SAP scan explained

A SAP scan is a type of nuclear medicine imaging test which uses iodine-123 (¹²³I) and serum amyloid P component (SAP) to diagnose amyloidosis.^{[1] [2]}

In patients with amyloidosis, large deposits of SAP coat the affected organs, in addition to the low levels normally found in the blood stream.^[3] The injected ¹²³I-SAP localises specifically to amyloid deposits, showing up as hot spots in the image.^[4]

Procedure

The radiopharmaceutical is injected into the patient, with imaging taking place on a gamma camera 6-24 hours later. An early blood-pool image provides a baseline for comparison with the organ SAP uptake after 24 hours.

Availability

Europe

¹²³I-SAP was granted orphan designation by the European Medicines Agency in 2003, however this was withdrawn in 2016.^[5]

SAP scanning is only carried out at two European centres; in the United Kingdom from the National Amyloidosis Centre, based at the Royal Free Hospital,^[6] and in the Netherlands at University Medical Center Groningen.^[7]

North America

SAP scanning is not approved in the United States due to its use of human blood products.

See also

• DPD scan

Notes and References

1. Lass . Piotr . Nuclear imaging of amyloidosis . Polish Journal of Radiology . 2014 . 79 . 222–227 . 10.12659/PJR.890147 . 4111651.
2. Sachchithanantham . S. . Wechalekar . A. D. . Imaging in systemic amyloidosis . British Medical Bulletin . 29 July 2013 . 107 . 1 . 41–56 . 10.1093/bmb/ldt021 . 23896486 . free.
3. Web site: The SAP scan (AL amyloidosis) . Myeloma UK . 28 July 2019 . en.
4. Sachchithanantham . S. . Wechalekar . A. D. . Imaging in systemic amyloidosis . British Medical Bulletin . 29 July 2013 . 107 . 1 . 41–56 . 10.1093/bmb/ldt021 . 23896486. free.
5. Web site: EU/3/03/134 - Iodine (123I) Serum Amyloid P . European Medicines Agency . 28 June 2019 . en . 17 September 2018.
6. Web site: NHS STANDARD CONTRACT FOR DIAGNOSTIC SERVICE FOR AMYLOIDOSIS . NHS England . 28 June 2019 . 2013.
7. Noordzij . Walter . Glaudemans . Andor W. J. M. . Slart . Riemer H. J. A. . Dierckx . Rudi A. . Hazenberg . Bouke P. C. . Clinical use of differential nuclear medicine modalities in patients with ATTR amyloidosis . Amyloid . 22 August 2012 . 19 . 4 . 208–211 . 10.3109/13506129.2012.717993 . 17504868 .