Testicular torsion is a time critical condition for children and young people (CYP). It is difficult to diagnose without an operation. Missing it means the child will lose a testicle. There are no good diagnostic tests, only tests that delay the child's journey to theatre, which puts them at further risk of losing the testicle. Most boys with a painful testicle get a surgical exploration to see if it is torsion and to twist and fix it. Up to 85% of children having surgery will not have torsion. They will have something they didn't need surgery for. We want to see whether a new, low risk, fast investigation could be used to diagnose the problem, meaning no torsions are missed and less children have unnecessary surgery.

Children being taken to theatre for testicular pain for suspected torsion over a 1-year period will be registered prospectively. A clerking proforma will be utilised for all children with testicular pain with details including duration of pain, presentation pathway, address, dob, ethnicity, tanner stage, comorbidities and the standard questions in a clerking for children with testicular pain.

Children proceeding to theatre will be consented for injection of ICG within their consent for surgery by appropriately GCP trained and delegated study team members. . Age-appropriate information leaflets will be provided, and consent and assent taken as appropriate from potential participants and their guardians (if required). Children having consented will have allocation of a participant ID. They will then proceed for injection of indocyanine green after safe establishment of anaesthetic and with the surgical team present. After 5 minutes an image of the CYP scrotum will be taken prior to prepping. The images are taken using a specialist near infra-red (NIR) camera. This is a new imaging system for SCNFT, but technology used at Sheffield Teaching Hospitals and in other children's hospitals in the country. This NIR camera head requires a new stacker for theatres but is fully compatible with our systems. These images will be taken under the category ICG scrotum on the theatre tablets. These will be stored on a tablet and printed from the theatre stack and exported to the server as standard practice for all images in the surgical department. Participant ID will be attached to the images and the images will be stored in the electronic notes. Process in theatre in described in Appendix 3.

The findings at surgery will be recorded and describe torsion, degree of torsion, colour at surgery, bleed time. A second image will be taken in cases of torsion. Appendix 2, form 2 describes data collection taken in theatre. Once detorted a second image will be taken and processed similarly. Fixation will proceed as standard practice.

There will be no change in the patient pathway for acute scrotum. Any adverse events will be monitored via immediate reporting of side effects to PI Caroline MacDonald, see Appendix for theatre protocol.

All children with torsion will have a follow up phone call at 12 months to check testicular status and any adverse events. Those without torsion do not need long term follow up, as we do not expect late atrophy.

Early analysis of ICG findings with surgical findings will be undertaken. A study investigator (BMedSci Student from University of Sheffield), independent of the surgical or radiology team, blinded to surgical outcomes will assess the printed and electronic images and assess for dichotomous and graduated fluorescence findings. These then will be compared to surgical outcomes and diagnostic accuracy evaluated using standard diagnostic accuracy calculations. Outcomes will be compared by time to presentation, age and racial identification.

Inclusion Criteria:

• All children presenting with testicular pain, being taken to theatre for scrotal exploration at Sheffield Children's NHS Foundation Trust. Aged 0-19 years of age.

Exclusion Criteria:

• Children with any allergy to contrast medium or iodine will be excluded.
• Any family or young person > age 13 years refusing consent.
• Children without a GP will not be exempt from recruitment. No information is required from community care.

male only anatomy

All data will be anonymised. Dataset will be made available on mendeley database

Assessor of images blinded to surgical outcomes