ProtocolPulse

General Principles & Governance

Imaging Protocols for CT and MRI · v2.1 · March 2026

Authorisation

All imaging requests must be justified by an IR(ME)R practitioner (radiologist or radiographer)

IR(ME)R 2017 (as amended 2024) Justification Requirement

Every CT must be individually justified under IR(ME)R 2017 (as amended 2024) — benefit must outweigh risk. Clinical indication and relevant clinical information must be documented on the request.

MRI Safety & Governance

MRI is governed by MHRA Safety Guidelines v4.3 (2021), not IR(ME)R. Each scanner requires a designated MR Responsible Person (MRRP) and access to an MR Safety Expert (MRSE).

Gadolinium-based contrast agents (GBCAs): All MRI contrast requires eGFR assessment. Macrocyclic agents preferred per MHRA guidance. Patients with eGFR <30 require senior radiology review. Risk of nephrogenic systemic fibrosis (NSF) with linear agents in renal impairment.

MRI in pregnancy: MRI may be used at any stage of pregnancy when clinically indicated (no ionising radiation). Gadolinium should be avoided unless the benefit clearly outweighs the risk — macrocyclic agents only, with senior radiology approval.

Implant safety: All patients must be screened for MRI-incompatible implants, devices, and foreign bodies prior to scanning. Refer to local MRI safety questionnaire and implant database.

Cross-Cutting Guidance

Governing Guidelines

ReferenceGuideline TitleYearLink
NICE NG232Head Injury(Replaces CG176)May 2023View ↗
NICE NG128Stroke and TIA(Replaces CG68)2019, updated 2022View ↗
NICE TA990Tenecteplase for Acute Ischaemic StrokeJuly 2024View ↗
NICE NG228Subarachnoid Haemorrhage2022View ↗
NICE NG41Spinal Injury2016View ↗
NICE NG234Spinal Metastases and MSCC(Replaces CG75)2023View ↗
NICE NG59Low Back Pain and Sciatica2016, updated 2020View ↗
NICE NG158Venous Thromboembolic Diseases including PE2020View ↗
NICE CG95Chest Pain of Recent Onset2010, updated November 2016View ↗
NICE NG122Lung Cancer2019, updated 2024View ↗
NICE CG163Idiopathic Pulmonary Fibrosis2013View ↗
NICE NG39Major Trauma2016View ↗
NICE NG208Heart Valve Disease2021View ↗
NICE NG156Abdominal Aortic Aneurysm2020View ↗
NICE CG147Lower Limb PAD2012, updated 2020View ↗
NICE NG147Diverticular Disease2019View ↗
NICE NG104Pancreatitis2018, updated 2020View ↗
NICE CG188Gallstone Disease2014View ↗
NICE NG85Pancreatic Cancer2018View ↗
NICE NG118Renal and Ureteric Stones2019View ↗
NICE NG151Colorectal Cancer2020View ↗
NICE CG122Ovarian Cancer2011View ↗
NICE NG131Prostate Cancer2019View ↗
NICE NG73Endometriosis2017, updated 2024View ↗
NICE NG236Cervical Cancer2023View ↗
NICE NG129Crohn's Disease2019View ↗
NICE NG12Suspected Cancer: Recognition and Referral2015, updated 2026View ↗
NICE NG101Early and Locally Advanced Breast Cancer2018View ↗
NICE CG164Familial Breast Cancer2013View ↗
NICE CG124Hip Fracture Management2011, updated 2023View ↗
NICE NG38Fractures (Non-complex)2016View ↗
NICE NG97Dementia2018View ↗
NICE NG217Epilepsies2022View ↗
NICE NG220Multiple Sclerosis2022View ↗
NICE NG99Brain Tumours (Primary) and Brain Metastases2018View ↗
NICE CG150Headaches in Over 12s2012View ↗
NICE NG98Hearing Loss in Adults2018View ↗
NICE NG36Cancer of the Upper Aerodigestive Tract2016View ↗
NICE NG145Thyroid Disease2019View ↗
NICE NG100Rheumatoid Arthritis2018View ↗
NICE CG102Bacterial Meningitis in Children2010, updated 2015View ↗
RCR iReferMaking the Best Use of Clinical Radiology, 8th edition2017, continuously updatedView ↗
RCR/RCEMAcute Aortic Syndrome Imaging PathwayJanuary 2024, revised March 2025
RCR BFCR(19)4Guidance on Gadolinium-based Contrast Agents2019
RCR CIBMRI Provision for Cauda Equina SyndromeFebruary 2023
RCR/RCOGIonising Radiation and Pregnancy2021
RCR/SCoR/RCPCHRadiological Investigation of Suspected Physical Abuse in Children2017, revised 2018
RCR/RCEMEmergency CT and IV Contrast(Joint Advisory Statement)Current
NHS TLHCTargeted Lung Health Check ProgrammeCurrent
NHS TDPTimed Diagnostic Pathway — Head and Neck Cancer2024
NHS AAA ScreeningAAA Screening ProgrammeCurrent
IR(ME)R 2017Ionising Radiation (Medical Exposure) Regulations 2017SI 2017/1322View ↗
IR(ME)R 2024 AmendmentIR(ME)R Amendment Regulations 2024SI 2024/896View ↗
MHRA MRI SafetySafety Guidelines for MRI Equipment in Clinical Use, v4.32021
BASSStandards of Care for Cauda Equina Syndrome2018
GIRFTNational Cauda Equina Syndrome Pathway2023
BSGGuidelines for Management of IBD in Adults2019
BAHNO/ENT-UKNational MDT Guidelines: Salivary Gland Tumours2016
BOA BOASTACL Injuries Management2020
ECCO/ESGARCross-sectional Imaging in IBDUpdated
ESCGuidelines on Cardiomyopathies2023
ESCGuidelines on Myocarditis2025
ESCGuidelines on Congenital Heart Disease in Adults2020
ESOCerebral Venous Thrombosis Diagnosis and Treatment2017
EASLClinical Practice Guidelines: Hepatocellular Carcinoma2018
RCPNational Clinical Guideline for Stroke, 5th edition2023
IAP-APAEvidence-based Guidelines for Acute Pancreatitis2013
WSESGuidelines for Acute Mesenteric Ischaemia2017
ATS/ERS/JRS/ALATIPF Evidence-based GuidelinesUpdated 2022

