Underwent Dynamic Contrast-enhanced MRI Research Articles

Dynamic Contrast-enhanced MRI Quantification of Altered Vascular Permeability in Autoimmune Encephalitis.

Background Blood-brain barrier (BBB) permeability change is a possible pathologic mechanism of autoimmune encephalitis. Purpose To evaluate the change in BBB permeability in patients with autoimmune encephalitis as compared with healthy controls by using dynamic contrast-enhanced (DCE) MRI and to explore its predictive value for treatment response in patients. Materials and Methods This single-center retrospective study included consecutive patients with probable or possible autoimmune encephalitis and healthy controls who underwent DCE MRI between April 2020 and May 2021. Automatic volumetric segmentation was performed on three-dimensional T1-weighted images, and volume transfer constant (Ktrans) values were calculated at encephalitis-associated brain regions. Ktrans values were compared between the patients and controls, with adjustment for age and sex with use of a nonparametric approach. The Wilcoxon rank sum test was performed to compare Ktrans values of the good (improvement in modified Rankin Scale [mRS] score of at least two points or achievement of an mRS score of ≤2) and poor (improvement in mRS score of less than two points and achievement of an mRS score >2) treatment response groups among the patients. Results Thirty-eight patients with autoimmune encephalitis (median age, 38 years [IQR, 29-59 years]; 20 [53%] female) and 17 controls (median age, 71 years [IQR, 63-77 years]; 12 [71%] female) were included. All brain regions showed higher Ktrans values in patients as compared with controls (P < .001). The median difference in Ktrans between the patients and controls was largest in the right parahippocampal gyrus (25.1 × 10-4 min-1 [95% CI: 17.6, 43.4]). Among patients, the poor treatment response group had higher baseline Ktrans values in both cerebellar cortices (P = .03), the left cerebellar cortex (P = .02), right cerebellar cortex (P = .045), left cerebral cortex (P = .045), and left postcentral gyrus (P = .03) than the good treatment response group. Conclusion DCE MRI demonstrated that BBB permeability was increased in all brain regions in patients with autoimmune encephalitis as compared with controls, and baseline Ktrans values were higher in patients with poor treatment response in the cerebellar cortex, left cerebral cortex, and left postcentral gyrus as compared with the good response group. © RSNA, 2024 Supplemental material is available for this article. See also the editorial by Filippi and Rocca in this issue.

Assessment of Response to Neoadjuvant Systemic Treatment in Triple-Negative Breast Cancer Using Functional Tumor Volumes from Longitudinal Dynamic Contrast-Enhanced MRI

Early assessment of neoadjuvant systemic therapy (NAST) response for triple-negative breast cancer (TNBC) is critical for patient care in order to avoid the unnecessary toxicity of an ineffective treatment. We assessed functional tumor volumes (FTVs) from dynamic contrast-enhanced (DCE) MRI after 2 cycles (C2) and 4 cycles (C4) of NAST as predictors of response in TNBC. A group of 100 patients with stage I-III TNBC who underwent DCE MRI at baseline, C2, and C4 were included in this study. Tumors were segmented on DCE images of 1 min and 2.5 min post-injection. FTVs were measured using the optimized percentage enhancement (PE) and signal enhancement ratio (SER) thresholds. The Mann-Whitney test was used to compare the performance of the FTVs at C2 and C4. Of the 100 patients, 49 (49%) had a pathologic complete response (pCR) and 51 (51%) had a non-pCR. The maximum area under the receiving operating characteristic curve (AUC) for predicting the treatment response was 0.84 (p < 0.001) for FTV at C4 followed by FTV at C2 (AUC = 0.82, p < 0.001). The FTV measured at baseline was not able to discriminate pCR from non-pCR. FTVs measured on DCE MRI at C2, as well as at C4, of NAST can potentially predict pCR and non-pCR in TNBC patients.

