Utility of a 2D kinematic HASTE sequence in magnetic resonance imaging assessment of adjacent segment degeneration following anterior cervical discectomy and fusion.

OBJECTIVES: To evaluate a dynamic half-Fourier acquired single turbo spin echo (HASTE) sequence following anterior cervical discectomy and fusion (ACDF) at the junctional level for adjacent segment degeneration comparing dynamic listhesis to radiographs and assessing dynamic cord contact and deformity during flexion-extension METHODS: Patients with ACDF referred for cervical spine MRI underwent a kinematic flexion-extension sagittal 2D HASTE sequence in addition to routine sequences. Images were independently reviewed by three radiologists for static/dynamic listhesis, and compared to flexion-extension radiographs. Blinded assessment of the HASTE sequence was performed for cord contact/deformity between neutral, flexion, and extension, to evaluate concordance between readers and inter-modality agreement. Inter-reader agreement for dynamic listhesis and impingement grade and inter-modality agreement for dynamic listhesis on MRI and radiographs was assessed using the kappa coefficient and percentage concordance. RESULTS: A total of 28 patients, mean age 60.2 years, were included. Mean HASTE acquisition time was 42 s. 14.3% demonstrated high grade dynamic stenosis (> grade 4) at the adjacent segment. There was substantial agreement for dynamic cord impingement with 70.2% concordance (kappa = 0.62). Concordance across readers for dynamic listhesis using HASTE was 81.0% (68/84) (kappa = 0.16) compared with 71.4% (60/84) (kappa = 0.40) for radiographs. Inter-modality agreement between flexion-extension radiographs and MRI assessment for dynamic listhesis across the readers was moderate (kappa = 0.41; 95% confidence interval: 0.16 to 0.67). CONCLUSIONS: A sagittal flexion-extension HASTE cine sequence provides substantial agreement between readers for dynamic cord deformity and moderate agreement between radiographs and MRI for dynamic listhesis. CLINICAL RELEVANCE STATEMENT: Degeneration of the adjacent segment with instability and myelopathy is one of the most common causes of pain and neurological deterioration requiring re-operation following cervical fusion surgery. KEY POINTS: • A real-time kinematic 2D sagittal HASTE flexion-extension sequence can be used to assess for dynamic listhesis, cervical cord, contact and deformity. • The additional kinematic cine sequence was well tolerated and the mean acquisition time for the 2D HASTE sequence was 42 s (range 31-44 s). • A sagittal flexion-extension HASTE cine sequence provides substantial agreement between readers for dynamic cord deformity and moderate agreement between radiographs and MRI for dynamic listhesis.

Male Breast Cancer Risk Assessment and Screening Recommendations in High-Risk Men Who Undergo Genetic Counseling and Multigene Panel Testing.

BACKGROUND: Emerging data suggest screening mammography may be effective in detecting breast cancer early in high-risk men. We evaluated current screening recommendations as a risk management strategy in men at elevated risk for breast cancer. PATIENTS AND METHODS: This institutional review board-approved, Health Insurance Portability and Accountability Act (HIPAA)-compliant study reviewed consecutive men who underwent genetic counseling and multigene panel testing (MGPT) for breast cancer risk assessment at our institution between 2012 and 2018. Patient risk factors, test indications, and MGPT outcomes were recorded, then correlated with screening recommendations by either clinical breast examination or screening mammography. Recommendation consistency among practitioners was evaluated. Patient adherence to screening mammography (defined as undergoing screening mammography as recommended) was assessed. Statistical analysis was performed at the 2-sided 5% significance level. RESULTS: A total of 414 asymptomatic men underwent both genetic counseling and MGPT (mean age, 47 years; range, 18-91 years) for breast cancer risk assessment. Of this group, 18 (4.3%) of 414 had a personal history of breast cancer, and 159 (38.4%) of 414 had a family history of breast cancer before MGPT. Among 112 men with positive MGPT results, BRCA1/2 mutations were the most common (56.3%, 63/112). Most BRCA mutation carriers (80.9%, 51/63) were recommended clinical breast examination only. Only 5.9% (2/34) BRCA2 and 10.3% (3/29) BRCA1 carriers were recommended screening mammograms (7.9%, 5/63 of all BRCA carriers). Among men with a personal history of breast cancer, only 9 (50%) of 18 were recommended screening mammograms. Overall adherence to screening mammogram in men was 71.4% (10/14), which ultimately yielded two cancers. Breast cancer screening recommendations varied widely among practitioners, with some recommending clinical breast examination only, and others also recommending mammography. CONCLUSION: Men who are found to be at an elevated risk for breast cancer after undergoing genetic counseling and testing currently receive relatively inconsistent screening recommendations.

Clinical feasibility of 2D dynamic sagittal HASTE flexion-extension imaging of the cervical spine for the assessment of spondylolisthesis and cervical cord impingement.

