Apparent Diffusion Coefficient Ratio Research Articles

The value of clinical parameters combined with magnetic resonance imaging (MRI) features for preoperatively distinguishing different subtypes of uterine sarcomas: An observational study (STROBE compliant).

To investigate clinical parameters combined with magnetic resonance imaging (MRI) features including apparent diffusion coefficient (ADC) values in preoperative identification of different subtypes of uterine sarcomas including uterine leiomyosarcoma (LMS), endometrial stromal sarcoma (ESS), and carcinosarcoma (CS).Data from 71 patients with uterine sarcoma confirmed by surgery and pathology were collected. The clinical characteristics, conventional MRI features, mean ADC values, minimum ADC values, and lesion-muscle ADC ratio (rADC) values were compared with different subtypes of uterine sarcomas.Age, clinical manifestation, tumor location, shape, and T1-weighted image (T1WI) signals were significantly different between CS and LMS or ESS (all P < .01). The presence of band sign was significantly higher in ESS than in LMS or CS (both P < .001). The cystic change or necrosis and enhancement could help to differentiate LMS from ESS or CS (both P < .02). Significant differences were observed in T2-weighted image (T2WI) signals of the solid components of LMS compared with CS (P < .001). There was a significant difference between ESS and CS in the rADC values (P = .004).Clinical parameters combined with MRI features could help narrowing preoperative diagnostic possibilities in distinguishing subtypes of uterine sarcomas. These findings may be beneficial in helping guide operative decisions.

Quantitative liver MR imaging with DWI sequence and Normalized ADC in diagnosis and staging of hepatitis C virus liver fibrosis and cirrhosis, a comparative study with transient elastography (Fibroscan) in egyptian patients

Abstract Purpose To evaluate the diagnostic efficacy of quantitative liver MR imaging using diffusion-weighted imaging (DWI) and normalized apparent diffusion coefficient (ADC) in diagnosis and staging of liver fibrosis and cirrhosis in egyptian patients with hepatitis C virus (HCV) infection and compare the results with transient elastography (FibroScan). Materials and Methods Twenty-five patients known to have hepatitis C virus were enrolled after fulfilling inclusion and exclusion criteria.. Quantification of liver, spleen and muscle ADC values was done using MRI DWI sequences using 4 different b-values (0, 200, 400, 800). Normalized ADC was calculated as the ratio of liver ADC to spleen ADC.. Post processing was performed using 3D synapse ADC viewer Tool. Results Liver ADC failed to distinguish different stages of fibrosis, except between stages 2 and 3 (p = 0.016). Normalized liver ADC distinguished between individual groups of fibrosis , with significant differences between mild stages (stage 0/1) and sever stages of fibrosis (stages 3) and between stages 0/1 and cirrhosis (stage 4). There were significant differences between stages 0–2 and 3–4 using normalized liver ADC. There was a statistically significant moderate correlation between fibrosis stage and normalized liver ADC (r = −0.403; p = 0.009). ROC analysis revealed higher performance using normalized liver ADC compared with liver ADC, with higher AUC, sensitivity, and specificity for detection of cirrhosis (stage 0 vs 4 and stages 0–3 vs 4), moderate-to-advanced fibrosis (stages 2–4), and advanced fibrosis and cirrhosis (stages 3–4), reaching significance for all comparisons except for diagnosis of stage 4 (cirrhosis). Conclusion Our results suggest that normalizing liver ADC with spleen ADC improves diagnostic accuracy for detection of liver fibrosis and cirrhosis in egyptian population when using breath-hold diffusion-weighted imaging.

Analysis of 7-tesla diffusion-weighted imaging in the prediction of pituitary macroadenoma consistency.

