Quantitative dynamic contrast-enhanced MR imaging analysis of complex adnexal masses: a preliminary study

Functional MR Imaging Techniques in Oncology in the Era of Personalized Medicine

DW and DCE MR imaging contribute significantly to diagnosis, treatment planning, response assessment, and prognosis in personalized cancer medicine. Nevertheless, the need for further standardization of these techniques needs to be addressed. Whole-body DW MR imaging is an exciting field; however, future studies need to investigate in more depth the biologic significance of the findings depicted, their prognostic relevance, and cost-effectiveness in comparison with MDCT and PET/CT. New MR imaging probes, such as targeted or activatable contrast agents and dynamic nuclear hyperpolarization, show great promise to further improve the care of patients with cancer in the near future.

MRI for discriminating metastatic ovarian tumors from primary epithelial ovarian cancers

AIMS

To find specific magnetic resonance imaging (MRI) features to differentiate metastatic ovarian tumors from primary epithelial ovarian cancers.

METHODS

Eleven cases with metastatic ovarian tumors and 26 cases with primary malignant epithelial ovarian cancers were retrospectively studied. All features such as patient characteristics, MRI findings and biomarkers were evaluated. The differences including laterality, configuration, uniformity of locules, diffusion weighted imaging (DWI) signal of solid components and enhancement of solid portions between metastatic ovarian tumors and primary epithelial ovarian cancers were compared by Fisher's exact test. Median age of patients, the maximum diameter of lesions and biomarkers were compared by the Mann-Whitney test.

RESULTS

Patients with metastatic ovarian tumors were younger than patients with primary epithelial ovarian cancers in the median age (P = 0.015). Patients with bilateral tumors in metastatic ovarian tumors were more than those of primary epithelial ovarian cancers (P = 0.032). The maximum diameter of lesions in metastatic ovarian tumors was smaller than that of primary epithelial ovarian cancers (P = 0.005). The locules in metastatic ovarian tumors were more uniform than those of primary epithelial ovarian cancers (P = 0.024). The enhancement of solid portions in metastatic ovarian tumors showed more moderate than that of primary epithelial ovarian cancers (P = 0.037). There was no statistically significant difference between the two groups in configuration, DWI signal of solid components and ascites. Biomarkers such as CA125 and human epididymis protein 4 (HE4) in metastatic ovarian tumors showed less elevated than that of primary epithelial ovarian cancers.

CONCLUSIONS

Significant differences between metastatic ovarian tumors and primary epithelial ovarian cancers were found in the median age of patients, laterality, the maximum diameter of lesions, uniformity of locules, enhancement patterns of solid portions and biomarkers. Metastatic ovarian tumors usually presented in the younger patients, smaller-sized, more bilateral lesions, more uniform of locules, more moderate enhancement of solid portions, and less elevated levels of CA125 and HE4 than those of primary epithelial ovarian cancers.

Added Value of Assessing Adnexal Masses with Advanced MRI Techniques

This review will present the added value of perfusion and diffusion MR sequences to characterize adnexal masses. These two functional MR techniques are readily available in routine clinical practice. We will describe the acquisition parameters and a method of analysis to optimize their added value compared with conventional images. We will then propose a model of interpretation that combines the anatomical and morphological information from conventional MRI sequences with the functional information provided by perfusion and diffusion weighted sequences.

Evaluation of gynecologic cancer with MR imaging, 18F-FDG PET/CT, and PET/MR imaging

MR imaging and (18)F-FDG PET/CT play central and complementary roles in the care of patients with gynecologic cancer. Because treatment often requires combinations of surgery, radiotherapy, and chemotherapy, imaging is central to triage and to determining prognosis. This article reviews the use of the 2 imaging modalities in the initial evaluation of 3 common cancers: uterine cervical, uterine endometrial, and epithelial ovarian. Imaging features that affect management are highlighted, as well as the relative strengths and weaknesses of the 2 modalities. Use of imaging after initial therapy to assess for recurrence and to plan salvage therapy is described. Newer functional and molecular techniques in MR imaging and PET are evaluated. Finally, we describe our initial experience with PET/MR imaging, an emerging technology that may prove to be a mainstay in personalized gynecologic cancer care.

[Unilateral borderline ovarian tumor and unilateral adenexectomy?]

