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Improving the detection rates of prostate cancer (PCa) and avoiding unnecessary prostate biopsies in men with prostate‐specific antigen (PSA) levels within the gray zone require urgent attention. In this context, rapid advances in MR technology in recent years may offer a promising possibility. A systematic review to evaluate the applications of magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS) in detecting PCa and clinically significant PCa (csPCa) in men with PSA levels within the gray zone. The study type is defined as systematic review. In July 2022, out of 229 studies identified by the database search and from other sources, 23 articles related to the selected topic of interest were included in this review. No field strength or sequence restrictions. The data including the study population, study characteristics, as well as basic MRI characteristics, from the final studies included in this review, were extracted independently by two reviewers. The major results of the original study were summarized and no additional statistical analysis was performed. Among the 23 studies included in this review, 17 focused on the applications of MRS and MRI for the prebiopsy diagnosis of PCa. Nine of these 17 articles used Prostate Imaging Reporting and Data System (PI‐RADS) score to interpret MRI results, thereby confirming the practicality of the PI‐RADS score in predicting PCa and csPCa. The remaining six articles evaluated the applications of MRI and MRS in guiding prostate biopsy. Although there was a variation in the biopsy modalities used in these studies, both MRI‐ and MRS‐guided prostate biopsies were observed to improve the detection rates of PCa and csPCa in patients with PSA levels within the gray zone. MRS and MRI showed good performance in the detection of PCa and csPCa before biopsy. In addition, MRS‐ or MRI‐guided prostate‐targeted biopsies were able to improve the detection rates of PCa and csPCa. Evidence Level: 3 Technical Efficacy: Stage 2 [ABSTRACT FROM AUTHOR]

Background: Diffusion‐weighted imaging (DWI) is an important method for clinically significant prostate cancer (csPCa) diagnosis; however, the Prostate Imaging‐Reporting and Data System (PI‐RADS) requires the subjective assessment of "markedly hypointense or not" on apparent diffusion coefficient (ADC) map. We hypothesize that weighted diffusion subtraction (WDS) images, created by weighted subtraction of high and low b‐value DWIs, might better show areas of ADC values below a set threshold, thus decreasing the subjectivity of the assessment. Purpose: To evaluate the diagnostic ability of WDS for csPCa by comparing scores based on WDS images (DWI/WDS) with those based on PI‐RADS DWI (DWI/ADC). Study Type: Retrospective. Subjects: Eighty‐six PCa patients. Field Strength/Sequences: 3.0 T; DWI. Assessment: Four readers assessed the probability of csPCa in lesions (overall, in the peripheral zone [PZ] and transitional zone [TZ]) using 5‐point DWI/ADC and DWI/WDS scores. Prostatectomy specimens were the reference standard. ADC values and contrast between csPCa and normal prostate tissue on ADC maps and WDS images were calculated with reference to the pathological map. Statistical Tests: Diagnostic ability was evaluated by Jackknife alternative free‐response receiver‐operating characteristic curve. Figure of merit (FOM), sensitivity, and positive predictive value (PPV) between the DWI/ADC and DWI/WDS scores were compared using paired t‐test. Inter‐reader agreement was analyzed using κ statistics, and the significance probability was calculated using the Z statistic. Wilcoxon signed‐rank test was used to compare contrast between csPCa and normal prostate tissue on ADC maps and WDS images. A P value <0.05 was considered statistically significant. Results: FOM and sensitivity of the DWI/WDS scores were significantly better than those of the DWI/ADC scores overall, in the PZ and TZ (FOM: overall, 0.715 vs. 0.783; PZ, 0.756 vs. 0.815; TZ, 0.653 vs. 0.738. Sensitivity: overall, 0.512 vs. 0.607; PZ, 0.485 vs. 0.573; TZ, 0.636 vs. 0.761). For PPV, a statistically significant difference was observed overall (0.727 vs. 0.777). The κ value of DWI/WDS score was significantly higher than that of DWI/ADC score overall and in the PZ (overall, 0.614 vs. 0.792; PZ, 0.609 vs. 0.797). Contrast was significantly higher overall in the PZ and TZ in WDS images (median, 1.26, 1.19, and 1.61) than in ADC maps (0.46, 0.47, and 0.41). Data Conclusion: WDS images performed better than ADC maps in the diagnosis of csPCa and in inter‐reader agreement of the diagnosis. Level of Evidence: 4 Technical Efficacy Stage: 2 [ABSTRACT FROM AUTHOR]

Background: There appears to be less agreement in the identification of cancers in the transition zone (TZ), which is not as reliable as those in peripheral zone when using the Prostate Imaging Reporting and Data System (PI-RADS) version 2 (v2). In response to such shortcomings, the updated version 2.1 was introduced, which incorporated diffusion-weighted imaging (DWI) into category 2 and clarified lexicons.Purpose: To compare the diagnostic performance for the detection of clinically significant TZ prostate cancers (csPCa) and interreader agreement between PI-RADS v2.1 and v2.Study Type: Retrospective study.Population: In all, 142 patients, 201 TZ lesions.Field Strength/sequence: 3.0T; T2 -weighted image and DWI.Assessment: Lesions were scored by three independent readers using PI-RADS v2 and v2.1.Statistical Tests: The sensitivity and specificity at category ≥3 were compared between v2 and v2.1 using the generalized estimating equation model. Detection rates for csPCa of upgraded and downgraded lesions in the use of PI-RADS v2.1 from v2 were assessed. Interreader agreement was assessed using κ statistics.Results: PI-RADS v2.1 showed a higher sensitivity and specificity (94.5% and 60.9%) than v2 (91.8% and 56.3%) for category ≥3 lesions in the detection of csPCa, although not significantly. Of eight upgraded lesions from category 2 to 3 (2 + 1) with an incorporated DWI, 50% (4/8) were csPCa. This was significantly higher than category 2 lesions (4.4%; P = 0.003). No csPCa was detected among the 22.8% (46/201) downgraded lesions. There was a moderate interreader agreement for scores ≥3 (κ = 0.565) in v2.1, which was slightly higher than that for v2 (κ = 0.534), although not significantly.Data Conclusion: PI-RADS v2.1 provides moderate and comparable interreader agreement at category ≥3 than v2 in the TZ lesions. Upgraded lesions from category 2 to 3 demonstrated a higher detection rate of csPCa than category 2 lesions in v2.1.Level Of Evidence: 4 TECHNICAL EFFICACY STAGE: 2 J. Magn. Reson. Imaging 2020;52:577-586. [ABSTRACT FROM AUTHOR]

Background: In clinical practice arterial anatomy evaluation is often determined using computed tomographic angiography (CTA); the effect of enhanced MRI has been neglected.Purpose: To evaluate whether multiple arterial phase (MAP) images from patients who underwent differential subsampling with Cartesian ordering (DISCO) acquisition would improve the hepatic arterial display compared with single arterial phase (SAP) and CTA.Study Type: A prospective, randomized trial.Subjects: In all, 130 patients (mean age, 55.81 ± 9.43 years; range, 35-78 years) including 89 men and 41 women.Field Strength/sequence: 3.0T, DISCO, liver acquisition with volume acceleration-flexible (LAVA-Flex), CTA.Assessment: A simple randomization was conducted and the study was subdivided into study part I (DISCO vs. SAP) and study part II (DISCO vs. CTA). Ten hepatic arterial segments were independently evaluated by three readers in the axial plane and the quality of hepatic arterial display was assessed using a four-point scale.Statistical Tests: Kendall's W-test, χ2 test, Mann-Whitney U-test, and Kruskal-Wallis one-way analysis of variance (ANOVA) test.Results: Excellent interobserver agreement was obtained for hepatic arterial display (all Kendall's W values >0.80). For study part I, the mean arterial display scores for the common hepatic artery (CHA), proper hepatic artery (PHA), left hepatic artery (LHA), right hepatic artery (RHA), left gastric artery (LGA), and gastroduodenal artery (GDA) obtained with DISCO were higher than that obtained with SAP imaging (all P < 0.01). For study part II, comparable image quality for CHA (P = 0.798), PHA (P = 0.440), LHA (P = 0.211), RHA (P = 0.775) LGA (P = 0.468), and GDA (P = 0.801) was obtained with DISCO and CTA.Data Conclusion: The use of MAP acquisition with DISCO is superior to the use of SAP in hepatic arterial display and compares favorably with CTA; in the future, DISCO possibly can replace the latter ionization-related method to provide a more comprehensive evaluation of the liver arterial vessels.Level Of Evidence: 1 Technical Efficacy Stage: 1 J. Magn. Reson. Imaging 2020;51:1766-1776. [ABSTRACT FROM AUTHOR]

