Histogram Analysis of Native T1 Mapping and Its Relationship to Left Ventricular Late Gadolinium Enhancement, Hypertrophy, and Segmental Myocardial Mechanics in Patients With Hypertrophic Cardiomyopathy.

BACKGROUND: The use of native T1 mapping for evaluation of hypertrophic cardiomyopathy (HCM) is being explored, and its combination with histogram analysis may benefit the accuracy of such assessments. PURPOSE: To investigate the relationship of segmental left ventricular wall thickness (LVWT), myocardial fibrosis, and strain parameters with segmental histogram parameters of native T1 mapping in HCM patients. STUDY TYPE: Retrospective. SUBJECTS: Ninety-three HCM patients without previous cardiovascular diseases were included. FIELD STRENGTH/SEQUENCE: 3.0T cardiac MR. Steady-state free precession cine imaging, modified Look-Locker inversion recovery, phase-sensitive inversion recovery. ASSESSMENT: Images were assessed by three experienced radiologists. STATISTICAL TESTS: Mann-Whitney U-tests, area under the curve (AUC), Spearman's rank correlation, intraclass correlation coefficient, and Bland-Altman test were used for statistical analysis. RESULTS: A higher LVWT value correlated with higher means, minimums, 10th /25th /50th /75th /90th percentiles, maximums, kurtosis, entropy, and lower SD and energy of T1 mapping (P < 0.05 for all), with the correlation being stronger for entropy and energy (Spearman's rho = 0.439 and -0.413, respectively) than other parameters. Late gadolinium enhancement positive (LGE+) segments exhibited higher mean, minimum, 10th /25th /50th /75th /90th percentiles, maximum, entropy, and lower energy of T1 times than late gadolinium enhancement negative (LGE-) segments (P < 0.001 for all). Impaired strain function parameters (peak thickening and thickening rate in radial, circumferential, and longitudinal directions) demonstrated a weak correlation with higher entropy (P < 0.001 for all) and lower energy (P < 0.001 for all). DATA CONCLUSION: Histogram parameters of native T1 mapping provide more information than mean T1 times alone. Among these parameters, entropy and energy may correlate better with LVWT, myocardial late gadolinium enhancement, and strain parameters than mean T1 times in HCM patients. LEVEL OF EVIDENCE: 2 Technical Efficacy Stage: 2 J. Magn. Reson. Imaging 2019;49:668-677.

Myocardial fibrosis evaluated by diffusion-weighted imaging and its relationship to 3D contractile function in patients with hypertrophic cardiomyopathy.

BACKGROUND: Previous studies have shown that diffusion-weighted imaging (DWI) is sensitive to myocardial fibrosis in ischemic and nonischemic cardiomyopathy. PURPOSE: To explore the prognostic value of apparent diffusion coefficient (ADC) for detecting myocardial fibrosis and its relationship to the contractile function in hypertrophic cardiomyopathy (HCM). STUDY TYPE: Prospective. POPULATION: A total of 45 HCM patients and 20 controls. FIELD STRENGTH/SEQUENCE: 3.0T cardiac MRI. The cardiac MR sequences included cine, T1 mapping, and DWI. ASSESSMENT: According to the presence of late gadolinium enhancement (LGE) and the extracellular volume (ECV) values (+2 SD of control subjects), respectively, reader W and reader J assessed the value of ADC of each segment for detecting myocardial fibrosis and its relationship to impaired contractile function in HCM patients. STATISTICAL TESTS: Independent sample t-test, Pearson analysis, and intraclass correlation (ICC). RESULTS: The value of ECV was 23.6 ± 3.0% for control. ECV ≥ 29.6% and ECV < 29.6% groups were classified. ADC values in the ECV ≥ 29.6% group were significantly increased compared to the ECV < 29.6% group, (2.41 ± 0.23 µm2 /ms vs. 2.03 ± 0.16 µm2 /ms, P < 0.005). Compared to the LGE - group, ECV (32.1 ± 2.3% vs. 29.0 ± 2.8%, P < 0.005) and ADC (2.60 ± 0.18 µm2 /ms vs. 2.10 ± 0.07 µm2 /ms, P < 0.005) values were significantly increased in the LGE + group. ADC values were linearly associated with ECV values (R2 = 0.65) in HCM patients. ADC values were linearly associated with circumferential and longitudinal strain (R2 = 0.60, R2 = 0.46), as well as circumferential, longitudinal, and radial strain rate (R2 = 0.13, R2 = 0.25, R2 = 0.17, respectively). DATA CONCLUSION: Contractile dysfunction in HCM is predominantly associated with ADC, which is a feasible alternative to ECV and LGE for detecting myocardial fibrosis. LEVEL OF EVIDENCE: 1 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2018;48:1139-1146.

The Paravascular Pathway for Brain Waste Clearance: Current Understanding, Significance and Controversy.

The paravascular pathway, also known as the "glymphatic" pathway, is a recently described system for waste clearance in the brain. According to this model, cerebrospinal fluid (CSF) enters the paravascular spaces surrounding penetrating arteries of the brain, mixes with interstitial fluid (ISF) and solutes in the parenchyma, and exits along paravascular spaces of draining veins. Studies have shown that metabolic waste products and solutes, including proteins involved in the pathogenesis of neurodegenerative diseases such as amyloid-beta, may be cleared by this pathway. Consequently, a growing body of research has begun to explore the association between glymphatic dysfunction and various disease states. However, significant controversy exists in the literature regarding both the direction of waste clearance as well as the anatomical space in which the waste-fluid mixture is contained. Some studies have found no evidence of interstitial solute clearance along the paravascular space of veins. Rather, they demonstrate a perivascular pathway in which waste is cleared from the brain along an anatomically distinct perivascular space in a direction opposite to that of paravascular flow. Although possible explanations have been offered, none have been able to fully reconcile the discrepancies in the literature, and many questions remain. Given the therapeutic potential that a comprehensive understanding of brain waste clearance pathways might offer, further research and clarification is highly warranted.

Aneroid Blood Pressure Manometer Calibration Rates of Devices Used in Home Health.

Hypertension is associated with cardiovascular disease, stroke, and a range of other medical sequelae. Accurate blood pressure (BP) readings, which depend on the integrity and calibration of the measuring device, are essential to identifying suboptimal BP. This study describes calibration rates of aneroid BP devices (a) utilized in home healthcare (HHC) and (b) having the needle resting within the zero accuracy indicator. BP devices from one branch of a home care agency were inspected and checked for calibration according to the protocol set forth by the European Society of Hypertension. Of the 125 devices measured, 78.4% were in calibration. Of the 94 devices with the gauge needle resting in the zero accuracy indicator, 11.7% were not in calibration; whereas, 51.6% of the 31 devices with the gauge needle resting outside the zero accuracy indicator were found not in calibration. Twenty-one devices were not checked for calibration due to inflation bulb malfunction, tubing tears, or excessive wear. Furthermore, visual inspection of the needle placement did not confirm a device as being in or out of calibration. Proper maintenance and routine calibration of BP equipment is foundational to assuring accuracy of BP readings obtained by HHC providers.