Sample size calculation for clinical trials using magnetic resonance imaging for the quantitative assessment of carotid atherosclerosis

Tobias Saam, William S. Kerwin, Baocheng Chu, Jianming Cai, Annette Kampschulte, Thomas S. Hatsukami, Xue Qiao Zhao, Nayak L. Polissar, Blazej Neradilek, Vasily L. Yarnykh, Kelly Flemming, John Huston, William Insull, Joel D. Morrisett, Scott D. Rand, Kevin J. Demarco, Chun Yuan

Research output: Contribution to journalArticle

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Abstract

Purpose. To provide sample size calculation for the quantitative assessment of carotid atherosclerotic plaque using non-invasive magnetic resonance imaging in multi-center clinical trials. Methods. As part of a broader double-blind randomized trial of an experimental pharmaceutical agent, 20 asymptomatic placebo-control subjects were recruited from 5 clinical sites for a multi-center study. Subjects had 4 scans in 13 weeks on GE 1.5 T scanners, using TOF, T1-/PD-/T2- and contrast-enhanced T1-weighted images. Measurement variability was assessed by comparing quantitative data from the index carotid artery over the four time points. The wall/outer wall (W/OW) ratio was calculated as wall volume divided by outer wall volume. The percent lipid-rich/necrotic core (%LR/NC) and calcification (%Ca) were measured as a proportion of the vessel wall. For %LR/NC and %Ca, only those subjects that exhibited LR/NC or Ca components were used in the analysis. Results. Measurement error was 5.8% for wall volume, 3.2% for W/OW ratio, 11.1% for %LR/NC volume and 18.6% for %Ca volume. Power analysis based on these values shows that a study with 14 participants in each group could detect a 5% change in W/OW ratio, 10% change in wall volume, and 20% change in %LR/NC volume (power = 80%, p < .05). The calculated measurement errors presume any true biological changes were negligible over the 3 months that subjects received placebo. Conclusion. In vivo MRI is capable of quantifying plaque volume and plaque composition, such as %lipid-rich/necrotic core and %calcification, in the clinical setting of a multi-center trial with low inter-scan variability. This study provides the basis for sample size calculation of future MRI trials.

Original languageEnglish (US)
Pages (from-to)799-808
Number of pages10
JournalJournal of Cardiovascular Magnetic Resonance
Volume7
Issue number5
DOIs
StatePublished - Oct 2005

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Carotid Artery Diseases
Sample Size
Placebos
Magnetic Resonance Imaging
Clinical Trials
Lipids
Atherosclerotic Plaques
Carotid Arteries
Pharmaceutical Preparations

Keywords

  • Atherosclerosis
  • Carotid arteries
  • Magnetic resonance imaging

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine
  • Radiology Nuclear Medicine and imaging
  • Radiological and Ultrasound Technology
  • Family Practice

Cite this

Sample size calculation for clinical trials using magnetic resonance imaging for the quantitative assessment of carotid atherosclerosis. / Saam, Tobias; Kerwin, William S.; Chu, Baocheng; Cai, Jianming; Kampschulte, Annette; Hatsukami, Thomas S.; Zhao, Xue Qiao; Polissar, Nayak L.; Neradilek, Blazej; Yarnykh, Vasily L.; Flemming, Kelly; Huston, John; Insull, William; Morrisett, Joel D.; Rand, Scott D.; Demarco, Kevin J.; Yuan, Chun.

In: Journal of Cardiovascular Magnetic Resonance, Vol. 7, No. 5, 10.2005, p. 799-808.

Research output: Contribution to journalArticle

Saam, T, Kerwin, WS, Chu, B, Cai, J, Kampschulte, A, Hatsukami, TS, Zhao, XQ, Polissar, NL, Neradilek, B, Yarnykh, VL, Flemming, K, Huston, J, Insull, W, Morrisett, JD, Rand, SD, Demarco, KJ & Yuan, C 2005, 'Sample size calculation for clinical trials using magnetic resonance imaging for the quantitative assessment of carotid atherosclerosis', Journal of Cardiovascular Magnetic Resonance, vol. 7, no. 5, pp. 799-808. https://doi.org/10.1080/10976640500287703
Saam, Tobias ; Kerwin, William S. ; Chu, Baocheng ; Cai, Jianming ; Kampschulte, Annette ; Hatsukami, Thomas S. ; Zhao, Xue Qiao ; Polissar, Nayak L. ; Neradilek, Blazej ; Yarnykh, Vasily L. ; Flemming, Kelly ; Huston, John ; Insull, William ; Morrisett, Joel D. ; Rand, Scott D. ; Demarco, Kevin J. ; Yuan, Chun. / Sample size calculation for clinical trials using magnetic resonance imaging for the quantitative assessment of carotid atherosclerosis. In: Journal of Cardiovascular Magnetic Resonance. 2005 ; Vol. 7, No. 5. pp. 799-808.
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abstract = "Purpose. To provide sample size calculation for the quantitative assessment of carotid atherosclerotic plaque using non-invasive magnetic resonance imaging in multi-center clinical trials. Methods. As part of a broader double-blind randomized trial of an experimental pharmaceutical agent, 20 asymptomatic placebo-control subjects were recruited from 5 clinical sites for a multi-center study. Subjects had 4 scans in 13 weeks on GE 1.5 T scanners, using TOF, T1-/PD-/T2- and contrast-enhanced T1-weighted images. Measurement variability was assessed by comparing quantitative data from the index carotid artery over the four time points. The wall/outer wall (W/OW) ratio was calculated as wall volume divided by outer wall volume. The percent lipid-rich/necrotic core ({\%}LR/NC) and calcification ({\%}Ca) were measured as a proportion of the vessel wall. For {\%}LR/NC and {\%}Ca, only those subjects that exhibited LR/NC or Ca components were used in the analysis. Results. Measurement error was 5.8{\%} for wall volume, 3.2{\%} for W/OW ratio, 11.1{\%} for {\%}LR/NC volume and 18.6{\%} for {\%}Ca volume. Power analysis based on these values shows that a study with 14 participants in each group could detect a 5{\%} change in W/OW ratio, 10{\%} change in wall volume, and 20{\%} change in {\%}LR/NC volume (power = 80{\%}, p < .05). The calculated measurement errors presume any true biological changes were negligible over the 3 months that subjects received placebo. Conclusion. In vivo MRI is capable of quantifying plaque volume and plaque composition, such as {\%}lipid-rich/necrotic core and {\%}calcification, in the clinical setting of a multi-center trial with low inter-scan variability. This study provides the basis for sample size calculation of future MRI trials.",
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T1 - Sample size calculation for clinical trials using magnetic resonance imaging for the quantitative assessment of carotid atherosclerosis