Background: Multiparametric MRI of the prostate has been shown to improve the risk stratification of men with an elevated prostate-specific antigen (PSA). However, long acquisition time, high cost, and inter-center/reader variability of a routine prostate multiparametric MRI limit its wider adoption.Purpose: To develop and validate nomograms based on unique rapid biparametric MRI (bpMRI) qualitative and quantitative derived variables for prediction of clinically significant cancer (SPCa).Study Type: Retrospective analyses of single (IMPROD, NCT01864135) and multiinstitution trials (MULTI-IMPROD, NCT02241122).Population: 161 and 338 prospectively enrolled men who completed the IMPROD and MULTI-IMPROD trials, respectively.Field Strength/sequence: IMPROD bpMRI: 3T/1.5T, T2 -weighted imaging, three separate diffusion-weighted imaging (DWI) acquisitions: 1) b-values 0, 100, 200, 300, 500 s/mm2 ; 2) b values 0, 1500 s/mm2 ; 3) values 0, 2000 s/mm2 .Assessment: The primary endpoint of the combined trial analysis was the diagnostic accuracy of the combination of IMPROD bpMRI and clinical variables for detection of SPCa.Statistical Tests: Logistic regression models were developed using IMPROD trial data and validated using MULTI-IMPROD trial data. The model's performance was expressed as the area under the curve (AUC) values for the detection of SPCa, defined as ISUP Gleason Grade Group ≥2.Results: A model incorporating clinical variables had an AUC (95% confidence interval) of 0.83 (0.77-0.89) and 0.80 (0.75-0.85) in the development and validation cohorts, respectively. The corresponding values for a model using IMPROD bpMRI findings were 0.93 (0.89-0.97), and 0.88 (0.84-0.92), respectively. Further addition of the quantitative DWI-based score did not improve AUC values (P < 0.05).Data Conclusion: A prediction model using qualitative IMPROD bpMRI findings demonstrated high accuracy for predicting SPCa in men with an elevated PSA. Online risk calculator: http://petiv.utu.fi/multiimprod/ Level of Evidence: 1 Technical Efficacy Stage: 2 J. Magn. Reson. Imaging 2020;51:1556-1567. [ABSTRACT FROM AUTHOR]

Background: Accurate risk stratification of men with a clinical suspicion of prostate cancer (cSPCa) remains challenging despite the increasing use of MRI.Purpose: To evaluate the diagnostic accuracy of a unique biparametric MRI protocol (IMPROD bpMRI) combined with clinical and molecular markers in men with cSPCa.Study Type: Prospective single-institutional clinical trial (NCT01864135).Subjects: Eighty men with cSPCa.Field Strength/sequence: 3T, surface array coils. Two T2 -weighted and three diffusion-weighted imaging (DWI) acquisitions: 1) b-values 0, 100, 200, 300, 500 s/mm2 ; 2) b-values 0,1500 s/mm2 ; 3) b-values 0, 2000 s/mm2 .Assessment: IMPROD bpMRI examinations were qualitatively (IMPROD bpMRI Likert score) and quantitatively (DWI-based Gleason grade score) prospectively reported. Men with IMPROD bpMRI Likert 3-5 had two targeted biopsies followed by 12-core systematic biopsies (SB); those with IMPROD bpMRI Likert 1-2 had only SB. Additionally, 2-core from normal-appearing prostate areas were obtained for the mRNA expression of ACSM1, AMACR, CACNA1D, DLX1, PCA3, PLA2G7, RHOU, SPINK1, SPON2, TMPRSS2-ERG, and TDRD1 measured by quantitative reverse-transcription polymerase chain reaction.Statistical Tests: Univariate and multivariate analysis using regularized least-squares, feature selection and tournament leave-pair-out cross-validation (TLPOCV), as well as 10 random splits of the data in training-testing sets, were used to evaluate the mRNA, clinical and IMPROD bpMRI parameters in detecting clinically significant prostate cancer (SPCa) defined as Gleason score ≥ 3 + 4. The evaluation metric was the area under the curve (AUC).Results: IMPROD bpMRI Likert demonstrated the highest TLPOCV AUC of 0.92. The tested clinical variables had AUC 0.56-0.73, while the mRNA and additional IMPROD bpMRI parameters had AUC 0.50-0.67 and 0.65-0.89 respectively. The combination of clinical and mRNA biomarkers produced TLPOCV AUC of 0.87, the highest TLPOCV performance without including IMPROD bpMRI Likert.Data Conclusion: The qualitative IMPROD bpMRI Likert score demonstrated the highest accuracy for SPCa detection compared with the tested clinical variables and mRNA biomarkers.Level Of Evidence: 1 Technical Efficacy Stage: 2 J. Magn. Reson. Imaging 2020;51:1540-1553. [ABSTRACT FROM AUTHOR]

Background: Biochemical recurrence (BCR) affects a significant proportion of patients who undergo robotic-assisted laparoscopic prostatectomy (RALP).Purpose: To evaluate the performance of a routine clinical prostate multiparametric magnetic resonance imaging (mpMRI) and Decipher genomic classifier score for prediction of biochemical recurrence in patients who underwent RALP.Study Type: Retrospective cohort study.Subjects: Ninety-one patients who underwent RALP performed by a single surgeon, had mpMRI before RALP, Decipher taken from RALP samples, and prostate specific antigen (PSA) follow-up for >3 years or BCR within 3 years, defined as PSA >0.2 mg/ml. FIELD STRENGTH/SEQUENCE: mpMRI was performed at 27 different institutions using 1.5T (n = 10) or 3T scanners and included T2 w, diffusion-weighted imaging (DWI), or dynamic contrast-enhanced (DCE) MRI.Assessment: All mpMRI studies were reported by one reader using Prostate Imaging Reporting and Data System v. 2.1 (PI-RADsv2.1) without knowledge of other findings. Eighteen (20%) randomly selected cases were re-reported by reader B to evaluate interreader variability.Statistical Tests: Univariate and multivariate analysis using greedy feature selection and tournament leave-pair-out cross-validation (TLPOCV) were used to evaluate the performance of various variables for prediction of BCR, which included clinical (three), systematic biopsy (three), surgical (six: RALP Gleason Grade Group [GGG], extracapsular extension, seminal vesicle invasion, intraoperative surgical margins [PSM], final PSM, pTNM), Decipher (two: Decipher score, Decipher risk category), and mpMRI (eight: prostate volume, PSA density, PI-RADv2.1 score, MRI largest lesion size, summed MRI lesions' volume and relative volume [MRI-lesion-percentage], mpMRI ECE, mpMRI seminal vesicle invasion [SVI]) variables. The evaluation metric was the area under the curve (AUC).Results: Forty-eight (53%) patients developed BCR. The best-performing individual features with TLPOCV AUC of 0.73 (95% confidence interval [CI] 0.64-0.82) were RALP GGG, MRI-lesion-percentage followed by biopsy GGG (0.72, 0.62-0.82), and Decipher score (0.71, 0.60-0.82). The best performance was achieved by feature selection of Decipher+Surgery and MRI + Surgery variables with TLPOCV AUC of 0.82 and 0.81, respectively DATA CONCLUSION: Relative lesion volume measured on a routine clinical mpMRI failed to outperform Decipher score in BCR prediction.Level Of Evidence: 3 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2020;51:1075-1085. [ABSTRACT FROM AUTHOR]

Background: Interpretation of diffusion in conjunction with T2 -weighted MRI is essential for assessing prostate cancer; however, the combination of apparent diffusion coefficient (ADC) with quantitative T2 mapping remains unexplored.Purpose: To document the T2 components and ADC of untreated and irradiated nonmalignant prostate tissue as a measure of their glandular luminal and cellular compartments and to compare values with those of tumor.Study Type: Prospective.Population: Twenty-four men with prostate cancer (14 untreated; 10 with biochemical recurrence following radiation therapy).Field Strength/sequences: Endorectal 3 T MRI including a 32-echo gradient echo and spin echo (GRASE) and an 8 b-value diffusion-weighted sequence.Assessment: Regions of interest were drawn on ADC maps and T2 -weighted images around focal lesions in areas of biopsy-positive prostate cancer and in nonmalignant areas of untreated and irradiated peripheral zone (PZ), and untreated transitional zone (TZ). Multiecho T2 data were fitted with mono-/biexponential decay and nonnegative least squares functions. The luminal water fraction (LWF) was derived.Statistical Tests: The preference between mono- and biexponential decay was assessed using the Bayesian information criterion. Differences in fitted parameters between tissue types were compared (paired t-test within groups, Kruskal-Wallis and Wilcoxon rank-sum test between groups) and correlations between ADC and T2 components assessed (Spearman rank correlation test).Results: LWF in tumor (0.09) was significantly lower than in PZ or TZ (0.27 and 0.18, P < 0.01, respectively), but tumor values were comparable to nonmalignant irradiated prostate (0.08). The short T2 relaxation rate was lower in tumor than in nonmalignant untreated or irradiated tissue (significant compared with TZ, P = 0.01). There was a strong correlation between LWF and ADC in normal untreated tissue (r = 0.88, P < 0.001). This relationship was absent in nonmalignant irradiated prostrate (r = -0.35, P = 0.42) and in tumor (r = -0.04, P = 0.88).Data Conclusion: T2 components in conjunction with ADC can be used to characterize untreated and irradiated nonmalignant prostate and tumor. LWF is most useful at discriminating tumor in the untreated prostate.Level Of Evidence: 2 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2019;50:619-627. [ABSTRACT FROM AUTHOR]

