RESUMEN
OBJECTIVE: To investigate the feasibility and image quality of high-pitch CT pulmonary angiography (CTPA) with reduced iodine volume in normal weight patients. METHODS: In total, 81 normal weight patients undergoing CTPA for suspected pulmonary arterial embolism were retrospectively included: 41 in high-pitch mode with 20 mL of contrast medium (CM); and 40 with normal pitch and 50 mL of CM. Subjective image quality was assessed and rated on a 3-point scale. For objective image quality, attenuation and noise values were measured in all pulmonary arteries from the trunk to segmental level. Contrast-to-noise ratio (CNR) was calculated. Radiation dose estimations were recorded. RESULTS: There were no statistically significant differences in patient and scan demographics between high-pitch and standard CTPA. Subjective image quality was rated good to excellent in over 90% of all exams with no significant group differences (p = 0.32). Median contrast opacification was lower in high-pitch CTPA (283.18 [216.06-368.67] HU, 386.81 [320.57-526.12] HU; p = 0.0001). CNR reached a minimum of eight in all segmented arteries, but was lower in high-pitch CTPA (8.79 [5.82-12.42], 11.01 [9.19-17.90]; p = 0.005). Median effective dose of high-pitch CTPA was lower (1.04 [0.72-1.27] mSv/mGy·cm; 1.49 [1.07-2.05] mSv/mGy·cm; p < 0.0001). CONCLUSION: High-pitch CTPA using ultra-low contrast volume (20 mL) rendered diagnostic images for the detection of pulmonary arterial embolism in most instances. Compared to standard CTPA, the high-pitch CTPA exams with drastically reduced contrast medium volume had also concomitantly reduced radiation exposure. However, objective image quality of high-pitch CTPA was worse, though likely still within acceptable limits for confident diagnosis. CLINICAL RELEVANCE: This study provides valuable insights on the performance of a high-pitch dual-source CTPA protocol, offering potential benefits in reducing contrast medium and radiation dose while maintaining sufficient image quality for accurate diagnosis in patients suspected of pulmonary embolism. KEY POINTS: ⢠High-pitch CT pulmonary angiography (CTPA) with ultra-low volume of contrast medium and reduced radiation dose renders diagnostic examinations with comparable subjective image quality to standard CTPA in most patients. ⢠Objective image quality of high-pitch CTPA is reduced compared to standard CTPA, but contrast opacification and contrast-to-noise ratio remain above diagnostic thresholds. ⢠Challenges of high-pitch CTPA may potentially be encountered in patients with severe heart failure or when performing a Valsalva maneuver during the examination.
Asunto(s)
Hipertensión Pulmonar , Embolia Pulmonar , Humanos , Estudios Retrospectivos , Embolia Pulmonar/diagnóstico por imagen , Arteria Pulmonar/diagnóstico por imagen , Tomografía Computarizada por Rayos X/métodos , Angiografía/métodos , Dosis de Radiación , Angiografía por Tomografía Computarizada/métodos , Medios de ContrasteRESUMEN
OBJECTIVE: To examine differences in image quality of the coronary arteries when performing high-pitch non-electrocardiography (ECG)-gated scans on the second-generation (2G) and third-generation (3G) dual-source CT scanners. METHODS: We retrospectively examined patients with high-pitch non-ECG-gated CT angiography (CTA) of the chest or chest/abdomen/pelvis. Outpatient scans from 59 patients in the 3G high-pitch group and 53 patients in the 2G high-pitch group were included. Two blinded cardiac imagers independently scored the coronary image quality using a 4-point Likert scale (from completely diagnostic to completely non-diagnostic) and evaluated the presence of coronary artery disease. RESULTS: Diagnostic image quality of the coronaries in high-pitch CTA exams using 3G scanner was improved compared to 2G scanner, both on a per-vessel basis (45-94% versus 23-86%) and on a per-study basis (34% versus 14%). The 3G group showed a statistically significant improvement in image quality when evaluating the left main coronary, right coronary, and overall coronary arteries. Coronary artery disease was detected in 65% of high-pitch scans. Radiation doses in terms of CTDIvol and DLP were lower for 3G high-pitch scans (7.5â¯mGy and 491â¯mGy∗cm) compared to 2G high-pitch scans (14.8â¯mGy and 911â¯mGy∗cm). CONCLUSIONS: We found a higher proportion of diagnostic image quality of the coronary arteries in high-pitch non-ECG-gated CTA exams using a 3G dual-source CT scanner, compared to 2G. In scans with diagnostic image quality, underlying coronary artery disease may be confidently diagnosed and should prompt considerations for further management in the appropriate clinical setting.