To perform an adnexectomy in case of unilateral borderline tumor must consider the risk of recurrence, the preservation of fertility, and to integrate a global comprehensive management of a couple. Adnexectomy can be considering as a legitimate option when the woman desire a pregnancy. The risk of recurrence is low and the global survey high. Identification of woman with a high risk of recurrence is necessary. Adnexectomy can be considering as a legitimate option to preserve fertility in case of unilateral tumor. However, ovarian reserve data are missing after the surgery. Adnexectomy can be considering for the management of infertile woman with unilateral borderline tumor. IVF can be performed in the absence of any poor prognosis factor. Management with ovarian cryopreservation and In vitro Maturation remain unclear.

Intravoxel incoherent motion diffusion-weighted imaging in head and neck squamous cell carcinoma: assessment of perfusion-related parameters compared to dynamic contrast-enhanced MRI

PURPOSE

To investigate the correlation between perfusion-related parameters obtained with intravoxel incoherent motion (IVIM) and classical perfusion parameters obtained with dynamic contrast-enhanced (DCE) magnetic resonance imaging in patients with head and neck squamous cell carcinoma (HNSCC), and to compare direct and asymptotic fitting, the pixel-by-pixel approach, and a region of interest (ROI)-based approach respectively for IVIM parameter calculation.

MATERIALS AND METHODS

Seventeen patients with HNSCC were included in this retrospective study. All magnetic resonance (MR) scanning was performed using a 3T MR unit. Acquisition of IVIM was performed using single-shot spin-echo echo-planar imaging with three orthogonal gradients with 12 b-values (0, 10, 20, 30, 50, 80, 100, 200, 400, 800, 1000, and 2000). Perfusion-related parameters of perfusion fraction 'f' and the pseudo-diffusion coefficient 'D*' were calculated from IVIM data by using least square fitting with the two fitting methods of direct and asymptotic fitting, respectively. DCE perfusion was performed in a total of 64 dynamic phases with a 3.2-s phase interval. The two-compartment exchange model was used for the quantification of tumor blood volume (TBV) and tumor blood flow (TBF). Each tumor was delineated with a polygonal ROI for the calculation of f, f∙D* performed using both the pixel-by-pixel approach and the ROI-based approach. In the pixel-by-pixel approach, after fitting each pixel to obtain f, f∙D* maps, the mean value in the delineated ROI on these maps was calculated. In the ROI-based approach, the mean value of signal intensity was calculated within the ROI for each b-value in IVIM images, and then fitting was performed using these values. Correlations between f in a total of four combinations (direct or asymptotic fitting and pixel-by-pixel or ROI-based approach) and TBV were respectively analyzed using Pearson's correlation coefficients. Correlations between f∙D* and TBF were also similarly analyzed.

RESULTS

In all combinations of f and TBV, f∙D* and TBF, there was a significant correlation. In the comparison of f and TBV, a moderate correlation was observed only between f obtained by direct fitting with the pixel-by-pixel approach, whereas a good correlation was observed in the comparisons using the other three combinations. In the comparison of f∙D* and TBF, a good correlation was observed only with f∙D* obtained by asymptotic fitting with the ROI-based approach. In contrast, moderate correlations were observed in the comparisons using the other three combinations.

CONCLUSION

IVIM was found to be feasible for the analysis of perfusion-related parameters in patients with HNSCC. Especially, the combination of asymptotic fitting with the ROI-based approach was better correlated with DCE perfusion.

Dynamic contrast-enhanced magnetic resonance imaging: applications in oncology

Dynamic contrast-enhanced magnetic resonance imaging (DCE MRI) allows functional characterisation of tissue perfusion characteristics and acts as a biomarker for tumour angiogenesis. It involves serial acquisition of MRI images before and after injection of contrast, as such, tissue perfusion and permeability can be assessed based on the signal enhancement kinetics. The ability to evaluate whole tumour volumes in a non-invasive manner makes DCE MRI especially attractive for potential oncological applications. Here we provide an overview of the current research involving DCE MRI as a biomarker for the diagnosis and characterisation of malignancies, prediction of the therapeutic response and survival outcomes, as well as radiation therapy planning.

