Dynamic contrast-enhanced MR imaging of uterine cervical cancer: pharmacokinetic analysis with histopathologic correlation and its importance in predicting the outcome of radiation therapy

Useful MRI Findings for Minimally Invasive Surgery for Early Cervical Cancer

Simple Summary

Radical hysterectomy and lymph node dissection are extensive procedures with severe post-operative morbidities and should be avoided on patients with low risk of recurrence. Still, due to lack of good prognostic tools, radical surgery is performed on most patients with early stage cervical cancer, leading to overtreatment and unnecessary morbidities. The recent International Federation of Gynecology and Obstetrics (FIGO) staging system accepts the use of magnetic resonance imaging (MRI) in addition to physical examination. Currently, 3 Tesla (3T) MRI is available widely and, due to its high soft tissue contrast, can provide more useful information on precise estimation of tumor size and metastasis than can physical examination in patients with cervical cancer. Therefore, this imaging modality can help gynecologic oncologists to determine whether minimally invasive surgery is necessary and can be used for early detection of small recurrent cancers.

Abstract

According to the recent International Federation of Gynecology and Obstetrics (FIGO) staging system, Stage III cervical cancer indicates pelvic or paraaortic lymph node metastasis. Accordingly, the new FIGO stage accepts imaging modalities, such as MRI, as part of the FIGO 2018 updated staging. Magnetic resonance imaging (MRI) is the best imaging modality to estimate the size or volume of uterine cancer because of its excellent soft tissue contrast. As a result, MRI is being used increasingly to determine treatment options and follow-up for cervical cancer patients. Increasing availability of cancer screening and vaccination have improved early detection of cervical cancer. However, the incidence of early cervical cancers has increased compared to that of advanced cervical cancer. A few studies have investigated if MRI findings are useful in management of early cervical cancer. MRI can precisely predict tumor burden, allowing conization, trachelectomy, and simple hysterectomy to be considered as minimally invasive treatment options for early cervical cancer. This imaging modality also can be used to determine whether there is recurrent cancer following minimally invasive treatments. The purpose of this review is to highlight useful MRI features for managing women with early cervical cancer.

Volume computed tomography perfusion as a predictive marker for treatment response to concurrent chemoradiotherapy in cervical cancer: a prospective study

BACKGROUND

Computed tomography perfusion (CTP) can provide information on blood perfusion as a reliable marker of tumor response to therapy.

PURPOSE

To assess the role of volume CTP (vCTP) parameters in predicting treatment response to concurrent chemoradiotherapy (CCRT) for cervical cancer.

MATERIAL AND METHODS

Thirty-three patients with cervical cancer underwent vCTP. Three CTP parameters of cervical cancer-including arterial flow (AF), blood volume (BV), and permeability surface (PS)-were measured in two different ways: the region of interest incorporating the "local hot" with the highest enhancement and "cold spot" with the lowest enhancement; and "whole-tumor" measurements. The patients were divided into non-residual and residual tumor groups according to the short-term response to treatment. The clinical and perfusion parameters were compared between the two groups.

RESULTS

There was no significant difference in age, body mass index, FIGO stage, pathological grade, or pretreatment tumor size between the two groups (P > 0.05). The non-residual tumor group had higher pretreatment AF in high-perfusion and low-perfusion subregions than the residual tumor group (P <0.05), but the AF in whole-tumor regions was not different between the two groups (P > 0.05). There were no differences in BV and PS between the two groups (P > 0.05). The diagnostic potency of AF in the low-perfusion subregion was higher than that in the high-perfusion subregion.

CONCLUSION

vCTP parameters are valuable for the prediction of short-term effects. The AF in the low-perfusion subregion was a more effective index for predicting treatment response to CCRT of cervical cancer.

DCE-MRI Quantitative Parameters as Predictors of Treatment Response in Patients With Locally Advanced Cervical Squamous Cell Carcinoma Underwent CCRT

Purpose

To evaluate the predictive value of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) quantitative parameters in treatment response to concurrent chemoradiotherapy (CCRT) for locally advanced cervical squamous cell carcinoma (LACSC).

Methods and materials

LACSC patients underwent CCRT had DCE-MRI before (e0) and after 3 days of treatment (e3). Extended Tofts Linear model with a user arterial input function was adopted to generate quantitative measurements. Endothelial transfer constant (K^trans), reflux rate (K_ep), fractional extravascular extracellular space volume (V_e), and fractional plasma volume (V_p) were calculated, and percentage changes ΔK^trans, ΔK_ep, ΔV_e, and ΔV_p were computed. The correlations of these measurements with the tumor regression rate were analyzed. The predictive value of these parameters on treatment outcome was generated by the receiver operating characteristic (ROC) curve. Univariate and multivariate logistic regression analyses were conducted to find the independent variables.

Results

K^trans-e0, K_ep -e0, ΔK^trans, and ΔV_e were positively correlated with the tumor regression rate. Mean values of K^trans-e0, K^trans-e3, ΔK^trans, and ΔV_e were higher in the non-residual tumor group than residual tumor group and were independent prognostic factors for predicting residual tumor occurrence. K^trans-e3 showed the highest area under the curve (AUC) for treatment response prediction.

Conclusions

Quantitative parameters at e0 and e3 from DCE-MRI could be used as potential indicators for predicting treatment response of LACSC.

Perfusion parameters of intravoxel incoherent motion based on tumor edge region of interest in cervical cancer: evaluation of differentiation and correlation with dynamic contrast-enhanced MRI

BACKGROUND

Intravoxel incoherent motion (IVIM) diffusion-weighted imaging (DWI) is a functional magnetic resonance imaging (MRI) sequence.

PURPOSE

To evaluate the value of perfusion parameters derived from IVIM-DWI based on tumor edge region of interest (ROI) in differentiation in cervical cancer and investigate the relationship between IVIM and dynamic contrast-enhanced MRI (DCE-MRI).

MATERIAL AND METHODS

Thirty-three patients with pathologically diagnosed squamous cell carcinoma who underwent IVIM-DWI (nine b-values: 1-1000 s/mm²) and DCE-MRI were retrospectively assessed in this study. Parameters of IVIM (D, f, D*, fD*) and quantitative parameters of DCE-MRI (Ktrans, Kep, Ve) were derived using tumor edge ROI. Mann-Whitney U test was used to compare parameters between pathological grades and receiver operating characteristic (ROC) curves were used. Pearson's correlation coefficient (r) evaluated the correlation between perfusion parameters derived from IVIM and DCE-MRI.