The following is an illustrative review of common pitfalls in liver MRI that may challenge interpretation. This article reviews common technical and diagnostic challenges encountered when interpreting dynamic multiphasic T1 -weighted imaging, hepatobiliary phase imaging, and diffusion-weighted imaging of the liver. Additionally, each section includes suggestions for avoiding diagnostic and technical errors. Level of Evidence: 5 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2019;49:41-58. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the diagnostic value of dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) for patients with atypical ductal hyperplasia (ADH) in predicting malignant upgrade.Materials and Methods: 3T DCE-MRI was performed for 17 patients with ADH (median age 52, range 42-76) proven by stereotactic biopsy (n = 15), and ultrasound-guided biopsy (n = 2) from January 2011 to April 2015. All patients underwent surgical excision after the MRI. Two radiologists prospectively reviewed the MRI to determine the presence or absence of suspicious findings at the site of biopsy, and evaluated the MR features of any lesion present according to the Breast Imaging Reporting and Data System (BI-RADS) lexicon. MRI findings and clinical information were correlated with the final surgical pathology by multivariate analysis.Results: Nine of 17 lesions were upgraded to malignancy. MRI demonstrated suspicious nonmass enhancement (NME) at the site of biopsy in all upgraded patients. The median size was 19.5 mm (range, 9-44 mm). In the eight patients without upgrade, no enhancement (n = 2), linear enhancement along the biopsy track (n = 4), thin rim enhancement around hematoma (n = 1), and a focal NME (n = 1) were seen. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of MRI findings were 100, 87.5, 90, and 100%, respectively. Multivariate analysis revealed that the presence of suspicious enhancement on MRI was the most significant predictor of upgrade to malignancy (P = 0.0006) CONCLUSION: Our study revealed a high NPV of DCE-MRI for patients with ADH in terms of malignant upgrade at subsequent surgery. This suggests that patients with ADH without suspicious enhancement on DCE-MRI might be followed with DCE-MRI rather than undergoing surgical excision.Level Of Evidence: 1 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2017;46:1738-1747. [ABSTRACT FROM AUTHOR]

Purpose: To determine potential associations between histologic features of pediatric nonalcoholic fatty liver disease (NAFLD) and estimated quantitative magnetic resonance diffusion-weighted imaging (DWI) parameters.Materials and Methods: This prospective, cross-sectional study was performed as part of the Magnetic Resonance Assessment Guiding NAFLD Evaluation and Treatment (MAGNET) ancillary study to the Nonalcoholic Steatohepatitis Clinical Research Network (NASH CRN). Sixty-four children underwent a 3T DWI scan (b-values: 0, 100, and 500 s/mm2 ) within 180 days of a clinical liver biopsy of the right hepatic lobe. Three parameters were estimated in the right hepatic lobe: apparent diffusion coefficient (ADC), diffusivity (D), and perfusion fraction (F); the first assuming exponential decay and the latter two assuming biexponential intravoxel incoherent motion. Grading and staging of liver histology were done using the NASH CRN scoring system. Associations between histologic scores and DWI-estimated parameters were tested using multivariate linear regression.Results: Estimated means ± standard deviations were: ADC: 1.3 (0.94-1.8) × 10-3 mm2 /s; D: 0.82 (0.56-1.0) × 10-3 mm2 /s; and F: 17 (6.0-28)%. Multivariate analyses showed ADC and D decreased with steatosis and F decreased with fibrosis (P < 0.05). Associations between DWI-estimated parameters and other histologic features were not significant: ADC: fibrosis (P = 0.12), lobular inflammation (P = 0.20), portal inflammation (P = 0.27), hepatocellular inflammation (P = 0.29), NASH (P = 0.30); D: fibrosis (P = 0.34), lobular inflammation (P = 0.84), portal inflammation (P = 0.76), hepatocellular inflammation (P = 0.38), NASH (P = 0.81); F: steatosis (P = 0.57), lobular inflammation (P = 0.22), portal inflammation (P = 0.42), hepatocellular inflammation (P = 0.59), NASH (P = 0.07).Conclusion: In children with NAFLD, steatosis and fibrosis have independent effects on DWI-estimated parameters ADC, D, and F. Further research is needed to determine the underlying mechanisms and clinical implications of these effects.Level Of Evidence: 1 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2017;46:1149-1158. [ABSTRACT FROM AUTHOR]

Liver fibrosis is characterized by the accumulation of extracellular matrix proteins such as collagen in the liver interstitial space. All causes of chronic liver disease may lead to fibrosis and cirrhosis. The severity of liver fibrosis influences the decision to treat or the need to monitor hepatic or extrahepatic complications. The traditional reference standard for diagnosis of liver fibrosis is liver biopsy. However, this technique is invasive, associated with a risk of sampling error, and has low patient acceptance. Imaging techniques offer the potential for noninvasive diagnosis, staging, and monitoring of liver fibrosis. Recently, several of these have been implemented on ultrasound (US), computed tomography, or magnetic resonance imaging (MRI). Techniques that assess changes in liver morphology, texture, or perfusion that accompany liver fibrosis have been implemented on all three imaging modalities. Elastography, which measures changes in mechanical properties associated with liver fibrosis-such as strain, stiffness, or viscoelasticity-is available on US and MRI. Some techniques assessing liver shear stiffness have been adopted clinically, whereas others assessing strain or viscoelasticity remain investigational. Further, some techniques are only available on MRI-such as spin-lattice relaxation time in the rotating frame (T1 ρ), diffusion of water molecules, and hepatocellular function based on the uptake of a liver-specific contrast agent-remain investigational in the setting of liver fibrosis staging. In this review, we summarize the key concepts, advantages and limitations, and diagnostic performance of each technique. The use of multiparametric MRI techniques offers the potential for comprehensive assessment of chronic liver disease severity.Level Of Evidence: 5 J. MAGN. RESON. IMAGING 2017;45:1276-1295. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the diagnostic performances of the diffusion tensor imaging (DTI) parameters in the diagnosis of breast cancer and to investigate the variations in DTI parameters according to the breast cancer biomarkers.Materials and Methods: At 3.0 Tesla (T), DTI was performed in 85 patients with 92 enhancing breast lesions. λ1 , λ2 , λ3 , mean diffusivity (MD), radial diffusivity (RD), fractional anisotropy (FA), relative anisotropy (RA), and geodesic anisotropy (GA) were studied and compared with diffusion-weighted imaging-derived apparent diffusion coefficient. Lesions were analyzed according to BIRADS lexicon. Logistic regression models were constructed to determine the contribution of DTI to the specificity and the accuracy of DCE-MRI. Breast cancer biomarkers; estrogen receptor (ER), HER-2 status, and Ki-67 were correlated with DTI in malignant cases.Results: Malignant lesions exhibited significantly lower MD, RD, λ1 , λ2 , λ3 and higher FA, RA, GA values (P <  0.001). Logistic regression models showed that MD, RD, λ1 , λ2 , λ3 , FA, and RA increase the specificity of the DCE-MRI (from 83.0% to 89.4-93.6%; P <  0.05). Higher RD, λ2 , λ3 and lower FA, RA, and GA values were observed in ER-negative breast cancer (P <  0.05). Ki-67 showed significant, negative correlation with FA, RA, GA, λ1 -λ3 and λ1 -λ2 (r = -0.336 to -0.435; P <  0.05).Conclusion: Besides its ability to differentiate malignant breast lesions, DTI improves the specificity of conventional 3.0T breast MRI and shows correlation with biomarkers ER and Ki-67.Level Of Evidence: 1 J. Magn. Reson. Imaging 2017;45:660-672. [ABSTRACT FROM AUTHOR]

