Evaluating early response of cervical cancer under concurrent chemo-radiotherapy by intravoxel incoherent motion MR imaging

Utility of interim apparent diffusion coefficient value in predicting treatment response among patients with locally advanced cervical cancer treated with radiotherapy

Background

For locally advanced cervical cancer (LACC), treatment response to radiotherapy (RT) can vary significantly even among those with the same stage classification of International Federation of Gynecology and Obstetrics (FIGO). This study investigated the value of ADC metric for forecasting end-of-treatment outcomes in LACC patients referred for RT.

Methods

Eighty patients with pathologically confirmed cervical squamous cell carcinoma with (SCC) were included in the research. Abdominal or pelvic MRI scans were conducted at least three times for all participants: before RT, three weeks after beginning of RT and approximately two months after RT was finalized. Calculated apparent diffusion coefficient (ADC) values of the LACC include: pre-ADC, interim-ADC, ΔADC and Δ%ADC. Based on Response Evaluation Criteria in Solid Tumors (RECIST) 1.1, subjects were calculated and subsequently categorized into good responders group (complete response) and poor responders group (progressive disease, stable disease or partial response).

Results

Compared to good-responders, subjects of poor-responder group showed significantly lower values of interim-ADC, ΔADC, and Δ%ADC (all P < 0.05). To distinguish between good and poor responders, the optimal cutoff values of interim-ADC, ΔADC, and Δ%ADC were determined to be 1.067 × 10-3 mm2/sec, 0.209 × 10-3 mm2/sec, and 30.74 % using the ROC curve, with corresponding sensitivities of 83.78 %, 86.49 %, 75.68 %, and specificities of 88.37 %, 86.49 %, 75.68 %, respectively. Multivariate logistic regression revealed that the baseline tumor diameter and interim-ADC were significant prognostic factors for treatment response with an odds ratio (OR) of 0.105 (95 % confidence interval [95 % CI] 0.018-0.616) for baseline tumor diameter and 42.896 (95 % CI 8.205-224.262) for interim-ADC.

Conclusion

The interim-ADC value and baseline tumor diameter surfaced as possible indicative factors for predicting the response to RT in patients with LACC.

Intravoxel incoherent motion magnetic resonance imaging to assess early tumor response to radiation therapy: Review and future directions

Early prediction of radiation response by imaging is a dynamic field of research and it can be obtained using a variety of noninvasive magnetic resonance imaging methods. Recently, intravoxel incoherent motion (IVIM) has gained interest in cancer imaging. IVIM carries both diffusion and perfusion information, making it a promising tool to assess tumor response. Here, we briefly introduced the basics of IVIM, reviewed existing studies of IVIM in various type of tumors during radiotherapy in order to show whether IVIM is a useful technique for an early assessment of radiation response. 31/40 studies reported an increase of IVIM parameters during radiotherapy compared to baseline. In 27 studies, this increase was higher in patients with good response to radiotherapy. Future directions including implementation of IVIM on MR-Linac and its limitation are discussed. Obtaining new radiologic biomarkers of radiotherapy response could open the way for a more personalized, biology-guided radiation therapy.

Quantitative analysis of superb microvascular imaging for monitoring tumor response to chemoradiotherapy in locally advanced cervical cancer

Objectives

As an ultrasound (US) image processing method, superb microvascular imaging (SMI) extracts and visualizes flow signals from vessels through advanced clutter suppression technology. We investigated the feasibility of SMI in monitoring treatment response in patients with locally advanced cervical cancer (LACC) undergoing chemoradiotherapy (CRT).

Methods

Forty-nine patients underwent CRT and received SMI examination at 3 time points: before therapy (baseline), 3 weeks during, and 1 month after CRT. The maximum tumor diameter (Dmax), vascularity index (VI), and their percentage changes (ΔDmax and ΔVI) were calculated. ΔDmax was compared with MRI results as the reference standard.

Results

Based on the MRI findings, 44 were classified as complete response (CR) group and 5 as partial response (PR) group. The Dmax and ΔDmax showed decrease in CR and PR groups at 3 weeks during CRT (P< 0.05), but no significant difference between the two groups (P > 0.05). Compared to the baseline, significant decrease in VI and ΔVI were observed at during and after treatment in the two groups (P< 0.05). Moreover, there were significant differences in VI and ΔVI at 3 weeks during CRT between the CR and PR groups (P< 0.05). ΔVI at 3 weeks during CRT showed a better predictive performance for responder prognosis than VI (AUC = 0.964, AUC = 0.950, respectively, P = 0.001), with a cut-off value of 41.6% yielding 100% sensitivity and 86.4% specificity.

Conclusions

The SMI parameters (VI and ΔVI) have potential for monitoring treatment response in LACC.

The histidine phosphatase LHPP: an emerging player in cancer

Cancers continue to have high incidence and mortality rates worldwide. Therefore, cancer control remains the main public health goal. Growing research evidence suggests that phospholysine phosphohistidine inorganic pyrophosphate phosphatase (LHPP) plays an important role in inhibiting tumor cell progression. It has been reported in the literature that LHPP is expressed at low levels in tumor tissues and cells and that patients with low LHPP expression have a poorer prognosis. Functional studies have shown that LHPP can inhibit tumor cell proliferation, metastasis, and apoptosis by affecting different target genes. In addition, researchers have used iDPP nanoparticles to deliver LHPP plasmids to treat tumors, demonstrating the great potential of LHPP plasmids for cancer therapy. In our review, we highlight the biological functions and important downstream target genes of LHPP in tumors, providing a theoretical basis for the treatment of human cancers. Although not thoroughly studied in terms of tumor mechanisms, LHPP still represents a promising and effective anticancer drug target.

Combining Intravoxel Incoherent Motion Diffusion Weighted Imaging and Texture Analysis for a Nomogram to Predict Early Treatment Response to Concurrent Chemoradiotherapy in Cervical Cancer Patients

This study aimed to predict early treatment response to concurrent chemoradiotherapy (CCRT) by combining intravoxel incoherent motion diffusion weighted imaging (IVIM-DWI) with texture analysis (TA) for cervical cancer patients and to develop a nomogram for estimating the risk of residual tumor. Ninty-three cervical cancer patients underwent conventional MRI and IVIM-DWI before CCRT. We conducted TA using T2WI. The patients were allocated to partial response (PR) and complete response (CR) groups on the basis of posttreatment MRI. Multivariate logistic regression analysis on IVIM-DWI parameters and texture features was employed to filter the independent predictors and construct the predictive nomogram. Its discrimination and calibration performances were estimated. Multivariate analysis on the IVIM-DWI parameters showed that D and f were independent predictors (OR = 4.029 and 0.889, resp.; p < 0.05). However, the multivariate analysis on the texture features indicated that GLCM-correlation, GLRLM-LRE, and GLSZM-ZE were independent predictors (OR = 43.789, 9.774, and 23.738, resp.;p < 0.05). The combination of IVIM-DWI parameters and texture features exhibited the highest predictive performance (AUC = 0.975). The nomogram to identify the patients with high-risk residual tumors exhibited an acceptable predictive performance and stability with a C-index of 0.953. Decision curve analysis demonstrated the clinical use of the nomogram. The results demonstrate that D, f, GLCM-correlation, GLRLM-LRE, and GLSZM-ZE were independent predictors for cervical cancer. The nomogram combining IVIM-DWI parameters and texture features makes it possible to identify cervical cancer patients at a high risk of residual tumor after CCRT.

