Isotropic chest CT examination: diagnostic quality of reformats.

AIM: To evaluate the image quality of axial and coronal reformats obtained from isotropic resolution 40-channel chest computed tomography (CT) examinations. METHODS AND MATERIALS: Thirty consecutive patients with intravenous contrast-enhanced chest CT examinations using a 40-channel CT machine were enrolled for the study. The raw data were reconstructed into two sets of source axial images: 0.9 mm section width and 0.45 mm reconstruction interval (isotropic resolution) and 4mm section width with 3 mm reconstruction interval (anisotropic resolution; group A). The isotropic data set was reformatted into axial and coronal stacks (groups B and C, respectively) with 4 mm section width and 3 mm interval. Three independent readers evaluated stacks A to C using a three-point scale for resolution of right lower lobe segmental bronchi, edge sharpness of major and minor fissures, respiratory motion artefact, reconstruction artefact, noise and overall image quality. RESULTS: The sharpness of fissures scored significantly higher with the coronal reformats (group C) compared with the axial image sets (groups A and B) (p<0.01). Noise in group A scored significantly lower than groups B or C (p<0.01). For other parameters there was no statistical difference between the groups. There was substantial or excellent agreement between the reviewers. CONCLUSION: Isotropic imaging of the chest allows creation of reformats with similar image quality as similar thickness axial source images. These reformats are probably of sufficient quality to form the basis of clinical interpretation.

Reliability of soft-copy versus hard-copy interpretation of emergency department radiographs: a prototype study.

OBJECTIVE: The purpose of this study was to compare the diagnostic reliability of hard-copy and soft-copy interpretation of radiographs obtained in the emergency department using a methodology for evaluating imaging systems when independent proof of the diagnosis is not available. MATERIALS AND METHODS: We collected radiographs from a stratified sample of 100 patients seen in the emergency department. The images were obtained using computed radiography, and the digital images were printed on film and stored for display on a workstation. A group of seven experienced radiologists reported the cases using both film and the workstation display. The results were analyzed using mixture distribution analysis (MDA). RESULTS: The reliability expressed as the percentage of agreement of a typical observer relative to the majority was computed from the MDA. The result was 90% for both hard copy and soft copy with bootstrap confidence intervals of 86-94%. CONCLUSION: We conclude that, in the emergency department, soft-copy interpretation is as reliable as hard-copy interpretation. The strength of this conclusion depends on the validity of the MDA approach as well as the extent to which the observer sample and case sample are representative of the emergency department.

Stereotactic localization of breast lesions: how it works and methods to improve accuracy.

A computer simulation of stereotactic breast biopsy was developed that paralleled the geometric configuration of a currently available breast biopsy system. This model was developed to define and improve the targeting of breast lesions with stereotactic biopsy techniques. Lesions must be clearly identified and accurately targeted on both views for successful localization. Nonvisualization of a lesion may result from overlying tissue or from the geometric configuration of the imaging system. Familiarity with the geometric configuration of the biopsy unit, especially the location of the reference point and center of rotation, facilitates understanding of apparent changes in lesion position (parallax shift). Inaccuracy in lesion targeting on one or both views will manifest predominantly as an error in the calculated z value (depth). The magnitude and direction of this error are largely determined by the direction of the targeting error. Compensatory strategies include use of a long-throw core biopsy gun or directional vacuum-assisted biopsy device and additional sampling along the z axis and should be accompanied by critical evaluation of both pre- and postfire images. Understanding geometric considerations as well as how targeting accuracy affects accuracy in lesion localization should lead to greater success in sampling even challenging breast lesions at stereotactic biopsy.

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.

Radiographic assessment of hyperinflation: correlation with objective chest radiographic measurements and mechanical ventilator parameters.

