17 August 2026
Major scientific advances often start with seemingly simple questions, like the one asked by English electrical engineer Sir Godfrey Hounsfield and radiologist Jamie Ambrose: Is it possible to work out the contents of a box by taking multiple X-ray pictures in different positions around the object? Their solutions to the problem led to the development of Computed Tomography (CT). 20 years after Hounsfield received the Nobel Prize for medicine for his discovery, another simple question would ultimately lead to the development of perfusion CT: why do things enhance?
The answer lay within the discipline of physiology, and its depiction by nuclear medicine in particular and in 1991, a team from Cambridge, UK published in the Lancet the world’s first CT perfusion image acquired using a conventional CT scanner. Within the next 2 years, the team had extended the technique to allow for the dual blood supply of the liver, laying the foundations for its use in hepatic malignancy and diffuse liver disease. The following year, they presented the first case of CT perfusion imaging of the brain performed with iodinated contrast media at the 1994 Congress of the British Institute of Radiology.
With later developments, perfusion CT soon became a valuable clinical technique that could be used in nearly every radiology department. Advances in CT systems enabled multi-slice studies rather than the original single-slice approach, and the introduction of gated tomography allowed for imaging of myocardial perfusion. Optimised acquisition protocols ensured the quality of the contrast material bolus while minimising radiation dose. Commercial image processing software became available, offering corrections for respiratory motion and partial volume effects for small input vessels.
The main clinical application of perfusion CT lies in the management of stroke. The technique’s value has been recognised in clinical guidelines in many countries around the world and applied in the NHS for over 17 years. The ability to detect cerebral infarcts in the presence of a normal conventional CT and to delineate the extent of brain tissue at risk can guide interventional radiological management and other treatments for cerebrovascular accidents. In Australia, perfusion CT has been recognised as critical for the management of stroke in regional and rural settings.
Demonstrable links between CT perfusion measurements and the density of new blood vessels within tumours underpins the technique’s effectiveness in oncology, aiding the prediction and assessment of tumour response. Perfusion imaging can increase the utility of the CT component of PET-CT, generating multi-parametric biomarkers that provide unique information on tumour behaviour, including response to treatment. Emerging developments include incorporating perfusion CT into radiomics and augmenting the planning of tumour ablation methods.
A one-day conference to mark 35 years of perfusion CT and its current and future relevance to clinical radiology will be held on September 8th, 2026, at Downing College Cambridge. More information and registration for the meeting are available on the British Institute of Radiology website www.bir.org.uk
Major scientific advances often start with seemingly simple questions, like the one asked by English electrical engineer Sir Godfrey Hounsfield and radiologist Jamie Ambrose: Is it possible to work out the contents of a box by taking multiple X-ray pictures in different positions around the object? Their solutions to the problem led to the development of Computed Tomography (CT). 20 years after Hounsfield received the Nobel Prize for medicine for his discovery, another simple question would ultimately lead to the development of perfusion CT: why do things enhance?
The answer lay within the discipline of physiology, and its depiction by nuclear medicine in particular and in 1991, a team from Cambridge, UK published in the Lancet the world’s first CT perfusion image acquired using a conventional CT scanner. Within the next 2 years, the team had extended the technique to allow for the dual blood supply of the liver, laying the foundations for its use in hepatic malignancy and diffuse liver disease. The following year, they presented the first case of CT perfusion imaging of the brain performed with iodinated contrast media at the 1994 Congress of the British Institute of Radiology.
With later developments, perfusion CT soon became a valuable clinical technique that could be used in nearly every radiology department. Advances in CT systems enabled multi-slice studies rather than the original single-slice approach, and the introduction of gated tomography allowed for imaging of myocardial perfusion. Optimised acquisition protocols ensured the quality of the contrast material bolus while minimising radiation dose. Commercial image processing software became available, offering corrections for respiratory motion and partial volume effects for small input vessels.
The main clinical application of perfusion CT lies in the management of stroke. The technique’s value has been recognised in clinical guidelines in many countries around the world and applied in the NHS for over 17 years. The ability to detect cerebral infarcts in the presence of a normal conventional CT and to delineate the extent of brain tissue at risk can guide interventional radiological management and other treatments for cerebrovascular accidents. In Australia, perfusion CT has been recognised as critical for the management of stroke in regional and rural settings.
Demonstrable links between CT perfusion measurements and the density of new blood vessels within tumours underpins the technique’s effectiveness in oncology, aiding the prediction and assessment of tumour response. Perfusion imaging can increase the utility of the CT component of PET-CT, generating multi-parametric biomarkers that provide unique information on tumour behaviour, including response to treatment. Emerging developments include incorporating perfusion CT into radiomics and augmenting the planning of tumour ablation methods.
A one-day conference to mark 35 years of perfusion CT and its current and future relevance to clinical radiology will be held on September 8th, 2026, at Downing College Cambridge. More information and registration for the meeting are available on the British Institute of Radiology website www.bir.org.uk.
Photo: Perfusion CT pioneer Ken Miles (left) receiving from Sir Godfrey Hounsfield a certificate commemorating the 1999 Sir Godfrey Hounsfield Lectureship of the British Institute of Radiology.