Tumor Microenvironment Modifications Recorded With IVIM Perfusion Analysis and DCE-MRI After Neoadjuvant Radiotherapy: A Preclinical Study

PURPOSE

Neoadjuvant radiotherapy (NeoRT) improves tumor local control and facilitates tumor resection in many cancers. Some clinical studies demonstrated that both timing of surgery and RT schedule influence tumor dissemination, and subsequently patient overall survival. Previously, we developed a pre-clinical model demonstrating the impact of NeoRT schedule and timing of surgery on metastatic spreading. We report on the impact of NeoRT on tumor microenvironment by MRI.

METHODS

According to our NeoRT model, MDA-MB 231 cells were implanted in the flank of SCID mice. Tumors were locally irradiated (PXI X-Rad SmART) with 2x5Gy and then surgically removed at different time points after RT. Diffusion-weighted (DW) and Dynamic contrast enhancement (DCE) MRI images were acquired before RT and every 2 days between RT and surgery. IntraVoxel Incoherent Motion (IVIM) analysis was used to obtain information on intravascular diffusion, related to perfusion (F: perfusion factor) and subsequently tumor vessels perfusion. For DCE-MRI, we performed semi-quantitative analyses.

RESULTS

With this experimental model, a significant and transient increase of the perfusion factor F [50% of the basal value (n=16, p<0.005)] was observed on day 6 after irradiation as well as a significant increase of the WashinSlope with DCE-MRI at day 6 (n=13, p<0.05). Using immunohistochemistry, a significant increase of perfused vessels was highlighted, corresponding to the increase of perfusion in MRI at this same time point. Moreover, Tumor surgical resection during this peak of vascularization results in an increase of metastasis burden (n=10, p<0.05).

CONCLUSION

Significant differences in perfusion-related parameters (F and WashinSlope) were observed on day 6 in a neoadjuvant radiotherapy model using SCID mice. These modifications are correlated with an increase of perfused vessels in histological analysis and also with an increase of metastasis spreading after the surgical procedure. This experimental observation could potentially result in a way to personalize treatment, by modulating the time of surgery guided on MRI functional data, especially tumor perfusion.

Diffusion-weighted MRI to detect early response to chemoradiation in cervical cancer: A systematic review and meta-analysis

OBJECTIVE

Diffusion-weighted magnetic resonance imaging (DWI) has shown promise in predicting response to therapy in several malignancies. This systematic review and meta-analysis aimed to evaluate DWI in the prediction of response to treatment in patients with cervical cancer.

METHODS

A systematic search was conducted on PubMed, Web of Science, Cochrane and Google Scholar databases Studies that evaluated DWI and apparent diffusion coefficient (ADC) for response evaluation before, during and after treatment with a correlation to conventional response criteria were included. The primary endpoint was the mean ADC values of cervical cancer at these timepoints. The Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) was used to assess the quality of the studies.

RESULTS

Nine studies, comprising 270 patients, were included. Pre-treatment ADC values showed no correlation with eventual response. However, in our meta-analysis, there was a significant correlation with early treatment ADC values obtained within the first 3 weeks of therapy and response, as well as a significant correlation with the percentage change in ADC (ΔADC) and response. In addition, the pooled mean ΔADC percentage was also significantly higher in responders than in non-responders (49.7% vs 19.7%, respectively, p = 0.016).

CONCLUSION

DWI shows potential as a biomarker of early treatment response in patients with cervical carcinoma. Use of the change in ADC particularly within the first 3 weeks of therapy seems to be predictive of response and may serve as a suitable marker in the determination of early response.

Improved unsupervised physics-informed deep learning for intravoxel incoherent motion modeling and evaluation in pancreatic cancer patients

PURPOSE

Earlier work showed that IVIM-NETorig , an unsupervised physics-informed deep neural network, was faster and more accurate than other state-of-the-art intravoxel-incoherent motion (IVIM) fitting approaches to diffusion-weighted imaging (DWI). This study presents a substantially improved version, IVIM-NEToptim , and characterizes its superior performance in pancreatic cancer patients.

METHOD

In simulations (signal-to-noise ratio [SNR] = 20), the accuracy, independence, and consistency of IVIM-NET were evaluated for combinations of hyperparameters (fit S0, constraints, network architecture, number of hidden layers, dropout, batch normalization, learning rate), by calculating the normalized root-mean-square error (NRMSE), Spearman's ρ, and the coefficient of variation (CVNET ), respectively. The best performing network, IVIM-NEToptim was compared to least squares (LS) and a Bayesian approach at different SNRs. IVIM-NEToptim 's performance was evaluated in an independent dataset of 23 patients with pancreatic ductal adenocarcinoma. Fourteen of the patients received no treatment between two repeated scan sessions and nine received chemoradiotherapy between the repeated sessions. Intersession within-subject standard deviations (wSD) and treatment-induced changes were assessed.

RESULTS

In simulations (SNR = 20), IVIM-NEToptim outperformed IVIM-NETorig in accuracy (NRMSE(D) = 0.177 vs 0.196; NMRSE(f) = 0.220 vs 0.267; NMRSE(D*) = 0.386 vs 0.393), independence (ρ(D*, f) = 0.22 vs 0.74), and consistency (CVNET (D) = 0.013 vs 0.104; CVNET (f) = 0.020 vs 0.054; CVNET (D*) = 0.036 vs 0.110). IVIM-NEToptim showed superior performance to the LS and Bayesian approaches at SNRs < 50. In vivo, IVIM-NEToptim showed significantly less noisy parameter maps with lower wSD for D and f than the alternatives. In the treated cohort, IVIM-NEToptim detected the most individual patients with significant parameter changes compared to day-to-day variations.

CONCLUSION

IVIM-NEToptim is recommended for accurate, informative, and consistent IVIM fitting to DWI data.

Adaptive Radiotherapy in the Management of Cervical Cancer: Review of Strategies and Clinical Implementation

The complex and varied motion of the cervix-uterus target during external beam radiotherapy (EBRT) underscores the clinical benefits afforded by adaptive radiotherapy (ART) techniques. These gains have already been realised in the implementation of image-guided adaptive brachytherapy, where adapting to anatomy at each fraction has seen improvements in clinical outcomes and a reduction in treatment toxicity. With regards to EBRT, multiple adaptive strategies have been implemented, including a personalised internal target volume, offline replanning and a plan of the day approach. With technological advances, there is now the ability for real-time online ART using both magnetic resonance imaging and computed tomography-guided imaging. However, multiple challenges remain in the widespread dissemination of ART. This review investigates the ART strategies and their clinical implementation in EBRT delivery for cervical cancer.

Noninvasive assessment of endometrial fibrosis in patients with intravoxel incoherent motion MR imaging

Recently, few noninvasive methods have been reported to evaluate endometrial fibrosis. Our study was to investigate the feasibility of intravoxel incoherent motion (IVIM) MR imaging in the detection of endometrial fibrosis in patients with intrauterine injury. 30 patients with hysteroscopy-confirmed endometrial fibrosis and 28 healthy women were enrolled to undergo MR examination including the IVIM sequence. Endometrial thickness (ET); apparent diffusion coefficient (ADC); and IVIM parameters, including pure diffusion coefficient (D), pseudodiffusion coefficient (D*) and vascular fraction (f) were evaluated. A multivariable model combing ADC, D, and f values using binary logistic regression analysis was built to diagnose endometrial fibrosis. Endometrial fibrosis patients demonstrated lower endometrial ADC, D, f values and ET (all p < 0.05). The multivariable model, ADC, D, f values and ET performed well in diagnosing endometrial fibrosis with AUC of 0.979, 0.965, 0.920, 0.901 and 0.833, respectively. The multivariable model revealed a better diagnostic accuracy than D, f and ET (all p < 0.05). Although ADC achieved a better diagnostic value than ET (z = 2.082, p < 0.05), no difference in AUC was shown among ADC, D, and f (all p > 0.05); between ET and D (p > 0.05); and between ET and f (p > 0.05). The reproducibility of ADC, D, f and D* values in patients with endometrial fibrosis and healthy women were good to excellent (ICC: 0.614-0.951). IVIM parameters exhibit promising potential to serve as imaging biomarkers in the noninvasive assessment of endometrial fibrosis.

