Dose and Pitch Relationship for a Particular Multislice CT Scanner

Mahesh, Mahadevappa; Scatarige, John C.; Cooper, Joseph D.; Fishman, Elliot K.

doi:10.2214/ajr.177.6.1771273

Cited by 120 publications

(49 citation statements)

References 12 publications

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“…An automated exposure control system was switched on during all acquisitions (Care Dose 4D®; Siemens Medical Solutions) with a quality reference effective current-time product of 20 mAs. As defined by Mahesh et al, 14 effective tube current-time product corresponds to the tube current-time product divided by the pitch, whereby pitch is defined by Silverman et al 15 as the ratio between the table feed per rotation and the X-ray beam width. We used a dose modulation technique to reduce the radiation dose delivered to our volunteers and to abolish the effect of soft-tissue thickness of the chest wall in order to set lung attenuation measurements free of this thickness, including the influence of breasts (and their size) in females and not in males.…”

Section: Methods and Materials Subjectsmentioning

confidence: 99%

Effect of total lung capacity and gender on CT densitometry indexes

Walsdorff

Muylem

Gevenois

2016

BJR

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Objective: Testing the hypothesis that CT densitometry indexes could be influenced by total lung capacity (TLC), gender and height in normal individuals. Methods: In this ethics committee-approved prospective study, 100 healthy non-smoking volunteers who provided written informed consent were included. From a helical scan of the chest, the relative area (RA) of the lung with attenuation coefficients lower than 2960 HU and the 1st and 15th percentiles of the distribution of attenuation coefficients were calculated. Regression lines were drawn between each CT index and volunteers' height and total TLC at CT. Results: In males, there was no statistically significant correlation between any CT index and height. In females, there was a statistically significant correlation between the RA of the lung with attenuation coefficients lower than 2960 HU and the 1st percentile and height but not with the 15th percentile. For both genders, there were significant correlations between all CT indexes and TLC. The relationships between CT indexes and TLC were different in males and females. Conclusion: CT indexes are correlated with TLC and height but more closely with TLC than with height, and differently in males and females. Advances in knowledge: CT indexes are influenced by TLC, gender and height in normal individuals and are more closely correlated with TLC than with height. The relationships between CT indexes and TLC or height are different in males and females. CT indexes used to quantify emphysema should thus be adjusted according to TLC and gender.

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Section: Methods and Materials Subjectsmentioning

confidence: 99%

Effect of total lung capacity and gender on CT densitometry indexes

Walsdorff

Muylem

Gevenois

2016

BJR

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“…For each section position, the CT system calculates the average tube current, expressed as average effective mAs, throughout the duration of exposure. Effective mAs 18 are determined by dividing the product of milliamperes and rotation time by the pitch, which is the ratio between the table feed per rotation and the x-ray beam width or collimation. 19 The mean effective milliampere seconds of the whole examination are displayed at the scan console at the end of the examination and were recorded in our study.…”

Section: Ct Examinationsmentioning

confidence: 99%

Comparison of Low-Dose With Standard-Dose Multidetector CT in Cervical Spine Trauma

Mulkens¹,

Marchal²,

Daineffe³

et al. 2007

American Journal of Neuroradiology

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“…The CTDIw was estimated from the values of beam collimation, kilovolts and effective mAs. [12]. The measurements of weighted CT dose indices were performed within a plastic body phantom of 32 cm in diameter (referred to as the CT dose index body phantom [13] of an average-sized man), provided by the CT scanner manufacturer (Siemens).…”

Section: Radiation Dose Estimationmentioning

confidence: 99%

Low-dose multidetector-row CT angiography of the infra-renal aorta and lower extremity vessels: image quality and diagnostic accuracy in comparison with standard DSA

et al. 2005

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To investigate the possibility of reducing X-ray exposure during multidetector-row spiral computed tomographic (MDCT) angiography and to compare the image quality and diagnostic accuracy of different dosages with digital subtraction angiography (DSA) in the evaluation of the infra-renal aorta and lower extremities vessels. Seventy-five patients, randomly divided into three groups of 25 patients each, were evaluated for atherosclerotic disease with four-row spiral CT angiography (4x2.5 mm) and DSA. MDCT scanning parameters were kept constant, except for milliamperage (mAs): group A: 50 mAs; group B: 100 mAs; group C: 130 mAs. Images were analysed by two vascular radiologists in consensus. DSA represented the standard of reference. The diagnostic value of MDCT and total radiation exposure were evaluated for each data set. The simulated effective dose was 3.7 mSv for 50 mAs, 8.2 mSv for 100 mAs and 13.7 mSv for 130 mAs for men, and 4 mSv for 50 mAs, 8.9 mSv for 100 mAs and 14.8 mSv for 130 mAs for women. The dose reduction was 74% for group A and 40% for group B. The evaluation of the presence and degree of stenoses revealed a sensitivity, specificity, accuracy, PPV and NPV of 96%, 94%, 95%, 83% and 99% for Group A (50 mAs), 96%, 96%, 96%, 89% and 99% for Group B (100 mAs) and 98%, 96%, 97%, 91% and 100% for the standard dose protocol, Group C (130 mAs). Low-dose scanning is thus a feasible and accurate option for four-row CT angiography of the peripheral vessels. This technique provides substantial reduction of the radiation dose delivered to the patient while maintaining optimal diagnostic accuracy.

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Dose and Pitch Relationship for a Particular Multislice CT Scanner

Cited by 120 publications

References 12 publications

Effect of total lung capacity and gender on CT densitometry indexes

Effect of total lung capacity and gender on CT densitometry indexes

Comparison of Low-Dose With Standard-Dose Multidetector CT in Cervical Spine Trauma

Low-dose multidetector-row CT angiography of the infra-renal aorta and lower extremity vessels: image quality and diagnostic accuracy in comparison with standard DSA

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