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Biomedical subjects

W Richard Webb

Publications and source records attributed to W Richard Webb.

At least 19 recordsLinked to original sources
PubMed2006

Thin-section CT of the secondary pulmonary lobule: anatomy and the image--the 2004 Fleischner lecture.

The secondary pulmonary lobule is a fundamental unit of lung structure, and it reproduces the lung in miniature. Airways, pulmonary arteries, veins, lymphatics, and the lung interstitium are all represented at the level of the secondary lobule. Several of these components of the secondary lobule are normally visible on thin-section computed tomographic (CT) scans of the lung. The recognition of lung abnormalities relative to the structures of the secondary lobule is fundamental to the interpretation of thin-section CT scans. Pathologic alterations in secondary lobular anatomy visible on thin-section CT scans include interlobular septal thickening and diseases with peripheral lobular distribution, centrilobular abnormalities, and panlobular abnormalities. The differential diagnosis of lobular abnormalities is based on comparisons between lobular anatomy and lung pathology.

Humans↗
PubMed2006

Lymphoepithelioma-like carcinoma of the lung: radiologic features of an uncommon primary pulmonary neoplasm.

OBJECTIVE: The purpose of this study was to review the chest radiographic, CT, and MRI appearances of primary pulmonary lymphoepithelioma-like carcinoma (LELC). CONCLUSION: Primary pulmonary LELC is histopathologically identical to nasopharyngeal carcinoma. The radiographic, CT, and MRI features of primary pulmonary LELC are nonspecific, often resembling those of bronchogenic carcinoma. Primary pulmonary LELC usually presents as a poorly circumscribed, enhancing, peripheral solitary pulmonary nodule on CT; necrosis may be present and is considered a poor prognostic sign. MRI shows isointense to low-intensity signal on T1-weighted images and mildly increased signal on T2-weighted images; enhancement of abnormal tissue is typical. Most patients present with early-stage disease. Primary pulmonary LELC should be suspected in selected patients and requires differentiation from bronchogenic carcinoma and metastatic nasopharyngeal carcinoma.

Carcinoma↗
PubMed2005

High-resolution computed tomography in idiopathic pulmonary fibrosis: diagnosis and prognosis.

RATIONALE: High-resolution computed tomography (HRCT) is an integral aspect of the evaluation of patients with suspected idiopathic pulmonary fibrosis (IPF). However, few studies have evaluated its use in a large cohort. OBJECTIVES: To describe HRCT features in patients with mild to moderate IPF, compare diagnostic evaluations by a radiology core (three thoracic radiologists) with those by study-site radiologists, correlate baseline clinical and physiologic variables with HRCT findings, and evaluate their association with mortality. METHODS: We assessed HRCT scans from patients with IPF (n = 315) enrolled in a randomized controlled study evaluating IFN-gamma1b. MEASUREMENTS AND MAIN RESULTS: There was concordance between study-site and core radiologists regarding the diagnosis of IPF in 86% of cases. Diffusing capacity of carbon monoxide (DLCO) was the physiologic characteristic most highly correlated with HRCT findings. Multivariate analysis identified three independent predictors of mortality: a higher extent of fibrosis score increased the risk of death (p < 0.0001), whereas a higher percent-predicted DLCO (p = 0.004) and treatment assignment to IFN-gamma1b rather than placebo (p = 0.04) reduced the risk of death. CONCLUSIONS: A study-site diagnosis of IPF on HRCT was regularly confirmed by core radiologists. Extent of reticulation and honeycombing on HRCT is an important independent predictor of mortality in patients with IPF.

Female↗
PubMed2005

Patterns of surgical care of lung cancer patients.

BACKGROUND: This survey was performed to determine the patterns of surgical care provided patients with non-small cell lung carcinoma (NSCLC). METHODS: In 2001, the American College of Surgeons carried out a patient care survey of 729 hospitals to retrieve information of NSCLC patients' history, evaluation, pathology, and surgical treatment. RESULTS: Inclusion criteria were met by 40,090 patients: of whom 11,668 (29.1%) were treated surgically; 74.2% alone and 25.8% as part of multimodality therapy. Of these patients, 59.5% were in stage I, 17.5% in stage II, 17.0% in stage III, and 6.0% in stage IV. Surgery patient demographics were the following: 55% male and 45% female; 46.8% 70 years or older; and 76.3% had significant comorbidities. Tumor characteristics: squamous 28%, adenocarcinoma 37.6%, other 34.4%. Staging: in addition to radiologic examinations, preoperative mediastinoscopy was performed in 27.1% of operated patients with node biopsy in only 46.6% of these procedures. OPERATIONS: wedge resection 15.6%, lobectomy 70.8%, pneumonectomy 13.6%. Surgical margins were positive in 7.8%, but only 65.2% had frozen section analysis. Perioperative mortality was 5.2%, but was 4.0% in nontransfused patients and 12.7% in transfused patients and was 3.2% in high-volume (more than 90 operations per year) versus 4.8% in low-volume hospitals (p < 0.001). CONCLUSIONS: (1) Patients being operated for NSCLC are elderly with significant comorbid conditions. (2) More patients than previously are female and have adenocarcinoma. (3) Mediastinoscopy is infrequently performed and lymph nodes are biopsied in less than 50% of them. (4) Lobectomy is the most common operation, and positive surgical margins are too frequent. (5) Operative mortality is reasonable but transfusion is a marker for increased risk and outcomes are superior in high-volume hospitals. (6) Hospitals with higher volume had fewer perioperative deaths.