Imaging techniques for the pre-surgical diagnosis of adnexal tumours

A correct diagnosis of any adnexal mass is essential to triage women to appropriate treatment pathways. Several imaging techniques are available that may be used to provide an assessment of a mass before treatment, such as transvaginal ultrasonography, magnetic resonance imaging, computed tomography, and positron emission tomography combined with computed tomography. In this chapter, we focus in depth on the role of transvaginal ultrasonography, as current evidence suggests it is the most appropriate initial imaging investigation to identify and characterise any mass if present in women suspected of having adnexal pathology. Subjective assessment by an experienced ultrasound examiner is the optimal approach to diagnose masses, followed by risk models and rules developed by the International Ovarian Tumor Analysis study. A group of tumours has proven difficult to classify with transvaginal ultrasound, and remain a diagnostic challenge for which accurate second-stage tests would be of value. Some studies suggest that magnetic resonance imaging (MRI), compared with other imaging modalities, may play a role in the assessment of this cohort of 'difficult to classify' adnexal masses. These studies, however, did not report quality of transvaginal ultrasonography (i.e. experience level of the examiner) and lacked uniformity in describing the criteria used to define such 'difficult' masses. On the basis of standardised terminology developed by the International Ovarian Tumor Analysis study to describe adnexal masses, as well as prediction models and rules developed in the course of the study, we propose new criteria that we can use to clearly define complex or 'difficult to classify' adnexal masses to focus the role for second-line imaging tests, such as conventional magnetic resonance imaging combined with dynamic contrast-enhanced or diffusion-weighted sequences on masses where further tests other than ultrasonography would be of value.

Measurement of tumor blood flow in head and neck squamous cell carcinoma by pseudo-continuous arterial spin labeling: comparison with dynamic contrast-enhanced MRI

PURPOSE

To investigate the feasibility of tumor blood flow (TBF) measurement in head and neck squamous cell carcinoma (HNSCC) using pseudo-continuous arterial spin labeling (pCASL) in a comparison with dynamic contrast-enhanced (DCE) perfusion.

MATERIALS AND METHODS

We prospectively scanned 18 patients with HNSCC using 3T magnetic resonance imaging (MRI) with both pCASL and DCE perfusion. Quantitative TBF value in the whole-tumor region of interest (ROI), and regional TBF in the ROIs of the central and peripheral areas in the tumor were respectively measured. Relative TBF value in the whole-tumor ROI was also calculated. We determined the correlation and agreement between each measured TBF by pCASL and DCE perfusion using Pearson's correlation coefficients, intraclass correlation coefficients (ICC), and Bland-Altman analysis.

RESULTS

In the whole-tumor ROIs, significant correlation was observed between the absolute TBF values (r = 0.72, P < 0.01), with an ICC of 0.72; moreover, higher correlation was observed in the relative TBF (r = 0.79). The correlation was higher in the peripheral ROI (r = 0.70) than the central ROI (r = 0.65), with an ICC of 0.62 and 0.54, respectively. Bland-Altman plots revealed the underestimation of TBF by pCASL in central ROIs.

CONCLUSION

TBF measurement by pCASL was feasible in patients with HNSCC.

Value of dynamic contrast-enhanced MRI for tissue characterization of ovarian teratomas: correlation with histopathology

AIM

To analyse the value of double contrast-enhanced (DCE) magnetic resonance imaging (MRI) in addition to conventional MRI to characterize ovarian teratomas subtypes with histological correlation.

MATERIALS AND METHODS

From January 2005 to December 2008, 38 women undergoing MRI and subsequent resection of ovarian teratomas were identified [40 mature cystic teratomas (MCT), two struma ovarii, three immature teratomas]. MRI images were analysed blindly by two radiologists according to morphological and vascular abnormalities. An experienced histopathologist reviewed all slides to determine the presence and histological composition of Rokitansky protuberances.

RESULTS

Thirty-one MCT (77%) had at least one small, regular Rokitansky protuberance presenting at an acute angle with the cyst wall. Ten out of 31 MCT did not display any enhancement on contrast-enhanced MRI related to sebaceous glands, adipose lobules, keratin, and pilosebaceous adnexa at histology. Three different time-intensity curve (TIC), types 1, 2, and 3, were related to presence of smooth muscular cells and fibrous, neuroglial, or thyroid tissue, respectively, found at histology of MCT. Type 3 TIC was also present in one struma ovarii and two immature teratomas.

