonary artery have an artificially increased mean BF.

Conclusions

The different hemodynamic behaviour of AC and SCC should be considered as a biomarker supporting treatment planning to select the patients, mainly with AC, that would most benefit from antiangiogenic therapies. The significance of results was achieved by automatically detecting and excluding artefactual BF values.

Standardized Uptake Values Derived from 18F-FDG PET May Predict Lung Cancer Microvessel Density and Expression of KI 67, VEGF, and HIF-1α but Not Expression of Cyclin D1, PCNA, EGFR, PD L1, and p53

Background

Our purpose was to provide data regarding relationships between ¹⁸F-FDG PET and histopathological parameters in lung cancer.

Methods

MEDLINE library was screened for associations between PET parameters and histopathological features in lung cancer up to December 2017. Only papers containing correlation coefficients between PET parameters and histopathological findings were acquired for the analysis. Overall, 40 publications were identified.

Results

Associations between SUV and KI 67 were reported in 23 studies (1362 patients). The pooled correlation coefficient was 0.44. In 2 studies (180 patients), relationships between SUV and expression of cyclin D1 were analyzed (pooled correlation coefficient = 0.05). Correlation between SUV and HIF-1α was investigated in 3 studies (288 patients), and the pooled correlation coefficient was 0.42. In 5 studies (310 patients), associations between SUV and MVD were investigated (pooled correlation coefficient = 0.54). In 6 studies (305 patients), relationships between SUV and p53 were analyzed (pooled correlation coefficient = 0.30). In 6 studies (415 patients), associations between SUV and VEGF expression were investigated (pooled correlation coefficient = 0.44). In 5 studies (202 patients), associations between SUV and PCNA were investigated (pooled correlation coefficient = 0.32). In 3 studies (718 patients), associations between SUV and expression of PD L1 were analyzed (pooled correlation coefficient = 0.36). Finally, in 5 studies (409 patients), associations between SUV and EGFR were investigated (pooled correlation coefficient = 0.38).

Conclusion

SUV may predict microvessel density and expression of VEGF, KI 67, and HIF-1α in lung cancer.

Quantitative assessment of Zirconium-89 labeled cetuximab using PET/CT imaging in patients with advanced head and neck cancer: a theragnostic approach

Biomarkers predicting treatment response to the monoclonal antibody cetuximab in locally advanced head and neck squamous cell carcinomas (LAHNSCC) are lacking. We hypothesize that tumor accessibility is an important factor in treatment success of the EGFR targeting drug. We quantified uptake of cetuximab labeled with Zirconium-89 (⁸⁹Zr) using PET/CT imaging.

Seventeen patients with stage III-IV LAHNSCC received a loading dose unlabeled cetuximab, followed by 10 mg 54.5±9.6 MBq ⁸⁹Zr-cetuximab. PET/CT images were acquired either 3 and 6 or 4 and 7 days post-injection. ⁸⁹Zr-cetuximab uptake was quantified using standardized uptake value (SUV) and tumor-to-background ratio (TBR), and correlated to EGFR immunohistochemistry. TBR was compared between scan days to determine optimal timing.

Uptake of ⁸⁹Zr-cetuximab varied between patients (day 6-7: SUV_peak range 2.5-6.2). TBR increased significantly (49±28%, p < 0.01) between first (1.1±0.3) and second scan (1.7±0.6). Between groups with a low and high EGFR expression a significant difference in SUV_mean (2.1 versus 3.0) and SUV_peak (3.2 versus 4.7) was found, however, not in TBR. Data is available at www.cancerdata.org (DOI: 10.17195/candat.2016.11.1).

In conclusion, ⁸⁹Zr-cetuximab PET imaging shows large inter-patient variety in LAHNSCC and provides additional information over FDG-PET and EGFR expression. Validation of the predictive value is recommended with scans acquired 6-7 days post-injection.

Can visual assessment of blood flow patterns by dynamic contrast-enhanced computed tomography distinguish between malignant and benign lung tumors?

Background

Dynamic contrast-enhanced computed tomography (DCE-CT) is a tool, which, in theory, can quantify the blood flow and blood volume of tissues. In structured qualitative analysis, parametric color maps yield a visual impression of the blood flow and blood volume within the tissue being studied, allowing for quick identification of the areas with the highest or lowest blood flow and blood volume.

Purpose

To examine whether DCE-CT could be used to distinguish between malignant and benign lung tumors in patients with suspected lung cancer.

Material and Methods

Fifty-nine patients with suspected lung cancer and a lung tumor on their chest radiograph were included for DCE-CT. The tumors were categorized using structured qualitative analysis of tumor blood flow patterns. Histopathology was used as reference standard.

Results

Using structured qualitative analysis of tumor blood flow patterns, it was possible to distinguish between malignant and benign lung tumors (Fisher–Freeman–Halton exact test, P = 0.022). The inter-reader agreement of this method of analysis was slight to moderate (kappa = 0.30; 95% confidence interval [CI] = 0.13–0.46).