Adolescent↗
PubMed2005

High-resolution CT of the lung: patterns of disease and differential diagnoses.

High-resolution CT (HRCT) of the lung is a powerful tool for the investigation of patients with acute or chronic respiratory symptoms or diffuse parenchymal lung disease. Detailed knowledge of normal pulmonary anatomy and an understanding of how normal anatomy is altered in disease states are required to appreciate fully HRCT findings in patients with pulmonary disease. Detailed knowledge of the technical aspects of HRCT examinations is required for optimal image quality. With the proper foundation, a pattern approach to HRCT interpretation may then be used successfully to provide accurate and reproducible interpretation.

Diagnosis, Differential↗
PubMed2005

Imaging findings in Takayasu's arteritis.

OBJECTIVE: The objective of our study was to evaluate the clinical usefulness of cross-sectional imaging for establishing the diagnosis of Takayasu's arteritis (TA), an inflammatory vascular disorder that produces arterial stenoses and aneurysms primarily involving the thoracoabdominal aorta and its branches and the pulmonary arteries. CONCLUSION: CT and MRI findings of TA include vascular wall thickening and enhancement early in the disease, and arterial stenoses, occlusions, and aneurysms later in the disease. Cross-sectional imaging is useful for establishing the diagnosis of TA and for showing response to nonsurgical therapy or for planning a surgical intervention.

Adult↗
PubMed2003

Helical CT pulmonary angiography predictors of in-hospital morbidity and mortality in patients with acute pulmonary embolism.

PURPOSE: To determine if CT variables predict in-hospital morbidity and mortality in patients with pulmonary embolism (PE). MATERIALS AND METHODS: CT scans and charts of 173 patients with CT scans positive for PE were reviewed. CT scans were reviewed for leftward ventricular septal bowing, increased right ventricle (RV) to left ventricle (LV) diameter ratio, clot burden, increased pulmonary artery to aorta diameter ratio, and oligemia. Charts were reviewed for severe morbidity and mortality outcomes: death from pulmonary emboli or any cause, and cardiac arrest. Charts were also reviewed for milder morbidity outcomes: intubation, vasopressor use, or admission to an intensive care unit (ICU) and for multiple comorbidities. RESULTS: No CT predictor was significantly associated with severe morbidity or mortality outcomes. Ventricular septal bowing and increased RV/LV diameter ratio were both associated with subsequent admission to an ICU (P = 0.004 and P = 0.025, respectively). Oligemia (either lung) was associated with subsequent intubation; right lung oligemia was associated with the subsequent use of vasopressors. After controlling for history of congestive heart failure, ischemic heart disease, and pulmonary disease, both septal bowing and an increased RV/LV diameter ratio remained associated with admission to an ICU. CONCLUSION: No CT variables predicted severe in-hospital morbidity and mortality (death from pulmonary embolism, death from any cause, or cardiac arrest) in patients with PE. However, ventricular septal bowing and increased RV/LV diameter ratio were both strongly predictive of less severe morbidity, namely, subsequent ICU admission, and oligemia was associated with subsequent intubation and vasopressor use.

Acute Disease↗
PubMed2002

Clinical and radiographic predictors of the etiology of computed tomography-diagnosed intrathoracic lymphadenopathy in HIV-infected patients.

In HIV-infected patients with intrathoracic lymphadenopathy, it is not known whether clinical and radiographic findings are useful in predicting a specific diagnosis. We determined the etiology and predictors of the etiology of computed tomography (CT)-diagnosed intrathoracic lymphadenopathy in HIV-infected patients evaluated from June 1993 through April 1999. Multivariate analyses were performed to determine clinical and radiographic predictors of the three most common diagnoses. Of 318 patients, 110 (35%) had lymphadenopathy on chest CT. Among these 110 patients, tuberculosis/nontuberculous mycobacterial disease ( = 31), bacterial pneumonia ( = 26), and lymphoma ( = 21) were the most common diagnoses. Multivariate analysis identified cough and necrosis of lymph nodes on chest CT as independent predictors of tuberculosis/nontuberculous mycobacterial disease. African-American race, symptoms for 1 to 7 days, dyspnea, and presence of airways disease on chest CT were independent predictors of bacterial pneumonia; symptoms for >7 days, absence of cough, and absence of pulmonary nodules on CT independently predicted lymphoma. Intrathoracic lymphadenopathy is a frequent chest CT finding in HIV-infected patients. Opportunistic infections and lymphoma are the most common causes, and specific clinical and radiographic features can suggest these particular diagnoses.

