American Journal of Roentgenology, Vol 164, 619-623, Copyright © 1995 by American Roentgen Ray Society

ARTICLES

Conspicuity of hepatic metastases on helical CT: effect of different time delays between contrast administration and scanning

PM Silverman, J O'Malley, MC Tefft, C Cooper and RK Zeman
Department of Radiology, Georgetown University Medical Center, Washington, DC 20007.

OBJECTIVE. The purpose of this study was to compare two time delays between injection of contrast material and helical CT scanning to determine relative conspicuity of hepatic metastases. SUBJECTS AND METHODS. Twenty-five patients with hepatic metastases were examined with helical CT. The first imaging phase was initiated at 50 sec and the second 75 sec after the start of contrast material injection (3 ml/sec, 150 ml). Differences in lesion and liver attenuation were measured quantitatively. Four radiologists used a 5-point scale to assess lesion conspicuity subjectively. RESULTS. Mean differences in enhancement between liver and lesion were 41 H during the first phase and 59 H for the second phase (p = .0001). Radiologists' conspicuity score averaged 2.4 for lesions in the first phase versus 3.3 for lesions in the second phase (p = .0001). In 56 (88%) of 64 lesions, objective measurements showed greater enhancement of lesions during the later phase. Radiologists found 60 (94%) of 64 lesions to be more conspicuous on these later images. CONCLUSION. Our results show that conspicuity of hepatic metastases on helical CT scans is better with a 75-sec scan delay between contrast administration and scanning than with a 50-sec scan delay. The longer delay time should be used when scanning is used to detect metastases.
CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

This article has been cited by other articles:

				L. L. Chu, B. N. Joe, A. C. A. Westphalen, E. M. Webb, F. V. Coakley, and B. M. Yeh Patient-specific Time to Peak Abdominal Organ Enhancement Varies with Time to Peak Aortic Enhancement at MR Imaging Radiology, December 1, 2007; 245(3): 779 - 787. [Abstract] [Full Text] [PDF]

				S. Monzawa, T. Ichikawa, H. Nakajima, Y. Kitanaka, K. Omata, and T. Araki Dynamic CT for Detecting Small Hepatocellular Carcinoma: Usefulness of Delayed Phase Imaging Am. J. Roentgenol., January 1, 2007; 188(1): 147 - 153. [Abstract] [Full Text] [PDF]

				K. Awai, K. Hiraishi, and S. Hori Effect of Contrast Material Injection Duration and Rate on Aortic Peak Time and Peak Enhancement at Dynamic CT Involving Injection Protocol with Dose Tailored to Patient Weight Radiology, January 1, 2004; 230(1): 142 - 150. [Abstract] [Full Text] [PDF]

				K. Awai, K. Takada, H. Onishi, and S. Hori Aortic and Hepatic Enhancement and Tumor-to-Liver Contrast: Analysis of the Effect of Different Concentrations of Contrast Material at Multi-Detector Row Helical CT Radiology, September 1, 2002; 224(3): 757 - 763. [Abstract] [Full Text] [PDF]

				J. H. Lim, D. Choi, S. H. Kim, S. J. Lee, W. J. Lee, H. K. Lim, and S. Kim Detection of Hepatocellular Carcinoma: Value of Adding Delayed Phase Imaging to Dual-Phase Helical CT Am. J. Roentgenol., July 1, 2002; 179(1): 67 - 73. [Abstract] [Full Text] [PDF]

				K. Wong, E. K. Paulson, and R. C. Nelson Breath-hold Three-dimensional CT of the Liver with Multi-Detector Row Helical CT Radiology, April 1, 2001; 219(1): 75 - 79. [Abstract] [Full Text]

				B. S. Kuszyk, D. A. Bluemke, M. A. Choti, K. M. Horton, C. A. Magee, and E. K. Fishman Contrast-Enhanced CT of Small Hypovascular Hepatic Tumors: Effect of Lesion Enhancement on Conspicuity in Rabbits Am. J. Roentgenol., February 1, 2000; 174(2): 471 - 0. [Abstract] [Full Text] [PDF]

				T. Kim, T. Murakami, S. Takahashi, A. Okada, M. Hori, Y. Narumi, and H. Nakamura Pancreatic CT Imaging: Effects of Different Injection Rates and Doses of Contrast Material Radiology, July 1, 1999; 212(1): 219 - 225. [Abstract] [Full Text]