Conclusion

DCE-CT in suspected lung cancer using structured qualitative analysis of tumor blood flow patterns is accurate as well as somewhat reproducible. However, there are significant limitations to DCE-CT.

Adaptive statistical iterative reconstruction improves image quality without affecting perfusion CT quantitation in primary colorectal cancer

OBJECTIVES

To determine the effect of Adaptive Statistical Iterative Reconstruction (ASIR) on perfusion CT (pCT) parameter quantitation and image quality in primary colorectal cancer.

METHODS

Prospective observational study. Following institutional review board approval and informed consent, 32 patients with colorectal adenocarcinoma underwent pCT (100 kV, 150 mA, 120 s acquisition, axial mode). Tumour regional blood flow (BF), blood volume (BV), mean transit time (MTT) and permeability surface area product (PS) were determined using identical regions-of-interests for ASIR percentages of 0%, 20%, 40%, 60%, 80% and 100%. Image noise, contrast-to-noise ratio (CNR) and pCT parameters were assessed across ASIR percentages. Coefficients of variation (CV), repeated measures analysis of variance (rANOVA) and Spearman' rank order correlation were performed with statistical significance at 5%.

RESULTS

With increasing ASIR percentages, image noise decreased by 33% while CNR increased by 61%; peak tumour CNR was greater than 1.5 with 60% ASIR and above. Mean BF, BV, MTT and PS differed by less than 1.8%, 2.9%, 2.5% and 2.6% across ASIR percentages. CV were 4.9%, 4.2%, 3.3% and 7.9%; rANOVA P values: 0.85, 0.62, 0.02 and 0.81 respectively.

CONCLUSIONS

ASIR improves image noise and CNR without altering pCT parameters substantially.

Volumes Learned: It Takes More Than Size to "Size Up" Pulmonary Lesions

RATIONALE AND OBJECTIVES

This study aimed to review the current understanding and capabilities regarding use of imaging for noninvasive lesion characterization and its relationship to lung cancer screening and treatment.

MATERIALS AND METHODS

Our review of the state of the art was broken down into questions about the different lung cancer image phenotypes being characterized, the role of imaging and requirements for increasing its value with respect to increasing diagnostic confidence and quantitative assessment, and a review of the current capabilities with respect to those needs.

RESULTS

The preponderance of the literature has so far been focused on the measurement of lesion size, with increasing contributions being made to determine the formal performance of scanners, measurement tools, and human operators in terms of bias and variability. Concurrently, an increasing number of investigators are reporting utility and predictive value of measures other than size, and sensitivity and specificity is being reported. Relatively little has been documented on quantitative measurement of non-size features with corresponding estimation of measurement performance and reproducibility.

CONCLUSIONS

The weight of the evidence suggests characterization of pulmonary lesions built on quantitative measures adds value to the screening for, and treatment of, lung cancer. Advanced image analysis techniques may identify patterns or biomarkers not readily assessed by eye and may also facilitate management of multidimensional imaging data in such a way as to efficiently integrate it into the clinical workflow.

The asphericity of the metabolic tumour volume in NSCLC: correlation with histopathology and molecular markers

PURPOSE

Asphericity (ASP) is a tumour shape descriptor based on the PET image. It quantitates the deviation from spherical of the shape of the metabolic tumour volume (MTV). In order to identify its biological correlates, we investigated the relationship between ASP and clinically relevant histopathological and molecular signatures in non-small-cell lung cancer (NSCLC).

METHODS

The study included 83 consecutive patients (18 women, aged 66.4 ± 8.9 years) with newly diagnosed NSCLC in whom PET/CT with ¹⁸F-FDG had been performed prior to therapy. Primary tumour resection specimens and core biopsies were used for basic histopathology and determination of the Ki-67 proliferation index. EGFR status, VEGF, p53 and ALK expression were obtained in a subgroup of 44 patients. The FDG PET images of the primary tumours were delineated using an automatic algorithm based on adaptive thresholding taking into account local background. In addition to ASP, SUVmax, MTV and some further descriptors of shape and intratumour heterogeneity were assessed as semiquantitative PET measures.

RESULTS

SUVmax, MTV and ASP were associated with pathological T stage (Kruskal-Wallis, p = 0.001, p < 0.0005 and p < 0.0005, respectively) and N stage (p = 0.017, p = 0.003 and p = 0.002, respectively). Only ASP was associated with M stage (p = 0.026). SUVmax, MTV and ASP were correlated with Ki-67 index (Spearman's rho = 0.326/p = 0.003, rho = 0.302/p = 0.006 and rho = 0.271/p = 0.015, respectively). The latter correlations were considerably stronger in adenocarcinomas than in squamous cell carcinomas. ASP, but not SUVmax or MTV, showed a tendency for a significant association with the extent of VEGF expression (p = 0.058). In multivariate Cox regression analysis, ASP (p < 0.0005) and the presence of distant metastases (p = 0.023) were significantly associated with progression-free survival. ASP (p = 0.006), the presence of distant metastases (p = 0.010), and Ki-67 index (p = 0.062) were significantly associated with overall survival.

