Clinical comparison of standard-dose and 50% reduced-dose abdominal CT: Effect on image quality

Mannudeep K. Kalra, Srinivasa Prasad, Sanjay Saini, Michael A. Blake, Jose Varghese, Elkan F. Halpern, James H. Thrall

Research output: Contribution to journalArticle

132 Citations (Scopus)

Abstract

OBJECTIVE. We hypothesized that radiation doses for abdominal CT could be reduced by adjusting the dose for a patient's weight and cross-sectional abdominal dimensions, with the resultant scans still being of diagnostic quality. SUBJECTS AND METHODS. Using a multidetector CT scanner, we prospectively studied 39 patients who were 65 years and older who had a known history of cancer. After performing a diagnostic contrast-enhanced CT examination, we obtained four slices each (centered at the top of the right kidney) at a standard radiation dose (240-300 mA) and at a 50% reduced dose (120-150 mA) at a constant kilovoltage of 140. Scans were obtained during a single breath-hold, with a 2.5-mm detector configuration and a slice pitch of 6: 1. Reconstructed slice thickness was 5 mm. In a blinded review, two radiologists rated the randomized CT scans for overall image quality and anatomic details of liver, spleen, adrenal glands, kidneys, pancreas, and abdominal wall, using a 5-point scale (1 = unacceptable, 2 = substandard, 3 = acceptable, 4 = above average, and 5 = superior). Patients' weight and abdominal circumference, area, and anteroposterior and transverse diameters were correlated with image quality of scans obtained at standard-dose and 50% reduced-dose CT. Statistical analysis of the data was performed using Wilcoxon's signed rank test. RESULTS. Overall, the image quality score was significantly higher (p < 0.005) on the scans obtained with standard-dose CT. No statistically significant difference in image quality was noted in the 50% reduced- and standard-dose CT scans in patients who weighed less than 180 lb, or 81 kg, (p > 0.05) and who had a transverse abdominal diameter of less than 34.5 cm (p > 0.05), an anteroposterior diameter of less than 28 cm (p > 0.05), a cross-sectional circumference of less than 105 cm (p > 0.05), and a cross-sectional area of less than 800 cm2 (p > 0.05). Good interobserver agreement (p > 0.5) was found between the two reviewing radiologists. CONCLUSION. Abdominal CT scan quality appears to be acceptable even with a 50% reduction in radiation dose except in patients with large anthropometric measurements. A reduction in CT radiation dose is possible if the tube current is optimized for the patient's weight and abdominal dimensions.

Original languageEnglish (US)
Pages (from-to)1101-1106
Number of pages6
JournalAmerican Journal of Roentgenology
Volume179
Issue number5
StatePublished - Nov 2002

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Radiation
Weights and Measures
Kidney
Abdominal Muscles
Statistical Data Interpretation
Abdominal Wall
Adrenal Glands
Nonparametric Statistics
Pancreas
Spleen
Liver
Neoplasms
Radiologists

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging
  • Radiological and Ultrasound Technology

Cite this

Kalra, M. K., Prasad, S., Saini, S., Blake, M. A., Varghese, J., Halpern, E. F., & Thrall, J. H. (2002). Clinical comparison of standard-dose and 50% reduced-dose abdominal CT: Effect on image quality. American Journal of Roentgenology, 179(5), 1101-1106.

Clinical comparison of standard-dose and 50% reduced-dose abdominal CT : Effect on image quality. / Kalra, Mannudeep K.; Prasad, Srinivasa; Saini, Sanjay; Blake, Michael A.; Varghese, Jose; Halpern, Elkan F.; Thrall, James H.

In: American Journal of Roentgenology, Vol. 179, No. 5, 11.2002, p. 1101-1106.

Research output: Contribution to journalArticle

Kalra, MK, Prasad, S, Saini, S, Blake, MA, Varghese, J, Halpern, EF & Thrall, JH 2002, 'Clinical comparison of standard-dose and 50% reduced-dose abdominal CT: Effect on image quality', American Journal of Roentgenology, vol. 179, no. 5, pp. 1101-1106.
Kalra, Mannudeep K. ; Prasad, Srinivasa ; Saini, Sanjay ; Blake, Michael A. ; Varghese, Jose ; Halpern, Elkan F. ; Thrall, James H. / Clinical comparison of standard-dose and 50% reduced-dose abdominal CT : Effect on image quality. In: American Journal of Roentgenology. 2002 ; Vol. 179, No. 5. pp. 1101-1106.
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abstract = "OBJECTIVE. We hypothesized that radiation doses for abdominal CT could be reduced by adjusting the dose for a patient's weight and cross-sectional abdominal dimensions, with the resultant scans still being of diagnostic quality. SUBJECTS AND METHODS. Using a multidetector CT scanner, we prospectively studied 39 patients who were 65 years and older who had a known history of cancer. After performing a diagnostic contrast-enhanced CT examination, we obtained four slices each (centered at the top of the right kidney) at a standard radiation dose (240-300 mA) and at a 50{\%} reduced dose (120-150 mA) at a constant kilovoltage of 140. Scans were obtained during a single breath-hold, with a 2.5-mm detector configuration and a slice pitch of 6: 1. Reconstructed slice thickness was 5 mm. In a blinded review, two radiologists rated the randomized CT scans for overall image quality and anatomic details of liver, spleen, adrenal glands, kidneys, pancreas, and abdominal wall, using a 5-point scale (1 = unacceptable, 2 = substandard, 3 = acceptable, 4 = above average, and 5 = superior). Patients' weight and abdominal circumference, area, and anteroposterior and transverse diameters were correlated with image quality of scans obtained at standard-dose and 50{\%} reduced-dose CT. Statistical analysis of the data was performed using Wilcoxon's signed rank test. RESULTS. Overall, the image quality score was significantly higher (p < 0.005) on the scans obtained with standard-dose CT. No statistically significant difference in image quality was noted in the 50{\%} reduced- and standard-dose CT scans in patients who weighed less than 180 lb, or 81 kg, (p > 0.05) and who had a transverse abdominal diameter of less than 34.5 cm (p > 0.05), an anteroposterior diameter of less than 28 cm (p > 0.05), a cross-sectional circumference of less than 105 cm (p > 0.05), and a cross-sectional area of less than 800 cm2 (p > 0.05). Good interobserver agreement (p > 0.5) was found between the two reviewing radiologists. CONCLUSION. Abdominal CT scan quality appears to be acceptable even with a 50{\%} reduction in radiation dose except in patients with large anthropometric measurements. A reduction in CT radiation dose is possible if the tube current is optimized for the patient's weight and abdominal dimensions.",
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AU - Kalra, Mannudeep K.