PURPOSE: To assess the utility of a 2D dynamic HASTE sequence in assessment of cervical spine flexion-extension, specifically (1) comparing dynamic spondylolisthesis to radiographs and (2) assessing dynamic contact upon or deformity of the cord. METHODS: Patients with a dynamic flexion-extension sagittal 2D HASTE sequence in addition to routine cervical spine sequences were identified. Static and dynamic listhesis was first determined on flexion-extension radiographs reviewed in consensus. Blinded assessment of the dynamic HASTE sequence was independently performed by 2 radiologists for (1) listhesis and translation during flexion-extension and (2) dynamic spinal cord impingement (cord contact or deformity between neutral, flexion and extension). RESULTS: 32 scans in 32 patients (9 males, 23 females) met inclusion criteria acquired on 1.5 T (n = 15) and 3 T (n = 17) scanners. The mean acquisition time was 51.8 s (range 20-95 seconds). Dynamic translation was seen in 14 patients on flexion-extension radiographs compared to 12 (reader 1) and 13 (reader 2) patients on HASTE, with 90.6 % agreement (K = 0.83; p = 0.789). In all cases dynamic listhesis was ≤3 mm translation with one patient showing dynamic listhesis in the range 4-6 mm. Four cases (13 %) demonstrated deformity of the cord between flexion-extension, not present in the neutral position. For cord impingement there was strong inter-reader agreement (K = 0.93) and the paired sample Wilcoxon signed rank test found no significant difference between the impingement scores of the two readers (p = 0.787). CONCLUSIONS: A sagittal dynamic flexion-extension HASTE sequence provides a rapid addition to standard MRI cervical spine protocols, which may useful for assessment of dynamic spondylolisthesis and cord deformity.

Gadoxetate disodium-enhanced MRI: Assessment of arterial phase artifacts and hepatobiliary uptake in a large series.

PURPOSE: To report the quality of gadoxetate disodium MRI in a large series by assessing the prevalence of: 1) arterial phase (AP) artifacts and its predictive factors, 2) decreased hepatic contrast uptake during the hepatobiliary phase (HBP). METHODS: This retrospective single center study included 851 patients (M/F:537/314, mean age: 63y) with gadoxetate disodium MRI. The MRI protocol included unenhanced, dual arterial [early and late arterial phases (AP)], portal venous, transitional and hepatobiliary phases. Three radiologists graded dynamic images using a 5-scale score (1: no motion, 5: severe, nondiagnostic) for assessment of transient severe motion (TSM, defined as a score ≥4 during at least one AP with a score ≤3 during other phases). HBP uptake was assessed using a 3-scale score (based on portal vein/hepatic signal). The association between demographic, clinical and acquisition parameters with TSM was tested in uni- and multivariate logistic regression. RESULTS: TSM was observed in 103/851 patients (12.1 %): 83 (9.8 %) in one AP and 20 (2.3 %) in both APs. A score of 5 (nondiagnostic) was assigned in 7 patients in one AP (0.8 %) and none in both. Presence of TSM was significantly associated with age (p = 0.002) and liver disease (p = 0.033) in univariate but not in multivariate analysis (p > 0.05). No association was found between acquisition parameters and TSM occurrence. Limited or severely limited HBP contrast uptake was observed in 87 patients (10.2 %), and TSM was never associated with severely limited HBP contrast uptake. CONCLUSION: TSM was present in approximately 12 % of gadoxetate disodium MRIs, rarely on both APs (2.3 %), and was poorly predicted. TSM was never associated with severely limited HBP contrast uptake.

Outcomes assessment in intrahepatic cholangiocarcinoma using qualitative and quantitative imaging features.