AU - Saam, Tobias

AU - Kerwin, William S.

AU - Chu, Baocheng

AU - Cai, Jianming

AU - Kampschulte, Annette

AU - Hatsukami, Thomas S.

AU - Zhao, Xue Qiao

AU - Polissar, Nayak L.

AU - Neradilek, Blazej

AU - Yarnykh, Vasily L.

AU - Flemming, Kelly

AU - Huston, John

AU - Insull, William

AU - Morrisett, Joel D.

AU - Rand, Scott D.

AU - Demarco, Kevin J.

AU - Yuan, Chun

PY - 2005/10

Y1 - 2005/10

N2 - Purpose. To provide sample size calculation for the quantitative assessment of carotid atherosclerotic plaque using non-invasive magnetic resonance imaging in multi-center clinical trials. Methods. As part of a broader double-blind randomized trial of an experimental pharmaceutical agent, 20 asymptomatic placebo-control subjects were recruited from 5 clinical sites for a multi-center study. Subjects had 4 scans in 13 weeks on GE 1.5 T scanners, using TOF, T1-/PD-/T2- and contrast-enhanced T1-weighted images. Measurement variability was assessed by comparing quantitative data from the index carotid artery over the four time points. The wall/outer wall (W/OW) ratio was calculated as wall volume divided by outer wall volume. The percent lipid-rich/necrotic core (%LR/NC) and calcification (%Ca) were measured as a proportion of the vessel wall. For %LR/NC and %Ca, only those subjects that exhibited LR/NC or Ca components were used in the analysis. Results. Measurement error was 5.8% for wall volume, 3.2% for W/OW ratio, 11.1% for %LR/NC volume and 18.6% for %Ca volume. Power analysis based on these values shows that a study with 14 participants in each group could detect a 5% change in W/OW ratio, 10% change in wall volume, and 20% change in %LR/NC volume (power = 80%, p < .05). The calculated measurement errors presume any true biological changes were negligible over the 3 months that subjects received placebo. Conclusion. In vivo MRI is capable of quantifying plaque volume and plaque composition, such as %lipid-rich/necrotic core and %calcification, in the clinical setting of a multi-center trial with low inter-scan variability. This study provides the basis for sample size calculation of future MRI trials.

AB - Purpose. To provide sample size calculation for the quantitative assessment of carotid atherosclerotic plaque using non-invasive magnetic resonance imaging in multi-center clinical trials. Methods. As part of a broader double-blind randomized trial of an experimental pharmaceutical agent, 20 asymptomatic placebo-control subjects were recruited from 5 clinical sites for a multi-center study. Subjects had 4 scans in 13 weeks on GE 1.5 T scanners, using TOF, T1-/PD-/T2- and contrast-enhanced T1-weighted images. Measurement variability was assessed by comparing quantitative data from the index carotid artery over the four time points. The wall/outer wall (W/OW) ratio was calculated as wall volume divided by outer wall volume. The percent lipid-rich/necrotic core (%LR/NC) and calcification (%Ca) were measured as a proportion of the vessel wall. For %LR/NC and %Ca, only those subjects that exhibited LR/NC or Ca components were used in the analysis. Results. Measurement error was 5.8% for wall volume, 3.2% for W/OW ratio, 11.1% for %LR/NC volume and 18.6% for %Ca volume. Power analysis based on these values shows that a study with 14 participants in each group could detect a 5% change in W/OW ratio, 10% change in wall volume, and 20% change in %LR/NC volume (power = 80%, p < .05). The calculated measurement errors presume any true biological changes were negligible over the 3 months that subjects received placebo. Conclusion. In vivo MRI is capable of quantifying plaque volume and plaque composition, such as %lipid-rich/necrotic core and %calcification, in the clinical setting of a multi-center trial with low inter-scan variability. This study provides the basis for sample size calculation of future MRI trials.

KW - Atherosclerosis

KW - Carotid arteries

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