A target definition based on electroanatomic maps for stereotactic arrhythmia radioablation.

PURPOSE: Identifying the target region is critical for successfully treating ventricular tachycardia (VT) with single fraction stereotactic arrhythmia radioablation (STAR). We report the feasibility of target definition based on direct co-registration of electroanatomic maps (EAM) and radioablation planning images. MATERIALS AND METHODS: The EAM consists of 3D cardiac anatomy representation with electrical activity at endocardium and is acquired by a cardiac electrophysiologist (CEP) during electrophysiology study. The CEP generates an EAM using a 3D cardiac mapping system anticipating radioablation planning. Our in-house software read these non-DICOM EAMs, registered them to a planning image set, and converted them to DICOM structure files. The EAM based target volume was finalized based on a consensus of CEPs, radiation oncologists and medical physicists, then expanded to ITV and PTV. The simulation, planning, and treatment is performed with a standard STAR technique: a single fraction of 25 Gy using volumetric-modulated arc therapy or dynamic conformal arc therapy depending on the target shape. RESULTS: Seven patients with refractory VT were treated by defining the target based on registering EAMs on the planning images. Dice similarity indices between reference map and reference contours after registration were 0.814 ± 0.053 and 0.575 ± 0.199 for LV and LA/RV, respectively. CONCLUSIONS: The quality of the transferred EAMs on the MR/CT images was sufficient to localize the treatment region. Five of 7 patients demonstrated a dramatic reduction in VT events after 6 weeks. Longer follow-up is required to determine the true safety and efficacy of this therapy using EAM-based direct registration method.

Case of a 57-Year-Old Man With Malignant Mesothelioma Presenting With Miliary Nodules on Chest Imaging.

CASE PRESENTATION: A 57-year-old man with history of stage IIIB right-sided malignant pleural mesothelioma was admitted from his oncologist's office for progressive dyspnea of two weeks duration. He had associated dyspnea at rest and a new dry cough. He denied sputum production, hemoptysis, or fevers, but he did endorse chills, fatigue, and weight loss. The patient was a veteran of the Navy and had extensive international travel in his 20s. He had never been incarcerated and denied any sick contacts or recent travels. He had received a diagnosis of mesothelioma 11 months earlier after presenting to his physician's office with complaints of shortness of breath on exertion. Initial imaging revealed a large right-sided pleural effusion with irregular pleural thickening. He underwent right-sided thoracoscopy, and the pleural biopsy result was consistent with epithelioid mesothelioma. Because of invasion of his seventh rib, he was not a candidate for surgery and underwent palliative radiation and chemotherapy with cisplatin, pemetrexed, and bevacizumab. He was undergoing his eighth cycle of chemotherapy at the time of presentation.

Morgagni Hernia Causing Incarcerated Bowel and Contributing to Cardiac Arrest.

A Morgagni hernia is a congenital diaphragmatic hernia (CDH)-incomplete formation of the diaphragm. Though congenital diaphragmatic hernias (CDHs) are a common class of birth defect, the majority are diagnosed either prenatally or shortly after birth since these patients can present with cardiopulmonary failure due to pulmonary hypoplasia or pulmonary hypertension.1 However, the Morgagni type of CDH predisposes it to go undetected well into adulthood. We describe the case of a 63-year-old male who presented to the emergency room with epigastric pain and emesis. He was found to have incarcerated bowel in his pericardial sac on computed tomography imaging after being resuscitated from cardiac arrest. He then underwent surgical repair of the defect. This case is unique in its presentation with small bowel inside the pericardium, contributing to cardiac tamponade and subsequent cardiac arrest.

Image-based management of empiric lung stereotactic body radiotherapy (SBRT) without biopsy: Predictors from a 10-year single institution experience.

