Imaging features of intrapancreatic accessory spleen.

Although accessory spleens are commonly identified on CT, intrapancreatic accessory spleen (IPAS) is often not recognised or is mistaken for other pancreatic lesions. Currently, with improved cross-sectional techniques and spatial resolution, IPAS is more detectable. We report the imaging features and work-up for the differentiation between IPAS and other pancreatic lesions. An index case of a suspected pancreatic tail islet cell tumour, subsequently confirmed as IPAS, led to inquiries into the incidence of IPAS and the means of preventing unnecessary surgery. For 2 years, we searched for IPAS during our daily interpretations and compared these cases with those taken from our institution's database to determine the distinguishing characteristics. Three proven cases of IPAS, which mimicked pancreatic tail lesions on CT, are presented. Nine patients with suspected IPAS, based on imaging characteristics and stability, are also described. All cases of IPAS are well defined, 1-3 cm in size, follow the density and intensity of the spleen on CT and MRI, and accumulate technetium-99m ((99)Tc(m)) sulphur colloid and (99)Tc(m) heat damaged red blood cell scintigraphy (in contrast to other lesions). In conclusion, radiologists should be aware that a subtle pancreatic tail lesion could be an IPAS. A high index of suspicion will lead to correlative imaging. A combination of CT, MRI and nuclear medicine examinations can confirm the diagnosis and prevent unnecessary surgery.

Chest radiographic image quality: comparison of asymmetric screen-film, digital storage phosphor, and digital selenium drum systems--preliminary study.

Conventional screen-film radiography does not display all regions of the thorax satisfactorily. Three chest radiographic techniques display both the lung and the mediastinum with good contrast. These techniques are asymmetric screen-film (ASF), digital storage phosphor (DSP), and digital selenium drum (DSD) imaging. ASF systems use two asymmetric screen-film combinations to produce a wide-latitude image of the thorax with good contrast in the lungs. In DSP systems, image data are acquired digitally with a wide dynamic range by using the optical output of a photostimulable phosphor plate; in DSD systems, the wide-range digital image data are acquired by using the electronic charge generated on a drum coated with a thin layer of amorphous selenium. The appearance of a DSP or DSD radiograph is then determined by user-selected image processing operations: tone scaling, spatial frequency processing, and dynamic range compensation. Digital chest radiographs processed with strong regional equalization provide both excellent contrast in the lungs and effective display of the mediastinum and chest wall. At visual comparison, the high lung contrast and good mediastinal, retrocardiac, and subdiaphragmatic detail provided by the DSD method distinguish it from the other two methods.

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.

Lung torsion: preoperative diagnosis with angiography and computed tomography.

In a patient with lung torsion, computed tomography demonstrated an occluded right upper lobe bronchus with opacified posterior lung. A pulmonary angiogram demonstrated the right upper lobe artery to be posteriorly and inferiorly displaced into the consolidated lung. In selected cases, computed tomography and angiography can help to confirm a torsed lung.

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.

Saphenous vein graft aneurysm after coronary artery bypass surgery.

OBJECTIVE: The purpose of this report is to show the imaging characteristics of saphenous vein graft aneurysms and pseudoaneurysms. Conventional radiographic, CT, and coronary angiography images were reviewed for three patients ranging from 64 to 69 years old who had documented saphenous vein graft aneurysms or pseudoaneurysms. CONCLUSION: Saphenous vein graft aneurysms and pseudoaneurysms appear as paracardiac, hilar, or mediastinal masses on chest radiographs. On CT, the lesions are enhancing tubular mixed-attenuation masses along the heart border. Coronary angiography confirms the graft dilatations. Knowing the imaging characteristics of these entities should lead to their diagnosis and prevent unnecessary complications.

Splenic trauma: value of follow-up CT.