Reproducibility of radiomics features derived from intravoxel incoherent motion diffusion-weighted MRI of cervical cancer

BACKGROUND

The reproducibility of intravoxel incoherent motion (IVIM)-based radiomics studies in humans has not been reported.

PURPOSE

To determine the inter- and intra-observer variability on the reproducibility of IVIM-based radiomics features in cervical cancer (CC).

MATERIAL AND METHODS

The IVIM images of 25 patients with CC were retrospectively collected. Based on the high-resolution T2-weighted images, the regions of interest (ROIs) were independently delineated twice in diffusion-weighted images at a b value of 1000 s/mm² (interval time was one month) by two radiologists. This was done at the largest transversal cross-sections of the tumors. The ROI was subsequently used in apparent diffusion coefficient (ADC), true diffusion coefficient (D), pseudo-diffusion coefficient (D*), and perfusion fraction (f) maps derived from IVIM images. In total, 105 radiomics features were then finally extracted from the IVIM-derived maps. The inter- and intra-observer reproducibility of IVIM-derived features was then evaluated using the intraclass correlation coefficient.

RESULTS

Inter- and intra-observer variability affected the reproducibility of radiomics features. D* map had 100% and 95% reproducible features, ADC map had 89% and 93%, D map had 97% and 86%, while f map had 54% and 62% reproducible features with good to excellent reliability in the intra-observer analysis. Similarly, D* map had 90% and 94%, ADC map had 85% and 70%, D map had 81% and 78%, while f map had 41% and 93% reproducible features with good to excellent reliability in the inter-observer analysis.

CONCLUSION

Inter- and intra-observer variability can affect radiomics analysis. Cognizant to this, multicenter studies should pay more attention to intra- and inter-observer variability.

Association between IVIM parameters and treatment response in locally advanced squamous cell cervical cancer treated by chemoradiotherapy

OBJECTIVE

To examine the associations of intravoxel incoherent motion (IVIM) parameters with treatment response in cervical cancer following concurrent chemoradiotherapy (CCRT).

MATERIALS AND METHODS

Forty-five patients, median age of 58 years (range: 28-82), with pre-CCRT and post-CCRT MRI, were retrospectively analysed. The IVIM parameters pure diffusion coefficient (D) and perfusion fraction (f) were estimated using the full b-value distribution (BVD) as well as an optimised subsample BVD. Dice similarity coefficient (DSC) and intraclass correlation coefficient (ICC) were used to measure observer repeatability in tumour delineation at both time points. Treatment response was determined by the response evaluation criteria in solid tumour (RECIST) 1.1 between MRI examinations. Mann-Whitney U tests were used to test for significant differences in IVIM parameters between treatment response groups.

RESULTS

Pre-CCRT tumour delineation repeatability was good (DSC = 0.81) while post-CCRT delineation repeatability was moderate (DSC = 0.67). Values of D and f had good repeatability at both time points (ICC > 0.80). Pre-CCRT f estimated using the full BVD and optimised subsample BVD were found to be significantly higher in patients with partial response compared to those with stable disease or disease progression (p = 0.01 and 95% CI = -0.02-0.00 for both cases).

CONCLUSION

Pre-CCRT f was associated with treatment response in cervical cancer with good observer repeatability. Similar discriminative ability was also observed in estimated pre-CCRT f from an optimised subsample BVD.

KEY POINTS

• Pre-treatment tumour delineation and IVIM parameters had good observer repeatability. • Post-treatment tumour delineation was worse than at pre-treatment, but IVIM parameters retained good ICC. • Pre-treatment perfusion fraction estimated from all b-values and an optimised subsample of b-values were associated with treatment response.

Quantitative Magnetic Resonance Imaging for Biological Image-Guided Adaptive Radiotherapy

MRI-guided radiotherapy systems have the potential to bring two important concepts in modern radiotherapy together: adaptive radiotherapy and biological targeting. Based on frequent anatomical and functional imaging, monitoring the changes that occur in volume, shape as well as biological characteristics, a treatment plan can be updated regularly to accommodate the observed treatment response. For this purpose, quantitative imaging biomarkers need to be identified that show changes early during treatment and predict treatment outcome. This review provides an overview of the current evidence on quantitative MRI measurements during radiotherapy and their potential as an imaging biomarker on MRI-guided radiotherapy systems.

A comparative study of methods for determining Intravoxel incoherent motion parameters in cervix cancer

Background

To compare different fitting methods for determining IVIM (Intravoxel Incoherent Motion) parameters and to determine whether the use of different IVIM fitting methods would affect differentiation of cervix cancer from normal cervix tissue.

Methods

Diffusion-weighted echo-planar imaging of 30 subjects was performed on a 3.0 T scanner with b-values of 0, 30, 100, 200, 400, 1000 s/mm². IVIM parameters were estimated using the segmented (two-step) fitting method and by simultaneous fitting of a bi-exponential function. Segmented fitting was performed using two different cut-off b-values (100 and 200 s/mm²) to study possible variations due to the choice of cut-off. Friedman’s test and Student’s t-test were respectively used to compare IVIM parameters derived from different methods, and between cancer and normal tissues.

Results

No significant difference was found between IVIM parameters derived from the segmented method with b-value cutoff of 200 s/mm² and the simultaneous fitting method (P>0.05). Tissue diffusivity (D) and perfusion fraction (f) were significantly lower in cervix cancer than normal tissue (P< 0.05).

Conclusions

IVIM parameters derived using fitting methods with small cutoff b-values could be different, however, the segmented method with b-value cutoff of 200 s/mm² are consistent with the simultaneous fitting method and both can be used to differentiate between cervix cancer and normal tissue.

Endostar Rebuilding Vascular Homeostasis and Enhancing Chemotherapy Efficacy in Cervical Cancer Treatment

Background

The incidence rate of cervical cancer is the highest in the reproductive tract and is not sensitive to chemotherapy. An appropriate amount of anti-angiogenic agents can reconstruct tumor blood vessels in a short period of time and form vascular homeostasis, increase the function of blood vessel perfusion and reverse the multidrug resistance of chemotherapy, which is also called “vascular normalization.” Endostar (a recombinant human endostatin) was developed by China and as a multi-target anti-angiogenesis agent. Many reports about endostar involved the treatment of non-small cell lung cancer, fewer reports are on cervical cancer.

Purpose

To determine whether endostar can rebuild tumor vascular homeostasis and enhance chemotherapy effects for patients with cervical cancer.

