基于能谱CT探讨低对比剂用量时肺动脉造影最佳单能量水平
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摘要
目的:探讨低对比剂用量CTPA的能谱最佳单能量水平。方法:前瞻性收集临床拟诊肺动脉栓塞并行能谱扫描模式(GSI)低对比剂用量(25ml)患者30例。扫描条件为:扫描协议为GSI-36:260mA,对比剂用量25ml(350mgI/ml,4. 0ml/s),小剂量(8ml)团注测试法监测。扫描完成后采用自适应统计迭代算法(ASiR:50%)将图像重建为层厚为1. 25mm的60-80keV(间隔5keV) 5组单能量图像。分别测量5组单能量图像的主肺动脉(MPA)、右肺动脉(RPA)、左肺动脉(LPA)、右下肺动脉(RLPA)及左下肺动脉(LLPA)的CT值和SD值以及同层面背部肌肉的CT值,计算SNR及CNR并用于分析比较。由两名有经验的影像科医师采用5级评分法对5组图像进行主观评价。采用SPSS 19. 0统计学软件分析上述数据,以P <0. 05为差异有统计学意义。结果:5组单能量图像中各肺动脉的CT值随能量升高而降低,60keV-70keV单能量图像的肺动脉平均CT均大于300HU。65keV单能量图像的平均SNR及CNR最高,平均SD最低,与60keV和70keV图像两两比较差异均有统计学意义(p均<0. 05)。两名放射科医师对65keV图像评分最高,但与60keV和70keV图像两两比较差异均无统计学意义(p均>0. 05)。结论:能谱扫描模式低对比剂用量肺动脉造影中,65KeV图像平均SNR及CNR最高,平均噪声较最低,以及最高的主观评分,可作为低对比剂用量CTPA中的最佳单能量图像水平。
Purpose: To determine the optimal monochromatic energy levels in dual-energy Spectral CT pulmonary angiography( CTPA) with low contrast dosage. Materials and Methods: Thirty patients with suspected pulmonary embolism( PE) underwent dual-energy Spectral CTPA with low radiation and low contrast doses: scanning protocol of GSI-36 with260 mA,and 25 ml contrast( 350 mgI/ml) with 4. 0 ml/s injection speed. The monochromatic images from 60-80 keV( interval 5 keV) were reconstructed using a 50% adaptive statistical iterative reconstruction( 50% ASiR) algorithm at 1. 25 mm slice thickness. The CT attenuation and standard deviation( SD) values of the main,right,left,right lower and left lower pulmonary arteries and the back muscle at the same level were measured on the 60-80 keV images,and signal-to-noise ratio( SNR) and contrast-to-noise ratio( CNR) were calculated and analyzed. The subjective image quality was evaluated by two experienced radiologists using a 5-level scoring method independently. Measurements were analyzed using SPSS19. 0 statistical software. Results: CT attenuation values of the pulmonary arteries decreased with the increase of energy level in the five-energy groups,with valuesgreater than 300 HU at 60 keV-70 keV energies. The 65 keV image had the highest SNR and CNR and lowest SD,with significant differences compared with those of other image sets( p < 0. 05). The subjective quality scores for the 65 keV image was judged to be the highest by the two radiologists,but was not significantly different from 60 keV and 70 keV( all p > 0. 05). Conclusions: The 65 keV monochromatic images provided the highest SNR,CNR and subjective scores with the lowest image noise in dual-energy Spectral CTPA with low contrast dosage.
Purpose: To determine the optimal monochromatic energy levels in dual-energy Spectral CT pulmonary angiography( CTPA) with low contrast dosage. Materials and Methods: Thirty patients with suspected pulmonary embolism( PE) underwent dual-energy Spectral CTPA with low radiation and low contrast doses: scanning protocol of GSI-36 with260 mA,and 25 ml contrast( 350 mgI/ml) with 4. 0 ml/s injection speed. The monochromatic images from 60-80 keV( interval 5 keV) were reconstructed using a 50% adaptive statistical iterative reconstruction( 50% ASiR) algorithm at 1. 25 mm slice thickness. The CT attenuation and standard deviation( SD) values of the main,right,left,right lower and left lower pulmonary arteries and the back muscle at the same level were measured on the 60-80 keV images,and signal-to-noise ratio( SNR) and contrast-to-noise ratio( CNR) were calculated and analyzed. The subjective image quality was evaluated by two experienced radiologists using a 5-level scoring method independently. Measurements were analyzed using SPSS19. 0 statistical software. Results: CT attenuation values of the pulmonary arteries decreased with the increase of energy level in the five-energy groups,with valuesgreater than 300 HU at 60 keV-70 keV energies. The 65 keV image had the highest SNR and CNR and lowest SD,with significant differences compared with those of other image sets( p < 0. 05). The subjective quality scores for the 65 keV image was judged to be the highest by the two radiologists,but was not significantly different from 60 keV and 70 keV( all p > 0. 05). Conclusions: The 65 keV monochromatic images provided the highest SNR,CNR and subjective scores with the lowest image noise in dual-energy Spectral CTPA with low contrast dosage.