CONCLUSION

The ASP of primary NSCLCs on FDG PET images is associated with tumour dimensions and molecular markers of proliferation and angiogenesis.

Stereotactic Comparison Study of (18)F-Alfatide and (18)F-FDG PET Imaging in an LLC Tumor-Bearing C57BL/6 Mouse Model

This study aimed to stereotactically compare the PET imaging performance of (18)F-Alfatide ((18)F-ALF-NOTA-PRGD2, denoted as (18)F-Alfatide) and (18)F-fluorodeoxyglucose (FDG) and immunohistochemistry (IHC) staining in Lewis lung carcinoma (LLC) tumor-bearing C57BL/6 mouse model. (18)F-FDG standard uptake values (SUVs) were higher than (18)F-Alfatide SUVs in tumors, most of the normal tissues and organs except for the bladder. Tumor-to-brain, tumor-to-lung, and tumor-to-heart ratios of (18)F-Alfatide PET were significantly higher than those of (18)F-FDG PET (P < 0.001). The spatial heterogeneity of the tumors was detected, and the tracer accumulation enhanced from the outer layer to the inner layer consistently using the two tracers. The parameters of the tumors were significantly correlated with each other between (18)F-FDG SUV and GLUT-1 (R = 0.895, P < 0.001), (18)F-Alfatide SUV and αvβ3 (R = 0.595, P = 0.019), (18)F-FDG SUV and (18)F-Alfatide SUV (R = 0.917, P < 0.001), and GLUT-1 and αvβ3 (R = 0.637, P = 0.011). Therefore, (18)F-Alfatide PET may be an effective tracer for tumor detection, spatial heterogeneity imaging and an alternative supplement to (18)F-FDG PET, particularly for patients with enhanced characteristics in the brain, chest tumors or diabetes, meriting further study.

Feasibility of assessing pulmonary blood volume using C-arm CT during transpulmonary chemoperfusion and chemoembolization in primary and secondary lung tumours

OBJECTIVE

Assessment of parenchymal blood volume (PBV) of primary and secondary pulmonary malignancies by using a C-arm CT, regarding its role in detecting early functional response to transpulmonary chemoembolization (TPCE) and clinical practicability.

METHODS

21 patients with a mean age of 56.77 years, who were assigned to TPCE during their palliative treatment, were included. PBV and the diameter of tumours were analyzed. PBV maps were calculated from three-dimensional CT-angiographic (3D-CTA) data sets. Imaging was performed on a flat detector, C-arm CT. Groups of response were classified according to the criteria of the response evaluation criteria in solid tumours. Statistically significant differences were determined and Pearson's regression analysis correlated PBV and diameter as parameters of response to treatment.

RESULTS

During 4.91 sessions, median diameter increased 18.18% (p > 0.05) and PBV reduced 39.62% (p > 0.05). Functional and imaging response per tumour was statistical significantly different (p ≤ 0.05). Correlation coefficient was r = 0.058. 2/41 tumours showed partial response; 31/41 tumours showed stable disease; and 8/41 tumours showed progressive disease. The highest pre-treatment PBV values were measured in decreasing tumours (206.93 ml l(-1)), and the lowest values were measured in increasing tumours (60.17 ml l(-1); p > 0.05). The lowest values were also measured in lung cancer (53.02 ml l(-1)) that was significantly different to uterine leiomyosarcoma (103.31 ml l(-1)) and renal cell cancer (113.14 ml l(-1); p ≤ 0.05).

CONCLUSION

Assessment of PBV maps by using 3D-CTA image data is feasible in the clinical routine. PBV shows a stronger response to TPCE treatment than measurement in diameter and should be considered as a response parameter for early detection.

ADVANCES IN KNOWLEDGE

Assessment of PBV using C-arm CT during TPCE is a feasible technique. Assessment of PBV might be useful in assessing response to treatment.

Prognosis in Resected Invasive Mucinous Adenocarcinomas of the Lung: Related Factors and Comparison with Resected Nonmucinous Adenocarcinomas

INTRODUCTION

In the 2015 World Health Organization classification, invasive mucinous adenocarcinoma (IMA) is categorized as one of various subtypes of lung invasive adenocarcinoma (ADC). However, no comprehensive analysis regarding the clinicoradiologic and prognostic features of IMA has been reported. We aimed to report prognostic factors in IMA and to compare the prognosis of IMAs with that of nonmucinous ADCs.