Methods

In this study, the patients with cervical cancer within stage IIB2 were selected, endostar combined with cisplatin+paclitaxel neoadjuvant chemotherapy (NACT) before radical surgical operation was adopted, patients outcome and adverse reaction were followed up. The changes of tumor vascular structure and perfusion function before and after endostar given were evaluated by histopathology and dynamic contrast-enhanced magnetic resonance imaging (DEC-MRI). VEGF-Notch signal pathway was detected for the regulating mechanism of vascular proliferation in different groups. GraphPad Prism 6 software was used for statistical analysis of the study results.

Results

Endostar enhanced the short-term (2 year) overall survival (OS), progression-free survival (PFS) rates for cervical cancer patients. All the same, endostar increased long-term (5 year) OS for cervical cancer patients. Endostar therapy exhibited with mild adverse reaction. MRI showed endostar+NACT further reduce tumor volume than NACT alone. The parameters of Ktrans, Ve for DEC-MRI in endostar group exhibited obviously increase than NACT group. Tumor vascular maturation index α-SMA/CD31 in endostar group increased obviously than NACT group, correspondingly Ki67 staining for tumor proliferative rates, lymphovascular space invasion in endostar group further declined than NACT group. The genes and proteins expression of VEGFR2, Notch1, Notch4, Dll4, Jag1 were obviously downregulated in endostar group comparing to NACT group.

Conclusion

Endostar restored vascular homeostasis in cervical cancer temporarily, enhanced chemotherapeutic agents effects in cervical cancer, increased patient OS ratio. Endostar+NACT treatment may provide a new target therapy for cervical cancer.

Point your SmartPhone at the code above. If you have a QR code reader the video abstract will appear. Or use:

https://youtu.be/XpGkysB2oaw

Association between MRI histogram features and treatment response in locally advanced cervical cancer treated by chemoradiotherapy

OBJECTIVE

To examine the associations of histogram features of T2-weighted (T2W) images and apparent diffusion coefficient (ADC) with treatment response in locally advanced cervical cancer (LACC) following concurrent chemoradiotherapy (CCRT).

MATERIALS AND METHODS

Fifty-eight patients who underwent a 4-week CCRT regimen with MRI prior to treatment (pre-CCRT) and after treatment (post-CCRT) were retrospectively analysed. Histogram features were calculated from volumes of interest (VOIs) from one radiologist on T2W images and ADC maps. VOIs from two radiologists were used to assess observer repeatability in delineation and feature values at both time-points with the Dice similarity coefficient (DSC) and intraclass correlation coefficient (ICC). Treatment response was defined as a 90% reduction in tumour volume. Paired Mann-Whitney U tests were used to determine if features changed significantly between examinations. Two-sample Mann-Whitney U tests were used to identify features that were significantly different between response groups. Receiver operating characteristic (ROC) analysis was done on significantly different MRI features between treatment response groups.

RESULTS

Pre-CCRT delineation and feature repeatability were generally good (DSC > 0.700; ICC > 0.750). Post-CCRT repeatability was low (DSC < 0.700; ICC < 0.750), but ADC mean and percentiles retained good ICC scores. All features, except for T2W_Kurtosis, significantly changed between examinations. Post-CCRT ADC₅₀ was the only feature that demonstrated both good observer variability and significant differences between treatment response groups (p = 0.036) and had an AUC of 0.701 with a cut-off of 1.357 × 10^-6 mm²/s.

CONCLUSION

ADC and T2W histogram features could be used to track changes in LACC tumours undergoing CCRT. Post-CCRT ADC₅₀ was associated with treatment response with good observer repeatability.

KEY POINTS

• Pre-treatment tumour delineation and histogram feature values had good observer repeatability, while these were less repeatable at post-treatment. • MRI histogram analysis could be used to track changes in the tumour as it undergoes concurrent chemoradiotherapy. • Post-treatment median ADC was associated with treatment response and had good repeatability.

Potentialities of multi-b-values diffusion-weighted imaging for predicting efficacy of concurrent chemoradiotherapy in cervical cancer patients

BACKGROUND

To testify whether multi-b-values diffusion-weighted imaging (DWI) can be used to ultra-early predict treatment response of concurrent chemoradiotherapy (CCRT) in cervical cancer patients and to assess the predictive ability of concerning parameters.

METHODS

Fifty-three patients with biopsy proved cervical cancer were retrospectively recruited in this study. All patients underwent pelvic multi-b-values DWI before and at the 3rd day during treatment. The apparent diffusion coefficient (ADC), true diffusion coefficient (D_slow), perfusion-related pseudo-diffusion coefficient (D_fast), perfusion fraction (f), distributed diffusion coefficient (DDC) and intravoxel diffusion heterogeneity index(α) were generated by mono-exponential, bi-exponential and stretched exponential models. Treatment response was assessed based on Response Evaluation Criteria in Solid Tumors (RECIST v1.1) at 1 month after the completion of whole CCRT. Parameters were compared using independent t test or Mann-Whitney U test as appropriate. Receiver operating characteristic (ROC) curves was used for statistical evaluations.

RESULTS

ADC-T0 (p = 0.02), D_slow-T0 (p <  0.01), DDC-T0 (p = 0.03), ADC-T1 (p <  0.01), D_slow-T1 (p <  0.01), ΔADC (p = 0.04) and Δα (p <  0.01) were significant lower in non-CR group patients. ROC analyses showed that ADC-T1 and Δα exhibited high prediction value, with area under the curves of 0.880 and 0.869, respectively.

CONCLUSIONS

Multi-b-values DWI can be used as a noninvasive technique to assess and predict treatment response in cervical cancer patients at the 3rd day of CCRT. ADC-T1 and Δα can be used to differentiate good responders from poor responders.

MicroRNA‑15a‑5p‑targeting oncogene YAP1 inhibits cell viability and induces cell apoptosis in cervical cancer cells

MicroRNAs (miRNAs) have been reported to have important regulatory roles in the progression of several types of cancer, including cervical cancer (CC). However, the biological roles and regulatory mechanisms of miRNAs in CC remain to be fully elucidated. The aim of the present study was to examine the functions of miRNAs in CC and the possible mechanisms. Using a microarray, it was identified that miRNA-15a-5p (miR-15a-5p) was one of the most down-regulated miRNAs in CC tissues compared with adjacent noncancerous tissues. The low expression of miR-15a-5p was observed in CC tumor tissues with distant metastasis and in CC cell lines. In addition, the effects of miR-15a-5p upregulation on cell viability, apoptosis, invasion and migration of CC cells were investigated using CCK-8, flow cytometry, Transwell and wound healing assays, respectively. It was demonstrated that upregulation of miR-15a-5p significantly suppressed the viability, migration and invasion, and promoted the apoptosis of SiHa and C-33A cells. Furthermore, yes-associated protein 1 (YAP1), a well-known oncogene, was confirmed to be directly targeted by miR-15a-5p and was found to be negatively regulated by miR-15a-5p. Further correlation analysis indicated that miR-15a-5p expression was negatively correlated with YAP1 expression in CC tissues. Notably, overexpression of YAP1 abrogated the tumor suppressive effects of miR-15a-5p in CC cells. Taken together, these present findings indicated that the miR-15a-5p/YAP1 axis may provide a novel strategy for the clinical treatment of CC.

The invasion status of lymphovascular space and lymph nodes in cervical cancer assessed by mono-exponential and bi-exponential DWI-related parameters

AIM

To investigate whether mono-exponential and bi-exponential diffusion-weighted imaging (DWI)-related parameters of the primary tumour can evaluate the status of lymphovascular space invasion (LVSI) and lymph node metastasis (LNM) in patients with cervical carcinoma preoperatively.