RESULTS

The poorly differentiated group showed the significantly lower D value and the higher f, Ktrans and Kep values than the well-to-moderately differentiated group (P < 0.05). ROC curves indicated that f < 26%, Ktrans <0.38/min, and Kep <1.62/min could differentiate the poorly differentiated group from the well-to-moderately differentiated group (AUC 0.753-0.808). Significantly positive correlations were found between f and Ktrans (r = 0.422, P = 0.014) and between fD* and Ktrans (r = 0.448, P = 0.009).

CONCLUSION

Perfusion parameters derived from IVIM based on tumor edge ROI may offer additional value in differentiation in cervical cancer, and the IVIM perfusion parameters showed moderate positive correlations with quantitative perfusion parameters from DCE-MRI, while f and fD* showed promising significance.

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).

Differentiation of endometrial adenocarcinoma from adenocarcinoma of cervix using kinetic parameters derived from DCE-MRI

PURPOSE

This prospective study aimed to investigate the value of kinetic parameters derived from dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) in differentiating uterine endometrioid adenocarcinoma (EAC) from adenocarcinoma of cervix (AdC).

METHODS

Seventy-five newly diagnosed patients with distinctive pathology underwent DCE-MRI. Observers independently calculated the tumor diameters and DCE-MRI parameters using both population and individual-based arterial input function (AIF). Inter-observer consistency was evaluated, and a comparative analysis between EAC (n = 47) and AdC (n = 28) was performed. Regression analysis was used to select parameters that best distinguished EAC from AdC, and to generate predictive models. Receiver operating characteristic curve (ROC) was applied to calculate the diagnostic efficiency of single parameter and the predictive models.

RESULTS

Inter-observer consistency was excellent (intra-class correlation [ICC] = 0.902-0.981), especially when calculated via population AIF with relatively higher ICC and smaller SD on Bland-Altman plot. Tumor diameters were not correlated with tumor types. All the DCE-MRI parameters were lower in EAC compared to AdC, except K_ep by population AIF and TTP by both sets of AIFs. The statistical parameters were V_e, Maxslop, and Maxconc by population AIF, and Maxslop and K^trans by individual AIF included in the predictive models, respectively. The two predictive models with combined parameters showed improved diagnostic efficiency in differentiating these two diseases compared with a single parameter.

CONCLUSION

DCE-MRI can quantitatively evaluate the perfusion difference between EAC and AdC, thus improving the identification of uterine adenocarcinoma with uncertain biopsy pathology.

Intravoxel incoherent motion diffusion-weighted imaging evaluated the response to concurrent chemoradiotherapy in patients with cervical cancer

To evaluate the application of multiple b values diffusion-weighted imaging based on biexponential signal decay model to predict the response to concurrent chemoradiotherapy in cervical cancer patients.This prospective study enrolled 28 patients (mean age: 50.89 ± 10.70 years) with cervical cancer confirmed by biopsy who received concurrent chemoradiotherapy. Pelvic magnetic resonance scans were performed 2 weeks before, 7 days and 21 days after the initiation of therapy, and 1 month after the end of the treatment. Diffusion-weighted imaging with b values of 0, 50, 450, and 850 s/mm were performed, and tumor volume, means of tumor apparent diffusion coefficient (ADC)min, ADCmean, ADCslow, ADCfast, and Ffast were measured.Pretreatment ADCmin and ADCslow of good outcome group were significantly higher than those of poor outcome group (P < .05). At the 7th day of the treatment, Ffast and its change rate of good outcome group were significantly higher than those of poor outcome group (P < .05). At the 7th day and 21st day of the treatment, Ffast showed a slowly increasing tendency with no significant difference compared with pretreatment value in poor outcome group (P < .05). One month post-treatment, only ADCslow change rate was significantly higher in good outcome group than that in poor outcome group.Intravoxel incoherent motion-related ADC values could be utilized to better predict the outcome of cervical cancer chemoradiotherapy.

Imaging Features of the Whole Uterus Volume CT Perfusion and Influence Factors of Blood Supply: A Primary Study in Patients with Cervical Squamous Carcinoma

RATIONALE AND OBJECTIVES

To explore the imaging features of whole uterus volume CT perfusion (vCTP) and the influence factors of blood supply in cervical squamous carcinoma (CSC).

MATERIALS AND METHODS

vCTP was performed on a 640-slice computed tomography system in 43 patients with CSC diagnosed by biopsy, and 24 cases of them underwent magnetic resonance imaging. The size of the tumor was measured on vCTP and magnetic resonance (MR) images. Perfusion parameters, including arterial blood flow (AF), blood volume, and permeability surface (PS), were measured by two radiologists, using interclass correlation coefficient to evaluate the interobserver reliability. The difference of tumor size and perfusion data was analyzed by paired t test and rank sum test. The correlation of perfusion parameters with some factors was analyzed by Pearson or Spearman correlation analysis.

RESULTS

Tumor sizes were not significantly different between vCTP and MR images. The interclass correlation coefficient of each parameter was 0.818-0.945. The AF value of CSC was significantly higher than normal uterine body, and the blood volume and PS values of CSC were not statistically different compared with those of normal uterine body. There was no significant difference in AF value of CSC among different FIGO stages and pathological grades. The AF and PS values of CSC were negatively correlated with the age of the patients.

CONCLUSION

The vCTP could accurately shows the size of the CSC with use of MR as the reference standard, and its perfusion parameters have good measurement stability; the CSC was hypervascular, but this trend was less pronounced in older women.