引文
1 Task Force for the Diagnosis and Management of Acute Pulmonary Embolism of the European Society of Cardiology(ESC).2014 ESC guidelines on the diagnosis and management of acute pulmonary embolism.[J].Eur Heart J.2014Nov 14;35(43):3033-3069.
2 Ren Y,Shuman W P,Earls J P,et al.Reduced iodine load at CT pulmonary angiography with dual-energy monochromatic imaging:comparison with standard CT pulmonary angiography--a prospective randomized trial.[J].Radiology,2012,262(1):290-297.
3 Bhalla S,Lopez I.MDCT of acute thrombotic and nonthrombotic pulmonary emboli.[J].European Journal of Radiology,2007,64(1):54-64.
4 Bosson J L,Pernod G,Joubin E,et al.Non-conform diagnostic management ofpulmonary embolism suspected patients is responsible forahigher risk ofthrombotic event occurrence[J].Journal Des Maladies Vasculaires,2007,32(1):15-22.
5 Wichmann J L,Katzberg RW,Litwin SE,et al.ContrastInduced Nephropathy.[J].Circulation.2015 Nov17;132(20):1931-1936.
6 Thomsen H S,Morcos S K.Contrast media and the kidney:European Society of Urogenital Radiology(ESUR)guidelines.[J].British Journal of Radiology,2003,76(908):513-518.
7 Mccullough P A,Adam A,Becker C R,et al.Epidemiology and Prognostic Implications of Contrast-Induced Nephropathy[J].American Journal of Cardiology,2006,98(6A):5-13.
8 Kevin Nash,Abdul Hafeez,Susan Hou.Hospital-acquired renal insufficiency[J].Am J Kidney Dis,2002,39(5):930-936.
9 Lüders F,Meyborg M,Malyar N,et al.The Preinterventional Cystatin-Creatinine-Ratio:A Prognostic Marker for Contrast Medium-Induced Acute Kidney Injury and Long-Term All-Cause Mortality[J].Nephron,2015,59(12):2970-2982.
10张龙江,卢光明.CT血管成像静脉注射碘对比剂的原则和策略[J].中华放射学杂志,2011,45(6):597-600.
11 Giancarlo M,Emilio A,Jeness C,et al.Contrast volume during primary percutaneous coronary intervention and subsequent contrast-induced nephropathy and mortality.[J].Science,2009,150(3):170-177.
12 Nyman U,Bjrk J,Aspelin P,et al.Contrast medium dose-to-GFR ratio:a measure of systemic exposure to predict contrast-induced nephropathy after percutaneous coronary intervention.[J].Acta Radiologica,2008,49(6):658-667.
13林晓珠,福井利佳,沈云,等.腹部增强能谱CT成像在肾功能不全患者低剂量对比剂扫描中的应用价值[J].中华放射学杂志,2014,48(10):816-821.
14 Davenport M S,Khalatbari S,Dillman J R,et al.Contrast material-induced nephrotoxicity and intravenous low-osmolality iodinated contrast material.[J].Radiology,2013,268(3):719-728.
15陈克敏.能谱CT的基本原理与临床应用[M].科学出版社,2012.
16夏巍,吴勇建,尹肖睿,等.宝石能谱CT低对比剂量肺动脉造影的可行性研究[J].实用放射学杂志,2014(6):1021-1025.
17 Huda W,Ogden K M.Converting dose-length product to effective dose at CT[J].International Journal of Medical Radiology,2008,248(3):995-1003.
18 Hunsaker AR,Oliva IB,Cai T,et al.Contrast opacification using a reduced volume of iodinated contrast material and low peak kilovoltage in pulmonary CT angiography:Objective and subjectiveevaluation.AJR Am J Roentgenol.2010 Aug;195(2):W118-24.
19 Wittram C.How I do it:CT pulmonary angiography.[J].Ajr American Journal of Roentgenology,2007,188(5):1255-1261.
20 Mourits M M,Nijhof W H,van Leuken M H,et al.Reducing contrast medium volume and tube voltage in CT angiography of the pulmonary artery.[J].Clinical Radiology,2016,71(6):615.e7-615.e13.
