Contrast Extravasation

(For CT / MRI Contrast Administration – Radiology Practice)

Contrast extravasation is the unintentional leakage of contrast media from a vein into surrounding soft tissue during injection.

It is most commonly associated with iodinated contrast in CT, but may also occur with gadolinium contrast in MRI.

---

✅ Prevention of Contrast Extravasation

1️⃣ Patient Assessment (Before Injection)

• Assess vein quality

• Avoid:

  • Fragile veins (elderly, oncology patients)

  • Post-mastectomy side

  • Lymphedema limb

  • Dialysis fistula arm

• Review patient history:

  • Diabetes

  • Chemotherapy

  • Steroid use

  • Peripheral vascular disease

---

2️⃣ Proper IV Cannulation

• Use appropriate cannula size:

  • CT power injection → 18–22G (depending on protocol)

• Choose:

  • Large, straight vein in antecubital fossa

• Avoid:

  • Hand veins (for high flow injection)

  • Small or tortuous veins

• Secure cannula properly

---

3️⃣ Before Starting Injection

• Check:

  • Blood return

  • Flush with normal saline

  • No swelling or resistance

• Confirm patient comfort

• Educate patient:

  “Tell us immediately if you feel pain, burning, or swelling.”

---

4️⃣ During Injection

• Monitor injection site visually (if possible)

• Communicate with patient

• Watch for:

  • Swelling

  • Pain

  • Tightness

  • Injection pump high-pressure alarm

---

5️⃣ High-Risk Patients

Extra caution for:

• Pediatric patients

• Elderly

• Unconscious / sedated patients

• Patients with poor sensation

---

🚨 Signs of Contrast Extravasation

• Swelling at injection site

• Pain or burning sensation

• Skin tightness

• Redness

• High injection pressure alarm

• Severe cases: blistering or skin discoloration

---

🏥 Immediate Management (Treatment)

1️⃣ STOP Injection Immediately

• Stop power injector

• Disconnect tubing

---

2️⃣ Leave Cannula in Place (Initially)

• Attempt gentle aspiration of contrast (if possible)

---

3️⃣ Elevate the Limb

• Elevate affected extremity above heart level

---

4️⃣ Apply Cold Compress

• Apply for 15–20 minutes

• Repeat every few hours for 24 hours

Cold helps reduce inflammation and pain.

(Some institutions may use warm compress after 24 hours depending on protocol.)

---

5️⃣ Assess Severity

Mild (Most Common)

• < 50 mL

• Mild swelling

• No skin compromise
  👉 Conservative treatment

Moderate

• Increasing swelling

• Pain

• Limited movement
  👉 Observe closely, document, inform radiologist

Severe (Rare but Emergency)

• Severe pain

• Skin blistering

• Compartment syndrome signs:

  • Increasing pain

  • Numbness

  • Decreased pulse

  • Pale skin

👉 URGENT surgical referral

---

📋 Documentation (JCI / MOH Compliance)

• Amount of contrast extravasated

• Type of contrast

• Injection rate

• Site

• Patient symptoms

• Actions taken

• Radiologist notification

• Follow-up instructions

Incident report required.

---

⚠️ When to Refer to Surgery

• Extravasation > 100 mL (relative criteria)

• Severe pain

• Skin necrosis

• Neurovascular compromise

• Compartment syndrome suspicion

---

👩‍⚕️ Patient Instructions Before Discharge

• Elevate limb

• Apply cold compress

• Return immediately if:

  • Increasing pain

  • Numbness

  • Blistering

  • Skin color change

Provide written instruction sheet.

---

🔬 Complications (Rare)

• Skin necrosis

• Compartment syndrome

• Infection

• Chronic pain

---

🎯 Key Message for Radiology Technologists

Early detection + Immediate action = Prevent serious complication.

Most extravasations are mild and resolve without long-term effects if managed properly.

CT Calcium Scoring

What is reveal for these images?

SagT2 FS 

Sag T2FS

Sag T2

 

What is the diagnosis of this patient ? History got accident for a week .

 

How to Understanding MRI Pulse Sequence Part 1/ការយល់ដឹងពីការប្រើ MRI Pulse sequence https://youtu.be/f87ElhJXjcg

History of MRI

Timeline of MRI :

1. 1946 MR Phenomenon by Bloch & Purcell. 

2. 1950 NMR develoed as ananlytical tool

3. 1952 Nobel Prize of Bloch and Purcell.

4. 1972  Computerized Tomography .

5. 1973 Backprojection MRI -by Lauterur.

6. 1975 Fourier Imaging by Ernst .

7. 1980 MRI Spin Warp imaging .

8. 1986 Gradient Echo Imaging , NMR Microscope .

9. 1988 Angiography .

10. 1991 Nobel Prize R.R Ernst .

11. 1992 Fuctional Imaging 

Paramagnetic Contrast

Gadolinium

gadolinium (Gd) are the most widely used of all MR contrast agents. Because of its unique electronic structure (described below), Gd is strongly paramagnetic.

Paramagnetism is an intrinsic property of certain materials to become temporarily magnetized when placed in an external magnetic field. In fact, Gd is one of only four elements that can be magnetized at room temperature (the other three being iron, nickel, and cobalt).

The powerful paramagnetic properties of Gd make it extremely useful as an MR contrast agent. Gadolinium is not directly seen in an MR image, but manifests its presence indirectly by facilitating the relaxation of nearby hydrogen protons. Gd preferentially shortens T1 values in tissues where it accumulates rendering them bright on T1-weighted images.

Paramagnetism may exist over a wide dimensional range — from subatomic particles to atoms to entire molecules. Nuclear paramagnetism, the form responsible for the NMR phenomenon, is extremely weak except in the immediate vicinity of the nucleus. It plays little or no role in determining the gross paramagnetic properties of entire atoms like gadolinium.

The form of paramagnetism exhibited by gadolinium compounds derives from electrons, not protons, and is known as Curie paramagnetism. Because of electrons have the same spin (½) but a much smaller size than protons, their gyromagnetic ratios are 657 times larger. If these electrons remain unpaired in shells or bonding orbitals, the unbalanced spins produce a strong magnetic moment capable of inducing magnetic relaxation in nearby nuclei. This is the origin of the bulk paramagnetism possessed by elements such as gadolinium. 

Gadolinium has atomic number 64 on the periodic table. It occupies the central position in the lanthanide series of elements. Lanthanides are rare-earth metals grouped chemically because they possess partially filled inner shells of electrons (4f and 5d subshells). 

The electronic structure of the neutral Gd atom is shown right. Note the 7 unpaired electrons in its 4f subshell that account for the element's strong paramagnetism. In its ionized state, Gd⁺³ donates its 6s² and 5d¹electrons for bonding, leaving its 4f⁷electron shell intact. The powerful magnetic moment of Gd is therefore largely maintained even when chelated to a ligand such as DTPA in a contrast agent formulation.