Applicability

These protocols are applicable to all clinical settings (ED, Inpatient, Outpatient). Age-specific criteria are noted where applicable.

Contrast Administration

No blood tests required for IV iodinated contrast authorisation in emergency CT — per joint RCEM/RCR advisory statement. eGFR thresholds apply for gadolinium-based MRI contrast agents.

Disclaimers

Not clinical advice. ProtocolPulse is a reference tool only. It does not constitute clinical advice and does not replace the professional judgement of a qualified clinician, radiographer, or radiologist. All imaging decisions remain the responsibility of the authorising IR(ME)R practitioner.

Guidelines may have been updated. All guidelines referenced are current at the stated version date (March 2026). Guidelines are subject to revision by NICE, RCR, and other issuing bodies at any time. Users must verify all criteria against the latest published source before relying on them clinically.

Use common sense. The criteria presented are summaries of source guidelines. They do not capture every clinical nuance. Users must apply professional judgement and common sense, and refer directly to the full cited guideline text if any content appears inconsistent with their clinical knowledge or local practice.

Individual patient factors. This tool does not account for individual patient contraindications, allergies, implant status, renal function, pregnancy, or any clinical circumstance not captured in the published guideline criteria.

IR(ME)R responsibility. ProtocolPulse does not fulfil, replace, or substitute for any employer obligation under IR(ME)R 2017, including the requirement to provide referral guidelines to referrers under Regulation 6(5)(a). It is a supplementary reference aid only.

Medical device status. ProtocolPulse has not been assessed or registered as a medical device under the UK Medical Devices Regulations 2002 or the MHRA's Software and AI as a Medical Device framework. Before deployment in a clinical NHS setting, the responsible organisation must conduct an MHRA classification assessment.

Created with the assistance of AI. The clinical content, protocol criteria, and guideline summaries in ProtocolPulse v2.1 were developed with the assistance of Claude (Anthropic). All clinical criteria have been cross-referenced against the cited source guidelines. AI-assisted content may contain errors or omissions — users should apply common sense and verify against the original cited sources.

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