METHODS

We included 81 patients with a solitary IMA of the lung and analyzed them from the standpoint of clinicoradiologic presentation. Survival rates were assessed and compared with those of 646 resected solitary invasive nonmucinous ADCs.

RESULTS

Patients with IMA showed longer disease-free survival (DFS) than did those with nonmucinous ADCs, whereas overall survival (OS) did not differ significantly (p = 0.023 and p = 0.824, respectively). The DFS of patients with IMA was between that of patients with lepidic predominant (low-grade) and acinar/papillary predominant (intermediate-grade) ADC. In terms of OS, the survival curve of IMA was similar to that of acinar/papillary predominant ADC. Multivariate analysis revealed that tumor size (hazard ratio [HR] = 1.370, 95% confidence interval [CI]: 1.141-1.645, p = 0.001) and maximum standardized uptake value (HR = 1.338, 95% CI: 1.160-1.544, p < 0.001) were independent poor prognostic predictors for DFS. Regarding OS, tumor size (HR = 1.309, 95% CI: 1.092-1.570; p = 0.004) was the only predictor of poor prognosis.

CONCLUSION

Patients with IMA demonstrate a DFS between that of patients with low-grade nonmucinous ADC and that of patients with intermediate-grade nonmucinous ADC and an OS similar to that of patients with intermediate-grade nonmucinous ADC. In IMA, tumor size and maximum standardized uptake value are the factors related to mitigating DFS and tumor size is the only predictor for reduced OS.

Prognostic significance of volume-based 18F-FDG PET/CT parameter in patients with surgically resected non-small cell lung cancer. Comparison with immunohistochemical biomarkers

AIM

We investigated the prognostic value of volume-based 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET) parameters compared with other factors including several immunohistochemical biomarkers in patients with surgically resected non-small cell lung cancer (NSCLC).

PATIENTS, METHODS

STUDY PARTICIPANTS

290 patients with surgically resected and histopathologically confirmed NSCLC. The maxmum standardized uptake value (SUVmax) and metabolic tumour volume (MTV) of the primary tumour were obtained on 18F-FDG PET/ computed tomography (CT) for initial staging and Ki-67 labeling index (LI), p16, CD31 and cyclin E were evaluated in the primary tumours by immunohistochemical staining. Survival analyses for variables including PET parameters, immunohistochemical biomarker and other clinical factors were performed using the Kaplan-Meier method and Cox proportional hazards regression analysis.

RESULTS

In univariate analyses, tumour stage, tumour size, and MTV were significant prognostic factors for decreased overall survival (OS) and disease-free survival (DFS). Multivariate analyses showed MTV and tumour stage were significant predictors of poor OS (MTV, hazard ratio (HR) = 1.135, p = 0.015; stage, HR = 0.644, p = 0.025) and DFS (MTV, HR = 1.128, p = 0.043; stage, HR = 0.541, p = 0.009).

CONCLUSION

The MTV of primary tumours is a significant prognostic factor for survival along with tumour stage in patients with surgically resected NSCLC. The MTV can predict OS and DFS better than immunohistochemical biomarkers.

Assessment of bronchial and pulmonary blood supply in non-small cell lung cancer subtypes using computed tomography perfusion

OBJECTIVES

The aim of this study was to investigate the dual blood supply of non-small cell lung cancer (NSCLC) and its association with tumor subtype, size, and stage, using computed tomography perfusion (CTP).

MATERIALS AND METHODS

A total of 54 patients (median age, 65 years; range, 42-79 years; 15 women, 39 men) with suspected lung cancer underwent a CTP scan of the lung tumor. Pulmonary and bronchial vasculature regions of interest were used to calculate independently CTP parameters (blood flow [BF], blood volume [BV], and mean transit time [MTT]) of the tumor tissue. The mean and maximum pulmonary and bronchial perfusion indexes (PImean and PImax) were calculated. The tumoral volume and the largest tumoral diameter were assessed. Differences in CTP parameters and indexes among NSCLC subtypes, tumor stages and tumor dimensions were analyzed using non-parametric tests.

RESULTS

According to biopsy, 37 patients had NSCLC (22 adenocarcinomas [ACs], 8 squamous cell carcinomas [SCCs], 7 large-cell carcinomas [LCC]). The mean bronchial BF/pulmonary BF, bronchial BV/pulmonary BV, and bronchial MTT/pulmonary MTT was 41.2 ± 30.0/36.9 ± 24.2 mL/100 mL/min, 11.4 ± 9.7/10.4 ± 9.4 mL/100 mL, and 11.4 ± 4.3/14.9 ± 4.4 seconds, respectively. In general, higher bronchial BF than pulmonary BF was observed in NSCLC (P = 0.014). Using a tumoral volume cutoff of 3.5 cm, a significant difference in pulmonary PImax was found (P = 0.028). There was a significantly higher mean pulmonary BF in LCCs and SCCs compared with ACs (P = 0.018 and P = 0.044, respectively), whereas the mean bronchial BF was only significantly higher in LCCs compared with ACs (P = 0.024). Correspondingly, the PImax was significantly higher in LCCs and SCCs than in ACs (P = 0.001 for both). Differences between bronchial and pulmonary PImean and PImax among T stages and Union Internationale Contre le Cancer stages were not statistically significant (P values ranging from 0.691 to 0.753).