BACKGROUND: Pulmonary barotrauma is a potentially fatal complication of positive pressure ventilation. We previously found that barotrauma occurred in patients with radiographic hyperinflation, but few objective data define the relationships among hyperinflation, objective chest radiograph (CXR) measurements, ventilator parameters, and development of barotrauma. OBJECTIVES: We sought (1) to assess the relationships among hyperinflation, objective CXR findings, mechanical ventilator parameters, and development of barotrauma. (2) To compare radiographic hyperinflation, ventilator parameters, and incidence of barotrauma in a current group of ICU patients with historical control subjects. SETTING: Medical and surgical ICU patients in a university hospital. DESIGN: Prospective blinded observational study; comparison of current series with historical control subjects. METHODS: One hundred two prospectively enrolled mechanically ventilated medical and surgical ICU patients each received portable supine CXRs that were reviewed independently by three radiologists who made objective measurements and subjectively determined the likelihood of hyperinflation. Ventilator parameters were recorded at the bedside at the time each CXR was obtained. CXR measurements and ventilator parameters were then related to the development of barotrauma during the course of ventilation and compared with findings of a prospective study at our institution 1 year earlier. RESULTS: Radiographically recognizable hyperinflation occurred in 18 of 102 mechanically ventilated ICU patients (18%) and correlated with lung length (24.7 vs 19.8 cm; p<0.05) and the anterior rib number that intersects the hemidiaphragm (5.4 vs 4.7; p<0.05). Patients with hyperinflation were ventilated at higher tidal volume per kilogram (VT/kg) (11.0 vs 9.4; p=0.0081), but peak airway pressure, plateau pressure, and positive end-expiratory pressure were similar. There were significant decreases in VT (810 vs 739 mL; p=0.015) and VT/kg (11.0 vs 10.1 mL/kg; p<0.001) in these mechanically ventilated ICU patients in comparison to hospital control subjects evaluated during the previous year. Paralleling these changes was a decrease in the frequency of CXR hyperinflation (p=0.003) and the incidence of ventilator-associated barotrauma (6.5% vs 0.98%; p=0.048). CONCLUSIONS: Ventilation at higher VT/kg is associated with a higher incidence of CXR hyperinflation. Radiographic hyperinflation is associated with lung length > or =24.7 cm and visualization of the sixth anterior rib. Patients with hyperinflation may be at greater risk for developing barotrauma or volutrauma. Ventilatory strategies utilizing lower volumes are associated with a lower incidence of such trauma in the current sample as compared with historical control subjects.

Epithelioid hemangioendothelioma of the superior vena cava: computed tomography demonstration and review of the literature.

A case is reported of a 79-year-old man with rapid onset of superior vena cava syndrome caused by an epithelioid hemangioendothelioma. Contrast-enhanced helical computed tomography showed a soft-tissue mass with punctate calcifications obstructing the superior vena cava and infiltrating adjacent fat. Epithelioid hemangioendothelioma is a very rare primary mesenchymal tumor of the superior vena cava that often presents with calcifications. It should to be added to the differential diagnosis of tumors of the anterior mediastinum.

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.

Thoracic complications in patients undergoing intraperitoneal heated chemotherapy with mitomycin following cytoreductive surgery.

BACKGROUND: The purpose of this study was to determine the incidence and severity of thoracic reactions in patients undergoing intraperitoneal heated chemotherapy (IPHC). METHODS: Forty-two patients who had intraperitoneal disseminated malignancies were treated with cytoreductive surgery (CS) and IPHC. The primary malignancies included carcinoma of the colon (n = 17), stomach (n = 6), appendix (n = 6), pseudomyxoma peritonei (n = 3), mesothelium (n = 2), ovaries (n = 2), jejunum (n = 2), gallbladder (n = 1), urachus (n = 1), and peritoneal carcinomatosis (n = 2). After CS, IPHC with mitomycin (MMC) was administered by perfusion at 40.5 degrees C. After IPHC, multiple radiographs of the chest were reviewed in comparison to the control group. RESULTS: Thoracic complications occurred in 36 patients (86%), including atelectasis in 32 patients (76%), pleural effusions in 27 (64%), pulmonary edema in 10 (24%), pneumonia in 2 (5%), and pneumothorax in 2 (5%). The incidence of thoracic complications in the IPHC group was significantly higher than that of patients in the control group (P < .05). Correlations between the prevalence of pleural effusion and the dose of MMC, duration of procedure, and presence of thrombocytopenia were not significant (P > .05). CONCLUSIONS: Bibasilar atelectasis and pleural effusions are common findings after IPHC with MMC, but most of them do not necessarily warrant intervention.

Localized benign fibrous tumors of the pleura: MR appearance.

