(99m)Tc-DPD scintigraphy is a highly sensitive technique for imaging cardiac ATTR amyloidosis and is an important investigation in the diagnostic pathway of patients with cardiac amyloidosis. It is not specific for ATTR in isolation but must be interpreted in a broad clinical context to avoid dangerous diagnostic errors. Diffuse skeletal muscle uptake identifies muscle as a hitherto unrecognized site that merits investigation as a target organ in ATTR amyloidosis.

High-grade (Perugini grade 2 or 3) cardiac uptake on bone scintigraphy with 99m Technetium labelled 3,3-diphosphono-1,2-propanodicarboxylic acid (99m Tc-DPD) has lately been confirmed to have high diagnostic sensitivity and specificity for cardiac transthyretin (ATTR) amyloidosis. We sought to determine whether patient stratification by Perugini grade on 99m Tc-DPD scintigraphy has prognostic significance in ATTR amyloidosis. Methods and Results Patient survival from time of 99m Tc-DPD scintigraphy was determined in 602 patients with ATTR amyloidosis, including 377 with wild-type ATTR and 225 with mutant ATTR amyloidosis (ATTRm). Patients were stratified according to Perugini grade (0-3) on 99m Tc-DPD scan. The prognostic significance of additional patient and disease-related factors at baseline were determined. In the whole cohort, the finding of a Perugini grade 0 99m Tc-DPD scan (n=28) was invariably associated with absence of cardiac amyloid according to consensus criteria as well as significantly better patient survival compared to a Perugini grade 1 (n=28), 2 (n=436) or 3 (n=110) 99m Tc-DPD scan (p<0.005). There were no differences in survival between patients with a grade 1, grade 2 or grade 3 99m Tc-DPD scan in wild-type ATTR (n=369), V122I-associated ATTRm (n=92) or T60A-associated ATTRm (n=59) amyloidosis. Cardiac amyloid burden, determined by equilibrium contrast cardiac magnetic resonance imaging, was similar between patients with Perugini grade 2 and Perugini grade 3 99m Tc-DPD scans but skeletal muscle/soft tissue to femur ratio was substantially higher in the latter group (p<0.001). Conclusion 3 99m Tc-DPD scintigraphy is exquisitely sensitive for identification of cardiac ATTR amyloid, but stratification by Perugini grade of positivity at diagnosis has no prognostic significance.

Norovirus infection is a major cause of nonbacterial gastroenteritis. In immunocompetent individuals the illness caused by norovirus is mostly self limiting. Excretion of norovirus has been reported to be prolonged in the immunocompromised including adult HSCT recipients. We report a case series of 13 children who received HSCT and required prolonged parenteral and enteral nutrition due to severe gut dysfunction accompanying protracted norovirus excretion that was monitored by RT-PCR. The median duration of viral excretion was 150 days (range 60-380) and the eventual clearance of norovirus from feces was closely associated with donor T cell recovery in the peripheral blood. There was no disease manifestation beyond the gut but the severity and length of norovirus associated illness suggests that HSCT should be delayed where possible in patients excreting the virus prior to conditioning therapy.

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