Evaluation of competence in the interpretation of chest radiographs.

RATIONALE AND OBJECTIVES: The purpose of this study was to determine relative rates of missed diagnoses for radiologists as a measure of competence in interpreting chest radiographs. MATERIALS AND METHODS: Cases involving differing interpretations of chest radiographs were collected from January 1994 through December 1999 by faculty (chest and nonchest radiology specialists) in an academic radiology department. A quarterly peer-review process designated cases months after the fact, and anonymously, as no miss or as class I (nondiagnosable), class II (very difficult diagnosis), class III (should be diagnosed most of time), or class IV (should almost always be diagnosed) missed diagnoses. The rates and classes of missed diagnoses were compared among chest faculty and for the nonchest radiology specialists as a group. RESULTS: Chest radiologists read 184,977 studies, and nonchest radiologists read 300,684 studies. Of these, 243 missed diagnoses were classified (classes I and II, 184 cases; class III, 50; and class IV, nine). No difference was detected in the rate of class III and IV misses among chest faculty, but nonchest faculty had significantly more class III (P = .022) and class IV misses (P = .016). CONCLUSION: Random sampling of differing interpretations can yield a relative rate of missed diagnoses for radiologists. No difference was detected in clinically important misses (ie, classes III and IV) among chest radiologists, but a statistically significantly higher rate of seemingly obvious misdiagnoses was found for nonchest specialty radiologists. Potential biases may have influenced this analysis, including disease prevalence, sampling, clinical factors, observer variability, and truth-in-diagnosis.

Continuous quality improvement process to track lost radiographs and reduce losses.

OBJECTIVE: To describe a quality improvement process that was initiated in a Department of Radiology to reduce the number of incomplete or "lost" imaging studies and decrease the time from the initiation of an imaging study to printing of the final report. METHODS: Incomplete cases were defined as those imaging studies that did not have a signed final report more than 3 days and less than 90 days after imaging. A computer program was written to generate a monthly incomplete case list from the radiology information system database; each step in the process, from patient arrival to final report printing, was analyzed and a list of root causes (for the incomplete cases) was developed. Short- and long-term interventions were introduced and the effects were monitored from 1992-1999. RESULTS: Problems were identified at each step in the process. Although some of the root causes originated outside the authority of the Department of Radiology, interventions we implemented within the department reduced the incomplete list by 72%, from a high of 2.8% of all imaging examinations to less than 0.8%. Continual monitoring of the problem is necessary to maintain this level. CONCLUSION: The number of incomplete or "lost" imaging studies can be decreased using a continuous quality improvement process. This leads to improved patient care and increased revenue.

Bedside chest radiography as part of a postcardiac surgery critical care pathway: a means of decreasing utilization without adverse clinical impact.

OBJECTIVE: To evaluate the use of bedside chest radiography and patient outcome before and after implementation of a cardiac surgery critical care pathway that included guidelines for bedside radiography. DESIGN: A cohort observational study. SETTING: A university hospital in the midwest. PATIENTS: Three groups, of 100 patients each, undergoing cardiac surgery in 1990, 1991, and 1995. INTERVENTION: Introduction of a critical care pathway. MEASUREMENTS: Medical records were retrospectively reviewed in three groups of 100 patients each: before the introduction of the critical care pathway; 2 months after introduction of the pathway in 1991; and 4 yrs after introduction in 1995. Data were analyzed to determine operative risk for each group. Subsequent analyses determined bedside radiography use, total length of hospital stay, and patient outcome (mortality rate, complications requiring intervention, and reoperation) during hospitalization and at outpatient follow-up 15-30 days postdischarge. RESULTS: Total length of hospital stay was shorter for the 1995 group (7.6+/-6.6 days) compared with other groups (prepathway, 11.1+/-10.3 days; 1991 postpathway, 10.2+/-9.6 days; p<.05). The mean numbers of radiographs per patient were as follows: prepathway, 5.1; 1991 postpathway, 5.2; and 1995 postpathway, 3.3. The mean number of radiographs in the 1995 group was significantly lower (p = .02). More patients had the proposed number of two bedside radiographs described in the pathway in the 1995 group compared with the other groups (prepathway, p<.0001; the two-month postpathway group, p = .01). Twenty-three malpositioned catheters/tubes were found in the prepathway and 1991 groups compared with 11 in the 1995 group (p = .02). No statistically significant difference was found in inpatient complications (mediastinal bleeding, pneumothoraces, and pleural effusions), postdischarge complications, reoperations, or mortality rate. CONCLUSION: Introduction of a critical care pathway can decrease the use of bedside radiography without adversely affecting near-term patient outcomes.

