Hypercarbic Challenge May Show Abnormal Brain Physiology in Concussed Athletes

Increased cerebrovascular reactivity (CVR) in college athletes following a sports-related concussion may be related to recurring headache symptoms and could be an indicator of acute injury, according to presenter Adam R. Militana, M.D., Monday at RSNA 2014.

By Paul LaTour

Adam R. Militana, M.D.

"I don't want to overstate any of our findings, but they do hint at an underlying physiology there," said Dr. Militana, a third-year resident at Vanderbilt University School of Medicine.

Researchers studied seven college athletes (four men, three women, from ages 18-22) in three to six days following sports-related concussions, which were diagnosed by a sports medicine physician. They had no history of prior concussion and only one noted a prior migraine condition.

Using functional MRI with a hypercarbia challenge, the researchers found CVR increased approximately 33 percent across all regions of interest (ROI) in subjects compared with the control patients. The increase is associated with more recent injury, and in one region it is also associated with increased headache symptoms.

"Some regions were more elevated than others, but they increased much more than the controls," Dr. Militana said. "This is unusual in CVR work."

He added that imaging has played a limited role in assessment and treatment of concussions. The findings of the pilot study indicate that increased CVR may be an objective measure that could lead to an increased role for imaging in the future in assessing concussions, especially when it relates to return-to-play symptoms for concussed athletes.

"We hope this measure will help inform clinical decision-making in the future, in particular, return-to-play decisions," Dr. Militana said.

No Correlation Between Innings Pitched and Degenerative Changes for Pitchers

Nicholas M. Gutierrez, M.D.

In a separate study of Major League Baseball (MLB) pitchers, researchers found no statistical significant correlation between the number of innings pitched and any one characteristic MRI finding encountered in the throwing elbow, according to a study presented Monday.

"The professional pitcher's elbow is subjected to a rather uniform and repetitive valgus torque that can lead to a characteristic spectrum of adaptive and degenerative changes that are readily identified on MRI," said lead author Nicholas M. Gutierrez, M.D., a resident at the University of Miami Jackson Memorial Hospital. "However, these findings do not necessarily correlate with current or future development of elbow pain or dysfunction."

Dr. Gutierrez and colleagues examined 26 asymptomatic MLB pitchers (asymptomatic being defined as no related stays on the disabled list in the two seasons prior to the MRI and no elbow complaints at the time of the MRI).

While the researchers found a trend that pointed to a correlation between innings pitched and increased pathological findings (those related to valgus extension overload), their hypothesis failed to reach statistical significance.

The researchers also said the pathologic changes in their elbows do not predict future placement, or stay, on the disabled list.

"It is important to avoid erroneous conclusions based on MRI findings in asymptomatic baseball pitchers," Gutierrez cautioned. "These pathologic findings should not lead to unnecessary treatment impacting a player's career and marketability."

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