Hemangiomas are common, benign growths of blood vessels. They can appear in various parts of the body, including the skin, muscles, bones, and internal organs. While many hemangiomas are harmless and resolve on their own, ultrasound, an imaging technique using sound waves, is an effective diagnostic tool for evaluating these vascular growths. This article explores its use in assessing hemangiomas.
Understanding Hemangiomas
Hemangiomas are benign tumors resulting from an abnormal proliferation of blood vessels. They are the most common benign tumor found in children, often presenting as “strawberry marks” on the skin, particularly on the face, scalp, chest, or back. While typically red or reddish-purple on lighter skin, they can appear brown on darker skin, or bluish if located deeper.
They can be present at birth or emerge within the first few months of life. Infantile hemangiomas undergo a rapid growth phase during the first year, followed by stabilization, and then gradual shrinking, or involution, during early childhood. Most superficial hemangiomas resolve by age 10, often leaving minimal trace.
Why Ultrasound is Used for Hemangiomas
Ultrasound is a preferred imaging method for hemangiomas. It is non-invasive and does not expose the patient to radiation, making it suitable for infants and children. It is also widely available and generally more cost-effective than other advanced imaging techniques like CT or MRI.
The utility of ultrasound extends to confirming the diagnosis of a suspected hemangioma and differentiating it from other lesions, such as vascular malformations. It allows for the assessment of the hemangioma’s size, depth, and precise location within tissues. Color Doppler ultrasound visualizes and evaluates blood flow patterns within the lesion, which is a distinguishing feature of hemangiomas. This makes it useful for monitoring growth or regression over time, and for ruling out potential complications.
What Happens During a Hemangioma Ultrasound
A hemangioma ultrasound is a straightforward and generally painless procedure requiring minimal preparation. For most external hemangiomas, no specific preparation like fasting is necessary. The patient lies on an examination table, and the area with the hemangioma is exposed.
A clear, water-based gel is applied to the skin over the hemangioma. This gel helps the small, handheld ultrasound transducer glide smoothly and ensures good sound wave transmission. The sonographer gently presses the transducer against the skin, moving it across the hemangioma and surrounding areas. The transducer emits high-frequency sound waves that travel into the body, bounce off tissues and structures, including the hemangioma, and return to the transducer.
These sound waves are converted into real-time images displayed on a monitor. During the scan, the patient might feel slight pressure but no pain. The procedure typically lasts 15 to 30 minutes, depending on the hemangioma’s size and location, and is well-tolerated even by infants. The sonographer may ask the patient to remain still or hold their breath briefly for clearer images.
What Ultrasound Images Reveal
Ultrasound images provide characteristics for diagnosing and monitoring hemangiomas. On grayscale ultrasound, hemangiomas typically appear as well-defined solid masses with mixed echogenicity (varying shades of gray). They are often hyperechoic (brighter than surrounding tissue), but can also be hypoechoic (darker) or isoechoic (similar brightness), sometimes identified by a hyperechoic rim.
Their internal texture can be homogeneous or heterogeneous. Ultrasound offers high diagnostic accuracy, helping distinguish hemangiomas from other masses. Color Doppler ultrasound is useful for detecting characteristic high blood flow within the hemangioma, often showing prominent internal vascularity with high-flow arterial and low-resistance venous waveforms. Peripheral feeding vessels may also be observed.
This distinct vascular pattern, along with features like compressibility, helps differentiate hemangiomas from other vascular abnormalities or solid tumors. For instance, a lack of detectable blood flow on Doppler ultrasound helps distinguish hepatic hemangioma from hepatocellular carcinoma, which typically exhibits intra- or peritumoral vascular signals. In some cases, contrast-enhanced ultrasound (CEUS) using microbubbles can further improve diagnostic accuracy by demonstrating typical enhancement patterns like peripheral nodular contrast enhancement and progressive centripetal filling. These detailed findings are crucial for confirming diagnosis, tracking changes, and guiding treatment strategies.