Pharmacokinetic analysis of DCE-MRI data of locally advanced cervical carcinoma with the Brix model

Background: There is significant evidence that DCE-MRI may have the potential to provide clinically useful biomarkers of the outcome of locally advanced cervical carcinoma. However, there is no consensus on how to analyze DCE-MRI data to arrive at the most powerful biomarkers. The purpose of this study was to analyze DCE-MRI data of cervical cancer patients by using the Brix pharmacokinetic model and to compare the biomarkers derived from the Brix analysis with biomarkers determined by non-model-based analysis [i.e., low-enhancing tumor volume (LETV) and tumor volume with increasing signal (TVIS)] of the same patient cohort. Material and methods: DCE-MRI recordings of 80 patients (FIGO stage IB-IVA) treated with concurrent cisplatin-based chemoradiotherapy were analyzed voxel-by-voxel, and frequency distributions of the three parameters of the Brix model (A_Brix, k_ep, and k_el) were determined. Moreover, risk volumes were calculated from the Brix parameters and termed RV-A_Brix, RV-k_ep, and RV-k_el, where the RVs represent the tumor volume with voxel values below a threshold value determined by ROC analysis. Disease-free survival (DFS) and overall survival (OS) were used as measures of treatment outcome. Results: Significant associations between the median value or any other percentile value of A_Brix, k_ep, or k_el and treatment outcome were not found. However, RV-A_Brix, RV-k_ep, and RV-k_el correlated with DFS and OS. Multivariate analysis revealed that the prognostic power of RV-A_Brix, RV-k_ep, and RV-k_el was independent of well-established clinical prognostic factors. RV-A_Brix, RV-k_ep, and RV-k_el correlated with each other as well as with LETV and TVIS. Conclusion: Strong biomarkers of the outcome of locally advanced cervical carcinoma can be provided by subjecting DCE-MRI series to pharmacokinetic analysis using the Brix model. The prognostic power of these biomarkers is not necessarily superior to that of biomarkers identified by non-model-based analyses.

Hypoenhancing prostate cancers on dynamic contrast-enhanced MRI are associated with poor outcomes in high-risk patients: results of a hypothesis generating study

PURPOSE

To investigate the association of hypoenhancement on dynamic Contrast enhanced (DCE) with prostate cancer patient outcomes.

MATERIAL AND METHODS

This was a single-institution retrospective Institutional Review Board (IRB)-approved cohort study of 54 men who had prostate Magnetic Resonance Imaging (MRI) within 6 months of cancer diagnosis between 01/2012 to 03/2014. Two readers independently identified the dominant MRI-lesions utilizing Prostate Imaging-Reporting and Data System-version2- guidelines. These lesions were classified as hypoenhancing or hyperenhancing, compared to normal peripheral zone using quantitative DCE analysis. The t test for unequal sample sizes and the two-sample Wilcoxon rank-sum tests were used to compare groups. Logistic regression determined if DCE characteristics predict the development of metastases or prostate cancer death.

RESULTS

Time-to-progression was significantly shorter for hypoenhancing tumors (6.2 vs. 24.8 months, p = 0.05). Men with these lesions had a higher odds of having poor outcome (univariate logistic regression, odds ratio (OR) 6.79, 95% confidence interval (CI) 1.45-31.72, p = 0.02; multivariate analysis, OR 2.05, 95% CI 0.30-13.72, p = 0.47). Hypoenhancing tumors were larger (33.1 vs. 19.1 mm, p < 0.001) and more likely to be intermediate (Gleason scores 3 + 4 and 4 + 3) and high-grade (Gleason scores ≥ 4 + 4) prostate cancers (p = 0.05). Men in the hypoenhancing group had a higher mean prostate-specific antigen (PSA) value (87.6 vs. 24.8 ng/dL, p = 0.01) and PSA density (1.54 vs. 0.72, p = 0.03). The mean K_trans and k_ep of hypoenhancing lesion were lower when compared to hyperenhancing lesions (p = 0.03 and p = 0.04). V_e values did not differ (p = 0.25).

CONCLUSION

Men with hypoenhancing prostate cancers may have a worse prognosis than men with hyperenhancing tumors.

Response to neoadjuvant chemoradiotherapy for locally advanced rectum cancer: Texture analysis of dynamic contrast-enhanced MRI

BACKGROUND

Tumor heterogeneity can be assessed by texture analysis (TA). TA has been applied using diffusion-weighted imaging and apparent diffusion coefficient maps to predict pathological responses to preoperative chemoradiation therapy (CRT) in patients with locally advanced rectal cancer (LARC).

PURPOSE

To evaluate the texture parameters obtained from K ^trans maps derived from dynamic contrast-enhanced (DCE)-MRI for predicting pathological responses to preoperative CRT for LARCs.

STUDY TYPE

Retrospective.

POPULATION

Altogether, 83 patients (26 women, 57 men) with rectal cancer met the inclusion criteria.

FIELD STRENGTH/SEQUENCE

3.0T/T₁ -weighted DCE-MRI sequence.

ASSESSMENT

After CRT, each tumor was assessed by a pathologist who assigned a tumor regression grade (TRG), thereby identifying pathologically complete responders (pCR; TRG 1) and good responders (GR; TRG1 + TRG2). TA was then applied to the DCE-MRI K ^trans maps. The K ^trans value, several TA parameters, and tumor volumes were calculated.

STATISTICAL TESTS

The Shapiro-Wilk test was used to verify that the data had normal distribution. Results of parameters measured before and after CRT were compared using paired-sample t-tests. Value changes of each parameter in the combined pCR/GR group were compared using independent sample t-tests. Receiver operating characteristic curves and areas under the curve (AUC) were calculated to assess the diagnostic performance of each parameter related to CRT effectiveness.

RESULTS

There were 15 pCR (16.9%) and 21 GR (25.3%) patients. Tumor volume, mean K ^trans , entropy, and correlation decreased and energy values increased significantly in these groups compared with those of the non-PCR and non-GR groups. ΔCorrelation (Δcorrelation = postcorrelation - precorrelation) was found to be a valuable parameter for identifying pCR/GR patients (AUC 0.895, sensitivity 86.7%, specificity 81.8%).

DATA CONCLUSION

TA parameters from the DCE-MRI K ^trans map can predict the efficacy of CRT for treating LARCs. Also, Δcorrelation may be useful for identifying patients who will be responsive to CRT.

LEVEL OF EVIDENCE

4 Technical Efficacy: Stage 3 J. Magn. Reson. Imaging 2019;49:885-893.

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.

Pretreatment late-phase DCE-MRI predicts outcome in locally advanced cervix cancer

BACKGROUND

Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) may provide prognostic biomarkers for cervix carcinoma. We have shown previously that the early phase of the signal intensity-versus-time curve (SITC) may have significant prognostic power. The purpose of the present investigation was to explore the prognostic value of the late phase of the SITC.

MATERIAL AND METHODS

DCE-MRI data of 80 patients (FIGO stage IB-IVA) treated with concurrent chemoradiotherapy were examined. Four parameters were calculated from the late-phase SITC: tumor volume with decreasing signal, tumor fraction with decreasing signal, tumor volume with increasing signal (TVIS), and tumor fraction with increasing signal.

