Chest wall hematoma is a blood collection that accumulates in chest wall soft tissues or extrapleurally due to traumatic (blunt trauma, penetrating injury, rib fracture) or iatrogenic (surgery, biopsy, anticoagulant therapy) causes. On CT, acute hematoma shows high density (50-70 HU), density decreases in the subacute period, and becomes hypodense (20-30 HU) in the chronic phase. MRI signal characteristics follow hemoglobin degradation: acute phase T1 isointense/T2 hypointense (deoxyhemoglobin), subacute phase T1 hyperintense (methemoglobin — pathognomonic), chronic phase hemosiderin causes T2 hypointense rim. No solid enhancement is seen — this is an important differential criterion; however, thin peripheral (rim) enhancement may be seen in organized hematoma. Most resolve with conservative treatment; large or symptomatic hematomas may require surgical drainage.
Age Range
15-90
Peak Age
45
Gender
Male predominant
Prevalence
Common
Chest wall hematoma results from injury to intercostal arteries, intercostal veins, internal mammary artery, or small vessels within muscles. In blunt trauma, direct impact causes vascular injury; in rib fracture, costal fragments lacerate intercostal vessels. In iatrogenic cases, vascular injury occurs during surgery, tube thoracostomy, or transthoracic biopsy. In patients on anticoagulant therapy, even minor trauma can lead to large hematomas because the coagulation cascade is suppressed. The imaging findings of hematoma are directly related to the hemoglobin degradation process: (1) In the hyperacute/acute phase (0-48 hours), erythrocytes are intact containing oxyhemoglobin/deoxyhemoglobin — high density on CT results from the high electron density of hemoglobin's iron atom (Z=26); on MRI, the paramagnetic effect of deoxyhemoglobin causes T2 hypointensity. (2) In the subacute phase (3 days-4 weeks), hemoglobin oxidizes to methemoglobin — methemoglobin's 5 unpaired electrons create strong paramagnetic effect shortening T1 time and causing T1 hyperintensity (pathognomonic finding). (3) In the chronic phase (>4 weeks), hemoglobin degrades to hemosiderin — hemosiderin contains superparamagnetic iron deposits creating local magnetic field inhomogeneities and marked signal loss on T2*/GRE sequences (susceptibility effect).
The signature MRI finding of hematoma is the markedly hyperintense signal on T1-weighted images in the subacute phase. This finding results from methemoglobin's 5 unpaired electrons creating strong paramagnetic effect that shortens T1 relaxation time. T1 hyperintensity is pathognomonic in differentiating hematoma from seroma (T1 hypointense), abscess (T1 isointense-mildly hyperintense), and solid tumors (variable signal). It marks the subacute phase (3 days - 4 weeks).
On non-contrast CT in acute chest wall hematoma, high density of 50-70 HU is seen. The blood collection typically accumulates between ribs or within muscle planes in crescent (crescentic), lenticular (lens-shaped), or fusiform (spindle-shaped) configuration. Density within the hematoma may be homogeneous, but in the presence of active bleeding, lower-density serum components may be seen adjacent to high-density clot areas ('hematocrit effect') — this sentinel clot finding may suggest active hemorrhage. In the subacute phase (days-weeks), density progressively decreases (30-50 HU); in the chronic phase (weeks-months), the hematoma approaches serum density (10-30 HU) and eventually resolves. The highest density area of acute hemorrhage is typically closest to the bleeding source.
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A high-density (measurement: ___ HU) crescent/lenticular collection measuring ___ x ___ cm in the ___ region of the chest wall is seen, consistent with acute hematoma.
On contrast-enhanced CT in arterial phase, focal high-density contrast extravasation ('active bleeding sign' or 'contrast blush') may be seen within the hematoma if active bleeding is present. This finding appears as a focal area at arterial phase density (>90-100 HU) and may show spread on delayed phase. Active bleeding sign constitutes an indication for emergent intervention (embolization or surgery). In organized hematoma, thin peripheral rim enhancement may be seen — this reflects the vascular architecture of granulation tissue and should not be confused with active bleeding. Absence of solid enhancing components differentiates hematoma from solid tumors.
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Focal contrast extravasation at ___ HU density in the arterial phase is seen within the hematoma, consistent with active bleeding; emergent interventional or surgical evaluation is recommended.
On MRI, chest wall hematoma shows stage-dependent signal changes. In hyperacute phase (first few hours) erythrocytes are intact containing oxyhemoglobin — isointense on T1 (similar to muscle), mildly hyperintense on T2. In acute phase (1-3 days) deoxyhemoglobin predominates — isointense on T1, markedly hypointense on T2 (paramagnetic effect). In early subacute phase (3-7 days) intracellular methemoglobin forms — markedly hyperintense on T1 (PATHOGNOMONIC), hypointense on T2. In late subacute phase (1-4 weeks) extracellular methemoglobin predominates — hyperintense on T1, also hyperintense on T2 (erythrocyte lysis). In chronic phase (>4 weeks) hemosiderin deposition begins — hypointense rim on T1, markedly hypointense rim on T2 ('hemosiderin ring'). T1 hyperintensity is the most important MRI finding distinguishing hematoma from other collections (seroma, abscess).
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A collection measuring ___ x ___ cm in the ___ chest wall region showing hyperintense signal on T1 (methemoglobin content) is seen, consistent with subacute hematoma.
