🫁Chest X-Ray (CXR) — Systematic Interpretation
Always use a systematic approach: RIPE (Rotation · Inspiration · Projection · Exposure) then zones → structures → periphery.
Technical Quality Check
- Rotation: Medial clavicle ends equidistant from spinous process
- Inspiration: 6 anterior ribs / 10 posterior ribs visible
- Projection: PA (posteroanterior) = gold standard; AP magnifies heart
- Exposure: Vertebrae visible through cardiac shadow
Cardiac
- Cardiomegaly: Cardiothoracic ratio >0.5 on PA film
- Hilar enlargement: Lymphadenopathy, pulmonary hypertension, sarcoid
- Mediastinal widening: >8 cm — aortic dissection until proven otherwise
Lung Zones — Key Patterns
| Pattern | Appearance | Causes |
|---|
| Consolidation | Opacification + air bronchogram | Pneumonia, haemorrhage, tumour |
| Collapse | Volume loss, displaced fissure | Mucus plug, tumour, foreign body |
| Effusion | Blunted costophrenic angle, meniscus | Heart failure, infection, malignancy |
| Pneumothorax | Visible pleural edge, absent lung markings | Spontaneous, trauma, iatrogenic |
🦴Abdominal X-Ray (AXR) — Systematic Interpretation
Bowel Gas Pattern
- Small bowel: central, <3 cm, valvulae conniventes (complete folds)
- Large bowel: peripheral, >3 cm, haustra (incomplete folds)
- Obstruction SBO: Dilated small bowel loops, step-ladder pattern
- Obstruction LBO: Dilated large bowel proximal to obstruction
- Volvulus: Coffee bean / kidney sign (sigmoid)
- Free gas: Subdiaphragmatic air — perforation until proven otherwise
Vertebrae & Psoas
- Scoliosis, vertebral fractures, loss of disc height
- Loss of psoas shadow: retroperitoneal collection/haematoma
Calcifications on AXR
- Renal stones: Radio-opaque (calcium oxalate) — 90% visible
- Gallstones: Only 10-15% visible (pure cholesterol = lucent)
- AAA calcification: Aortic wall calcification — size assessment needs USS/CT
- Bladder stones: Pelvic calcification
- Pancreatic calcification: Chronic pancreatitis
Foreign Bodies
- Surgical clips, ingested items, IUDs, bullets
- Always check for retained surgical items post-op
⚠️Radiation Safety — ALARA Principle
ALARA: As Low As Reasonably Achievable — minimise radiation exposure while maintaining diagnostic quality.
ALARA in Practice
- Justify every exposure — clinical indication documented
- Minimise repeat exposures (positioning, technique)
- Distance: inverse square law — double distance = quarter dose
- Shielding: lead aprons (0.25 mm Pb), thyroid collars, gonadal shields
- Collimation: restrict beam to area of interest
Lead Shielding — Nursing Role
- Ensure shielding available for reproductive organs in patients of childbearing age
- Staff wear lead aprons if required to remain in room
- Lead aprons inspected regularly — do NOT fold (cracks lead)
- Dosimetry badges worn outside apron at collar level
- Pregnant staff: additional dosimetry badge at waist
Pregnancy & Ionising Radiation
- Always ask: "Could you be pregnant?" before imaging
- Fetus most vulnerable: first trimester (organogenesis 3-8 weeks)
- Defer non-urgent CXR / X-ray if pregnant (especially <12 weeks)
- If urgent CXR required: minimal risk — fetal dose extremely low (0.001 mSv)
- Abdominal/pelvic X-ray in pregnancy: risk-benefit discussion, document consent
- CT abdomen/pelvis in pregnancy: significant fetal dose — radiology consult essential
🔊Ultrasound (USS)
USS Principles & Advantages
- No ionising radiation — safe in pregnancy, children, repeated use
- Real-time imaging — dynamic assessment
- Portable — bedside, ICU, ED use
- Cost-effective, no contrast required (usually)
- Limitations: Operator-dependent, bowel gas limits views, poor for bone/lung
Common Indications
- Hepatobiliary: gallstones, cholecystitis, liver lesions, CBD dilation
- Renal: hydronephrosis, renal stones, masses
- Obstetric: fetal assessment, dating, placenta
- Vascular: DVT (compression USS), carotid doppler, AAA screening
- Pelvic: uterus, ovaries, IUCD position
- Thyroid & neck: nodules, lymphadenopathy
USS-Guided Procedures — Nursing Role
Aseptic non-touch technique (ANTT) is mandatory for all USS-guided invasive procedures.