Endoscopic surgery is an effective treatment strategy for pituitary adenomas; however, intrinsic tumor properties such as tumor consistency can challenge or preclude gross-total resection. Preoperative characterization of tumor consistency may help to guide the surgical approach and to predict the extent of resection that is possible. Advanced radiological modalities such as 7T diffusion-weighted imaging (DWI) may be useful in probing biological tissue properties of pituitary adenomas. The objective of the present study was to examine 7T DWI as a novel method of measuring the consistency of pituitary adenomas. Thirteen patients with pituitary macroadenomas underwent 7T MRI, including a DWI image acquisition. Tumor apparent diffusion coefficient (ADC) was normalized to the adjacent temporal gray matter ADC. All patients underwent resection, and a single neurosurgeon blinded to ADC values rated tumor firmness from 1 (least firm) to 5 (most firm) using objective criteria. The tumor specimens were evaluated histopathologically for cellularity, collagen content, and vascularity by a neuropathologist who was also blinded to ADC values. The tumor ADC was correlated with intraoperative consistency rating, histopathology, and extent of resection. Receiver operating characteristic (ROC) curve analyses were performed to identify thresholds to predict tumor consistency. Corrected ADC values were significantly correlated with both tumor firmness (r = -0.60, p = 0.029) and the extent of trichrome staining (r = -0.72, p = 0.009) such that greater ADC values were associated with both decreased tumor firmness and decreased collagen staining. Correlations between ADC values and tumor vascularity were not significant (r = -0.09, p = 0.78). Corrected ADC values in totally resected tumors (1.54) were greater than those in subtotally resected tumors (0.85) (p = 0.02), and ADC values were greater with moderate tumor cellularity (1.51) than with high tumor cellularity (0.8) (p = 0.035). There was a trend-level association for partial resections to exhibit greater tumor firmness rating (3 vs 1.7; p = 0.051). Finally, the degree of trichrome staining positively correlated with tumor firmness (r = 0.60, p = 0.04). The optimal threshold for predicting intraoperative consistency rating was an ADC ratio of 0.87 (sensitivity 80%, specificity 100%, area under the curve [AUC] 0.90; p = 0.043). The optimal cutoff for distinguishing the extent of resection was 1.19 (sensitivity 85.7%, specificity 83.3% AUC 0.833; p = 0.046). The authors' results suggest that a high-resolution ADC of pituitary adenomas is a sensitive measure of tumor consistency. 7T DWI may hold clinical value in the preoperative workup and surgical management of patients with pituitary macroadenomas.

Biparametric versus multiparametric magnetic resonance imaging of the prostate: detection of clinically significant cancer in a perfect match group.

BackgroundBiparametric (bp) magnetic resonance imaging (MRI) could be an alternative MRI for the detection of the clinically significant prostate cancer (csPCa).PurposeTo compare the accuracies of prostate cancer detection and localization between prebiopsy bpMRI and postbiopsy multiparametric MRI (mpMRI) taken on different days, using radical prostatectomy specimens as the reference standards.Material and methodsData of 41 total consecutive patients who underwent the following examinations and procedures between September 2015 and March 2017 were collected: (1) magnetic resonance– and/or ultrasonography-guided biopsy after bpMRI; (2) postbiopsy mpMRI; and (3) radical prostatectomy with csPCa. Two radiologists scored suspected lesions on bpMRI and mpMRI independently using Prostate Imaging Reporting and Data System version 2. The diagnostic accuracy of detecting csPCa and the Dice similarity coefficient were obtained. Apparent diffusion coefficient (ADC) ratios were also obtained for quantitative comparison between bpMRI and mpMRI.ResultsDiagnostic accuracies on bpMRI and mpMRI were 0.83 and 0.82 for reader 1; 0.80 and 0.82 for reader 2. There are no significantly different values of diagnostic sensitivities or specificities between the readers or between MRI protocols. Intra-observer Dice similarity coefficient was significantly lower in reader 2, compared to that in reader 1 between the two MRI protocols. The range of mean ADC ratio was 0.281–0.635. There was no statistically significant difference in the ADC ratio between bpMRI and mpMRI.ConclusionsDiagnostic performance of bpMRI without dynamic contrast enhancement MRI is not significantly different from mpMRI with dynamic contrast enhancement MRI in the detection of csPCa.

Role of Diffusion Weighted Imaging in Characterization of Intracranial Rim Enhancing Lesions

Introduction: The differentiation of rim enhancing abscess from high grade necrotic lesions is difficult in conventional imaging. Our purpose was to assess the role of diffusion weighted imaging of intracranial rim enhancing lesions to differentiate the etiologies.&#x0D; Methods: Fifty one patients, 32 male and 19 female with mean age of 48.47 years and with rim enhancing intracranial lesions in magnetic resonance imaging, who underwent surgery from January 2012 to December 2012, were studied for different characteristics of the lesions in DWI and pathologically correlated the observed findings.&#x0D; Results: Out of 58 rim enhancing lesions 21 were primary brain tumor, 18 abscess, 14 metastasis and 5 neurocysticercosis. Twenty lesions had restricted diffusion in center, 22 lesions had thin smooth enhancing rim and 23 lesions were with low T2 complete rim. Diffusion restriction at non enhancing center of the lesion and thin smooth enhancing rim have sensitivity and specificity of 88.89% and 90.24% (p &lt;0.0001) for brain abscess and 83.33% and 80.49% (p &lt;0.0001) for other lesions. ADC ratio of center to that of normal white matter showed sensitivity and specificity of 88.9% and 90% respectively (p &lt;0.0001) at cut off point of 1.09. Lesions with thin smooth rim enhancement with diffusion restriction in nonenhancing center are 100% specific for brain abscess.&#x0D; Conclusions: On studying the different MRI characteristics of rim enhancing lesions, combining enhancement characteristic with DWI is more helpful in coming to the proper diagnosis.

