Tumor margins and malignant grade are best defined by vascular imaging modalities such as Doppler flow or contrast enhancement combined with videomicroscopy. The following are image-guided treatment options that can be performed on breast, prostate, liver, and skin cancers.
NEW DOPPLER APPLICATIONS
Blood vessel mapping using the various Doppler modalities is routinely used in both cancer treatment and reconstructive planning. In cancer surgery, it is critical to locate aberrant veins or arterial feeders in the operative site so postoperative blood loss is minimized. Advanced 3D Doppler systems allow for histogram vessel density measurement of neoplastic angiogenesis.
SOLID ORGAN CANCER IMAGING UPDATES
Breast cancer, invading the lower dermis and nipple, discovered with high-resolution probes signifies the tumor has outflanked clinical observation essential for detecting the newly discovered entity of breast implant-associated anaplastic large cell lymphoma (BIA-ALCL). This capability is also vital for diagnosing the recent epidemic of male breast cancers arising near the mammographically difficult nipple areolar complex, occurring in our 911 First Responders.
For prostate cancer, 4D ultrasound can identify low-grade cancer delimited by the capsule and with low vessel density, and should be followed serially at 6-month intervals.
CONTRAST-ENHANCED ULTRASOUND (CEUS)
In 1990, Dr. Rodolfo Campani developed ultrasound contrast for liver imaging and Drs. Cosgrove (London) and Lassau (Paris) extended the use to breast, skin, and prostate tumors. CEUS is currently used worldwide but is not Food and Drug Administration (FDA)-approved in the United States.
One use for CEUS is microbubble neovascularity, which demonstrates therapeutic response since the Response Evaluation Criteria in Solid Tumors (RECIST) studies noted tumor enlargement during treatment might be related to cell death with cystic degeneration or immune cell infiltration destroying malignant tissue. Doppler ultrasound or CEUS reliably verifies decreased angiogenesis in place of contrast CT or dynamic contrast-enhanced (DCE) MRI. If vascular perfusion ceases, thermal treatments, such as cryotherapy, high-intensity focused ultrasound (HIFU), or laser ablation, should be completed.
Four-dimensional (4D) ultrasound imaging is real-time evaluation of a 3D volume so we can show the patient immediately the depth and the probability of recurrence. Specific echoes in skin cancer generated by nests of keratin are strong indicators of aggression and analyzed volumetrically. Highly suspect areas are checked for locoregional spread and a search is performed for lymphadenopathy so we can determine if the disease is confined and whether further surgical intervention is unlikely at this time. Patients are reassured because they simultaneously see the exam proceed in systematic stages. In serious cases, the patient is forewarned that the operation involves skin grafts and tissue construction. 4D ultrasound permits image-guided biopsy of the most virulent area of the dermal tumor and allows the pathologist to focus on the most suspicious region of the lymph node mass excised from the armpit, neck, or groin. Some laboratories are using postop radiography and sonography for better specimen analysis.
VIDEO DIGITAL MICROSCOPY VS BIOPSY
Fear of complications can deter patients from seeking medical opinion and surgical intervention, so many opt for noninvasive options. Imaging can help to reduce unnecessary biopsies because it can help identify the 1 out of every 33,000 moles that is malignant, while weeding out those that are not.
Once skin cancer is diagnosed, the treatment depends on depth penetration, possibly involving facial nerves, muscles around the eye and nasal bone or ear cartilage. Verified superficial tumors are treated topically or by low dose non-scarring radiation. Many cancers provoke a benign local immune response or coexistent inflammatory reaction that simulates a much larger area of malignancy, and cicatrix accompanies the healing response. 4D imaging combined with optical microscopy (RCM (reflectance confocal microscopy) or OCT (optical coherence tomography)) defines the true border during surgery, sparing healthy tissue, resulting in smaller excisional margins and less scar formation.
Do you have any tips on incorporating ultrasound in cancer imaging? Comment below, or, AIUM members, continue the conversation on Connect, the AIUM’s online community.
Robert Bard, MD, DABR, FASLMS, currently runs a private consulting practice in New York City. He authored Image Guided Dermatologic Treatments, Image Guided Prostate Cancer Treatment, and DCE-MRI of Prostate Cancer and is a member of multiple leading international imaging societies. Since 1972, Dr. Bard has pioneered digital imaging technologies as alternatives to surgical biopsies for dermatologic and solid organ neoplastic disease.