Diagnosis of pulmonary embolism: comparison of CT angiography and MR angiography in canines.

PURPOSE: To compare the sensitivity and specificity of helical computed tomographic angiography (CTA), CTA with multiplanar reconstructions (MPR)/three-dimensional-shaded surface display (3D-SSD), and gadolinium-enhanced magnetic resonance angiography (MRA) for pulmonary embolism (PE) detection. MATERIALS AND METHODS: Gelatin sponge emboli were introduced into the femoral veins of seven dogs and conventional digital subtraction angiography (CA), CTA, and MRA performed. Images from CTA, CTA with MPR/3D-SSD, and MRA were reviewed for the presence of PE in lobar and segmental arteries, and subsegmental zones. Postmortem angiography and CA were the gold standard. RESULTS: There were 50 emboli in the 294 vessels/zones analyzed. The sensitivity of CTA for the two readers was 76% (95% confidence interval [CI]; 64%-88%) and 64% (95% CI; 50%-78%), and for the two MRA readers was 52% (95% CI; 38%-66%) and 48% (95% CI; 34%-62%). CTA was more sensitive than MRA when PE were subdivided by vessel caliber. Specificity was high for CTA and MRA among all readers (98.8%-99.6%). MPR/3D-SSD did not improve results of axial CT. MRA perfusion defects were 46% and 47% sensitive and 100% specific. Interobserver agreement was high for CTA and MRA (kappa 0.92 and 0.93, respectively). The average diameter of vessels with emboli was 3.7 mm +/- 1.06. CONCLUSION: Helical CTA is more sensitive than three-dimensional gadolinium-enhanced MRA for the detection of PE. Both CTA and MRA are highly specific for PE detection and demonstrate high interobserver agreement. MPR/3D-SSD did not increase CTA performance over axial images alone.

Decision-making in radiotherapy for the cancer patient: the American College of Radiology Appropriateness Criteria Project.

The American College of Radiology Task Force on Appropriateness Criteria was developed in 1993 with the major objective of creating the most credible patient care guidelines possible. Oncology-related clinical conditions addressed by the Task Force pertain to the diagnosis of suspected disease and, after disease is diagnosed, its staging, treatment, and follow-up to determine the effectiveness of therapy.

Idiopathic pulmonary fibrosis: predicting response to therapy and survival.

