Faculty Bibliography

History A 54-year-old white woman with a history of rheumatoid arthritis who was taking glucocorticoids and methotrexate presented to the emergency department in December with worsening shortness of breath and chest heaviness for 1 week. She reported additional symptoms of weakness, headache, and arthralgia primarily involving her bilateral hands, wrist, ankles, and feet. She denied experiencing fevers, syncope or presyncope, focal neurologic deficits, chest pain, nausea, vomiting, unintentional weight loss, or recent trauma. Additional medical history included hypertension, asthma, degenerative disk disease, and migraine, all of which were reportedly controlled with medications. This patient had a smoking history of 80 pack-years, but she had quit smoking 2 months prior to presentation. She denied abuse of alcohol or recreational drugs and reported she was up-to-date on her immunizations, including those for pneumonia and flu. Family history was pertinent for breast cancer in her mother, sister, and maternal aunt. The patient reported normal findings at screening mammography and colonoscopy. A physical examination was remarkable for slightly asymmetric breath sounds, which appeared to be diminished on the right side. This patient had multiple joint deformities, most notably in the bilateral metacarpophalangeal joints. Initial electrocardiography findings and cardiac biomarkers were negative. Her complete blood count and basic metabolic profile were unremarkable. Posteroanterior and lateral chest radiographs were obtained in the emergency department. Subsequently, computed tomography (CT) of the chest was performed.

Introduction: To evaluate the accuracy of a quantitative 3D navigation system for CT-guided interventional procedures in a two-part study. Materials and Methods: Twenty-two procedures were performed in abdominal and thoracic phantoms. Accuracies of the 3D anatomy map registration and navigation were evaluated. Time used for the navigated procedures was recorded. In the IRB approved clinical evaluation, 21 patients scheduled for CT-guided thoracic and hepatic biopsy and ablations were recruited. CT-guided procedures were performed without following the 3D navigation display. Accuracy of navigation as well as workflow fitness of the system was evaluated. Results: In phantoms, the average 3D anatomy map registration error was 1.79 mm. The average navigated needle placement accuracy for one-pass and two-pass procedures, respectively, was 2.0 +/- 0.7 mm and 2.8 +/- 1.1 mm in the liver and 2.7 +/- 1.7 mm and 3.0 +/- 1.4 mm in the lung. The average accuracy of the 3D navigation system in human subjects was 4.6 mm +/- 3.1 for all procedures. The system fits the existing workflow of CT-guided interventions with minimum impact. Conclusion: A 3D navigation system can be performed along the existing workflow and has the potential to navigate precision needle placement in CT-guided interventional procedures.

Markov random field (MRF) model has been widely employed in edge-preserving regional noise smoothing penalty to reconstruct piece-wise smooth images in the presence of noise, such as in low-dose computed tomography (LdCT). While it preserves edge sharpness, its regional smoothing may sacrifice tissue image textures, which have been recognized as useful imaging biomarkers, and thus it may compromise clinical tasks such as differentiating malignant vs. benign lesions, e.g., lung nodules or colon polyps. This study aims to shift the edgepreserving regional noise smoothing paradigm to texturepreserving framework for LdCT image reconstruction while retaining the advantage of MRF's neighborhood system on edge preservation. Specifically, we adapted the MRF model to incorporate the image textures of muscle, fat, bone, lung, etc. from previous full-dose CT (FdCT) scan as a priori knowledge for texture-preserving Bayesian reconstruction of current LdCT images. To show the feasibility of the proposed reconstruction framework, experiments using clinical patient scans were conducted. The experimental outcomes showed a dramatic gain by the a priori knowledge for LdCT image reconstruction using the commonly-used Haralick texture measures. Thus, it is conjectured that the texture-preserving LdCT reconstruction has advantages over the edge-preserving regional smoothing paradigm for texture-specific clinical applications.

PURPOSE/OBJECTIVE:To evaluate the safety and efficacy of cryoneurolysis in patients with refractory peripheral neuropathic pain. MATERIALS AND METHODS/METHODS:Twenty-two patients referred for cryoneurolysis of refractory peripheral neuropathy were recruited prospectively from July 2011 to July 2013. The mean patient age was 49.5 years, and 41% of patients were female. Ultrasound imaging of the involved nerves was used for guidance. Percutaneous ablations were performed with a PerCryo 17R device. Pain levels were recorded on a visual analog scale (scores 0-10) before and at 1, 3, 6, 9, and 12 months after the procedure, and complications were documented. RESULTS:Mean pain levels were 8.3 ± 1.9 before intervention and 2.3 ± 2.5 at 1 month, 3.2 ± 2.5 at 3 months, 4.7 ± 2.7 at 6 months, and 5.1 ± 3.7 at 12 months afterward. A Wilcoxon rank-sum test was performed and showed a statically significant decrease between pre- and postprocedural pain scores. There were no complications from the procedures. DISCUSSION/CONCLUSIONS:Cryoneurolysis caused a significant decrease in self-reported pain scores in patients with chronic refractory neuropathic pain, with moderately long-term relief. Cryoneurolysis is an additional therapy that can alleviate severe chronic neuropathic pain.

Purpose: To assess the safety of percutaneous cryoablation for treatment of pulmonary metastases < 3.5 cm. Material and methods: Patients with up to 6 pulmonary metastases were treated in a multicenter, prospective study with CT-guided percutaneous cryoablation. Patient follow-up was performed at 1 week and 3, 6, 12, and 24 months. Complications were assessed using the CTCAE 4.03. Results: Two-hundred nineteen tumors in 126 patients (64 males, 62 females; mean age 64 years) were treated over 163 procedures, constituting the largest prospective multicenter lung cryoablation trial to date. Sixty-two percent (n=78) of the patients had 1 tumor, and 40% had 2 or more. Mean tumor size was 1.2 cm (0.4- 4.5 cm). General anesthesia was employed in 69% (n=113) of procedures, conscious sedation in 29% (n=47), and local anesthesia in 2% (n=3). Treatment time ranged from 30 to 225 min. (mean=72.9 min). Ninety-eight procedure-related events occurred within 30 days of the treatment. Thirty-seven percent were classified CTCAE grade 1 (n=36), 57% grade 2 (n=57), 5% grade 3 (n=5), and 1% grade 4 (n=1). The most frequent event was pneumothorax, of which 8% (n=4) were grade 1, 83% (n=40) grade 2, and 8% (n=4) grade 3. Six percent (n=6) of all events were grade 3 or higher: grade 3 pneumothoraces (n=4), grade 3 pleural hemorrhage (n=1), and grade 4 gas embolism (n=1). All events resolved without further sequelae. Conclusion: Percutaneous CT-guided cryoablation demonstrates an acceptable safety profile for treatment of lung metastases < 3.5 cm