- USS-guided drainage: Pleural/ascitic/abscess — prepare sterile field, specimen containers, monitor vital signs
- USS-guided biopsy: Liver/renal/thyroid/lymph node — consent confirmed, coagulation checked (INR/platelets), post-procedure observation 1-4h
- USS-guided line insertion: Central venous catheter, PICC — sterile gown/gloves, confirm tip position on CXR post-insertion
- Thoracocentesis: Patient upright/leaning forward, mark site, confirm residual fluid post-procedure
- Paracentesis: Pre-albumin (if cirrhotic — give IV albumin 8g/L drained), monitor post-procedure
🚑FAST Scan — Focused Assessment with Sonography in Trauma
FAST Scan Views (4 windows)
- Right upper quadrant (RUQ): Morison's pouch — hepatorenal space
- Left upper quadrant (LUQ): Splenorenal space (perisplenic)
- Pelvic: Pouch of Douglas / rectovesical pouch (suprapubic)
- Pericardial: Subxiphoid / parasternal — pericardial effusion/tamponade
- Extended eFAST: Adds bilateral lung views — haemothorax, pneumothorax
FAST Interpretation & Nursing Actions
- Free fluid (anechoic/black stripe) in peritoneum = haemoperitoneum until proven otherwise
- Pericardial effusion with haemodynamic instability = tamponade — prepare for pericardiocentesis
- Positive FAST in trauma → activate massive transfusion protocol if unstable
- FAST can miss retroperitoneal blood — CT still required if stable
- Serial FAST scans may be performed — document findings with time
- Nursing: ensure large bore IV access, bloods (FBC/coag/G&S), keep patient warm
🔬CT Principles — Hounsfield Units (HU)
CT measures X-ray attenuation as Hounsfield Units (HU). Water = 0 HU by definition. Higher density = brighter (white); lower density = darker (black).
| Tissue | HU Range | Appearance | Clinical Example |
|---|
| Air | –1000 | Black | Lung, bowel gas, pneumothorax |
| Fat | –100 to –50 | Dark grey | Subcutaneous fat, retroperitoneal fat |
| Water / CSF | 0 | Grey | Simple cyst, CSF |
| Soft tissue / muscle | 20–80 | Mid grey | Solid organs, muscle |
| Acute blood | 50–70 | Bright grey | Acute haematoma, subarachnoid haemorrhage |
| Calcification / bone | >400 | White | Cortical bone, calcified plaque |
| Contrast-enhanced | 100–300+ | Bright white | Vessels, enhancing tumour |
💻CT Indications by Body Region
CT Chest
- PE: CTPA (CT pulmonary angiogram) — gold standard; Wells score/D-dimer first
- Pneumonia: Extent, complications (empyema, abscess)
- Aortic pathology: Dissection, aneurysm — IV contrast essential
- Lung cancer: Staging, nodule characterisation
- Mediastinal mass: Lymphoma, thymoma
- Pleural disease: Mesothelioma, complex effusion
- HRCT: Interstitial lung disease (no contrast)
CT Abdomen & Pelvis
- Surgical abdomen: Appendicitis, diverticulitis, bowel obstruction, perforation
- Trauma: Liver/spleen laceration, mesenteric injury — FAST positive or unstable
- Cancer staging: Colorectal, ovarian, renal, bladder
- Renal colic: Non-contrast KUB CT (stones)
- AAA: Size, anatomy pre-EVAR
- Liver: Characterise lesions (arterial + portal + delayed phase)
CT Head / Spine
- Non-contrast CT head: Acute stroke (haemorrhage vs ischaemia), head injury, LP exclusion (raised ICP)
- CT angiography: Intracranial aneurysm, AVM, carotid stenosis
- CT spine: Trauma — C-spine clearance, fractures, cord compression
- CT perfusion: Stroke — penumbra assessment in thrombectomy candidates
💉Contrast-Enhanced CT — Phases
IV Contrast Phases
| Phase | Timing Post-Injection | Use |
|---|
| Non-contrast | — | Haematoma, stones, baseline |
| Arterial | ~25–35 sec | Vascular anatomy, HCC, aortic dissection |
| Portal venous | ~60–70 sec | Liver parenchyma, bowel, most abdominal pathology |
| Delayed | 3–5 min | Urothelial cancer, characterise lesions, renal collecting system |
IV Contrast — Nursing Preparation
- IV access: Minimum 18G cannula (20G minimum for standard; 18G for CTPA/CT aorta)
