ABSTRACT
Objective:To evaluate the feasibility of low-voltage, low-concentration, and low-volume iodine contrast agent for coronary artery CT imaging in patients with chronic kidney disease (CKD).Methods:A total of 36 patients from July 2016 to January 2018 with CKD who were suspected of having coronary artery disease (CAD) were selected prospectively and were performed with coronary artery CT angiography (CCTA) by randomly divided into control group and observation group. In the control group, 13 patients were scanned with a conventional tube voltage of 120 kV, a step-and-shot (SAS) scanning protocol, 63-85 ml injection of a high-concentration iodine contrast agent (iopromide, 370 mg I/ml), and traditional filtered back projection (FBP) reconstruction algorithm. In the observation group, 23 patients were scanned with a low-voltage SAS scanning scheme based on body mass index (BMI) (100 kV for BMI ≥ 25 kg/m 2 or 80 kV for BMI<25 kg/m 2), isotonic low-concentration iodine agent(iodixanol, 270 mgI/ml), low volume injection (45 ml) and iterative algorithm reconstruction algorithm. The scans for both groups of patients were turned on automatic tube current modulation (4D CareDose). The coronary artery image quality of the two groups was evaluated with subjective and objective method. The radiation dose was calculated based on the product of the dose length product (DLP) and the chest coefficient k. The total iodine intake of the two groups was calculated by the product of the iodine concentration and the injection volume. Changes in renal function were calculated as a percentage decrease in serum creatinine clearance before and on day 3 after examination. Results:Totally 32 patients were performed CCTA successfully. Subjective scores of coronary artery image quality in the control and observation groups were 3.789±0.598 and 3.708±0.717, respectively, with no significant statistically difference( P>0.05). The signal noise ratios were 12.88±4.53 and 13.67±2.08(LAD), 11.9±5.0 and 12.6±5.1(RCA), 12.78±3.15 and 13.22±3.10(LCX), with no significant statistically difference ( P>0.05). The average contrast noise ratios were 10.94±1.31 and 11.27±1.81 (LAD), 10.38±1.90 and 11.01±2.26 (RCA), 11.71±3.15 and 12.49±3.62 (LCX), with no significant statistically difference ( P> 0.05). The average radiation doses in observation and control group were (1.09±0.19) and (2.85±0.59) mSv, respectively, with statistically significant difference between the two groups ( t=20.260, P<0.05). The average iodine intakes of the control and observation group were (2.71±0.37) and (1.22±0.00) g, respectively, with statistically significant difference ( t=18.162, P<0.05). The decreases of serum creatinine clearance within 72 hours after injection of iodine contrast agent in the control group and observation group were (28.75±5.24)% and (11.89±4.98)%, respectively, with significant statistically difference ( χ2=9.004, P<0.05). Conclusions:Triple-low scanning scheme can reduce the total iodine consumption and radiation dose of patients with little effect on renal function and meeting the diagnostic requirements of image quality. It is suitable for CCTA of patients with CKD.
ABSTRACT
Objective To analyze the CT and MRI features of splenic inflammatory myofibroblastoma (SIMF).Methods The CT and MRI images of 6 patients with SIMF were retrospectively analyzed.Results 5 cases underwent CT examination;2 cases did MRI.Six cases of SIMF were all single lesions;the average diameter was (3.9 ± 0.9) cm;the lesions were round or gourdshaped;most have clear boundaries with uneven scan density.On the MRI,the parenchymal part was slightly low signal on T1WI,inhomogeneous hypointensity on T2WI,or high signal on T2WI.After CT or MRI enhancement,lesions were progressively enhanced.Correct preoperative diagnosis was established in only 1 patient.Conclusion In this study,all SIMF cases present as single lesion.The circular appearance and clear boundaries are in common.Asymptotic intensification with map-unenhanced regions is the main enhancement feature.