AIDS-Related Opportunistic Infections↗
PubMed2002

Thoracic complications of illicit drug use: an organ system approach.

Illicit drug use constitutes a major health problem and may be associated with various thoracic complications. These complications vary depending on the specific drug used and the route of administration. Commonly abused drugs that may play a role in causing thoracic disease include cocaine, opiates, and methamphetamine derivatives. Intravenously abused oral medications may contain filler agents that may be responsible for disease. Thoracic complications may be categorized as pulmonary, pleural, mediastinal, cardiovascular, and chest wall complications. Pulmonary complications of drug abuse include pneumonia, cardiogenic edema, acute lung injury, pulmonary hemorrhage, and aspiration pneumonia. Filler agents such as talc may result in panacinar emphysema or high-attenuation upper-lobe conglomerate masses. The primary pleural complication of illicit drug use is pneumothorax. Mediastinal and cardiovascular complications of illicit drug use include pneumomediastinum, cardiomyopathy, myocardial infarction, aortic dissection, and injection-related pseudoaneurysms. Chest wall complications include diskitis and vertebral osteomyelitis, epidural abscess, necrotizing fasciitis, costochondritis, and septic arthritis. Categorization of thoracic complications of illicit drug use may facilitate understanding of these disorders and allow accurate diagnosis.

Aortic Dissection↗
PubMed2002

Tracheal compression by the stomach following gastric pull-up: diagnosis with CT and treatment with expandable metallic stent placement.

Surgical treatment of recurrent achalasia includes esophagectomy with gastric pull-up. A MEDLINE search yielded no articles describing an adverse effect of this surgery on pulmonary function. We report the first case of acute ventilatory failure caused by gastric pull-up. An evaluation by flexible bronchoscopy, spirometry with flow-volume loops, and dynamic CT scanning revealed extrinsic compression of the trachea by the stomach causing obstruction. Endotracheal placement of a self- expanding stent resulted in the rapid extubation of the patient with normalization of the flow-volume loop and dramatic improvement in the FVC, FEV(1), and peak expiratory flow.

Constriction, Pathologic↗
PubMed2002

Air trapping on CT of patients with pulmonary embolism.

OBJECTIVE: We evaluated the relationship of air trapping to mosaic perfusion in patients with pulmonary embolism. SUBJECTS AND METHODS: Forty-one consecutive patients with suspected pulmonary embolism underwent expiratory CT followed by helical CT angiography. After excluding 12 patients who had airway disease or were smokers, we divided the patients into two groups: those with (n = 15) and without (n = 14) pulmonary embolism. For each patient, six expiratory images were evaluated for the presence of air trapping, and the corresponding six images from CT angiography were evaluated for the presence of mosaic perfusion. Clot locations were assessed on CT angiography and were correlated with the presence of air trapping and mosaic perfusion. RESULTS: In patients with pulmonary embolism, mosaic perfusion was identified in 32 areas (seven patients, 46.7%), and air trapping was identified 68 areas (nine patients, 60%). Of the 32 areas of mosaic perfusion, 23 areas (71.9%) showed air trapping on expiratory CT scans. Of the 68 areas with air trapping on expiratory scans, 23 areas (33.8%) showed mosaic perfusion on inspiratory scans, and 44 areas (64.7%) had clots in the arteries leading to them. Clots were more frequently identified in areas of lower attenuation on inspiratory CT scans and air trapping (21/23) than in those of normal attenuation on inspiratory CT scans and air trapping (23/45) (p < 0.005). Only one patient without pulmonary embolism had air trapping (p < 0.005). CONCLUSION: Air trapping is common in pulmonary embolism and may be the cause of mosaic perfusion. Air trapping can be seen distal to vessels not showing pulmonary embolism.

Adolescent↗
PubMed2002

Helical CT with sagittal and coronal reconstructions: accuracy for detection of diaphragmatic injury.