BACKGROUND: To assess the performance of imaging features, including radiomics texture features, in predicting histopathologic tumor grade, AJCC stage, and outcomes [time to recurrence (TTR) and overall survival (OS)] in patients with intrahepatic cholangiocarcinoma (ICC). METHODS: Seventy-three patients (26 M/47F, mean age 63y) with pre-operative imaging (CT, n = 37; MRI, n = 21; CT and MRI, n = 15] within 6 months of resection were included in this retrospective study. Qualitative imaging traits were assessed by 2 observers. A 3rd observer measured tumor apparent diffusion coefficient (ADC), enhancement ratios (ERs), and Haralick texture features. Blood biomarkers and imaging features were compared with histopathology (tumor grade and AJCC stage) and outcomes (TTR and OS) using log-rank, generalized Wilcoxon, Cox proportional hazards regression, and Fisher exact tests. RESULTS: Median TTR and OS were 53.9 and 79.7 months. ICC recurred in 64.4% (47/73) of patients and 46.6% (34/73) of patients died. There was fair accuracy for some qualitative imaging features in the prediction of worse tumor grade (maximal AUC of 0.68 for biliary obstruction on MRI, p = 0.032, observer 1) and higher AJCC stage (maximal AUC of 0.73 for biliary obstruction on CT, p = 0.002, observer 2; and AUC of 0.73 for vascular involvement on MRI, p = 0.01, observer 2). Cox proportional hazards regression analysis showed that CA 19-9 [hazard ratio (HR) 2.44/95% confidence interval (CI) 1.31-4.57/p = 0.005)] and tumor size on imaging (HR 1.13/95% CI 1.04-1.22/p = 0.003) were significant predictors of TTR, while CA 19-9 (HR 4.08/95% CI 1.75-9.56, p = 0.001) and presence of metastatic lymph nodes at histopathology (HR 2.86/95% CI 1.35-6.07/p = 0.006) were significant predictors of OS. On multivariable analysis, satellite lesions on CT (HR 2.79/95%CI 1.01-7.15/p = 0.032, observer 2), vascular involvement on MRI (HR 0.10/95% CI 0.01-0.85/p = 0.032, observer 1), and texture feature MRI variance (HR 0.55/95% CI 0.31-0.97, p = 0.040) predicted TTR once adjusted for the independent predictors CA 19-9 and tumor size on imaging. Several qualitative and quantitative features demonstrated associations with TTR, OS, and AJCC stage at univariable analysis (range: HR 0.35-19; p < 0.001-0.045), however none were predictive of OS at multivariable analysis when adjusted for CA 19-9 and metastatic lymph nodes (p > 0.088). CONCLUSIONS: There was reasonable accuracy in predicting tumor grade and higher AJCC stage in ICC utilizing certain qualitative and quantitative imaging traits. Serum CA 19-9, tumor size, presence of metastatic lymph nodes, and qualitative imaging traits of satellite lesions and vascular involvement are predictors of patient outcomes, along with a promising predictive ability of certain quantitative texture features.

Gadoxetate-enhanced abbreviated MRI is highly accurate for hepatocellular carcinoma screening.

OBJECTIVES: The primary objective was to compare the performance of 3 different abbreviated MRI (AMRI) sets extracted from a complete gadoxetate-enhanced MRI obtained for hepatocellular carcinoma (HCC) screening. Secondary objective was to perform a preliminary cost-effectiveness analysis, comparing each AMRI set to published ultrasound performance for HCC screening in the USA. METHODS: This retrospective study included 237 consecutive patients (M/F, 146/91; mean age, 58 years) with chronic liver disease who underwent a complete gadoxetate-enhanced MRI for HCC screening in 2017 in a single institution. Two radiologists independently reviewed 3 AMRI sets extracted from the complete exam: non-contrast (NC-AMRI: T2-weighted imaging (T2wi)+diffusion-weighted imaging (DWI)), dynamic-AMRI (Dyn-AMRI: T2wi+DWI+dynamic T1wi), and hepatobiliary phase AMRI (HBP-AMRI: T2wi+DWI+T1wi during the HBP). Each patient was classified as HCC-positive/HCC-negative based on the reference standard, which consisted in all available patient data. Diagnostic performance for HCC detection was compared between sets. Estimated set characteristics, including historical ultrasound data, were incorporated into a microsimulation model for cost-effectiveness analysis. RESULTS: The reference standard identified 13/237 patients with HCC (prevalence, 5.5%; mean size, 33.7 ± 30 mm). Pooled sensitivities were 61.5% for NC-AMRI (95% confidence intervals, 34.4-83%), 84.6% for Dyn-AMRI (60.8-95.1%), and 80.8% for HBP-AMRI (53.6-93.9%), without difference between sets (p range, 0.06-0.16). Pooled specificities were 95.5% (92.4-97.4%), 99.8% (98.4-100%), and 94.9% (91.6-96.9%), respectively, with a significant difference between Dyn-AMRI and the other sets (p < 0.01). All AMRI methods were effective compared with ultrasound, with life-year gain of 3-12 months against incremental costs of US$ < 12,000. CONCLUSIONS: NC-AMRI has limited sensitivity for HCC detection, while HBP-AMRI and Dyn-AMRI showed excellent sensitivity and specificity, the latter being slightly higher for Dyn-AMRI. Cost-effectiveness estimates showed that AMRI is effective compared with ultrasound. KEY POINTS: • Comparison of different abbreviated MRI (AMRI) sets reconstructed from a complete gadoxetate MRI demonstrated that non-contrast AMRI has low sensitivity (61.5%) compared with contrast-enhanced AMRI (80.8% for hepatobiliary phase AMRI and 84.6% for dynamic AMRI), with all sets having high specificity. • Non-contrast and hepatobiliary phase AMRI can be performed in less than 14 min (including set-up time), while dynamic AMRI can be performed in less than 17 min. • All AMRI sets were cost-effective for HCC screening in at-risk population in comparison with ultrasound.

City Patterns of Screening Mammography Uptake and Disparity across the United States.

