Endogenous assessment of chronic myocardial infarction with T1ρ-mapping in patients

Background

Detection of cardiac fibrosis based on endogenous magnetic resonance (MR) characteristics of the myocardium would yield a measurement that can provide quantitative information, is independent of contrast agent concentration, renal function and timing. In ex vivo myocardial infarction (MI) tissue, it has been shown that a significantly higher T_1ρ is found in the MI region, and studies in animal models of chronic MI showed the first in vivo evidence for the ability to detect myocardial fibrosis with native T_1ρ-mapping. In this study we aimed to translate and validate T_1ρ-mapping for endogenous detection of chronic MI in patients.

Methods

We first performed a study in a porcine animal model of chronic MI to validate the implementation of T_1ρ-mapping on a clinical cardiovascular MR scanner and studied the correlation with histology. Subsequently a clinical protocol was developed, to assess the feasibility of scar tissue detection with native T_1ρ-mapping in patients (n = 21) with chronic MI, and correlated with gold standard late gadolinium enhancement (LGE) CMR. Four T_1ρ-weighted images were acquired using a spin-lock preparation pulse with varying duration (0, 13, 27, 45 ms) and an amplitude of 750 Hz, and a T_1ρ-map was calculated. The resulting T_1ρ-maps and LGE images were scored qualitatively for the presence and extent of myocardial scarring using the 17-segment AHA model.

Results

In the animal model (n = 9) a significantly higher T_1ρ relaxation time was found in the infarct region (61 ± 11 ms), compared to healthy remote myocardium (36 ± 4 ms) . In patients a higher T_1ρ relaxation time (79 ± 11 ms) was found in the infarct region than in remote myocardium (54 ± 6 ms). Overlap in the scoring of scar tissue on LGE images and T_1ρ-maps was 74%.

Conclusion

We have shown the feasibility of native T_1ρ-mapping for detection of infarct area in patients with a chronic myocardial infarction. In the near future, improvements on the T_1ρ -mapping sequence could provide a higher sensitivity and specificity. This endogenous method could be an alternative for LGE imaging, and provide additional quantitative information on myocardial tissue characteristics.     

Why optometry must work from urban and regional Aboriginal Health Services

The gap in vision and ocular health between Aboriginal and Torres Strait Islander Australians and other Australians continues to be significant, yet three‐quarters of the identified Aboriginal and Torres Strait Islander population live in urban and regional areas of Australia where existing eye‐care services are available. In urban Australia, an improvement in the access and use of eye‐health services is required to provide equitable eye‐care outcomes for Australia's Indigenous peoples. Optometric services need to be available within Aboriginal Health Services in urban areas to effectively close the gap for vision.     

Occupational Exposure to Mercury Vapors and Biological Action

In workers exposed to an average atmospheric mercury vapor concentration below the current threshold limit value (TLV, 0.050 mg/cu m), the following biological changes were detected: increased blood and urine mercury concentrations, increased plasma galactosidase and plasma catalase activities, decreased red blood cell (RBC) cholinesterase activity. A significant correlation was found between airborne mercury level and urinary mercury concentration (r = 0.47), between mercury concentration in blood and in urine (r = 0.36), and between airborne mercury concentration and RBC cholinesterase inhibition (r = 0.33). Serum cholinesterase, RBC δ-aminolevulinic acid (ALA) dehydratase, and urine ALA levels were normal. No significant anomalies were found on the amino acid chromatographs and protein electrophoresis of serum and urine.     

A codesigned integrated kidney and diabetes model of care improves patient activation among patients from culturally and linguistically diverse backgrounds

Background

Little is known about the relationship between patients' cultural and linguistic backgrounds and patient activation, especially in people with diabetes and chronic kidney disease (CKD). We examined the association between culturally and linguistically diverse (CALD) background and patient activation and evaluated the impact of a codesigned integrated kidney and diabetes model of care on patient activation by CALD status in people with diabetes and CKD.

Methods

This longitudinal study recruited adults with diabetes and CKD (Stage 3a or worse) who attended a new diabetes and kidney disease service at a tertiary hospital. All completed the patient activation measure at baseline and after 12 months and had demographic and clinical data collected. Patients from CALD backgrounds included individuals who spoke a language other than English at home, while those from non-CALD backgrounds spoke English only as their primary language. Paired t-tests compared baseline and 12-month patient activation scores by CALD status.

Results

Patients from CALD backgrounds had lower activation scores (52.1 ± 17.6) compared to those from non-CALD backgrounds (58.5 ± 14.6) at baseline. Within-group comparisons showed that patient activation scores for patients from CALD backgrounds significantly improved by 7 points from baseline to 12 months follow-up (52.1 ± 17.6–59.4 ± 14.7), and no significant change was observed for those from non-CALD backgrounds (58.5 ± 14.6–58.8 ± 13.6).

Conclusions

Among patients with diabetes and CKD, those from CALD backgrounds report worse activation scores. Interventions that support people from CALD backgrounds with comorbid diabetes and CKD, such as the integrated kidney and diabetes model of care, may address racial and ethnic disparities that exist in patient activation and thus improve clinical outcomes.

Patient or Public Contribution

Patients, caregivers and national consumer advocacy organisations (Diabetes Australia and Kidney Health Australia) codesigned a new model of care in partnership with healthcare professionals and researchers. The development of the model of care was informed by focus groups of patients and healthcare professionals and semi-structured interviews of caregivers and healthcare professionals. Patients and caregivers also provided a rigorous evaluation of the new model of care, highlighting its strengths and weaknesses.