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H P McAdams

Publications and source records attributed to H P McAdams.

At least 19 recordsLinked to original sources
PubMed2006

Optimization of the matrix inversion tomosynthesis (MITS) impulse response and modulation transfer function characteristics for chest imaging.

Matrix inversion tomosynthesis (MITS) uses linear systems theory, along with a priori knowledge of the imaging geometry, to deterministically distinguish between true structure and overlying tomographic blur in a set of conventional tomosynthesis planes. In this paper we examine the effect of total scan angle (ANG), number of input projections (N), and plane separation/number of reconstructed planes (NP) on the MITS impulse response (IR) and modulation transfer function (MTF), with the purpose of optimizing MITS imaging of the chest. MITS IR and MTF data were generated by simulating the imaging of a very thin wire, using various combinations of ANG, N, and NP. Actual tomosynthesis data of an anthropomorphic chest phantom were acquired with a prototype experimental system, using the same imaging parameter combinations as those in the simulations. Thoracic projection data from two human subjects were collected for corroboration of the system response analysis in vivo. Results suggest that ANG=20 degrees, N=71, NP=69 is the optimal combination for MITS chest imaging given the inherent constraints of our prototype system. MITS chest data from human subjects demonstrates that the selected imaging strategy can effectively produce high-quality MITS thoracic images in vivo.

Algorithms↗
PubMed2001

Multidimensional imaging of the thorax: practical applications.

Over the past decade, faster CT scan times, thinner collimation, and the development of multirow detectors, coupled with the increasing capability of computers to process large amounts of data in short periods of time, have lead to an expansion in the ability to create diagnostically useful two-dimensional (2D) and three-dimensional (3D) images within the thorax. Applications within the thorax include, but are not limited to, evaluation of pulmonary and systemic vasculature, evaluation of the tracheobronchial tree, and delineation of diffuse lung disease. Pulmonary nodule volume and growth can be more accurately predicted, and represents an improvement in the evaluation of the solitary pulmonary nodule. Multiplanar images increase our understanding of thoracic anatomy and can help to guide bronchoscopic procedures. Because there are strengths and weaknesses to all the reconstruction algorithms, the utility of any given technique is dependent on the clinical question to be answered. For instance, although maximum intensity projection imaging (MIP) is helpful in the evaluation of micronodular lung disease, it is of little value in the diagnosis of aortic dissection. As the ability to generate faster and more precise multidimensional images grow, the demand for such imaging is likely to increase. In this review, the authors discuss the various reconstruction techniques available, followed by a discussion of the clinical applications.

Humans↗
PubMed2001

Reperfusion edema after lung transplantation: effect of daclizumab.

PURPOSE: To determine if daclizumab, an interleukin-2 antagonist, reduced the severity of reperfusion edema in lung transplant recipients. MATERIALS AND METHODS: Eighty-five patients who were to undergo 86 consecutive lung transplants were included; 43 (50%) received daclizumab in addition to conventional immunosuppression. Patients were assigned to one of the following groups: control, right allograft; control, left allograft; daclizumab treated, right allograft; daclizumab treated, left allograft. Radiographs obtained in the first 5 postoperative days were evaluated for degree of edema. Mean daily edema scores and curves for control and daclizumab-treated groups were compared. Differences in survival at 1, 3, 6, and 12 months after transplantation, days of mechanical ventilation, and the ratio of arterial oxygenation to inspired oxygen level at 1, 3, and 5 days after transplantation were also compared. RESULTS: Mean daily edema scores, edema curves, survival, days of mechanical ventilation, and ratio of arterial oxygenation to inspired oxygen level at 1 and 3 days after transplantation did not significantly differ between daclizumab-treated and control groups. A trend toward improved survival in the daclizumab-treated group was noted. CONCLUSION: Daclizumab had no effect on the radiographic or immediate clinical manifestations of reperfusion edema in lung transplant recipients. Additional follow-up is needed to determine if daclizumab offers any long-term benefit in terms of reduced rejection rates or survival.

Adolescent↗
PubMed2001

Complications (excluding hyperinflation) involving the native lung after single-lung transplantation: incidence, radiologic features, and clinical importance.

PURPOSE: To determine the incidence, importance, and radiologic features of native lung complications after single-lung transplantation. MATERIALS AND METHODS: Seventeen (15%) of 111 single-lung transplant recipients developed native lung complications (excluding hyperinflation) 0-58 months (mean, 17 months) after transplantation. Complaints at presentation, culture or histopathologic results, diagnostic or therapeutic procedures, and outcome were recorded. Chest radiographs (n = 17) and computed tomographic (CT) scans (n = 8) obtained at time of diagnosis were reviewed. Serial radiographs were assessed for disease progression or improvement. RESULTS: The most common complications were infection (n = 10), caused by bacteria (n = 4), fungi (n = 4), or mycobacteria (n = 2), typically manifested as lobar or segmental opacities on chest radiographs or CT scans. Lung cancer manifested as a solitary well-circumscribed nodule (n = 1), multiple nodules (n = 1), or a hilar mass (n = 1). Five (29%) of 17 patients died of native lung complications. Seven patients underwent mediastinoscopy (n = 3), lobectomy (n = 2), thoracoscopic wedge resection (n = 2), tube thoracostomy (n = 2), or pneumonectomy (n = 1) for diagnosis or treatment. CONCLUSION: Native lung complications occurred in 17 (15%) single-lung transplant recipients, were most commonly due to infection or lung cancer, and caused serious morbidity or mortality in 12 (71%) of 17 patients affected.