İntratümöral Ve Peritümöral ADC(Apperent Diffusion Coefficient) Değerlerinin Pediatrik Beyin Tümörlerinin Tanısında Önemi Var Mıdır?

INTRODUCTION: The motion of water particles within biological tissues, which is called random Brownian motion, is detected at the microscopic level by Diffusion-Weighted Imaging (DWI) sequence of Magnetic Resonance Image technique. The Apparent Diffusion Coefficient (ADC) calculated on DWI has been used for tumor diagnosis and grading. The purpose of this study was to evaluate of ADC values in the differential diagnosis of supratentorial and infratentorial pediatric brain tumors and to reveal the difference of peritumoral ADC measurements of pediatric patients from adult patients. METHODS: All of the 56 pediatric patients included in this retrospective study had lesions &gt;1 cm in diameter on magnetic resonance image and all of the diagnosies were confirmed by histopathology. Intratumoral and peritumoral ADC values and ratios were measured in diffusion weighted Magnetic Resonance Image. RESULTS: The 58.9% (n=33) of these tumors were supratentorial and 41.1% (n=23) were infratentorial. ADC values and ADC ratios were significantly lower in high-grade tumors than low-grade tumors (p&lt;0.05). Peritumoral ADC values in high-grade tumors were lower than low grade tumors (p&lt;0.05). The cut-off value of the ADC ratio between these two groups was 1 and the ADC cut-off value was 1.1*10-3 mm2/s. DISCUSSION AND CONCLUSION: In the differentiation of low and high-grade pediatric brain tumors, cut-off values of 1.1*10_3mm2/s for ADC Value and 1.0 for ADC Ratio may be useful. Although, peritumoral ADC values differ in children compared to the adult group, both intratumoral and peritumoral ADC values can help for grading pediatric brain tumors.

Role of diffusion-weighted imaging in evaluation of intracranial infections

Objective: The objective is to evaluate the role of diffusion weighted imaging (DWI) in evaluation of intracranial infections. Methods: The present study was conducted in the Department of Radiology, Jawaharlal Nehru Medical College, Sawangi, Maharashtra, India. Participants after understanding the study protocol and procedure were asked to give their written consent for the study. DWI was performed on 24 patients having ring-enhancing lesions on their post-contrast brain magnetic resonance imaging scans with infective etiology. Commonly found lesions were tuberculomas, cysticercosis, pyogenic abscess, and fungal infections. Correlation of all these findings was done with histopathology obtained in all these patients. DWI and mean apparent diffusion coefficient (ADC) value were calculated. Results: Tuberculomas showed heterogeneous areas of restricted diffusion on DWI were as pyogenic abscess showed homogenous restricted diffusion, the mean ADC values from of these lesions were 0.74 × 10−3 and 0.5 × 10−3 mm2/s, respectively. Fungal abscesses were also ring enhancing. They had restricted diffusion in the central nonenhancing portions. Mean ADC for all fungal lesions was 0.33 ± 0.06 × 10−3 mm2/s, with an average ADC ratio of 0.43. However, there was no significant difference between ADC values of pyogenic abscess and fungal abscess. The vesicular cysts of NCC showed ring enhancement but no significant restriction on DWI, the ADC values from the vesicular cysticercus cysts core measured (1.66 ± 0.29) ×10 − 3 mm2/s, which was highest among the infective intracranial infection. Conclusion: DWI is noninvasive method with high sensitivity and specificity which can help in differentiation of infective ring-enhancing lesions. Fungal cerebral abscesses may have central restricted diffusion similar to that of bacterial abscesses but with histologic features of acute or chronic inflammation and necrosis rather than suppuration. Altered water diffusion in these lesions likely reflects highly proteinaceous fluid and cellular infiltration. The tuberculoma and NCC lesions showed heterogeneous and no restriction on DWI respectively with significant change in the ADC values which helped in differentiating these lesions. This modality should be read in conjunction with conventional imaging.

DWI and PRECISE criteria in men on active surveillance for prostate cancer: A multicentre preliminary experience of different ADC calculations