MATERIALS AND METHODS

Eighty patients with cervical carcinoma were enrolled, who underwent preoperative multi b-value DWI and radical hysterectomy. They were classified into LVSI(+) versus LVSI(-) and LNM(+) versus LNM(-) according to postoperative pathology. The apparent diffusion coefficient (ADC), pure molecular diffusion (D), pseudo-diffusion coefficient (D∗), and perfusion fraction (f) were calculated from the whole tumour (__whole) and tumour margin (__margin). All parameters were compared between LVSI(+) and LVSI(-) and between LNM(+) and LNM(-). Logistic regression analysis and receiver operating characteristic (ROC) curve analysis were performed to evaluate the diagnostic performance of these parameters.

RESULTS

f__margin and D∗__whole showed significant differences in differentiating LVSI(+) from LVSI(-) tumours (p=0.002, 0.008, respectively), while LNM(+) tumours presented with significantly higher ADC__margin than that of LNM(-) tumours (p=0.009). The other parameters were not independent related factors with the status of LVSI or LNM according to logistic regression analysis (p>0.05). The area under the ROC curve of f__margin combined with D∗__whole in discriminating LVSI(+) from LVSI(-) was 0.826 (95% confidence interval [CI]: 0.691-0.961), while ADC__margin in differentiating LNM(+) from LNM(-) was 0.788 (95% CI: 0.648-0.928).

CONCLUSIONS

The parameters generated from mono-exponential and bi-exponential DWI of the primary cervical carcinoma could help discriminate its status regarding LVSI (f__margin and D∗__whole) and LNM (ADC__margin).

Multiple mathematical models of diffusion-weighted imaging for endometrial cancer characterization: Correlation with prognosis-related risk factors

PURPOSE

To investigate mono-exponential, bi-exponential, and stretched-exponential models of diffusion-weighted imaging (DWI) for evaluation of prognosis-related risk factors of endometrial cancer (EC).

METHOD

Sixty-one consecutive patients with EC who preoperatively underwent pelvic MRI with multiple b value DWI between September 2016 and May 2018 were enrolled. The apparent-diffusion-coefficient (ADC), bi-exponential model parameters (D, D* and f) and stretched-exponential model parameters (DDC and α) were measured and compared to analyze the following prognosis-related risk factors confirmed by pathology: histological grade, depth of myometrial invasion, cervical stromal infiltration (CSI) and lymphovascular invasion (LVSI). A stepwise multilvariate logistic regression and the receiver operating characteristic (ROC) curves were performed for further statistical analysis.

RESULTS

Lower ADC, D, f, and DDC were observed in tumor with high grade compared with a low-grade group, and the largest area under curve (AUC) was obtained when combining f and DDC values. ADC, D, f, DDC, and α were significantly different in patients with deep myometrial invasion (DMI) compared to those without DMI; the combination of f, DDC and α showed the highest AUC. Significantly different ADC and f were found between patients' presence and absence CSI; the f values showed the highest diagnostic performance with an AUC of 0.825. Regarding the LVSI, ADC, D*, f, and DDC were significantly lower in tumors with LVSI compared to those without LVSI; the combination of f and DDC showed the largest AUC.

CONCLUSION

Multiple mathematical DWI models are a useful approach for the prediction of prognosis-related risk factors in EC.

Quantitative imaging for radiotherapy purposes

Quantitative imaging biomarkers show great potential for use in radiotherapy. Quantitative images based on microscopic tissue properties and tissue function can be used to improve contouring of the radiotherapy targets. Furthermore, quantitative imaging biomarkers might be used to predict treatment response for several treatment regimens and hence be used as a tool for treatment stratification, either to determine which treatment modality is most promising or to determine patient-specific radiation dose. Finally, patient-specific radiation doses can be further tailored to a tissue/voxel specific radiation dose when quantitative imaging is used for dose painting. In this review, published standards, guidelines and recommendations on quantitative imaging assessment using CT, PET and MRI are discussed. Furthermore, critical issues regarding the use of quantitative imaging for radiation oncology purposes and resultant pending research topics are identified.

B-Value Optimization in the Estimation of Intravoxel Incoherent Motion Parameters in Patients with Cervical Cancer

OBJECTIVE

This study aimed to find the optimal number of b-values for intravoxel incoherent motion (IVIM) imaging analysis, using simulated and in vivo data from cervical cancer patients.

MATERIALS AND METHODS

Simulated data were generated using literature pooled means, which served as reference values for simulations. In vivo data from 100 treatment-naïve cervical cancer patients with IVIM imaging (13 b-values, scan time, 436 seconds) were retrospectively reviewed. A stepwise b-value fitting algorithm calculated optimal thresholds. Feed forward selection determined the optimal subsampled b-value distribution for biexponential IVIM fitting, and simplified IVIM modeling using monoexponential fitting was attempted. IVIM parameters computed using all b-values served as reference values for in vivo data.

RESULTS

In simulations, parameters were accurately estimated with six b-values, or three b-values for simplified IVIM, respectively. In vivo data showed that the optimal threshold was 40 s/mm² for patients with squamous cell carcinoma and a subsampled acquisition of six b-values (scan time, 198 seconds) estimated parameters were not significantly different from reference parameters (individual parameter error rates of less than 5%). In patients with adenocarcinoma, the optimal threshold was 100 s/mm², but an optimal subsample could not be identified. Irrespective of the histological subtype, only three b-values were needed for simplified IVIM, but these parameters did not retain their discriminative ability.

CONCLUSION

Subsampling of six b-values halved the IVIM scan time without significant losses in accuracy and discriminative ability. Simplified IVIM is possible with only three b-values, at the risk of losing diagnostic information.

Performing IVIM-DWI using the multifunctional nanosystem for the evaluation of the antitumor microcirculation changes

OBJECTIVES

There is a controversy about the D* and f values of intravoxel incoherent motion diffusion-weighted imaging (IVIM-DWI) for mid- and long-term efficacy monitoring of tumor blood perfusion. To monitor the antitumor efficacy of the F/A-PLGA@DOX/SPIO nanosystem via IVIM-DWI and to explore the value of parameters pseudo-diffusion (D*) and fraction of pseudo-diffusion (f) for evaluating therapeutic effect in non-small cell lung cancer (NSCLC).

MATERIALS AND METHODS

Thirty-six A549 tumor-bearing mice were divided randomly into three groups (each n = 12). Group 1 (G1) was injected with saline (the control group). Group 2 (G2) and group 3(G3) were injected with DOX and F/A-PLGA@DOX/SPIO, respectively. Each group underwent IVIM-DWI scanning at baseline and 3, 14, 21, and 28 days after treatment. D* and f values were derived using GE AW 4.5 post-processing station. All mice were sacrificed for pathological examination.

RESULTS

The D* value of all three groups showed an upward trend, with the highest increase in G1 and the lowest in G3. Conversely, the f value of all groups trended to decrease within 7 days, of which G3 showed the most significant decline. Immunohistochemical staining revealed that vascular endothelial growth factor (VEGF)-positive staining rate and the microvessel density (MVD) of the tumors in G3 were significantly lower than those of the other groups (P < 0.05). The D* and f values were significantly and positively correlated to CD31 (r = 0.654, P < 0.001; r = 0.712, P < 0.001) and VEGF (r = 0.694, P < 0.001; r = 0.664, P < 0.001).

CONCLUSION

IVIM-DWI-derived parameters D* and f are valuable indicators for the evaluation of the antitumor microcirculation changes of multifunctional nanosystem.

