Jared D. Christensen

Utility of FDG PET/CT in Inflammatory Cardiovascular Disease

Inflammatory disorders of the cardiovascular system can affect the myocardium, pericardium, or vessel walls. Patients with myocardial and pericardial disease may present with chest pain, palpitations, and shortness of breath, symptoms resembling myocardial ischemia or infarction. The manifestations of vasculitis may include fever, weight loss, and fatigue, mimicking infectious or malignant processes. Because of the difficulty of differentiating these disease processes, patients frequently undergo multiple diagnostic examinations before obtaining a final diagnosis of myocarditis, pericarditis, or vasculitis. Computed tomography (CT) and magnetic resonance imaging play important roles in the assessment of structural abnormalities of the cardiovascular system, and combined positron emission tomography (PET) and CT may depict inflammatory processes before structural changes occur. Familiarity with the PET/CT appearances of inflammatory processes in the myocardium, pericardium, and vessels is important for accurate and prompt diagnosis.

Real-time sonoelastography of hepatic thermal lesions in a swine model

Sonoelastography has been developed as an ultrasound-based elasticity imaging technique. In this technique, external vibration is induced into the target tissue. In general, tissue stiffness is inversely proportional to the amplitude of tissue vibration. Imaging tissue vibration will provide the elasticity distribution in the target region. This study investigated the feasibility of using real-time sonoelastography to detect and estimate the volume of thermal lesions in porcine livers in vivo. A total of 32 thermal lesions with volumes ranging from 0.2to5.3cm3 were created using radiofrequency ablation (RFA) or high-intensity focused ultrasound (HIFU) technique. Lesions were imaged using sonoelastography and coregistered B-mode ultrasound. Volumes were reconstructed from a sequence of two-dimensional scans. The comparison of sonoelastographic measurements and pathology findings showed good correlation with respect to the area of the lesions (r2=0.8823 for RFA lesions, r2=0.9543 for HIFU lesions). In addition, good correspondence was found between three-dimensional sonoelastography and gross pathology (3.6% underestimate), demonstrating the feasibility of sonoelastography for volume estimation of thermal lesions. These results support that sonoelastography outperforms conventional B-mode ultrasound and could potentially be used for assessment of thermal therapies.

Ascending Thoracic Aorta: Postoperative Imaging Evaluation

Advances in computed tomography (CT) scanners and electrocardiographic gating techniques have resulted in superior image quality of the ascending aorta and increased the use of CT angiography for evaluating the postoperative ascending aorta. Several abnormalities of the ascending aorta and aortic arch often require surgery, and various open techniques may be used to reconstruct the aorta, such as the Wheat procedure, in which both an ascending aortic graft and an aortic valve prosthesis are implanted; the Cabrol and modified Bentall procedures, in which a composite synthetic ascending aorta and aortic valve graft are placed; the Ross procedure, in which the aortic valve and aortic root are replaced with the patients native pulmonary valve and proximal pulmonary artery; valve-sparing procedures such as the T. David-V technique, which leaves the native aortic valve intact; and more extensive arch repair procedures such as the elephant trunk and arch-first techniques, in which interposition or inclusion grafts are implanted, with or without replacement of the aortic valve. Normal postoperative imaging findings, such as hyperattenuating felt pledgets, prosthetic conduits, and reanastomosis sites, may mimic pathologic processes. Postoperative complications seen at CT angiography that require further intervention include pseudoaneurysms, anastomotic stenoses, dissections, and aneurysms. Radiologists must be familiar with these procedures and their imaging features to identify normal postoperative appearances and complications.

Correlation of [18F]-2-fluoro-deoxy-D-glucose positron emission tomography standard uptake values with the cellular composition of stage I nonsmall cell lung cancer

The aim of the current study was to determine whether the [18F]‐2‐fluoro‐deoxy‐D‐glucose (FDG) positron emission tomography (PET) standardized uptake value (SUV) in patients with a new diagnosis of stage I lung cancer correlates with a specific cellular component in the primary tumor.