BACKGROUND: There is emerging reliance on clinical imaging for the diagnosis, prognosis, and treatment evaluation of early stage non-small cell lung cancer (NSCLC) in patients deemed too high risk for biopsy. We report our experience of clinically diagnosed NSCLC treated empirically with stereotactic body radiotherapy (SBRT) to validate the imaging parameters used for management in this high-risk population. METHODS: We reviewed 101 empiric lung SBRT cases and profiled imaging specifics of computed tomography and positron emission tomography for diagnosis and follow-up. Secondarily, we identified potential correlates of disease progression with Cox regression multivariate analysis. RESULTS: Fifty-seven men and 43 women aged 45-94 (median 76) were treated with a median dose of 48 Gy in four fractions. The median nodule diameter was 1.6 cm (0.6-4.5 cm) and most were spiculated (n = 58), right-sided (n = 63), and in the upper lobe (n = 68). Median follow-up and survival rates were 14 and 28 months, respectively. Local control at three years was 94%. Freedom from any progression at one and three years was 85% and 69%, respectively. Toxicity ≥ grade 3 included two grade 3 dyspneas. A pre-treatment standard uptake value > 4.1 was the only significant predictor of disease progression. CONCLUSION: This study illustrates the instrumental role of modern clinical imaging for the effective management of presumed early stage NSCLC treated with empiric lung SBRT. As lung SBRT without tissue confirmation becomes more common, hopefully these assertions can be prospectively validated.

Pulmonary epithelioid angiosarcoma responsive to chemotherapy: A case report.

Primary pulmonary epithelioid angiosarcoma (AS) is an extremely rare cancer with a poor prognosis. The presenting symptoms and imaging results are nonspecific and hold similarities with more common lung pathology, contributing to missed or delayed diagnosis. Complementing radiological imaging with patient information, such as presenting symptoms and exposures, is important for early consideration of pulmonary epithelioid AS. Even with supportive imaging findings and clinical suspicion for pulmonary epithelioid AS, the most reliable and definitive method for diagnosis is through immunohistochemistry. We describe the case of a 65-year-old patient who presented with dyspnea, cough, and hemoptysis in whom pauci-immune vasculitis was initially suspected before immunohistochemical diagnosis of primary pulmonary epithelioid AS. Due to the rarity of this disease, treatment options have not been well-studied and consist of any combination of surgical resection, chemotherapy, and radiation therapy. Although typically poorly responsive to chemotherapy, our patient achieved a reduction in size of his pulmonary nodules after a course of steroids followed by cyclophosphamide and was later maintained with gemcitabine and docetaxel until his death nearly a year after presentation.

CT of viral lower respiratory tract infections in adults: comparison among viral organisms and between viral and bacterial infections.

OBJECTIVE: We retrospectively compared the CT findings of consecutive viral and bacterial lower respiratory tract infections (LRTIs) to determine their imaging appearance and any definable differences among the causative viruses and between the viral and bacterial infections. MATERIALS AND METHODS: Imaging features of LRTI caused by influenza virus, respiratory syncytial virus (RSV), parainfluenza, adenovirus, and bacteria over a 33-month period were reviewed by three radiologists blinded to clinical and diagnostic information. Individual CT features and the dominant pattern of infection were recorded for each examination. Imaging characteristics were compared among the four respiratory viruses and between viral and bacterial infections. RESULTS: One hundred fifteen chest CT scans were analyzed (60 influenza virus, 19 RSV, 10 adenovirus, four parainfluenza virus, and 22 bacterial pneumonia LRTIs). Individual imaging findings and imaging patterns were seen in similar frequencies when we compared viral and bacterial LRTIs, with the exception of the diffuse airspace pattern, which was seen more frequently in bacterial infections. Although there was overlap in the imaging appearance of individual viruses, RSV and adenovirus tended to have characteristic imaging appearances. RSV presented with an airway-centric pattern of disease (13/19 cases [68%]) characterized by varying mixtures of tree-in-bud opacities and bronchial wall thickening, with or without peribronchiolar consolidation. Adenovirus typically appeared as multifocal consolidation or ground-glass opacity without airway inflammatory findings (7/10 cases [70%]). CONCLUSION: There is considerable overlap in the imaging appearance of viral and bacterial respiratory infections. However, some characteristic differences can be seen, especially with RSV and adenovirus infections.

Chest computed tomographic imaging characteristics of viral acute lower respiratory tract illnesses: a case-control study.

