Conventional Hepatic Volumetry May Lead to Inaccurate Segmental Yttrium-90 Radiation Dosimetry.

OBJECTIVE: To compare radioembolization treatment zone volumes from mapping cone beam CT (CBCT) versus planning CT/MRI and to model their impact on dosimetry. METHODS: Y90 cases were retrospectively identified in which intra-procedural CBCT angiograms were performed. Segmental and lobar treatment zone volumes were calculated with semi-automated contouring using Couinaud venous anatomy (planning CT/MRI) or tumor angiosome enhancement (CBCT). Differences were compared with a Wilcoxon signed-rank test. Treatment zone-specific differences in segmental volumes by volumetric method were also calculated and used to model differences in delivered dose using medical internal radiation dosimetry (MIRD) at 200 and 120 Gy targets. Anatomic, pathologic, and technical factors likely affecting segmental volumes by volumetric method were evaluated. RESULTS: Forty segmental and 48 lobar CBCT angiograms and corresponding planning CT/MRI scans were included. Median Couinaud- and CBCT-derived segmental volumes were 281 and 243 mL, respectively (p = 0.005). Differences between Couinaud and CBCT lobar volumes (right, left) were not significant (p = 0.24, p = 0.07). Couinaud overestimated segmental volumes in 28 cases by a median of 98 mL (83%) and underestimated in 12 cases by median 69 mL (20%). At a 200 Gy dose target, Couinaud estimates produced median delivered doses of 367 and 160 Gy in these 28 and 12 cases. At a 120 Gy target, Couinaud produced doses of 220 and 96 Gy. Proximal vs. distal microcatheter positioning, variant arterial anatomy, and tumor location on or near segmental watersheds were leading factors linked to volumetric differences. CONCLUSION: Use of CBCT-based volumetry may allow more accurate, personalized dosimetry for segmental Y90 radioembolization.

Celiac Plexus Block and Neurolysis in the Management of Chronic Upper Abdominal Pain.

Chronic upper abdominal pain occurs as a complication of various malignant and benign diseases including pancreatic cancer and chronic pancreatitis, and when present may contribute to lower quality of life and higher mortality. Though various pain management strategies are available as part of a multimodal approach, they are often incompletely effective and accompanied by side effects. Pain originating in upper abdominal viscera is transmitted through the celiac plexus, which is an autonomic plexus located in the retroperitoneum at the root of the celiac trunk. Direct intervention at the level of the plexus, referred to as celiac plexus block or neurolysis depending on the injectate, is a minimally invasive therapeutic strategy which has been demonstrated to decrease pain, improve function, and reduce opiate dependence. Various percutaneous techniques have been reported, but, with appropriate preprocedural planning, use of image guidance (usually computed tomography), and postprocedural care, the frequency and severity of complications is low and the success rate high regardless of approach. The main benefit of the intervention may be in reduced opiate dependence and opiate-associated side effects, which in turn improves quality of life. Celiac plexus block and neurolysis are safe and effective treatments for chronic upper abdominal pain and should be considered early in patients experiencing such symptoms.

Successful catheter-directed thrombolysis of a massive pulmonary embolism in a patient after recent pneumonectomy.

Massive pulmonary embolism (PE) after major thoracic surgery is an uncommon but life-threatening event that is challenging to manage. At present, the treatment of acute PE is either anticoagulation with or without systemic thrombolytic therapy. We report a case of a 65-year-old female with recent left pneumonectomy who developed a massive PE. The patient was successfully and safely treated with catheter-directed thrombolysis. To our knowledge, this is the first patient treated in this fashion.

Percutaneous ablation of peribiliary tumors with irreversible electroporation.

PURPOSE: To assess biliary complications after irreversible electroporation (IRE) ablation of hepatic tumors located < 1 cm from major bile ducts. MATERIALS AND METHODS: A retrospective review was conducted of all percutaneous IRE ablations of hepatic tumors within 1 cm of the common, left, or right hepatic ducts at a single institution from January 2011 to September 2012. Computed tomography imaging performed before and after treatment was examined for evidence of bile duct dilatation, stricture, or leakage. Serum bilirubin and alkaline phosphatase levels were analyzed for evidence of biliary injury. RESULTS: There were 22 hepatic metastases in 11 patients with at least one tumor within 1 cm of the common, left, or right hepatic duct that were treated with IRE ablations in 15 sessions. Median tumor size treated was 3.0 cm (mean, 2.8 cm ± 1.2, range, 1.0-4.7 cm). Laboratory values obtained after IRE were considered abnormal after four treatment sessions in three patients (bilirubin, 2.6-17.6 mg/dL; alkaline phosphatase, 130-1,035 U/L); these abnormal values were transient in two sessions. Two patients had prolonged elevation of values, and one required stent placement; both of these conditions appeared to be secondary to tumor progression rather than bile duct injury. CONCLUSIONS: This clinical experience suggests that IRE may be a treatment option for centrally located liver tumors with margins adjacent to major bile ducts where thermal ablation techniques are contraindicated. Further studies with extended follow-up periods are necessary to establish the safety profile of IRE in this setting.

