The United States District Court for the Southern District of New York provided another victory for the admissibility of diffusion tensor imaging.

Defendant moved in limine to preclude the trial testimony of four of the plaintiff’s expert witnesses. This included the testimony of neuroradiologist Gregory J. Lawler. Defendant argued that Dr. Lawler’s testimony should be excluded as not based upon a reliable methodology and that his testimony would not be relevant. Dr. Lawler interpreted an MRI in which he found a “focal T-2 white manner hyperintensity that appeared as a bright signal on the MRI scan and a corresponding decreased fractional anisotropy value.” Dr. Lawler concluded these findings “likely represented a focus of axonal injury/axonal loss after trauma.” Dr. Lawler proposed to testify that a T-2 hyperintensity and decreased fractional anisotropy values are evident from review of the MRI with DTI; that a T-2 hyperintensity is evident from his review of an earlier MRI post-incident and that the observed T-2 hyperintensity and decreased FA values likely represent a focus of axonal injury/axonal loss after a trauma.

Defendant’s objection to Dr. Lawler’s methodology was that plaintiff’s neurologist did not articulate “what is the normal” from which plaintiff’s FA values were deemed to have deviated. Defendant argued that Dr. Lawler did not specify whether the decreased FA values he identified in parts of plaintiff’s brain are low relative to other areas of plaintiff’s brain, typical FA values from corresponding areas of healthy brains, or some other baseline value. The court held those questions go to the weight of the evidence and could be pursued through vigorous cross-examination.

In opposing the motion, Dr. Lawler appended to his declaration an article by Hulkower, et al., “A Decade of DTI in Traumatic Brain Injury: Ten Years and 100 Articles Later” published in the American Journal of Neuroradiologists (2013).

Interestingly, the trial court did bar Dr. Lawler from testifying to the likelihood that plaintiff suffered a traumatic brain injury, relying on my book “Litigating Brain Injuries”, co-authored with Dr. Jeffrey A. Brown. The court, relying on my book, noted that the diagnosis of traumatic brain injury is a clinical diagnosis based on history, review of medical records, clinical examination and diagnostic testing. Since Dr. Lawler only interpreted the MRI with DTI, he could not make a diagnosis of traumatic brain injury.

The court also rejected defendant’s argument that Dr. Lawler’s testimony would not be helpful to a jury because he did not establish the cause of plaintiff’s brain injury. The court rejected this argument, finding “Dr. Lawler’s testimony will help the jury to understand the evidence and to use it to decide the factual questions in this case.” While the court barred Dr. Lawler from testifying as to the cause of plaintiff’s alleged brain injury and that the likelihood that his findings indicated traumatic brain injury, he could testify based on his general knowledge regarding the types of medical conditions and incidents that lead to T-2 hyperintensities, decreased FA values, or axonal injury or axonal loss.

The case citation is Tardif v. City of New York, 2022 WL 2195332 (U.S.D.C. SDNY 2022).