Bradley D. Lewis

Treatment of Neuroendocrine Cancer Metastatic to the Liver: The Role of Ablative Techniques

Carcinoid tumors and islet cell neoplasms are neuroendocrine neoplasms with indolent patterns of growth and association with bizarre hormone syndromes. These tumors behave in a relatively protracted and predictable manner, which allows for multiple therapeutic options. Even in the presence of hepatic metastases, the standard of treatment for neuroendocrine malignancy is surgery, either with curative intent or for tumor cytoreduction, i.e., resection of 90% or more of the tumor volume. Image-guided ablation, as either an adjunct to surgery or a primary treatment modality, can be used to treat neuroendocrine cancer metastatic to the liver. Image-guided ablative techniques, including radiofrequency ablation, alcohol injection, and cryoablation, can be used in selected patients to debulk hepatic tumors and improve patient symptoms. Although long-term follow-up data are not available, the surgical literature indicates that significant ablative debulking may improve patient survival. In this review, we discuss metastatic neuroendocrine disease and its treatment options, especially image-guided ablative techniques.

Current Applications of Duplex and Color Doppler Ultrasound Imaging: Abdomen

Duplex ultrasound studies and color Doppler imaging have substantially enhanced the diagnostic capabilities of abdominal ultrasonography. The status of the flow in the major abdominal vessels is routinely obtainable along with anatomic information about the organs that they supply. The current applications of duplex and color Doppler imaging in evaluating the hepatic vascular system, hepatic transplants, aorta, splanchnic arterial system, renal artery and vein, renal transplants, and penile arterial system are reviewed. The indications for and limitations of these examinations, as well as the potential future uses, are discussed.

Current Applications of Duplex and Color Doppler Ultrasound Imaging: Carotid and Peripheral Vascular System

Recent advances in ultrasound technology have made possible the development of diagnostic instruments that combine cross-sectional imaging and Doppler analysis. These instruments have expanded the role of diagnostic ultrasonography to the assessment of carotid and peripheral vascular disease. The current applications of duplex Doppler and color Doppler imaging in evaluating the extracranial carotid arteries, vertebral artery, peripheral venous system, and peripheral arterial system are reviewed. The indications for and limitations of these examinations, as well as the potential future uses, are discussed.

Radiofrequency Treatment of Hepatic Neoplasms in Patients With Permanent Pacemakers

Clinicians who provide care for patients with implantable devices for rhythm management, ie, pacemakers and internal cardioverter defibrillators, must be aware of sources of interference that could affect device function. Intracardiac radiofrequency is a recognized source of potential interference. However, radiofrequency to extracardiac sites that are relatively close to the implanted device has not been investigated thoroughly. We present 2 patients with permanent pacemakers undergoing intrahepatic radiofrequency for the treatment of metastatic disease. No interference was documented in either patient. Additional in vitro and in vivo studies are needed to determine definite clinical guidelines for such patients.

Ultrasound appearance of synovial osteochondromatosis of the shoulder

This case report demonstrates the ultrasound appearance of synovial osteochondromatosis of the shoulder, along with plain film radiographic, computed tomographic, and pathologic correlation. Because of recent renewed interest in the use of ultrasonography in the evaluation of musculoskeletal disease, such as rotator cuff arthropathy or suspected intra-articular loose body, opportunities to diagnose synovial osteochondromatosis with this modality have become more frequent.

Reliability of water proton chemical shift temperature calibration for focused ultrasound ablation therapy.

Our purpose in this work was to assess the reliability of the calibration coefficient for magnetic resonance water proton chemical shift temperature mapping. Over a six month period, the calibration coefficient was measured 15 times in several different phantoms. A highly linear relationship between water proton chemical shift and temperature change was found. The average temperature calibration coefficient determined from all studies was 0.009+/-0.001 ppm/degrees C. Four of the 15 studies were conducted on the same day using the same phantom. The average temperature calibration coefficient of these four studies was 0.0096+/-0.0001 ppm/degrees C.

Nonleg Venous Thrombosis in Critically Ill Adults: A Nested Prospective Cohort Study