Background Although previous studies have focused on rural disparities in the use of screening mammography, city-level use throughout the United States has not been well evaluated even though more than 30 million women live in the 500 largest cities. Purpose To evaluate disparities in the city-level use of screening mammography and to identify factors that have an impact on screening utilization. Materials and Methods This retrospective study used data from large publicly available databases, the American Community Survey and Robert Wood Johnson Foundation 500 Cities Project, which includes screening mammography utilization data from the Behavioral Risk Factor Surveillance System. Databases were searched from January to March 2018. The use of screening mammography was evaluated at the city level by census region and division by using the Mann-Whitney U test. Univariable Spearman rank correlation and multivariable regression analysis were performed to determine the impact of factors on screening use, including population size, health-related variables (use of Papanicolaou test, obesity), income variables (median household income, poverty status, health insurance), and race. Results Overall mean city-level screening mammography use rate was 77.7% (range, 62.8%-88.9%). The highest mean utilization occurred in coastal cities, with the highest overall utilization in the New England area (82.7%). The lowest utilization rate was in Mountain states (73.6%). City-level utilization showed a positive correlation with Papanicolaou test use (r = 0.75, P < .001), median household income (r = 0.44, P < .001), and percentage Asian population (r = 0.38, P < .001) and a negative correlation with obesity (r = -0.36, P < .001), the lack of health insurance (r = -0.44, P < .001), and poverty (r = -0.30, P < .001). Multivariable analysis showed the strongest independent predictors of utilization to be percentage of women screened with the Papanicolaou test, Asian race, private insurance, and census division (R2 = 68%). Conclusion Disparities in the utilization of preventive health care services exist at the large city level, with the highest use in New England cities and lowest in Mountain cities. Predictors of higher than average utilization include census division and percentage of inhabitants who are up to date with the Papanicolaou test, are of Asian race, and have private insurance. © RSNA, 2019.

Double Scan CT Rates: An Opportunity for Facility-Based Radiologist Measures in the Quality Payment Program.

PURPOSE: The Medicare Access and CHIP Reauthorization Act (MACRA) provides CMS flexibility to evaluate radiologists using hospital outpatient quality measures in place of conventional physician measures. We explore radiologist characteristics associated with variation in performance in two such measures: abdomen and chest CT "double scan" rates (percentage of total examinations performed both with and without intravenous contrast). METHODS: Radiologists' claims for abdomen and chest CT examinations in a facility setting were identified using 2014 Medicare Physician and Other Supplier data. Individual radiologist double scan rates were computed. Associations were explored between rates and radiologist characteristics extracted from the CMS public data sets using multivariable regression with cross-validation. RESULTS: Radiologists' double scan rates averaged 5.9% ± 10.0% (0.0% for 52.8% of radiologists) for abdomen CT (19,867 radiologists) and 1.0% ± 4.7% (0.0% for 91.3% of radiologists) for chest CT (18,684). At multivariable analysis, abdomen rates were best predicted by geography (lowest in Northeast, greatest in West), practice size (greatest for small practices), and specialty practice pattern (lowest for general radiologists; greatest for nuclear medicine physicians). Agreement for double scan rates among radiologists within the same practice was moderate, though slightly higher for chest (intraclass correlation = 0.70) than abdomen (0.59). CONCLUSION: Radiologists' facility double scan rates vary systematically based on an array of professional characteristics. MACRA grants CMS the authority to use these measures for evaluating radiologists, thereby aligning Medicare's hospital and physician performance programs and better incentivizing population radiation dose and cost reduction. Greater variation in abdomen CT double scan rates, compared with ubiquitously excellent chest CT performance, supports a particular role for abdomen rates in distinguishing disparities in radiologist performance.

Comparison between qualitative and quantitative assessment of background parenchymal enhancement on breast MRI.

BACKGROUND: Potential clinical implications of the level of background parenchymal enhancement (BPE) on breast MRI are increasing. Currently, BPE is typically evaluated subjectively. Tests of concordance between subjective BPE assessment and computer-assisted quantified BPE have not been reported. PURPOSE OR HYPOTHESIS: To compare subjective radiologist assessment of BPE with objective quantified parenchymal enhancement (QPE). STUDY TYPE: Cross-sectional observational study. POPULATION: Between 7/24/2015 and 11/27/2015, 104 sequential patients (ages 23 - 81 years, mean 49 years) without breast cancer underwent breast MRI and were included in this study. FIELD STRENGTH/SEQUENCE: 3T; fat suppressed axial T2, axial T1, and axial fat suppressed T1 before and after intravenous contrast. ASSESSMENT: Four breast imagers graded BPE at 90 and 180 s after contrast injection on a 4-point scale (a-d). Fibroglandular tissue masks were generated using a phantom-validated segmentation algorithm, and were co-registered to pre- and postcontrast fat suppressed images to define the region of interest. QPE was calculated. STATISTICAL TESTS: Receiver operating characteristic (ROC) analyses and kappa coefficients (k) were used to compare subjective BPE with QPE. RESULTS: ROC analyses indicated that subjective BPE at 90 s was best predicted by quantified QPE ≤20.2 = a, 20.3-25.2 = b, 25.3-50.0 = c, >50.0 = d, and at 180 s by quantified QPE ≤ 32.2 = a, 32.3-38.3 = b, 38.4-74.5 = c, >74.5 = d. Agreement between subjective BPE and QPE was slight to fair at 90 s (k = 0.20-0.36) and 180 s (k = 0.19-0.28). At higher levels of QPE, agreement between subjective BPE and QPE significantly decreased for all four radiologists at 90 s (P ≤ 0.004) and for three of four radiologists at 180 s (P ≤ 0.004). DATA CONCLUSION: Radiologists were less consistent with QPE as QPE increased. LEVEL OF EVIDENCE: 3 Technical Efficacy: Stage 3 J. Magn. Reson. Imaging 2018;47:1685-1691.

