Nerves of the thorax: atlas of normal and pathologic findings.

An anatomic and imaging atlas was created to provide detailed information about the six pairs of thoracic nerves (phrenic nerves, vagus nerves, recurrent laryngeal nerves, sympathetic trunks, costal nerves, long thoracic nerves). Serial axial computed tomographic (CT) scans of the normal thorax were obtained and included in the atlas, along with drawings showing the proper location of each nerve relative to adjacent anatomic structures. CT scans obtained in both symptomatic and asymptomatic patients with various thoracic diseases were paired with appropriate drawings and normal CT scans in the atlas. This format was designed to help determine the presence and severity of related disease, including injury from surgery, trauma, or penetrating injury, metastatic disease involvement, and, rarely, primary tumor. Although the nerves of the thorax are rarely identified at cross-sectional imaging, their location can be inferred by localizing easily identified anatomic landmarks. Familiarity with the functional anatomy and clinical significance of the nerves of the thorax is important for the correct interpretation of thoracic images.

Radiologic determination of intravascular volume status using portable, digital chest radiography: a prospective investigation in 100 patients.

OBJECTIVE: To answer the following questions: Can the digital chest roentgenogram (CXR) be used to differentiate patients' volume status? Do clinical data alter radiologists' accuracy in interpreting the digital CXR? DESIGN: Prospective cohort study. SETTING: Nine adult intensive care units of a tertiary care medical center. PATIENTS: One hundred thirty-five consecutive patients with pulmonary artery catheters, of whom 35 were excluded because of unacceptable pulmonary artery occlusion pressure (PAOP) tracings. METHODS: Each patient had a portable, anteroposterior, supine digital CXR. Clinicians evaluated volume status and then measured hemodynamic data within 1 hr of the CXR. Digital CXRs were independently interpreted on two separate occasions (with and without clinical information) by three experienced chest radiologists, and these interpretations were compared with hemodynamic data. RESULTS: Of the 100 patients, 39 had PAOP >18 mm Hg, whereas 61 had PAOP <18 mm Hg. Radiologists' accuracy in differentiating volume status increased with incorporation of clinical data (56% without vs. 65% with clinical data, p =.009). Using objective receiver operating characteristic-derived cutoffs of 70 mm for vascular pedicle width and 0.55 for cardiothoracic ratio, radiologists' accuracy in differentiating PAOP >18 mm Hg from PAOP <18 mm Hg was 70%. The intrareader and the inter-reader correlation coefficients were very high. The likelihood ratio of the CXR in determining volume status using the objective vascular pedicle width and cardiothoracic ratio measures was 3.1 (95% confidence interval, 1.9-6.0), significantly higher than subjective CXR interpretations with and without clinical data (p <.001). CONCLUSIONS: Differentiating intravascular volume status with portable, supine, digital CXRs may be improved by using objective cutoffs of vascular pedicle width >70 mm and cardiothoracic ratio >0.55 or by incorporating clinical data.

Acquired tracheomalacia: detection by expiratory CT scan.

PURPOSE: The purpose of this work was to determine whether cross-sectional area and coronal and sagittal diameter measurements of the trachea between inspiration and end-expiration on CT are significantly different between patients with acquired tracheomalacia and those without this condition. METHOD: Inspiratory and end-expiratory CT scans of the trachea of 23 normal patients and 10 patients with acquired tracheomalacia were analyzed. Percent changes in cross-sectional area, coronal, and sagittal diameters were calculated. RESULTS: For patients with tracheomalacia, mean percent changes in the upper and middle trachea between inspiration and expiration were 49 and 44%; mean changes in the coronal and sagittal diameters in the upper and middle tracheal were 4 and 10% and 39 and 54%, respectively. Control group mean percent changes in the upper and middle tracheal area were 12 and 14%, respectively, and mean changes in the coronal and sagittal diameters in the upper and middle trachea were 4 and 4% and 11 and 13%, respectively. Significant differences were calculated for changes in cross-sectional area and sagittal diameter between groups (p < 10-5). Based on receiver operator curve analysis, a > 18% change in the upper trachea and 28% change in the midtrachea between inspiration and expiration were observed; the probability of tracheomalacia was 89-100%. The probability of tracheomalacia was > 89%, especially if the change in sagittal diameter was > 28%. CONCLUSION: By measuring changes in tracheal cross-sectional area and sagittal diameters between inspiratory and end-expiratory CT, a significant difference can be identified between normal patients and those with acquired tracheomalacia.