Interactions between propofol and lipid mediator receptors : Inhibition of lysophosphatidate signaling

As a highly lipophilic drug, propofol may interact with lipophilic domains in addition to its likely primary site of action on the gamma-aminobutyrateA (GABAA) receptor. likely candidates for such interaction are the G protein-coupled membrane receptors for lipid intercellular mediators. The phospholipid lysophosphatidate (LP) has attracted attention as such a signaling molecule. It has a variety of biological actions, including vasoconstriction. We therefore studied the interaction between propofol and the LP receptor. Intracellular Ca2+ release in response to LP was assessed by measuring Cl- flux through Ca2+ -activated Cl- channels in Xenopus oocytes. The average charge movement in response to LP 10-7 M was 2.0 +/- 0.2 microCoulombs. Propofol in Intralipid[R] (0.01%) dose-dependently inhibited LP signaling (50% inhibitory concentration [IC50] 5.38 micro M). Propofol 28 micro M inhibited LP signaling by 81%. Intralipid[R] (0.01%) was without effect. To ascertain that intracellular signaling pathways and the Ca2+ -activated Cl (-) channel were not affected by propofol, we tested the effects of propofol (5.6 micro M) on currents induced by methylcholine (10-7 M) in oocytes expressing the m1 muscarinic acetylcholine receptor. No inhibition was observed. As both receptors share the same intracellular signaling pathway, we conclude that clinically relevant concentrations of propofol most likely inhibit the LP receptor or its G protein. Inhibition of LP signaling may explain some of propofols vasodilating actions. (Anesth Analg 1996;83:1090-6)

Effects of Iopamidol-370 Versus Iodixanol-320 on Coronary Contrast, Branch Depiction, and Heart Rate Variability in Dual-Source Coronary MDCT Angiography

OBJECTIVE The purpose of this article is to assess whether iopamidol-370 provides superior vascular contrast of the coronaries and depiction of anatomic detail without affecting heart rate and beat-to-beat variability during coronary dual-source MDCT compared with iodixanol-320. SUBJECTS AND METHODS In this prospective trial, coronary CT angiography was performed on 60 adult patients using either iopamidol-370 or iodixanol-320. Cohorts were matched by age, habitus, sex, and baseline heart rate, with cohort sizes determined by power analysis. All studies were performed on a dual-source MDCT scanner with retrospective ECG-gating utilizing automatic pitch adjustment. Data assessment focused on heart rate variability during contrast administration statistically evaluated as Student t test comparisons within and between cohorts, coronary contrast-to-noise ratio analysis of the main coronary arteries utilizing Student t test comparisons between cohorts, and coronary branch depiction and distribution analysis in dual-reader consensus decisions between cohorts. RESULTS Thirty patients matched for age, habitus, sex, and heart rate were evaluated in each cohort. ECG analyses found a statistically significant (p = 0.013) decrease in heart rate during administration of iodixanol-320. Beat-to-beat variations, expressed as coefficient of variation, within and among cohorts were low (coefficient of variation, < 0.05). Contrast-to-noise ratio was significantly increased for iopamidol-370 versus iodixanol-320 (aortic root, p = 0.021; left main, p = 0.032; left anterior descending, p = 0.033; left circumflex, p = 0.039; and right, p = 0.009). Analysis of coronary branch visualization revealed improved depiction for iopamidol-370 compared with iodixanol-320. CONCLUSION Iopamidol-370, with its higher iodine concentration, provided greater vascular contrast of the arterial coronary tree and improved depiction of anatomic detail without significantly impacting cardiac heart rate during coronary MDCT imaging, as compared with iodixanol-320.

Low-Dose Computed Tomographic Screening for Lung Cancer

Low-dose computed tomographic (LDCT) screening is now moving from clinical trials to clinical practice, following the report from the National Lung Screening Trial that LDCT screening for lung cancer can reduce the number of deaths from lung cancer by 20% in current and former smokers, ages 55 to 74 years, with a 30 pack-year smoking history. This article reviews the current evidence for screening, key elements of a successful lung cancer screening clinic, and reporting and management guidelines for LDCT screening findings.

