Dataset Information

Ultrasound settings significantly alter arterial lumen and wall thickness measurements.

ABSTRACT:

Background

Flow-mediated dilation (FMD) and carotid intima-medial thickness (CIMT), measured by ultrasound, are widely used to test the efficacy of cardioprotective interventions. Although assessment methods vary, automated edge-detecting image analysis software is routinely used to measure changes in FMD and CIMT. We aimed to quantify the effect that commonly adjusted ultrasound settings have on arterial lumen and wall thickness measurements made with CIMT measurement software.

Methods

We constructed phantom arteries from a tissue-mimicking agar compound and scanned them in a water bath with a 10 MHz multi-frequency linear-array probe attached to a high-resolution ultrasound machine. B-mode images of the phantoms were recorded with dynamic range (DR) and gain set at five decibel (dB) increments from 40 dB to 60 dB and -10 dB to +10 dB respectively. Lumen diameter and wall-thickness were measured off-line using CIMT measurement software.

Results

Lumen measurements: there was a strong linear relationship between DR and gain and measured lumen diameter. For a given gain level, a 5 dB increase in DR reduced the measured lumen diameter by 0.02 +/- 0.004 mm (p < 0.001). For a given DR level, a 5 dB increase in gain reduced measured lumen diameter by 0.04 +/- 0.004 mm (p < 0.001). A 5 mm increase in distance between the ultrasound probe and the artery reduced measured lumen diameter by 0.04 +/- 0.03 mm (p < 0.001)CIMT measurements: For a fixed gain level, a 5 dB increase in DR increased measured wall thickness by 0.003 +/- 0.002 mm (p < 0.001). The effects of increasing gain were not consistent and appeared to vary depending on the distance between the artery and the ultrasound probe and the thickness of the artery wall.

Conclusion

DR, gain and probe distance significantly alter lumen diameter and CIMT measurements made using image analysis software. When CIMT and FMD are used to test the efficacy of cardioprotective interventions, the DR, gain and probe position used to record baseline scans should be documented and replicated in post-treatment scans in individual trial subjects. If more than one sonographer or imaging centre is used to collect data, the study protocol should document specific DR and gain settings to be used in all subjects.

SUBMITTER: Potter K

PROVIDER: S-EPMC2254584 | biostudies-literature | 2008 Jan

REPOSITORIES: biostudies-literature

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Ultrasound settings significantly alter arterial lumen and wall thickness measurements.

Potter Kathleen K Reed Christopher J CJ Green Daniel J DJ Hankey Graeme J GJ Arnolda Leonard F LF

Cardiovascular ultrasound 20080122

<h4>Background</h4>Flow-mediated dilation (FMD) and carotid intima-medial thickness (CIMT), measured by ultrasound, are widely used to test the efficacy of cardioprotective interventions. Although assessment methods vary, automated edge-detecting image analysis software is routinely used to measure changes in FMD and CIMT. We aimed to quantify the effect that commonly adjusted ultrasound settings have on arterial lumen and wall thickness measurements made with CIMT measurement software.<h4>Metho ...[more]

PMID: 18208623

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Project description:Introduction: Despite improved therapies and management, patients with systemic lupus erythematosus (SLE) still have increased risks of cerebrovascular and cardiovascular disease. High-frequency ultrasound (US) provides an opportunity to distinguish atherosclerosis from inflammation in the vessels. We hypothesized that an extended US protocol may add information regarding vascular affection in SLE. Methods: Sixty patients (52 women, 8 men; mean age 43.2 ± 11.3 years) with SLE characterized by either lupus nephritis (LN; n = 20), antiphospholipid syndrome (APS; n = 20), or skin and joint involvement (n = 20) as well as matched healthy controls (n = 60) were included. Intima-media thickness (IMT), assessment of vessel walls, and plaque occurrence were recorded using high-frequency US (GE Logic E9) in common carotid, internal carotid, brachiocephalic, subclavian, axillary, common femoral, and proximal superficial femoral arteries as well as in the aortic arch. Results: For the entire SLE group, IMT was increased in the internal carotid artery (0.52 ± 0.17 vs. 0.45 ± 0.09 mm, p = 0.004), the common femoral artery (0.57 ± 0.23 vs. 0.49 ± 0.11 mm, p < 0.01), the subclavian artery (0.58 ± 0.19 vs. 0.53 ± 0.13 mm, p = 0.02), and the aortic arch (1.21 ± 0.63 vs. 0.98 ± 0.25 mm, p = 0.002) compared to controls. These differences were primarily observed in the APS and LN groups compared to controls. Vessels with increased IMT ≥0.9 mm had a smooth, medium echogenic appearance in areas free of atherosclerotic plaques. Atherosclerotic plaques were detected in 15/60 patients (25%) as compared to 2/60 of the controls (3%). Plaques were predominantly (67%) located in the carotid bifurcation. Multivariate analysis revealed influence of age on IMT in all vessel areas. Furthermore, in the common femoral artery, sagittal abdominal diameter, diastolic blood pressure, and cholesterol all showed association with increased IMT. In the internal carotid artery, male sex and presence of Raynaud phenomenon influenced IMT. Conclusion: Among SLE patients without presence of plaques, an extended US protocol revealed increased wall thickness with predominantly medium echogenic appearance highlighting possibly inflammation or early atherosclerosis. The appearance of vessel walls has not previously been studied in detail. An increased number of plaques were found in SLE compared to age- and sex-matched healthy controls. We found similar risk factors for increased IMT and occurrence of plaques, possibly indicating atherosclerotic mechanisms rather than inflammation.

Project description:In the current study, we aimed to determine the association of single nucleotide polymorphism rs189037 in ataxia-telangiectasia mutated (ATM) gene with cardiac structure and human longevity. Based on the China Hainan Centenarian Cohort Study performed in 18 cities and counties of Hainan Province, China, the current study enrolled 547 centenarians, 250 young participants aged 20-45 years, and 250 middle-aged and elderly participants aged 46-90 years. The frequency of TT genotype was significantly higher and that of CC genotype was significantly lower in middle-aged and elderly participants than in young (P = 0.012) and centenarian (P = 0.041) participants. There were no significant differences in the genotype and allele frequencies of SNP rs189037 between young and centenarian participants. Compared with CT genotype, TT genotype was positively and significantly associated with interventricular septum thickness (IVST) and left ventricular posterior wall thickness (LVPWT) in centenarian (IVST: P = 0.049; LVPWT: P = 0.047) and middle-aged and elderly (IVST: P = 0.008; LVPWT: P = 0.004) participants. Compared with CC genotype, TT genotype was positively and significantly associated with LVPWT in centenarian (P = 0.030) and middle-aged and elderly (P = 0.013) participants. Compared with CC genotype, CT genotype was negatively and significantly associated with left ventricular end-diastolic diameter (LVEDD) in centenarian (P = 0.011) and middle-aged and elderly (P = 0.040) participants. The current study demonstrated that mutant rs189037 in the ATM gene was more commonly identified in middle-aged and elderly participants than in young and centenarian participants, was significantly associated with increased left ventricular wall thickness and volume, and could induce left ventricular eccentric hypertrophy and shorten human lifespan. Therefore, rs189037 without mutation might be an indicator of youth health and successful aging, whereas mutant rs189037 might hinder human longevity.

Dataset Information

Ultrasound settings significantly alter arterial lumen and wall thickness measurements.

Background

Methods

Results

Conclusion

Publications

Ultrasound settings significantly alter arterial lumen and wall thickness measurements.

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