PURPOSE: Our goal is to describe the MR findings in benign localized fibrous tumors of the pleura. METHOD: Chest radiographs, CT scans, and MR images of four patients with localized benign fibrous tumors of the pleura were retrospectively reviewed and correlated with the pathologic findings. RESULTS: Tumors ranged from 4 to 18 cm in their largest diameter. Three tumors were located in the diaphragmatic region, and one was within the left major fissure. All tumors were round to ovoid, pedunculated, and well delineated. On T1-weighted SE MR images, tumors showed low signal intensity. All tumors had heterogeneous but predominantly low signal intensity on proton-density-weighted images and lower signal intensity on T2-weighted images. CONCLUSION: Localized benign fibrous tumors of the pleura were characterized by low signal intensity on all MR sequences that is explained by high collagen content within the tumors' stroma and should suggest the diagnosis preoperatively.

Case report. Aortic pseudoaneurysm with aortobronchial fistula: diagnosis with CT angiography.

We report the case of an 82-year-old man with a 12-month history of recurrent hemoptysis caused by an aortobronchial fistula. Twenty-five years earlier, the patient underwent placement of an aortic graft for aortic transection sustained in a motor vehicle accident. Chest radiography and bronchoscopy showed nonspecific abnormalities. We emphasize the role of CT angiography with 2D and 3D reconstructions for the diagnosis of and surgical planning for this rare but potentially lethal aortic postoperative complication.

Chest X-ray changes in air space disease are associated with parameters of mechanical ventilation in ICU patients.

To assess relationships between parameters of mechanical ventilation (MV) and portable chest X-ray (CXR) measurements of lung length (LL) and severity of air space disease, a prospective, randomized, blinded comparison of 102 adults in a university hospital was performed. Each patient received two portable, supine CXRs on different MV breaths within 5 min of one another. Ventilator parameters were recorded. All 204 CXRs were randomly assorted and read independently by three radiologists. Air space disease was considered more severe with pressure support ventilation (PSV) breaths than with intermittent mandatory ventilation (IMV) breaths (p = 0.0003), and its extent correlated inversely with static compliance (p = 0.0001, r = -0.40). Among patients having CXRs on both IMV and PSV breaths, 15 of 67 (22%) had their overall degree of air space disease read differently by one category (mild, moderate, or severe). Increases in LL between the two CXRs were associated with increasing peak (p = 0.0038) or mean (p = 0.0065) airway pressure, tidal volume (VT) (p = 0.022), and VT per kilogram (p = 0.006). We conclude that lung volume changes during MV, typically not noted nor controlled for during portable chest radiography, may substantially alter the interpretation of air space disease and LL. Physicians monitoring intensive care unit (ICU) patients with daily CXRs should be aware of the variables influencing interpretation of portable CXRs of ICU patients.

Case report. Chemical-shift MRI of exogenous lipoid pneumonia.

Exogenous lipoid pneumonia results from the aspiration or inhalation of fatty substances, such as mineral oil found in laxatives or nasal medications containing liquid paraffin. We present standard and lipid-sensitive (Chemical-shift) MR findings in a patient with histologically confirmed lipoid pneumonia. The loss of signal intensity in an area of airspace disease on opposed-phase imaging was considered specific for the presence of lipid.

Virtual bronchoscopy. Relationships of virtual reality endobronchial simulations to actual bronchoscopic findings.

Advances in computer technology have permitted development of virtual reality images of the tracheobronchial tree using data sets derived from helical CT of the chest. To determine the relevance of these images to actual bronchoscopic findings, we compared "virtual bronchoscopy" images with videotaped bronchoscopy results in 20 patients who had undergone both helical chest CT and fiberoptic bronchoscopy during clinical evaluation of their thoracic problems. Suboptimal endobronchial simulations in ten patients identified important, readily-addressed technical requirements for this imaging procedure. In the ten patients with technically suitable renderings of the airway, virtual bronchoscopy simulations accurately demonstrated endobronchial obstructions by tumor in five, airway distortion and/or ectasia in four, and accessory bronchi in another. These preliminary observations suggest that virtual bronchoscopy simulations accurately represent major endobronchial anatomic findings. This technique may have a role in prebronchoscopy planning, endoscopy training, and/or endobronchial therapy, and merits further study.

Aspiration in patients in critical care units.

