MRI Lower Limb Angiography (MR Angiogram - Lower Limb) Preparation, Findings (Normal & Abnormal)

MRI Lower Limb Angiography (MR Angiogram - Lower Limb)

What is MRI Lower Limb Angiography?

MRI Lower Limb Angiography is a non-invasive imaging technique used to visualize the arteries of the legs. It helps in evaluating blood flow and detecting vascular abnormalities without the need for catheter-based angiography.

🔍 Why is it Done? (Indications)

1. Peripheral Arterial Disease (PAD)

2. Claudication – Pain in legs while walking

3. Rest Pain or Non-Healing Ulcers

4. Pre-Surgical Planning (e.g., Bypass or Angioplasty)

5. Aneurysms or Vascular Malformations

6. Diabetic Foot Evaluation
   
   
   

   

   mri lower limb angio 

   
   

🧪 Preparation

• Fasting: Usually 4–6 hours prior

• Check Renal Function: If contrast is to be used (GFR > 30 mL/min preferred)

• Remove Metal Objects

• Consent for Gadolinium contrast (if applicable)

Technique

Scanner: 1.5T or 3T MRI
Coils: Peripheral vascular coil / body coil

Protocol:

1. Scout Images – Localizers

2. Pre-contrast sequences – T1/T2 local anatomy

3. Contrast-enhanced MR Angiography (CE-MRA):

   • Use Gadolinium-based contrast

   • Inject via power injector (e.g., 1.5 mL/sec)

   • 3-Station technique:

     • Aorta to thigh

     • Thigh to knee

     • Knee to ankle/foot

   • Bolus tracking or timing run is done for accurate arterial phase

4. Optional: Time-Resolved Angio (TWIST/TRICKS) for dynamic flow study

🧠 Findings (Normal & Abnormal)

✅ Normal: Smooth, uninterrupted arterial flow with normal caliber

❌ Abnormalities:

• Stenosis/Narrowing of arteries

• Occlusion (blockage)

• Collateral circulation

• Aneurysms

• Plaque or thrombus

MRI Urography (MR Urography)

There are three main types of urography, each using different imaging techniques to evaluate the urinary tract (kidneys, ureters, bladder):

1. X-ray :- (IVU) / Intravenous Pyelography (IVP)

2. CT Urography :- Contrast: Iodinated contrast

3. MRI :- MRI Urography (MRU)

1. Intravenous Urography (IVU) / Intravenous Pyelography (IVP)

🔹 Modality: X-ray
🔹 Contrast: Iodinated contrast injected IV
🔹 Use: 

• Classic method to evaluate kidney anatomy and function

• Detects stones, strictures, hydronephrosis
  🔹 ⚠️ Involves radiation and iodine contrast

2. CT Urography

🔹 Modality: CT Scan
🔹 Contrast: Iodinated contrast
🔹 Use:

• Excellent for detecting stones, tumors, hematuria causes

• Provides cross-sectional and 3D imaging
  🔹 ⚠️ Higher radiation dose

3. MRI Urography (MRU)

🔹 Modality: MRI
🔹 Contrast: Gadolinium (optional)
🔹 Use:

• No radiation

• Ideal for children, pregnant women, renal dysfunction

• Excellent soft tissue contrast, useful in tumors, anomalies
  🔹 🔹 Two types:
    - Static-fluid MRU (T2-weighted, no contrast)
    - Excretory MRU (T1-weighted with gadolinium)

•  Summary Table:

Type	Modality	Contrast Used	Radiation	Key Use Case
IVU / IVP	X-ray	Iodinated IV	Yes	Basic urinary tract evaluation
CT Urography	CT	Iodinated IV	High	Tumors, hematuria, stones
MRI Urography	MRI	Gadolinium (or none)	No	Pediatric, renal function, anomalies

MRI Urography non Contrast

 

•    MRI Urography (MR Urography)

Magnetic Resonance Urography (MRU) is a non-invasive imaging technique that uses MRI technology to visualize the kidneys, ureters, and bladder without radiation exposure.