AU - Prasad, Srinivasa

AU - Saini, Sanjay

AU - Blake, Michael A.

AU - Varghese, Jose

AU - Halpern, Elkan F.

AU - Thrall, James H.

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N2 - OBJECTIVE. We hypothesized that radiation doses for abdominal CT could be reduced by adjusting the dose for a patient's weight and cross-sectional abdominal dimensions, with the resultant scans still being of diagnostic quality. SUBJECTS AND METHODS. Using a multidetector CT scanner, we prospectively studied 39 patients who were 65 years and older who had a known history of cancer. After performing a diagnostic contrast-enhanced CT examination, we obtained four slices each (centered at the top of the right kidney) at a standard radiation dose (240-300 mA) and at a 50% reduced dose (120-150 mA) at a constant kilovoltage of 140. Scans were obtained during a single breath-hold, with a 2.5-mm detector configuration and a slice pitch of 6: 1. Reconstructed slice thickness was 5 mm. In a blinded review, two radiologists rated the randomized CT scans for overall image quality and anatomic details of liver, spleen, adrenal glands, kidneys, pancreas, and abdominal wall, using a 5-point scale (1 = unacceptable, 2 = substandard, 3 = acceptable, 4 = above average, and 5 = superior). Patients' weight and abdominal circumference, area, and anteroposterior and transverse diameters were correlated with image quality of scans obtained at standard-dose and 50% reduced-dose CT. Statistical analysis of the data was performed using Wilcoxon's signed rank test. RESULTS. Overall, the image quality score was significantly higher (p < 0.005) on the scans obtained with standard-dose CT. No statistically significant difference in image quality was noted in the 50% reduced- and standard-dose CT scans in patients who weighed less than 180 lb, or 81 kg, (p > 0.05) and who had a transverse abdominal diameter of less than 34.5 cm (p > 0.05), an anteroposterior diameter of less than 28 cm (p > 0.05), a cross-sectional circumference of less than 105 cm (p > 0.05), and a cross-sectional area of less than 800 cm2 (p > 0.05). Good interobserver agreement (p > 0.5) was found between the two reviewing radiologists. CONCLUSION. Abdominal CT scan quality appears to be acceptable even with a 50% reduction in radiation dose except in patients with large anthropometric measurements. A reduction in CT radiation dose is possible if the tube current is optimized for the patient's weight and abdominal dimensions.

AB - OBJECTIVE. We hypothesized that radiation doses for abdominal CT could be reduced by adjusting the dose for a patient's weight and cross-sectional abdominal dimensions, with the resultant scans still being of diagnostic quality. SUBJECTS AND METHODS. Using a multidetector CT scanner, we prospectively studied 39 patients who were 65 years and older who had a known history of cancer. After performing a diagnostic contrast-enhanced CT examination, we obtained four slices each (centered at the top of the right kidney) at a standard radiation dose (240-300 mA) and at a 50% reduced dose (120-150 mA) at a constant kilovoltage of 140. Scans were obtained during a single breath-hold, with a 2.5-mm detector configuration and a slice pitch of 6: 1. Reconstructed slice thickness was 5 mm. In a blinded review, two radiologists rated the randomized CT scans for overall image quality and anatomic details of liver, spleen, adrenal glands, kidneys, pancreas, and abdominal wall, using a 5-point scale (1 = unacceptable, 2 = substandard, 3 = acceptable, 4 = above average, and 5 = superior). Patients' weight and abdominal circumference, area, and anteroposterior and transverse diameters were correlated with image quality of scans obtained at standard-dose and 50% reduced-dose CT. Statistical analysis of the data was performed using Wilcoxon's signed rank test. RESULTS. Overall, the image quality score was significantly higher (p < 0.005) on the scans obtained with standard-dose CT. No statistically significant difference in image quality was noted in the 50% reduced- and standard-dose CT scans in patients who weighed less than 180 lb, or 81 kg, (p > 0.05) and who had a transverse abdominal diameter of less than 34.5 cm (p > 0.05), an anteroposterior diameter of less than 28 cm (p > 0.05), a cross-sectional circumference of less than 105 cm (p > 0.05), and a cross-sectional area of less than 800 cm2 (p > 0.05). Good interobserver agreement (p > 0.5) was found between the two reviewing radiologists. CONCLUSION. Abdominal CT scan quality appears to be acceptable even with a 50% reduction in radiation dose except in patients with large anthropometric measurements. A reduction in CT radiation dose is possible if the tube current is optimized for the patient's weight and abdominal dimensions.

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