Screening Mammography Utilization and Medicare Beneficiaries' Perceptions of Their Primary Care Physicians.

RATIONALE AND OBJECTIVES: To assess associations between screening mammography utilization and Medicare beneficiaries' relationships with, and impressions of, their primary care physicians. MATERIALS AND METHODS: Using the Medicare Current Beneficiary Survey Access to Care Public Use File, we retrospectively studied responses from a national random cross section of Medicare beneficiaries surveyed in 2013 regarding perceptions of their primary care physicians and their screening mammography utilization. Statistical analysis accounted for subject weighting factors to estimate national screening utilization. RESULTS: Among 7492 female Medicare beneficiaries, 62.0% (95% confidence interval 59.8%-64.2%) underwent screening mammography. Utilization was higher for beneficiaries having (vs. not) a regular medical practice or clinic (63.2% vs. 34.6%) and a usual physician (63.8% vs. 50.3%). Utilization was higher for beneficiaries very satisfied (vs. very dissatisfied) with the overall quality of care they received (66.0% vs. 35.8%), their ease of getting to a doctor (67.7% vs. 43.2%), and their physician's concerns for their health (65.7% vs. 53.4%), as well as for beneficiaries strongly agreeing (vs. strongly disagreeing) that their physician is competent (66.0% vs. 54.1%), understands what is wrong (66.3% vs. 47.1%), answers all questions (67.0% vs. 46.7%), and fosters confidence (66.0% vs. 50.6%). Independent predictors of screening mammography utilization (P < .05) were satisfaction with quality of care, having a regular practice or clinic, and satisfaction with ease of getting to their physician. CONCLUSIONS: Screening mammography utilization is higher among Medicare beneficiaries with established primary physician relationships, particularly when those relationships are favorable. To optimize screening mammography utilization, breast imagers are encouraged to support initiatives to enhance high-quality primary care relationships.

Prostate Cancer: Diffusion-weighted MR Imaging for Detection and Assessment of Aggressiveness-Comparison between Conventional and Kurtosis Models.

Purpose To compare standard diffusion-weighted (DW) imaging and diffusion kurtosis (DK) imaging for prostate cancer (PC) detection and characterization in a large patient cohort, with attention to the potential added value of DK imaging. Materials and Methods This retrospective institutional review board-approved study received a waiver of informed consent. Two hundred eighty-five patients with PC underwent 3.0-T phased-array coil prostate magnetic resonance (MR) imaging, including a DK imaging sequence (b values 0, 500, 1000, 1500, and 2000 sec/mm2) before prostatectomy. Maps of apparent diffusion coefficient (ADC) and diffusional kurtosis (K) were derived by using maximal b values of 1000 and 2000 sec/mm2, respectively. Mean ADC and K were obtained from volumes of interest (VOIs) placed on each patient's dominant tumor and benign prostate tissue. Metrics were compared between benign and malignant tissue, between Gleason score (GS) ≤ 3 + 3 and GS ≥ 3 + 4 tumors, and between GS ≤ 3 + 4 and GS ≥ 4 + 3 tumors by using paired t tests, analysis of variance, receiver operating characteristic (ROC) analysis, and exact tests. Results ADC and K showed significant differences for benign versus tumor tissues, GS ≤ 3 + 3 versus GS ≥ 3 + 4 tumors, and GS ≤ 3 + 4 versus GS ≥ 4 + 3 tumors (P < .001 for all). ADC and K were highly correlated (r = -0.82; P < .001). Area under the ROC curve was significantly higher (P = .002) for ADC (0.921) than for K (0.902) for benign versus malignant tissue but was similar for GS ≤ 3 + 3 versus GS ≥ 3 + 4 tumors (0.715-0.744) and GS ≤ 3 + 4 versus GS ≥ 4 + 3 tumors (0.694-0.720) (P > .15). ADC and K were concordant for these various outcomes in 80.0%-88.6% of patients; among patients with discordant results, ADC showed better performance than K for GS ≤ 3 + 4 versus GS ≥ 4 + 3 tumors (P = .016) and was similar to K for other outcomes (P > .136). Conclusion ADC and K were highly correlated, had similar diagnostic performance, and were concordant for the various outcomes in the large majority of cases. These observations did not show a clear added value of DK imaging compared with standard DW imaging for clinical PC evaluation. © RSNA, 2017 Online supplemental material is available for this article.