PurposeThe PRECISE score estimates the likelihood of radiological progression in patients on active surveillance (AS) for prostate cancer (PCa) with serial multiparametric magnetic resonance imaging (mpMRI). A PRECISE score of 1 or 2 denotes radiological regression, PRECISE 3 indicates stability and PRECISE 4 or 5 implies progression.We evaluated the inter-reader reproducibility of different apparent diffusion coefficient (ADC) calculations and their relationship to the PRECISE score. Material and methodsBaseline and follow-up scans (on the same MR systems) of 30 patients with visible lesions from two different institutions (University College London and Sapienza University of Rome) were analysed by two radiologists (one from each site). The PRECISE score was initially assessed in consensus. At least six weeks later, to reduce the likelihood of being influenced by the consensus PRECISE reading, each radiologist independently calculated ADC for the following: lesion, non-cancerous tissue and urine in the bladder. Normalised ADC ratios were calculated with respect to normal prostatic tissue (npADC) and urine. Spearman's correlation (ρ), intraclass correlation coefficients (ICC), differences in ADC and ROC curves were computed. ResultsInterobserver reproducibility was very good (ρ > 0.8; ICC > 0.90). Lesion ADC (0.91 vs 0.73 × 10−3 mm2/s; p=0.025) and npADC ratio (0.68 vs 0.53; p=0.012) at follow-up mpMRI were different between patients with radiological regression or stability vs progression. Cut-offs of 0.77 × 10−3 mm2/s (lesion ADC) and 0.59 (npADC ratio) could differentiate the two groups (area under the curve: 0.74 and 0.77, respectively). ConclusionThe ADC, npADC ratio and the PRECISE score should be recorded for MRI-based AS.

The Role of Diffusion-weighted Imaging in Patients with Gastric Wall Thickening

Gastric cancer is the second leading cause of cancer death worldwide. In the benign and malign gastric pathologies, we measured the Apparent Diffusion Coefficient (ADC) value from the thickened section of the stomach wall. We assessed the diagnostic value of ADC and we wanted to see whether this value could be used to diagnose gastric pathologies. This study has a prospective study design. A total of 90 patients, 27 with malign gastric pathologies 63 with benign gastric pathologies with Gastric Wall (GW) thickening in multidector CT, were evaluated by T2 weighted axial MR imaging and Diffusion-Weighted Imaging (DWI). Measurements were made both from the thickened wall and from the normal GW. Also, a new method called GW/spine ADC ratio was performed in image analysis. The value found after ADC measurement from the GW was proportioned to the spinal cord ADC value in the same section. The ADC values measured from the pathological wall in patients with gastric malignancy (1.115 ± 0.156 x10-3 mm2/s) were significantly lower than the healthy wall measurements (1.621 ± 0.292 × 10-3 mm2/s) and benign gastric diseases (1.790± 0.359 x10-3 mm2/s). GW/spine ADC ratio was also lower in gastric malignancy group. ADC measurement in DWI can be used to distinguish between benign and malign gastric pathologies.

Quantification of Functional MR Predicts Early Response in Post-doxorubicin Drug-Eluting Beads Chemoembolization for Hepatocellular Carcinoma.

The purpose of this study was to assess the value of functional MRI (fMRI) of post-doxorubicin drug-eluting beads transcatheter arterial chemoembolization (DEB-TACE) for hepatocellular carcinoma (HCC) as an early imaging biomarker of response to therapy. This prospective analysis included 21 consecutive patients undergoing fMRI before and after DEB-TACE at a single medical center from January 2013 to December 2014. Functional MRI, including relative changes in apparent diffusion coefficient (ADC) and choline levels measured at hydrogen-1 magnetic resonance spectroscopy (MRS) of treated lesions, was recorded at baseline before DEB-TACE, and at 1, 2, and 4weeks after DEB-TACE therapy. Assessment of tumor response was based on dynamic contrast-enhanced computer tomography imaging response according to modified response evaluation criteria in solid tumors. At post-therapy, 76% (n = 16) of patients demonstrated objective tumor response, 10% (n = 2) had stable disease, and 3 (14%) had progressive disease. Stable disease and progressive disease were designated as non-response. At week 2, the mean change in ADC value of responsive tumors was 0.35 ± 0.24mm2/s, which was greater than that of non-response tumors (mean 0.01 ± 0.13 × 10-3mm2/s) (P = 0.006). Significant differences were found in mean choline/water ratio between responsive (7.8 ± 4.9 × 10-3) and non-responsive (17.2 ± 4.9 × 10-3) tumors (P = 0.005). Composite scores of choline/water ratio and relative change of ADC showed significantly better diagnostic accuracy in non-responsive tumors than responsive tumors (area under the curve = 1.0; P < 0.001). Combined DWI and MRS may be used as an early imaging biomarker of therapy response in HCC patients after chemoembolization therapy.

Histogram analysis of apparent diffusion coefficient and fluid-attenuated inversion recovery in discriminating between enhancing and nonenhancing lesions in multiple sclerosis