- Site: Antecubital fossa preferred (high flow rates 3–5 mL/s)
- Patency check: Flush with 20 mL saline — check no swelling/pain
- Pre-hydration: IV 0.9% NaCl 500 mL–1L for high-risk renal patients before and after
- eGFR check: Recent result required (within 3 months; within 6 weeks if diabetic/CKD)
- Allergy history: Document prior contrast reactions
- Metformin: Hold if eGFR <60 — see Tab 5
- Thyroid function: Contrast may affect thyroid — notify endocrinology if hyperthyroid on treatment
🚨Contrast Reactions — Classification & Management
Mild Reaction
Features: Nausea, vomiting, urticaria (hives), pruritus (itching), flushing, mild anxiety
Management:
— Reassure patient
— Monitor vital signs
— Oral/IV antihistamine (cetirizine or chlorphenamine)
— Usually self-limiting within 30–60 min
— Observe for progression
Moderate Reaction
Features: Bronchospasm, laryngospasm, tachycardia/bradycardia, hypertension/hypotension, facial oedema
Management:
— Call for help / alert team
— IM Adrenaline 0.5 mg (1:1000) if bronchospasm / laryngospasm
— Nebulised salbutamol (bronchospasm)
— IV access — IV fluids
— Monitor SpO2, ECG
Severe / Anaphylactoid
Features: Cardiovascular collapse, severe bronchospasm, stridor, loss of consciousness, cardiac arrest
Management: TREAT AS ANAPHYLAXIS
— Call resuscitation team
— IM Adrenaline 0.5 mg (1:1000) IMMEDIATELY
— Repeat every 5 min if needed
— IV fluid bolus (500 mL 0.9% NaCl)
— Airway management / supplemental O2
— IV hydrocortisone 200 mg
— IV chlorphenamine 10 mg
Documentation: Record contrast agent name, batch number, volume injected, reaction onset time, treatment given, and patient outcome in all contrast reaction incidents. Complete incident report.
🫘eGFR & Renal Protection with Contrast
| eGFR (mL/min/1.73m²) | Risk Level | Action |
|---|
| >60 | Low Risk | Standard iodinated contrast — no special precautions beyond hydration |
| 45–60 | Caution | IV hydration, ensure well-hydrated, inform radiologist |
| 30–45 | Moderate Risk | IV pre/post-hydration 0.9% NaCl, iso-osmolar contrast (iodixanol), radiologist discussion, hold metformin |
| <30 | High Risk | Risk-benefit analysis, radiologist + nephrologist discussion, use iso-osmolar contrast, aggressive hydration, consider alternative imaging (MRI/USS) |
| Dialysis-dependent | Special | Contrast can be used — dialysis timing does NOT need to be adjusted urgently (contrast removed by dialysis) |
Contrast-Induced AKI (CI-AKI): Risk overestimated historically. True CI-AKI is rare with modern iso-osmolar agents and adequate hydration. However precautions are essential in CKD, diabetes, myeloma, and dehydration.
🧲MRI Principles
MRI uses strong static magnetic field + radiofrequency (RF) pulses + gradient fields. No ionising radiation. Excellent soft tissue contrast.
How MRI Works (simplified)
- Strong magnetic field (1.5T or 3T) aligns hydrogen protons in the body
- RF pulses disturb alignment; protons release energy as they realign
- Different tissues relax at different rates (T1 and T2 relaxation times)
- T1: Fat = bright, fluid = dark (anatomy)
- T2: Fluid = bright (pathology — oedema, tumour, effusion)
- DWI: Diffusion-weighted imaging — acute stroke, abscess, tumour
MRI Indications
- Brain: Stroke (DWI), tumour, MS, encephalitis, posterior fossa pathology
- Spine: Disc herniation, cord compression, myelitis
- MSK: Ligament/tendon injuries, cartilage, bone marrow oedema
- Pelvis: Prostate, endometrial, cervical, rectal cancer staging
- Liver: Lesion characterisation (hepatobiliary agents)
- Cardiac MRI: Cardiomyopathy, myocarditis, viability
- MRCP: Biliary/pancreatic ducts (no contrast)
🚫MRI Absolute Contraindications
STOP — do NOT send patient to MRI without completing full safety screening. Ferromagnetic implants in a strong magnetic field can cause serious injury or death.