Idiopathic pulmonary fibrosis (IPF) is associated with significant morbidity and mortality despite aggressive therapy. Thirty-eight patients with biopsy-proven IPF were studied to identify pretreatment features that could be used to predict short-term improvement in pulmonary function and improved longer term survival. In all patients, a pretreatment clinical (dyspnea), radiographic (chest radiograph), and physiologic (pulmonary function including exercise saturation) score was generated (CRP). A high-resolution CT scan (HRCT) was independently scored by four radiologists for ground glass (CT-alv) and linear opacity (CT-fib) on a scale of 0-4. Open lung biopsy samples were scored for cellular infiltration, interstitial fibrosis, desquamation, and granulation by an experienced pulmonary pathologist. All patients were treated with 3 mo of high-dose steroids and the CRP scoring repeated. Patients were divided into three groups: responders with a greater than 10-point drop in CRP (n = 10); stable with +/- 10 point change in CRP (n = 14); and nonresponders with > 10 point rise in CRP or death (n = 14). Those responding to steroids were treated for 18 mo in a tapering fashion. In all others, steroids were tapered quickly and oral cyclophosphamide prescribed. Responders (10 of 38) had a lower age (45.1+/-4.3 yr) than nonresponders (61.4+/-3.5 yr) or those remaining stable (53.1+/-3.3 yr) (p = 0.01). Pretreatment CRP was higher in responders (58.8+/-5.6) than nonresponders (40.5+/-4.7) or stable individuals (37.6+/-4.7) (p = 0.01). Cellular infiltration score of the open lung biopsies was higher in responders (7.6+/-0.6) than stable individuals (5.7+/-0.5) (p = 0.04). The CT-alv scores were higher and CT-fib scores were lower in responders than nonresponders. Receiver operating curve (ROC) analysis was employed to identify pretreatment features of longer term survival (follow-up of 29.1+/-2.3 mo). Only CT-fib (p = 0.009) and pathology fibrosis score (p = 0.03) were able to predict mortality. A pretreatment CT-fib score > or = 2.0 demonstrated 80% sensitivity and 85% specificity in predicting survival. Those patients who did not respond to initial steroid therapy demonstrated a worse long-term survival and greater likelihood of decreased pulmonary function. We demonstrate that pretherapy pulmonary function, pathologic and radiographic parameters are different in individuals who respond to initial prednisone therapy. Only HRCT imaging and pathologic fibrosis were able to reliably predict long-term survival in patients with biopsy-proven IPF.

Variability in the detection of enlarged mediastinal lymph nodes in staging lung cancer: a comparison of contrast-enhanced and unenhanced CT.

OBJECTIVE: Because CT protocols for staging lung cancer vary and little information exists regarding the diagnostic importance of using i.v. contrast material, our intent was to evaluate intra- and interobserver agreement in the detection of enlarged mediastinal lymph nodes, comparing i.v. contrast-enhanced and unenhanced CT. SUBJECTS AND METHODS: Fifty patients with known or suspected bronchogenic carcinoma underwent unenhanced thoracic CT followed by contrast-enhanced CT. Three observers noted enlarged lymph nodes (> 10 mm in the short axis) and assigned the enlarged nodes to American Thoracic Society nodal station designations. Enlarged lymph nodes were grouped two ways: by assigning the exact number of enlarged lymph nodes found (zero, one, two, three, four or more), and by assigning whether at least one, or no, enlarged mediastinal lymph nodes were found at a station ("one or none"). Agreement levels were determined for inter- and intraobserver interpretations using weighted kappa statistics and the McNemar test. RESULTS: The number of enlarged lymph nodes with enhanced CT was 11% higher than on unenhanced studies (418 versus 377; p = .044). Numbers of enlarged lymph nodes were different for five stations; however, the numbers were small except for the right upper paratracheal station (2R) (contrast-enhanced, 68 enlarged lymph nodes; unenhanced, 44 enlarged lymph nodes; p = .014). With regard to all stations together, intraobserver agreement between contrast-enhanced and unenhanced studies was almost perfect (kappa range, .85-.94), and no difference was found for any observer in the proportion of patients with at least one enlarged lymph node. Interobserver agreement was substantial or almost perfect for the total number of enlarged lymph nodes. For specific stations, the lowest kappa value was .48 at 2R. One observer reported more patients with at least one enlarged lymph node with contrast enhancement at station 2R (p = .031). Greater agreement existed between two observers at station 2R with contrast enhancement versus no enhancement (kappa = .85 versus .48; p = .02). Conclusions matched, and calculations of estimated kappa values gave similar results for determination of the specific number of enlarged lymph nodes at a station and the "one or none" category. CONCLUSION: We found high agreement for intra- and interobserver interpretations for contrast-enhanced and unenhanced CT, although contrast-enhanced CT revealed more enlarged lymph nodes, especially at station 2R.

Methods of cardiopulmonary support: a review for radiologists.

