Estimation of prevalence of transthyretin (ATTR) cardiac amyloidosis in an Australian subpopulation using bone scans with echocardiography and clinical correlation.

BACKGROUND: Bone scans differentiate transthyretin (ATTR) cardiac amyloidosis from light chain amyloidosis and other causes of increased left ventricular (LV) wall thickness. We examined the prevalence and implications of cardiac uptake in the general population. METHODS: Patients were included based on having undertaken a bone scan for non-cardiac indications using Technetium 99m hydroxymethylene diphosphonate (HMDP) or Technetium 99m methylene diphosphonate (MDP). Blinded image review was undertaken. Positive was defined as cardiac uptake ≥ rib AND heart/whole body ratio (H/WB) > 0.0388. Echocardiography and clinical records were reviewed. RESULTS: 6918 patients were included. 15/3472 HMDP scans were positive (14 males, 1 female): none in individuals aged < 65; 1.44% in males and 0.17% in females ≥ 65; 6.15% in males and 1.69% in females ≥ 85. Only 1/3446 MDP scans were positive. All HMDP positive patients had increased septal wall thickness on echocardiography. H/WB correlated positively with LV mass, and negatively with LV ejection fraction. No individual had an explanation other than ATTR for their positive scan. CONCLUSION: In this Australian subpopulation, the prevalence of positive bone scans consistent with cardiac ATTR is 0% in individuals aged < 65. Prevalence increased with age, reaching 6.15% in men ≥ 85. The amount of HMDP uptake correlated with echocardiographic features of more advanced cardiac involvement. MDP does not appear useful in ATTR.

The current status of quantitative SPECT/CT in the assessment of transthyretin cardiac amyloidosis.

Nuclear medicine bone scans differentiate ATTR cardiomyopathy (ATTR-CM) from light chain cardiac amyloidosis and other myocardial disorders, helping to make the diagnosis without biopsy. Standard bone scans are not absolutely quantitative, so are assessed by comparing the heart to other tissues. The standard visual scoring system compares heart to bone. This accurately diagnoses ATTR-CM and has been validated in a multicenter study, but has limitations. Semiquantitative techniques including heart/contralateral thorax (H/CL) and heart/whole body ratio (H/WB) improve on visual scoring but still rely on extracardiac sites as comparators. Absolute quantitation of myocardial uptake using quantitative SPECT should help overcome these shortcomings. In ATTR-CM, this technique is practical, accurately makes the diagnosis and provides information that is not identical to visual scores. However, more work needs to be done. The reproducibility in ATTR-CM must be tested. Larger studies need to be undertaken to determine whether quantitative SPECT measurements can assess prognosis, disease progression or treatment response. As ATTR-CM is relatively uncommon multicenter trials will help recruit enough subjects to answer these questions. Accurate measurement techniques are needed in ATTR-CM to enable appropriate use of proven therapy and to conduct trials of new therapeutic agents. Quantitative bone scans offer a promising avenue.

Easing anxiety in preparation for pediatric magnetic resonance imaging: a pilot study using animal-assisted therapy.

BACKGROUND: Children undergoing magnetic resonance imaging (MRI) can experience negative emotions both before and during their scan, causing them to move and often necessitating the use of procedural sedation. Several strategies to improve patient compliance have been attempted. OBJECTIVE: This study was designed to evaluate the effectiveness of a non-pharmacological intervention to reduce anxiety in pediatric patients preparing for MRI using animal-assisted therapy. MATERIALS AND METHODS: An animal intervention pilot study was performed in patients who agreed in advance to interact with a dog. Patients and caregivers filled out questionnaires, including questions designed to capture changes in patient emotion before and after the intervention. MRI diagnostic quality was compared to age- and gender-matched control groups with and without general anesthesia. RESULTS: The intervention in 21 patients comparing pre- and post-scan surveys demonstrated a statistically significant improvement in patient anxiety levels (P<0.01). Diagnostic MRI scans were achieved in 19/21 (90%), with no significant difference in exam quality or times compared against control groups. The majority of caregivers and staff members agreed strongly that patients benefited from the therapy dog's presence. CONCLUSION: The use of animal-assisted therapy in a pilot group in our MRI division resulted in a beneficial effect on patients' emotional status, easing anxiety in preparation for scheduled scans, without impacting MRI quality or duration. Further randomized studies will be needed to demonstrate its significance in reducing sedation rates in children undergoing MRI.