Why MRI Urography is Done

MR Urography helps in evaluating:

1. Congenital anomalies – e.g., horseshoe kidney, duplex system

2. Obstruction – e.g., UPJ obstruction, ureteral stricture

3. Hydronephrosis – to assess cause and severity

4. Ureteric lesions – strictures, tumors, or calculi

5. Urinary tract infections (recurrent)

6. Post-surgical assessment – for ureteric reconstructions

7. Masses or tumors – of the kidney, ureter, or bladder

8. Vesicoureteral reflux (VUR) – indirectly seen

9. Renal function – with contrast-enhanced excretory phase

Types of MRI Urography

1. Static-fluid MR Urography

   • Heavily T2-weighted images

   • Good for dilated collecting systems

   • No contrast needed

2. Excretory MR Urography

   • T1-weighted post-contrast images

   • Evaluates renal function and excretion

   • Requires gadolinium contrast

Preparation

• Fasting 4–6 hours (for contrast studies)

• Adequate hydration

• Bladder filling may be needed for optimal visualization

• Check renal function (eGFR) before contrast use

Contraindications

• Renal impairment (eGFR <30) for contrast studies

• Implanted metallic devices not MRI-safe

• Claustrophobia (managed with sedation if needed)

Why Do MRI Renal Angiography? Advantages of MRI Renal Angiography

✅ Why Do MRI Renal Angiography?

MRI Renal Angiography (MRA) is a non-invasive imaging test that uses magnetic resonance imaging to visualize the renal arteries and veins. It is typically performed without ionizing radiation and often without iodinated contrast, making it safer for many patients.

🎯 Primary Indications:

1. 🩺 Renal Artery Stenosis (RAS):

   • To detect narrowing of the renal arteries (commonly due to atherosclerosis or fibromuscular dysplasia).

   • Important in evaluating secondary hypertension (especially in young patients or those with difficult-to-control BP).

2. 🩻 Renal Vein Thrombosis:

   • Identify clot formation in the renal vein (e.g., in nephrotic syndrome, trauma, or malignancy).

3. 🧬 Renal Artery Aneurysm or Dissection:

   • Evaluate aneurysmal dilatation or tears in the renal artery walls.

4. 🔍 Pre-Surgical or Pre-Transplant Evaluation:

   • To assess vascular anatomy before kidney surgery or transplant.

5. 🧪 Evaluation of Renovascular Hypertension:

   • Rule out vascular causes of high blood pressure due to compromised blood flow.

6. 🩹 Post-Interventional Follow-up:

• After stenting, angioplasty, or bypass surgery involving renal vessels.

why do mri renal angio

💡 Advantages of MRI Renal Angiography:

• No radiation exposure

• Good soft tissue contrast

• No need for iodinated contrast (can use Gadolinium) – safer for those with iodine allergy or renal insufficiency

• Can be done with or without contrast

⚠️ Limitations / Considerations:

• Gadolinium contrast may still carry risk in severe renal failure (risk of Nephrogenic Systemic Fibrosis)

• May be less detailed than CT Angiography for small vessel disease

• Contraindicated in patients with MRI-incompatible implants

MRCP Scan Preparation Guide (Magnetic Resonance Cholangiopancreatography)

MRCP Scan Preparation Guide (Magnetic Resonance Cholangiopancreatography)

 What is an MRCP?

MRCP is a special type of MRI scan that creates detailed images of the:

• Bile ducts

• Pancreatic ducts

• Gallbladder

• Liver

It helps detect:

• Gallstones

• Biliary obstruction

• Pancreatitis

• Tumors

✅ Patient Preparation Before MRCP

1. Fasting

• Do not eat or drink for at least 4–6 hours before the scan.

  • This reduces bowel contents and improves image clarity.

  • Especially important for visualizing bile and pancreatic ducts clearly.

2. No Contrast in Most Cases

• Most MRCP scans are done without contrast.

• However, sometimes a gadolinium contrast may be given if detailed liver or pancreas evaluation is needed.

3. Clothing & Accessories

• Wear loose, comfortable clothing without metal.

• Remove jewelry, watches, hairpins, or any metallic items.

