Hepatic helical CT: effect of reduction of iodine dose of intravenous contrast material on hepatic contrast enhancement.

Abstract

Decrease in iodine dose from 45-48 g to 30-32 g significantly decreases all HCE values, which potentially decreases detection of focal hypovascular hepatic lesions.

Improvement of parenchymal and vascular enhancement using saline flush and power injection for multiple-detector-row abdominal CT

“…This enhancement was achieved with an iodine dose of 38 g in 70% of heavy patients (>83 kg) and with an iodine dose of 26 g in 70% of thin patients (<83 kg). Conversely, Freeny et al [9] reported that a reduction of iodine dose from 45-48 to 30-32 g results in an average decrease of hepatic enhancement by 18 HU or 27%, which potentially decreases detection of focal hypovascular hepatic lesions. Megibow et al [10] achieved hepatic enhancement above the standard of 30 HU over baseline with a standard dose of 1.5 ml/kg (using Iopromide 300).…”

“…A statistically significant improvement in mean parenchymal enhancement of 8 HU was achieved by flushing a 100-ml contrast-material bolus with 20 ml saline solution. Consequently, the decrease of parenchymal enhancement resulting from contrast material dose reduction (decrease of 18 HU by reducing from 45-48 to 30-32 iodine dose as shown by Freeny et al [9]) could partly be compensated by flushing with saline solution in clinical routine. An increased aortic enhancement of 10 HU, as achieved in our study, may improve the detection of dissection flaps, thrombotic material, and atherosclerotic soft plaques in the abdominal aorta and its branches; however, a positive effect of saline flush on vascular enhancement may be more clinically relevant in abdominal CTA.…”

“…Previous investigations have provided information about the effect of different doses of intravenous contrast material in helical CT of the abdomen and especially of the liver and about the minimum volume of intravenous contrast material required for abdominal CT [9,10,12,13,14,15,16,17,18]. Bluemke et al [8], extrapolating from rabbit data, determined that a dose of 429 mgI/kg (using Iohexol 300) is the lowest dose to produce a hepatic enhancement of 30 HU, which is a low threshold of acceptability.…”

“…In addition, dose reduction is also advantageous in patients with renal insufficiency and/or patients who require additional contrast material for other radiological examinations in close temporal proximity to abdominal CT. On the other hand, reduction of contrast material dose in abdominal CT results in a decrease of hepatic enhancement, which potentially decreases detection of hypovascular or hypervascular hepatic lesions; therefore, several authors have established lower limits to which contrast material could be reduced [8,9,10].…”

Selective use of low-osmolality contrast media in computed tomography

“…The initial hope that helical-CT technology would allow a reduction of the dose of contrast has not been conclusively proved. On the contrary, Freeny and coworkers have shown that decreasing the volume of contrast in hepatic CT from 150 to 100 ml results in a significant reduction of hepatic contrast enhancement [17]. As the detection of liver lesions by CT depends on the different attenuation values between focal lesions and normal parenchyma, this imaging strategy may potentially result in missing small lesions.…”