PurposeThis study evaluates the diagnostic performance of apparent diffusion coefficient (ADC) and T2 fluid-attenuation inversion recovery (T2 FLAIR) in discriminating between new white matter (WM) enhancing lesions (ELs) and non-enhancing lesions (NELs) in multiple sclerosis (MS) patients. MethodsThirty MS patients with a new solitary WM lesion on brain MRI were analyzed. A region-of-interest was drawn on all lesions and the contralateral normal-appearing WM (NAWM) on T2 FLAIR and ADC maps. Normalized ratios of T2 FLAIR and ADC were calculated by dividing lesion value by the contralateral NAWM. Histogram analysis was performed on the T2 FLAIR, ADC values, and their normalized ratios. Mann-Whitney U test was used to compare histogram parameters and receiver operating characteristic (ROC) analysis determined the area under the curve (AUC). ResultsT2 FLAIR histogram parameters were not significantly different between ELs and NELs. Several EL ADC histogram parameters, including maximum and mean, were significantly higher than NELs (p = 0.006 to p = 0.031). There was a trend toward significantly higher maximum ADC in ELs after adjusting for multiple comparisons (p = 0.054). The standard deviation of T2 FLAIR (AUC 0.70), maximum ADC (AUC 0.79), and normalized maximum ADC ratio (AUC 0.75) were among histogram parameters with the highest diagnostic performance. A maximum ADC cutoff of 1274 × 10−6 mm2/s provided a 0.86 sensitivity and 0.75 specificity. ConclusionIn patients with contraindications to gadolinium or concerns with gadolinium brain deposition, consideration may be given to ADC and T2 FLAIR as potential noncontrast methods for the evaluation of active MS lesions.

Gd-EOB-DTPA MRI Imaging and Apoptosis Research in Orthotopic Rats Model of Hepatocellular Carcinoma after Stereotactic Radiotherapy

To investigate the characteristics of Gd-EOB-DTPA MRI imaging tumor cell apoptosis and the correlation between them in orthotopic rats model of hepatocellular carcinoma after stereotactic radiotherapy. Forty healthy male Sprague-Dawley rats were randomly divided into model group (n=40) and control group (n=20). When the tumor diameter was ≥1.0cm, the rats in the experimental group underwent single stereotactic radiotherapy with a dose of 15Gy. 40 rats after radiotherapy were randomly divided into 4 groups, 10 in each group. The control group was randomly divided into 4 groups of 5 each, and the above group was added. MR rats were routinely scanned and DWI scans were performed on the 1st, 7th, 14th, and 21st day after radiotherapy. The region of interest (ROI) ADC value and signal intensity (SI) of the tumor and normal life after radiotherapy were measured, and the ratio of ADC to SI (tumor/liver) was calculated. After the end of the scan, the animals were sacrificed, and the liver cell tumor specimens were subjected to DNA nick end labeling (TUNEL) to determine the apoptosis of the tumor cells, and the apoptotic index (apoptotic cells/tumor cells) was calculated. Two independent sample t-tests were used to compare the apoptotic index and ADC ratio between the radiotherapy group and the control group. Comparison of apoptotic index and ADC ratio between the radiotherapy groups was analyzed by one-way analysis of variance; the correlation between the two was performed using the Pearson test. The ADC and SI ratios were statistically significant at 7 days, 14 days and 21 days after radiotherapy (P<0.01=, there was no significant difference at 1 day after radiotherapy (P>0.05). 1 day, 7 days, 14 days, The apoptotic index of the 21-day radiotherapy group was significantly different from that of the control group (P<0.05=. The ADC and SI ratios were positively correlated with the apoptotic index (AI) (P<0.05). The imaging characteristics of Gd-EOB-DTPA MRI can reflect the dynamic changes of apoptosis at different time points after stereotactic radiotherapy in rat liver cancer.

Three-dimensional reversed fast imaging with steady-state precession diffusion-weighted imaging for the detection of middle ear cholesteatoma

To determine the usefulness of three-dimensional reversed fast imaging with steady-state precession diffusion-weighted imaging (3D-PSIF DWI) for the detection of middle ear cholesteatoma. The study population consisted of 81 patients who underwent 3D-PSIF-DWI at 3 T. They included cholesteatoma in 73 cases, otitis media in five, and cholesterol granuloma in three. Two observers independently performed qualitative evaluations for the detection of cholesteatoma and measured apparent diffusion coefficient (ADC) values and ADC ratios of the lesions. Kappa (κ) statistics, the intraclass correlation coefficient (ICC), the independent t-test, and receiver operating characteristic (ROC) analysis were used for statistical analysis. Pair-wise comparison of the ROC curves was performed using the area under the ROC curve (AUC). Interobserver agreement and ICC for the qualitative and quantitative evaluations were excellent (κ=0.92 and ICC=0.90-0.92, respectively). The ADC value and the ADC ratio were significantly lower for cholesteatoma than non-cholesteatoma lesions (p<0.0001). In <5 mm cholesteatoma group, the diagnostic performance of the ADC value (AUC=0.97) and the ADC ratio (AUC=1) was significantly superior to qualitative 3D-PSIF-DWI (AUC=0.76; p=0.0001 and <0.0001, respectively). For ≥5 mm cholesteatoma group, there were no significant differences in diagnostic performance among the three parameters. 3D-PSIF-DWI sequence is useful for the detection of middle ear cholesteatomas, especially <5 mm lesions.

