Bariatric CT Imaging: Challenges and Solutions

Fursevich, Dzmitry; LiMarzi, Gary M.; O’Dell, M. Cody; Hernandez, Manuel A.; Sensakovic, William F.

doi:10.1148/rg.2016150198

Cited by 46 publications

(29 citation statements)

References 37 publications

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“…Obesity was noted to be a cause of non-diagnostic CTPA examinations in several studies, and the increasing prevalence of obesity may play a role in the worsening diagnostic yield of CTPA. 6 CTPA studies on overweight and obese patients show statistically significantly decreased levels of pulmonary artery enhancement, signal-tonoise ratio (SNR), contrast-to-noise (CNR) and subjective image quality 6,42 (Figure 2). In a retrospective study in 2016, Yeo et al found that 6% of 403 total CTPAs were indeterminate, with 23 suboptimal examinations, and 1 non-diagnostic examination.…”

Section: Challenges Of Imaging In Obesitymentioning

confidence: 99%

“…9,36,41 There is a statistically significant negative correlation reported between mean/peak vessel enhancement and patient size. 41,42 Lowering the kVp can increase HU in the pulmonary arteries, making them appear brighter, because the attenuation of the beam increases as the beam energy reaches the k-edge of iodine. Also, less contrast can be used, and radiation dose can be reduced compared to examinations using higher kVp.…”

Section: Challenges Of Imaging In Obesitymentioning

confidence: 99%

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Imaging of suspected pulmonary embolism and deep venous thrombosis in obese patients

Cascio

Hon

Haramati

et al. 2018

BJR

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Obesity is a growing problem around the world, and radiology departments frequently encounter difficulties related to large patient size. Diagnosis and management of suspected venous thromboembolism, in particular deep venous thrombosis (DVT) and pulmonary embolism (PE), are challenging even in some lean patients, and can become even more complicated in the setting of obesity. Many obstacles must be overcome to obtain imaging examinations in obese patients with suspected PE and/or DVT, and to ensure that these examinations are of sufficient quality to diagnose or exclude thromboembolic disease, or to establish an alternative diagnosis. Equipment limitations and technical issues both need to be acknowledged and addressed. Table weight limits and scanner sizes that readily accommodate obese and even morbidly obese patients are not in place at many clinical sites. There are also issues with image quality, which can be substantially compromised. We discuss current understanding of the effects of patient size on imaging in general and, more specifically, on the imaging modalities used for the diagnosis and treatment of DVT and PE. Emphasis will be placed on the technical parameters and protocol nuances, including contrast dosing, which are necessary to refine and optimize images for the diagnosis of DVT and PE in obese patients, while remaining cognizant of radiation exposure. More research is necessary to develop consistent high-level evidence regarding protocols to guide radiologists, and to help them effectively utilize emerging technology.

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Section: Challenges Of Imaging In Obesitymentioning

confidence: 99%

Section: Challenges Of Imaging In Obesitymentioning

confidence: 99%

Imaging of suspected pulmonary embolism and deep venous thrombosis in obese patients

Cascio

Hon

Haramati

et al. 2018

BJR

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“…Recent estimates suggest that obesity will affect more than 40% of the US population by 2030, and medical costs related to obesity in the United States were estimated at more than $140 billion in 2008 1,2 . Obesity presents problems for all medical imaging modalities but is especially problematic for computed tomography (CT), as the radiation exposure must be increased in obese patients to maintain diagnostic efficacy 3 . However, concerns about radiation dose may prevent radiologists from increasing exposure to the extent needed.…”

Section: Introductionmentioning

confidence: 99%

“…the radiation exposure must be increased in obese patients to maintain diagnostic efficacy. 3 However, concerns about radiation dose may prevent radiologists from increasing exposure to the extent needed.…”

mentioning

confidence: 99%

Effect of obesity on ability to lower exposure for detection of low‐attenuation liver lesions

Herts

Schreiner

Dong

et al. 2020

J Applied Clin Med Phys

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Purpose The purpose of this study was to assess the effect of obesity and iterative reconstruction on the ability to reduce exposure by studying the accuracy for detection of low‐contrast low‐attenuation (LCLA) liver lesions on computed tomography (CT) using a phantom model. Methods A phantom with four unique LCLA liver lesions (5‐ to 15‐mm spheres, –24 to –6 HU relative to 90‐HU background) was scanned without (“thin” phantom) and with (“obese” phantom) a 5‐cm thick fat‐attenuation ring at 150 mAs (thin phantom) and 450 mAs (obese phantom) standard exposures and at 33% and 67% exposure reductions. Images were reconstructed using standard filtered back projection (FBP) and with iterative reconstruction (Adaptive Model‐Based Iterative Reconstruction strength 3, ADMIRE). A noninferiority analysis of lesion detection was performed. Results Mean area under the curve (AUC) values for lesion detection were significantly higher for the thin phantom than for the obese phantom regardless of exposure level (P < 0.05) for both FBP and ADMIRE. At 33% exposure reduction, AUC was noninferior for both FBP and ADMIRE strength 3 (P < 0.0001). At 67% exposure reduction, AUC remained noninferior for the thin phantom (P < 0.0035), but was no longer noninferior for the obese phantom (P ≥ 0.7353). There were no statistically significant differences in AUC between FBP and ADMIRE at any exposure level for either phantom. Conclusions Accuracy for lesion detection was not only significantly lower in the obese phantom at all relative exposures, but detection accuracy decreased sooner while reducing the exposure in the obese phantom. There was no significant difference in lesion detection between FBP and ADMIRE at equivalent exposure levels for either phantom.

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“…With the prevalence of obesity ever increasing, we would encourage colleagues to consider this additional dimension when caring for the bariatric patient, and not just focus on body mass in isolation. Computed tomography scanners do vary in their gantry aperture, with more modern scanners typically 75–85 cm in diameter . This information should be available from radiology staff, or alternatively a simple tape measure may be enough to prevent a wasted journey to CT.…”

mentioning

confidence: 99%