Adult↗
PubMed2001

Frequency and CT findings of recurrent disease after lung transplantation.

PURPOSE: To determine the frequency and computed tomographic (CT) findings of recurrence of the primary disease after lung transplantation at six North American lung transplantation centers. MATERIALS AND METHODS: Medical records of 1,394 lung transplant recipients were reviewed to identify patients with recurrent primary disease. Their CT scans and pathologic specimens were reviewed. RESULTS: The frequency of disease recurrence in the six transplantation centers was 1% (15 of 1,394 patients), including six previously reported cases. Sarcoidosis recurred in nine (35%) of 26 transplants and was the most common disease to recur. Three (33%) of nine patients with recurrent sarcoidosis had correlative findings at CT. When present, CT findings were usually different at recurrence compared with pretransplantation CT findings. CONCLUSION: A relatively small percentage of patients are at risk for recurrence of primary disease following lung transplantation. Sarcoidosis is the most common disease to recur.

Adult↗
PubMed2001

CT fluoroscopy--guided interventional procedures: techniques and radiation dose to radiologists.

PURPOSE: To determine the radiation dose to radiologists who perform computed tomographic (CT) fluoroscopic interventional procedures by using a quick-check method and a low-milliampere technique. MATERIALS AND METHODS: Two hundred twenty CT fluoroscopy--guided interventional procedures were performed in 189 patients. Procedures included 57 spinal injections, 17 spinal biopsies, 24 chest biopsies, 20 abdominal aspirations, 44 abdominal biopsies, and 58 abdominal drainages. Procedure details were prospectively recorded and included site, depth, target diameter, milliampere value, kilovolt peak, fluoroscopic time, and CT technique (continuous CT fluoroscopy, quick-check method, or a combination of these techniques). An individual collar and finger radiation detector were worn by each radiologist during each procedure to determine the dose per procedure. RESULTS: The quick-check technique was performed in 191 (87%) of 220 procedures. Four procedures were performed with continuous CT fluoroscopy, and a combination technique was used for 25 (11%) procedures. The overall mean CT fluoroscopic time was 17.9 seconds (range, 1.2--101.5 seconds). The mean milliampere value was 13.2 mA (range, 10--50 mA). The overall mean radiologist radiation dose per procedure was 2.5 mrem (0.025 mSv) (whole body). Individual procedure doses ranged from 0.66 to 4.75 mrem (0.007--0.048 mSv). The finger radiation dose was negligible. CONCLUSION: By using a low-milliampere technique and the quick-check method, CT fluoroscopic time and radiation exposure can be minimized.

Adult↗
PubMed2001

Influenza pneumonia in lung transplant recipients: clinical features and association with bronchiolitis obliterans syndrome.

Influenza infection is increasingly recognized to cause significant morbidity and mortality in the community, especially in pediatric patients and elderly persons. Influenza infection, however, has not been well described among thoracic organ transplant recipients. We provide the first detailed clinical, radiographic, and histologic description of influenza pneumonia among three lung transplant recipients. The presentation varied considerably among the three patients and, in some cases, was atypical for influenza. Despite treatment, a persistent decline in pulmonary function occurred in all three patients after the acute illness. Interestingly, on follow-up biopsy specimens, each patient had histologic evidence of acute rejection and/or obliterative bronchiolitis. Additional research, therefore, is needed to clarify the relationship between influenza infection, acute rejection, and obliterative bronchiolitis.

Biopsy, Needle↗
PubMed2001

Congenital unilateral pulmonary vein atresia: radiologic findings in three adult patients.

OBJECTIVE: The purpose of our study is to describe the radiologic findings of adult patients presenting with congenital unilateral pulmonary vein atresia. CONCLUSION: Chest radiography in affected patients typically reveals a small hemithorax and ipsilateral pulmonary artery as well as ipsilateral septal thickening. CT shows, in addition, ground-glass attenuation, the absence of a pulmonary vein connection to the left atrium, and abundant mediastinal venous collateral vessels. MR imaging is helpful in further characterizing the vascular abnormalities. Angiography may help to confirm the diagnosis.

Adult↗
PubMed2001

Idiopathic multilocular thymic cyst: CT features with clinical and histopathologic correlation.

OBJECTIVE: We performed this study to describe the CT features of idiopathic multilocular thymic cysts with clinical and histopathologic correlation. CONCLUSION: Multilocular thymic cysts typically manifest on CT as unilocular or multilocular cystic thymic masses, often with soft-tissue attenuation components. CT cannot be used to distinguish neoplastic from nonneoplastic soft-tissue components.

