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

Abstract

The aim of this study was to determine if a saline solution flush following low dose contrast material bolus improves parenchymal and vascular enhancement during abdominal multiple detector-row computed tomography (MDCT). Forty-one patients (24 men and 17 women; mean age 49 years, age range 27-86 years) underwent abdominal MDCT (collimation 4x5 mm, 15-mm table increment, reconstruction interval 5 mm, gantry rotation period 0.8 s) with a single- as well as with a double syringe power injector. Indication for examination were benign and malignant tumors and inflammatory diseases. Patients received 100 ml nonionic contrast material (300 mgI/ml) alone or pushed with 20 ml saline solution. Mean enhancement values for both protocols were measured in the liver, the spleen, the pancreas, the renal cortex, the portal vein, the inferior vena cava and the abdominal aorta. Double syringe power-injector protocol led to significantly higher parenchymal and vascular enhancement than single syringe power-injector protocol (p<0.05). The improvement in mean enhancement of the liver was 9 +/- 9 HU, of the spleen 8 +/- 10 HU, of the pancreas 7 +/- 9 HU, and of the renal cortex 8 +/- 20 HU. The improvement in mean enhancement of the portal vein was 10 +/- 17 HU of the inferior vena cava 8 +/- 13 HU and of the abdominal aorta 10 +/- 17 HU. The use of a double syringe power injector with saline flush following contrast material bolus significantly improves parenchymal and vascular enhancement during contrast-enhanced abdominal MDCT with low iodine doses.

Spiral Flow Tube for Saline Flush in Coronary CT Angiography: Initial Experience

“…By pushing this residual contrast medium into the central venous system, a saline flush could achieve a reduction of 12 mL [15] or 10% dose of contrast medium [3,11] with maintained arterial enhancement in the arterial phase. Other studies showed that saline flush increased the enhancement of coronary arteries [3] and aorta [10] by 10%. Saline flush could also reduce streak artifacts from the superior vena cava by washing out the excessive contrast medium [3,12] .…”

“…Saline flush is also used in imaging the aorta [10][11][12] and carotid arteries [13] . A previous study showed that approximately 10 to 20 mL of contrast medium remained in the brachial vein or the superior vena cava without saline flush [14] .…”

Triphasic Contrast Agent Injection in 64-MDCT Coronary Artery Angiography

“…The biphasic injection protocol was developed to overcome some of these shortcomings. Studies on the efficacy of biphasic injection protocol have demonstrated substantial improvement in image quality over the monophasic protocol, providing excellent coronary artery enhancement with less contrast-related streak artifacts in the SVC 22,23 . However, in many patients, the saline chaser bolus flushes contrast in the right cardiac chambers so effectively that it is unable to discern the internal structures (valve, papillary muscles, etc.)…”

64-section multidetector CT of the upper abdomen: optimization of a saline chaser injection protocol for improved vascular and parenchymal contrast enhancement

“…By pushing the tail of the injected contrast medium bolus, a saline chaser prevents pooling of contrast material in the peripheral venous compartment at the injection site and in the injection tubing, increasing the effectiveness of contrast material utilization [3]. The increased efficiency provided by a saline chaser can be exploited clinically to: (i) decrease the volume of contrast material (typically by 20-30 mL) without jeopardizing vascular and parenchymal enhancement [4][5][6][7][8][9], (ii) increase the magnitude of enhancement (by 5%-10%) using a standard dose of contrast material [10][11][12] or (iii), as recently advocated [13], attain durable and uniform peak enhancement during the entire CT acquisition. However, although the advantages of a saline chaser for optimizing CT contrast enhancement are widely accepted, disagreement remains over the most effective injection protocol for the administration of saline [14][15][16].…”