On T2-weighted images, hematoma shows variable signal depending on stage. In acute phase, deoxyhemoglobin's paramagnetic effect causes marked T2 hypointensity ('dark clot'). In early subacute phase, intracellular methemoglobin maintains T2 hypointensity. In late subacute phase, erythrocytes lyse releasing methemoglobin extracellularly — hyperintense signal on T2. In chronic phase, hemosiderin deposition creates peripheral T2 hypointense rim ('hemosiderin ring') — this finding traces old hemorrhages and can persist for months to years. On STIR sequence, subacute hematoma appears hyperintense and allows evaluation of surrounding edema. On GRE/T2* sequences, hemosiderin deposition causes marked susceptibility artifact (blooming).
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The collection showing ___ (hypointense/hyperintense/mixed signal) on T2-weighted images is consistent with ___ stage hematoma; peripheral hypointense rim suggests hemosiderin deposition.
On ultrasound, acute hematoma typically appears echogenic (bright) — fibrin networks and erythrocyte clusters in coagulated blood cause acoustic reflections. Over time, clot retraction and lysis cause the hematoma to become progressively more complex-appearing and hypoechoic. In subacute phase, mixed echogenicity (echogenic clot areas + hypoechoic/anechoic serum areas) is seen. In chronic phase, hematoma typically appears as anechoic or hypoechoic collection and may contain internal debris or septations. In organized hematoma, peripheral capsule may appear echogenic. No vascular flow is detected within hematoma on Doppler — this is an important differential criterion (solid tumors show vascular flow).
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A ___ (echogenic/mixed echogenicity/hypoechoic) collection measuring ___ x ___ cm in the ___ chest wall region is seen, with no internal vascular flow on Doppler; consistent with hematoma.
On contrast-enhanced MRI, no solid enhancement is seen within the hematoma — this is the most important criterion for differentiation from solid tumors. In organized (subacute-chronic) hematoma, thin peripheral rim enhancement may be seen; this reflects the neovascular architecture of granulation tissue. Rim enhancement should be thin and smooth — thick, nodular, or irregular rim enhancement suggests abscess or tumor. The non-enhancing internal area represents hematoma fluid. On diffusion-weighted images (DWI), acute/subacute hematoma may show high signal (viscous content, T2 effect) but this is T2 shine-through effect not true diffusion restriction — if true low ADC is absent on ADC map, diffusion restriction is excluded.
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No solid enhancement is seen within the collection on contrast-enhanced series, ___ (thin peripheral rim enhancement present/no enhancement); consistent with hematoma, no findings favoring solid neoplasm.
Criteria
Develops within 0-48 hours after trauma (blunt/penetrating); 50-70 HU high density on CT; T1 isointense, T2 hypointense (deoxyhemoglobin) on MRI
Distinct Features
Sentinel clot sign (highest density area within hematoma) may indicate bleeding source; association with rib fracture common; active contrast extravasation requires emergent intervention
Criteria
Develops after surgery, biopsy, or invasive procedure OR occurs spontaneously/with minimal trauma under anticoagulant therapy; usually large-sized; disproportionate size suggests anticoagulation
Distinct Features
Anticoagulant hematomas may rapidly enlarge and occur at multiple locations; INR/aPTT monitoring and anticoagulant adjustment critical; surgical hematomas typically localized to procedure site
Criteria
Hematoma older than 4 weeks; peripheral fibrous capsule developed; hypodense (10-30 HU) on CT; peripheral hemosiderin rim on MRI (T2 hypointense); rim enhancement possible
Distinct Features
May be confused with tumor due to rim enhancement and capsule formation; hemosiderin rim presence is old hemorrhage finding supporting diagnosis; size regression expected on follow-up imaging; biopsy rarely needed
Distinguishing Feature
Chondrosarcoma shows ring-and-arc calcification and solid enhancement; hematoma lacks calcification and solid enhancement; chondrosarcoma causes bone destruction, hematoma does not
Distinguishing Feature
Metastasis shows solid enhancement and grows on follow-up; hematoma shows no solid enhancement and shrinks on follow-up; metastasis has bone destruction, hematoma has hemosiderin rim; methemoglobin T1 hyperintensity confirms hematoma
Distinguishing Feature
Lipoma forms homogeneous fat-density mass (-50 to -100 HU); hematoma shows high density (50-70 HU) in acute phase, contains no fat; lipoma shows no time-dependent density change
Urgency
urgentManagement
conservativeBiopsy
Not NeededFollow-up
3-monthMost chest wall hematomas resolve with conservative treatment. In small, stable hematomas (no nutritional or neurological criteria), observation and pain control are sufficient. In large hematomas (>10 cm or symptomatic — respiratory distress, pain) or active bleeding, emergent intervention may be needed: angiographic embolization (intercostal artery hemorrhage) or surgical exploration/drainage. In anticoagulant-related hematomas, correction of coagulation parameters (vitamin K, protamine, idarucizumab, andexanet alfa) is priority. Follow-up imaging (3-6 weeks) should show hematoma size regression — absence of regression or growth should raise concern for solid neoplasm and biopsy should be planned. Rim enhancement of organized hematomas may be confused with tumor — clinical history and MRI methemoglobin finding are critical in differential diagnosis.
Chest wall hematomas generally resolve with conservative management (ice, compression, pain management). Active bleeding should be investigated in large or expanding hematomas (contrast-enhanced CT angiography). Anticoagulant dosing should be adjusted in patients on anticoagulation. Spontaneous hematomas without trauma history should be investigated for underlying coagulopathy or occult tumor (especially metastasis). Biopsy for tumor exclusion is needed for lesions that fail to resolve or are enlarging.