Physicians are generally aware of the use of bypass pumps during open heart surgery and of the intraaortic balloon pump in treatment of cardiogenic shock. In selected research centers, other advanced methods of cardiopulmonary support are being introduced. Some devices such as the total artificial heart fail clinical trials and disappear from use. Others, like some of the partial artificial hearts, improve outcomes and gain wider clinical use. Some devices temporarily support the circulation in patients recovering from acute circulatory collapse, whereas others provide longer-term circulatory support for patients awaiting transplantation. Permanently implanted devices provide circulatory assistance in cases of chronic, debilitating heart failure. Technology to support lung function in the setting of acute respiratory failure, allowing healing to take place, is also under study. Radiologists should be familiar with the operating principles and radiographic appearances of these emerging techniques to maintain their role as consultants to cardiopulmonary specialists.

Thin-section CT obtained at 10-mm increments versus limited three-level thin-section CT for idiopathic pulmonary fibrosis: correlation with pathologic scoring.

OBJECTIVE: The purpose of our study was to determine if three-level thin-section CT depicts idiopathic pulmonary fibrosis (IPF) pathology as accurately as CT obtained at 10-mm increments throughout the entire lungs. SUBJECTS AND METHODS: Thin-section (1.0- to 1.5-mm) images at 10-mm increments were obtained and scored prospectively in 25 consecutive patients with newly diagnosed IPF who were participating in a Special Center of Research grant for interstitial lung disease. Each patient's lobe was scored by four thoracic radiologists on a scale of 0-5 for both ground-glass attenuation and fibrosis. The radiologists used three images (limited CT) and also used the entire data set (complete CT). CT scores were compared with pathology scores from 67 open and thoracoscopic biopsies. Limited and complete scores were compared with each other (Pearson correlation coefficient). Interobserver variation in the CT scoring system was assessed using kappa values. RESULTS: CT fibrosis scores strongly correlated with pathology fibrosis scores for complete (r = .53, p = .0001) and limited (r = .50, p = .0001) CT. CT ground-glass scores correlated with the histologic inflammatory scores for each lobe on complete (r = .27, p = .03) and limited (r = .26, p = .03) CT. The desquamative subcomponent of the pathology inflammatory score had the highest correlation with the CT ground-glass scores (complete: r = .29, p = .01; limited: r = .33, p = .007). Good interobserver agreement existed for both the alveolar and fibrosis components of the CT scoring system (kappa values ranging from .51 to .83) for each lobe of the lung on limited and complete CT. CONCLUSION: Limited thin-section CT reveals the pathologic changes associated with IPF as well as CT obtained at 10-mm increments. An added advantage of limited thin-section CT is that it exposes patients to less radiation.

Extracorporeal membrane oxygenation in adults: radiographic findings and correlation of lung opacity with patient mortality.

PURPOSE: To describe the radiographic appearance of extracorporeal membrane oxygenation (ECMO) in adults and to correlate lung opacity with physiologic parameters and mortality. MATERIALS AND METHODS: Chest radiographs of 50 adults treated with ECMO were reviewed; pre-ECMO radiographs were available in 35 patients. Lung opacity was assigned a score of 0-4. Complications of ECMO seen at chest radiography were recorded. RESULTS: The lung opacity scores of the first post-ECMO radiographs were higher than those of the pre-ECMO radiographs in 17 of 35 patients (P = .0005). Maximum opacity score was significantly lower for patients who survived compared with those who died (P = .001). Twelve of 14 patients (86%) with a maximum opacity score of 4 died, compared with eight of 29 patients (28%) with a maximum score of 3. Sixteen of 26 patients (61%) with evidence of baro-trauma died, compared with six of 24 patients (25%) without pneumothorax (P = .02). Four patients developed hemothorax. CONCLUSION: Lung opacity increases immediately after initiation of ECMO. Increased opacity corresponds to decreased pulmonary function, and severe opacity correlates strongly with mortality.

Partial liquid ventilation with perflubron during extracorporeal life support in adults: radiographic appearance.