Purpose: To explore the association between quantitative parameters derived from dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and diffusion-weighted imaging (DWI) and Ki-67 proliferation status in patients with estrogen receptor (ER)-positive invasive breast cancer.Materials and Methods: We retrospectively reviewed the records of 88 patients with ER-positive invasive breast cancer who underwent preoperative DCE-MRI and DWI on a 3T scanner. Perfusion parameters (Ktrans , Kep , and Ve ) and apparent diffusion coefficients (ADCs) were recorded, and we correlated these data with the Ki-67 status. The Ki-67 proliferation index was categorized as high (≥14%) or low (<14%).Results: In the high-Ki-67 group, the mean Ktrans was significantly higher (P < 0.001) than that of the low-Ki-67 group, and the mean ADC significantly lower (P < 0.001). However, the mean Kep and Ve values did not differ between the two groups (P = 0.248 and P = 0.055, respectively). Univariate analysis showed that a higher Ktrans (>0.274), a lower ADC (≤0.893 × 10-3 mm2 /s), a larger tumor size (>2 cm), a higher histological grade (grade 3), the presence of axillary metastasis, and positive P53 status were significantly associated with high-Ki-67 status (all P values < 0.05). Of these variables, a higher Ktrans (>0.274; adjusted odds ratio [OR] = 9.027, 95% confidence interval [CI] = 1.929-42.245; P = 0.005) and a higher histological grade (grade 3; adjusted OR = 7.510, 95% CI = 1.305-43.205; P = 0.024) independently predicted a high Ki-67 status.Conclusion: Ktrans derived from DCE-MRI is associated independently with the Ki-67 proliferation status in patients with ER-positive invasive breast cancer.Level Of Evidence: 4 J. Magn. Reson. Imaging 2017;45:94-102. [ABSTRACT FROM AUTHOR]

Purpose: To quantitatively compare the apparent diffusion coefficient (ADC) values of 3.0T and 1.5T magnetic resonance (MR) diffusion-weighted imaging (DWI) protocols using regions of interest (ROIs) for the minimum ADC, largest solid part, and maximum diameter of lesions, for the detection of liver focal lesions.Materials and Methods: In total, 26 patients with 28 liver focal lesions prospectively underwent both 1.5T and 3.0T DWI of the liver. The protocols included respiratory-triggered (RT), breath-holding (BH), and free-breathing (FB) acquisitions. The ADC values were measured at both field strengths using three methods: ROIs with the minimum ADC, the largest solid part, and the maximum diameter of lesions. Bland-Altman tests and paired t-tests were used to compare ADC values in the liver focal lesions obtained at 1.5T and 3.0T.Results: The 3.0T and 1.5T protocols differed significantly with regard to the ADC values of the RT, BH, and FB acquisitions, for ROIs of both the largest solid part (P = 0.005, P = 0.014, and P = 0.022, respectively) and maximum diameter of lesions (P < 0.001, P = 0.001, and P = 0.001, respectively).Conclusion: When using DWI for quantitative analysis of liver focal lesions, field strength could exert a negative effect depending on the ROI. The ADC values from ROIs of both the largest solid part and maximum diameter of lesions may differ between 1.5T and 3.0T protocols.J. Magn. Reson. Imaging 2016;44:1320-1329. [ABSTRACT FROM AUTHOR]

Purpose: To explore the value of T1 relaxation times in the rotating frame (T1 ρ or T1 rho) for evaluating liver fibrosis stage, compared to apparent diffusion coefficients (ADCs). Materials and Methods: Liver fibrosis in model rats (n = 50) was produced by carbon tetrachloride (CCl4 ) injection. Five rats died during the experiment. Surviving model rats (n = 45) and controls (n = 15) were subjected to 3.0T MRI and the ADCs (b-values: 0, 800 s/mm(2) ) and T1 ρ values were determined. Liver fibrosis stage (F0-F4) was defined based on METAVIR scoring. Nonparametric statistical methods and receiver operating characteristic (ROC) curve analyses were employed to determine diagnostic accuracy. Results: Mean ADC and T1 ρ associated negatively (r = -0.732 P < 0.001) and positively (r = 0.863 P < 0.001), respectively, with severity of fibrosis stage. Analysis of ROC curves for fibrosis staging showed that the area under the curve (AUC) for T1 ρ (stage F0 vs. F1-F4 = 0.976, stage F0-F1 vs. F2-F4 = 0.920, stage F0-F2 vs. F3-F4 = 0.938, and stage F0-F3 vs. F4 = 0.931) was larger than that for ADCs (0.917, 0.924, 0.842, and 0.781, respectively). Conclusion: ADC and T1 ρ values correlate with liver fibrosis stage. The performance of the T1 ρ parameter was superior to that of the ADC parameter in the differentiation of liver fibrosis stages in a CCl4 rat model. [ABSTRACT FROM AUTHOR]

Magnetic resonance (MR) enterography has become a fundamental tool for small bowel evaluation. Multiphasic cine imaging is a useful component of MR enterography evaluation because it provides functional information about bowel motility. Cine MR enterography can be used to evaluate for strictures and adhesions. Bowel motility evaluation has been shown to increase pathologic lesion detection in Crohn's disease and has been incorporated into disease activity scoring systems. Currently, cine MR enterography remains underutilized. The purpose of this article is to outline how to perform and interpret cine MR enterography. The authors describe how to perform a multiphasic balanced steady state free precession sequence using different MR systems and give practical advice on how to display and interpret the cine sequence. Sample cases illustrate how the cine sequence complements standard MR enterography evaluation with T2 -weighted, contrast-enhanced T1 -weighted, and diffusion-weighted imaging. [ABSTRACT FROM AUTHOR]

Purpose: To explore the characteristics of intravoxel incoherent motion (IVIM) in various stages of liver fibrosis, and their relationships with fibrotic stages in rats. Materials and Methods: Fifty rats were given various doses of carbon tetrachloride (CCl4 ) to induce various fibrotic stages in rats; 15 untreated rats served as controls. Diffusion-weighted magnetic resonance imaging (MRI) was performed and eight b-values (0-800 s/mm(2) ) were applied to obtain IVIM parameters (D, pure molecular diffusion; f, perfusion fraction; D*, pseudodiffusion). The stages of liver fibrosis (stages F0-F4) were evaluated histologically using METAVIR scores. Fifty-seven rats (15 controls and 42 with fibrosis) were analyzed by nonparametric methods and receiver operating characteristic curves to determine diagnostic accuracy. Results: Significant differences (P < 0.001) were found between stages (stages F0-F4) by D, f, D*, and apparent diffusion coefficient (ADC). There were inverse correlations between fibrosis stages and D, f, D*, ADC (r = -0.657, r = -0.631, r = -0.711 r = -0.719, respectively). Multivariate analysis showed that the combination models (D, f, D*) were better than the individual parameter (ADC) for the evaluation fibrosis stages (area under the curve [AUC]: 0.821-1.000 vs. AUC: 0.753-0.918) CONCLUSION: IVIM-derived parameters showed significant correlations with stages of liver fibrosis in a rat model. [ABSTRACT FROM AUTHOR]