Absolute Contraindications
- Cochlear implants (unless verified MRI-conditional)
- Pacemaker or ICD — unless MRI-conditional verified with vendor/cardiology protocol
- Ferromagnetic aneurysm clips (non-titanium)
- Metallic intraocular foreign body (welding history — X-ray orbits first)
- Spinal cord stimulator (unless MRI-conditional)
- Some vascular stents (early post-implant <6 weeks — check vendor)
Relative Contraindications
- First trimester pregnancy (relative — avoid unless urgent; MRI preferred over CT in pregnancy if needed)
- Claustrophobia (sedation/GA may be required)
- Severe renal impairment for gadolinium (see below)
MRI-Conditional Devices
MRI-conditional = safe under specific conditions (field strength, orientation, SAR limits). NEVER assume safe without checking.
- MRI-conditional pacemakers: Require specific programming before scan, monitoring during scan, reprogramming after — cardiology involvement mandatory
- Neurostimulators: Vendor protocol, field strength specific
- Orthopaedic metalwork: Most titanium implants safe — check with MRI department; causes image artefact but usually not dangerous
- Stents & filters: Most safe after 6 weeks, check manufacturer data
- Prosthetic heart valves: Most modern valves are MRI-compatible
- Reference: MRISafety.com and device documentation
📋Pre-MRI Safety Screening — Nursing Role
The nurse is the last safety checkpoint before the patient enters the MRI suite. This is a critical patient safety responsibility.
MRI Safety Screening Form — Key Items
- Cardiac pacemaker / ICD / cardiac device (device card requested)
- Cochlear implant / hearing device
- Neurostimulator / deep brain stimulator
- Insulin pump (must be removed — not MRI-safe)
- Metallic implants (joint replacements, spinal fixation, surgical clips)
- History of welding / metal work — arrange X-ray orbits if concern
- Body piercings — remove or document (can cause burns)
- Tattoos — may cause heating (especially iron-based pigments)
- Transdermal patches — some contain metallic foil — remove before scan
- Pregnancy status — document LMP / pregnancy test if uncertain
- Claustrophobia — anxiolytic/sedation planning
- Renal function (eGFR) if gadolinium contrast planned
Practical Safety Steps
1Ask patient to complete MRI safety questionnaire in full
2Review form — query any uncertain responses with radiographer/radiologist
3Check device cards for all implantable devices — document model/serial
4Remove all removable metal: jewellery, piercings, hearing aids, hairpins, bra underwires
5Change patient into MRI gown (no metal fastenings)
6Confirm verbal consent for gadolinium if applicable
7Accompany to scanner room entrance — final verbal check with radiographer
💊Gadolinium Contrast — MRI
Gadolinium-Based Contrast Agents (GBCA)
- Paramagnetic agent — shortens T1 relaxation — bright on T1-weighted images
- Enhances vascular structures and areas with blood-brain barrier breakdown
- Indications: CNS tumours, MS plaques, vascular MRI, liver lesion characterisation
- Not routinely needed for MSK or basic brain MRI
- Less risk of acute reactions than iodinated contrast — but reactions can still occur
NSF — Nephrogenic Systemic Fibrosis
NSF: Rare but serious fibrosing condition affecting skin, joints, organs in severe CKD patients given gadolinium.
Risk threshold: eGFR <30 mL/min/1.73m²
Action: Avoid high-risk GBCA (group I agents); use minimum dose of group II/III agents or avoid entirely; nephrologist discussion
Dialysis patients: Early dialysis post-gadolinium if possible
GBCA Risk Classification
| Group | NSF Risk | Examples |
|---|
| Group I (High) | Highest | Gadodiamide (Omniscan), Gadoversetamide |
| Group II (Lower) | Lower | Gadobutrol (Gadovist), Gadoterate (Dotarem) |
| Group III (Intermediate) | Intermediate | Gadopentetate (Magnevist) |
Gadolinium Retention
Small amounts of gadolinium may be retained in brain, bone, and skin after repeated exposures — clinical significance uncertain. Prefer macrocyclic agents (Group II) to minimise retention. Use only when clinically indicated.
