PURPOSE
To assess the feasibility of percutaneous multiprobe breast
cryoablation (BC) for diverse presentations of cancers that remained in situ
after BC.
MATERIALS AND METHODS
After breast magnetic resonance (MR) imaging and thorough
consultation, patients underwent BC after giving informed consent. This
study was approved by the institutional review board. In 12 BC sessions, 22
breast cancer foci (stages I–IV) were treated in 11 patients who
refused surgery by using multiple 2.4-mm cryoprobes. Five patients had
recurrent disease and six had new diagnoses. With use of only local
anesthesia, six patients were treated with ultrasonographic (US) guidance
and five were treated with both computed tomographic (CT) and US guidance.
Saline injections and warming bags were used to protect the skin. Procedure
success was defined as 1 cm visible ice beyond all tumor margins. MR imaging
and/or clinical follow-up were available for up to 72 months after BC.
RESULTS
US produced sufficient ice visualization for small tumors, whereas CT
helped confirm overall ice extent. The mean pretreatment breast tumor
diameter was 1.7 cm ± 1.2 (range, 0.5–5.8 cm), and an
average of 3.1 cryoprobes produced 100% procedural success with mean
ice diameters of 5.1 cm ± 2.2 (range, 2.0–10.0 cm). No
significant complications, retraction, or scarring were noted. Biopsies at
the margins of the cryoablation site immediately after BC and at follow-up
were all negative. No local recurrences have been noted at an average
imaging follow-up of 18 months.
CONCLUSIONS
In conjunction with thorough pre- and postablation MR imaging,
CT/US-guided multiprobe BC safely achieved 1 cm visible ice beyond tumor
margins with minimal discomfort, good cosmesis, and no short-term local
tumor recurrences.
Objective
To determine the clinical display thresholds of an ultrasound tomography (UST) prototype relative to magnetic resonance (MR) for comparable visualization of breast anatomy and tumor rendering.
Materials and Methods
The study was compliant with HIPAA, approved by the IRB, and performed after obtaining informed consent. Thirty-six women were imaged with MR and our UST prototype. The UST scan generated reflection, sound speed and attenuation images. The reflection images were fused with the components of sound speed and attenuation images that achieved thresholds to represent parenchyma and/or solid masses using an image arithmetic process. Qualitative and quantitative comparisons of MR and UST clinical images were used to identify anatomical similarities, and optimized thresholds for tumor shapes and volumes.
Results
Thresholding techniques generated UST images comparable to MR for visualizing fibrous stroma, parenchyma, fatty tissues, and tumors, of which 25 were cancer and 11 benign. Optimized sound speed thresholds of 1.46±0.1 km/s and 1.52±0.03 km/s were identified to best represent the extent of fibroglandular tissue and solid masses, respectively. An arithmetic combination of attenuation images using the threshold of 0.16±0.04 dB/cm further characterized benign from malignant masses. No significant difference in tumor volume was noted between benign or malignant masses by UST or MR (p>0.1) using these universal thresholds.
Conclusion
UST demonstrated the ability to image and render breast tissues in a manner comparable to MR. Universal UST threshold values appear feasible for rendering of the size and distribution of benign and malignant tissues without intravenous contrast.
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