Purpose To evaluate the use of intravoxel incoherent motion (IVIM) imaging for staging hepatic fibrosis, and compare its staging ability with that of magnetic resonance elastography (MRE). Materials and Methods This study included 129 patients with pathologically staged liver fibrosis, and 53 patients with healthy livers. All patients underwent both MRE and IVIM imaging. Four diffusivity indices were calculated with 11 b-values; slow diffusion coefficient related to molecular diffusion (D), fast diffusion coefficient related to perfusion in micro-vessels (D*), perfusion-related diffusion fraction (f), and apparent diffusion coefficient (ADC). Receiver operating characteristic curve analysis was performed to determine the accuracy of IVIM imaging and MRE for staging hepatic fibrosis. Results D*, f, and ADC values decreased significantly with fibrosis stage ( P < 0.0124), and liver stiffness increased ( P < 0.0001). The Az value of MRE was significantly higher than that of D* for all fibrosis stages (D* vs. MRE for ≥ F1, 0.851 vs. 0.992 [ P < 0.0001]; ≥ F2, 0.898 vs. 0.998 [ P = 0.0003]; ≥ F3, 0.904 vs. 0.995 [ P = 0.0004]; F4, 0.885 vs. 0.996 [ P < 0.0001]). Conclusion IVIM imaging is a useful technique for evaluating hepatic fibrosis, but MRE is better able to discriminate fibrosis stages than IVIM imaging. J. Magn. Reson. Imaging 2015;42:204-210. © 2014 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Purpose To develop and implement an automated algorithm for visualizing and quantifying bowel motility using cine magnetic resonance imaging (MRI). Materials and Methods Four healthy volunteers as well as eight patients with suspected or diagnosed inflammatory bowel disease (IBD) underwent MR examinations on a 1.5T scanner. Coronal T2-weighted cine MR images were acquired in healthy volunteers without and with intravenous (i.v.) administration of butylscopolamine. In patients with IBD, cine MRI sequences were collected prior to standard bowel MRI. Bowel motility was assessed using an optical flow algorithm. The resulting motion vector magnitudes were presented as bowel motility maps. Motility changes after i.v. administration of butylscopolamine were measured in healthy volunteers. Inflamed bowel segments in patients were correlated with motility map findings. Results The acquisition of bowel motility maps was feasible in all subjects examined. In healthy volunteers butylscopolamine led to quantitatively measurable decrease in bowel motility (mean decrease of 59%; P = 0.171). In patients with IBD, visualization of bowel movement by color-coded motility mapping allowed for the detection of segments with abnormal bowel motility. Inflamed bowel segments could be identified by exhibiting a decreased motility. Conclusion Our method is a feasible and promising approach for the assessment of bowel motility disorders. J. Magn. Reson. Imaging 2015;41:354-360.© 2013 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Purpose To determine the value of adding diffusion-weighted imaging (DWI) to conventional magnetic resonance cholangiopancreatography (MRCP) for differentiating benign from malignant distal biliary strictures. Materials and Methods Two independent readers reviewed three image sets (1: MRCP alone; 2: MRCP and DWI combined; and 3: MRCP, DWI, and contrast-enhanced T1-weighted imaging [T1WI] combined) of 60 patients with suspected distal biliary strictures and rated the probability of malignancy. Diagnostic performance and accuracy were compared using the receiver operating characteristic (ROC) curves and McNemar two-tailed test. κ coefficients were calculated to assess the interobserver agreement. Results The Az value and accuracy improved significantly after additional review of DWI for both readers: Az = 0.780 vs. 0.916 ( P = 0.003) for Reader 1 and 0.784 vs. 0.853 ( P = 0.037) for Reader 2; accuracy = 69% vs. 93% for Reader 1 ( P < 0.001) and 57% vs. 85% for Reader 2 ( P = 0.002). No significant difference in the Az values and accuracy was found between MRCP and DWI combined, and MRCP, DWI, and contrast-enhanced T1WI combined ( P > 0.050). There was substantial interobserver agreement in all three image sets (κ = 0.695-0.732). Conclusion The addition of DWI to MRCP significantly improved diagnostic accuracy in the characterization of distal biliary strictures. J. Magn. Reson. Imaging 2014;39:1509-1517. © 2013 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Purpose To assess the diagnostic performance of multiparametric MRI (mpMRI), in the detection of prostate cancer, including morphologic sequences (mMRI), diffusion-weighted imaging (DWI), and MR spectroscopy (MRS). Combined morphological and functional MRI scoring systems was used for urological-radiological work-up of patients with a prostate-specific antigen (PSA) value ≤ 10 ng/mL. Materials and Methods The study included 136 of 200 consecutive patients with PSA values between 2.5 and 4 ng/mL and an abnormal digital rectal examination (DRE), or patients with PSA values between 4 and 10 ng/mL, independently from DRE. Each patient provided informed consent to undergo at serum free/total PSA ratio (f/t PSA) assay, mMRI, MRS, DWI, and transrectal ultrasonography (TRUS) biopsy. The MRI datasets were scored singularly; then mMRI and DWI, mMRI and MRS data were combined in a coupled score, and finally mMRI, DWI, and MRS data were combined in a single score (cMRI score). Results Scores were correlated to negative biopsies and significant/insignificant Gleason score biopsies. Receiver-operator-characteristic curve and McNemar tests were performed. Cancer was diagnosed in 18% of patients. The cMRI score showed: (i) the highest sensitivity (0.84) and negative predictive value (0.93); (ii) a significant correlation with Gleason score; and (iii) a statistically different median value between significant and insignificant Gleason score. Conclusion The cMRI score could identify patients with a PSA≤10 ng/mL who will have a negative work-up, for its high negative predictive value, and patients at high risk for significant prostate cancer because of its correlation with the Gleason score. J. Magn. Reson. Imaging 2014;39:1206-1212. © 2013 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Purpose To employ the stretched exponential and diffusional kurtosis models to study the non-Gaussian behavior of diffusion-related signal decay of the liver in an animal model of hepatic fibrosis. Materials and Methods High b-value diffusion imaging data (up to 3500 s/mm2) of ex vivo murine liver specimens was acquired using a 9.4 T MRI scanner. A simple monoexponential model as well as the stretched exponential and diffusional kurtosis models were employed to analyze the diffusion data, the results of which were correlated with liver histopathology. Results Strong correlations between histopathological assessments of hepatic fibrosis and parameters derived from the stretched exponential and diffusional kurtosis models were found. Using Akaike's Information Criterion (AIC) analyses, the kurtosis model was found to result in an improved fit of the high b-value diffusion data when compared to both the monoexponential and stretched exponential models. Conclusion The use of diffusional kurtosis or stretched exponential models, applied to the characterization of the non-Gaussian behavior of the molecular diffusion of liver exhibited over an extended b-factor range, affords the potential for an increased capability of magnetic resonance imaging (MRI) in the characterization of chronic liver disease. J. Magn. Reson. Imaging 2014;39:827-834. © 2013 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Purpose To investigate the efficacy of the double inversion recovery sequence (DIR) in breast cancer detection. Materials and Methods Fifty-six patients with biopsy-proven breast cancers underwent preoperative breast MRI, including sagittal DIR and contrast-enhanced T1-weighted images (CE-T1WI). Twenty-four of the 56 patients additionally underwent sagittal T1WI and T2WI. The signal intensities of the lesion (L) and ipsilateral normal breast tissue (N) were measured. The lesion-to-normal ratio (LNR) was defined as LNR = 100(L-N)/N. We compared LNRs among the four sequences, and then assessed the differences of LNRs between CE-T1WI and DIR in each pathologic subgroup (IDC and non-IDC group). Multiple regression analysis was performed to identify predictors of the signal-to-noise ratios (SNR) of the normal tissue or lesion and LNRs. Results The mean LNR did not differ significantly between DIR (58.65 ± 71.55) and CE-T1WI (59.78 ±31.04), nor did the LNRs between DIR and CE-T1WI in the two subgroups. The LNRs of DIR did not differ significantly between the two subgroups ( P = 0.247). The SNR of lesions in DIR was correlated with the intraductal component percentage (r2 = 0.485, P = 0.037). Conclusion DIR and CE-T1WI showed similar tumor detection efficacy, and DIR could complement dynamic MRI for detecting breast cancer without a contrast agent. J. Magn. Reson. Imaging 2014;39:51-58. © 2013 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Purpose To validate a software prototype allowing for small bowel motility analysis in free breathing by comparing it to manual measurements. Materials and Methods In all, 25 patients (15 male, 10 female; mean age 39 years) were included in this Institutional Review Board-approved, retrospective study. Magnetic resonance imaging (MRI) was performed on a 1.5T system after standardized preparation acquiring motility sequences in free breathing over 69-84 seconds. Small bowel motility was analyzed manually and with the software. Functional parameters, measurement time, and reproducibility were compared using the coefficient of variance and paired Student's t-test. Correlation was analyzed using Pearson's correlation coefficient and linear regression. Results The 25 segments were analyzed twice both by hand and using the software with automatic breathing correction. All assessed parameters significantly correlated between the methods ( P < 0.01), but the scattering of repeated measurements was significantly ( P < 0.01) lower using the software (3.90%, standard deviation [SD] ± 5.69) than manual examinations (9.77%, SD ± 11.08). The time needed was significantly less ( P < 0.001) with the software (4.52 minutes, SD ± 1.58) compared to manual measurement, lasting 17.48 minutes for manual (SD ± 1.75 minutes). Conclusion The use of the software proves reliable and faster small bowel motility measurements in free-breathing MRI compared to manual analyses. The new technique allows for analyses of prolonged sequences acquired in free breathing, improving the informative value of the examinations by amplifying the evaluable data. J. Magn. Reson. Imaging 2014;39:17-23. © 2013 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

