低剂量CT胰腺灌注扫描中Stellar探测器的应用

Low dose CT pancreatic perfusion with Stellar detector:Comparison with conventional detector

目的比较应用新型光子探测器与常规探测器行低剂量CT胰腺灌注扫描的图像质量及灌注参数差异。方法对36例患者行胰腺灌注扫描,其中对18例采用装配新型光子探测器的第二代双源双能CT扫描(A组),另18例采用装配常规探测器(探测器B)的第二代双源双能CT扫描(B组),比较两组低剂量(80kVp,150mA)胰腺灌注扫描的总辐射剂量、正常胰腺实质的血流量(BF)、血容量(BV)以及腹部各主要脏器的CT值、噪声、SNR差异。结果两组患者在性别、年龄、腹围方面差异均无统计学意义(P均>0.05),总扫描剂量无明显差异(P>0.05),腹部各主要脏器CT值差异无统计学意义(P均>0.05);A组图像噪声低于B组(P<0.01),部分脏器SNR优于B组(P<0.01),两组正常胰腺实质BF、BV均值差异无统计学意义(P>0.05),A组BF和BV标准差均低于B组(P均<0.01)。结论 Stellar探测器在低剂量胰腺灌注CT扫描中能降低图像噪声,提高图像质量,并使灌注参数测定结果更为可靠。

Objective To compare image quality and perfusion parameters in low dose pancreatic CT perfusion imaging （CTPI） obtained with Stellar detector and standard detector. Methods Thirty-six patients who received pancreatic CTPI were retrospectively analyzed. Eighteen of them were scanned with 64-slice dual source CT equipped with Stellar detector （group A）, and the rest were scanned with 64-slice dual source CT equipped with standard detector （group B）. Total radi- ation dose of low dose scan （80 kVp, 150 mA）~, perfusion parameters of normal pancreatic parenchyma including blood flow （BF） and blood volume （BV）, CT value, noise in each main abdominal organ and signal to noise ratio （SNR） were com- pared between groups. Results Patients＂ age, sex distribution, abdminal circumference and total radiation dose showed no significant difference between two groups （P^0.05）. There was no significant difference between two groups in the mean CT value of all abdominal organs （P^0.05）, whereas group A exhibited a lower overall image noise and a better SNR （both P^0.01）. No significant difference was observed in pancreatic parenchymal BV and BF between two groups, where- as the standard deviation of BV and BF were significantly lower in group A （both P^0.01）. Conclusion Stellar detector can improve image quality by decreasing noise in low dose pancreatic CTPI without increasing radiation exposure and obtain reliable values of perfusion parameters.