Reconciliation of the anatomic, surgical, and radiographic classifications of the mediastinum.

The mediastinum is a complex region that is variously subdivided by radiologists, surgeons and anatomists. This paper describes the most popular of these classifications and color-codes the radiologic and surgical divisions on 22 labeled axial sections of the chest. This allows the reader to quickly name the appropriate location of a lesion on any section.

Factors influencing pneumothorax rate at lung biopsy: are dwell time and angle of pleural puncture contributing factors?

PURPOSE: To study factors that may influence pneumothorax and chest tube placement rate, especially needle dwell time and pleural puncture angle. MATERIALS AND METHODS: In 159 patients, 160 coaxial computed tomography (CT)-guided lung biopsies were performed. Dwell time, the time between pleural puncture and needle removal, was calculated. The smallest angle of the needle with the pleura ("needle-pleural angle") was measured. These and other variables were correlated with pneumothorax and chest tube rates. RESULTS: One hundred fifty biopsies were included. There were 58 (39%) pneumothoraces (14 noted only at CT), with eight (5%) biopsies resulting in chest tube placement. Longer dwell times (mean, 29 minutes; range, 12-66 minutes) did not correlate with pneumothoraces (P =.81). Smaller needle-pleural angles (< 80 degrees) [corrected], decreased forced expiratory volume in 1 second to vital capacity ratio (<50%), lateral pleural puncture, and lesions along fissures were associated with higher [corrected] pneumothorax rates (P <.05). Emphysema along the needle path, pulmonary function tests showing ventilatory obstruction, and lesions along fissures predisposed patients to chest tube placement (P <.05). Pleural thickening and prior surgery were associated with lower pneumothorax rates (P <.05). CONCLUSION: Longer dwell times do not correlate with pneumothorax and should not influence the decision to obtain more biopsy samples. A shallow pleural puncture angle may increase the pneumothorax rate.

Virtual bronchoscopy.

The sophistication of three-dimensional (3-D) radiographic imaging from CT data has accelerated with the development and ongoing advances of helical CT. Virtual bronchoscopy (VB), the ability to create 3-D models of the airways and navigate through the tracheobronchial tree lumen in realtime simulated bronchoscopy, has gained popularity over the past 3 years. The ability of VB to image the airway and mediastinal structures simultaneously and in a 3-D format has helped revolutionize CT imaging. Unlike conventional bronchoscopy, VB can display the extent of narrowing caused by an airway lesion, the presence of patentcy beyond a stenosis, and the relationship between an airway lesion and the adjacent mediastinal structures.

High-resolution inspiratory and expiratory CT in older children and adults with bronchopulmonary dysplasia.

OBJECTIVE: The objective of this study is to correlate high-resolution inspiratory and expiratory CT findings with pulmonary function results in older children and adults who have bronchopulmonary dysplasia. SUBJECTS AND METHODS: High-resolution inspiratory and expiratory CT of the thorax was performed prospectively on 26 patients (16 male, 10 female) with a clinical history of bronchopulmonary dysplasia. The median age was 10 years old (range, 5-18 years). High-resolution CT during inspiration was scored for areas of decreased density and evidence of interstitial lung disease; expiratory CT was scored for air trapping. Findings were correlated with pulmonary function measurements and clinical history. RESULTS: Twenty-four (92%) of the 26 patients had abnormal CT findings. Of these 24, 22 had reticular opacities and 18 had areas of architectural distortion. Twenty patients had areas of relatively decreased density. In 24 patients, air trapping was seen on expiratory CT. Abnormal pulmonary function correlated significantly (p < .05) with abnormal decreases in density, air trapping on expiratory CT, and architectural distortion. CONCLUSION: Abnormal findings on inspiratory and expiratory high-resolution CT of older children with bronchopulmonary dysplasia include scarring and air trapping with architectural distortion. The correlation between these findings and physiologic evidence of air trapping and obstructive lung disease was statistically significant.

The CT appearance of pleural and extrapleural disease in lymphoma.