CONCLUSIONS

The known dual blood supply of NSCLC, which depends on tumor size and histological subtype, is reflected in CTP parameters, with parameters depending both on tumor size and histological subtype. This has to be accounted for when analyzing NSCLC with CTP.

Multiparametric imaging of patient and tumour heterogeneity in non-small-cell lung cancer: quantification of tumour hypoxia, metabolism and perfusion

Purpose

Multiple imaging techniques are nowadays available for clinical in-vivo visualization of tumour biology. FDG PET/CT identifies increased tumour metabolism, hypoxia PET visualizes tumour oxygenation and dynamic contrast-enhanced (DCE) CT characterizes vasculature and morphology. We explored the relationships among these biological features in patients with non-small-cell lung cancer (NSCLC) at both the patient level and the tumour subvolume level.

Methods

A group of 14 NSCLC patients from two ongoing clinical trials (NCT01024829 and NCT01210378) were scanned using FDG PET/CT, HX4 PET/CT and DCE CT prior to chemoradiotherapy. Standardized uptake values (SUV) in the primary tumour were calculated for the FDG and hypoxia HX4 PET/CT scans. For hypoxia imaging, the hypoxic volume, fraction and tumour-to-blood ratio (TBR) were also defined. Blood flow and blood volume were obtained from DCE CT imaging. A tumour subvolume analysis was used to quantify the spatial overlap between subvolumes.

Results

At the patient level, negative correlations were observed between blood flow and the hypoxia parameters (TBR >1.2): hypoxic volume (−0.65, p = 0.014), hypoxic fraction (−0.60, p = 0.025) and TBR (−0.56, p = 0.042). At the tumour subvolume level, hypoxic and metabolically active subvolumes showed an overlap of 53 ± 36 %. Overlap between hypoxic sub-volumes and those with high blood flow and blood volume was smaller: 15 ± 17 % and 28 ± 28 %, respectively. Half of the patients showed a spatial mismatch (overlap <5 %) between increased blood flow and hypoxia.

Conclusion

The biological imaging features defined in NSCLC tumours showed large interpatient and intratumour variability. There was overlap between hypoxic and metabolically active subvolumes in the majority of tumours, there was spatial mismatch between regions with high blood flow and those with increased hypoxia.

Electronic supplementary material

The online version of this article (doi:10.1007/s00259-015-3169-4) contains supplementary material, which is available to authorized users.

Glucose metabolism in NSCLC is histology-specific and diverges the prognostic potential of 18FDG-PET for adenocarcinoma and squamous cell carcinoma

INTRODUCTION

Biological features of non-small-cell lung carcinomas (NSCLCs) are important determinants for prognosis. In this study, differences in glucose metabolism between adeno- and squamous cell NSCLCs were quantified using the hypoxia and glycolysis-related markers glucose transporter 1 (GLUT1), carbonic anhydrase IX (CAIX), monocarboxylate transporter 1 (MCT1) and 4 (MCT4) vasculature, and 18-fluoro-2-deoxyglucose (FDG)-uptake. Relevance of these markers for disease-free survival (DFS) was analyzed.

METHODS

Patients with curatively resected stage I to II and resectable stage IIIA, cN0-1 adeno- or squamous cell NSCLC, of whom fresh-frozen lung resection biopsies and pretreatment FDG-positron emission tomography (PET) scans were available, were included in this study (n = 108). FDG-uptake was quantified by calculating total lesion glycolysis (TLG). Metabolic marker expression was measured by immunofluorescent staining (protein) and quantitative polymerase chain reaction (messenger ribonucleic acid [mRNA]). Patients were retrospectively evaluated for DFS.

RESULTS

mRNA and protein expression of metabolic markers, with the exception of MCT4, and TLG were higher in squamous cell carcinomas than in adenocarcinomas, whereas adenocarcinomas were better vascularized. Adenocarcinomas had a worse DFS compared with squamous cell carcinomas (p = 0.016) based on the potential to metastasize. High TLG was associated with a worse DFS only in adenocarcinomas.

CONCLUSION

Our findings suggest that the adenocarcinomas exhibit glycolysis under normoxic conditions, whereas squamous cell carcinomas are exposed to diffusion-limited hypoxia resulting in a very high anaerobic glycolytic rate. Although squamous cell carcinomas have a higher FDG-uptake, in general regarded as a poor prognostic factor, adenocarcinomas have a higher metastatic potential and a worse DFS. These findings show that FDG-PET should be interpreted in relation to histology. This may improve the prognostic potential of FDG-PET and may aid in exploiting FDG-PET in treatment strategies allied to histology.