• You may be asked to change into a hospital gown.

4. Medical History

Inform the technician or radiologist if you:

• Have a pacemaker, metal implants, or surgical clips

• Are claustrophobic (mild sedation may be offered)

• Are pregnant or breastfeeding

• Have kidney problems (if contrast is planned)

🧘‍♂️ During the Scan

• Lie still in the MRI machine for 20–30 minutes.

• You may be asked to hold your breath for a few seconds during imaging.

• It’s painless and non-invasive.

🕐 Duration:

• Total time: 30 to 45 minutes

• Scan time: 20–30 minutes

❌ What to Avoid Before MRCP:

• No eating, smoking, chewing gum, or drinking coffee/tea 6 hours before.

• Avoid heavy meals the night before.

💬 After the Scan

• No downtime; you can resume normal activities immediately.

• If contrast was used, drink water to flush it out.

MRI Elbow Joint Anatomy ligaments, tendon Common Elbow Pathologies on MRI

MRI Elbow Joint Anatomy

1. Bones

The elbow joint is formed by three bones:

• Humerus (upper arm)

• Ulna (forearm — medial side)

• Radius (forearm — lateral side)

Articulations:

• Humeroulnar joint: hinge movement (flexion/extension)

• Humeroradial joint: rotational movement

• Proximal radioulnar joint: supination/pronation

2. Ligaments

These provide stability to the elbow joint.

• Ulnar Collateral Ligament (UCL) / Medial Collateral Ligament (MCL)
  ➤ Prevents valgus stress (seen in throwing injuries)

• Radial Collateral Ligament (RCL) / Lateral Collateral Ligament (LCL)
  ➤ Prevents varus stress

• Annular Ligament
  ➤ Wraps around the radial head and holds it in place during rotation

3. Tendons

Tendons connect muscle to bone.

• Common Extensor Tendon (lateral epicondyle)
  ➤ Muscles for wrist extension (affected in Tennis Elbow)

• Common Flexor Tendon (medial epicondyle)
  ➤ Muscles for wrist flexion (affected in Golfer's Elbow)

• Distal Biceps Tendon (inserts on radial tuberosity)
  ➤ Elbow flexion and supination

• Triceps Tendon (inserts on olecranon)
  ➤ Elbow extension

4. Function

• Flexion/Extension (hinge action)

• Supination/Pronation (rotational movement)

• Stability for lifting, pushing, and rotation of the forearm

• Coordination between shoulder and wrist movements

MRI Appearance of Elbow Anatomy

Sequences:

• T1W: anatomy and bone marrow

• T2/STIR: fluid, edema, pathology

• PD FS: tendons, ligaments, cartilage

Common Elbow Pathologies on MRI

🔹1. Lateral Epicondylitis (Tennis Elbow)

• Degeneration or partial tear of the common extensor tendon

• T2 hyperintensity, tendon thickening, peritendinous edema

🔹 2. Medial Epicondylitis (Golfer’s Elbow)

• Involves common flexor tendon

• Similar MRI findings as above, but on the medial side

🔹 3. UCL Tear (Thrower’s Elbow)

• Common in athletes (baseball pitchers)

• Partial/complete tear; seen as discontinuity or high T2 signal in UCL

🔹 4. Biceps Tendon Tear (Distal)

• High T2 signal and gap at radial insertion

• May show tendon retraction

🔹 5. Triceps Tendon Tear

• Rare; seen in bodybuilders or trauma

• Disruption at olecranon insertion

🔹 6. Elbow Effusion

• Fluid in the joint capsule

• Non-specific, may indicate trauma, infection, or arthritis

🔹 7. Osteochondritis Dissecans (Capitellum)

• Common in adolescents

• Cartilage and subchondral bone injury seen on sagittal/axial T2

🔹 8. Ligament Injuries

• LCL or annular ligament sprains/tears

• May show increased signal, irregular contour, or avulsion

🔹 9. Nerve Compression (e.g., Cubital Tunnel Syndrome)