21 Wu C C,Lee E W,Suh R D,et al.Pulmonary 64-MDCTangiography with 30 m L of IV contrast material:vascular enhancement and image quality.[J].American Journal of Roentgenology,2012,199(6):1247-51.
22 Lu G M,Luo S,Meinel F G,et al.High-pitch computed tomography pulmonary angiography with iterative reconstruction at 80 k Vp and 20 m L contrast agent volume[J].European Radiology,2014,24(12):3260-3268.
23林晓珠,沈云,陈克敏.CT能谱成像的基本原理与临床应用研究进展[J].中华放射学杂志,2011,45(8):798-800.
24 K Matsumoto,M Jinzaki,Y Tanami,et al.Virtual monochromatic spectral imaging with fast kilovoltage switching:improved image quality as compared with that obtained with conventional 120-k Vp CT[J].Radiology,2011,259(1):257-262.
25 Cheng J,Yin Y,Wu H,et al.Optimal monochromatic energy levels in spectral CT pulmonary angiography for the evaluation of pulmonary embolism.[J].Plos One,2013,8(5):e63140.
26 Apfaltrer P,Sudarski S,Schneider D,et al.Value of monoenergetic low-k V dual energy CT datasets for improved image quality of CT pulmonary angiography[J].European Journal of Radiology,2014,83(2):322-328.
27 Ohana M,Labani A,Jeung M Y,et al.Iterative reconstruction in single source dual-energy CT pulmonary angiography:Is it sufficient to achieve a radiation dose as low as state-of-the-art single-energy CTPA[J].European Journal of Radiology,2015,84(11):2314-20.
28 Saade C,Bourne R,El-Merhi F,et al.An optimised patient-specific approach to administration of contrast agent for CT pulmonary angiography.[J].European Radiology,2013,23(11):3205-3212.
29 Piechowiak E I,Peter J F,Kleb B,et al.Intravenous Iodinated Contrast Agents Amplify DNA Radiation Damage at CT.[J].Radiology,2015,275(3):692-697.
30 Saade C,Mayat A,El-Merhi F.Exponentially Decelerated Contrast MediaInjection Rate Combined With a Novel Patient-Specific Contrast Formula Reduces Contrast Volume Administration and Radiation Dose During Computed Tomography Pulmonary Angiography.J Comput Assist Tomogr.2016,40(3):370-374.
31 Montet X,Hachulla A L,Neroladaki A,et al.Image quality of low m A CT pulmonary angiography reconstructed with model based iterative reconstruction versus standard CT pulmonary angiography reconstructed with filtered back projection:an equivalency trial[J].European Radiology,2015,25(6):1665-1671.
2 Ren Y,Shuman W P,Earls J P,et al.Reduced iodine load at CT pulmonary angiography with dual-energy monochromatic imaging:comparison with standard CT pulmonary angiography--a prospective randomized trial.[J].Radiology,2012,262(1):290-297.
3 Bhalla S,Lopez I.MDCT of acute thrombotic and nonthrombotic pulmonary emboli.[J].European Journal of Radiology,2007,64(1):54-64.
4 Bosson J L,Pernod G,Joubin E,et al.Non-conform diagnostic management ofpulmonary embolism suspected patients is responsible forahigher risk ofthrombotic event occurrence[J].Journal Des Maladies Vasculaires,2007,32(1):15-22.
5 Wichmann J L,Katzberg RW,Litwin SE,et al.ContrastInduced Nephropathy.[J].Circulation.2015 Nov17;132(20):1931-1936.
6 Thomsen H S,Morcos S K.Contrast media and the kidney:European Society of Urogenital Radiology(ESUR)guidelines.[J].British Journal of Radiology,2003,76(908):513-518.
7 Mccullough P A,Adam A,Becker C R,et al.Epidemiology and Prognostic Implications of Contrast-Induced Nephropathy[J].American Journal of Cardiology,2006,98(6A):5-13.
8 Kevin Nash,Abdul Hafeez,Susan Hou.Hospital-acquired renal insufficiency[J].Am J Kidney Dis,2002,39(5):930-936.
9 Lüders F,Meyborg M,Malyar N,et al.The Preinterventional Cystatin-Creatinine-Ratio:A Prognostic Marker for Contrast Medium-Induced Acute Kidney Injury and Long-Term All-Cause Mortality[J].Nephron,2015,59(12):2970-2982.
10张龙江,卢光明.CT血管成像静脉注射碘对比剂的原则和策略[J].中华放射学杂志,2011,45(6):597-600.