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Angiografía por Tomografía Computarizada/métodos , Enfermedad de la Arteria Coronaria/diagnóstico por imagen , Angiografía Coronaria/métodos , Femenino , Frecuencia Cardíaca/fisiología , Humanos , Masculino , Persona de Mediana Edad , Dosis de Radiación , Estudios RetrospectivosRESUMEN
Coronary CT angiography (CCTA) suffers from a reduced diagnostic accuracy in patients with heavily calcified coronary arteries or prior myocardial revascularisation due to artefacts caused by calcifications and stent material. CT myocardial perfusion imaging (CTMPI) yields high potential for the detection of myocardial ischemia and might help to overcome the above mentioned limitations. We analysed CT single-phase perfusion using high-pitch helical image acquisition technique in patients with prior myocardial revascularisation. Thirty-six patients with an indication for invasive coronary angiography (28 with coronary stents, 2 with coronary artery bypass grafts and 6 with both) were included in this prospective study at two study sites. All patients were examined on a 2nd generation dual-source CT system. Stress CT images were obtained using a prospectively ECG-triggered single-phase high-pitch helical image acquisition technique. During stress the tracer for myocardial perfusion (MP) SPECT imaging was administered. Rest CT images were acquired using prospectively ECG-triggered sequential CT. MP-SPECT imaging and invasive coronary angiography served as standard of reference. In this heavily diseased patient cohort CCTA alone showed a low overall diagnostic accuracy for detection of hemodynamically relevant coronary artery stenosis of only 31% on a per-patient base and 60% on a per-vessel base. Combining CCTA and CTMPI allowed for a significantly higher overall diagnostic accuracy of 78% on a per-patient base and 92% on a per-vessel base (p < 0.001). Mean radiation dose for stress CT scans was 0.9 mSv, mean radiation dose for rest CT scans was 5.0 mSv. In symptomatic patients with known coronary artery disease and prior myocardial revascularization combining CCTA and CTMPI showed significantly higher diagnostic accuracy in detection of hemodynamically significant coronary artery stenosis when compared to CCTA alone.
Asunto(s)
Técnicas de Imagen Sincronizada Cardíacas , Angiografía por Tomografía Computarizada , Angiografía Coronaria/métodos , Circulación Coronaria , Isquemia Miocárdica/diagnóstico por imagen , Imagen de Perfusión Miocárdica/métodos , Tomografía Computarizada de Emisión de Fotón Único , Tomografía Computarizada Espiral , Anciano , Anciano de 80 o más Años , Puente de Arteria Coronaria , Electrocardiografía , Femenino , Alemania , Hemodinámica , Humanos , Masculino , Persona de Mediana Edad , Isquemia Miocárdica/complicaciones , Isquemia Miocárdica/fisiopatología , Isquemia Miocárdica/terapia , Intervención Coronaria Percutánea/instrumentación , Valor Predictivo de las Pruebas , Estudios Prospectivos , Interpretación de Imagen Radiográfica Asistida por Computador , Reproducibilidad de los Resultados , StentsRESUMEN
BACKGROUND: Coronary CT angiography (CCTA) is usually performed during breath holding to reduce motion artifacts caused by respiration. However, some patients are not able to follow the breathing commands adequately due to deafness, hearing impairment, agitation or pulmonary diseases. The aim of this study was to evaluate the potential of high-pitch CCTA in free breathing patients when compared to breath holding patients. METHODS: In this study we evaluated 40 patients (20 free breathing and 20 breath holding patients) with a heart rate of 60 bpm or below referred for CCTA who were examined on a 2nd generation dual-source CT system. Image quality of each coronary artery segment was rated using a 4-point grading scale (1: non diagnostic-4: excellent). RESULTS: Mean heart rate during image acquisition was 52 ± 5 bpm in both groups. There was no significant difference in mean image quality, slightly favoring image acquisition during breath holding (mean image quality score 3.76 ± 0.32 in breath holding patients vs. 3.61 ± 0.45 in free breathing patients; p = 0.411). Due to a smaller amount of injected contrast medium, there was a trend for signal intensity to be slightly lower in free breathing patients, but this was not statistically significant (435 ± 123 HU vs. 473 ± 117 HU; p=0.648). CONCLUSION: In patients with a low heart rate who are not able to hold their breath adequately, CCTA can also be acquired during free breathing without substantial loss of image quality when using a high pitch scan mode in 2nd generation dual-source CT.