The transformation of radiation oncology using real-time magnetic resonance guidance: A review

Radiation therapy (RT) is an essential component of effective cancer care and is used across nearly all cancer types. The delivery of RT is becoming more precise through rapid advances in both computing and imaging. The direct integration of magnetic resonance imaging (MRI) with linear accelerators represents an exciting development with the potential to dramatically impact cancer research and treatment. These impacts extend beyond improved imaging and dose deposition. Real-time MRI-guided RT is actively transforming the work flows and capabilities of virtually every aspect of RT. It has the opportunity to change entirely the delivery methods and response assessments of numerous malignancies. This review intends to approach the topic of MRI-based RT guidance from a vendor neutral and international perspective. It also aims to provide an introduction to this topic targeted towards oncologists without a speciality focus in RT. Speciality implications, areas for physician education and research opportunities are identified as they are associated with MRI-guided RT. The uniquely disruptive implications of MRI-guided RT are discussed and placed in context. We further aim to describe and outline important future changes to the speciality of radiation oncology that will occur with MRI-guided RT. The impacts on RT caused by MRI guidance include target identification, RT planning, quality assurance, treatment delivery, training, clinical workflow, tumour response assessment and treatment scheduling. In addition, entirely novel research areas that may be enabled by MRI guidance are identified for future investigation.

Multiparametric PET/MR (PET and MR-IVIM) for the evaluation of early treatment response and prediction of tumor recurrence in patients with locally advanced cervical cancer

OBJECTIVES

To assess the value of ¹⁸F-FDG PET and MR-IVIM parameters before and during concurrent chemoradiotherapy (CCRT) for evaluating early treatment response and predicting tumor recurrence in patients with locally advanced cervical cancer (LACC) using a hybrid PET/MR scanner.

METHODS

Fifty-one patients with LACC underwent pelvic PET/MR scans with an IVIM sequence at two time-points (pretreatment [pre] and midtreatment [mid]). Pre- and mid-PET parameters (SUV_max, MTV, TLG) and IVIM parameters (D, F, D*) and their percentage changes (Δ%SUV_max, Δ%MTV, Δ%TLG, Δ%D, Δ%F, Δ%D*) were calculated. We selected independent imaging parameters and built a combined prediction model incorporating imaging parameters and clinicopathological risk factors. The performance of the combinative evaluation for tumor early shrinkage rates (TESR) and the prediction model for tumor recurrence was assessed.

RESULTS

Thirty-two patients were classified into the good response (GR) group with TESR ≥ 50%, and 19 patients were categorized into the poor response (PR) group with TESR < 50%. Δ%D (p = 0.013) and Δ%F (p = 0.006) are independently related to TESR with superior combined diagnostic ability (AUC = 0.901). Pre-TLG, Δ%D, and suspicious lymph node metastasis (SLNM) were selected for the construction of the combined prediction model. The model for identifying the patients with high risk of tumor recurrence reached a moderate predictive ability and good stability with c-index of 0.764 (95% CI, 0.672-0.855).

CONCLUSION

The combined prediction model based on pretreatment PET metabolic parameter (pre-TLG), IVIM-D percentage changes, and LNs status provides great potential to identify the LACC patients with high risk of recurrence at early stage of CCRT.

KEY POINTS

• PET/MR plus IVIM offers various complementary information for LACC. • IVIM-D and IVIM-F percentage changes are independently related to tumor early shrinkage rates. • The combined prediction model can help identify the LACC patients with high risk of tumor recurrence.

Radiomic analysis for pretreatment prediction of response to neoadjuvant chemotherapy in locally advanced cervical cancer: A multicentre study

BACKGROUND

We aimed to investigate whether pre-therapeutic radiomic features based on magnetic resonance imaging (MRI) can predict the clinical response to neoadjuvant chemotherapy (NACT) in patients with locally advanced cervical cancer (LACC).

METHODS

A total of 275 patients with LACC receiving NACT were enrolled in this study from eight hospitals, and allocated to training and testing sets (2:1 ratio). Three radiomic feature sets were extracted from the intratumoural region of T1-weighted images, intratumoural region of T2-weighted images, and peritumoural region of T2-weighted images before NACT for each patient. With a feature selection strategy, three single sequence radiomic models were constructed, and three additional combined models were constructed by combining the features of different regions or sequences. The performance of all models was assessed using receiver operating characteristic curve.

FINDINGS

The combined model of the intratumoural zone of T1-weighted images, intratumoural zone of T2-weighted images,and peritumoural zone of T2-weighted images achieved an AUC of 0.998 in training set and 0.999 in testing set, which was significantly better (p < .05) than the other radiomic models. Moreover, no significant variation in performance was found if different training sets were used.

INTERPRETATION

This study demonstrated that MRI-based radiomic features hold potential in the pretreatment prediction of response to NACT in LACC, which could be used to identify rightful patients for receiving NACT avoiding unnecessary treatment.

Strain elastography as an early predictor of long-term prognosis in patients with locally advanced cervical cancers treated with concurrent chemoradiotherapy

OBJECTIVE

To explore the value of strain elastography as an early predictor of long-term prognosis in patients with locally advanced cervical cancers treated with concurrent chemoradiotherapy (CCRT).

METHODS

Strain elastography examinations were performed on 45 patients with locally advanced cervical cancers at 3 time points: prior to CCRT, and at 1 and 2 weeks after the start of CCRT. The maximum tumor diameter (D_max), strain ratio (SR), and their percentage changes (ΔD_max and ΔSR) were calculated to predict long-term prognosis. Based on the results of physical examinations, Papanicolaou test, and pelvic magnetic resonance imaging, we classified patients into two groups: responders (complete remission) and non-responders (sustained disease, recurrence, or death).

RESULTS

After a median follow-up of 30 months (range, 12-36 months), 36 of 45 (80%) patients were disease free. The D_max as well as ΔD_max at 2 weeks during CCRT was able to predict the responder outcomes, with an area-under-the-curve (AUC) of 0.733 and 0.731, respectively. Furthermore, significant differences in SR and ΔSR at 1 and 2 weeks during therapy were shown between the responder and non-responder groups (all p < 0.05), and ΔSR at 2 weeks during CCRT presented with the highest AUC (0.91), yielding 88.9% sensitivity and 88.9% specificity with a selected cutoff value.

CONCLUSIONS

Strain elastography may be useful as an early predictor of long-term outcomes after CCRT for patients with cervical cancer.

KEY POINTS

• The D _maxas well as ΔD _maxat 2 weeks during CCRT can predict the responder outcomes. • The elastography parameters (SR and ΔSR) exhibited predictive values of favorable response after therapy initiation. • ΔSR at 2 weeks during CCRT held the best predictive value for the responder outcomes.