Choroid Plexus Volume and Permeability at Brain MRI within the Alzheimer Disease Clinical Spectrum.

Background Mounting evidence suggests that the choroid plexus (CP) plays an important role in the pathophysiology of Alzheimer disease (AD), but its imaging profile in cognitive impairment remains unclear. Purpose To evaluate CP volume, permeability, and susceptibility by using MRI in patients at various stages of cognitive impairment. Materials and Methods This retrospective study evaluated patients with cognitive symptoms who underwent 3.0-T MRI of the brain, including dynamic contrast-enhanced (DCE) imaging and quantitative susceptibility mapping (QSM), between January 2013 and May 2020. CP volume was automatically segmented using three-dimensional T1-weighted sequences; the volume transfer constant (ie, Ktrans) and fractional plasma volume (ie, Vp) were determined using DCE MRI, and susceptibility was assessed using QSM. The effects of CP volume, expressed as the ratio to intracranial volume, on cognition were evaluated using multivariable linear regression adjusted for age, sex, education, apolipoprotein E ε4 allele status, and volumetric measures. Results A total of 532 patients with cognitive symptoms (mean age, 72 years ± 9 [SD]; 388 women) were included: 78 with subjective cognitive impairment (SCI), 158 with early mild cognitive impairment (MCI), 149 with late MCI, and 147 with AD. Among these, 132 patients underwent DCE MRI and QSM. CP volume was greater in patients at more severe stages (ratio of intracranial volume × 103: 0.9 ± 0.3 for SCI, 1.0 ± 0.3 for early MCI, 1.1 ± 0.3 for late MCI, and 1.3 ± 0.4 for AD; P < .001). Lower Ktrans (r = -0.19; P = .03) and Vp (r = -0.20; P = .02) were negatively associated with CP volume; susceptibility was not (r = 0.15; P = .10). CP volume was negatively associated with memory (B = -0.67; standard error of the mean [SEM], 0.21; P = .01), executive function (B = -0.90; SEM, 0.31; P = .01), and global cognition (B = -0.82; SEM, 0.32; P = .01). Conclusion Among patients with cognitive symptoms, larger choroid plexus volume was associated with severity of cognitive impairment in the Alzheimer disease spectrum. Published under a CC BY 4.0 license. Online supplemental material is available for this article. See also the editorial by Chiang in this issue.

Value of dynamic and DWI MRI in evaluation of HCC viability after TACE via LI-RADS v2018 diagnostic algorithm

BackgroundDetection of the value of DCE (dynamic contrast enhanced) MRI and DWI (diffusion-weighted imaging) in follow-up of treatment response for HCC (hepatocellular carcinoma) lesions post TACE (trans-arterial chemo-embolization) through LI-RADS v2018 algorithmic approach.ResultsA prospective study was performed on 30 patients with 41 treated hepatic focal lesions. The patients underwent DCE MRI with DWI in less than 1-month duration following TACE procedure and were radiologically assessed to observe tumoral post treatment response; then, another follow-up after another 3 months later was done for non-viable, equivocal, and non-evaluable post treatment response categories. Statistical analysis showed that DCE MRI had 100% level of sensitivity, specificity of 95.24%, PPV of 95.00%, and NPV of 100% with an overall agreement of 97.50%. While on the other hand, statistics showed that DWI has 52.63% level of sensitivity, specificity of 90.48%, PPV of 83.33%, PPV of 67.86%, and NPV of 72.50%.The difference between non-viable and viable groups’ ADC variables was found statistically significant at P value < 0.001, and best cut off value that augments sensitivity and specificity is 1.35. At this ADC value, sensitivity reaches 78.9% and specificity is 85.7%.ConclusionsOur study showed that DCE MRI has 100% level of sensitivity via application of LI-RADS v2018 diagnostic algorithmic approach while DWI alone has 52.63% level of sensitivity, yet it can enhance the diagnostic confidence of DCE MRI for post treatment response viability detection.

