Imaging Techniques

In order to properly assess the risk of type 2 diabetes and cardiovascular disease (CVD), it is vital to consider regional body fat distribution in addition to overall obesity. Epidemiological studies have clearly shown that abdominal obesity is the form of overweight/obesity associated with the highest risk of complications. However, most epidemiological studies have evaluated body fat distribution using simple and inexpensive anthropometric tools such as waist circumference. The development of imaging techniques such as computed tomography and magnetic resonance imaging has enabled visceral and subcutaneous fat to be measured with a high degree of accuracy. Using these techniques, researchers have been able to determine—for any given amount of total body fat—that individuals with a selective excess of visceral fat are significantly more likely to develop cardiovascular or diabetic complications than subjects with excess subcutaneous fat. More importantly, the amount of visceral fat has been shown to predict the risk of type 2 diabetes and total mortality. Imaging techniques have therefore enhanced our understanding of the importance of visceral fat to the clustering abnormalities of the metabolic syndrome.

Key Points

• CT is a criterion method for assessing visceral fat.
• CT can also be used to measure ectopic fat in the liver and skeletal muscle.
• High cost and radiation exposure currently limit the routine use of this tool for assessing body composition and related health risk in clinical practice.

Read more on Computed Tomography (CT).

Key Points

• MRI is a criterion method for assessing visceral fat.
• MRI can be used to measure ectopic fat deposition in the liver and skeletal muscle.
• High cost and limited availability currently hinder the routine use of this tool for assessing body composition and related health risk in clinical practice.

Read more on Magnetic Resonance Imaging (MRI).

Key Points

• DEXA is a useful tool for assessing total adiposity but is limited in its ability to assess visceral fat.
• Ultrasonography may be a useful tool for assessing visceral fat in clinical practice.
• As measured via ultrasonography, visceral fat thickness is a correlate of cardiometabolic risk factors.

Read more on Other Imaging Techniques.