• Ulnar nerve compression at the elbow

• T2 hyperintensity, swelling of nerve

🔹 10. Fractures & Bone Contusions

• Seen as marrow edema on T2W/STIR

• Cortical disruption for fracture

 Summary Table

Structure	Function	MRI Pathology
UCL	Valgus stress resistance	Partial/complete tear
RCL	Varus stress resistance	Injury or laxity
Common Extensor Tendon	Wrist extension	Lateral epicondylitis
Common Flexor Tendon	Wrist flexion	Medial epicondylitis
Biceps/Triceps Tendons	Flexion/extension	Tendon rupture
Bones (humerus, ulna, radius)	Structure, motion	Fractures, OCD
Annular Ligament	Radial head stability	Subluxation, tear

What is Dynamic Angio in MRI? Why is MRI Brain with Dynamic Venography with Contrast done?

What is Dynamic Angio in MRI?

Dynamic Angiography in MRI (commonly referred to as Dynamic Contrast-Enhanced MRA or Time-Resolved MRA) is a specialized MRI technique used to visualize blood vessels dynamically over time—i.e., it captures a series of images as contrast flows through the vascular system.

Why it's called "Dynamic":

• Unlike static MRA (single snapshot), dynamic MRA captures multiple time frames after contrast injection.

• This allows visualization of arterial, capillary, and venous phases of blood flow—important for evaluating vascular timing, flow patterns, and pathology.

Why is MRI Brain with Dynamic Venography with Contrast done?

This is usually ordered when the clinician suspects a vascular abnormality involving the veins or sinovenous system of the brain. Here’s why:

1. Detect Cerebral Venous Thrombosis (CVT)

• Blood clots in venous sinuses may not show on non-contrast MRI.

• Dynamic contrast-enhanced MR venography shows how blood flows through the venous system, revealing blockages or slow flow.

2. Assess Arteriovenous Malformations (AVMs) or Fistulas

• Dynamic sequences show timing of contrast filling, helping differentiate between arteries and veins.

• Helps visualize abnormal connections or early venous drainage, characteristic of AVMs.

3. Evaluate Intracranial Hypertension

• Conditions like idiopathic intracranial hypertension (IIH) may involve transverse sinus stenosis, which is better seen with dynamic venography.

4. Detailed Mapping Before Surgery or Interventions

• Provides precise anatomy and timing of blood flow, guiding neurosurgical or endovascular planning.

Summary:

Technique	Purpose
Dynamic MRI Angio	Time-resolved imaging of arteries and/or veins during contrast injection.
MRI Brain with Venography (Dynamic Contrast)	Evaluates brain veins and sinuses over time — to detect clots, AVMs, fistulas, or venous stenosis.

MRI Brain Plain Venogram (Non-Contrast MRV)

1. MRI Brain Plain Venogram (Non-Contrast MRV)

➤ Technique:

• Typically done using Time-of-Flight (TOF) or Phase Contrast (PC) sequences.

• No contrast agent is used.

➤ Advantages:

• Non-invasive: No need for IV contrast.

• Useful for screening or follow-up of known conditions.

• Safe for patients with renal impairment or allergies to contrast.

➤ Limitations:

• May miss slow-flowing blood, especially in distal sinuses or small veins.

• Can be prone to artifacts (especially TOF in-plane flow saturation).

• Difficult in patients with motion or metallic implants.

2. Contrast-Enhanced MR Venogram (CE-MRV)

➤ Technique:

• Uses Gadolinium-based contrast agent.

• 3D T1-weighted imaging post-contrast injection (timed to venous phase).

➤ Advantages:

• More accurate visualization of venous structures, especially small veins.

• Less prone to flow-related artifacts.

• Can evaluate both anatomy and pathology like thrombosis or malformations better.

➤ Limitations:

• Requires IV access and contrast agent, which is contraindicated in:

  • Patients with GFR <30 (renal failure)

  • Known gadolinium allergy

• Slightly more expensive and time-consuming.

🎯 Clinical Indications for MR Venography:

• Suspected Cerebral Venous Sinus Thrombosis (CVST)

• Vascular malformations

• Evaluation of intracranial hypertension

• Follow-up of known venous pathology