Lee, Christine U.

AbstractBackgroundHigh dose rate brachytherapy is commonly used in the treatment of prostate cancer. Treatment planning is often performed under transrectal ultrasound (US) guidance, but brachytherapy needles can be challenging to digitize due to the presence of poor US conspicuity and imaging artifacts. The plan accuracy and quality, however, are dependent on the proper visualization of the needles with millimeter accuracy.PurposeThis work describes a technique for generating a color overlay of needle locations atop the grayscale US image. Prototype devices were developed to produce vibrations in the brachytherapy needles that generate a high contrast color Doppler (CD) signal that highlights the needle locations with superior contrast and reduced artifacts. Denoted by the acronym color VISION (Vibrationally Induced Shimmering for Identifying an Object's Nature), the technology has the potential to improve applicator conspicuity and facilitate automated applicator digitization.MethodsThree prototype vibrational devices with frequencies between 200–450 Hz were designed in‐house and evaluated with needle implants in a phantom and cadaveric male pelvis using: (1) an actuator attached to the front of a prostate needle template; (2) an actuator attached to the top of the needle template; and (3) a hand‐held actuator with a stylet, inserted directly into a needle's inner lumen. Acquired images were postprocessed in MATLAB to evaluate the potential for automated digitization.ResultsAll prototype devices produced localized shimmering in implanted brachytherapy needles in both the axial and sagittal planes. The template mounted actuators provided better vibrational coupling and ease of operation than the stylet prototype. The Michelson contrast, or visibility, of the shimmering CD signal was 100% compared with ≤40% for B‐mode imaging of a single needle. Proof‐of‐principle for automated applicator digitization using only the CD signal was demonstrated.ConclusionsThe color VISION prototype devices successfully coupled mechanical vibrations into brachytherapy needles to generate US CD shimmering and accurately highlight brachytherapy needle locations. The high contrast and natively registered signal are promising for future work to automate the needle digitization and provide a real‐time visual overlay of the applicator on the B‐mode US image.

Idiopathic granulomatous mastitis (IGM) is a rare, benign inflammatory disorder of the breast that is often underrecognized. The exact etiology and pathophysiology are unknown, but milk stasis is felt to play a role. Classically, this condition is noninfectious, but many cases are noted to be associated with Corynebacterium species. Most patients affected are parous women with a mean age of 35, and many have breastfed within five years of diagnosis. Patients typically present with a painful mass and symptoms of inflammation, and these features can sometimes mimic breast cancer. Biopsy is needed to make a definitive diagnosis, and noncaseating granulomas are found on core biopsy. Many patients have a waxing and waning course over a period of six months to two years. Goal of treatment is to avoid surgery given poor wound healing, high risk of recurrence, and poor cosmetic outcomes. Medical treatment is preferred and includes observation, antibiotics, steroids, and immune modulators such as methotrexate. In more recent years, topical and intralesional steroids have become the treatment of choice, with similar outcomes to oral steroids.

Summary: Lymphaticovenous anastomosis (LVA) surgery is an effective surgery for the treatment of lymphedema in the extremities. Indocyanine green lymphography is the reference standard for visualizing lymphatics for LVA surgery, but it has several limitations; most notably, superficial dermal congestion can mask deeper lymphatic vessels. To overcome the limitations, we add contrast-enhanced ultrasound (CEUS) lymphography. We have previously reported that CEUS lymphography can identify lymphatic vessels for LVA surgery that indocyanine green lymphography does not. Here, we describe how we perform CEUS lymphography, including workflow, technique, and documentation. Before informed consent, the patient must be screened for possible adverse reactions to microbubbles. The procedure involves multiple intradermal injections of the microbubble agent at various sites along the extremity. After each injection, imaging for microbubble uptake by lymphatic vessels is performed using an ultrasound scanner with contrast-specific software. We use sulfur hexafluoride lipid-type A microspheres (Lumason/SonoVue; Bracco Suisse SA), but we are investigating the performance of other Food & Drug Administration–approved microbubble agents for CEUS lymphography. Having a systematic approach to marking the skin can mitigate the hindrance of marking over ultrasound coupling gel. Another benefit of CEUS lymphography is the rapid identification of neighboring veins compatible in size and location for anastomosis. We hold regular scheduled multidisciplinary meetings for coordination of care, discussion of outcomes, quality assurance, and ongoing innovation.

The color Doppler twinkling artifact has been attributed to existing microbubbles or cavitation occurring on objects like kidney stones, some breast biopsy markers, and sandpaper. The grooves of helical constructs that twinkle may provide sufficient locations for bubble retention and/or cavitation. We developed six half-cylinders that replicate the geometry of twinkling helical constructs with a micro 3D-printing process to explore how their characteristics relate to twinkling. Four copies of each design including a control were created. The cylinders had pitch (groove-to-groove distance) of 87.5–343 μm and amplitude (groove depth) of 41.5–209 μm. The cylinders were submerged in degassed water and optically imaged before and after ultrasound to visualize bubbles on the cylinders. The cylinders remained submerged while scanning with color Doppler at frequencies from 3.1 to 6.3 MHz with a General Electric Logiq E9 scanner and 9L linear array transducer. Two designs that showed twinkling characteristics were further examined. The presence or absence of bubbles on these designs was confirmed with microscopy, and the resulting twinkling behavior was investigated. This work shows strong evidence that both existing visible bubbles and either cavitation or ultrasound wave interactions with patterned or rough surfaces are significant factors in producing the twinkling signature.

AbstractBackgroundApplicator conspicuity in ultrasound‐guided brachytherapy procedures is commonly impaired by imaging artifacts or non‐ideal imaging geometry, which can slow down applicator position digitization and increase the geometric uncertainty of the delivered dose distribution.PurposeThe purpose of this study was to improve the conspicuity of high‐dose rate (HDR) brachytherapy needles under B‐mode ultrasound imaging by applying an echogenic surface coating. Our hypothesis was that an echogenic coating would reduce artifacts and improve needle visualization within regions of signal degradation.MethodsIn this study, 17‐gauge, 25‐cm long titanium HDR brachytherapy needles were coated with acoustically reflective microspheres over a 2.5 cm region starting from the needle tip. Three coating thicknesses (27 μm, 40 μm, 64 μm) were compared against an uncoated control needle. The coated and uncoated needles were imaged using B‐mode ultrasound in a tissue‐equivalent prostate phantom and in a cadaverous male pelvis using a transrectal probe. Needle conspicuity was assessed under multiple conditions: a single needle implant, an implant with multiple needles between the probe and the needle of interest, and an angled needle implant. All images were assessed qualitatively for needle conspicuity and the presence of artifacts and quantitatively using grey‐scale image intensity values.ResultsThe 64 μm echogenic coating reduced the magnitude of reverberation artifacts by 31 ± 14% and comet tail artifacts by 40%–70%. The echogenic coating also improved needle contrast, measured by the relative differences in signal intensity compared with the adjacent environment, when needles were angled up to 30° with respect to the transducer probe in the cadaver. The improvements in conspicuity and artifact reduction increased with increasing coating thickness. The performance of the needles coated with the 64 μm thickness was qualitatively superior and yielded high‐contrast, well‐circumscribed signals in the cadaverous male pelvis, even under situations where a needle was acoustically shadowed by multiple other needles.ConclusionsAn echogenic surface coating reduced imaging artifacts and improved needle conspicuity under realistic clinical conditions for ultrasound‐based prostate or gynecological brachytherapy. The improved conspicuity has the potential to improve the efficiency of needle placement and the accuracy of needle position digitization during brachytherapy procedures.