PURPOSE: To describe the radiographic appearance of perflubron-filled lungs during partial liquid ventilation (PLV). MATERIALS AND METHODS: Supine chest radiographs (391 anteroposterior, 154 lateral radiographs) were obtained before and after daily perflubron instillation in 13 adults undergoing PLV who were receiving extracorporeal life support. Perflubron distribution, barotrauma, and inability to discern catheters were evaluated. RESULTS: Immediately after instillation of perflubron, opacification of more than two-thirds of the lungs was shown in 12 of 13 patients. A gravity-dependent distribution of perflubron was shown on 146 (95%) of 154 lateral radiographs. Perflubron gradually cleared until it filled less than one-third of the lungs 6.8 days later (range, 2-20 days). In the five survivors, minimal perflubron was visible up to 138 days. In five patients, perflubron increased the visibility of small pneumothoraces present before PLV. Location of intrathoracic catheters was obscured on 44 radiographs. CONCLUSION: Perflubron symmetrically opacifies the lungs in a gravity-dependent distribution during PLV and clears to minimal levels within 3 weeks.

Implications of unsuspected pulmonary embolism detected by computed tomography.

OBJECTIVE: To describe the computed tomography (CT) findings and clinical implications of pulmonary thromboembolism noted incidentally on CT. PATIENTS AND METHODS: The authors reviewed the CT studies and medical records for nine patients in whom CT had shown clinically unsuspected pulmonary thromboembolism. The study group consisted of seven men and two women ranging in age from 51 to 75 years, who were referred for CT over a 5-year period for a variety of indications. The location of the emboli and the presence and location of parenchymal and pleural abnormalities were determined. Subsequent changes in patient care were analysed. RESULTS: The locations of the thromboemboli were described according to pulmonary zone. One case involved zone 1 (main pulmonary artery to a lung), all involved zone 2 (first-order branches), and four involved extension into zone 3 (second-order branches). No emboli were distinguished in zone 4 (beyond the segmental arteries). Four patients had pleural-based opacities characteristic of infarcts, and three had pleural effusions. Eight patients underwent confirmatory testing. A vena cava filter was placed in three patients, one of whom also received anticoagulation therapy. The other six patients were treated by anticoagulation alone. All of the patients survived and were discharged. CONCLUSION: Radiologists should watch carefully for occult pulmonary thromboembolism when interpreting CT studies of the thorax. Establishing this diagnosis can result in immediate changes to treatment and possibly a reduction in the substantial morbidity and mortality associated with untreated pulmonary emboli.

Helical computed tomography for the evaluation of tracheal stenosis.

BACKGROUND: Helical computed tomography with multiplanar reconstruction (CT/MPR) was used to study proximal airway stenosis. METHODS: Twenty-eight helical CT/MPR studies were obtained in 25 patients with known or suspected stenosis of the trachea or main bronchi. Computed tomographic results were compared with planar tomograms and bronchoscopic evaluation of the airway. RESULTS: CT/MPR accurately demonstrated the site and degree of tracheal and main bronchial stenoses with a sensitivity of 93%, a specificity of 100%, and an accuracy of 94%. There was one false negative study in a patient with tracheomalacia. In a second patient, a tracheal web was only apparent on nonstandard viewing windows. CONCLUSIONS: CT/MPR provides good anatomic detail and is an increasingly available technique. Potential drawbacks include the need for a longer breath-hold (15 to 45 seconds) and increased complexity of data compared with conventional tomograms. Helical CT/MPR is useful in the preoperative evaluation of these patients and, as experience accumulates, may replace the use of conventional tomograms.

Squamous cell carcinoma of the thymus with paraneoplastic hypercalcemia.

Primary thymic carcinoma is a rare neoplasm that in contradistinction to thymoma, is not supposed to be associated with a paraneoplastic syndrome. A 73-year-old man, with new onset of disorientation, was found to have an elevated serum calcium level as the cause. Computed tomography demonstrated a mediastinal mass, pericardial invasion, and metastases to the lung. Examination of a biopsy specimen revealed thymic squamous cell carcinoma. Thus, a paraneoplastic syndrome, in this case hypercalcemia, does not exclude primary carcinoma of the thymus.