PURPOSE: To determine the value of follow-up computed tomography (CT) after expectant treatment in patients with clinically stable blunt splenic trauma. MATERIALS AND METHODS: Medical records and CT studies for 42 patients were reviewed, and injuries were graded on a scale of 1-6. Patients were divided into three groups: stable patients with no follow-up CT (group 1, n = 14), stable patients with follow-up CT (group 2, n = 22), and symptomatic patients with follow-up (group 3, n = 6). Serial hemoglobin values and clinical findings at follow-up CT were reviewed. RESULTS: All patients in groups 1 and 2 remained clinically stable with good outcomes. In group 3, follow-up CT scans demonstrated worsening condition in four patients (67%), and three of the four had poor outcomes. CONCLUSION: Follow-up CT may be unnecessary in patients with clinically stable splenic trauma.

Computed tomography of the chest in the intensive care unit.

Two recent reports evaluated thoracic CT in critically ill patients. One looked at 87 patients with concurrent mobile chest radiographs and CT scans. CT provided unsuspected significant diagnostic information in 61 of the 87 patients. Examples included malpositioned or occluded chest tube, unsuspected large pleural effusion, empyema, pneumothorax, lung abscess, and pericardial effusion/thickening. In addition, two patients with prolonged adult respiratory distress syndrome and fever were shown by CT to have bronchiectasis as the likely explanation for the fever. Similar results were reported in the other series. Our experience concurs, and suggests that although chest CT is not needed in the majority of ICU patients, it is tremendously helpful in patients whose clinical course is not explained by the available information or whose chest radiographs are difficult to interpret.

Enlarging pleural effusion after liver transplantation.

Ten of 42 patients who underwent liver transplantation were retrospectively found to have enlarging pleural effusions later than 3 days after transplantation. Seven of the 10 patients had subdiaphragmatic pathology, including 4 with hematomas, 1 with a biloma, and 2 with abscesses. One patient with a subphrenic abscess also had an empyema. Patients with a enlarging pleural effusion later than 3 days after transplantation should be evaluated for subdiaphragmatic pathology.

Radiology of the pleural fissures.

The pleural fissures, formed by a double layer of visceral pleura, represent extensions of the pleural space between lobes of the lungs. The fissures are frequently an anatomic barrier to the spread of inflammatory or neoplastic disease. Identification of the fissures is important for the accurate localization of lung parenchymal or pleural pathology. The plain radiographic and computed tomographic (CT) imaging of normal and variant fissural anatomy, as well as of some abnormalities that may affect the fissures will be reviewed and illustrated.

Sagittal orientation of the anterior minor fissure: radiography and CT.

Chest radiographs of 12 patients revealed an oblique, predominantly cephalocaudal linear opacity in the anterior inferomedial aspect of the right lung. Correlation with high-resolution computed tomography in two patients indicated that this opacity represented a sagittal orientation of the anterior minor fissure, with resultant inferomedial curving of the right upper lobe of the lung along the right border of the heart. The sagittal anterior minor fissure may extend inferiorly to the right hemidiaphragm and merge superiorly with the horizontal minor fissure. Autopsy findings in one case showed that this anatomic variant may explain potentially confusing radiographic manifestations of disease in the anterior segment of the right upper lobe of the lung and in the medial segment of the right middle lobe of the lung.

Bronchogenic carcinoma metastatic to normal-sized lymph nodes: frequency and significance.

CT staging of mediastinal lymph node metastases from bronchogenic carcinoma is a subject of considerable controversy. The frequency of metastases to normal-sized lymph nodes is a critical issue related to the sensitivity of CT. The authors prospectively examined 42 patients with bronchogenic carcinoma with CT; in 39, careful surgical-pathologic correlation of mediastinal lymph node status was possible. Only 7% had metastases limited to mediastinal lymph nodes that were normal-sized at CT. This reflected a low overall frequency of metastases to normal-sized nodes and several diagnostic factors that converted potentially false-negative studies into true-positive CT studies. In this small series, metastases to enlarged nodes were more likely to have extracapsular spread of tumor, a poor prognostic factor. Overall, the authors do not consider metastases to normal-sized mediastinal lymph nodes to be a major problem in CT staging of non-small cell lung cancer.

Transthoracic needle aspiration biopsy: evaluation of the blood patch technique.