OBJECTIVE: This study aimed to determine whether computed tomographic (CT) findings can distinguish viral lower respiratory tract illness (LRTI) from other conditions. METHODS: Three radiologists reviewed CT images of patients with LRTI who underwent testing for respiratory viral infection. Imaging findings in subjects with positive viral assays were compared with subjects with negative assays. RESULTS: Of 334 subjects, 93 were positive for viral LRTI. Tree-in-bud opacities and bronchial wall thickening were observed more often in subjects with viral LRTI (P < 0.05). Multifocal airspace disease occurred with similar frequency in both groups. Diffuse airspace opacification was negatively associated with viral LRTI. Pleural effusion was observed more often among subjects without viral LRTI (P < 0.001). CONCLUSIONS: Airway inflammatory changes such as tree-in-bud opacities, bronchial wall thickening, and peribronchiolar consolidation are associated with community-acquired viral LRTI. Recognition of these findings should prompt testing for viral infection. Multifocal consolidation is commonly found in cases of viral LRTI but is nonspecific.

Differences in the epidemiological characteristics and clinical outcomes of pandemic (H1N1) 2009 influenza, compared with seasonal influenza.

BACKGROUND: There are limited data comparing the clinical presentations, comorbidities, and outcomes of patients with infections due to seasonal influenza with patients with infections due to pandemic (H1N1) 2009 influenza. OBJECTIVE: To compare the epidemiological characteristics and outcomes of pandemic (H1N1) 2009 influenza with those of seasonal influenza. METHODS: A cross-sectional study was conducted among patients who received diagnoses during emergency department and inpatient encounters at 2 affiliated academic medical centers in Philadelphia, Pennsylvania. Cases of seasonal influenza during the period November 1, 2005, through June 1, 2008, and cases of pandemic influenza during the period from May 1, 2009, through August 7, 2009, were identified retrospectively. RESULTS: Forty-nine cases of pandemic influenza and 503 cases of seasonal influenza were identified. Patients with pandemic H1N1 were younger (median age, 29 years) than patients with seasonal influenza (median age, 59 years) (P<.001). More patients with pandemic H1N1 (35 [71%] of 49) were African American, compared with patients with seasonal influenza (267 [53%] of 503; P=.02). Several symptoms were more common among patients with pandemic influenza infections than among patients with seasonal influenza infections: cough (98% vs 83%; P=.007), myalgias (71% vs 46%; P=.001), and pleuritic chest pain (45% vs 15%; P<.001). Pregnancy was the only comorbidity that occurred significantly more often in the pandemic influenza group than in the seasonal influenza group (16% vs 1%; P<.001). There were no significant differences in frequencies of deaths of hospitalized patients, intensive care unit admission, or length of hospitalization between groups. CONCLUSION: Other than pregnancy, there were few clinically important differences between infections due to seasonal influenza and those due to pandemic influenza. The greater rate of lower respiratory tract symptoms in pandemic cases might serve to differentiate pandemic influenza from seasonal influenza.

An uncommon cause of Ortner syndrome.

Ortner syndrome is a rare cause of hoarseness, resulting from compression of the left recurrent laryngeal nerve by a cardiovascular etiology. It was initially described secondary to left atrial enlargement and mitral valve disease. Other causes have now been recently described. We present a case of Ortner syndrome caused by penetrating atherosclerotic ulcers of the thoracic aorta.

Factors mediating powerful voltage attenuation along CA1 pyramidal neuron dendrites.

We performed simultaneous patch-electrode recordings from the soma and apical dendrite of CA1 pyramidal neurons in hippocampal slices, in order to determine the degree of voltage attenuation along CA1 dendrites. Fifty per cent attenuation of steady-state somatic voltage changes occurred at a distance of 238 microm from the soma in control and 409 microm after blocking the hyperpolarization-activated (H) conductance. The morphology of three neurons was reconstructed and used to generate computer models, which were adjusted to fit the somatic and dendritic voltage responses. These models identify several factors contributing to the voltage attenuation along CA1 dendrites, including high axial cytoplasmic resistivity, low membrane resistivity, and large H conductance. In most cells the resting membrane conductances, including the H conductances, were larger in the dendrites than the soma. Simulations suggest that synaptic potentials attenuate enormously as they propagate from the dendrite to the soma, with greater than 100-fold attenuation for synapses on many small, distal dendrites. A prediction of this powerful EPSP attenuation is that distal synaptic inputs are likely only to be effective in the presence of conductance scaling, dendritic excitability, or both.