Associations Between Diffusion Dynamics and Functional Outcome in Acute and Early Subacute Ischemic Stroke.

The current study aimed to investigate the associations between diffusion dynamics of ischemic lesions and clinical functional outcome of acute and early subacute stroke. A total of 80 patients with first ever infarcts in the territory of the middle cerebral artery underwent multi-b-values diffusion-weighted imaging and diffusion kurtosis imaging. Multiple diffusion parameters were generated in postprocessing using different diffusion models. Long-term functional outcome was evaluated with modified Rankin scale (mRS) at 6 months post-stroke. Good functional outcome was defined as mRS score ≤ 2 and poor functional outcome was defined as mRS score ≥ 3. Univariate analysis was used to compare the diffusion parameters and clinical features between patients with poor and good functional outcome. Significant parameters were further analyzed for correlations with functional outcome using partial correlation. In univariate analyses, standard-b-values apparent diffusion coefficient (ADCst) ratio and fractional anisotropy (FA) ratio of acute stroke, ADCst ratio and mean kurtosis (MK) ratio of early subacute stroke were statistically different between patients with poor outcome and good outcome (P < 0.05). When the potential confounding factor of lesion volume was controlled, only FA ratio of acute stroke, ADCst ratio and MK ratio of early subacute stroke remained correlated with the functional outcome (P < 0.05). Diffusion dynamics are correlated with the clinical functional outcome of ischemic stroke. This correlation is independent of the effect of lesion volume and is specific to the time period between symptom onset and imaging. More effort is needed to further investigate the predictive value of diffusion-weighted imaging.

Peritumoral ADC values in breast cancer: region of interest selection, associations with hyaluronan intensity, and prognostic significance

ObjectivesWe aimed to evaluate the differences in peritumoral apparent diffusion coefficient (ADC) values by four different ROI selection methods and to validate the optimal method. Furthermore, we aimed to evaluate if the peritumor-tumor ADC ratios are correlated with axillary lymph node positivity and hyaluronan accumulation.MethodsAltogether, 22 breast cancer patients underwent 3.0-T breast MRI, histopathological evaluation, and hyaluronan assay. Paired t and Friedman tests were used to compare minimum, mean, and maximum values of tumoral and peritumoral ADC by four methods: (M1) band ROI, (M2) whole tumor surrounding ROI, (M3) clockwise multiple ROI, and (M4) visual assessment of ROI selection. Subsequently, peritumor/tumor ADC ratios were compared with hyaluronan levels and axillary lymph node status by the Mann-Whitney U test.ResultsNo statistically significant differences were found among the four ROI selection methods regarding minimum, mean, or maximum values of tumoral and peritumoral ADC. Visual assessment ROI measurements represented the less time-consuming evaluation method for the peritumoral area, and with sufficient accuracy. Peritumor/tumor ADC ratios obtained by all methods except the clockwise ROI (M3) showed a positive correlation with hyaluronan content (M1, p = 0.004; M2, p = 0.012; M3, p = 0.20; M4, p = 0.025) and lymph node metastasis (M1, p = 0.001; M2, p = 0.007; M3, p = 0.22; M4, p = 0.015), which are established factors for unfavorable prognosis.ConclusionsOur results suggest that the peritumor/tumor ADC ratio could be a readily applicable imaging index associated with axillary lymph node metastasis and extensive hyaluronan accumulation. It could be related to the biological aggressiveness of breast cancer and therefore might serve as an additional prognostic factor.Key Points• Out of four different ROI selection methods for peritumoral ADC evaluation, measurements based on visual assessment provided sufficient accuracy and were the less time-consuming method.• The peritumor/tumor ADC ratio can provide an easily applicable supplementary imaging index for breast cancer assessment.• A higher peritumor/tumor ADC ratio was associated with axillary lymph node metastasis and extensive hyaluronan accumulation and might serve as an additional prognostic factor.

Dynamic contrast-enhanced and diffusion-weighted MRI of invasive breast cancer for the prediction of sentinel lymph node status.

