The Application Study Of 64-Slice Spiral Computed Tomography In Renal Artery Angiography

Part 1 Influence of injection rates, concentration of contrast media and threshold of Bolus-tracking on image quality of CT angiography of renal arteriesObjective:To evaluate the influence of different injection rates, concentration of contrast media and threshold levels of bolus-tracking technique on renal artery computed tomographic angiography.Methods:In this prospective study, 420 patients were divided randomly intoⅠ～Ⅳgroups as follow: groupⅠ,iohexol (300mgI/mL) and 3mL/s; groupⅡ,iohexol (300mgI/mL) and 4mL/s; groupⅢ,iopromide (370mgI/mL) and 3mL/s; groupⅣ,iopromide (370mgI/mL) and 4mL/s.And each group were divided randomly into A～G 7 subgroups according to different threshold levels: 140.0～149.9HU (A), 150.0～159.9HU (B), 160.0～169.9 HU(C), 170.0～179.9HU (D), 180.0～189.9HU (E), 190.0～ 199.9HU (F), 200.0～209.9HU (G). All data were sent to work station, and three dimensional reconstruction of CTA was performed. All images were graded and recorded by two radiogists on maximum intensity projection (MIP) angiograms. The statistical software of SAS 9.1.3 was used for analysis.Results:1) There was no significant difference of image quality inⅠ～Ⅳgroups.2) Best image quality and vessel depiction of renal CTA were performed with a threshold of 170.0～189.9HU(groupⅠ);170.0～179.9HU(groupⅡ) ; 160.0～189.9HU(groupⅢ) ; 160.0～179.9 HU(groupⅣ).3) Best image quality of renal arteries and branches was performed with iopromide (370mgI/mL) , 4mL/s and threshold of 160.0～179.9 HU.Conclusion:1) Injection rates, concentration of contrast media and threshold levels are influential factors of image quality in renal artery CTA scanning.2) Renal CTA scanning of excellent images was best performed with iopromide (370mgI/mL) ,4mL/s and threshold 160.0～179.9HU. Part 2 Evaluation of Accessory Renal Arteries on 64-Slice Spiral Computed TomographyObjective:To observe the anatomy of with 64-slice spiral CT and provide the information about renal blood supply for treatment of surgery and intervention.Methods:135 cases of plain and enhanced CT scanning of epigastrium or abdomen in our hospital from January, 2007 to January, 2008 were collected to carry out renal artery CT angiography. The occurrence, number, diameter, length and position into the kidney of accessory renal arteries, distance from beginning of renal arteries, and assessment of early branching were graded and recorded by two radiologists. The statistical software of SAS 9.1.3 was used for analysis.Results:70 accessory renal arteries(26.1%) were detected in 56 patients (41.5%).Incidence of one, two and three accessory renal arteries were respectively 76.7%(43/56), 21.4%(12/56), and 1.9%(1/56). There was significant difference between 67.1%(47/70) on the left and 32.9%(23/70) on the right. The occurrence of accessory renal arteries originated form abdominal aorta was 71.5%(50/70), that of the early branching was 28.5%(20/70). 45.7%(32/70) entered the upper kidney pole, 35.7%(25/70) entered the lower kidney pole.Conclusion:SmartPrep technique of 64-slice spiral CT with high concentration of contrast media, fast injection rate and reasonable threshold level can better display accessory renal arteries and provide the valuable information about renal blood supply for treatment of surgery and intervention.