MR enterography is playing an evolving role in the evaluation of small bowel Crohn's disease (CD). Standard MR enterography includes a combination of rapidly acquired T2 sequence, balanced steady-state acquisition, and contrast enhanced T1-weighted gradient echo sequence. The diagnostic performance of these sequences has been shown to be comparable, and in some respects superior, to other small bowel imaging modalities. The findings of CD on MR enterography have been well described in the literature. New and emerging techniques such as diffusion-weighted imaging (DWI), dynamic contrast enhanced MRI (DCE-MRI), cinematography, and magnetization transfer, may lead to improved accuracy in characterizing the disease. These advanced techniques can provide quantitative parameters that may prove to be useful in assessing disease activity, severity, and response to treatment. In the future, MR enterography may play an increasing role in management decisions for patients with small bowel CD; however, larger studies are needed to validate these emerging MRI parameters as imaging biomarkers. J. Magn. Reson. Imaging 2013;37:1277-1289. © 2013 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Purpose: To compare diffusivity values between malignant and benign focal hepatic lesions using the intravoxel incoherent motion model. Materials and Methods: This study included 84 focal hepatic lesions in 84 patients. Final diagnoses were as follows: hepatocellular carcinoma ( n = 45), cholangiocarcinoma ( n = 6), metastatic liver tumor ( n = 3), cyst ( n = 20), hemangioma ( n = 5), inflammatory pseudotumor ( n = 2), abscess ( n = 2), and focal nodular hyperplasia ( n = 1). Diffusion-weighted images at 12 b-values were used to obtain the diffusion coefficient of pure molecular diffusion (D), diffusion coefficient of microcirculation or perfusion-related diffusion (D*), and perfusion-related diffusion fraction (f). Parameters of malignant and benign focal hepatic lesions were compared using the Wilcoxon test. The diagnostic performance for distinguishing between malignant and benign hepatic lesions was also analyzed. Results: Both the D value (1.15 ± 0.21 × 10−3 mm2/s [mean ± standard deviation]) and D* value (62.7 ±12.7 × 10−3 mm2/s) in malignant lesions was significantly lower than that in benign lesions (D value [2.46 ± 0.45× 10−3 mm2/s], P < 0.0001; D* value [87.6 ± 35.3 × 10−3 mm2/s], P = 0.0008). The f value did not differ significantly between malignant (25.0 15.1 ± 15.1%) and benign lesions (30.1 ± 16.3%). Conclusion: D* and D values were suppressed in malignant lesions. However, the D value was more reliable for distinguishing between malignant and benign focal hepatic lesions. J. Magn. Reson. Imaging 2013;37:1371-1376. © 2012 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Purpose: To assess the effect of motion artifact reduction on the diffusion-weighted magnetic resonance imaging (DWI-MRI) of the liver, we compared velocity-compensated DWI (VC-DWI) and VC-DWI combined with tetrahedral gradients (t-VC-DWI) to conventional DWI (c-DWI) in the assessment of apparent diffusion coefficients (ADCs) of the liver. Materials and Methods: In 12 healthy volunteers, the liver was scanned with c-DWI, VC-DWI, and t-VC-DWI sequences. The signal-to-noise ratio (SNR) and ADC of the liver parenchyma were measured and compared among sequences. Results: The image quality was visually better for t-VC-DWI than for the others. The SNR for t-VC-DWI was significantly higher than that for VC-DWI ( P < 0.05) and comparable to that for c-DWI. ADCs in both hepatic lobes were significantly lower for t-VC-DWI than for c-DWI ( P < 0.01). ADC in the left lobe was significantly lower for VC-DWI than for c-DWI ( P < 0.01). Although ADC in the left lobe was significantly higher for c-DWI ( P < 0.01), no significant differences in ADCs were found between the right and left lobes for VC-DWI and t-VC-DWI. Conclusion: The use of a t-VC-DWI sequence enables us to correct ADCs of the liver for artificial elevation due to cardiac motion, with preserved SNR. J. Magn. Reson. Imaging 2013;37:172-178. © 2012 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Purpose: To characterize longitudinal changes in molecular water diffusion, blood microcirculation, and their contributions to the apparent diffusion changes using intravoxel incoherent motion (IVIM) analysis in an experimental mouse model of liver fibrosis. Materials and Methods: Liver fibrosis was induced in male adult C57BL/6N mice (22-25 g; n = 12) by repetitive dosing of carbon tetrachloride (CCl4). The respiratory-gated diffusion-weighted (DW) images were acquired using single-shot spin-echo EPI (SE-EPI) with 8 b-values and single diffusion gradient direction. True diffusion coefficient (Dtrue), blood pseudodiffusion coefficient (Dpseudo), and perfusion fraction (Pfraction) were measured. Diffusion tensor imaging (DTI) was also performed for comparison. Histology was performed with hematoxylin-eosin and Masson's trichrome staining. Results: A significant decrease in Dtrue was found at 2 weeks and 4 weeks following CCl4 insult, as compared with that before insult. Similarly, Dpseudo values before injury was significantly higher than those at 2 weeks and 4 weeks after CCl4 insult. Meanwhile, Pfraction values showed no significant differences over different timepoints. For DTI, significant decrease in ADC was observed following CCl4 administration. Fractional anisotropy at 2 weeks after CCl4 insult was significantly lower than that before insult, and subsequently normalized at 4 weeks after the insult. Liver histology showed collagen deposition, the presence of intracellular fat vacuoles, and cell necrosis/apoptosis in livers with CCl4 insult. Conclusion: Both molecular water diffusion and blood microcirculation contribute to the alteration in apparent diffusion changes in liver fibrosis. Reduction in Dtrue and Dpseudo values resulted from diffusion and perfusion changes, respectively, during the progression of liver fibrosis. IVIM analysis may serve as valuable and robust tool in detecting and characterizing liver fibrosis at early stages, monitoring its progression in a noninvasive manner. J. Magn. Reson. Imaging 2012;36:159-167. © 2012 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Purpose: To characterize changes in relaxation times of liver using quantitative magnetic resonance imaging (MRI) in an experimental mouse model of liver fibrosis. Quantitative MRI is a potentially robust method to characterize liver fibrosis. However, correlation between relaxation times and fibrosis stage has been controversial. Materials and Methods: Liver fibrosis was induced in male adult C57BL/6N mice (22-25 g; n = 12) by repetitive dosing of carbon tetrachloride (CCl4). The animals were examined with a series of spin-echo (SE) images with varying TRs and multiecho SE imaging sequence at 7 T before and 2, 4, 6, and 8 weeks after CCl4 insult. Hepatic T1 and T2 values were measured. Histology was performed with hematoxylin-eosin staining and Masson's trichrome staining. Results: Significant increase ( P < 0.001) in hepatic T1 was found at 2, 4, 6, and 8 weeks following CCl4 insult as compared with that before insult. Meanwhile, hepatic T2 at 2, 4, 6, and 8 weeks after CCl4 insult was significantly higher ( P < 0.001) than that before the insult. Liver histology showed collagen deposition, edema, and infiltration of inflammatory cells in livers with CCl4 insult. Conclusion: Both longitudinal and transverse relaxation times may serve as robust markers for liver fibrosis. With the advent of single breath-hold sequences for MR relaxometry, quantitative mapping of relaxation times can be routinely and reliably performed in abdominal organs and hence may be valuable and robust in detecting liver fibrosis at early phase and monitoring its progression. J. Magn. Reson. Imaging 2012;36:152-158. © 2012 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Purpose: To compare liver ADC obtained with breathhold and free-breathing diffusion weighted imaging (DWI) in healthy volunteers and patients with liver disease. Materials and Methods: Twenty-eight subjects, 12 healthy volunteers and 16 patients (9 NAFLD, 7 chronic active HCV), underwent breathhold (BH) and free-breathing (FB) DWI MRI at 1.5 Tesla. Pearson's correlation coefficient was used to determine correlation while paired t-tests assessed differences between BH and FB ADC. Estimated bias was calculated using the Bland-Altman method. Results: Liver ADC (×10−3 mm2/s) was lower on BH for all groups (mean difference 0.36 ± 0.20; P < 0.01). ADC was higher in healthy volunteers (BH 1.80 ± 0.18; FB 2.24 ± 0.20) compared with NAFLD patients (BH 1.43 ± 0.27; FB 1.78 ± 0.28) ( P < 0.001) and HCV patients (BH 1.63 ± 0.191; FB 1.88 ± 0.12). Overall correlation between BH and FB ADC was (r = 0.75), greatest in NAFLD (r = 0.90) compared with the correlation in HCV (r = 0.24) and healthy subjects (r = 0.34). Bland-Altman plots did not show agreement in mean absolute difference and estimated bias between subjects. Conclusion: Correlation between BH and FB liver ADC is moderate indicating that BH and FB should not be used interchangeably. Additionally, the lower ADC values in BH versus FB should be accounted for when comparing different liver DWI studies. J. Magn. Reson. Imaging 2012;35:103-109. © 2011 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Purpose To compare single-shot echo-planar imaging (SS EPI) diffusion-weighted MRI (DWI) of abdominal organs between 1.5 Tesla (T) and 3.0T in healthy volunteers in terms of image quality, apparent diffusion coefficient (ADC) values, and ADC reproducibility. Materials and Methods Eight healthy volunteers were prospectively imaged in this HIPAA-compliant IRB-approved study. Each subject underwent two consecutive scans at both 1.5 and 3.0T, which included breathhold and free-breathing DWI using a wide range of b-values (0 to 800 s/mm2). A blinded observer rated subjective image quality (maximum score= 8), and a separate observer placed regions of interest within the liver, renal cortices, pancreas, and spleen to measure ADC at each field strength. Paired Wilcoxon tests were used to compare abdominal DWI between 1.5T and 3.0T for specific combinations of organs, b-values, and acquisition techniques. Results Subjective image quality was significantly lower at 3.0T for all comparisons ( P = 0.0078- 0.0156). ADC values were similar at 1.5T and 3.0T for all assessed organs, except for lower liver ADC at 3.0T using b0-500-600 and breathhold technique. ADC reproducibility was moderate at both 1.5T and 3.0T, with no significant difference in coefficient of variation of ADC between field strengths. Conclusion Compared with 1.5T, SS EPI at 3.0T provided generally similar ADC values, however, with worse image quality. Further optimization of abdominal DWI at 3.0T is needed. J. Magn. Reson. Imaging 2011;33:128-135. © 2010 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