Acute Reactions to GBCA
- Less common than iodinated contrast reactions
- Management same as iodinated contrast — see Tab 5
- Pre-medication if prior GBCA reaction: prednisolone + antihistamine
☢️Nuclear Medicine — Principles & Radioisotopes
Nuclear medicine uses radioactive tracers (radiopharmaceuticals) injected/inhaled/swallowed. Detects physiological function, not just anatomy. Patient becomes a radiation source after administration.
Key Radioisotopes
| Isotope | Half-life | Use |
|---|
| Tc-99m | 6 hours | Most common — bone scan, V/Q, HIDA, sentinel node |
| F-18 FDG | 110 min | PET/CT — oncology, infection, cardiac |
| I-131 | 8 days | Thyroid treatment (ablation, thyroid cancer) |
| I-123 | 13 hours | Thyroid scintigraphy (diagnosis) |
| Ga-68 | 68 min | PET — neuroendocrine tumours, prostate (PSMA) |
| Tl-201 | 73 hours | Myocardial perfusion (older agent) |
Common Nuclear Medicine Scans
- Bone scan (Tc-99m MDP): Metastases, osteomyelitis, stress fractures — uptake where bone turnover high
- V/Q scan: Ventilation/perfusion — PE diagnosis (preferred over CTPA in young women, pregnancy)
- Thyroid scintigraphy: Thyroid nodule function (hot/cold), Graves disease
- PET/CT (FDG): Cancer staging/restaging — glucose avid tumours; also cardiac viability, infection (large vessel vasculitis)
- Renal scan (MAG3/DTPA): Differential renal function, obstruction, renovascular hypertension
- HIDA scan: Biliary function, cholecystitis (cystic duct obstruction)
- MIBG scan: Phaeochromocytoma, neuroblastoma
🛡️Radiation Protection in Nuclear Medicine Nursing
Three Principles of Radiation Protection
1. TIME — Minimise time spent close to patient; organise care efficiently before approaching
2. DISTANCE — Inverse square law: stand as far as practical; double distance = quarter dose
3. SHIELDING — Lead-lined syringes, lead glass screen, lead aprons where appropriate
Staff Exposure Thresholds (IAEA)
- Occupational limit: 20 mSv/year (averaged over 5 years)
- Pregnant staff: 1 mSv to fetus during pregnancy
- Public limit: 1 mSv/year
- Dosimetry badges mandatory for radiation workers
Nursing Care After Nuclear Medicine Procedures
Bodily fluids are radioactive for approximately 24 hours after administration of Tc-99m radiopharmaceuticals. Apply standard precautions with gloves.
- Wear gloves when handling urine, blood, emesis, saliva post-procedure
- Flush toilet twice after use by patient (first 24h)
- I-131 therapy patients: isolation room, dedicated toilet — radiation safety team protocols
- Discard contaminated items as radioactive waste per local policy
- Breast-feeding: pause for 24h (Tc-99m) or longer depending on agent — nuclear medicine team advises
- PET/CT patients (F-18): radiation very short-lived — 2h isolation usually sufficient
- Family / visitor distance: advise patients to avoid prolonged close contact (<1m) with young children and pregnant women for 24h (Tc-99m)
📡Fluoroscopy-Guided Procedures
Fluoroscopy Overview
- Real-time X-ray imaging — continuous or pulsed radiation
- Higher radiation dose than plain X-ray — dose management critical
- Staff must wear lead aprons + thyroid shields in fluoro suite
Barium Studies
- Barium swallow: Oesophageal disorders, dysphagia, achalasia; use water-soluble contrast (Gastrografin) if perforation suspected
- Barium follow-through: Small bowel Crohn's, malabsorption
- Barium enema: Largely replaced by colonoscopy/CT colonography
- Nursing: NPO pre-procedure, post-procedure constipation (pale stools for 1-2 days — warn patient), adequate hydration