Preoperative radiation therapy and chemotherapy for pulmonary blastoma: A case report

CASE PRESENTATION A 24-year-old man presented with hemoptysis. Chest radiographs revealed a right upper lobe mass. Positron emission tomography-computed tomography confirmed a 7.4-cm hypermetabolic right upper lobe mass. The patient underwent right upper lobectomy, which demonstrated a 7.7-cm pulmonary blastoma. Surgical margins and 3 N1 lymph nodes were negative. Adjuvant chemotherapy was recommended but was declined by the patient. Five years later, he again presented with significant hemoptysis. Chest computed tomography scan demonstrated an 8.9-cm right lung mass, which abutted the mediastinum (Figure 1). Positron emission tomography-computed tomography confirmed localized disease. The tumor was deemed unresectable. Biopsy to confirm disease recurrence was not performed because he was having significant hemoptysis, and the clinical picture was consistent with recurrent pulmonary blastoma. The original treatment plan was for definitive radiation therapy to a dose of 60 Gy with concurrent cisplatin and etoposide. However, his tumor regressed substantially after 2 weeks of therapy. Therefore, a preoperative course of radiation therapy and chemotherapy was pursued. The tumor was treated to a total dose of 50 Gy in 2 Gy daily fractions. He received two cycles of cisplatin (50 mg/m on days 1 and 8) and etoposide (50 mg/m on days 1–5) during weeks 1 and 5 of radiotherapy. The patient tolerated treatment exceptionally well, developing grade 2 acute esophagitis, which was managed with viscous lidocaine. Three weeks after completing preoperative therapy, a chest computed tomography was repeated showing dramatic regression of disease (Figure 2). The patient subsequently underwent surgical resection, which required a completion right pneumonectomy. Pathology revealed a 6.3-cm pulmonary blastoma with significant scarring and pleural fibrosis. His original pathology was reviewed and found to be identical. Surgical margins were negative, and there was no evidence of regional lymph node involvement. Two additional cycles of chemotherapy were recommended, which he is currently receiving.

Case of the Season: Aortoesophageal Fistula Complicating Thoracic Aortic Aneurysm Stent Graft Repair

79-year-old female with a history of gastroesophageal reflux and peptic ulcer disease presented to the emergency department with chest pain and report of two episodes of hematemesis. The patient has a history of ascending aortic aneurysm post open surgical repair by inclusion graft 10 years prior, eventually complicated by pseudoaneurysm formation at the distal anastomosis as well as development of a new 7.5 cm descending thoracic aortic aneurysm. The patient was deemed a poor surgical candidate, therefore these were treated by endovascular stent grafting of the arch and descending thoracic aorta approximately four months before the current acute presentation. The patient was hypotensive (98/54 mm Hg), tachycardic (110 bpm, regular), and mildly febrile (38°C, 100.4°F). Physical examination was notable for tenderness to palpation in the mid epigastrum. Laboratory studies revealed an elevated white blood count of 20.5 (10 9 /L). Given the low grade fever and leukocytosis, blood cultures were submitted. Hemoglobin and hematocrit were low (9.1 g/dL and 0.28 L/L, respectively). One episode of hematemesis was witnessed in the emergency room. The working clinical diagnosis was an upper gastrointestinal bleed, presumed secondary to peptic ulcer disease. The patient underwent volume resuscitation, gastric lavage and transfusion of packed red blood cells in the emergency department before consultation with Gastroenterology. Upper endoscopy was subsequently performed which demonstrated submucosal hemorrhage with adherent clot along the leftposterolateralwallofthemidesophagus;nogastriculcers

Multimodality imaging in the diagnosis of deep vein thrombosis and popliteal pseudoaneurysm complicating a sessile osteochondroma

Synergistic use of ultrasonography, radiography, multidetector CT (MDCT) and MRI enabled a prompt and accurate diagnosis of a nonocclusive popliteal vein thrombus (deep venous thrombosis, DVT) and a pseudoaneurysm complicating a sessile osteochondroma in an 11-year-old boy who presented in the emergency department with sudden-onset nontraumatic pain in the posterior aspect of the knee.