11 Giancarlo M,Emilio A,Jeness C,et al.Contrast volume during primary percutaneous coronary intervention and subsequent contrast-induced nephropathy and mortality.[J].Science,2009,150(3):170-177.
12 Nyman U,Bjrk J,Aspelin P,et al.Contrast medium dose-to-GFR ratio:a measure of systemic exposure to predict contrast-induced nephropathy after percutaneous coronary intervention.[J].Acta Radiologica,2008,49(6):658-667.
13林晓珠,福井利佳,沈云,等.腹部增强能谱CT成像在肾功能不全患者低剂量对比剂扫描中的应用价值[J].中华放射学杂志,2014,48(10):816-821.
14 Davenport M S,Khalatbari S,Dillman J R,et al.Contrast material-induced nephrotoxicity and intravenous low-osmolality iodinated contrast material.[J].Radiology,2013,268(3):719-728.
15陈克敏.能谱CT的基本原理与临床应用[M].科学出版社,2012.
16夏巍,吴勇建,尹肖睿,等.宝石能谱CT低对比剂量肺动脉造影的可行性研究[J].实用放射学杂志,2014(6):1021-1025.
17 Huda W,Ogden K M.Converting dose-length product to effective dose at CT[J].International Journal of Medical Radiology,2008,248(3):995-1003.
18 Hunsaker AR,Oliva IB,Cai T,et al.Contrast opacification using a reduced volume of iodinated contrast material and low peak kilovoltage in pulmonary CT angiography:Objective and subjectiveevaluation.AJR Am J Roentgenol.2010 Aug;195(2):W118-24.
19 Wittram C.How I do it:CT pulmonary angiography.[J].Ajr American Journal of Roentgenology,2007,188(5):1255-1261.
20 Mourits M M,Nijhof W H,van Leuken M H,et al.Reducing contrast medium volume and tube voltage in CT angiography of the pulmonary artery.[J].Clinical Radiology,2016,71(6):615.e7-615.e13.
21 Wu C C,Lee E W,Suh R D,et al.Pulmonary 64-MDCTangiography with 30 m L of IV contrast material:vascular enhancement and image quality.[J].American Journal of Roentgenology,2012,199(6):1247-51.
22 Lu G M,Luo S,Meinel F G,et al.High-pitch computed tomography pulmonary angiography with iterative reconstruction at 80 k Vp and 20 m L contrast agent volume[J].European Radiology,2014,24(12):3260-3268.
23林晓珠,沈云,陈克敏.CT能谱成像的基本原理与临床应用研究进展[J].中华放射学杂志,2011,45(8):798-800.
24 K Matsumoto,M Jinzaki,Y Tanami,et al.Virtual monochromatic spectral imaging with fast kilovoltage switching:improved image quality as compared with that obtained with conventional 120-k Vp CT[J].Radiology,2011,259(1):257-262.
25 Cheng J,Yin Y,Wu H,et al.Optimal monochromatic energy levels in spectral CT pulmonary angiography for the evaluation of pulmonary embolism.[J].Plos One,2013,8(5):e63140.
26 Apfaltrer P,Sudarski S,Schneider D,et al.Value of monoenergetic low-k V dual energy CT datasets for improved image quality of CT pulmonary angiography[J].European Journal of Radiology,2014,83(2):322-328.
27 Ohana M,Labani A,Jeung M Y,et al.Iterative reconstruction in single source dual-energy CT pulmonary angiography:Is it sufficient to achieve a radiation dose as low as state-of-the-art single-energy CTPA[J].European Journal of Radiology,2015,84(11):2314-20.
28 Saade C,Bourne R,El-Merhi F,et al.An optimised patient-specific approach to administration of contrast agent for CT pulmonary angiography.[J].European Radiology,2013,23(11):3205-3212.
29 Piechowiak E I,Peter J F,Kleb B,et al.Intravenous Iodinated Contrast Agents Amplify DNA Radiation Damage at CT.[J].Radiology,2015,275(3):692-697.
30 Saade C,Mayat A,El-Merhi F.Exponentially Decelerated Contrast MediaInjection Rate Combined With a Novel Patient-Specific Contrast Formula Reduces Contrast Volume Administration and Radiation Dose During Computed Tomography Pulmonary Angiography.J Comput Assist Tomogr.2016,40(3):370-374.
31 Montet X,Hachulla A L,Neroladaki A,et al.Image quality of low m A CT pulmonary angiography reconstructed with model based iterative reconstruction versus standard CT pulmonary angiography reconstructed with filtered back projection:an equivalency trial[J].European Radiology,2015,25(6):1665-1671.