ERCP (Endoscopic Retrograde Cholangiopancreatography)
- Combined endoscopic + fluoroscopic procedure
- Indications: CBD stones, biliary strictures, stenting, sphincterotomy
- IV iodinated contrast injected into biliary/pancreatic ducts
- Complications: Pancreatitis (most common 3-5%), cholangitis, bleeding, perforation
- Post-ERCP nursing: NPO until gag reflex returns, monitor amylase, obs chart, pain assessment, watch for fever/rigors
Angiography
- Arterial puncture (femoral/radial) — vascular access
- Diagnostic: coronary angiogram, cerebral angiogram, peripheral angiogram
- Therapeutic: angioplasty, stenting, embolisation
- Post-procedure nursing: puncture site haemostasis (manual pressure or closure device), neurovascular observations limb distal to puncture, 2-6h bed rest, adequate IV hydration
🏥Interventional Radiology (IR) — Nursing Care
Conscious Sedation Monitoring (IR Suite)
- Continuous SpO2, ETCO2 if available, ECG, NIBP every 5 min
- IV access patent — 18G minimum
- Resuscitation equipment immediately available
- Reversal agents available: Flumazenil (benzodiazepine reversal), Naloxone (opioid reversal)
- Pre-sedation: confirm fasting status (6h food / 2h clear fluids)
- Sedation nurse must have no other clinical duties during procedure
- Modified Aldrete score for post-sedation recovery assessment
IR Observation Ward — Post-Procedure Protocols
| Procedure | Observation Period | Key Monitoring |
|---|
| ERCP | 4–6 hours minimum | Pain, amylase, fever, haematemesis |
| Angioplasty / stenting | 4–6 hours | Haemostasis, distal pulses, BP |
| Biopsy (liver/renal) | 2–4 hours | Haematuria, abdominal pain, BP, Hb |
| Drainage insertion | 2–4 hours | Drain output, haemodynamics, pain |
| Embolisation | 6–24 hours | Post-embolisation syndrome: pain/fever/nausea |
| Thrombolysis / thrombectomy | Intensive monitoring | Bleeding risk, neuro obs (cerebral) |
💉Iodinated Contrast Reaction Management — Full Protocol
MILD
Nausea, vomiting, urticaria, pruritus, flushing
Actions:
✓ Stay with patient
✓ Reassure
✓ Monitor vital signs q15min
✓ Oral/IV antihistamine (cetirizine 10mg PO or chlorphenamine 4mg PO)
✓ Document and observe 30–60 min
✓ Escalate if worsening
MODERATE
Bronchospasm, laryngeal oedema, tachycardia, hypotension, facial swelling
Actions:
✓ Call for help
✓ IM Adrenaline 0.5 mg (1:1000)
✓ Nebulised salbutamol 2.5–5 mg
✓ IV access + IV fluids
✓ Supplemental O2 (15 L/min)
✓ Monitor SpO2, BP, ECG
✓ IV hydrocortisone 200 mg
✓ IV chlorphenamine 10 mg
SEVERE (ANAPHYLAXIS)
Cardiovascular collapse, severe bronchospasm, stridor, LOC
Actions:
✓ CALL RESUSCITATION TEAM
✓ IM Adrenaline 0.5 mg (1:1000) STAT — repeat 5-min
✓ Lie patient flat, raise legs
✓ IV 0.9% NaCl 500 mL bolus
✓ High-flow O2 — prepare airway equipment
✓ IV hydrocortisone 200 mg
✓ IV chlorphenamine 10 mg
✓ If cardiac arrest → CPR + AED
Note: Contrast reactions are anaphylactoid (non-IgE mediated) — they can occur on first exposure. Mechanism: direct mast cell degranulation. Management is identical to true anaphylaxis.
🛡️Pre-Medication for High Contrast Allergy Risk
When to Pre-Medicate
- Prior moderate/severe contrast reaction (relative — consider alternative imaging first)
- Known allergic asthma
- Multiple significant drug allergies
- Prior mild reactions: consider pre-medication if no alternatives
Pre-medication does NOT eliminate reaction risk — reduces severity/incidence. Document clearly. Radiologist must approve decision to proceed.