Assessment of prostate cancer aggressiveness using apparent diffusion coefficient values: impact of patient race and age.

PURPOSE: To assess the impact of patient race and age on the performance of apparent diffusion coefficient (ADC) values for assessment of prostate cancer aggressiveness. MATERIALS AND METHODS: 457 prostate cancer patients who underwent 3T phased-array coil prostate MRI including diffusion-weighted imaging (DWI; maximal b-value 1000 s/mm2) before prostatectomy were included. Mean ADC of a single dominant lesion was measured in each patient, using histopathologic findings from the prostatectomy specimen as reference. In subsets defined by race and age, ADC values were compared between Gleason score (GS) ≤ 3 + 4 and GS ≥ 4 + 3 tumors. RESULTS: 81% of patients were Caucasian, 12% African-American, 7% Asian-American. 13% were <55 years, 42% 55-64 years, 41% 65-74 years, and 4% ≥75 years. 63% were GS ≤ 3 + 4, 37% GS ≥ 4 + 3. ADC was significantly lower in GS ≥ 4 + 3 tumors than in GS ≤ 3 + 4 tumors in the entire cohort, as well as in Caucasian, African-American, and all four age groups (P ≤ 0.015). AUC for differentiation of GS ≤ 3 + 4 and GS ≥ 4 + 3 as well as optimal ADC threshold was Caucasian: 0.73/≤848; African-American: 0.76/≤780; Asian-American: 0.66/≤839: <55 years, 0.73/≤830; 55-64 years, 0.71/≤800; 65-74 years, 0.74/≤872; ≥75 years, 0.79/≤880. A race-optimized ADC threshold resulted in higher specificity in African-American than Caucasian men (84.9% vs. 67.1%, P = 0.045); age-optimized ADC threshold resulted in higher sensitivity in patients aged ≥75 years than <55 years or 55-64 years (100.0% vs. 53.6%-73.3%; P < 0.001). CONCLUSION: Patients' race and age may impact the diagnostic performance and optimal threshold when applying ADC values for evaluation of prostate cancer aggressiveness.

A low-cost Mr compatible ergometer to assess post-exercise phosphocreatine recovery kinetics.

OBJECTIVE: To develop a low-cost pedal ergometer compatible with ultrahigh (7 T) field MR systems to reliably quantify metabolic parameters in human lower leg muscle using phosphorus magnetic resonance spectroscopy. MATERIALS AND METHODS: We constructed an MR compatible ergometer using commercially available materials and elastic bands that provide resistance to movement. We recruited ten healthy subjects (eight men and two women, mean age ± standard deviation: 32.8 ± 6.0 years, BMI: 24.1 ± 3.9 kg/m2). All subjects were scanned on a 7 T whole-body magnet. Each subject was scanned on two visits and performed a 90 s plantar flexion exercise at 40% maximum voluntary contraction during each scan. During the first visit, each subject performed the exercise twice in order for us to estimate the intra-exam repeatability, and once during the second visit in order to estimate the inter-exam repeatability of the time constant of phosphocreatine recovery kinetics. We assessed the intra and inter-exam reliability in terms of the within-subject coefficient of variation (CV). RESULTS: We acquired reliable measurements of PCr recovery kinetics with an intra- and inter-exam CV of 7.9% and 5.7%, respectively. CONCLUSION: We constructed a low-cost pedal ergometer compatible with ultrahigh (7 T) field MR systems, which allowed us to quantify reliably PCr recovery kinetics in lower leg muscle using 31P-MRS.

Dynamic contrast-enhanced MRI of the prostate: An intraindividual assessment of the effect of temporal resolution on qualitative detection and quantitative analysis of histopathologically proven prostate cancer.

