Image quality, radiation dose and diagnostic accuracy of 70 kVp whole brain volumetric CT perfusion imaging: a preliminary study.

Purpose: To evaluate image quality and diagnostic accuracy for acute infarct detection and radiation dose of 70 kVp whole brain CT perfusion (CTP) and CT angiography (CTA) reconstructed from CTP source data.

Methods: Patients were divided into three groups (n = 50 each): group A, 80 kVp, 21 scanning time points; groups B, 70 kVp, 21 scanning time points; group C, 70 kVp, 17 scanning time points. Objective and subjective image quality of CTP and CTA were compared. Diagnostic accuracy for detecting acute infarct and cerebral artery stenosis ≥ 50 % was calculated for CTP and CTA with diffusion weighted imaging and digital subtraction angiography as reference standards. Effective radiation dose was compared.

Results: There were no differences in any perfusion parameter value between three groups (P > 0.05). No difference was found in subjective image quality between three groups (P > 0.05). Diagnostic accuracy for detecting acute infarct and vascular stenosis showed no difference between three groups (P > 0.05). Compared with group A, radiation doses of groups B and C were decreased by 28 % and 37 % (both P < 0.001), respectively.

Conclusion: Compared with 80 kVp protocol, 70 kVp brain CTP allows comparable vascular and perfusion assessment and lower radiation dose while maintaining high diagnostic accuracy in detecting acute infarct.

Key Points: • 70 kVp whole brain CTP can provide diagnostic image quality. • 70 kVp CTP diagnostic accuracy was maintained vs. 80 kVp protocol. • 70 kVp CTP radiation doses were lower than 80 kVp protocol.