OBJECTIVE: Pleural effusions in patients with lymphoma that are assumed to be related to malignancy are attributed to either lymphatic obstruction by tumour with resultant decreased clearance of pleural fluid, or direct tumour involvement of the pleura. The purpose of our study was to determine how often pleural or extrapleural disease was detected by computed tomography (CT) of patients with pleural effusions and primary or recurrent lymphoma. METHODS AND MATERIALS: We reviewed CT examinations showing evidence of pleural effusion in 61 patients with a diagnosis of primary or recurrent lymphoma and no history of other systemic disorders, including infection. The study population consisted of patients with non-Hodgkin's lymphoma (n = 44) or Hodgkin's disease (n = 17); both primary disease (n = 11) and recurrent disease (n = 50) were represented. Each CT examination was evaluated for the presence of disease involving the visceral and parietal pleura and extrapleural space, mediastinal adenopathy, and pulmonary parenchymal disease. RESULTS: Fourteen patients (23%) (nine with non-Hodgkin's lymphoma and five with Hodgkin's disease) had parietal pleural disease (thickening or nodules). Eighteen patients (30%) (14 with non-Hodgkin's lymphoma, four with Hodgkin's disease) had tumour or enlarged lymph nodes in the extrapleural space. Forty-three patients (70%) had mediastinal lymphadenopathy. Patients who received intravenous contrast did not have evidence of visceral pleural abnormalities or underlying pulmonary parenchymal disease. CONCLUSION: Forty-one percent of the patients with lymphoma and pleural effusions had CT evidence of pleural and/or extrapleural disease. The majority of the patients with extrapleural disease had adjacent posterior mediastinal disease.

Transthoracic needle aspiration biopsy: variables that affect risk of pneumothorax.

PURPOSE: To analyze the influence of multiple variables on the rate of pneumothorax and chest tube placement associated with transthoracic needle aspiration biopsy of the lung. MATERIALS AND METHODS: In 346 patients, 331 computed tomographically (CT) guided and 24 fluoroscopically guided lung biopsies were performed. Variables analyzed were lesion size, depth, and location; number of pleural passes; needle size; presence of emphysema; and training level of the person who performed the biopsy. RESULTS: Pneumothorax occurred at 144 (40.4%) of 356 biopsies, including 139 (42.0%) CT-guided and five (21%) fluoroscopically guided biopsies. Chest tube placement was needed in 25 (17.4%) of 144 cases of pneumothorax (7% of all biopsies). An increased rate of pneumothorax was correlated with smaller lesion size (P = .001) and presence of emphysema (P = .01). Patients with emphysema were three times as likely to require chest tube placement. The pneumothorax rate was 15% (16 of 105) if no aerated lung was traversed and approximately 50% if aerated lung was penetrated. Lesion location, needle size, number of pleural passes, and level of training were not correlated with pneumothorax rate. CONCLUSION: Smaller lesion size and emphysema are strongly correlated with occurrence of pneumothorax. Pneumothorax was more than three times less frequent if no aerated lung was traversed. After pneumothorax, chest tube placements were related to the presence of emphysema.

Virtual bronchoscopy.

Three-dimensional endoluminal tracheobronchial simulations can be derived successfully from thoracic helical CT scans, and can reproduce the appearances of major endobronchial abnormalities confirmed during FB. The prospects of ever-faster CT scanners (capable of submillimeter resolution) merged with greater computer power make it likely that current versions of virtual bronchoscopy images will seem primitive in the future. Initial descriptive reports suggest great potential, but the startling visual appeal of these 3-D portrayals of a patient's airway and mediastinal anatomy and the prospects of exploring this information in real time do not establish its clinical role. Such virtual bronchoscopy findings are generally predictable on the basis of currently available axial CT images alone. The extent to which these 3-D endobronchial renderings improve the already high predictive values of CT requires critical study. In their patients with lung cancer Cicero et al observed that neither the staging nor diagnosis was modified substantially, but virtual bronchoscopy contributed to enhanced understanding of the pathology of the neoplastic process. Whether this added perspective translates to tangible benefits for patients is an intriguing possibility that has yet to be proved. The unique 3-D endobronchial view may offer particular advantages in some individuals and contribute to the patient's noninvasive evaluation. Because of the already high yield of conventional CT, diagnostic yield alone is not likely to be the sole best measure of this evolving technology. Accordingly, future multidisciplinary research investigations will also need to prospectively address nuances of decision-making and measure appropriate patient outcomes. In these efforts the active dialogue between chest clinician and radiologist will remain essential to defining and realizing the true potential of virtual bronchoscopy.