Purpose To characterize changes in diffusion properties of liver using diffusion tensor imaging (DTI) in an experimental model of liver fibrosis. Materials and Methods Liver fibrosis was induced in Sprague-Dawley rats ( n = 12) by repetitive dosing of carbon tetrachloride (CCl4). The animals were examined with a respiratory-gated single-shot spin-echo echo-planar DTI protocol at 7 T before, 2 weeks after, and 4 weeks after CCl4 insult. Apparent diffusion coefficient (ADC), directional diffusivities (ADC// and ADC⟂), and fractional anisotropy (FA) were measured. Liver histology was performed with hematoxylin-eosin staining and Masson's trichrome staining. Results Significant decrease ( P < 0.01) in ADC was found at 2 weeks (0.86 ± 0.09 × 10−3 mm2/s) and 4 weeks (0.74 ± 0.09 × 10−3 mm2/s) following CCl4 insult, as compared with that before insult (0.97 ± 0.08 × 10−3 mm2/s). Meanwhile, FA at 2 weeks (0.18 ± 0.03) after CCl4 insult was significantly lower ( P < 0.01) than that before insult (0.26 ± 0.05), and subsequently normalized at 4 weeks (0.26 ± 0.07) after the insult. Histology showed collagen deposition, presence of intracellular fat vacuoles, and cell necrosis/apoptosis in livers with CCl4 insult. Conclusion DTI detected the progressive changes in water diffusivities and diffusion anisotropy of liver tissue in this liver fibrosis model. ADC and FA are potentially valuable in detecting liver fibrosis at early stages and monitoring its progression. Future human studies are warranted to further verify the applicability of DTI in characterizing liver fibrosis and to determine its role in clinical settings. J. Magn. Reson. Imaging 2010;32:1141-1148. © 2010 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate apparent diffusion coefficient (ADC) values for characterization of a variety of focal liver lesions and specifically for differentiation of solid benign lesions (focal nodular hyperplasia [FNH] and adenomas) from solid malignant neoplasms (metastases and hepatocellular carcinoma [HCC]) in a large case series. Materials and Methods: A total of 542 lesions in 382 patients were evaluated. ADC values were measured in 166 hemangiomas, 112 hepatomas, 107 metastases, 95 cysts, 10 abscesses, 43 FNH, and nine adenomas. ADCs of 1.5 and 1.6 (×10−3 mm2/second) were selected as threshold values to separate benign and malignant lesions. Sensitivity, specificity, positive, and negative predictive values (PPV, NPV) were calculated. Comparisons were carried out with studentized range test. Results: There was high interobserver agreement in ADC measurements for all lesion types. The mean ADCs for cysts was 3.40 (×10 −3 mm2/second), hemangiomas 2.26, FNH 1.79, adenomas 1.49, abscesses 1.97, HCC 1.53, and metastases 1.50. The mean ADC for benign lesions was 2.50 and for malignant lesions was 1.52. Cysts were easily distinguished from other lesions. There was, however, overlap between solid benign and malignant lesions. Conclusion: Benign lesions have higher mean ADC values than malignant lesions. However, ADC values of solid benign lesions (FNH and adenomas) are similar to malignant lesions (metastases, HCC) limiting the value of diffusion weighted imaging (DWI) for differentiating solid liver masses. J. Magn. Reson. Imaging 2010;32:138-147. © 2010 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

Purpose: To quantify the accumulation of superparamagnetic iron oxide (SPIO) in patients with and without liver cirrhosis using T2 and T2* mapping. Materials and Methods: We enrolled 10 patients without liver cirrhosis and 30 patients with liver cirrhosis (Child-Pugh class A, n = 18; and B/C, n = 12). T2 and T2* mapping were performed before and after SPIO administration. The reductions in T2 (ΔT2) and T2* (ΔT2*) after SPIO administration were compared between the control and liver cirrhosis groups and the control, Child-Pugh A, and Child Pugh B/C groups. Results: There were significant differences in ΔT2 (22.2 ± 4.4 and 15.1 ± 7.0) and ΔT2* values (24.3 ± 3.3 and 16.8 ± 8.1) ( P = 0.005 and P < 0.001) between the control and the liver cirrhosis groups. There was a significant difference in the ΔT2* between the Child-Pugh A and Child-Pugh B/C groups ( P < 0.001) and in the ΔT2 and ΔT2* between the control and Child-Pugh B/C groups ( P = 0.018 and P < 0.001). Conclusion: ΔT2 and ΔT2* are significantly larger in patients without liver cirrhosis than those with liver cirrhosis. ΔT2* is also significantly larger in Child-Pugh class A patients than those in Child-Pugh B/C. J. Magn. Reson. Imaging 2010;31:1379-1386. © 2010 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

Purpose: To compare repeatability and reproducibility of four different methods of apparent diffusion coefficient (ADC) evaluation of liver parenchyma. In fact, repeatability and reproducibility assessment is mandatory in quantitative evaluations, however, these have not been accurately investigated in liver MR-diffusion-weighted studies. Materials and Methods: Diffusion-weighted sequences, b-value = 0-1000 s/mm2, were acquired on 30 healthy volunteers by a 1.5T scanner whose reliability has been validated by a phantom study. Four sampling methods, evaluating various parenchyma percentages by different-sized region-of-interests (ROIs), were compared by two observers: 70% and 30% of the volume, 4%-one-ROI-per-segment, and 4%-one-ROI-per-slice in the right-lobe. Ninety-five percent limits of agreement and intraclass correlation coefficient (ICC) were calculated. Results: Complete measurements on the left lobe could be obtained in less than half of patients. The 4%-one-ROI-per-slice and 4%-one-ROI-per-segment yielded lower mean values compared with 30-70% volume methods (1343-1373 versus 1463-1560·10−6 mm2/s, respectively). Repeatability was acceptable (ICCs ∼ 0.80) whereas reproducibility was low (ICCs ≤ 0.45) for all methods. Averaging at least 3 measurements in middle-lower sections of the right lobe improved both repeatability (ICCs to ≥0.87) and reproducibility (ICCs to 0.82) for 30-70% V methods. Conclusion: ADC measurements were repeatable but not reproducible in our study. Reproducibility could be improved by taking averages on the right lobe with large ROI methods. Studies on procedures that standardize ADC measurements using more than two observers are needed. J. Magn. Reson. Imaging 2010;31:912-920. ©2010 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

Purpose: To report our preliminary experience with the use of intravoxel incoherent motion (IVIM) diffusion-weighted magnetic resonance imaging (DW-MRI) and dynamic contrast-enhanced (DCE)-MRI alone and in combination for the diagnosis of liver cirrhosis. Materials and Methods: Thirty subjects (16 with noncirrhotic liver, 14 with cirrhosis) were prospectively assessed with IVIM DW-MRI ( n = 27) and DCE-MRI ( n = 20). IVIM parameters included perfusion fraction (PF), pseudodiffusion coefficient (D*), true diffusion coefficient (D), and apparent diffusion coefficient (ADC). Model-free DCE-MR parameters included time to peak (TTP), upslope, and initial area under the curve at 60 seconds (IAUC60). A dual input single compartmental perfusion model yielded arterial flow (Fa), portal venous flow (Fp), arterial fraction (ART), mean transit time (MTT), and distribution volume (DV). The diagnostic performances for diagnosis of cirrhosis were evaluated for each modality alone and in combination using logistic regression and receiver operating characteristic analyses. IVIM and DCE-MR parameters were compared using a generalized estimating equations model. Results: PF, D*, D, and ADC values were significantly lower in cirrhosis ( P = 0.0056-0.0377), whereas TTP, DV, and MTT were significantly increased in cirrhosis ( P = 0.0006-0.0154). There was no correlation between IVIM- and DCE-MRI parameters. The highest Az (areas under the curves) values were observed for ADC (0.808) and TTP-DV (0.952 for each). The combination of ADC with DV and TTP provided 84.6% sensitivity and 100% specificity for diagnosis of cirrhosis. Conclusion: The combination of DW-MRI and DCE-MRI provides an accurate diagnosis of cirrhosis. J. Magn. Reson. Imaging 2010;31:589-600. © 2010 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

