Dual energy CT in patients with polycystic kidney disease

Abstract

To evaluate the diagnostic efficacy of dual source-dual energy CT (DECT) in the detection of neoplasia in patients with polycystic kidney disease (PKD). A total of 21 patients with PKD underwent DECT on a dual source system, using kVp settings of Sn140/100 or 140/80. Colour-coded iodine maps and virtual unenhanced images were used to determine enhancement within cysts and to differentiate haemorrhagic from simple cysts. A cut-off of 15HU was used as a threshold for malignancy. In patients with malignancy, histopathology was the gold standard; otherwise, patients underwent follow-up imaging for 150-908days. On the basis of measured enhancement, 13 enhancing masses were seen in 4 patients (12 renal cell cancers and 1 adenoma); follow-up imaging showed no malignancy in 18 patients. Cysts did not enhance by more than 15HU, whereas masses showed a mean enhancement of 45 (25-123)HU. Average radiation exposure was 9.6mSv for the biphasic protocol and 5.8mSv for DECT only. DECT greatly facilitates the detection of malignancy in patients with polycystic kidney disease, at the same time reducing radiation exposure by omission of a true unenhanced phase. • Identification of tumours within polycystic kidneys can be difficult. • Dual energy computed tomography (DECT) provides two separate sets of images. • Iodine maps and virtual non-enhanced (VNE) images can then be calculated. • DECT facilitates screening for potential renal tumours in polycystic kidneys.