Liver/Spleen & Hemangioma Imaging⁹⁹ᵐTc-sulfur colloid · ⁹⁹ᵐTc-RBC
Sulfur-colloid reticuloendothelial imaging and Tc-99m-RBC for hepatic hemangioma
Quick Answer
Two classic reticuloendothelial/blood-pool studies retain specific niche roles. Tc-99m-sulfur colloid is taken up by Kupffer cells (liver), spleen, and marrow — useful for characterizing focal nodular hyperplasia (FNH) (which contains Kupffer cells and may retain colloid), detecting splenosis/accessory spleen (with heat-damaged RBCs), and assessing colloid shift. Tc-99m-labeled RBC imaging characterizes hepatic hemangioma by its hallmark perfusion–blood-pool mismatch with delayed fill-in.
Mechanism & Physiology
- Tc-99m-sulfur colloid particles are cleared by the reticuloendothelial (mononuclear phagocyte) system — Kupffer cells in the liver (~85%), splenic and marrow macrophages (~10%/5%). Uptake therefore maps functioning RES, not hepatocytes or vasculature: most focal liver lesions (metastases, HCC, adenoma, cysts) lack Kupffer cells and appear photopenic (cold), whereas FNH — which contains Kupffer cells — can be iso- or hyperintense, the basis of its characterization.
- Tc-99m-labeled RBC stays in the blood pool; a hemangioma is a slow-flow vascular space, so it is hypoperfused early yet accumulates blood-pool tracer on delayed images (the "fill-in"). SPECT (or SPECT/CT) is essential for small lesions.
- Heat-damaged (denatured) RBC are selectively sequestered by the spleen, making them specific for splenic tissue.
Sulfur Colloid (Reticuloendothelial)
- Normal: homogeneous liver and spleen uptake. A colloid shift (increased spleen/marrow relative to liver) signals hepatocellular dysfunction / portal hypertension (cirrhosis) — often with relative caudate-lobe hypertrophy and heterogeneous liver uptake.
- FNH: normal or increased colloid uptake (Kupffer cells) — a helpful discriminator from adenoma (usually cold) and malignancy.
- Superscan-equivalents: diffuse marrow uptake in myeloproliferative/infiltrative states.
- Heat-damaged RBCs (splenic-specific) localize accessory spleen, splenosis, and confirm a left-upper-quadrant mass as splenic.
Tc-99m-RBC Hemangioma Study
Performed as a triple-phase study — flow, immediate blood-pool, and delayed (1–2 h) blood-pool with SPECT. The hallmark is perfusion–blood-pool mismatch: decreased/normal flow but progressive "fill-in" on delayed images — a near-specific finding for lesions above ~1.5–2 cm (smaller lesions fall below SPECT resolution → partial-volume false negatives). A lesion that is hot on flow argues against hemangioma (suggests a hypervascular tumor).
Reporting & Differential
- Colloid: report liver/spleen homogeneity, colloid shift, and any lesion's colloid avidity (FNH vs cold lesion).
- RBC: report the flow/blood-pool pattern and whether it meets the mismatch-with-fill-in criterion for hemangioma.
- Differential of a cold colloid lesion: metastasis, HCC, adenoma, cyst, abscess — non-specific, so correlate with cross-sectional imaging; FNH is the discriminating warm/hot lesion.
Two RES/blood-pool studies with specific answers
Two classic studies keep niche roles. Tc-99m-sulfur colloid images Kupffer cells (liver), spleen, and marrow: a colloid-avid lesion favors FNH (which contains Kupffer cells) over adenoma/malignancy, colloid shift to spleen/marrow signals hepatocellular dysfunction/portal hypertension, and heat-damaged RBCs specifically localize accessory spleen/splenosis. Tc-99m-labeled RBC imaging characterizes hepatic hemangioma by its near-specific perfusion–blood-pool mismatch with delayed fill-in (SPECT, lesions above ~1.5–2 cm).
Colloid maps functioning RES: most focal lesions lack Kupffer cells and read cold, so colloid avidity is the discriminator that favors FNH over adenoma/malignancy. A colloid shift to spleen/marrow (with heterogeneous liver ± caudate hypertrophy) is a classic cirrhosis/portal-hypertension signature.
For hemangioma, the diagnostic criterion is a triple-phase perfusion–blood-pool mismatch with delayed SPECT fill-in; a lesion hot on the flow phase argues against hemangioma (hypervascular tumor). Heat-damaged RBC imaging is splenic-specific — the definitive test for accessory spleen/splenosis and for proving a mass is splenic. These are now second-line to MRI/CT but remain problem-solvers where those are equivocal or contraindicated.
High-Yield Pearls
- Perfusion–blood-pool mismatch with delayed fill-in = hemangioma on triple-phase RBC SPECT.
- Colloid-avid liver lesion favors FNH (Kupffer cells) over adenoma/malignancy; most other lesions are cold.
- Colloid shift to spleen/marrow = hepatocellular dysfunction/portal hypertension.
- Heat-damaged RBC imaging is the specific test for accessory spleen/splenosis.
Common Pitfalls
- Small hemangiomas (<1.5 cm) below SPECT resolution (partial-volume false negative).
- A lesion hot on flow misread as hemangioma (suggests hypervascular tumor).
- Over-relying on colloid uptake alone to diagnose FNH without correlative cross-sectional imaging.
Related Pages
- Related: hepatobiliary imaging; pitfalls: Pearls, pitfalls & normal variants.
Self-Check
Q1. What Tc-99m-RBC pattern is near-specific for hepatic hemangioma?
Answer: Perfusion–blood-pool mismatch with delayed fill-in — decreased/normal flow but progressive activity on delayed blood-pool imaging (SPECT, lesions above ~1.5–2 cm).
Q2. Why might focal nodular hyperplasia retain sulfur colloid?
Answer: FNH contains Kupffer cells, which take up colloid — helping distinguish it from adenoma/malignancy.
Q3. Which test specifically localizes accessory spleen or splenosis?
Answer: Heat-damaged (denatured) RBC imaging — splenic-specific uptake.
Q4. What does a "colloid shift" to spleen and marrow indicate?
Answer: Hepatocellular dysfunction / portal hypertension — reduced hepatic Kupffer-cell uptake redistributes colloid.
Evidence & sources
https://nuc.med/liver-spleen-imaging/ Report an issue