PURPOSE: To assess the effects of temporal resolution (RT ) in dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) on qualitative tumor detection and quantitative pharmacokinetic parameters in prostate cancer. MATERIALS AND METHODS: This retrospective Institutional Review Board (IRB)-approved study included 58 men (64 ± 7 years). They underwent 3T prostate MRI showing dominant peripheral zone (PZ) tumors (24 with Gleason ≥ 4 + 3), prior to prostatectomy. Continuously acquired DCE utilizing GRASP (Golden-angle RAdial Sparse Parallel) was retrospectively reconstructed at RT of 1.4 sec, 3.7 sec, 6.0 sec, 9.7 sec, and 14.9 sec. A reader placed volumes-of-interest on dominant tumors and benign PZ, generating quantitative pharmacokinetic parameters (ktrans , ve ) at each RT . Two blinded readers assessed each RT for lesion presence, location, conspicuity, and reader confidence on a 5-point scale. Data were assessed by mixed-model analysis of variance (ANOVA), generalized estimating equation (GEE), and receiver operating characteristic (ROC) analysis. RESULTS: RT did not affect sensitivity (R1all : 69.0%-72.4%, all Padj = 1.000; R1GS≥4 + 3 : 83.3-91.7%, all Padj = 1.000; R2all : 60.3-69.0%, all Padj = 1.000; R2GS≥4 + 3 : 58.3%-79.2%, all Padj = 1.000). R1 reported greater conspicuity of GS ≥ 4 + 3 tumors at RT of 1.4 sec vs. 14.9 sec (4.29 ± 1.23 vs. 3.46 ± 1.44; Padj = 0.029). No other tumor conspicuity pairwise comparison reached significance (R1all : 2.98-3.43, all Padj ≥ 0.205; R2all : 2.57-3.19, all Padj ≥ 0.059; R1GS≥4 + 3 : 3.46-4.29, all other Padj ≥ 0.156; R2GS≥4 + 3 : 2.92-3.71, all Padj ≥ 0.439). There was no effect of RT on reader confidence (R1all : 3.17-3.34, all Padj = 1.000; R2all : 2.83-3.19, all Padj ≥ 0.801; R1GS≥4 + 3 : 3.79-4.21, all Padj = 1.000; R2GS≥4 + 3 : 3.13-3.79, all Padj = 1.000). ktrans and ve of tumor and benign tissue did not differ across RT (all adjusted P values [Padj ] = 1.000). RT did not significantly affect area under the curve (AUC) of Ktrans or ve for differentiating tumor from benign (all Padj = 1.000). CONCLUSION: Current PI-RADS recommendations for RT of 10 seconds may be sufficient, with further reduction to the stated PI-RADS preference of RT ≤ 7 seconds offering no benefit in tumor detection or quantitative analysis. LEVEL OF EVIDENCE: 3 J. MAGN. RESON. IMAGING 2017;45:1464-1475.

Assessment of Background Parenchymal Enhancement and Lesion Kinetics in Breast MRI of BRCA 1/2 Mutation Carriers Compared to Matched Controls Using Quantitative Kinetic Analysis.

RATIONALE AND OBJECTIVES: To investigate whether quantitative kinetic analysis of lesions and background parenchyma in breast magnetic resonance imaging can elucidate differences between BRCA carriers and sporadic controls with high risk for breast cancer. MATERIALS AND METHODS: Fifty-nine BRCA and 59 control cases (49 benign, 10 malignant) were examined in this study. Principal component analysis was applied for quantitative analysis of dynamic signal in background parenchyma (B) and lesion (L) in terms of initial enhancement ratio (IER) and delayed enhancement ratio (DER). RESULTS: Control B-IER, B-DER, L-IER, and L-DER were higher than BRCA cases in all women and in women with benign lesions; statistically significant differences in B-IER and B-DER (all women: P = 0.02 and P = 0.02, respectively; benign only: P = 0.005 and P = 0.005, respectively). In the control cohort, B-IER and B-DER were higher in the premenopausal women than in the postmenopausal women (P = 0.013 and 0.003, respectively), but not in the BRCA cohort; this led to significant differences in B-IER and B-DER between the control and the BRCA groups in the premenopausal women (P = 0.01 and 0.01, respectively) but not in the postmenopausal women. CONCLUSION: Results suggest possible differences in the vascular properties of background parenchyma between BRCA carriers and noncarriers and its association with menopausal status.

Length of capsular contact for diagnosing extraprostatic extension on prostate MRI: Assessment at an optimal threshold.

PURPOSE: To evaluate the length of capsular contact of dominant lesions on multiparametric prostate magnetic resonance imaging (MRI) for predicting extraprostatic extension (EPE) and to determine a threshold value to apply in clinical practice. MATERIALS AND METHODS: Ninety patients undergoing 3T prostate MRI before prostatectomy were included. Two independent readers (R1, R2) recorded for each lobe the presence or absence of capsular irregularity on T2 -weighted imaging (T2 WI) and of overt measurable EPE. Readers also recorded the length of capsular contact of each lobe's dominant lesion for T2 WI and the apparent diffusion coefficient (ADC) map. Based on prostatectomy specimens, EPE was recorded for each lobe and classified as focal (single focus ≤0.5 mm in depth) vs. established. Receiver operating characteristic analysis, logistic regression, and kappa coefficients were used to assess interpretive approaches on a side-specific basis. RESULTS: The optimal thresholds were 6 mm and 7 mm of contact using T2 WI and ADC for any EPE, and 10 mm and 7 mm using T2 WI and ADC for nonfocal EPE (AUCs 81.0-82.5%). Capsular contact had higher sensitivity, yet lower specificity, than subjective interpretations for any EPE and for nonfocal EPE (all P ≤ 0.018, aside from any EPE for R2 using ADC). Length of contact exhibited more substantial gains in sensitivity (9-20% for any EPE; 34-41% for nonfocal EPE) than losses in specificity (6-13% for any EPE; 17-27% for nonfocal EPE) compared with subjective interpretations. Interreader agreement: 0.70 for assessments based on length of contact; 0.49-0.59 for subjective assessments. CONCLUSION: Length of capsular contact of dominant lesions can improve interreader agreement and sensitivity for EPE compared with subjective features, with relatively mild specificity loss.