CT angiography in the detection of carotid body enlargement in patients with hypertension and heart failure.

INTRODUCTION: The carotid body (CB) has previously been found to be enlarged and hyperactive in various disease states such as heart failure (HF), hypertension (HTN), and respiratory disease. Evaluation of CB size in these disease states using imaging has not been performed. The purpose of this case-control study was to compare CB sizes in patients with HF and HTN with those of controls using CT angiography. METHODS: A retrospective review was performed on 323 consecutive patients who had neck computed tomography angiography (CTA) exams in 2011. Following extensive review, 17 HF and HTN patients and 14 controls were identified. Two radiologists blinded to the patient disease status made consensus bilateral carotid body (CB) measurements on the CTA exams using a previously described standardized protocol. CB axial cross-sectional areas were compared between HF and HTN cases and controls using a paired t test. RESULTS: The right CB demonstrated a mean cross-sectional area of 2.79 mm(2) in HF and HTN patients vs. 1.40 mm(2) in controls (p = 0.02). The left CB demonstrated a mean cross-sectional area of 3.13 mm(2) in HF and HTN patients vs. 1.53 mm in controls (p = 0.03). CONCLUSION: Our results provide imaging evidence that the carotid bodies are enlarged in patients with HF and HTN. Our case-control series suggests that this enlargement can be detected on neck CTA.

Role of external beam radiotherapy in patients with advanced or recurrent nonanaplastic thyroid cancer: Memorial Sloan-kettering Cancer Center experience.

PURPOSE: External beam radiotherapy (EBRT) plays a controversial role in the management of nonanaplastic thyroid cancer. We reviewed our institution's outcomes in patients treated with EBRT for advanced or recurrent nonanaplastic thyroid cancer. METHODS AND MATERIALS: Between April 1989 and April 2006, 76 patients with nonanaplastic thyroid cancer were treated with EBRT. The median follow-up for the surviving patients was 35.3 months (range, 4.2-178.4). The lesions were primarily advanced and included Stage T2 in 5 (7%), T3 in 5 (7%), and T4 in 64 (84%) patients. Stage N1 disease was present in 60 patients (79%). Distant metastases before EBRT were identified in 27 patients (36%). The median total EBRT dose delivered was 6,300 cGy. The histologic features examined included medullary in 12 patients (16%) and nonmedullary in 64 (84%). Of the 76 patients, 71 (93%) had undergone surgery before RT, and radioactive iodine treatment was used in 56 patients (74%). RESULTS: The 2- and 4-year overall locoregional control rate for all histologic types was 86% and 72%, respectively, and the 2- and 4-year overall survival rate for all patients was 74% and 55%, respectively. No significant differences were found in locoregional control, overall survival, or distant metastases-free survival for patients with complete resection, microscopic residual disease, or gross residual disease. Grade 3 acute mucositis and dysphagia occurred in 14 (18%) and 24 (32%) patients, respectively. Late adverse toxicity was notable for percutaneous endoscopic gastrostomy tube use in 4 patients (5%). CONCLUSION: The results of our study have shown that EBRT is effective for locoregional control of selected locally advanced or recurrent nonanaplastic thyroid malignancies, with acceptable acute toxicity.

Effects of age on muscle as measured by electrical impedance myography.

Electrical impedance myography (EIM) is a painless and non-invasive technique for the assessment of muscle which we apply here to the effects of normal aging. The paper presents a cross-sectional analysis of EIM data from the quadriceps and tibialis anterior of 100 healthy subjects (44 men, 56 women, ages 18-90 years). The principal EIM parameter, the spatially averaged phase theta(avg), shows a roughly quadratic reduction with increasing age, declining more steeply beyond 60 years. The correlation was stronger in men (quadriceps: r2 = 0.68 for men, 0.52 for women; tibialis anterior: r2 = 0.74 for men, 0.38 for women; p < 0.001 throughout). Additionally, four subjects (age greater than 75 years) were asked to return for repeat testing several years after their initial assessment. These longitudinal results qualitatively confirm the cross-sectional data, though with greater reductions in theta(avg) at high age. The findings of this study support the potential use of EIM as a simple and effort-independent test of muscle health in the elderly.