Purpose To investigate hepatic ischemia reperfusion injury (IRI) using diffusion tensor imaging (DTI). Materials and Methods Ten Sprague-Dawley rats were scanned at 7 Tesla (T) with DTI using b-value of 1000 s/mm2 and 6 gradient directions before, 2 h, and 1 day after 30-min total hepatic IRI. Apparent diffusion coefficient or mean diffusivity (MD), directional diffusivities and fractional anisotropy (FA) were measured. Seven of the animals were also examined with spin-echo echo-planar diffusion-weighted imaging (DWI) with seven b-values up to 2000 s/mm2 to estimate the true diffusion coefficient (D), blood pseudodiffusion coefficient (D*), and perfusion fraction (f) using a bi-compartmental model. Results MD 2 h after IRI (0.77 ± 0.07 × 10−3 mm2/s) was significantly lower ( P < 0.01) than that before (1.03 ± 0.07 × 10−3 mm2/s) and 1 day after IRI (1.01 ± 0.05 × 10−3 mm2/s). Meanwhile, FA 2 h after IRI (0.33 ± 0.03) was significantly higher ( P < 0.01) than that before (0.21 ± 0.02) and 1 day after IRI (0.20 ± 0.02). The bi-compartmental model analysis revealed the transient decrease in D, D* and f 2 h after IRI. Liver histology showed the multifocal cell swelling 3 h after IRI and widespread cell necrosis/apoptosis 1 day after IRI. Sinusoidal narrowing and congestion of erythrocytes were also observed 3 h and 1 day after IRI. Conclusion DTI can characterize hepatic IRI by detecting the transient change in both MD and FA. J. Magn. Reson. Imaging 2009;30:890-895. © 2009 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

Purpose To compare a free breathing navigator triggered single shot echoplanar imaging (SS EPI) diffusion-weighted imaging (DWI) sequence with prospective acquisition correction (PACE) with a breathhold (BH) DWI sequence for liver imaging. Materials and Methods Thirty-four patients were evaluated with PACE-DWI and BH DWI of the liver using b-values of 0, 50, and 500 s/mm2. There were 29 focal liver lesions in 18 patients. Qualitative evaluation was performed on a 3-point scale () by two independent observers (maximum score 9). Quantitative evaluation included estimated SNR (signal to noise ratio), lesion-to-liver contrast ratio, liver and lesion apparent diffusion coefficients (ADCs), and coefficient of variation (CV) of ADC in liver parenchyma and focal liver lesions (estimate of noise contamination in ADC). Results PACE-DWI showed significantly better image quality, higher SNR and lesion-to-liver contrast ratio when compared with BH DWI. ADCs of liver and focal lesions with both sequences were significantly correlated (r = 0.838 for liver parenchyma, and 0.904 for lesions, P < 0.0001), but lower with the BH sequence ( P < 0.02). There was higher noise contamination in ADC measurement obtained with BH DWI (with a significantly higher SD and CV of ADC). Conclusion The use of a navigator echo to trigger SS EPI DWI improves image quality and liver to lesion contrast, and enables a more precise ADC quantification compared with BH DWI acquisition. J. Magn. Reson. Imaging 2009;30:561-568. © 2009 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

Purpose To identify changes in vascular morphology on magnetic resonance imaging (MRI) in patients with cirrhosis and to compare these findings to liver donors. Materials and Methods Patients undergoing liver transplantation with biopsy-proven cirrhosis ( n = 74) and liver donor candidates ( n = 85) underwent dynamic gadolinium-enhanced 3D MR at 1.5T. Vessel diameters were measured independently by three radiologists and features of cirrhosis were identified and correlated with cirrhosis. Results Hepatic veins were smaller in patients with cirrhosis (4.9, 4.5, and 5.0 mm for right, middle, and left vs. 9.9, 7.6, and 8.9 mm in donors, P ≪ 0.001) and were negatively correlated with cirrhosis ( P < 0.001). Right hepatic vein (RHV) <5 mm diagnosed cirrhosis with 59% sensitivity and 99% specificity; the sensitivity and specificity were 88% and 85% for RHV <7 mm. Main portal vein was minimally larger in cirrhosis, 14 versus 12 mm ( P < 0.001) in donors. Right portal veins were smaller in cirrhotic patients, 6.5 and 6.2 mm compared to 8.4 and 7.6 mm ( P ≪ 0.001), respectively, in donors. Conclusion Vascular features of cirrhosis include small hepatic veins, minimally enlarged main portal vein, and small intrahepatic portal veins; these features may facilitate identification of cirrhosis. J. Magn. Reson. Imaging 2009;29:1085-1092. © 2009 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

Purpose To compare and determine the reproducibility of apparent diffusion coefficient (ADC) measurements of the normal liver parenchyma in breathhold, respiratory triggered, and free-breathing diffusion-weighted magnetic resonance imaging (DWI). Materials and Methods Eleven healthy volunteers underwent three series of DWI. Each DWI series consisted of one breathhold, one respiratory triggered, and two free-breathing (thick and thin slice acquisition) scans of the liver, at b-values of 0 and 500 s/mm2. ADCs of the liver parenchyma were compared by using nonparametric tests. Reproducibility was assessed by the Bland-Altman method. Results Mean ADCs (in 10−3 mm2/sec) in respiratory triggered DWI (2.07-2.27) were significantly higher than mean ADCs in breathhold DWI (1.57-1.62), thick slice free-breathing DWI (1.62-1.65), and thin slice free-breathing DWI (1.57-1.66) ( P < 0.005). Ranges of mean difference in ADC measurement ± limits of agreement between two scans were −0.02-0.05 ± 0.16-0.24 in breathhold DWI, −0.14-0.20 ± 0.59-0.60 in respiratory triggered DWI, −0.03-0.03 ± 0.20-0.29 in thick slice free-breathing DWI, and −0.01-0.09 ± 0.21-0.29 in thin slice free-breathing DWI. Conclusion ADC measurements of the normal liver parenchyma in respiratory triggered DWI are significantly higher and less reproducible than in breathhold and free-breathing DWI. J. Magn. Reson. Imaging 2008;28:1141-1148. © 2008 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

Purpose To investigate the relevance of increasing b-values in evaluating liver fibrosis through the agreement of two diffusion-weighted (DW) sequences. Materials and Methods A total of 29 cirrhotic patients and 29 healthy volunteers were studied on a 1.5T system. Two single-shot spin-echo echo-planar sequences were acquired using sets of increasing b-values: 0, 150, 250, and 400 seconds/mm2 (first sequence: DW1a) and 0, 150, 250, 400, 600, and 800 seconds/mm2 (second sequence: DW2a). Apparent diffusion coefficients (ADCs) of the hepatic parenchyma were calculated on ADC maps. Noise-scaled single-point ADCs were calculated for each sequence from b = 400 seconds/mm2. Results ADCs resulted significantly lower in cirrhotic patients compared to controls using both DW1a (mean 1.14 ± 0.20 × 10−3mm2/second vs. 1.54 ± 0.12 × 10−3mm2/second; P < 0.0001) and DW2a (mean 0.91 ± 0.18 × 10−3mm2/second vs. 1.04 ± 0.18 × 10−3mm2/second; P = 0.0089). DW1 and DW2, respectively significantly differed in diagnostic performance at receiver operating characteristic (ROC) curve analysis ( P = 0.003), showing AUCs of 0.93 (sensitivity 89.7%, specificity 100%) and 0.73 (sensitivity 62.1%, specificity 79.3%), respectively. Noise-scaled single-point ADCs showed a progressive convergence to similar values in cirrhotic and healthy livers at b = 800 seconds/mm2 (1.12 ± 0.27 × 10−3mm2/second vs. 1.13 ± 0.17 × 10−3mm2/second). Conclusion A DW sequence is accurate in assessing liver fibrosis using intermediate (400 seconds/mm2) rather than high (800 seconds/mm2) maximum b-values, but after proper recalculation of ADCs the effects of perfusion rather than diffusion should be considered responsible for the higher accuracy at lower b-values. J. Magn. Reson. Imaging 2008;28:411-419. © 2008 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

Level Of Evidence: 5 TECHNICAL EFFICACY STAGE: 2 J. Magn. Reson. Imaging 2020;52:805-806. [ABSTRACT FROM AUTHOR]

Contrast-enhanced body magnetic resonance imaging (MRI) requires high spatial resolution for optimal diagnostic assessment of angiographic and arterial phases with robust fat suppression and minimal motion artifacts. Differential subsampling with Cartesian ordering (DISCO) is a new spatiotemporal resolution dynamic contrast-enhanced MRI technique, which has been recently introduced to capture the enhancement dynamics of tumors and vascular structures at high resolution. Improved display of hepatic arterial anatomy using differential subsampling with Cartesian ordering (DISCO) with gadoxetic acid-enhanced MRI: Comparison with single arterial phase MRI and computed tomographic angiography. [Extracted from the article]

Level of Evidence: 5 Technical Efficacy Stage: 5 J. Magn. Reson. Imaging 2020;51:1568–1569. [ABSTRACT FROM AUTHOR]

Interobserver Agreement of PI-RADS v. 2: Not All Features or Observers Are Created Equal In 2014, the Prostate Imaging and Data Reporting System v. 2 (PI-RADSv2) was released.[1] PI-RADSv2 aimed to simplify the interpretation and reporting of prostate magnetic resonance imaging (MRI) and, in doing so, improve interobserver agreement between radiologists. In this issue of I The Journal of Magnetic Resonance Imaging i , Mussi et al sought to answer this question by comparing interobserver agreement levels across a group of eight radiologists with varying experience in prostate MRI when applying PI-RADSv2.[4]. [Extracted from the article]