RESULTS

Multivariate analysis involving clinical parameters and late-phase SITC parameters suggested that TVIS is a strong independent prognostic factor for both disease-free and overall survival. When early-phase SITC parameters were included in the multivariate analysis, the early-phase SITC, but not the late-phase SITC, was found to have independent prognostic value.

CONCLUSION

The late-phase SITC can provide prognostic factors for the outcome of cervix carcinoma, that is, a large tumor volume with increasing late-phase SITCs is associated with poor outcome. However, the prognostic power of the late-phase SITC is not as strong as that of the early-phase SITC.

Functional MR imaging in gynecologic malignancies: current status and future perspectives

Using functional MR imaging techniques, we can approach the functional assessment of gynecologic malignancies. Among them, diffusion-weighted imaging (DWI) and dynamic contrast-enhanced MR imaging (DCE-MRI) are two important techniques. This article provides an overview of functional MR imaging techniques, focusing DWI and DCE-MRI on clinical application in gynecologic malignancies. Functional MR imaging techniques play an important role in detection, characterization, staging, treatment response, and outcome prediction, as well as providing conventional morphologic imaging. Familiarity with the characteristics and imaging features of functional MR imaging in gynecologic malignancies will facilitate prompt and accurate diagnosis and treatment.

Intravoxel incoherent motion diffusion weighted MRI of cervical cancer - Correlated with tumor differentiation and perfusion

OBJECTIVES

To investigate the value of parameters derived from IVIM model in grading of uterine cervical cancer and the relationship between perfusion parameters derived from IVIM and that from DCE-MRI.

METHODS

Parameters of DWI (ADC, D, f, D*) and semi-quantitative parameters of DCE-MRI (Slop, Maxslop, CER, Washout, AUC90) were assessed in 24 female with cervical cancers. Except for ROIs encompassed all of the area of tumors in axial plane (A_all), ROIs on tumor edge (A_peri) and tumor center (A_central) were drawn. All of the parameters were compared among three pathology grades. Perfusion parameters derived from IVIM were correlated with that from DCE-MRI.

RESULTS

For G1, G2 and G3 tumors, on tumor edge ADC=(1.03±0.11), (1.05±0.10), (0.90±0.05)×10(-3)mm(2)/s, D=(0.80±0.11), (0.78±0.07), (0.69±0.06)×10(-3)mm(2)/s, and f=(0.19±0.03), (0.22±0.02), (0.24±0.03). The differences among groups were significant (P<0.05). On tumor center, ADC=(0.90±0.10), (0.85±0.03), (0.80±0.07)×10(-3)mm(2)/s with significant differences (P=0.027). The other parameter, D and f of tumor center, as well as D* of all tumor areas, were of no statistic significance. Most of the DCE-MRI parameters negatively correlated with tumor volume. Although the correlation between f and slop was statistic significant, R=0.277 meant a negligible correlation. f had week correlation with Maxslop, CER and AUC90 (R=0.361, 0.400 and 0.405; P<0.001). D* showed no statistic significant correlation with all of the DCE parameters.

CONCLUSION

IVIM model could possibly be used to evaluate tumor differentiation and perfusion, providing an alternative for DCE-MRI.

Tumor Vascular Permeability Pattern Is Associated With Complete Response in Immunocompetent Patients With Newly Diagnosed Primary Central Nervous System Lymphoma: Retrospective Cohort Study

A dynamic contrast-enhanced MR imaging (DCE-MRI) could provide the information about tumor drug delivery efficacy. We investigated the potential utility of the permeability pattern of DCE-MRI for predicting tumor response to high dose-methotrexate treatment and progression-free survival (PFS) in patients with primary CNS lymphoma (PCNSL). Clinical and conventional imaging parameters were assessed as potential predictors of tumor response in 48 immunocompetent PCNSL patients in a preliminary study. Fifty additional immunocompetent patients (27 men and 23 women; mean age, 60.6 years) with PCNSL underwent DCE-MRI before starting first-line treatment with high dose-methotrexate. The DCE-MRI pattern was categorized as diffuse or nondiffuse. After 4 courses of high dose methotrexate, patients underwent follow-up brain MR imaging to identify their complete response (CR). Predictors of CR and PFS were analyzed using clinical parameters, conventional MRI, and DCE-MRI. CR was noted in 20 (74.1%) of 27 patients with diffuse DCE-MRI pattern and in 4 (17.4%) of 23 patients with nondiffuse DCE-MRI pattern. The diffuse DCE-MRI pattern showed a significantly higher association with CR than the nondiffuse pattern (P < 0.001). Multivariate Cox proportional hazards model revealed that the DCE-MRI pattern (hazard ratio = 0.70; P = 0.045), age (hazard ratio = 1.47; P = 0.041), and adjuvant autologous stem-cell transplantation (hazard ratio = 6.97; P = 0.003) tended to be associated with a PFS. The pretreatment diffuse DCE-MRI pattern can be used as a potential imaging biomarker for predicting CR and a longer PFS in patients with newly diagnosed PCNSLs.

MRI of the stomach: a pictorial review with a focus on oncological applications and gastric motility

The purpose of this pictorial review is to demonstrate gastric pathology seen on magnetic resonance imaging (MRI) and discuss the essential MRI sequences for the evaluation of benign and malignant gastric pathologies. Common tumors of the stomach, polyposis syndromes, iatrogenic conditions, as well as other conditions of the stomach will be reviewed. The utility of MRI in the evaluation of patients with gastric malignancies and disorders of gastric motility will also be discussed.

Models and methods for analyzing DCE-MRI: a review

PURPOSE

To present a review of most commonly used techniques to analyze dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI), discusses their strengths and weaknesses, and outlines recent clinical applications of findings from these approaches.

METHODS

DCE-MRI allows for noninvasive quantitative analysis of contrast agent (CA) transient in soft tissues. Thus, it is an important and well-established tool to reveal microvasculature and perfusion in various clinical applications. In the last three decades, a host of nonparametric and parametric models and methods have been developed in order to quantify the CA's perfusion into tissue and estimate perfusion-related parameters (indexes) from signal- or concentration-time curves. These indexes are widely used in various clinical applications for the detection, characterization, and therapy monitoring of different diseases.