Pre-Medication Regimen
| Drug | Dose / Timing |
|---|
| Prednisolone | 30 mg PO: 13h, 7h, 1h before contrast |
| Cetirizine or Diphenhydramine | Cetirizine 10 mg PO 1h before; or Diphenhydramine 50 mg PO 1h before |
| Emergency/IV regimen | Hydrocortisone 200 mg IV 4h + 1h before; Chlorphenamine 10 mg IV 1h before |
- Use low-osmolality or iso-osmolar contrast agent
- Have resuscitation trolley at bedside during administration
- Medical cover must be immediately available
🩹Contrast Extravasation
Recognition
- Swelling at injection site during/after injection
- Pain or burning at IV site
- Skin tightness or blistering (severe)
- Injection pump pressure alarm
- Reduced flow on test injection
Risk Factors
- Small/fragile veins (elderly, chemotherapy patients)
- Peripheral or hand/foot IV sites
- Recent venepuncture proximal to current site
- Reduced venous return (axillary node dissection)
Management
1Stop injection immediately — do not remove cannula immediately
2Aspirate as much contrast as possible through cannula, then remove
3Elevate affected limb above heart level
4Apply cold compress (15-20 min each hour for first 6h) — reduces oedema
5Mark extent of swelling with skin marker — monitor for progression
6If >30 mL extravasated or blistering/skin necrosis risk → urgent surgical/plastics review
7Document: site, volume, contrast type, management, review plan
Most iodinated contrast extravasation resolves without intervention. True osmotic tissue injury is rare but possible with large volumes of high-osmolality contrast.
💊Metformin & CT Contrast — Critical Safety Point
EXAM KEY POINT: Metformin must be withheld before/after CT contrast in patients with eGFR <60 to prevent lactic acidosis.
Why Metformin is Held
- Contrast-induced AKI (even mild) can cause metformin accumulation
- Accumulated metformin → lactic acidosis (rare but potentially fatal)
- Lactic acidosis: high anion gap metabolic acidosis, mortality 50%
Current UK/ACR Guidance (2024)
- eGFR >60: No need to hold metformin routinely
- eGFR 45–60: Hold metformin on day of contrast and for 48 hours after — recheck eGFR before restarting
- eGFR <45: Hold metformin 48h before AND 48h after — restart only if eGFR stable
- Emergency contrast (any eGFR): If risk exceeds benefit — proceed, hold metformin, monitor renal function
Nursing Actions
- Identify all patients on metformin before contrast CT
- Check and document eGFR (recent blood test)
- Inform patient to hold metformin — provide written instructions
- Communicate to GP/prescriber for community patients
- Arrange eGFR recheck at 48h
- Do NOT restart metformin without medical review confirming stable renal function
Other antidiabetic medications (sulfonylureas, SGLT2 inhibitors, insulin): no specific hold required for contrast — but SGLT2 inhibitors may need holding for other reasons (e.g., euglycaemic DKA risk with surgical/stressful procedures).
🤰Pregnancy & Contrast Agents
Iodinated Contrast (CT)
- Both iodinated and gadolinium contrast cross the placenta
- Defer contrast CT if clinically possible — use alternative imaging (USS/MRI without contrast)
- If urgent life-threatening indication (CTPA for PE, aortic dissection): proceed — benefit far outweighs risk
- Theoretical risk: neonatal thyroid suppression from iodine load — check neonatal thyroid function after delivery if contrast given in third trimester
Gadolinium (MRI)
- Avoid gadolinium in pregnancy unless absolutely essential
- Crosses placenta — fetal exposure and theoretical risk of NSF (undeveloped kidneys) and gadolinium retention
- Non-contrast MRI is preferred in pregnancy — safe, no radiation
- If gadolinium essential: use minimum dose of macrocyclic agent, documented radiologist consent process
Breastfeeding
- Iodinated contrast: <1% excreted in breast milk, poorly absorbed by infant gut — safe to continue breastfeeding
- Gadolinium: Extremely small amount in breast milk — safe to continue breastfeeding (ESUR 2023 guidance)
- Some institutions advise expressing and discarding milk for 24h — patient choice
🌍GCC Healthcare Context — Diagnostic Imaging
Advanced Imaging Infrastructure in GCC
- Dubai & Abu Dhabi: World-class tertiary imaging — Cleveland Clinic Abu Dhabi, Sheikh Khalifa, Mediclinic, American Hospital Dubai
- Riyadh & Jeddah: King Faisal Specialist Hospital, KAMC — high-volume CT/MRI/PET-CT
- Doha: Hamad Medical Corporation — trauma centre, leading MRI availability
- Kuwait City, Muscat, Bahrain: Tertiary centres with modern imaging suites
- Private hospital sector in GCC: Extensive MRI/CT availability, often shorter wait times than public sector
PET-CT Oncology Services
- PET-CT centres growing rapidly in UAE (Dubai/Abu Dhabi) and Saudi Arabia
- Oncology volumes high — cancer increasing with ageing GCC population
- FDG PET/CT standard for lymphoma staging, lung cancer, colorectal
- Ga-68 PSMA PET for prostate cancer — available in major UAE/Saudi centres
GCC-Specific Clinical Considerations
Renal Impairment: Diabetes and hypertension are extremely prevalent in GCC populations — UAE/Saudi adult diabetes rates 15-20%+. Contrast precautions are especially critical. Always check eGFR before contrast CT.
