EXP v Barker

A reasonably competent neuroradiologist must investigate imaging that gives sufficient reason to suspect an aneurysm, even where the scan was ordered for another purpose and has recognised limitations. In assessing finely balanced expert evidence, the court may give substantial weight to concerns about an expert’s independence and objectivity. An expert’s relevant connection with a party or witness should be disclosed fully and at an early stage. Such a connection does not automatically make the evidence inadmissible. The court must assess the nature and extent of the connection, the expert’s expertise and ability to perform the primary duty to the court, and the available alternatives. Here, the claimant established that the 1999 MRI showed an aneurysm which later ruptured, and that a competent neuroradiologist would have reported it.

The claimant, a District Judge, alleged that the defendant consultant radiologist negligently failed to identify and report a right middle cerebral artery aneurysm on an MRI scan performed in April 1999. The aneurysm ruptured in 2011, causing catastrophic neurological injury. By trial, causation was no longer pursued as a contested issue. The central question was whether the 1999 images showed an aneurysm which a reasonably competent neuroradiologist should have identified and reported.

The claimant relied principally on Dr Butler, supported by neurosurgical evidence from Mr Kirkpatrick. The defendant relied principally on Dr Molyneux, whose previous professional relationship with the defendant had not been fully disclosed before trial.

1. Admissibility and independence of expert evidence. The court adopted the principles summarised in Phipson on Evidence. An expert’s interest or connection does not automatically make evidence inadmissible. The court must consider the nature and extent of the connection, the expert’s relevant expertise, and whether the expert understands and can perform the primary duty to the court. The issue is one of fact and degree. Early disclosure is important, and any remaining concern may affect the weight of the evidence even where it does not justify exclusion.
2. The defendant and Dr Molyneux had failed substantially to disclose the lengthy and close mentoring, professional and collegial relationship between Dr Molyneux and the defendant. The court admitted Dr Molyneux’s evidence because of his expertise and the consequences of exclusion, but gave it substantially reduced weight. His failure to challenge seriously deficient material relied upon by the defence reinforced the concern about his objectivity.
3. Liability. The MRI was not intended to detect an aneurysm and was a relatively crude instrument for that purpose. Nevertheless, the possible consequences of leaving an aneurysm undetected required close scrutiny. The court preferred Dr Butler’s evidence that the images contained sufficient features of abnormality to trouble a competent neuroradiologist and require further investigation. Mr Kirkpatrick’s supporting evidence was also given weight.
4. On the balance of probabilities, the aneurysm visible on the 1999 images was the same aneurysm that ruptured in 2011. The differences in apparent orientation did not outweigh the close anatomical relationship, the limitations of the earlier scan, and Mr Kirkpatrick’s explanation that the vessel might have rotated following the later haemorrhage.
5. The court therefore found that a competent practitioner would have concluded that the 1999 MRI showed an aneurysm and should have reported it. Liability was determined in favour of the claimant. No question of causation required decision.