RESULTS

Promising theoretical findings and experimental results for the reviewed models and techniques in a variety of clinical applications suggest that DCE-MRI is a clinically relevant imaging modality, which can be used for early diagnosis of different diseases, such as breast and prostate cancer, renal rejection, and liver tumors.

CONCLUSIONS

Both nonparametric and parametric approaches for DCE-MRI analysis possess the ability to quantify tissue perfusion.

Short-term pretreatment DCE-MRI in prediction of outcome in locally advanced cervical cancer

BACKGROUND AND PURPOSE

Several investigators have indicated that dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) has the potential to provide biomarkers for personalized treatment of cervical carcinoma. However, some clinical studies have suggested that treatment failure is associated with low tumor signal enhancement, whereas others have reported associations between high signal enhancement and poor outcome. The purpose of this investigation was to clear up these conflicting reports and to provide a method for identifying biomarkers that easily can be implemented in routine DCE-MRI diagnostics.

METHODS

The study involved 85 patients (FIGO stage IB through IVA) treated with concurrent chemoradiotherapy. Low-enhancing tumor volume (LETV) and low-enhancing tumor fraction (LETF), defined as the volume and fractional volume of low-enhancing voxels, respectively, were calculated from signal intensities recorded within 1 min after contrast administration by using two methods reported to give conflicting conclusions.

RESULTS

Multivariate analysis involving tumor volume, lymph node status, FIGO stage, and LETV or LETF revealed that LETV and LETF provided independent prognostic information on treatment outcome, independent of the method of calculation.

CONCLUSION

Low signal enhancement is associated with poor prognosis in cervical carcinoma, and biomarkers predicting poor outcome can be provided by short-term DCE-MRI without advanced image analysis.

Diffusion-weighted imaging and dynamic contrast-enhanced MRI in assessing response and recurrent disease in gynaecological malignancies

Magnetic resonance imaging (MRI) has an established role in imaging pelvic gynaecological malignancies. It is routinely used in staging endometrial and cervical cancer, characterizing adnexal masses, selecting optimal treatment, monitoring treatment and detecting recurrent disease. MRI has also been shown to have an excellent performance and an evolving role in surveillance of patients after chemoradiotherapy in cervical cancer, post-trachelectomy, detecting early recurrence and planning exenterative surgery in isolated central recurrences in both cervical and endometrial cancer and in young patients on surveillance for medically managed endometrial cancer. However, conventional MRI still has limitations when the morphological appearance of early recurrent or residual disease overlaps with normal pelvic anatomy or treatment effects in the pelvis. In particular, after chemoradiotherapy for cervical cancer, distinguishing between radiotherapy changes and residual or early recurrent disease within the cervix or the vaginal vault can be challenging on conventional MRI alone. Therefore, there is an emerging need for functional imaging to overcome these limitations. The purpose of this paper is to discuss the emerging functional MRI techniques and their applications in predicting treatment response, detecting residual disease and early recurrent disease to optimize the treatment options available using diffusion-weighted imaging and dynamic contrast enhancement particularly in cervical and endometrial cancer.

Magnetic resonance imaging of the tumor microenvironment in radiotherapy: perfusion, hypoxia, and metabolism

The tumor microenvironment is characterized by hypoxia, low pH, and high interstitial fluid pressure. Hypoxic regions in tumors with low partial pressure of oxygen (pO2) levels can result in resistance to radiotherapy, thus causing local failure. Therefore, it would be desirable to noninvasively measure pO2 levels in the tumor before, during, and after treatment to better customize therapy and follow treatment response. Several techniques used in preclinical and clinical studies to obtain the pO2 status of tissue, such as dynamic contrast-enhanced magnetic resonance imaging, blood oxygen level-dependent imaging, and electron paramagnetic resonance imaging, are reviewed. Furthermore, the ability to hyperpolarize specific metabolic substrates that are isotopically labeled with (13)C coupled with magnetic resonance spectroscopy enables noninvasive imaging of tissue metabolism, such as glycolysis.

Magnetic resonance imaging using gadolinium-based contrast agents

The purpose of this article was to review the basic properties of available gadolinium-based magnetic resonance contrast agents, discuss their fundamental differences, and explore common and evolving applications of gadolinium-based magnetic resonance contrast throughout the body excluding the central nervous system. A more specific aim of this article was to explore novel uses of these gadolinium-based contrast agents and applications where a particular agent has been demonstrated to behave differently or be better suited for certain applications than the other contrast agents in this class.

Validation of optimal DCE-MRI perfusion threshold to classify at-risk tumor imaging voxels in heterogeneous cervical cancer for outcome prediction

PURPOSE

To classify tumor imaging voxels at-risk for treatment failure within the heterogeneous cervical cancer using DCE MRI and determine optimal voxel's DCE threshold values at different treatment time points for early prediction of treatment failure.

MATERIAL AND METHOD

DCE-MRI from 102 patients with stage IB2-IVB cervical cancer was obtained at 3 different treatment time points: before (MRI 1) and during treatment (MRI 2 at 2-2.5 weeks and MRI 3 at 4-5 weeks). For each tumor voxel, the plateau signal intensity (SI) was derived from its time-SI curve from the DCE MRI. The optimal SI thresholds to classify the at-risk tumor voxels was determined by the maximal area under the curve using ROC analysis when varies SI value from 1.0 to 3.0 and correlates with treatment outcome.

RESULTS

The optimal SI thresholds for MRI 1, 2 and 3 were 2.2, 2.2 and 2.1 for significant differentiation between local recurrence/control, respectively, and 1.8, 2.1 and 2.2 for death/survival, respectively.

CONCLUSION

Optimal SI thresholds are clinically validated to quantify at-risk tumor voxels which vary with time. A single universal threshold (SI=1.9) was identified for all 3 treatment time points and remained significant for the early prediction of treatment failure.

Basic T1 Perfusion Magnetic Resonance Imaging Evaluation of the Therapeutic Effect of Neoadjuvant Chemotherapy in Locally Advanced Cervical Cancer

Objective

The objective of this study was to evaluate the dynamic changes of blood perfusion coinciding with tumor regression after neoadjuvant chemotherapy (NACT) in locally advanced cervical cancer (LACC).

