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CT Venography (Pelvis / Lower Extremities)

CTA+ ContrastVascular
Indications
  • Suspected iliocaval or iliofemoral DVT (especially where ultrasound is limited: pelvic veins, IVC)
  • May-Thurner syndrome (left common iliac vein compression)
  • Chronic venous obstruction, pre-/post-venous stent evaluation
  • Pelvic congestion syndrome workup; venous mapping
  • IVC filter assessment
Patient prep
  • Screen eGFR/contrast allergy; premedicate if indicated
  • IV access 18-20 G (antecubital)
  • Supine, arms up
Contrast
Agentiodinated (e.g. iohexol 350 or iopamidol 370)
RouteIV (indirect venography — venous return after systemic circulation)
Dose≈100-150 mL at ~4 mL/s; saline chaser typically omitted
TimingSingle venous acquisition at a fixed delay: ~120 s for pelvis, ~110-120 s when covering through the popliteal veins
Technique
  • Supine, arms up; coverage IVC confluence/diaphragm through the pelvis, extending through the popliteal veins for lower-extremity DVT
  • Fixed-delay indirect technique — venous opacification is inherently fainter than arterial; review with a narrower window
  • 120 kV; dose modulation; 2-3 mm axial with coronal reformats; thin source for problem-solving
  • Can be combined with CTPA as a single exam for PE + DVT when clinically appropriate
Series / Sequences
#Series / SequencePlaneThicknessNotes
1Venous-phase axialaxial2-3 mm~110-120 s fixed delay; filling defects, wall thickening
2Coronal reformatcoronal2-3 mmIliac vein compression, IVC survey
3Thin axial sourceaxial1-1.25 mmProblem-solving, stent assessment
Key points
  • Indirect CTV uses a long fixed delay (~2 min) — patience beats bolus tracking here; even so, flow-related mixing artifact can mimic thrombus, confirm on multiple planes
  • Best test for pelvic/iliocaval segments that duplex ultrasound cannot see; assess left common iliac vein compression between right common iliac artery and spine (May-Thurner)
  • Acute thrombus: central filling defect distending the vein; chronic: retracted vein, wall thickening, collaterals
  • Ultrasound remains first-line for femoropopliteal DVT — reserve CTV for pelvic extension, inconclusive duplex, or anatomic mapping
References
• ACR–NASCI–SIR–SPR Practice Parameter for the Performance and Interpretation of Body CT Angiography link
• ACR Appropriateness Criteria: Suspected Lower Extremity Deep Vein Thrombosis link
• Radiopaedia: Deep vein thrombosis link
Source: Researched — verify against your institution
‹ PreviousRenal Scan (Tc-99m MAG3 +/- Lasix)
Reference template — verify and adapt to your scanner, vendor and institution before clinical use. Not a substitute for clinical judgment.