Pulmonary aspiration is a serious cause of morbidity and mortality in patients with a depressed sensorium, patients with neuromuscular discoordination, or patients having a structural disorder of the upper aerodigestive tract. This problem is relatively frequent in patients in critical care units and other areas where anesthesia is used. The most common manifestations of pulmonary aspiration are chemical pneumonitis, pleuropulmonary infection, and acute airway obstruction. The clinical and radiographic manifestations of pulmonary aspiration are nonspecific and diagnosis depends on a consistent constellation of clinical and radiographic criteria.

Mediastinal staging of non-small-cell lung cancer with positron emission tomography.

To determine the usefulness of positron emission tomography with fluoro-2-deoxyglucose (PET-FDG) in assessing mediastinal disease in patients with non-small-cell lung cancer (NSCLC) and to compare its yield to that of computed tomography (CT), we performed a prospective consecutive sample investigation in a university hospital and its related clinics. In 30 patients with NSCLC with clinical stage I (T1-2, NO, MO) disease, we compared the results of chest CT and PET-FDG with the findings at surgical exploration of the mediastinum. Seven (77%) of nine patients with surgically proven mediastinal metastasis were identified by the PET-FDG results, with four false-positives in 21 patients with negative lymph node dissections (p = 0.004). Using the results of pathologic examination of mediastinal lymph nodes as the criterion standard, the diagnostic sensitivity, specificity, accuracy, positive predictive value (PPV), and negative predictive value (NPV) for PET-FDG imaging of mediastinal metastases were 78%, 81%, 80%, 64%, and 89%, respectively. The sensitivity, specificity, accuracy, PPV, and NPV for chest CT in the detection of mediastinal metastasis were 56%, 86%, 77%, 63%, and 87%, respectively. CT and PET-FDG results agreed in 21 patients. The diagnostic accuracy of the combined imaging modalities was 90%. We concluded that mediastinal uptake of FDG correlates with the extent of mediastinal involvement of NSCLC and may contribute to preoperative staging. PET-FDG imaging complements chest CT in the noninvasive evaluation of NSCLC, and strategies for its use merit further investigation.

Systems integration: requirements for a fully functioning electronic radiology department.

Disparate computer-based information systems such as hospital information systems (HIS), radiology information systems (RIS), and picture archiving and communication systems (PACS) have been introduced into radiology departments at various times to meet specific operational objectives. Typically, these systems are implemented without an integration strategy. Systems integration, which optimizes integrity of data and labor savings, can be achieved by two general approaches. The first links the HIS to the PACS; the second involves interlinking of the HIS, RIS, and PACS, with the RIS as the central controlling system. Standardization in hardware, operating systems, and data base formats--which will allow true integration--is being addressed nationally and worldwide. Operational issues to resolve include ways to increase network capacity, control of data flow, and strategies for dealing with downtime. In the future, systems integration will enable prefetching, two-way interfaces, interfaces with digital dictation systems, and improved linkages with external digital input devices.

Evaluation of PACS in ultrasonography.

We review our experience with a picture archiving and communication system to replace film in the ultrasound section of a clinical radiology department. The system includes three ultrasound units connected by a fiberoptic network via acquisition nodes to a central data management system, workstation, and optical jukebox. The system handles 80% of sonographic studies in the department. Image production, interpretation, storage, and retrieval are evaluated. Despite limitations, a picture archiving and communication system can be integrated into a functioning ultrasound section of an active radiology department with minimal disruption and promising results.

Plain and computed radiography for detecting experimentally induced pneumothorax in cadavers: implications for detection in patients.

Pneumothorax was induced in cadavers to determine the effects of patient positioning and imaging modality (conventional screen-film and computed radiography) on radiographic findings. Chest radiography, with cadavers in the supine frontal, erect frontal, and left lateral decubitus positions, was performed at baseline and after injection of incremental quantities of air into the pleural space. Five radiologists independently interpreted each radiograph. The ability of the radiologists to diagnose pneumothorax varied by cadaver position and depended on volume of air. Overall, the left lateral decubitus view was most sensitive (88%) for diagnosis of pneumothorax, followed by the erect (59%) and supine (37%) views. Receiver operating characteristic curves and multiple repeated measures analysis of variance revealed no statistically significant difference between diagnostic proficiency with conventional screen-film radiography and that with computed radiography. The authors conclude that the lateral decubitus view is superior to the erect and supine views for pneumothorax detection and that conventional and computed radiography perform similarly in pneumothorax detection.