Methods

Thirty patients with LACC received conventional 3.0-T magnetic resonance imaging and perfusion-weighted imaging scans at 3 different times (before NACT, 2 weeks after the first NACT, and 2 weeks after the second NACT). Characteristics of time-intensity diagrams and patterns of blood perfusion maps according to the parameter of area under the curve (AUC) were observed. Eight perfusion parameters were compared among 3 time points at 2 different chemotherapy-sensitive groups by the software of Basic T1 Perfusion.

Results

The effective chemotherapy rate was 73.3% (22/30). The characteristic of time-intensity diagrams in cervical cancer was a rapid onset with plateau. There were 3 patterns of AUC perfusion maps. The common perfusion map was rich blood supply type in the effective chemotherapy group and peripheral blood supply type in the ineffective chemotherapy group. Four parameter values (relative enhancement, maximum enhancement, wash-in rate, and AUC) were significantly reduced 2 weeks after the second NACT than those before the therapy (P = 0.000; P = 0.009; P = 0.011; and P = 0.000) in the effective chemotherapy group, especially the value of relative enhancement 2 weeks after the first NACT, was obviously decreased compared to that before the therapy (P = 0.042). The value of time to peak 2 weeks after the second NACT was significantly longer than that before the therapy in the effective chemotherapy group (P = 0.001). There were no obvious changes of blood perfusion parameters among the 3 different times in the ineffective chemotherapy group.

Conclusions

Tumor blood perfusion has obviously decreased after effective NACT in the treatment of LACC.

Dynamic contrast-enhanced MR imaging predicts local control in oropharyngeal or hypopharyngeal squamous cell carcinoma treated with chemoradiotherapy

The role of pretreatment dynamic contrast-enhanced perfusion MR imaging (DCE-PWI) and diffusion-weighted MR imaging (DWI) in predicting the treatment response of oropharyngeal or hypopharyngeal squamous cell carcinoma (OHSCC) to chemoradiation remains unclear. We prospectively investigated the ability of pharmacokinetic parameters derived from pretreatment DCE-PWI and DWI to predict the local control of OHSCC patients treated with chemoradiation. Between August, 2010 and March, 2012, patients with untreated OHSCC scheduled for chemoradiation were eligible for this prospective study. DCE-PWI and DWI were performed in addition to conventional MRI. The relationship of local control with the following clinical and imaging variables was analyzed: the hemoglobin level, T-stage, tumor location, gross tumor volume, maximum standardized uptake value, metabolic tumor volume and total lesion glycolysis on FDG PET/CT, transfer constant (K^trans), volume of blood plasma and volume of extracellular extravascular space on DCE-PWI, and apparent diffusion coefficient on DWI of the primary tumor. The patients were also divided into a local control group and a local failure group, and their clinical and imaging parameters were compared. There were 58 patients (29 with oropharynx squamous cell carcinoma [SCC] and 29 with hypopharynx SCC) with successful pretreatment DCE-PWI and DWI available for analysis. After a median follow-up of 18.2 months, 17 (29.3%) participants had local failure, whereas the remaining 41 patients achieved local control. Univariate analysis revealed that only the K^trans value was significantly associated with local control (P = 0.03). When the local control and local failure groups were compared, significant differences were observed in K^trans and the tumor location (P = 0.01 and P = 0.04, respectively). In the multivariable analysis, only K^trans was statistically significant (P = 0.04). Our results suggest that pretreatment K^trans may help predict the local control in OHSCC patients treated with chemoradiation.

Diseases of the female pelvis: advances in imaging evaluation

Magnetic resonance (MR) imaging has been widely accepted as a powerful imaging modality for the evaluation of the pelvis because of its intrinsic superior soft tissue contrast compared with that of computed tomography. In certain cases, however, the morphologic study provided by MR imaging may not be enough. Functional evaluation with perfusion and diffusion, which allow estimation of the microvascular characteristics and cellularity of the lesions, favors the differentiation of benign from malignant lesions. This article focuses on new magnetic resonance techniques and their contribution to the differentiation and characterization of pelvic pathologies.

New MR techniques in gynecologic cancer

OBJECTIVE

Functional MR techniques report on a variety of biologic features of tumors: dynamic contrast-enhanced, diffusion-weighted, and intrinsic susceptibility-weighted MRI and MR spectroscopy reflect, at a simplistic level, vascularity, cellularity, hypoxic status, and metabolism, respectively. This article reviews the evidence for each of the functional MR readouts to determine these clinical end points and thus influence the management of ovarian, endometrial, and cervical cancer.

CONCLUSION

These techniques may be implemented in gynecologic malignancies to detect, characterize, and stage tumors as well as potentially to predict the outcome and measure response to treatment.

Pharmacokinetic parameters derived from dynamic contrast enhanced MRI of cervical cancers predict chemoradiotherapy outcome

PURPOSE

To assess the prognostic value of pharmacokinetic parameters derived from pre-chemoradiotherapy dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) of cervical cancer patients.

MATERIALS AND METHODS

Seventy-eight patients with locally advanced cervical cancer underwent DCE-MRI with Gd-DTPA before chemoradiotherapy. The pharmacokinetic Brix and Tofts models were fitted to contrast enhancement curves in all tumor voxels, providing histograms of several pharmacokinetic parameters (Brix: A(Brix), k(ep), k(el), Tofts: K(trans), ν(e)). A percentile screening approach including log-rank survival tests was undertaken to identify the clinically most relevant part of the intratumoral parameter distribution. Clinical endpoints were progression-free survival (PFS) and locoregional control (LRC). Multivariate analysis including FIGO stage and tumor volume was used to assess the prognostic significance of the imaging parameters.

RESULTS

A(Brix), k(el), and K(trans) were significantly (P<0.05) positively associated with both clinical LRC and PFS, while ν(e) was significantly positively correlated with PFS only. k(ep) showed no association with any endpoint. A(Brix) was positively correlated with K(trans) and ν(e), and showed the strongest association with endpoint in the log-rank testing. k(el) and K(trans) were independent prognostic factors in multivariate analysis with LRC as endpoint.

CONCLUSIONS

Parameters estimated by pharmacokinetic analysis of DCE-MR images obtained prior to chemoradiotherapy may be used for identifying patients at risk of treatment failure.