Although sentinel lymph node biopsy (SLNB) is the current standard for identifying lymph metastasis in breast cancer patients, there are complications of SLNB. To evaluate preoperative dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and diffusion-weighted imaging (DWI) of invasive breast cancer for predicting sentinel lymph node metastasis. Retrospective. In all, 309 patients who underwent clinically node-negative invasive breast cancer surgery FIELD STRENGTH/SEQUENCE: 3.0T, DCE-MRI, DWI. We collected clinicopathologic variables (age, histologic and nuclear grade, extensive intraductal carcinoma component, lymphovascular invasion, and immunohistochemical profiles) and preoperative MRI features (tumor size, background parenchymal enhancement, internal enhancement, adjacent vessel sign, whole-breast vascularity, initial enhancement pattern, kinetic curve types, quantitative kinetic parameters, tumoral apparent diffusion coefficient [ADC], peritumoral maximal ADC, and peritumoral-tumoral ADC ratio). Multivariate logistic regressions were performed to determine independent variables associated with SLN metastasis, and the area under the receiver operating characteristic curve (AUC) was analyzed for those variables. 41 (13.3%) of the patients showed SLN metastasis. With MRI, tumor size (odds ratio [OR], 1.11; 95% confidence interval [CI], 1.06-1.17), heterogeneous (OR, 5.33; 95% CI, 1.71-16.58), and rim (OR, 15.54; 95% CI, 2.12-113.72) enhancement and peritumoral-tumoral ADC ratio (OR, 72.79; 95% CI, 7.15-740.82) were independently associated with SLN metastasis. Clinicopathologic variables independently associated with SLN metastasis included age (OR, 0.96; 95% CI, 0.92-0.99) and CD31 (OR, 2.90; 95% CI, 1.04-8.92). The area under the curve (AUC) of MRI features (0.80; 95% CI, 0.73-0.87) was significantly higher than for clinicopathologic variables (0.68; 95% CI, 0.60-0.77; P = 0.048) and was barely below statistical significance for combined MRI features with clinicopathologic variables (0.84; 95% CI 0.78-0.90, P = 0.057). Preoperative internal enhancement on DCE-MRI and peritumoral-tumoral ADC ratio on DWI might be useful for predicting SLN metastasis in patients with invasive breast cancer. 3 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2020;51:615-626.

EFFECTIVENESS OF DIFFUSION WEIGHTED MRI DERIVED METRICS IN DIFFERENTIATION OF PEDIATRIC POSTERIOR FOSSA TUMORS

Background: The value of diffusion weighted imaging (DWI) in differentiation of pediatric posterior fossa tumors (PFTs)has been established previously, however most studies were limited only to the most common types of PFTs and their results were contradictory.. Aim of work: The aim of this study was to investigate the effectiveness of DWI in differentiation of PFTs taking care to include the less frequent types, and to clarify previously reported debatable findings. Patients and methods: We retrospectively analyzed 13 embryonal tumors (EMBTs), 4 ependymomas (EPNs),8 low grade gliomas (LGGs),2 mixed neuronal glial tumors (MNGTs), and 5 diffuse intrinsic pontine gliomas (DIPGs) . For all tumors, absolutemean ADC of the non necrotic enhancing portions of the tumor and ADC ratios of the solid enhancing region of the tumor to the ADC of normal appearing cerebellum were generated. The ADC metrics of the various groups (designated according to histological subtype and WHO grade) were compared using the kruskal – wallis and student-ttests. Receiver operating characteristic (ROC) curve analysis was used to generate cutoff absolute ADC values and ADC ratios for differentiation of different types of PFTs Results: Mean ADC values and ADC ratios were significantly lower in high than in low grade tumors (P 1.108× 10−3 (100% sensitivity and 92.3% specificity)but not with mean ADC values and from LGGs using a cutoff mean ADC value of ≤ 1.333 (100% sensitivity and specificity). No statistically significant difference (P >0.05) was seen between the mean ADC values of MNGTs (1.5+/-0.02) and LGGs (1.71+/-0.13) with wide overlap in their range of ADC values and ratios.Conclusion: Apart from a few exceptions, absolute ADC values and ratios go a long way in enabling pre-operative differentiation of different types of PFTs.

Serebellar Tümörleri Birbirinden Ayırt Etmek İçin Yeni Bir Yöntem: Algoritmik Yaklaşım

Objective: To evaluate the MR imaging findings of the cerebellar tumors (CT) in adults and to make an algorithm to discriminate these tumors from each other. Materials and Methods: A dult patients with CT who were treated surgically were included. Brain MRs and patient records were evaluated for pathological diagnosis, imaging findings and Ki-67 labeling index. The apparent diffusion coefficient (ADC) values of the tumors and centrum semiovale (CS) and the ratio of each other were noted. Kruskal-Wallis test was used for comparison. Results: 100 adults (45 women, 55 men with a mean age of 46.6 ± 15.6 years) with pathologically proven CT were included. Tumors were divided into five groups as: a. primitive neuro-ectodermal tumor (PNET) + medulloblastoma ( MB), b. grade 3+4 gliomas, c. grade 1+2 gliomas, d. metastasis (MET) and e. lymphoma. The ratio of the mean ADC (x10 -3 mm 2 /s) of the tumor to those of CS was 1.21 ± 0.22, 1.38 ± 0.93, 1.98 ± 0.69, 1.48 ± 0.45 and 1.25 ± 0.11 for PNET&MBs, grade 3+4 gliomas, grade 1+2 gliomas, METs and lymphomas, respectively. Significant difference was detected between grade 1+2 gliomas and PNET&MB ( P =0.018), MET ( P =0.004) and lymphoma ( P =0.002). Conclusion: CT in adults might be differentiated from each other by using some MR imaging clues and patient characteristics.