MRI predictors of tumor-positive margins after breast-conserving surgery

PurposeThe purpose of this study is to identify predictors of tumor-positive surgical margins after breast-conserving surgery on dynamic contrast-enhanced (DCE) MRI. Materials and methodsWe conducted a retrospective study of consecutive women who underwent DCE MRI before breast-conserving surgery from 2005 to 2014. Patient demographics, indication for surgery, MRI findings, biopsy pathology results, and surgical outcomes were reviewed. The unpaired t-test and chi-square test were used to compare the positive and negative margins groups. Results554 women (mean age, 56; range, 26–90) underwent DCE MRI before 575 breast-conserving surgeries for invasive carcinoma (n = 473) or ductal carcinoma in situ (DCIS) (n = 102). Positive margins requiring re-excision occurred in 19.7% (93/473) of surgeries for invasive carcinoma and 31.4% (32/102) of surgeries for DCIS. For invasive carcinoma surgeries, positive margins were more common when MRI demonstrated the finding of non-mass enhancement (NME) rather than the finding of enhancing mass (33.8% [22/65] versus 16.9% [61/360], p < 0.01). Tumor size on MRI was significantly larger in the positive margins group (2.5 cm versus 1.9 cm, p < 0.001). Positive margins were more common with invasive lobular rather than invasive ductal histology at core biopsy (38.3% [18/47] versus 16.0% [56/350], p < 0.001). For DCIS surgeries, there were no significant differences in positive margin rates related to MRI features. ConclusionFor invasive carcinoma surgeries, positive margins are associated with NME on MRI, larger tumor size on MRI, and lobular histology at core biopsy. These findings may be used to predict which patients are at risk for positive margins after breast-conserving surgery.

Utility of semiquantitative parameters to differentiate benign and malignant focal hepatic lesions

ObjectiveAny distinction and the usefulness of semiquantitative parameters derived from dynamic-contrast-enhanced (DCE) MRI obtained with extracellular gadolinium contrast agent in hemangiomas, hepatocellular carcinomas (HCC) and metastases of the liver was studied prospectively. MethodsSeventy-four focal liver lesions (consisted of 34 hemangiomas, 23 HCC, and 17 metastases) of the 37 patients underwent DCE–MRI (six phases). Functional coloured maps and subsequently semiquantitative parameters were obtained using the FuncTool. Maximum and average (avg) values of mean time to enhancement (MTE), positive enhancement integral (PEI), time to peak (TP), maximum slope of increase (MSI), maximum slope of decrease (MSD) values were measured by placing the region of interest. The diagnosis of HCC and metastases were proven histopathologically and/or clinically. ResultsThe mean values of the paremeters were: In hemangiomas, avgMTE: 271.2±4.7; avgPEI: 840.3±77.3; avgTP: 146.6±13.1; avgMSI: 999.1±108.4; avgMSD: 254.1±30.4. In HCC, avgMTE: 246±3.6; avgPEI: 424.9±31.6; avgTP: 132.8±9.5; avgMSI: 484.1±36.5; avgMSD: 109.1±13.3. In metastases, avgMTE: 248.1±8.2, avgPEI: 453.9±39.6; avgTP: 142.8±13.9; avgMSI: 472.6±50.4 and avg MSD: 200.1±38.2. Both maximum and avg values of MTE, PEI, MSI, and MSD were significantly higher in hemangiomas (P<.05). The most significant difference was found in avgPEI with 82.1% sensitivity and 67.6% specificity when 570 cutoff value was considered. The values however were not significantly different among HCC and metastases (P>.05). ConclusionsSemiquantitative DCE–MRI parameters provide useful, complementary, and quantitative information. This technique increases diagnostic value of extracellular gadolinium contrast agent to characterize focal liver lesions and may be useful for follow-up after local–regional therapies.

