Head MRI a ‘useful surrogate’ for abdominal CT in measuring body composition

MRI-based measurements of the head are sufficient to estimate body composition in the absence of CT measurements of abdominal fat, according to results of a new study published online in Clinical Radiology.

Recent research suggests that body composition plays a substantial role in cancer patients’ lives and impacts various aspects of their medical care, including quality of life, treatment response, treatment-related toxicity and survival.

That’s why developing new methods to better assess nutrition and body composition is of critical importance, according to lead author C.M. Lack, MD, and his colleagues at the Wake Forest School of Medicine in Winston-Salem, N.C.

“Increasing evidence suggests that weight, BMI, and body surface area are poor overall indicators of nutritional status, and that weight and BMI do not predict treatment-related toxicity,” the authors wrote. “Therefore more precise phenotypic measurements of body composition have been increasingly sought and used.”

Lack and his team set out to determine how well a MRI-based phenotypic body composition measure based on extracranial fat and muscle would compare with already established body type measurements using abdominal CT.

To do so, the researchers measured the body composition of 99 consecutive patients who had both a brain MRI and abdominal CT within a two-week span. Fat and muscle levels in the head were measured by both modalities.

Their results showed that when using either single-section or multi-section techniques, totals of MRI-based fat volumes in the head correlated with abdominal fat measurements obtained through CT, with no correlation found among muscle volumes in the head and abdomen.

“Based on the present results, head MRI-based measures may provide a useful surrogate for CT measurements of abdominal fat,” wrote the authors, “particularly in patients with neurological cancers, as head MRI (and not abdominal CT) is routinely and repeatedly obtained for the purpose of clinical care for these patients.”

While encouraged by their results, Lack and his team believe there is much work left to be done, suggesting that additional studies are needed to determine the best way to employ this method of body composition measurement for the benefit of cancer patients.

“One area of particular interest would be to evaluate the extent to which head MRI-based phenotypic measures of body composition predict treatment-related side effects, morbidity, and survival in patients with primary brain malignancy,” the researchers wrote. “To what degree these imaging phenotypes can be useful in predicting clinical outcomes, is a focus for future study.”