OBJECTIVE: The objectives of our study were to determine the accuracy of single-detector helical CT (including coronal and sagittal reconstructions) for the diagnosis of traumatic diaphragmatic injury, establish measurements for the thickness of the normal diaphragmatic crus, and describe an additional sign of diaphragmatic injury: active arterial extravasation of contrast material at the level of the diaphragm. MATERIALS AND METHODS: The CT scans of 25 patients with surgically proven diaphragmatic injury and 22 patients with surgically confirmed uninjured diaphragms were blindly reviewed by five thoracic radiologists. Sagittal and coronal reconstructions were performed for 20 of the 25 patients with a proven diaphragmatic injury and for all the patients without a diaphragmatic injury. Scans were evaluated for findings suggestive of diaphragmatic injury and for associated injuries. Reviewers scored the usefulness of the reconstructed images for establishing the final diagnosis. Measurements of the right and left crura were performed to establish a threshold measurement that would enable radiologists to discriminate between a normal diaphragm and an injured diaphragm. RESULTS: The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of helical CT were 84%, 77%, 81%, 81%, and 83%, respectively. Scans showing active arterial extravasation of contrast material enabled reviewers to correctly identify diaphragmatic injury in two patients. Reconstructed images confirmed the correct diagnosis in three patients but supported an incorrect diagnosis in two. The mean thickness of the diaphragmatic crura (right and left) was not significantly greater in patients with an injured diaphragm than in those with an uninjured diaphragm. CONCLUSION: Helical CT shows good sensitivity, specificity, and accuracy for the diagnosis of diaphragmatic injury. Coronal and sagittal reconstructions are of limited use in establishing or refuting this diagnosis. Active arterial extravasation of contrast material near the diaphragm should raise suspicion for injury. Crus measurements cannot be used to reliably distinguish between injured and uninjured diaphragms.

Adolescent↗
PubMedDate not supplied

The radiologic spectrum of pulmonary Aspergillus infections.

Aspergillus infections may be categorized by specific radiographic patterns, the patient's immunologic status, and the presence or absence of preexisting structural lung disease. General patterns include invasive aspergillosis (both vascular and airway invasive varieties and acute tracheobronchitis), semiinvasive aspergillosis (including allergic bronchopulmonary aspergillosis and hypersensitivity pneumonitis), mycetoma, allergic aspergillosis, and obstructing bronchial aspergillosis. Knowledge of these various radiographic patterns as well as the immune derangements that accompany these infections may allow proper diagnosis.

Aspergillosis, Allergic Bronchopulmonary↗
PubMedDate not supplied

Benign tracheobronchial stenoses: changes in short-term and long-term pulmonary function testing after expandable metallic stent placement.

PURPOSE: To determine the short- and long-term improvement in airflow dynamics in patients undergoing tracheobronchial stent placement for benign airway stenoses. METHODS: Twenty-two patients underwent 34 tracheal and/or bronchial stent placement procedures for benign airway stenoses and had the results of pulmonary function tests available. Stent placement indications included bronchomalacia after lung transplantation (n = 11), postintubation stenoses (n = 6), relapsing polychondritis (n = 2), and 1 each of tracheomalacia, tracheal compression, and histoplasmosis. Six patients underwent more than one stent placement procedure (range: 2-7 procedures). The mean forced expiratory volume in one second (FEV(1) ), forced expiratory flow rate in the midportion of the forced vital capacity curve (FEF(25-75) ), forced vital capacity, and peak flow (PF) rate obtained before stent placement were compared with those immediately after stent placement and with those measurements most remote from stent placement using the paired two-tailed test. RESULTS: All patients reported improved respiratory function immediately after stent placement. The mean FEV(1), FEF(25-75), and PF rate improved significantly (p < 0.001, p = 0.002, and p = 0.009, respectively) after stent placement. On long-term follow-up averaging 15 months after stent placement, these parameters declined despite patients' subjective sense of improvement. Segregating the population into transplant and nontransplant airway stenosis etiologies, however, FEF(25-75) and PF rate remained significantly improved (p = 0.045, p = 0.027, respectively), over the long term for the latter. FEV increased after subsequent stent placements for patients receiving multiple stents. CONCLUSION: Stent placement for benign tracheobronchial stenoses provides significant immediate improvement in airflow dynamics. Long-term improvement in airflow obstruction may be expected, and additional stent placements may further improve pulmonary function.

Adult↗
PubMedDate not supplied

Malignant pleural mesothelioma: evaluation with CT, MR imaging, and PET.

Imaging plays an essential role in the evaluation of malignant pleural mesothelioma (MPM). Computed tomography is the primary imaging modality used for the diagnosis and staging of MPM. Magnetic resonance (MR) imaging and, more recently, positron emission tomography (PET) have emerged as modalities that can provide additional important diagnostic and prognostic information to help further delineate the extent of disease, especially in surgical candidates. Use of MR imaging performed with different pulse sequences and gadolinium-based contrast material can improve the detection of tumor extension, especially to the chest wall and diaphragm. PET can provide both anatomic and metabolic information, especially in cases of extrathoracic and mediastinal nodal metastasis. Each imaging modality has its advantages and limitations, but their combined use is crucial in determining the most appropriate treatment options for patients with MPM.

Aged↗