Imaging hypoxia in gliomas

Hypoxia plays a central role in tumour development, angiogenesis, growth and resistance to treatment. Owing to constant developments in medical imaging technology, significant advances have been made towards in vitro and in vivo imaging of hypoxia in a variety of tumours, including gliomas of the central nervous system. The aim of this article is to review the literature on imaging approaches currently available for measuring hypoxia in human gliomas and provide an insight into recent advances and future directions in this field. After a brief overview of hypoxia and its importance in gliomas, several methods of measuring hypoxia will be presented. These range from invasive monitoring by Eppendorf polarographic O(2) microelectrodes, positron electron tomography (PET) tracers based on 2-nitroimidazole compounds [(18)F-labelled fluoro-misonidazole ((18)F-MISO) or 1-(2-[((18))F]fluoro-1-[hydroxymethyl]ethoxy)methyl-2-nitroimidazole (FRP-170)], (64)Cu-ATSM Cu-diacetyl-bis(N4-methylthiosemicarbazone) (Cu-ATSM) or (99m)Tc- and (68)Ga-labelled metronidazole (MN) agents to advanced MRI methods, such as blood oxygenation level dependent (BOLD) MRI, oxygen-enhanced MRI, diffusion-weighted MRI (DWI-MRI), dynamic contrast-enhanced MRI (DCE-MRI) and (1)H-magnetic resonance spectroscopy.

Dynamic contrast-enhanced MR perfusion imaging of head and neck tumors at 3 Tesla

BACKGROUND

Dynamic contrast-enhanced (DCE) MR perfusion imaging allows assessment of vascular density and integrity of tumors. The purpose of this study was to determine the diagnostic efficacy of time intensity curve analysis on DCE MRI for characterization of head and neck tumors.

METHODS

Twenty patients underwent T1-weighted fast field echo DCE MRI with temporal resolution of 2.6 seconds. In total, 100 dynamic phases covering 20 slices were obtained in 4.5 minutes. Time to peak (TTP), relative maximum enhancement (RME) ratio, and relative washout ratio (RWO) were calculated.

RESULTS

Malignant tumors had a significantly lower RME (p = .025) and prolonged TTP with lower RWO than benign lesions. Postradiation changes had a significantly longer TTP (p = .024) and lower RWO (p = .007) than did postradiation recurrent tumors. Receiver operating characteristic (ROC) analysis revealed RWO had highest accuracy (area under the curve [AUC] = 1.0).

CONCLUSIONS

DCE MR perfusion imaging provides pivotal information regarding microcirculation, potentially improves differentiation of malignant tumor from postradiation changes.

Evaluation of pancreatic cancer by multiple breath-hold dynamic contrast-enhanced magnetic resonance imaging at 3.0T

OBJECTIVE

To investigate the microcirculation in pancreatic cancer by pharmacokinetic analysis of multiple breath-hold dynamic contrast-enhanced magnetic resonance imaging at 3.0T.

MATERIALS AND METHODS

Multiple breath-hold dynamic contrast-enhanced magnetic resonance imaging was performed in 40 healthy volunteers and 40 patients with pancreatic cancer proven by histopathology using an axial three-dimensions fat-saturated T1-weighted spoiled-gradient echo sequence at 3.0T. A two compartment model with T1 correction was used to quantify the transfer constant, the rate constant of backflux from the extravascular extracellular space to the plasma and the extravascular extracellular space fractional volume in pancreatic cancer, obstructive pancreatitis distal to the malignant tumor, adjacent pancreatic tissue proximal to the tumor and normal pancreas. All parameters were statistically analyzed.

RESULTS

Statistical differences were noticed in both the transfer constant (p=0.000075) and the rate constant of backflux (p=0.006) among different tissues. Both the transfer constant and the rate constant of backflux in pancreatic cancer were statistically lower than those in normal pancreas and adjacent pancreatic tissue (p<0.05). Both the transfer constant and the rate constant of backflux in obstructive pancreatitis were statistically lower than those in normal pancreas and adjacent pancreatic tissue (p<0.05). The extravascular extracellular space fractional volume in pancreatic cancer was statistically lager than that in normal pancreas (p=0.002).

CONCLUSION

Multiple breath-hold dynamic contrast-enhanced magnetic resonance imaging offers a useful technique to evaluate the microenvironment in pancreatic cancer at 3.0T. Compared to normal pancreas, pancreatic cancer has lower transfer constant, rate constant of backflux and larger extravascular extracellular space fractional volume.

Dynamic contrast-enhanced 3-T MR imaging in cervical cancer before and after concurrent chemoradiotherapy

OBJECTIVE

To investigate the changes of dynamic contrast-enhanced MR imaging (DCE-MRI) parameters at 3 T in cervical cancer patients before and after concurrent chemoradiotherapy (CCRT), and to correlate the parameters with final tumour response to therapy.

METHODS

Thirty-five patients with cervical cancer underwent DCE-MRI before CCRT, 4 weeks after starting therapy and at 1 month after the end of therapy. DCE-MRI parameters were calculated in the tumour and normal gluteus muscle. Final response to treatment as determined by changes in tumour size and volume was correlated with pre-treatment DCE-MRI parameters.

RESULTS

DCE-MRI parameters (i.e. K (trans), v (e) and k (ep)) in the tumours showed significant changes in response to CCRT (P < 0.05) and in particular K (trans) and v (e) demonstrated early significant increase (P < 0.01), but those in normal muscle did not show a significant difference (P > 0.05). Before therapy, the mean values of K (trans), k (ep), v (e) and v (p) in the tumours were significantly greater than those in muscle (P < 0.05). DCE-MRI parameters of the tumours at pre-treatment were not statistically associated with final tumour size or volume change.

CONCLUSION

DCE-MRI parameters may help evaluate early changes of cervical cancer to CCRT, but larger, more definitive studies are needed.

KEY POINTS

• DCE-MRI offers new insights into tumour behaviour. • Changes in tumour size lag behind biomarkers which improve quickly in responders. • DCE-MRI is a non-invasive imaging technique that can characterize tumour vasculature. • DCE-MRI of cervical cancer may be useful in monitoring changes with therapy.

Characterizing tumor heterogeneity with functional imaging and quantifying high-risk tumor volume for early prediction of treatment outcome: cervical cancer as a model

PURPOSE

Treatment response in cancer has been monitored by measuring anatomic tumor volume (ATV) at various times without considering the inherent functional tumor heterogeneity known to critically influence ultimate treatment outcome: primary tumor control and survival. This study applied dynamic contrast-enhanced (DCE) functional MRI to characterize tumors' heterogeneous subregions with low DCE values, at risk for treatment failure, and to quantify the functional risk volume (FRV) for personalized early prediction of treatment outcome.