Designing multifunctional cancer-targeted nanosystem for magnetic resonance molecular imaging-guided theranostics of lung cancer

The integration of diagnosis and therapy is an effective way to improve therapeutic effects for cancer patients, which has acquired widely attentions from researchers. Herein, a multifunctional drug-loaded nanosystem (F/A-PLGA@DOX/SPIO) has been designed and synthesized to reduce the side effects of traditional chemotherapy drugs and realize simultaneous tumor diagnosis and treatment. The surface modification of folic acid (FA) and activatable cell-penetrating peptide (ACPP) endows the nanosystem with excellent cancer targeting capabilities, thus reducing toxicity to normal organs. Besides, the F/A-PLGA@DOX/SPIO nanosystem can serve as an excellent magnetic resonance imaging (MRI) T2-negative contrast agent. More importantly, according to in vitro experiments, the F/A-PLGA@DOX/SPIO nanosystem can promote the overproduction of reactive oxygen species (ROS) within A549 lung cancer cells, inducing cell apoptosis, greatly enhancing the antineoplastic effect. Furthermore, with the help of MRI technology, the targeting imaging of the F/A-PLGA@DOX/SPIO nanosystem within tumors and the dynamic monitoring of medicine efficacy can be realized. Therefore, this study provided a multifunctional drug-loaded F/A-PLGA@DOX/SPIO targeted nanosystem for magnetic resonance molecular imaging-guided theranostics, which has excellent potential for the application in tumor diagnosis and therapy.

microRNA-141-3p fosters the growth, invasion, and tumorigenesis of cervical cancer cells by targeting FOXA2

microRNA (miR)-141-3p has context-dependent effects on tumor progression. In this study, we attempted to explore the expression and function of miR-141-3p in cervical cancer. We found that miR-141-3p expression was significantly increased in cervical cancer specimens relative to normal cervical tissues. Moreover, miR-141-3p levels were associated with tumor size and lymph node metastasis status. Ectopic expression of miR-141-3p significantly increased cervical cancer cell proliferation, colony formation, invasion, and epithelial to mesenchymal transition, whereas depletion of miR-141-3p suppressed cervical cancer cell proliferation and invasion. FOXA2 was identified to be a target of miR-141-3p. Overexpression of miR-141-3p led to a marked inhibition of endogenous FOXA2 in cervical cancer cells. FOXA2 silencing phenocopied the effects of miR-141-3p overexpression on cervical cancer cell proliferation and invasion. Enforced expression of FOXA2 blocked the effects of miR-141-3p on cervical cancer cell proliferation and invasion. miR-141-3p overexpression significantly accelerated the growth of xenograft tumors, which was accompanied by a striking reduction in FOXA2 expression. miR-141-3p acts as an oncogene in cervical cancer largely through repression of FOXA2. Targeting miR-141-3p may represent a potential therapeutic strategy for cervical cancer.

Down-regulation of LHPP in cervical cancer influences cell proliferation, metastasis and apoptosis by modulating AKT

Cervical cancer is a leading severe malignancy throughout the world. Though various pathologies associated with cervical cancer progression have been demonstrated, further study is still necessary to reveal the tumorigenesis of cervical cancer. The protein histidine phosphatase LHPP is reported as a tumor suppressor. Histidine phosphorylation, also known as hidden phosphoproteome, is a poorly characterized post-translational modification of proteins. LHPP is evolutionarily conserved from worm to human. In the present study, we discovered that LHPP expression levels were lower in human cervical cancer tumors than that in adjacent normal tissue samples. LHPP expression levels were also reduced in several cervical cancer cell lines. Further, LHPP over-expression reduced the cell proliferation, migration and invasion, associated with the change of p53 and metastasis signaling pathways. Moreover, over-expressing LHPP markedly induced apoptosis in human cervical cancer cells via promoting the cleaved Caspse-3 and PARP. Importantly, we found that LHPP over-expression blocked AKT activation. Elevating AKT activity could abolish the role of LHPP over-expression in reducing cell proliferation and metastasis, as well as in inducing apoptotic response. Moreover, suppressing p53 expression with its inhibitor of PFTα abrogated the activity of LHPP to impede cell proliferation and metastasis, and to trigger apoptosis. AKT phosphorylation also restrained p53 expression levels in cervical cancer cells. In vivo, the anti-cervical cancer effects of LJPP were verified, which were also via the repression of cell proliferation and metastasis, and the induction of apoptosis. Therefore, LHPP could be considered as an effective candidate to develop effective therapeutic strategy against cervical cancer development.

Ultrasonic histogram assessment of early response to concurrent chemo-radiotherapy in patients with locally advanced cervical cancer: a feasibility study

PURPOSE

To monitor early response for locally advanced cervical cancers undergoing concurrent chemo-radiotherapy (CCRT) by ultrasonic histogram.

METHODS

B-mode ultrasound examinations were performed at 4 time points in thirty-four patients during CCRT. Six ultrasonic histogram parameters were used to assess the echogenicity, homogeneity and heterogeneity of tumors.

RESULTS

I_peak increased rapidly since the first week after therapy initiation, whereas W_low, W_high and A_high changed significantly at the second week. The average ultrasonic histogram progressively moved toward the right and converted into more symmetrical shape.

CONCLUSION

Ultrasonic histogram could be served as a potential marker to monitor early response during CCRT.

Intravoxel incoherent motion MRI as a means to measure in vivo perfusion: A review of the evidence

The idea that in vivo intravoxel incoherent motion magnetic resonance signal is influenced by blood motion in the microvasculature is exciting, because it suggests that local and quantitative perfusion information can be obtained in a simple and elegant way from a few diffusion-weighted images, without contrast injection. When the method was proposed in the late 1980s some doubts appeared as to its feasibility, and, probably because the signal to noise and image quality at the time was not sufficient, no obvious experimental evidence could be produced to alleviate them. Helped by the tremendous improvements seen in the last three decades in MR hardware, pulse design, and post-processing capabilities, an increasing number of encouraging reports on the value of intravoxel incoherent motion perfusion imaging have emerged. The aim of this article is to review the current published evidence on the feasibility of in vivo perfusion imaging with intravoxel incoherent motion MRI.

Cancer Metabolism and Tumor Heterogeneity: Imaging Perspectives Using MR Imaging and Spectroscopy

Cancer cells reprogram their metabolism to maintain viability via genetic mutations and epigenetic alterations, expressing overall dynamic heterogeneity. The complex relaxation mechanisms of nuclear spins provide unique and convertible tissue contrasts, making magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS) pertinent imaging tools in both clinics and research. In this review, we summarized MR methods that visualize tumor characteristics and its metabolic phenotypes on an anatomical, microvascular, microstructural, microenvironmental, and metabolomics scale. The review will progress from the utilities of basic spin-relaxation contrasts in cancer imaging to more advanced imaging methods that measure tumor-distinctive parameters such as perfusion, water diffusion, magnetic susceptibility, oxygenation, acidosis, redox state, and cell death. Analytical methods to assess tumor heterogeneity are also reviewed in brief. Although the clinical utility of tumor heterogeneity from imaging is debatable, the quantification of tumor heterogeneity using functional and metabolic MR images with development of robust analytical methods and improved MR methods may offer more critical roles of tumor heterogeneity data in clinics. MRI/MRS can also provide insightful information on pharmacometabolomics, biomarker discovery, disease diagnosis and prognosis, and treatment response. With these future directions in mind, we anticipate the widespread utilization of these MR-based techniques in studying in vivo cancer biology to better address significant clinical needs.

The value of advanced MRI techniques in the assessment of cervical cancer: a review

OBJECTIVES

To assess the value of new magnetic resonance imaging (MRI) techniques in cervical cancer.

METHODS

We searched PubMed and MEDLINE and reviewed articles published from 1990 to 2016 to identify studies that used MRI techniques, such as diffusion weighted imaging (DWI), intravoxel incoherent motion (IVIM) and dynamic contrast enhancement (DCE) MRI, to assess parametric invasion, to detect lymph node metastases, tumour subtype and grading, and to detect and predict tumour recurrence.

