Measurement of liver and spleen interstitial volume in patients with systemic amyloid light-chain amyloidosis using equilibrium contrast CT.

OBJECTIVES

To investigate equilibrium contrast-enhanced CT (EQ-CT) measurement of extracellular volume fraction (ECV) in patients with systemic amyloid light-chain (AL) amyloidosis, testing the hypothesis that ECV becomes elevated in the liver and spleen and ECV correlates with other estimates of organ amyloid burden.

METHODS

26 patients with AL amyloidosis underwent EQ-CT, and ECV was measured in the liver and spleen. Patients also underwent serum amyloid P (SAP) component scintigraphy with grading of liver and spleen involvement. Mann-Whitney U test was used to test for a difference between patients with amyloid deposition (SAP grade 1-3) and those without (SAP grade 0). Variation in ECV across SAP grades was assessed using the Kruskal-Wallis test and association between ECV and SAP grades with Spearman correlation.

RESULTS

Mean ECV in the spleen and liver was significantly greater (p < 0.0005) in amyloidotic organs (SAP grade 1-3) [spleen, liver: 0.430, 0.375] compared with healthy tissues [spleen, liver: 0.304, 0.269]. ECV increased with increasing amyloid burden, showing positive correlation with SAP grade in both the liver (r = 0.758) and spleen (r = 0.867).

CONCLUSION

In patients with systemic AL amyloidosis, EQ-CT can demonstrate increased spleen and liver ECV, which is associated with amyloid disease burden.