METHODS AND MATERIALS

DCE-MRI was performed in 102 stage IB(2)-IVA cervical cancer patients to assess tumor perfusion heterogeneity before and during radiation/chemotherapy. FRV represents the total volume of tumor voxels with critically low DCE signal intensity (<2.1 compared with precontrast image, determined by previous receiver operator characteristic analysis). FRVs were correlated with treatment outcome (follow-up: 0.2-9.4, mean 6.8 years) and compared with ATVs (Mann-Whitney, Kaplan-Meier, and multivariate analyses).

RESULTS

Before and during therapy at 2-2.5 and 4-5 weeks of RT, FRVs >20, >13, and >5 cm(3), respectively, significantly predicted unfavorable 6-year primary tumor control (p = 0.003, 7.3 × 10(-8), 2.0 × 10(-8)) and disease-specific survival (p = 1.9 × 10(-4), 2.1 × 10(-6), 2.5 × 10(-7), respectively). The FRVs were superior to the ATVs as early predictors of outcome, and the differentiating power of FRVs increased during treatment.

DISCUSSION

Our preliminary results suggest that functional tumor heterogeneity can be characterized by DCE-MRI to quantify FRV for predicting ultimate long-term treatment outcome. FRV is a novel functional imaging heterogeneity parameter, superior to ATV, and can be clinically translated for personalized early outcome prediction before or as early as 2-5 weeks into treatment.

A five-colour colour-coded mapping method for DCE-MRI analysis of head and neck tumours

AIM

To devise a method to convert the time-intensity curves (TICs) of head and neck dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) data into a pixel-by-pixel colour-coded map for identifying normal tissues and tumours.

MATERIALS AND METHODS

Twenty-three patients with head and neck squamous cell carcinoma (HNSCC) underwent DCE-MRI. TIC patterns of primary tumours, metastatic nodes, and normal tissues were assessed and a program was devised to convert the patterns into a classified colour-coded map. The enhancement patterns of tumours and normal tissue structures were evaluated and categorized into nine grades (0-8) based on the predominance of coloured pixels on maps.

RESULTS

Five identified TIC patterns were converted into a colour-coded map consisting of red (maximum enhancement), brown (continuous slow rise-up), yellow (rapid wash-in and wash-out), green (rapid wash-in and plateau), and blue (rapid wash-in and rise-up). The colour-coded map distinguished all 21 primary tumours and 15 metastatic nodes from normal structures. Primary tumours and metastatic nodes were colour coded as predominantly yellow (grades 1-2) in 17/21 and 6/15, green (grades 3-5) in 3/21 and 5/15, and blue (grades 6-7) in 1/21 and 4/15, respectively. Vessels were coded red in 46/46 (grade 0) and muscles were coded brown in 23/23 (grade 8). Salivary glands, thyroid glands, and palatine tonsils were coded into predominantly yellow (grade 1) in 46/46 and 10/10 and 18/22, respectively.

CONCLUSION

DCE-MRI derived five-colour-coded mapping provides an objective easy-to-interpret method to assess the dynamic enhancement pattern of head and neck cancers.

Head and neck cancer as a model for advances in imaging prognosis, early assessment, and posttherapy evaluation

Novel noninvasive functional imaging methods are necessary to predict therapeutic outcome and thereby improve the ability to properly select patients for treatment with both conventional and targeted therapies, to better evaluate therapeutic effectiveness during the early phases of treatment, and to enhance a priori risk assessment for treatment induced toxicity. Functional metabolic imaging typically involves pretreatment baseline magnetic resonance imaging (MRI) and/or positron emission tomographic (PET) scans and performance of subsequent scans during and/or after treatment. Imaging parameter changes are routinely attributed to the intervening therapy and clinical outcomes subsequently correlated with these changes. The physiologic parameter(s) that best correlate with clinical outcome and the relative utility of MRI versus PET are unknown, however. Furthermore, tumor vascular physiology and metabolic parameters are heterogeneous and dynamic processes. Large daily fluctuations often occur in the absence of treatment. The magnitude of this temporal variability is not established for MRI or for PET. Routine and meaningful clinical application of functional imaging requires understanding and quantification of the intrinsic variability of the underlying biologic processes and a demonstration that treatment-induced changes exceed intrinsic temporal variation.

The promise of dynamic contrast-enhanced imaging in radiation therapy

Dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) and computed tomography (CT) scanning are emerging as valuable tools to quantitatively map the spatial distribution of vascular parameters, such as perfusion, vascular permeability, blood volume, and mean transit time in tumors and normal organs. DCE MRI/CT have shown prognostic and predictive value for response of certain cancers to chemotherapy and radiation therapy. DCE MRI/CT offer the promise of early assessment of tumor response to radiation therapy, opening a window for adaptively optimizing radiation therapy based upon functional alterations that occur earlier than morphologic changes. DCE MRI/CT has also shown the potential of mapping dose responses in normal organs and tissue for evaluation of individual sensitivity to radiation, providing additional opportunities to minimize risks of radiation injury. The evidence for potentially applying DCE MRI and CT for selection and delineation of radiation boost targets is growing. The clinical use of DCE MRI and CT scanning as a biomarker or even a surrogate endpoint for radiation therapy assessment of tumor and normal organs must consider technical validation issues, including standardization, reproducibility, accuracy and robustness, and clinical validation of the sensitivity and specificity for each specific problem of interest. Although holding great promise, to date, DCE MRI and CT scanning have not been qualified as a surrogate endpoint for radiation therapy assessment or for treatment modification in any prospective phase III clinical trial for any tumor site.

Functional Imaging for Assessing Tumor Response in Cancer of the Cervix

Treatment options for carcinoma of the cervix are guided by tumor stage, and include radical surgery, in cases where the tumor is confined to the cervix, or concurrent chemotherapy and radiotherapy. In those cases treated with chemoradiation, the ability to monitor the response to treatment in order to adapt the management plan during its course may be beneficial. This approach has the potential to offer an individualized treatment plan, allowing for differences in behavior between tumors to be addressed early, rather than a ‘one size fits all’ treatment approach. This article aims to review the use of evolving functional imaging techniques including diffusion-weighted MRI, dynamic contrast-enhanced MRI, and PET as tools for the evaluation of response to treatment of uterine cervical carcinoma.