“…Multiple weight-based regimens using several size indices have shown more robust enhancement and comparable image quality to fixed-volume strategies, despite less use of materials and lower cost (31)(32)(33). However, no single weightbased method has been conclusively shown to be superior to the others, and the assessment of body size and body composition has proven challenging (34). In the present study, TBW was reported to be the most commonly used weight-based strategy.…”
Background Administration of contrast medium (CM) is an important image quality factor in computed tomography (CT) of the chest. There is no clear evidence or guidelines on CM strategies for chest CT, thus a consensus approach is needed. Purpose To survey the potential impact on differences in chest CT protocols, with emphasis on strategies for the administration of CM. Material and Methods A total of 170 respondents were included in this survey, which used two different approaches: (i) an online survey was sent to the members of the European Society of Thoracic Imaging (ESTI); and (ii) an email requesting a copy of their CT protocol was sent to all hospitals in Norway, and university hospitals in Sweden and Denmark. The survey focused on factors affecting CM protocols and enhancement in chest CT. Results The overall response rate was 24% (n = 170): 76% of the respondents used a CM concentration of ≥350 mgI/mL; 52% of the respondents used a fixed CM volume strategy. Fixed strategies for injection rate and delay were also the most common approach, practiced by 73% and 57% of the respondents, respectively. The fixed delay was in the range of 20–90 s. Of the respondents, 56% used flexible tube potential strategies (kV). Conclusion The chest CT protocols and CM administration strategies employed by the respondents vary widely, affecting the image quality. The results of this study underline the need for further research and consensus guidelines related to chest CT.
“…Multiple weight-based regimens using several size indices have shown more robust enhancement and comparable image quality to fixed-volume strategies, despite less use of materials and lower cost (31)(32)(33). However, no single weightbased method has been conclusively shown to be superior to the others, and the assessment of body size and body composition has proven challenging (34). In the present study, TBW was reported to be the most commonly used weight-based strategy.…”
Background Administration of contrast medium (CM) is an important image quality factor in computed tomography (CT) of the chest. There is no clear evidence or guidelines on CM strategies for chest CT, thus a consensus approach is needed. Purpose To survey the potential impact on differences in chest CT protocols, with emphasis on strategies for the administration of CM. Material and Methods A total of 170 respondents were included in this survey, which used two different approaches: (i) an online survey was sent to the members of the European Society of Thoracic Imaging (ESTI); and (ii) an email requesting a copy of their CT protocol was sent to all hospitals in Norway, and university hospitals in Sweden and Denmark. The survey focused on factors affecting CM protocols and enhancement in chest CT. Results The overall response rate was 24% (n = 170): 76% of the respondents used a CM concentration of ≥350 mgI/mL; 52% of the respondents used a fixed CM volume strategy. Fixed strategies for injection rate and delay were also the most common approach, practiced by 73% and 57% of the respondents, respectively. The fixed delay was in the range of 20–90 s. Of the respondents, 56% used flexible tube potential strategies (kV). Conclusion The chest CT protocols and CM administration strategies employed by the respondents vary widely, affecting the image quality. The results of this study underline the need for further research and consensus guidelines related to chest CT.
“…Participants were included in the overweight category if their BMI was ≥ 25 with a waist circumference ≥ 88 cm for females and ≥ 102 cm for males. The assessment was performed by a restricted number of specialized CT technologists/radiographers with experience and training to perform subjective assessment for the study [ 19 ]. Fig.…”
Background
Total body weight (TBW) is a frequently used contrast media (CM) strategy for dose calculation in enhanced CT, yet it is suboptimal as it lacks consideration of patient characteristics, such as body fat percentage (BFP) and muscle mass. Alternative CM dosage strategies are suggested by the literature. Our objectives were to analyze the CM dose impact when adjusting to body composition using methods of obtaining lean body mass (LBM) and body surface area (BSA) along with its correlation with demographic factors in contrast enhanced chest CT examinations.
Methods
Eighty-nine adult patients referred for CM thoracic CT were retrospectively included, categorized as either normal, muscular, or overweight. Patient body composition data was used to calculate the CM dose according to LBM or BSA. LBM was calculated with the James method, Boer method, and bioelectric impedance (BIA). BSA was calculated using the Mostellar formula. We then correlated the corresponding CM doses with demographic factors.
Results
BIA demonstrated the highest and lowest calculated CM dose in muscular and overweight groups respectively, compared to other strategies. For the normal group, the lowest calculated CM dose was achieved using TBW. The calculated CM dose was more closely correlated with BFP using the BIA method.
Conclusions
The BIA method is more adaptive to variations in patient body habitus especially in muscular and overweight patients and is most closely correlated to patient demographics. This study could support utilizing the BIA method for calculating LBM for a body-tailored CM dose protocol for enhanced chest CT examinations.
Relevance statement
The BIA-based method is adaptive to variations in body habitus especially in muscular and overweight patients and is closely correlated to patient demographics for contrast-enhanced chest CT.
Key points
• Calculations based on BIA showed the largest variation in CM dose.
• Lean body weight using BIA demonstrated the strongest correlation to patient demographics.
• Lean body weight BIA protocol may be considered for CM dosing in chest CT.
Graphical Abstract
Objective To compare a fixed-volume contrast medium (CM) protocol with a combined total body weight (TBW) and body composition-tailored protocol in chest CT. Methods and materials Patients referred for routine contrast enhanced chest CT were prospectively categorised as normal, muscular or overweight. Patients were accordingly randomised into two groups; Group 1 received a fixed CM protocol. Group 2 received CM volume according to a body composition-tailored protocol. Objective image quality comparisons between protocols and body compositions were performed. Differences between groups and correlation were analysed using t-test and Pearson’s r. Results A total of 179 patients were included: 87 in Group 1 (mean age, 51 ± 17 years); and 92 in Group 2 (mean age, 52 ± 17 years). Compared to Group 2, Group 1 showed lower vascular attenuation in muscular (mean 346 Hounsfield unit (HU) vs 396 HU; p = 0.004) and overweight categories (mean 342 HU vs 367 HU; p = 0.12), while normal category patients showed increased attenuation (385 vs 367; p = 0.61). In Group 1, strongest correlation was found between attenuation and TBW in muscular (r = −.49, p = 0.009) and waist circumference in overweight patients (r = −.50, p = 0.005). In Group 2, no significant correlations were found for the same body size parameters. In Group 1, 13% of the overweight patients was below 250 HU (p = 0.053). Conclusion A combined TBW and body composition-tailored CM protocol in chest CT resulted in more homogenous enhancement and fewer outliers compared to a fixed-volume protocol. Advances in knowledge This is, to our knowledge, the first study to investigate the impact of various body compositions on contrast medium enhancement in chest CT.
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