T2-weighted imaging of the prostate: Impact of the BLADE technique on image quality and tumor assessment.

PURPOSE: To retrospectively compare standard and BLADE T2-weighted imaging (T2WI) sequences of the prostate in terms of image quality and tumor assessment. METHODS: 49 prostate cancer patients (64 ± 6 years) who underwent 3 T phased-array coil MRI before prostatectomy were included. T2WI was acquired using standard rectilinear and BLADE techniques. Two readers (R1, R2) independently localized the dominant lesion using T2WI alone and using multi-parametric imaging; recorded presence of extraprostatic extension (EPE) in each lobe; and scored lesion conspicuity and absence of motion artifact (1-5 scale; 5 = highest quality). A third reader, unblinded to pathology, placed ROIs to record tumor-to-peripheral-zone contrast. Standard and BLADE T2WI were compared using paired Wilcoxon tests. RESULTS: BLADE showed a trend toward improved motion artifact for R1 (3.4 ± 1.3 vs. 2.9 ± 1.5; p = 0.054) but not R2 (4.0 ± 1.0 vs. 3.9 ± 1.1; p = 0.880). Dominant lesions showed significantly lower conspicuity using BLADE for R1 (2.8 ± 2.0 vs. 3.2 ± 2.0; p = 0.011) but not R2 (2.3 ± 1.6 vs. 2.4 ± 1.7; p = 0.353), and significantly lower tumor-to-peripheral-zone contrast using BLADE (0.35 ± 0.13 vs. 0.42 ± 0.15; p ≤ 0.001). R1 and R2 correctly localized four and three fewer dominant tumors, respectively, using BLADE than standard T2WI, although both correctly localized a similar fraction of dominant tumors using multi-parametric sequences. While R1 detected EPE in 10 of 11 patients using both sequences, R2 detected EPE in 3 more patients using BLADE. CONCLUSION: BLADE may help reduce motion artifact of prostate T2WI and assist EPE detection, although at expense of reduced image contrast. In practice, BLADE may be useful in patients in whom initial T2WI is degraded by motion.

Non-Gaussian diffusion MRI assessment of brain microstructure in mild cognitive impairment and Alzheimer's disease.

We report the first application of a novel diffusion-based MRI method, called diffusional kurtosis imaging (DKI), to investigate changes in brain tissue microstructure in patients with mild cognitive impairment (MCI) and AD and in cognitively intact controls. The subject groups were characterized and compared in terms of DKI-derived metrics for selected brain regions using analysis of covariance with a Tukey multiple comparison correction. Receiver operating characteristic (ROC) and binary logistic regression analyses were used to assess the utility of regional diffusion measures, alone and in combination, to discriminate each pair of subject groups. ROC analyses identified mean and radial kurtoses in the anterior corona radiata as the best individual discriminators of MCI from controls, with the measures having an area under the ROC curve (AUC) of 0.80 and 0.82, respectively. The next best discriminators of MCI from controls were diffusivity and kurtosis (both mean and radial) in the prefrontal white matter (WM), with each measure having an AUC between 0.77 and 0.79. Finally, the axial diffusivity in the hippocampus was the best overall discriminator of MCI from AD, having an AUC of 0.90. These preliminary results suggest that non-Gaussian diffusion MRI may be beneficial in the assessment of microstructural tissue damage at the early stage of MCI and may be useful in developing biomarkers for the clinical staging of AD.

Serial diffusion-weighted MRI in patients with hepatocellular carcinoma: Prediction and assessment of response to transarterial chemoembolization. Preliminary experience.

OBJECTIVE: To assess the role of apparent diffusion coefficient (ADC) measured with diffusion-weighted imaging (DWI) in predicting and assessing response of hepatocellular carcinoma (HCC) to transarterial chemoembolization (TACE). METHODS: Thirty-six patients with cirrhosis and untreated HCC who underwent TACE and MRI within 3 months before and after TACE were assessed. MRI included DWI and contrast-enhanced T1-weighted imaging. Two observers measured ADC of HCCs and liver parenchyma on pre- and post-TACE MRIs and measured degree of tumor necrosis on subtracted post-contrast images on post-TACE MRI. Pre-, post-TACE tumor ADC, and changes in tumor ADC (ΔADC) were compared between lesions stratified by degree of tumor necrosis (measured on post-TACE MRI). RESULTS: Forty seven HCCs were evaluated (mean size 4.4cm, range 1.0-14.1cm). HCCs with poor and incomplete response to TACE (<50% necrosis on post-TACE MRI) had significantly lower pre-treatment ADC and lower post TACE ADC compared to HCCs with good/complete response (≥50% necrosis): ADC pre-TACE 1.35±0.42 vs. 1.64±0.39×10(-3)mm(2)/s (p=0.042); post-TACE ADC 1.34±0.36 vs. 1.92±0.47 (p=0.0008). There was no difference in ΔADC values. CONCLUSION: This preliminary data suggests that pre-TACE tumor ADC can be used to predict HCC response to TACE.