Diffusion MR imaging for monitoring treatment response

Mass-forming intrahepatic cholangiocarcinoma: Can diffusion-weighted imaging predict microvascular invasion?

BACKGROUND

Microvascular invasion (MVI) is a risk factor influencing the survival rate of patients with mass-forming intrahepatic cholangiocarcinoma (IMCC).

PURPOSE

To investigate whether diffusion-weighted imaging (DWI) could be useful in predicting MVI of IMCC.

STUDY TYPE

Retrospective.

SUBJECTS

Eighty patients with surgically resected single IMCC (21 MVI-positive lesions and 59 MVI-negative lesions).

FIELD STRENGTH/SEQUENCE

Preoperative hepatic MRI (1.5T), including T₁ - and T₂ -weighted images (T₁ WI, T₂ WI), DWI, and dynamic enhancement imaging.

ASSESSMENT

Morphologic characteristics including contour of the lesion, biliary dilation and hepatic capsule retraction, signal features on T₁ WI, T₂ WI, and DWI, and dynamic enhancement patterns were qualitatively evaluated. The quantitative analysis was performed for the size and apparent diffusion coefficient (ADC) values.

STATISTICAL TESTS

Chi-square test, Fisher's exact test, and the independent t-test were used for univariate analysis to determine the relationships between these radiological parameters and the presence of MVI. Logistic regression analysis was used to identify the independent predictors of MVI among these radiological parameters. Receiver operating characteristic curve analysis was performed to evaluate their diagnostic performance.

RESULTS

Larger tumor size (P = 0.006) and higher ADC values (P < 0.001) were positively correlated with MVI. Multivariate logistic regression analysis demonstrated that the ADC value (odds ratio, 3.099; P = 0.001) was an independent predictor for MVI of IMCC. The ADC value for MVI of IMCC showed an area under the receiver operating characteristic curve of 0.782 (optimal cutoff value was 1.59 × 10^-3 mm² /s).

DATA CONCLUSION

Larger tumor size was associated with MVI and higher ADC values can be a useful predictor of MVI during the preoperative evaluation of IMCC.

LEVEL OF EVIDENCE

1 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2019;50:315-324.

Imaging in Endoscopic Cranial Skull Base and Pituitary Surgery

Endoscopic endonasal approaches have widely accepted techniques for managing benign and malignant processes along the entire ventral skull base with similar or better results compared with open procedures, but with lower rates of complication. Managing pathology affecting the skull base can be challenging because of complex anatomy and the proximity of critical neurovascular structures. Postoperative imaging can be challenging, because of surgical alterations of normal anatomy and the now common use of complex reconstruction techniques. Understanding the normal imaging appearance of skull base reconstruction is important for accurate postoperative interpretation and delineation between normal reconstructive tissue and recurrent neoplasm.

Application value of diffusion weighted whole body imaging with background body signal suppression in monitoring the response to treatment of bone marrow involvement in lymphoma

PURPOSE

To investigate the application value of diffusion weighted whole body imaging with background body signal suppression (DWIBS) in monitoring the response to treatment of bone marrow involvement in lymphoma.

MATERIALS AND METHODS

Twenty-one lymphoma patients with bone marrow involvement underwent 1.5 Tesla DWIBS before chemotherapy and after the second chemotherapy session (median interval, 8 weeks; range 7-11 weeks). Apparent diffusion coefficient (ADC) values of bone marrow lesions were measured before and after treatment. The difference in ADC values before and after treatment in responders and nonresponders was analyzed.

RESULTS

Seventy-three cases of bone marrow lesions were diagnosed in 21 lymphoma patients before the treatment. After the second chemotherapy session, 18 patients (57 lesions) and 3 patients (9 lesions) were categorized into the responder and nonresponder group, respectively. The mean pretreatment ADC value of all lesions was 0.90 ± 0.39 × 10^-3 mm² /s, of which the mean ADC values of the responder group and nonresponder group were 0.92 ± 0.40 × 10^-3 mm² /s and 0.79 ± 0.29 × 10^-3 mm² /s, respectively (between-group difference: t = -0.94; P = 0.351). The posttreatment ADC value of the responder group significantly increased (66.39% ± 83.11%; P < 0.001) while the posttreatment ADC value of the nonresponder group slightly increased (5.32% ± 17.31%). The difference in the rate of change of ADC values in the responder and nonresponder groups before and after the treatment was significant (P < 0.05).

CONCLUSION

DWIBS in combination with the measurement of ADC values enabled a good short-term response evaluation for bone marrow involvement in lymphoma. However, the pretreatment ADC value indicated no significant predictive value for responses to the treatment. J. Magn. Reson. Imaging 2016;44:1522-1529.

The comprehensive neuro-oncology data repository (CONDR): a research infrastructure to develop and validate imaging biomarkers

BACKGROUND

Advanced imaging methods have the potential to serve as quantitative biomarkers in neuro-oncology research. However, a lack of standardization of image acquisition, processing, and analysis limits their application in clinical research. Standardization of these methods and an organized archival platform are required to better validate and apply these markers in research settings and, ultimately, in clinical practice.

OBJECTIVE

The primary objective of the Comprehensive Neuro-oncology Data Repository (CONDR) is to develop a data set for assessing and validating advanced imaging methods in patients diagnosed with brain tumors. As a secondary objective, informatics resources will be developed to facilitate the integrated collection, processing, and analysis of imaging, tissue, and clinical data in multicenter clinical trials. Finally, CONDR data and informatics resources will be shared with the research community for further analysis.

METHODS

CONDR will enroll 200 patients diagnosed with primary brain tumors. Clinical, imaging, and tissue-based data are obtained from patients serially, beginning with diagnosis and continuing over the course of their treatment. The CONDR imaging protocol includes structural and functional sequences, including diffusion- and perfusion-weighted imaging. All data are managed within an XNAT-based informatics platform. Imaging markers are assessed by correlating image and spatially aligned pathological markers and a variety of clinical markers.

EXPECTED OUTCOMES

CONDR will generate data for developing and validating imaging markers of primary brain tumors, including multispectral and probabilistic maps.

DISCUSSION

CONDR implements a novel, open-research model that will provide the research community with both open-access data and open-source informatics resources.

In vivo assessment of the vascular disrupting effect of M410 by DCE-MRI biomarker in a rabbit model of liver tumor

The present study aimed to prospectively monitor the vascular disrupting effect of M410 by dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) in rabbits with VX2 liver tumors. Twenty-eight rabbits bearing VX2 tumors in the left lobe of the liver were established and randomly divided into treatment and control groups, intravenously injected with 25 mg/kg M410 or sterile saline, respectively. Conventional and DCE-MRI data were acquired on a 3.0-T MR unit at pretreatment, 4 h, 1, 4, 7 and 14 days post-treatment. Histopathological examinations [hematoxylin and eosin (H&E) and CD34 immunohistochemisty staining] were performed at each time point. The dynamic changes in tumor volume, kinetic DCE-MRI parameter [volume transfer constant (Ktrans)] and histological data were evaluated. Tumors grew slower in the M410 group 4-14 days following treatment, compared with rapidly growing tumors in the control group (P<0.05). At 4 h, 1 and 4 days, Ktrans significantly decreased in the M410 group compared with that in the control group (P<0.05). However, Ktrans values were similar in the two groups for the other time points studied. The changes in DCE-MRI parameters were consistent with the results obtained from H&E and CD34 staining of the tumor tissues. DCE-MRI parameter Ktrans may be used as a non-invasive imaging biomarker to monitor the dynamic histological changes in tumors following treatment with the vascular targeting agent M410.