Contrast Allergy: High rates of food and drug allergies reported in South Asian expat populations (large proportion of GCC healthcare workforce and patients). Allergy history documentation is essential.
Radiation Awareness: High CT utilisation in GCC EDs — growing awareness of cumulative radiation dose, particularly in children and patients with repeated imaging (trauma, oncology, IBD).
📜Regulatory & Competency Framework — GCC
DHA (Dubai)
- DHA Radiology Nursing Competencies: IV contrast administration, monitoring, reaction management
- DHA requires documented training in contrast safety for nurses administering IV contrast
- DHA licensing: registered nurses must demonstrate competency in diagnostic support nursing
- Dubai Radiology Information Systems (RIS/PACS) mandated in licensed facilities
DOH (Abu Dhabi)
- DOH Health Standards for diagnostic imaging facilities
- Radiology nursing scope includes patient preparation, contrast administration, safety screening, post-procedure care
- DOH requires radiation safety officer in all facilities with ionising radiation
- Abu Dhabi: Malaffi HIE (Health Information Exchange) — imaging results shared across providers
SCFHS (Saudi Arabia)
- SCFHS Imaging Nursing Standards — defines scope for radiology nurses in Saudi health system
- Competency framework includes: MRI safety screening, contrast management, radiation protection, procedural nursing in IR
- Vision 2030 Saudi Arabia: significant investment in imaging infrastructure and trained radiology nursing staff
- SCFHS licensing exam may include imaging nursing questions — critical topics below
📚DHA / DOH / SCFHS Exam Prep — High-Yield Topics
Contrast Reaction Management
- Drug for anaphylaxis from contrast: IM Adrenaline 0.5 mg (1:1000)
- Mild contrast reactions treated with: antihistamine + observation
- Contrast reaction is anaphylactoid (non-IgE) — can occur on first exposure
- Pre-medication: prednisolone + cetirizine/diphenhydramine
Metformin & Contrast (Exam Favourite)
- Hold metformin if eGFR <60 — day of and 48h post-contrast
- Risk: contrast → AKI → metformin accumulation → lactic acidosis
- Restart only after 48h with confirmed stable eGFR
Radiation Principles
- ALARA: As Low As Reasonably Achievable
- Time, Distance, Shielding — 3 principles of radiation protection
- Most vulnerable to radiation: first trimester fetus (organogenesis)
- Pregnant staff: dosimeter at waist; limit fetal dose to 1 mSv
MRI Contraindications (Exam Favourite)
- Absolute: cochlear implants, pacemaker/ICD (non-conditional), ferromagnetic foreign body in orbit
- Relative: first trimester pregnancy, claustrophobia, severe CKD for gadolinium
- MRI-conditional pacemaker: can proceed with specific protocol — cardiology must programme device before scan
- Insulin pumps: must be removed before MRI (not MRI safe)
Gadolinium & NSF
- NSF risk: eGFR <30 — avoid high-risk GBCA or avoid altogether
- Safe alternative: use macrocyclic agents (gadobutrol, gadoterate) at minimum dose
Hounsfield Units
- Air: –1000, Fat: –100 to –50, Water: 0, Blood: 50–70, Bone: >400
- Key: acute blood is hyperdense on CT head (bright white)
Post-Nuclear Medicine Nursing
- Bodily fluids radioactive 24h after Tc-99m — wear gloves
- I-131 patients require isolation — radiation safety protocols
🛠️Interactive Tool — Pre-Scan Safety Checklist Generator