Correlation between the Uptake of 18F-Fluorodeoxyglucose (18F-FDG) and the Expression of Proliferation-Associated Antigen Ki-67 in Cancer Patients: A Meta-Analysis

Objective

To study the correlation between ¹⁸F-FDG uptake and cell proliferation in cancer patients by meta-analysis of published articles.

Methods

We searched PubMed (MEDLINE included), EMBASE, and Cochrane Database of Systematic Review, and selected research articles on the relationship between ¹⁸F-FDG uptake and Ki-67 expression (published between August 1, 1994-August 1, 2014), according to the literature inclusion and exclusion criteria. The publishing language was limited to English. The quality of included articles was evaluated according to the Quality Assessment of Diagnosis Accuracy Studies-2 (QUADAS-2). The correlation coefficient (r) was extracted from the included articles and processed by Fisher's r-to-z transformation. The combined correlation coefficient (r) and the 95% confidence interval (CI) were calculated with STATA 11.0 software under a random-effects model. Begg's test was used to analyze the existence of publication bias and draw funnel plot, and the sources of heterogeneity were explored by sensitivity and subgroup analyses.

Results

According to the inclusion and exclusion criteria, 79 articles were finally included, including 81 studies involving a total of 3242 patients. All the studies had a combined r of 0.44 (95% CI, 0.41-0.46), but with a significant heterogeneity (I² = 80.9%, P<0.01). Subgroup analysis for different tumor types indicated that most subgroups showed a reduced heterogeneity. Malignant melanoma (n = 1) had the minimum correlation coefficient (-0.22) between ¹⁸F-FDG uptake and Ki-67 expression, while the thymic epithelial tumors (TETs; n = 2) showed the maximum correlation coefficient of 0.81. The analytical results confirmed that correlation between ¹⁸F-FDG uptake and Ki-67 expression was extremely significant in TETs, significant in gastrointestinal stromal tumors (GISTs), moderate in patients with lung, breast, bone and soft tissue, pancreatic, oral, thoracic, and uterine and ovarian cancers, average in brain, esophageal and colorectal cancers, and poor in head and neck, thyroid, gastric and malignant melanoma tumors. Subgroup analysis indicated that positron emission tomography (PET) or PET/CT imaging technology or Ki-67 and standardized uptake value (SUV) measurement technology did not significantly affect the results of r values, and Begg's test showed no significant publication bias.

Conclusion

In cancer patients, ¹⁸F-FDG uptake showed a moderate positive correlation with tumor cell proliferation. Different tumor types exhibited varied degree of correlation, and the correlation was significant in TETs and GSTs. However, our results need further validation by clinical trials with a large sample of different tumor types.

(18)F-FDG uptake on PET correlates with biological potential in early oral squamous cell carcinoma

CONCLUSION

The maximum standardized uptake value (SUVmax) of early oral squamous cell carcinoma (OSCC) may have a role as an imaging biomarker for assessment of malignant potential, including cell metabolism and angiogenesis.

OBJECTIVE

The usefulness of (18)F-fluorodeoxyglucose positron emission tomography (FDG-PET) has been proven in various cancers, including OSCC. Moreover, in several carcinomas, the SUVmax of the tumor has been shown to correlate with the histological type, tumor stage, differentiation, and prognosis. Here, we investigated whether the SUVmax of early OSCC was associated with the biological features.

METHODS

Twenty-seven patients with newly diagnosed early OSCC who underwent preoperative FDG-PET and curative surgical resection were included in this study. Tumor sections were stained by immunohistochemistry for glucose transporter 1 (GLUT1), L-type amino acid transporter 1 (LAT1), CD98, microvessels (CD34), cell proliferation marker (Ki-67), and cell cycle regulator (p53). The correlation between SUVmax and clinicopathological findings or the expression level of these molecules was analyzed.

RESULTS

SUVmax of primary OSCC was significantly higher in patients with T2 stage. Moreover, patients whose tumors showed vascular invasion had a tendency to show higher SUVmax. A significant correlation was observed between SUVmax and the expression of LAT1 or microvessel density.

Picture the future: emerging imaging modalities

The past century has witnessed accelerated development in imaging modalities. Better anatomical visualisation and improved data analysis have improved survival rates. Through emerging functional, molecular and structural imaging modalities, better anatomical visualisation has been extended to cellular and molecular detail, improving diagnosis and management of diseases. This article reviews the advances made in emerging imaging modalities as well as their potential applications in targeted therapy.

Dual-phase dual-energy CT in patients with lung cancer: assessment of the additional value of iodine quantification in lymph node therapy response

OBJECTIVES

To investigate the potential contribution of iodine uptake calculation from dual-phase dual-energy CT (DE-CT) for lymph node staging and therapy response monitoring in lung cancer patients.