A study was undertaken to evaluate the effectiveness of the blood patch technique in the prevention of pneumothorax after transthoracic needle aspiration biopsy. A total of 140 needle biopsies were performed with a coaxial system. Two groups of patients were defined according to whether or not autologous blood was injected into the introducing needle as it was withdrawn after needle aspiration biopsy. Fifty-two biopsies were performed with the blood patch technique (group A), while 88 biopsies were performed without the blood patch technique (group B). The frequency of postbiopsy pneumothorax was 28.8% (15 of 52 patients) in group A and 34.1% (30 of 88 patients) in group B. Chest tube insertion was required in 7.7% (four of 52 patients) in group A and in 9.1% (eight of 88 patients) in group B. There was no statistically significant difference in pneumothorax rate and chest-tube insertion rate between the two groups (P greater than .05). In this series of 140 biopsies, the blood patch technique failed to affect the rate of pneumothorax after transthoracic needle aspiration biopsy.

CT evaluation of enhancing mediastinal masses.

The CT scans of 132 patients with mediastinal masses and CT scans from our teaching file were retrospectively reviewed to evaluate the role of contrast enhancement in limiting the differential diagnosis of a mediastinal mass. Ten patients with an enhancing mediastinal mass were found. Coupled with mass enhancement, location and hypertension were helpful in limiting the differential diagnosis. Four masses were of thyroid origin, and all were contiguous with neck thyroid. All patients with functioning paragangliomas were hypertensive and all intrapericardial enhancing masses were functioning paragangliomas. A normotensive patient had a nonfunctioning aortic body paraganglioma superiolateral to the aortic arch. An enhancing mass in a similar location in a hypertensive patient was a functioning paraganglioma. Castleman disease occurred posterior to the heart.

CT evaluation of mediastinal masses.

CT is an important modality for imaging mediastinal masses, and certain CT attenuation features (fat, calcium, or water attenuation, contrast enhancement) are well known to suggest specific diagnoses. In a series of 132 consecutive patients with tissue-proven mediastinal masses, these specific CT features were present in only 16. We evaluated the ability of CT to differentiate soft tissue mediastinal masses based on morphology and distribution of disease. Metastatic disease and lymphoma accounted for 69% of masses in this series, and CT could not generally differentiate them. However, CT was helpful in differential diagnosis in certain settings. CT demonstration of multiple mediastinal masses when conventional radiographs showed a single mass generally excluded diagnoses such as thymoma and teratoma. CT demonstration of a single middle mediastinal mass, frequently missed by conventional radiography, made metastatic disease a much more likely diagnosis than lymphoma. Finally, CT demonstration of certain ancillary findings strongly favored a diagnosis of lymphoma (axillary adenopathy) or metastatic disease (solitary pulmonary mass, focal liver lesions, bone lesions).

Metallic mercury pulmonary emboli.

We report the radiographic appearance of a patient with metallic mercury pulmonary emboli. The mercury emboli appear as metallic densities in both a branching pattern and as tiny spherules. The differential diagnosis includes aspirated mercury or barium and barium pulmonary emboli. The recognition of either intracardiac or intragastrointestinal mercury can limit this differential diagnosis.

Right-pneumonectomy syndrome: radiologic findings and CT correlation.

The clinical history and radiographic and bronchoscopic findings were reviewed retrospectively in five patients with right-pneumonectomy syndrome, a rare, delayed complication of pneumonectomy of the right lung. Four patients had undergone pneumonectomy in childhood or adolescence. Presenting symptoms of dyspnea and recurrent pulmonary infections in the left lung were associated with radiographic evidence of marked rightward and posterior deviation of the mediastinum, counterclockwise rotation of the heart and great vessels, and herniation of the left lung into the right, anterior side of the chest. Computed tomography, performed in four patients, best demonstrated resultant compression of the distal trachea and left main bronchus between the aorta and pulmonary artery. Malacia of the major airways (n = 4 cases) and mediastinal shift was visualized only with fluoroscopy and was confirmed by bronchoscopy. Because of the morbidity and mortality associated with dyspnea and recurrent pulmonary infections, proper radiologic evaluation is crucial, and surgical intervention is often necessary.