IMPORTANCE Critically ill patients are at risk of venous thrombosis, and therefore guidelines recommend daily thromboprophylaxis. Deep vein thrombosis (DVT) commonly occurs in the lower extremities but can occur in other sites including the head and neck, trunk, and upper extremities. The risk of nonleg deep venous thromboses (NLDVTs), predisposing factors, and the association between NLDVTs and pulmonary embolism (PE) or death are unclear. OBJECTIVE To describe the frequency, anatomical location, risk factors, management, and consequences of NLDVTs in a large cohort of medical-surgical critically ill adults. DESIGN, SETTING, AND PARTICIPANTS A nested prospective cohort study in the setting of secondary and tertiary care intensive care units (ICUs). The study population comprised 3746 patients, who were expected to remain in the ICU for at least 3 days and were enrolled in a randomized clinical trial of dalteparin vs standard heparin for thromboprophylaxis. MAIN OUTCOMES AND MEASURES The proportion of patients who had NLDVTs, the mean number per patient, and the anatomical location. We characterized NLDVTs as prevalent or incident (identified within 72 hours of ICU admission or thereafter) and whether they were catheter related or not. We used multivariable regression models to evaluate risk factors for NLDVT and to examine subsequent anticoagulant therapy, associated PE, and death. RESULTS Of 3746 trial patients, 84 (2.2%) developed 1 or more non-leg vein thromboses (superficial or deep, proximal or distal). Thromboses were more commonly incident (n = 75 [2.0%]) than prevalent (n = 9 [0.2%]) (P < .001) and more often deep (n = 67 [1.8%]) than superficial (n = 31 [0.8%]) (P < .001). Cancer was the only independent predictor of incident NLDVT (hazard ratio [HR], 2.22; 95% CI, 1.06-4.65). After adjusting for Acute Physiology and Chronic Health Evaluation (APACHE) II scores, personal or family history of venous thromboembolism, body mass index, vasopressor use, type of thromboprophylaxis, and presence of leg DVT, NLDVTs were associated with an increased risk of PE (HR, 11.83; 95% CI, 4.80-29.18). Nonleg DVTs were not associated with ICU mortality (HR, 1.09; 95% CI, 0.62-1.92) in a model adjusting for age, APACHE II, vasopressor use, mechanical ventilation, renal replacement therapy, and platelet count below 50 × 10(9)/L. CONCLUSIONS AND RELEVANCE Despite universal heparin thromboprophylaxis, nonleg thromboses are found in 2.2% of medical-surgical critically ill patients, primarily in deep veins and proximal veins. Patients who have a malignant condition may have a significantly higher risk of developing NLDVT, and patients with NLDVT, compared with those without, appeared to be at higher risk of PE but not higher risk of death. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT00182143.

Radiation Dose Reduction for CT-Guided Renal Tumor Cryoablation

OBJECTIVE The purpose of this article is to retrospectively determine the image quality and degree of radiation dose reduction that is clinically acceptable for CT-guided renal tumor cryoablation. MATERIALS AND METHODS A total of 15 patients (17 procedures; mean age, 67 years; range, 38-85 years) undergoing clinically indicated CT-guided renal tumor cryoablation procedures were included in this retrospective study. A previously validated noise-insertion tool was used to simulate reduced-dose scans at 75%, 50%, 25%, and 10% of the original dose at four representative phases of the cryoablation procedure. Images obtained at different dose levels were randomized and reviewed by three radiologists blinded to the level of dose reduction, who scored them independently with a 5-point scale (1-5, with 5 the best). Images with a mean score of 3 or higher were considered diagnostically acceptable. The minimal acceptable dose was that at which 90% of images were considered diagnostically acceptable. Interrater agreement was assessed using the weighted kappa statistic. RESULTS The weighted kappa value was 0.68, indicating substantial agreement among the reviewers. The averaged percentage of diagnostically acceptable images for the four series was 100% for a full dose, 98-100% for the 75% dose level, 94-98% for the 50% dose level, and less than 90% for images obtained at the 25% and 10% dose levels, which was considered unacceptable. CONCLUSION On the basis of results from 15 patients (17 procedures), images obtained from CT acquisitions at 50% (volume CT dose index, 12.2 mGy) of the original dose level (volume CT dose index, 24.4 mGy) were acceptable for the purpose of CT monitoring of renal cryoablation procedures.

Carotid Doppler Ultrasound Findings in Patients With Left Ventricular Assist Devices

Left ventricular assist devices (LVADs) have been used to treat advanced heart failure refractory to medical management, as bridge therapy to myocardial recovery, as bridge therapy to cardiac transplantation, or as destination therapy for patients with unfavorable transplant candidacy. Neurologic complications are some of the most common and devastating complications in these patients. Preoperative carotid ultrasound is, therefore, a standard evaluation in patients at risk for cerebrovascular disease. Postoperative carotid artery Doppler sonography is performed in those patients with neurologic symptoms. It is likely, therefore, that sonographers, radiologists, and other physicians working in a center where LVADs are implanted will likely encounter a carotid artery Doppler study in this patient group. To our knowledge, the carotid Doppler findings in these patients have never been published. We review the Doppler ultrasound findings in 6 patients after LVAD insertion.

Ultrasound-guided biopsy and ablation in the neck.

Management and therapy of conditions of the thyroid, parathyroid glands, and cervical lymph nodes have evolved rapidly during the past 15 years. The development and continued improvement of high-resolution ultrasound (US) equipment, US-guided biopsy, and image-guided ablative techniques have fueled this change. These technical improvements and the knowledge and experience gained during this time have decreased the rate of unnecessary surgery in patients with thyroid nodules. They have also allowed more limited neck dissection in patients with parathyroid adenomas and have led to the development of US-guided ablative techniques that have eliminated the need for surgery in some cases. This article reviews the rationale and techniques of US-guided biopsy of the thyroid, parathyroid, and cervical lymph nodes. Established and evolving ablative techniques of these structures are also examined.