METHODS

Retrospective analysis of 27 patients with non-small cell lung carcinoma (NSCLC), who underwent dual-phase DE-CT before and after chemotherapy, was performed. Iodine uptake (mg/mL) and total iodine uptake (mg) were calculated using prototype software in the early (arterial) and late (venous) post-contrast circulatory phase in 110 mediastinal lymph nodes. The arterial enhancement fraction (AEF) was calculated and compared with lymph node size and response to chemotherapy.

RESULTS

A significant difference of AEF was observed between enlarged (90.4%; 32.3-238.5%) and non-enlarged (72.7%; -37.5-237.5%) lymph nodes (p = 0.044) before treatment onset. A significantly different change of AEF in responding (decrease of 26.3%; p = 0.022) and non-responding (increase of 43.0%; p = 0.031) lymph nodes was demonstrated. A higher value of AEF before treatment was observed in lymph nodes with subsequent favourable response (88.6% vs. 77.7%; p = 0.122), but this difference did not reach statistical significance.

CONCLUSIONS

The dual-phase DE-CT examination with quantification of ratio of early and late post-contrast iodine uptake is a feasible and promising method for the functional evaluation of mediastinal lymph nodes including therapy response assessment.

KEY POINTS

• Dual-phase DE-CT is beneficial for mediastinal lymph node assessment in NSCLC. • Arterial to venous iodine uptake ratio was higher in enlarged lymph nodes. • Change of arterial enhancement fraction correlated to therapy response.

Perfusion CT imaging of colorectal cancer

Imaging plays an important role in the assessment of colorectal cancer, including diagnosis, staging, selection of treatment, assessment of treatment response, surveillance and investigation of suspected disease relapse. Anatomical imaging remains the mainstay for size measurement and structural evaluation; however, functional imaging techniques may provide additional insights into the tumour microenvironment. With dynamic contrast-enhanced CT techniques, iodinated contrast agent kinetics may inform on regional tumour perfusion, shunting and microvascular function and provide a surrogate measure of tumour hypoxia and angiogenesis. In colorectal cancer, this may be relevant for clinical practice in terms of tumour phenotyping, prognostication, selection of individualized treatment and therapy response assessment.

Multiparametric PET/CT-perfusion does not add significant additional information for initial staging in lung cancer compared with standard PET/CT

BACKGROUND

The purpose of this study was to assess the relationship of CT-perfusion (CTP), 18F-FDG-PET/CT and histological parameters, and the possible added value of CTP to FDG-PET/CT in the initial staging of lung cancer.

METHODS

Fifty-four consecutive patients (median age 65 years, 15 females, 39 males) with suspected lung cancer were evaluated prospectively by CT-perfusion scan and 18F-FDG-PET/CT scan. Overall, 46 tumors were identified. CTP parameters blood flow (BF), blood volume (BV), and mean transit time (MTT) of the tumor tissue were calculated. Intratumoral microvessel density (MVD) was assessed quantitatively. Differences in CTP parameters concerning tumor type, location, PET positivity of lymph nodes, TNM status, and UICC stage were analyzed. Spearman correlation analyses between CTP and 18F-FDG-PET/CT parameters (SUVmax, SUVmean, PETvol, and TLG), MVD, tumor size, and tumor stage were performed.

RESULTS

The mean BF (mL/100 mL min-1), BV (mL/100 mL), and MTT (s) was 35.5, 8.4, and 14.2, respectively. The BF and BV were lower in tumors with PET-positive lymph nodes (p = 0.02). However, the CTP values were not significantly different among the N stages. The CTP values were not different, depending on tumor size and location. No significant correlation was found between CTP parameters and MVD.

CONCLUSIONS

Overall, the CTP information showed only little additional information for the initial staging compared with standard FDG-PET/CT. Low perfusion in lung tumors might possibly be associated with metabolically active regional lymph nodes. Apart from that, both CTP and 18F-FDG-PET/CT parameter sets may reflect different pathophysiological mechanisms in lung cancer.

Functional imaging in lung cancer

Lung cancer represents an increasingly frequent cancer diagnosis worldwide. An increasing awareness on smoking cessation as an important mean to reduce lung cancer incidence and mortality, an increasing number of therapy options and a steady focus on early diagnosis and adequate staging have resulted in a modestly improved survival. For early diagnosis and precise staging, imaging, especially positron emission tomography combined with CT (PET/CT), plays an important role. Other functional imaging modalities such as dynamic contrast-enhanced CT (DCE-CT) and diffusion-weighted MR imaging (DW-MRI) have demonstrated promising results within this field. The purpose of this review is to provide the reader with a brief and balanced introduction to these three functional imaging modalities and their current or potential application in the care of patients with lung cancer.