Apparent Diffusion Coefficient (ADC) Ratio Versus Conventional ADC for Detecting Clinically Significant Prostate Cancer With 3-T MRI.

OBJECTIVE. The purpose of this study is to evaluate the performance of the apparent diffusion coefficient ratio (ADCratio; the ADC of the suspected prostate cancer [PCa] focus on MRI divided by the ADC in a noncancerous reference area) with that of conventional ADC for detection of high-grade PCa (Gleason score [GS] ≥ 3 + 4) versus low-grade PCa (GS = 3 + 3) with whole-mount (WM) histopathologic analysis used as a reference. MATERIALS AND METHODS. The cohort of this retrospective study included 218 men with 240 unilateral PCa lesions assessed by both 3-T multiparametric MRI and whole-mount histopathologic analysis. ROIs were placed on individual lesions verified by WM histopathologic analysis, to calculate the mean ADC (ADCtumor_mean) and lowest ADC within each lesion (ADCtumor_min), and within non-tumor-containing regions of the same tumor zone but on the contralateral side (ADCbenign), to calculate the background ADC. The ADCratio_mean (the ADCtumor_mean divided by the ADCbenign) was calculated. The performance of individual ADCtumor and ADCratio_mean values in discriminating PCa with a GS of 3 + 3 from PCa with a GS of 3 + 4 or greater was assessed using the AUC value. RESULTS. The ADCratio_mean had a higher AUC value for discriminating PCa lesions with a GS of 3 + 3 from those with a GS of 3 + 4 or greater (the AUC value increased from 0.70 using the ADCtumor_mean and 0.67 using the ADCtumor_min [the minimum ADC of the PCa lesion] to 0.80 for the ADCratio_mean and 0.72 for the ADCratio_min [the ADCtumor_min divided by the ADCbenign]; p = 0.043). When stratified by PCa zonal location, the ADCratio_mean had significantly more robust accuracy in the transition zone (the AUC value increased from 0.63 for ADCtumor_mean to 0.87 for ADCratio_mean; p = 0.019) compared with the peripheral zone (the AUC value increased from 0.74 for ADCtumor_mean to 0.78 for ADCratio_mean; p = 0.44). When analyzed on the basis of endorectal coil use, the ADCratio_mean performed nonsignificantly better in both the endorectal coil and non-endorectal coil subcohorts, although it performed better in the former. CONCLUSION. As an intrapatient-normalized diagnostic tool, the ADC ratio provided the best AUC value for discrimination of low-grade from high-grade PCa on 3-T MRI.

Multiparametric MR imaging to assess response following neoadjuvant systemic treatment in various breast cancer subtypes: Comparison between different definitions of pathologic complete response

ObjectivesTo validate the performance of multiparametric magnetic resonance (MR) imaging to assess pathologic response to neoadjuvant systemic therapy (NST) in various breast cancer subtypes considering two definitions of pCR: absence of any residual invasive cancer or DCIS (ypT0) and absence of invasive tumour cells (ypT0/is). MethodsInstitutional review board–approved retrospective study, with waiver of the need to obtain informed consent. From January 2015 to June 2017, 81 women with 82 breast cancers undergoing NST were included. Eighteen lesions (22%) were immunohistochemically HER2-positive, 12 (15%) triple negative (TN), 42 (51%) luminal B-like and 10 (12%) luminal B-like/HER2-positive. Breast MR imaging was performed before and after NST. A comparative analysis considering pCR as ypT0 and ypT0/is was carried out. Performance of univariate and multivariate models to potentially predict pathologic response were evaluated. ResultsypT0 was attained in 23% (19/82) of cases and ypT0/is in 33% (27/82) of cases. In both scenarios, HER2-positive subtype achieved the best response, 53% and 48%, respectively. A significant relationship was found between late enhancement and pathologic response (p < 0.001) regardless of pCR definition. In the ypT0 scenario, mean ADC ratio in the pCR subgroup was significantly higher than that in the non-pCR subgroup (p = 0.021) but no significant relationship was noted in ypT0/is. A multivariate model including MR late enhancement, ADC ratio and tumor subtype identified pathologic response with 86% and 84% accuracy when ypT0 and ypT0/is were considered, respectively. ConclusionMR imaging late enhancement and ADC ratio along with breast cancer IHC subtype identify pathologic response following NST with high accuracy, achieving the highest NPV in TN and HER2-positive tumors and the highest PPV in luminal B-like subtypes, regardless of the definition of pCR as ypT0 or ypT0/is. In light of these findings and given that residual DCIS does not have an impact on survival rates, ypT0/is seems to be the preferable definition of pCR.