Herpes simplex virus 1 pneumonia: patterns on CT scans and conventional chest radiographs.

PURPOSE: The goal of our study was to describe the herpes simplex virus type 1 (HSV 1) pneumonia patterns on CT scans and chest radiographs. METHOD: We retrospectively reviewed clinical records and chest radiographs of 24 patients with HSV 1 pneumonia and 10 with pneumonia from combined HSV and mixed flora infection. We also reviewed CT scans available for eight patients with HSV pneumonia and four with mixed pneumonia. RESULTS: CT scans of eight patients with HSV pneumonia demonstrated multifocal segmental and subsegmental ground-glass opacities (n = 8), additional focal areas of consolidation (n = 6), scattered distribution (n = 6), and pleural effusions (n = 7). Chest radiographs (23 patients) showed patchy segmental and subsegmental ground-glass opacities and consolidation (n = 23), scattered distribution (n = 20), and pleural effusions (n = 12). Radiographic patterns for isolated HSV pneumonia and mixed flora pneumonia were not significantly different. CONCLUSION: With a growing population of at-risk immunosuppressed patients, it is important to recognize CT and chest radiography patterns consistent with, although nonspecific for, HSV 1 pneumonia.

Distinction of consolidative bronchioloalveolar carcinoma from pneumonia: do CT criteria work?

OBJECTIVE: The purpose of this study was to compare the CT findings of consolidative bronchioloalveolar carcinoma (BAC) with consolidative infectious pneumonia and determine if any pattern revealed by CT is more specific for one disease than the other and may therefore expedite a diagnosis of consolidative BAC using CT. MATERIALS AND METHODS: The CT findings in 20 patients with consolidative BAC and 20 patients with consolidative infectious pneumonia were reviewed. Radiologic features included the presence and distribution of consolidation, nodules, and ground-glass opacities; the presence of air bronchogram, mucous bronchogram, contrast enhancement, cysts, or cavities within the consolidation; and pulmonary fibrosis or significant parenchyma scarring. RESULTS: Statistically significant (p < .003) findings that were more often seen on CT scans of patients with consolidative BAC than on those of patients with consolidative pneumonia included coexisting nodules (p < .001) and a peripheral distribution of consolidation (p < .001). CONCLUSION: When nonresolving peripheral consolidative pneumonia, especially with associated nodules, is shown on CT, radiologists should suspect BAC when the patient is an adult with normal immunity.

Fiberoptic bronchoscopy in coronary care unit patients: indications, safety, and clinical implications.

STUDY OBJECTIVES: To evaluate the indications, safety, therapeutic impact, and outcome of fiberoptic bronchoscopy (FOB) in coronary care unit (CCU) patients. DESIGN: Retrospective review of all CCU patients undergoing FOB during a 6-year period. SETTING: Tertiary care university hospital. RESULTS: Among 8,330 patients admitted to the CCU; 40 (0.5%) patients underwent FOB to evaluate pulmonary abnormalities, most often (78%) to appraise clinically suspected pneumonia. Thirty-five (88%) patients were intubated and 21 (53%) had acute myocardial infarction (MI) before FOB. There were two major complications (bleeding, intubation) occurring within 24 h of FOB, one of which appeared due to the procedure. No episodes of chest pain or ischemic events were recorded and no significant increase in major complications was noted in MI patients (3% vs 5%). Patients having FOB within 10 days of MI had higher survival (79%) than those undergoing FOB later (29%) (p = 0.05). Seven different bacterial pathogens were isolated in 6 (15%) patients, probably reflecting prior empiric antibiotics in 32 (80%) patients. Therapy was changed in 64% of patients in whom a potential pathogen was identified. Despite alterations in treatment, patients with clinically suspected pneumonia and any organisms isolated by FOB had greater mortality (79% vs 31%, p = 0.003) than those with sterile FOB cultures. CONCLUSION: FOB may be diagnostically useful in the evaluation of pulmonary abnormalities in selected patients with acute cardiac disease, can be performed safely, and may influence management decisions. Positive bronchoscopy cultures often influence therapy but are associated with higher mortality, suggesting a lethal effect of nosocomial pneumonia in this subset of CCU patients. The risks of FOB must be weighed with the impact of FOB results on patient outcome, and its role requires further investigation.

Bronchogenic carcinoma: a survey of CT protocols for staging disease.