Adolescent↗
PubMed2001

Integration of peripheral blood biomarkers with computed tomography to differentiate benign from malignant pulmonary opacities.

Our purpose was to determine whether peripheral blood biomarkers MUC1 and CK19 could be used to complement imaging studies in differentiating benign from malignant indeterminate pulmonary nodules or masses detected on computed tomography CT. One hundred and eighteen patients had a thoracic CT and blood drawn for tumor marker reverse transcriptase-polymerase chain reaction analysis. Thirty-five of the 118 patients had an indeterminate pulmonary nodular opacity on CT, and the findings then were correlated with the reverse transcriptase-polymerase chain reaction results. The sensitivity and specificity for the markers in determining malignancy was calculated. Thirteen of the 35 opacities on CT proved to be benign, and 22 proved to be lung cancer. Among the patients with indeterminate pulmonary abnormalities, polymorphic epithelial mucin protein 1 had a sensitivity and specificity for lung cancer of 100% and 46%, respectively. Cytokeratin 19 had a sensitivity and specificity for lung cancer of 95% and 8%, respectively. These preliminary data showed that serum biomarkers polymorphic epithelial mucin protein 1 and cytokeratin 19 were not specific for lung cancer, although patients with an indeterminate pulmonary abnormality and negative markers were unlikely to have lung cancer. Integration of imaging studies with the appropriate biomarkers may prove useful in evaluating indeterminate pulmonary nodules or masses.

Adult↗
PubMed2000

Percutaneous management of intrapulmonary air and fluid collections.

The radiologist's role in the management of intrapulmonary air and fluid collections is becoming more important. Improvements in percutaneous interventional techniques now allow the radiologist to offer patients an alternative treatment option with less morbidity and mortality than surgical resection. The use of CT allows optimal catheter placement and enables safe and effective percutaneous evacuation of intrapulmonary collections. In summary, image-guided percutaneous catheter drainage should (1) be the initial procedure performed to diagnose and treat lung abscesses not responding to conservative therapy; and (2) because of its effectiveness and safety, be considered as a treatment option in the management of symptomatic patients with intrapulmonary mycetomas.

Aspergillosis↗
PubMed2000

Non-small cell lung cancer: FDG PET for nodal staging in patients with stage I disease.

PURPOSE: To determine the accuracy of 2-[fluorine-18]fluoro-2-deoxy-D-glucose (FDG) positron emission tomography (PET) in the evaluation of regional lymph nodes in patients with stage I non-small cell lung cancer (NSCLC). MATERIALS AND METHODS: Imaging and clinical findings obtained during 5 years in 84 patients (mean age, 66 years) were reviewed. Patients had thoracic computed tomographic findings of stage I NSCLC, an FDG PET study, and histopathologic proof of lung cancer. At the time of diagnosis, disease stage was assigned on the basis of FDG PET results and was compared with the histopathologic stage to determine the accuracy of PET. RESULTS: When PET stage was compared with histopathologic stage, the disease in 72 (86%) patients was accurately staged with PET, understaged in two (2%), and overstaged in 10 (12%). The overall sensitivity, specificity, and positive and negative predictive values for PET of regional lymph nodal metastases were 82%, 86%, 47%, and 97%, respectively. CONCLUSION: FDG PET enables accurate staging of regional lymph node disease in patients with stage I NSCLC. A negative PET scan in these patients suggests that mediastinoscopy is unnecessary and that these patients can proceed directly to thoracotomy.

Aged↗
PubMed2000

Bronchogenic cyst: imaging features with clinical and histopathologic correlation.

PURPOSE: To characterize the imaging features of bronchogenic cysts. MATERIALS AND METHODS: The computed tomographic (CT) and/or magnetic resonance (MR) or ultrasonographic images in 68 histopathologically proved cases of bronchogenic cyst in 38 male and 30 female patients, aged newborn to 72 years (mean, 22 years), were retrospectively reviewed. RESULTS: There were 58 mediastinal and 10 extramediastinal cysts. At CT (n = 62), 60 cysts were sharply marginated with smooth (n = 35) or lobulated (n = 25) borders. Twenty-five cysts were of water attenuation, 25 were of soft-tissue attenuation, two were air filled, two had an air-fluid level, and two had dependent milk of calcium. On T1-weighted MR images (n = 23), 18 cysts were hyperintense and five were isointense to cerebrospinal fluid. On T2-weighted MR images (n = 18), 17 cysts were isointense or hyperintense to cerebrospinal fluid. Of the 25 soft-tissue-attenuation lesions at CT, 11 appeared cystic because of internal homogeneity, lack of internal enhancement, mural enhancement, and characteristic location. Fourteen appeared solid based on morphology and attenuation. MR imaging of nine of the latter showed marked hyperintensity on T2-weighted images. CONCLUSION: CT of bronchogenic cysts typically shows sharply marginated mediastinal masses of soft-tissue or water attenuation. Most appear cystic. A minority appear solid and can be confused with other lesions; MR imaging can be useful for elucidating the cystic nature of these lesions.

Adolescent↗