Optimized Enhancement in Helical CT: Experiences With a Real-Time Bolus Tracking System in 628 Patients

• Published in: Clinical radiology Vol. 55; no. 5; pp. 368 - 373
• Main Authors: KIRCHNER, J., KICKUTH, R., LAUFER, U., NOACK, M., LIERMANN, D.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Ltd 01.05.2000; Elsevier
• Subjects: Abdominal Neoplasms - diagnostic imaging; Adult; Aged; Aged, 80 and over; Biological and medical sciences; computed tomography, helical CT, contrast medium enhancement, bolus triggering; Contrast Media - administration & dosage; Drug Administration Schedule; Female; Humans; Investigative techniques, diagnostic techniques (general aspects); Male; Medical sciences; Middle Aged; Miscellaneous. Technology; Prospective Studies; Pulmonary Embolism - diagnostic imaging; Radiodiagnosis. Nmr imagery. Nmr spectrometry; Sex Factors; Thoracic Neoplasms - diagnostic imaging; Tomography, X-Ray Computed - methods; computed tomography, helical CT, contrast medium enhancement, bolus triggering; Human; Prospective; Radiodiagnosis; Technology; Medical imagery; Helical structure; Thorax; Computerized axial tomography; Diagnosis; Technique; Contrast media; Abdomen
• ISSN: 0009-9260; 1365-229X
• DOI: 10.1053/crad.2000.0376

AIMS: Ultrafast detector technology enables bolus-triggered application of contrast media. In a prospective study we investigated the benefit of this new method with the intention of optimizing enhancement during examination of the chest and abdomen. MATERIALS AND METHODS: In total, we examined 548 patients under standardized conditions. All examinations were performed on a Somatom Plus 4 Power CT system (Siemens Corp., Forchheim, Germany) using the CARE-Bolus software. This produces repetitive low-dose test images (e.g. for the lung: 140kV, 43mA, TI 0.5s) and measures the Hounsfield attenuation in a pre-selected region of interest. After exceeding a defined threshold, a diagnostic spiral CT examination was begun automatically. The data obtained from 321 abdominal CT and 179 lung CT examinations were correlated with different parameters such as age, weight and height of the patients and parameters of vascular access. In a group of 80 patients, the injection of contrast medium was stopped after reaching a pre-defined threshold of an increase of 100HU over the baseline. Then, we assessed the maximal enhancement of liver, pulmonal artery trunk and aortic arch. RESULTS: There was no correlation between bolus geometry and age, body surface or weight. In helical CT of the abdomen the threshold was reached after a mean trigger time of 27s (range 13–67s) and only 65ml (range 41–105ml) of contrast medium were administered. In helical CT of the lung the threshold was reached after 21s (range 12–48s) and the mean amount of administered contrast medium was 48ml (range 38–71ml). CONCLUSION: Bolus triggering allows optimized enhancement of the organs and reduces the dose of contrast material required compared with standard administration.Kirchner, J. (2000). Clinical Radiology55, 368–373.