RATIONALE AND OBJECTIVES: To determine whether a standard computed tomographic (CT) protocol is used in the staging of lung cancer. MATERIALS AND METHODS: A questionnaire was designed to determine what type of CT scanner is used, whether intravenous contrast material is used, how often the abdomen is scanned and at what level, and the section thicknesses used in scanning the chest and abdomen in patients with lung cancer. A total of 1,118 survey forms were mailed to members of the Society of Thoracic Radiology and to all community hospitals in the United States with at least 300 beds. RESULTS: The authors received 520 responses (47%) to the 1,118 questionnaires mailed. Of these 520 responses, 140 were from society members, 256 were from hospitals with 300-500 beds, and 124 were from hospitals with more than 500 beds. One-half of hospital respondents used helical CT scanners. Significantly more society members used helical CT scanners (P < .001). Intravenous contrast material was used to opacify mediastinal blood vessels at 449 (86%) of 520 hospitals. Intravenous contrast material was used for liver scanning at 363 (82%) of 444 hospitals, but it was used less often at hospitals in the northeast region and by society members than at hospitals in other regions (P < .001). A mixture of section thicknesses was commonly used (252 [48%] of 520 responses) for scanning the chest; a thickness of 8-10 mm was used in scanning the abdomen at most hospitals (348 [78%] of 445 responses). CONCLUSION: No CT protocol is consistently used for the examination of patients with lung cancer. Use of intravenous contrast material during chest or liver CT also is not uniform.

Pulmonary artery sarcomas: a review of clinical and radiologic features.

Primary pulmonary artery sarcomas are rare tumors that are frequently misdiagnosed as chronic pulmonary emboli. We present classic imaging findings and review data from 136 previously reported sarcomas. We believe that the imaging findings can be quite specific, especially when the disease is advanced. Despite a recent increase in antemortem diagnosis, the prognosis remains poor. Surgery prolongs survival time and is potentially curative. Experience with adjuvant chemotherapy and radiotherapy is limited.

Tree-in-bud pattern: frequency and significance on thin section CT.

PURPOSE: Our goal was to describe those diseases of the airways that manifest the tree-in-bud (TIB) pattern on CT scan and to establish a differential diagnosis for this CT scan finding. METHOD: We prospectively collected cases with the TIB pattern on CT and reviewed the scans of patients with histories pertaining to small airway disease. CT scans were performed at 1 to 3 mm collimation. RESULTS: Twenty-six of 27 cases with the TIB pattern had associated bronchiectasis or proximal airway wall thickening. One case with normal proximal airways had an acute aspiration. In addition, we reviewed 141 scans of patients with emphysema, respiratory bronchiolitis (RB), bronchiolitis obliterans (BO), bronchiolitis obliterans organizing pneumonia (BOOP), extrinsic allergic alveolitis (EAA), bronchiectasis, bronchitis, and pneumonia. Of the CT scans with bronchiectasis, 25.6% had TIB, and 17.6% of CT scans with acute infectious bronchitis or pneumonia had this pattern. None of the patients with emphysema, BO, BOOP, EAA, or RB had this pattern. CONCLUSION: The TIB pattern on CT scan is mostly associated with pulmonary infections that commonly involve the large airways. This pattern was present in 17.6% of cases with acute bronchitis or pneumonia and 25.6% of cases with bronchiectasis.

Chronic pulmonary disorders in sickle cell disease: findings at thin-section CT.

PURPOSE: To characterize the non-acute abnormalities seen at computed tomography (CT) in patients with sickle cell (SC) disease and a prior history of acute chest syndrome (ACS)-pneumonia. MATERIALS AND METHODS: Twenty-nine patients with SC disease who had experienced one to more than 10 (median, six) previous episodes of ACS-pneumonia were prospectively studied with thin-section CT of the thorax. Scans were graded for interstitial disease and assigned a disease index ranging from 0 to 3. Twenty-four patients underwent pulmonary function tests (PFTs) and measurement of their blood gasses. RESULTS: Twelve of the 29 patients (41%) had significant interstitial disease that was multifocal. A correlation was found between the disease index and number of episodes of ACS-pneumonia (P = .02) but not between the disease index and PFT results. CONCLUSION: Thin-section CT demonstrates significant multifocal interstitial lung abnormalities in 41% of selected patients with SC disease. The pattern is most consistent with scarring from episodes of infarction or infection.