Characterization of tumor heterogeneity using dynamic contrast enhanced CT and FDG-PET in non-small cell lung cancer

PURPOSE

Dynamic contrast-enhanced CT (DCE-CT) quantifies vasculature properties of tumors, whereas static FDG-PET/CT defines metabolic activity. Both imaging modalities are capable of showing intra-tumor heterogeneity. We investigated differences in vasculature properties within primary non-small cell lung cancer (NSCLC) tumors measured by DCE-CT and metabolic activity from FDG-PET/CT.

METHODS

Thirty three NSCLC patients were analyzed prior to treatment. FDG-PET/CT and DCE-CT were co-registered. The tumor was delineated and metabolic activity was segmented on the FDG-PET/CT in two regions: low (<50% maximum SUV) and high (≥50% maximum SUV) metabolic uptake. Blood flow, blood volume and permeability were calculated using a maximum slope, deconvolution algorithm and a Patlak model. Correlations were assessed between perfusion parameters for the regions of interest.

RESULTS

DCE-CT provided additional information on vasculature and tumor heterogeneity that was not correlated to metabolic tumor activity. There was no significant difference between low and high metabolic active regions for any of the DCE-CT parameters. Furthermore, only moderate correlations between maximum SUV and DCE-CT parameters were observed.

CONCLUSIONS

No direct correlation was observed between FDG-uptake and parameters extracted from DCE-CT. DCE-CT may provide complementary information to the characterization of primary NSCLC tumors over FDG-PET/CT imaging.

Dynamic volume perfusion CT in patients with lung cancer: baseline perfusion characteristics of different histological subtypes

OBJECTIVE

To evaluate dynamic volume perfusion CT (dVPCT) tumor baseline characteristics of three different subtypes of lung cancer in untreated patients.

MATERIALS AND METHODS

173 consecutive patients (131 men, 42 women; mean age 61 ± 10 years) with newly diagnosed lung cancer underwent dVPCT prior to biopsy. Tumor permeability, blood flow (BF), blood volume (BV) and mean transit time (MTT) were quantitatively assessed as well as tumor diameter and volume. Tumor subtypes were histologically determined and compared concerning their dVPCT results. dVPCT results were correlated to tumor diameter and volume.

RESULTS

Histology revealed adenocarcinoma in 88, squamous cell carcinoma in 54 and small cell lung cancer (SCLC) in 31 patients. Tumor permeability was significantly differing between adenocarcinoma, squamous cell carcinoma and SCLC (all p<0.05). Tumor BF and BV were higher in adenocarcinomathan in SCLC (p = 0.001 and p=0.0002 respectively). BV was also higher in squamous cell carcinoma compared to SCLC (p = 0.01). MTT was not differing between tumor subtypes. Regarding all tumors, tumor diameter did not correlate with any of the dVPCT parameters, whereas tumor volume was negatively associated with permeability, BF and BV (r = -0.22, -0.24, -0.24, all p<0.05). In squamous cell carcinoma, tumor diameter und volume correlated with BV (r = 0.53 and r = -0.40, all p<0.05). In SCLC, tumor diameter und volume correlated with MTT (r = 0.46 and r = 0.39, all p<0.05). In adenocarcinoma, no association between morphological and functional tumor characteristics was observed.

CONCLUSIONS

dVPCT parameters are only partially related to tumor diameter and volume and are significantly differing between lung cancer subtypes.

Multiparametric PET/CT in oncology

The standardized uptake value (SUV) and other measurements of tumour uptake of fluorodeoxyglucose (FDG) on positron emission tomography (PET) can potentially be supplemented by additional imaging parameters derived either from the PET images or from the computed tomography (CT) component of integrated PET/CT examinations including tumour size, CT attenuation, texture (reflecting tumour heterogeneity) and blood flow. This article illustrates the emerging benefits of such a multiparametric approach. Example benefits include greater diagnostic accuracy in characterization of adrenal masses achieved by using both the SUV and measured CT attenuation. Tumour size combined with the SUV can potentially improve the prognostic information available from PET/CT in oesophageal and lung cancer. However, greater improvements may be realized through using CT measurements of texture instead of size. Studies in breast and lung cancer suggest that combined PET/CT measurements of glucose metabolism and blood flow provide correlates for tumour proliferation and angiogenesis, respectively. These combined measurements can be utilized to determine vascular-metabolic phenotypes, which vary with tumour type. Uncoupling of blood flow and metabolism suggests a poor prognosis for larger more advanced tumours, high-grade lesions and tumours responding poorly to treatment. Vascular-metabolic imaging also has the potential to subclassify tumour response to treatment. The additional biomarkers described can be readily incorporated in existing FDG-PET examinations thereby improving the ability of PET/CT to depict tumour biology, characterize potentially malignant lesions, and assess prognosis and therapeutic response.