Assessing neuromuscular disease with multifrequency electrical impedance myography.

Electrical impedance myography (EIM) is a noninvasive technique for neuromuscular assessment in which low-intensity alternating current is applied to a muscle and the consequent surface voltage patterns are evaluated. Previous work using a single frequency of 50 kHZ has demonstrated quantitative correlation of EIM parameters with disease status. In this investigation we examined the use of multifrequency EIM, studying a prototypical neurogenic disease (amyotrophic lateral sclerosis, ALS) and myopathic disorder (inflammatory myopathy, IM). Eleven ALS patients, 7 IM patients, and 46 normal subjects participated in the study. Although disease-specific patterns were not identified such that IM could be differentiated from ALS, impedance vs. frequency patterns for diseased subjects differed substantially from those of the age-matched normal subjects, with the greatest alterations occurring in the most severe cases. Multifrequency EIM may be well-suited to serve as an easily applied technique to assess disease severity in a variety of neuromuscular conditions.

Electrical impedance myography: transitioning from human to animal studies.

OBJECTIVE: To determine the feasibility of performing electrical impedance myography (EIM) in rats. METHODS: EIM was performed on the hamstring muscles of 6 healthy adult rats with applied frequencies of 2-300 kHz. Studies were performed over a 6-week period, with 3 rats having recordings made from the skin (surface EIM) and 3 with recordings directly from the muscle (direct-muscle EIM). In addition, sciatic nerve crush was performed on one rat and comparisons made pre- and post-injury. Reactance and resistance were measured and the primary outcome variable, the phase angle (theta), calculated. RESULTS: EIM patterns in the rat hamstring muscles were qualitatively similar to those observed in human subjects. This held true for both surface and direct-muscle recordings, although direct-muscle data appeared less repeatable. Sciatic nerve crush data in the single rat showed a dramatic reduction in phase and a relative loss of frequency-dependence. CONCLUSIONS: EIM data similar to that obtained from human subjects can be acquired from rat muscles with surface recordings proving more consistent and easier to obtain than direct-muscle recordings. Changes seen with sciatic nerve crush mirror those seen in patients with neurogenic injury. SIGNIFICANCE: These results support the possibility of performing EIM on rat models of neuromuscular disease.

Test-retest reproducibility of 50 kHz linear-electrical impedance myography.

OBJECTIVE: Electrical impedance myography (EIM) is a method for evaluating muscle in which high-frequency, low-intensity alternating current is applied to a body region and the resulting surface voltage pattern over a muscle of interest is measured. In this study, the reproducibility for the simplest of these techniques, 50 kHz linear-EIM, was assessed for three muscles. METHODS: Fifty kilohertz linear-EIM was performed on the biceps, quadriceps, and tibialis anterior of 30 normal subjects ranging in age from 21 to 90 years, and the major outcome variable, the spatially averaged phase (thetaavg), measured. The measurements were repeated within 250 days and comparisons between the two data sets made. RESULTS: Reproducibility, as measured by the intraclass correlation coefficients for all three muscles, was very high at 0.970, 0.971, and 0.938 for biceps, quadriceps, and tibialis anterior, respectively. Variability between measurements was on average 4.2% for all muscle combined, with an upper limit of 16.8%. CONCLUSIONS: Fifty kilohertz linear-EIM demonstrates excellent test-retest reproducibility. SIGNIFICANCE: These results support the view that 50 kHz linear-EIM has the potential to be used as a simple, fast, and non-invasive measurement for the assessment of disease status, either as part of individual patient care or as a surrogate outcome measure in clinical trials work.

Electrical impedance myography in the detection of radiculopathy.

Electrical impedance myography (EIM) is a new bioimpedance-based technique for neuromuscular disease assessment. Past work has focused on EIM in the evaluation of diffuse diseases (such as myopathy). In this study, the method's most basic form, linear-EIM, was used for the assessment of restricted radiculopathic disease. Ten normal subjects and 10 patients with unilateral cervical or lumbosacral radiculopathy, diagnosed by electromyography and clinical criteria, were enrolled. Linear-EIM was performed bilaterally on all individuals, and comparisons with the major outcome variable, theta(avg), were made. In normal subjects, side-to-side differences in theta(avg) averaged 0.64% and were no greater than 15.9% in magnitude. In the 10 patients with radiculopathy, theta(avg)was consistently lower in the affected extremity, with a mean side-to-side difference of 15.3%, but ranging as low as 72.3%; there was a tendency for muscles with more prominent chronic neurogenic change to show greater relative reductions in theta(avg). These findings support the potential utility of EIM in assessment of localized neuromuscular disease.