CONCLUSION

TIC types are related to the specific content of the solid tissue of ovarian teratomas but cannot be used to differentiate benign and malignant ovarian teratomas.

The added role of MR imaging in treatment stratification of patients with gynecologic malignancies: what the radiologist needs to know

Many treatment options are available to patients with endometrial, cervical, or ovarian cancer. Magnetic resonance (MR) imaging plays an important role in the patient journey from the initial evaluation of the extent of the disease to appropriate treatment selection and follow-up. The purpose of this review is to highlight the added role of MR imaging in the treatment stratification and overall care of patients with endometrial, cervical, or ovarian cancer. Several MR imaging techniques used in evaluation of patients with gynecologic malignancies are described, including both anatomic MR imaging sequences (T1- and T2-weighted sequences) and pulse sequences that characterize tissue on the basis of physiologic features (diffusion-weighted MR imaging), dynamic contrast agent-enhanced MR imaging, and MR spectroscopy. MR imaging findings corresponding to the 2009 revised International Federation of Gynecology and Obstetrics staging of gynecologic malignancies are also described in detail, highlighting possible pearls and pitfalls of staging. With the growing role of the radiologist as a core member of the multidisciplinary treatment planning team, it is crucial for imagers to recognize that MR imaging has become central in tailoring treatment options and therapy in patients with gynecologic malignancies.

Imaging strategy for early ovarian cancer: characterization of adnexal masses with conventional and advanced imaging techniques

Early detection of ovarian cancer remains crucial for improving patient survival rates. However, early-stage disease is often asymptomatic, and population screening is currently unproven. Adnexal masses may be incidentally detected, but most are identified at ultrasonography (US) in patients who are symptomatic, and most may be characterized as benign or malignant. Indices are available to estimate the risk of malignancy on the basis of clinical and US findings. However, adnexal masses remain indeterminate in some cases, with some benign lesions demonstrating features of malignancy at US. In these cases, use of magnetic resonance (MR) imaging improves the ability to characterize adnexal masses and reduces the number of indeterminate lesions. Establishing the likelihood of malignancy on the basis of imaging features is important to the preoperative detection of early ovarian cancer and profoundly influences referral and management pathways. Conventional and contrast material-enhanced MR imaging are used to evaluate morphologic features, including lesion complexity, signal intensity, and enhancement of solid areas. At dynamic contrast-enhanced MR imaging with semiquantitative analysis, early enhancement characteristics may help differentiate some complex benign and malignant lesions. Diffusion-weighted imaging has a limited but useful role in evaluating adnexal masses: Those with a hypointense solid area on both diffusion-weighted (b = 1000 sec/mm²) and T2-weighted images are likely benign, whereas those that are hyperintense on diffusion-weighted images (b = 1000 sec/mm²) with intermediate signal intensity on T2-weighted images are likely malignant.

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.

Fertility and borderline ovarian tumor: a systematic review of conservative management, risk of recurrence and alternative options

BACKGROUND

The aim of this systematic review was to evaluate the fertility outcome after borderline ovarian tumor (BOT) management and the results of conservative management, risk of recurrence and alternative options.

METHODS

The search strategy was based on relevant terms concerning BOT using Medline and the Central Cochrane Library. Both early and advanced stages of serous and mucinous BOT were included, but not rare entities such as endometrioid, Brenner or clear-cell BOT because of their low incidence. We considered all articles-case reports, original studies, meta-analyses and reviews-in English and French.

RESULTS

Overall, 230 articles were screened of which 120 were retained for review. Most pregnancies were spontaneous but some data were obtained from studies analyzing the contribution of assisted reproductive technology (ART). However, not all studies differentiated spontaneous pregnancy from those obtained after fertility treatment including ovulation induction, intrauterine insemination and IVF. Conservative management of early stage BOT resulted in a pooled estimate for spontaneous pregnancy rate of 54% with a low risk of lethal recurrence (pooled estimate: 0.5%). In patients with advanced stage BOT, the spontaneous pregnancy rates was lower (34% in the single series reporting pregnancy rate in this context) and the risk of lethal recurrence increased (pooled estimate: 2%).

CONCLUSIONS

This systematic review underlines that fertility subsequent to treatment of BOT depends mainly on histology and initial staging to distinguish early from advanced stages. In patients with advanced stage BOT, several alternative options to conservative management are available to allow patients to conceive without compromising their prognosis.