Eighty-peak kilovoltage 16-channel multidetector computed tomography and reduced contrast-medium doses tailored to body weight to diagnose pulmonary embolism in azotaemic patients

Abstract

The aim of this study was to assess the feasibility of minimising contrast-medium (CM) doses using 80-peak kilovoltage (kVp) 16-channel multidetector computed tomography (MDCT) with CM dose tailored to body weight, when diagnosing pulmonary embolism (PE) in azotaemic patients. Twenty-nine patients (68-93 years; 38-79 kg) with an estimated glomerular filtration rate of 12-49 ml/min underwent 80 kVp MDCT at a median dose of 200 mg iodine (I)/kg and 15 s injection time. Pulmonary artery (PA) enhancement where compared with our own reference material using 320 mg I/kg at 120 kVp and with reported figures in the literature at 120-140 kVp and a 42 g iodine CM dose. Median (1st and 3rd quartiles) values regarding CM dose were 12.2 (9.9-12.8) g iodine; density of left main and lower lobe segmental PA 339 (275-395) Hounsfield units (HU) and 354 (321-442) HU, respectively. Those enhancement values were similar to those obtained from the reference population at 120 kVp and those reported in the literature at 120-140 kVp. One patient had a transient increase in plasma creatinine. Three months' follow-up revealed deep venous thrombosis among 1/18 patients with negative results from computed tomography (CT). We conclude that 80 kVp 16-channel MDCT to diagnose PE in azotaemic patients may be performed with markedly reduced CM doses, implying a lesser risk for CM-induced nephropathy.

Ultralow contrast medium doses at CT to diagnose pulmonary embolism in patients with moderate to severe renal impairment: a feasibility study

“…The present CM doses, ranging from 6-12 g iodine at 80 kVp, resulted in the same PA density as that reported when using 120-140 kVp and non-individualised 24-42 g of iodine doses with 16-MDCT [9,[24][25][26]. Traditional doses at 120-140 kVp may correspond to about 500 mg I/kg [26].…”

“…Traditional doses at 120-140 kVp may correspond to about 500 mg I/kg [26]. A recent study indicated that 400 mg I/kg is required using a 16-MDCT at 120 kVp to reach a PA density of about 300 HU, which was regarded adequate for assessing the diagnosis of PE [25].…”

High-pitch dual-source CT angiography without ECG-gating for imaging the whole aorta: intraindividual comparison with standard pitch single-source technique without ECG-gating

“…In particular, we observed increased aortic attenuation in DS-CTA images, which were acquired with lower tube voltage. This advantage is readily explained by the application of 100 kVp, which is closer to the K-edge of iodine and enables better interaction than higher potentials, such as those used for standard CTA (14). The increased aortic attenuation might contribute to increased diagnostic confidence (e.g., depiction and characterization of parietal thrombus) along with reduction of motion artifacts achieved by the higher temporal resolution (15).…”

Is body weight the most appropriate criterion to select patients eligible for low-dose pulmonary CT angiography? Analysis of objective and subjective image quality at 80 kVp in 100 patients

“…The method is especially interesting for use with the chest, where the increase in image noise at low kilovoltage is less pronounced due to the low x-ray absorption of the lungs [4]. Clinical studies have already confirmed the practicability of 100 kVp pulmonary CTA protocols to provide a good contrast-to-noise ratio (CNR) and subjective image quality at a reduced radiation dose, as compared to 120 and 140 kVp [5,6].…”