155P - Effect of Bevacizumab on Tumour 5-Fluorouracil Concentration and Microcirculatory Parameters Obtained by Dynamic Contrast-Enhanced MRI in a Hepatocellular Carcinoma Xenograft Model

ABSTRACT Introduction Vascular endothelial growth factor (VEGF) is expressed by tumours to promote angiogenesis. Clinical trials of anti-VEGF therapy combined with chemotherapy demonstrate improvement in survival. We investigate the effect of bevacizumab (bev), a humanized monoclonal antibody that inhibits VEGF-A, on tumour 5-fluorouracil (5FU) concentration in a hepatocellular carcinoma (HCC) xenograft model, together with changes in tumour microcirculatory parameters obtained by dynamic contrast-enhanced (DCE) MRI. Methods 48 immunodeficient mice implanted with subcutaneous HCC xenografts were first injected with bev (1mg/kg or 10mg/kg) or omalizumab (control). 1 day later, they received 5FU and were sacrificed. Tumour and plasma 5FU concentration was measured by liquid chromatography-mass spectrometry. A subset of 17 mice underwent DCE MRI with gadolinium contrast at baseline and one day after bev/omalizumab injection. Scans employed a three-dimensional spoiled gradient recalled sequence with tracer concentration estimated using variable flip-angle technique. Data analysis employed a conventional two-compartment tracer kinetic model. Results Tumour 5FU concentration (µg/g) was significantly lower 1 day after bev (10mg/kg) compared to control (8.4 vs 21.6, p = 0.027). However, there was no significant difference in plasma 5FU concentration between the bev and control groups. Following bev (10mg/kg), DCE MRI measurements of tumour intravascular blood volume reduced by 38.3% (p = 0.01); there was no significant change in DCE-MRI parameters in the control group. Following bev (1mg/kg), tumour permeability-surface area product (ml/100ml/min) correlated with tumour 5FU concentration (r2 = 0.84, p = 0.01). Conclusion Bev causes vascular shutdown consistent with its anti-angiogenic mode of action. Reduced tumour 5FU concentration suggests that the reported synergism between anti-VEGF and chemotherapy may not be attributable to improved drug delivery at this early time point. DCE-MRI may play a role as a biomarker for tumour drug concentration following anti-VEGF therapy. Disclosure All authors have declared no conflicts of interest.

An exploratory study into the role of dynamic contrast-enhanced (DCE) MRI metrics as predictors of response in head and neck cancers

To assess the efficacy of dynamic contrast-enhanced magnetic resonance imaging (DCE MRI) in prediction of the response to treatment in patients with head and neck cancers (HNCs). Twenty-one patients with advanced HNC, suitable for concurrent chemoradiotherapy underwent DCE MRI, for the quantification of blood flow (BF) and volume (BV). All the patients received radical doses of conventionally fractionated radiotherapy up to a dose of 70Gy along with concurrent weekly cisplatin. The values of BV and BF were higher in complete responders as compared to partial responders at primary as well as nodes. Both BF and BV were found to be significantly higher in patients with high T-stage as compared to patients with lower T-stage. DCE metrics can be used as a predictor of response to treatment in locally advanced HNCs after validation of these observations in a larger number of patients.

