dvt

DVT

• Deep venous thrombosis (DVT) is the presence of coagulated blood, a thrombus, in one of the deep venous conduits that return blood to the heart.

• The thrombus may become fragmented or dislodged and migrate to obstruct the arterial supply to the lung, causing a potentially life-threatening pulmonary embolus (PE).

• lower-extremity DVT is the most common venous thrombosis.

• Over a few months the thrombus resolves, partial recanalization occurs and collaterals develop.

predisposing factors for DVT

• Altered venous stasis, • Injury of the vascular wall, • Hypercoagulable state.

Events or conditions that alter the equilibrium of one or more of these factors may produce DVT.

Signs and symptoms• Swelling • Pain • Increased warmth • Red or discolored skin

Diagnostic tools• Ultrasound• X-ray venography• CT venography• MR venography• Nuclear studies

Ultrasonography• Ultrasonography is the current first-line imaging examination

for deep venous thrombosis (DVT) because

• Relative ease of use, • Absence of irradiation or contrast material.• High sensitivity and specificity

Grey and color Doppler features• Incompressibility• Loss of augmentation• Visualization• Doppler flow

limitationsPatient sizeExperience of the technologist performing the examination.The iliac and pelvic veins are not imaged consistently with

sonography.Interposed bowel gas may compromise duplex sonographic

examination of central iliocaval veins.False positive resultsFemoral vein duplication

X-ray venography• A venogram is an x-ray test that involves injecting x-ray

contrast material (dye) into a vein to shows how blood flows through veins.

Benefits• assess the status of a vein • find blood clots • assess varicose veins before surgery• find a vein in good condition to use for a bypass procedure or

dialysis access• stenting

Limitations• Costly• Time consuming• Patient discomfort due to needle puncture• Contrast agent• Radiation exposure

Radiological features• Acute thrombus :intraluminal filling defect in the contrast

opacified vein. • In chronic DVT, recanalization can result in a linear filling

defect in the vein, sometimes termed the tram-track pattern. The vein appears as if it were 2 small, paired veins.

Lower-extremity venogram shows a nonocclusive chronic thrombus. The superficial femoral vein (lateral vein) has the appearance of 2 parallel veins, when in fact, it is 1 lumen containing a chronic linear thrombus..

Computed Tomography• The CT finding of intraluminal thrombus is documented as a

filling defect on a delayed contrast-enhanced scan.

CTV

Normal CTV of pelvis and legs

 Shortness of breath in a 53-year-old man with acute myelogenous leukemia

M.R.I• Specific indications• Alternative to CT (particularly in patients with an allergy to

contrast material, in those with renal failure, and those in whom an evaluation of the iliocaval veins are required for questionable sonographic findings) or

• For a pre interventional evaluation of the extent of a thrombus

limitations• MRI cannot be used in patients with ferromagnetic implants • Claustrophobia• In general, MRI findings are subject to many artifacts that

simulate vascular disease. • based contrast agents have been linked to the development of

nephrogenic systemic fibrosis (NSF) or nephrogenic fibrosing dermopathy (NFD).

Magnetic resonance venogram (MRV) - axial view; A = lateral (transverse) sinus; B = sigmoid sinus; C = confluence of sinuses; and D = superior sagittal sinus.

38 yrs old lady presenting with severe headache giving hx of oral contraceptive pills

Nuclear Imaging

• Radiolabeled peptides that bind to various components of a thrombus have been investigated.

• Tc. Apcitide. Drawbacks.

• costly • The radiation dose is 6.8 mSv, equivalent to lower-extremity

CTV.

64yrs male heavy smoker

a 67-year-old man with cancer and symptoms of syncope

and hypoxia.

Thank You