Neuro-Oncology Imaging in Clinical Negligence Claims: Professor Sotirios Bisdas Shares His Medico-Legal Expertise

Ardent Expert Chambers Member Professor Sotirios Bisdas, Consultant Neuroradiologist, delivered a specialist webinar examining the role of neuro-oncology imaging in cases involving alleged delayed diagnosis, delayed referral, disputed tumour progression and the interpretation of complex radiological evidence.

Drawing on his extensive neuroradiology and medico-legal experience, Professor Bisdas explored how imaging can help reconstruct the evolution of a brain tumour, assess treatment response and inform questions around causation and prognosis.

The session also highlighted an equally important part of expert radiological work: understanding the limits of what imaging can reliably establish, particularly when retrospective opinions depend on scans taken months or years apart.

Reconstructing the Radiological Chronology

A central theme of Professor Bisdas’ webinar was the importance of chronology.

In neuro-oncology cases, the expert may need to review multiple scans taken at different stages of the patient’s clinical pathway and determine what was visible, when abnormalities first became apparent and how those findings evolved.

That process can involve comparing earlier imaging with later diagnostic scans and considering whether subtle abnormalities were genuinely identifiable at the time.

Professor Bisdas highlighted the importance of avoiding hindsight when conducting this type of review.

Once a tumour diagnosis is known, earlier imaging can appear more significant than it may reasonably have done when first reported. Expert assessment must therefore distinguish between what can be recognised retrospectively and what a competent radiologist should reasonably have identified prospectively.

Delayed Diagnosis and Referral

Cases involving alleged delayed diagnosis often require careful consideration of both the imaging findings and the clinical pathway surrounding them.

An abnormal scan does not exist in isolation. Its significance may depend on the symptoms that prompted imaging, the type of investigation performed, the information available to the reporting radiologist and what further investigation or referral followed.

Professor Bisdas explored how an expert may assess whether an abnormality warranted additional imaging, specialist neuroradiological review or referral to a neuro-oncology team.

The focus is not simply on whether a tumour was eventually present, but on whether the available imaging should reasonably have led to a different clinical response at an earlier point.

Understanding Tumour Progression

Brain tumours do not all behave in the same way.

Growth rate, radiological appearance and response to treatment can vary considerably according to tumour type and individual disease biology.

Professor Bisdas examined how serial imaging may help assess disease progression, while also highlighting the limitations involved in attempting to reconstruct precisely how a tumour developed between scans.

For an expert witness, this requires careful interpretation rather than assuming a simple linear pattern of growth.

The timing of radiological change must be considered alongside the known behaviour of the tumour and the wider clinical evidence before conclusions are reached about when disease was likely to have been detectable.

Imaging and Treatment Response

Imaging also plays a major role after diagnosis.

MRI and other investigations may be used to assess response to surgery, radiotherapy, systemic treatment or other neuro-oncological interventions.

Professor Bisdas explored the challenges involved in distinguishing true tumour progression from treatment-related change, an area where imaging appearances can sometimes overlap.

Post-treatment abnormalities may reflect residual disease, recurrent tumour, inflammation, treatment effect or other changes.

Expert interpretation therefore requires specialist understanding of both the imaging appearance and the treatment history.

This distinction can be particularly important where conclusions about prognosis or the effectiveness of earlier treatment depend on the interpretation of post-treatment scans.

Primary and Secondary Brain Tumours

Professor Bisdas also considered imaging across both primary brain tumours and secondary metastatic disease.

These conditions can differ considerably in their radiological characteristics, progression and treatment pathways.

An expert reviewing a neuro-oncology case may therefore need to consider not only whether an abnormality was present, but what type of disease process the imaging supported and how confidently that conclusion could be reached at the relevant time.

This specialist interpretation can become especially important where the imaging forms part of a larger question about diagnosis, staging or the likely clinical consequences of delay.

The Evidential Limits of Imaging

One of the strongest themes of Professor Bisdas’ session was that radiology can provide powerful evidence, but it does not provide certainty in every case.

Imaging quality, sequence selection, scan intervals and the inherent limitations of different modalities can all affect what can reasonably be concluded.

An apparently normal scan may not exclude every disease process, while a subtle abnormality does not necessarily mean that a definitive diagnosis could have been made at that point.

Professor Bisdas highlighted the importance of expert witnesses being clear about these boundaries.

A robust radiological opinion should explain not only what the imaging supports, but also where the evidence remains uncertain.

Avoiding Over-Interpretation

Retrospective review carries a particular risk of over-interpreting earlier imaging.

Once the eventual diagnosis and outcome are known, it can be tempting to construct a radiological narrative that appears more certain than the contemporary evidence justified.

Professor Bisdas’ approach emphasises the need to assess each scan on its own merits and within the information available at that stage.

Where an abnormality is subtle or equivocal, the expert should explain that uncertainty rather than forcing the imaging into a predetermined chronology.

This balanced approach is particularly important where competing expert opinions arise around the timing of diagnosis or tumour progression.

Imaging, Causation and Prognosis

Radiological evidence may also contribute to wider questions of causation and prognosis.

Where an earlier diagnosis is alleged to have been possible, the expert may be asked to consider what the imaging suggests about tumour burden or disease stage at that earlier point.

However, imaging alone may not determine whether earlier intervention would have altered the eventual outcome.

Professor Bisdas highlighted the importance of integrating radiological findings with oncological, surgical and other specialist evidence where appropriate.

This helps ensure that neuroradiological opinion remains focused on what the imaging can reliably establish while contributing meaningfully to the wider medico-legal analysis.

Specialist Expertise in Neuro-Oncology Imaging

As a Consultant Neuroradiologist, Professor Bisdas brings specialist expertise in the imaging of complex neurological disease, including primary and secondary brain tumours.

His webinar demonstrated how that expertise is applied when examining delayed diagnosis, scan interpretation, disease chronology, treatment response, tumour progression, causation and prognosis.

By combining detailed radiological analysis with a clear understanding of the limitations of imaging, Professor Bisdas provides an evidence-led approach to complex neuro-oncology cases where the interpretation of scans may become central to the medico-legal questions being considered.

Professor Sotirios Bisdas is a member of Ardent Expert Chambers. View his full member profile to learn more about his specialist expertise and medico-legal practice.

Watch Professor Sotirios Bisdas’ webinar, Neuro-Oncology Imaging in Clinical Negligence Claims >