Sphenoid sinus ectopic pituitary adenomas: CT and MRI findings

Ectopic pituitary adenomas (EPAs) are rare lesions. The purpose of this study was to describe the CT and MRI features of sphenoid sinus EPAs. Eight patients with histology-proven EPAs in the sphenoid sinus, all of whom underwent CT and MRI, were reviewed retrospectively. The following imaging features were analysed: (i) size, (ii) margin, (iii) CT attenuation characteristics and (iv) MRI signal intensity. In addition, the involvement of adjacent structures and the time-intensity curve (TIC) of dynamic contrast-enhanced (DCE) MRI were analysed. All EPAs had well-defined margins and showed no relationship to the intrasellar pituitary gland. The mean size was 28 mm (range, 20-46 mm). On non-enhanced CT, the lesions appeared isodense to grey matter in 7 (88%) patients and hypodense in 1 (12%) patient. Only two patients underwent post-contrast CT, and they showed moderate enhancement. On T1 weighted images, EPAs appeared isointense in 6 (75%) patients and hypointense in 2 (25%). On T2 weighted images, the lesions appeared hyperintense in 2 (25%) patients and isointense in 6 (75%). EPAs showed mild to moderate heterogeneous contrast enhancement and exhibited a cribriform-like appearance. Two patients underwent DCE MRI; the TIC showed a rapidly enhancing and slow washout pattern. The following features were also seen: an empty sella, bone changes and involvement of the cavernous sinus (5 patients; 62.5%). In conclusion, a high index of suspicion for EPA and a familiarity with the imaging findings may help to diagnose this rare entity accurately.

Dynamic contrast‐enhanced (DCE) derived transfer coefficient (ktrans) is a surrogate marker of matrix metalloproteinase 9 (MMP‐9) expression in brain tuberculomas

To correlate dynamic contrast-enhanced (DCE) MRI derived perfusion indices with immunohistochemically obtained vascular endothelial growth factor (VEGF) and matrix metalloproteinase-9 (MMP-9) in a cellular fraction of brain tuberculomas (BT). Thirteen BT patients underwent DCE MRI. Perfusion indices (cerebral blood volume [CBV], transfer coefficient [ktrans] and leakage [ve]) maps were generated for the quantitative analysis. The CBV was corrected for the leaky blood-brain barrier (BBB). The relative CBV (rCBV), ktrans, and ve were calculated by placing 10 regions of interest (ROIs) showing the highest values in the lesion. The percentage area of VEGF and percentage area of MMP-9 and microvessel density (MVD) were quantified from 10 fields per lesion with maximal expression of the excised BT. Pearson correlation analysis between physiological indices and quantitative VEGF, MMP-9, and MVD was performed for each ROI. The average value of rCBV, ktrans, ve, VEGF, MMP-9, and MVD were 3.53+/-0.37, 2.04+/-0.40 min(-1), 0.71+/-0.09, 12.51+/-2.56, 18.09+/-2.06, 10.87+/-1.99, respectively. The ktrans (r=0.918, P<0.001) and ve (r=0.899, P<0.001) showed significant correlation with MMP-9, while rCBV correlated significantly with MVD (r=0.962, P<0.001) and VEGF (r=0.868, P<0.001). We conclude that the expression of MMP-9, a marker of BBB disruption and disease activity in BT correlates with DCE-derived ktrans and thus has the potential to be used as its surrogate marker.

Independent component analysis of dynamic contrast‐enhanced magnetic resonance images of breast carcinoma: A feasibility study

To study the possibility of using independent component analysis (ICA) to identify breast lesions as separate hemodynamic sources on dynamic contrast-enhanced (DCE) MR images, as depicted by the passage of contrast medium. Six patients who were histopathologically confirmed with breast carcinoma underwent DCE MRI with 5 precontrast and 60 postcontrast scans at a time-resolution of 8 s. A spatial ICA algorithm was applied on the DCE MRI data set to extract spatial component maps corresponding to source locations with different signal time-intensity patterns. To verify the present hypothesis of the ability of ICA to reveal tumor voxels as a separate hemodynamic phase, tumor margins were outlined by an experienced radiologist who was blinded from the ICA results, and the manual outlines were compared with the ICA maps. Consistently for each of the six patient study cases, it was found that ICA yields a tumor component map associated with typical tumor enhancement patterns of rapid enhancement with washout or plateau. Tumor outlines manually drawn by the radiologist were in good agreement with the tumor locations depicted in the tumor component maps. ICA may provide an objective method for identifying the outlines of enhancing breast tumors on DCE MR images and to automatically extract the tumor signal intensity-time curve for subsequent tracer kinetics analysis.