PIUR tUS (3D tomographic ultrasound; PIUR imaging) generates 3D tomographic ultrasound images of the entire length of a blood vessel by extending regular 2D ultrasound scanners. This imaging can be used for abdominal aortic aneurysm (AAA) surveillance and endovascular aneurysm repair (EVAR) endoleak detection and classification. PIUR tUS can be used with any 2D ultrasound device and transducer. It turns the images collected into high-resolution tomographic 3D ultrasound images. The images are viewed and reported in a similar way to other 3D imaging techniques using multi-planar reconstructions and 3D volume, such as CT or MR angiography.
The company has also developed a smaller version of the device, PIUR tUS Infinity, which is designed to be more easily transported and cheaper (£450 per month). This version can currently only be used with linear transducers, but support will be added in 2020 so that it can be used for AAA surveillance.
The company states that other 3D or 4D technologies have a limited view, whereas PIUR tUS can produce images of the entire length of vessel if needed (for example, from diaphragm to groin).
AAAs may be found during screening (65-year-old men are invited for screening by the NHS AAA screening programme), when a person reports symptoms, or found during other scans (for example, CT or MRI). People with a family history of AAA may also be invited for screening. Ultrasound scanning screens for AAA, further treatment depends on the scan result:
If the aorta is less than 3 cm wide, there is no aneurysm. No further treatment or monitoring is needed.
If the aorta is 3 cm to 4.4 cm wide, there is a small aneurysm. The person will be invited back for scans every 12 months to monitor the growth of the aneurysm.
If the aorta is 4.5 cm to 5.4 cm wide, there is a medium aneurysm. The person will be invited back for scans every 3 months to monitor the growth of the aneurysm.
If the aorta is 5.5 cm or wider, there is a large aneurysm. The person will be referred to a specialist for treatment.
An endoleak is a common complication of the EVAR procedure. During EVAR, a fabric-covered stent is put in place to reinforce the areas of the aorta that are weak because of an aneurysm. The stent provides a new path for blood flow, which keeps blood from reaching the aneurysm. An endoleak is a complication that affects about 15% to 25% of patients who have EVAR. It means that some blood flow stays in the aneurysm cavity. Endoleaks are classified by type I to V:
Type I: blood leaks around the top or the bottom of the stent. Because the blood has high flow, type I endoleaks are treated urgently.
Type II: blood leaks into the aneurysm from small branches of the aorta. This is the most common type of endoleak. Type II endoleaks can sometimes stop without treatment but will need to be checked regularly.
Type III: blood leaks through separations in the overlapping stent graft components into the aneurysm cavity.
Type IV: blood leaks through the pores of the stent graft, this is rare in new stent technologies.
Type V: these types of endoleaks are not well understood and usually result in an endograft reinforcement procedure or open surgery.
An endoleak usually has no symptoms and is often detected during routine follow-up visits (with vascular surgeons, vascular scientists or a nurse). Duplex ultrasound or CT imaging is used to examine the site of the EVAR.
The following guidance has been identified as relevant to this care pathway:
NICE's in development guideline on abdominal aortic aneurysm: diagnosis and management. The draft guideline states that if contrast-enhanced CT angiography is contraindicated, contrast-enhanced ultrasound should be considered for endoleak detection. The committee did not recommend colour duplex ultrasound because of variable diagnostic accuracy. The draft guideline states that further evidence is needed on surveillance after EVAR.
PIUR tUS could be used to diagnose AAA, for AAA surveillance and after EVAR.
PIUR tUS users should be competent in colour duplex and contrast-enhanced ultrasound and should attend a half-day training course on using the technology. This is included in the cost of the technology and provided by the company. After training, the company recommends that the first 20 uses are done under the supervision of a competent user or compared with a gold standard (for example, CT scan).
PIUR tUS would be used in outpatient tertiary referral centres by competent users such as vascular surgeons and scientists, screening technicians, sonographers and radiologists.
The company states that if the technology is used for endoleak detection in 100 people per year for 5 years (used 5 days a week) PIUR tUS would cost around £225.60 per patient.
Training is needed to use the technology, the company states that this will take 1 day to 2 days. Training is provided by the company at no additional cost. The company recommends that a clinician's first 20 uses of the technology should be done under supervision of a competent user or compared with a CT scan. These costs have not been included in the calculations.
Cost of technology, £43,000. The technology can be used for 5 years and must be serviced once a year by a qualified technician. These costs were provided by the company.
Ultrasound contrast medium (for EVAR only), £54 per patient. Cost provided by the company.
Plaster, £0.02, 1 plaster needed to cover the site of cannula insertion.
Alcohol wipes, £0.02. The company states that 2 wipes will be used to clean the sensors for each patient.
The Payment by Results tariff reimbursement for AAA screening and surveillance using duplex ultrasound is £49 per scan, in an outpatient setting.
For EVAR surveillance, the company estimates that contrast-enhanced ultrasound costs £105 (includes cost of contrast medium) and will need a sonographer. A CT angiogram costs £285 and will need a radiologist whose time will cost around £20 per appointment.
PIUR tUS is currently used in 5 university hospitals and in 2 private healthcare centres in the UK.
The device would be an additional cost to standard care because a sonographer and ultrasound machine are needed. Adoption of PIUR tUS might reduce resource consequences overall because of a reduced need for CT scans and surgical intervention.
PIUR tUS can work with existing ultrasound systems.