RESULTS

Seventy-nine studies were included. The additional use of DWI improved the accuracy and sensitivity of the evaluation of parametrial extension. Most studies reported improved detection of nodal metastases. Functional MRI techniques have the potential to assess tumour subtypes and tumour grade differentiation, and they showed additional value in detecting and predicting treatment response. Limitations included a lack of technical standardisation, which limits reproducibility.

CONCLUSIONS

New advanced MRI techniques allow improved analysis of tumour biology and the tumour microenvironment. They can improve TNM staging and show promise for tumour classification and for assessing the risk of tumour recurrence. They may be helpful for developing optimised and personalised therapy for patients with cervical cancer.

TEACHING POINTS

• Conventional MRI plays a key role in the evaluation of cervical cancer. • DWI improves tumour delineation and detection of nodal metastases in cervical cancer. • Advanced MRI techniques show promise regarding histological grading and subtype differentiation. • Tumour ADC is a potential biomarker for response to treatment.

Predictive and prognostic value of intravoxel incoherent motion (IVIM) MR imaging in patients with advanced cervical cancers undergoing concurrent chemo-radiotherapy

By using the intravoxel incoherent motion (IVIM) model, the diffusion-related coefficient (D) and the perfusion-related parameter (f) can be obtained simultaneously. Here, we explored the application of IVIM MR imaging in predicting long-term prognosis in patients with advanced cervical cancers treated with concurrent chemo-radiotherapy (CCRT). In this study, pelvic MR examinations including an IVIM sequence were performed on 30 women with advanced cervical cancers at three time points (within 2 weeks before, as well as 2 and 4 weeks after, the initiation of CCRT). The performance of tumour size and IVIM-derived parameters in predicting long-term prognosis was evaluated. After a median follow-up of 24 months (range, 10∼34 months), 25/30 (83.33%) patients were alive, and 21/30 (70.00%) remained free of disease. A shrinkage rate of maximum diameter (time point 1 vs. 3) ≥ 58.31% was useful in predicting a good long-term prognosis. The IVIM-derived apparent diffusion coefficient (ADC_IVIM) value at time point 2 and the ADC_IVIM and f values at time point 3 also performed well in predicting a good prognosis, with AUC of 0.767, 0.857 and 0.820, respectively. IVIM MR imaging has great potential in predicting long-term prognosis in patients with advanced cervical cancers treated with CCRT.

Three-dimensional power Doppler ultrasound in the early assessment of response to concurrent chemo-radiotherapy for advanced cervical cancer

Background Three-dimensional power Doppler ultrasound (3D-PDU) imaging has been widely applied to the differentiation of benign and malignant cervical lesions; however, its potential value for predicting response to chemo-radiotherapy has not been fully explored. Purpose To investigate the feasibility of 3D-PDU imaging in predicting treatment response in patients receiving concurrent chemo-radiotherapy (CCRT) for advanced cervical cancer. Material and Methods Fifty-two patients with advanced cervical cancer who received CCRT underwent 3D-PDU examinations at four timepoints: pre-therapy (baseline), 1 week and 2 weeks during, as well as immediately post CCRT. Final tumor response was determined by change in tumor size using magnetic resonance imaging (MRI). Cervical tumor volumes and vascular indices were calculated and compared with the clinical outcome. Results Of the 52 patients, 32 patients who completed all four examinations were included in the analyses: 21 were classified as complete response (CR) and 11 as partial response (PR). During the treatment, the CR group showed that 3D vascular indices (VI and VFI) significantly increased at 1 week ( P = 0.028, P = 0.017, respectively) then decreased at 2 weeks and obviously decreased at therapy completion (both P < 0.001), whereas tumors significantly decreased in volume at 2 weeks after therapy initiation ( P < 0.05). However, no significant differences in 3D vascular indices values were seen in the PR group during the treatment course (all P > 0.05). Conclusion Prospective longitudinal 3D-PDU imaging may have potentials in monitoring early therapeutic response to CCRT in patients with cervical cancer.

Hypoxia in cervical cancer: from biology to imaging

PURPOSE

Hypoxia imaging may improve identification of cervical cancer patients at risk of treatment failure and be utilized in treatment planning and monitoring, but its clinical potential is far from fully realized. Here, we briefly describe the biology of hypoxia in cervix tumors of relevance for imaging, and evaluate positron emission tomography (PET) and magnetic resonance imaging (MRI) techniques that have shown promise for assessing hypoxia in a clinical setting. We further discuss emerging imaging approaches, and how imaging can play a role in future treatment strategies to target hypoxia.

METHODS

We performed a PubMed literature search, using keywords related to imaging and hypoxia in cervical cancer, with a particular emphasis on studies correlating imaging with other hypoxia measures and treatment outcome.

RESULTS

Only a few and rather small studies have utilized PET with tracers specific for hypoxia, and no firm conclusions regarding preferred tracer or clinical potential can be drawn so far. Most studies address indirect hypoxia imaging with dynamic contrast-enhanced techniques. Strong evidences for a role of these techniques in hypoxia imaging have been presented. Pre-treatment images have shown significant association to outcome in several studies, and images acquired during fractionated radiotherapy may further improve risk stratification. Multiparametric MRI and multimodality PET/MRI enable combined imaging of factors of relevance for tumor hypoxia and warrant further investigation.

CONCLUSIONS

Several imaging approaches have shown promise for hypoxia imaging in cervical cancer. Evaluation in large clinical trials is required to decide upon the optimal modality and approach.

Early evaluation of irradiated parotid glands with intravoxel incoherent motion MR imaging: correlation with dynamic contrast-enhanced MR imaging

Background

Radiation-induced parotid damage is one of the most common complications in patients with nasopharyngeal carcinoma (NPC) undergoing radiotherapy (RT). Intravoxel incoherent motion (IVIM) magnetic resonance (MR) imaging has been reported for evaluating irradiated parotid damage. However, the changes of IVIM perfusion-related parameters in irradiated parotid glands have not been confirmed by conventional perfusion measurements obtained from dynamic contrast-enhanced (DCE) MR imaging. The purposes of this study were to monitor radiation-induced parotid damage using IVIM and DCE MR imaging and to investigate the correlations between changes of these MR parameters.

Methods

Eighteen NPC patients underwent bilateral parotid T1-weighted, IVIM and DCE MR imaging pre-RT (2 weeks before RT) and post-RT (4 weeks after RT). Parotid volume; IVIM MR parameters, including apparent diffusion coefficient (ADC), pure diffusion coefficient (D), pseudo-diffusion coefficient (D*), and perfusion fraction (f); and DCE MR parameters, including maximum relative enhancement (MRE), time to peak (TTP), Wash in Rate, and the degree of xerostomia were recorded. Correlations of parotid MR parameters with mean radiation dose, atrophy rate and xerostomia degree, as well as the relationships between IVIM and DCE MR parameters, were investigated.

Results

From pre-RT to post-RT, all of the IVIM and DCE MR parameters increased significantly (p < 0.001 for ADC, D, f, MRE, Wash in Rate; p = 0.024 for D*; p = 0.037 for TTP). Change rates of ADC, f and MRE were negatively correlated with atrophy rate significantly (all p < 0.05). Significant correlations were observed between the change rates of D* and MRE (r = 0.371, p = 0.026) and between the change rates of D* and TTP (r = 0.396, p = 0.017). The intra- and interobserver reproducibility of IVIM and DCE MR parameters was good to excellent (intraclass correlation coefficient, 0.633–0.983).

Conclusions

Early radiation-induced changes of parotid glands could be evaluated by IVIM and DCE MR imaging. Certain IVIM and DCE MR parameters were correlated significantly.