Abstract
Objectives:To perform CT pulmonary angiography (CTPA) using a minimal amount of iodinated contrast media.Methods:47 patients (25 females) with mean age 69 years (range 41–82 years) referred for contrast-enhanced chest CT were prospectively included in this Phase IV clinical drug trial. All participants underwent a study specific CTPA in addition to the chest CT. The participants received 80 mg I/kg body weight Iohexol contrast media using a preparatory saline bolus, a dual flow contrast/saline bolus and a saline flush, and a scanner protocol with 80 kVp dual source high-pitch mode. Three readers independently assessed the image quality on the 3-point scale non-diagnostic, adequate or good-excellent image quality. Additionally, the pulmonary arterial contrast opacification was measured.Results:On average, the patients received 16.8 ml Iohexol 350 mg I/mL (range 12–20 ml). Mean patient weight was 71 kg (range 50–85 kg). Identically for all readers, pulmonary embolism (PE) was detected in 1/47 participants. The median number of examinations visually scored concerning pulmonary embolism as good–excellent was 47/47 (range 44–47); adequate 0/47 (0–3) and non-diagnostic 0/47 (range 0–0). The proportion adequate or better examinations was for all readers 47/47, 100% [95% confidence interval 92–100%]. The mean attenuation ± standard deviation in the pulmonary trunk was 325 ± 72 Hounsfield unit (range 165–531 Hounsfield unit).Conclusions:Diagnostic CTPA with 17 ml contrast media is possible in non-obese patients using low kVp, high pitch and carefully designed contrast media administration.Advances in knowledge:By combining several procedures in a CTPA protocol, the contrast media dose can be minimized.
Highlights
Pulmonary embolism (PE) is a common condition with high mortality and morbidity.[1,2] Since the 1990s, CT pulmonary angiography (CTPA) has become the method of choice for imaging in suspected PE.[2,3,4] CTPA is a standard procedure that obtains a CT volume while intravenously injected iodinated contrast media (CM) opacifies the pulmonary arteries.Recent guidelines conclude that the risk of post-contrast acute kidney injury (PC-AKI) is lower than previously believed, but does exist, especially for patients with severely impaired renal function.[5]
CTPA examinations were successfully performed with no adverse events in all 47 subjects
For all readers, PE was detected in 1/47 participants
Summary
Pulmonary embolism (PE) is a common condition with high mortality and morbidity.[1,2] Since the 1990s, CT pulmonary angiography (CTPA) has become the method of choice for imaging in suspected PE.[2,3,4] CTPA is a standard procedure that obtains a CT volume while intravenously injected iodinated contrast media (CM) opacifies the pulmonary arteries. Recent guidelines conclude that the risk of post-contrast acute kidney injury (PC-AKI) is lower than previously believed, but does exist, especially for patients with severely impaired renal function.[5] For patients at risk for PC-A KI, lowering the CM dose is preferable[6,7,8] but the image quality needs to be maintained. The increased attenuation of iodine in low-k Vp CT protocols is used to reduce the amount of CM administered in CTPA.[9,10,11,12,13,14,15,16,17]
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