Distinguishing viable from infarcted myocardium after experimental ischemia and reperfusion by using nuclear magnetic resonance imaging.

Early reperfusion has the potential for salvaging ischemic myocardium at risk for infarction. To test the ability of nuclear magnetic resonance (NMR) imaging to differentiate between stunned and infarcted myocardium early after reperfusion, 16 mongrel dogs underwent transient occlusion of the left anterior descending artery or a diagonal branch for 30, 60 or 180 min followed by reperfusion. To identify the area at risk for infarction and to assess the extent of hypoperfusion and reperfusion, two-dimensional and contrast echocardiography were performed at baseline study, during coronary occlusion and at three separate times during reperfusion (before NMR imaging, immediately after NMR imaging and 12 to 14 h later). Wall thickening in the control and ischemic zones and the circumferential extent of abnormal wall motion were analyzed at each time point using short-axis echocardiograms. Nuclear magnetic resonance imaging at 1.5 tesla was performed 2 to 3.5 h (mean 2.7 +/- 0.5) after reperfusion. Short-axis, multislice spin-echo images (TE 26 and TE 60) were obtained. Signal intensity was measured in the control and ischemic areas and expressed as a percent difference compared with normal myocardium. All dogs demonstrated a significant decrease in wall thickening and abnormal wall motion before and after NMR imaging. Seven of the eight dogs with infarction had an area of increased signal intensity on TE 60 images. The mean percent difference in signal intensity compared with adjacent normal myocardium was 127 +/- 68% (p = 0.002). None of the eight dogs without infarction had a visually apparent change in signal intensity on TE 60 images (mean percent difference versus control area 13 +/- 11%), despite regional systolic dysfunction documented by echocardiography at the time of imaging. The area of increased signal intensity correlated with infarct size (r = 0.69), although overestimation by NMR imaging occurred. The area of increased signal intensity did not correlate with the extent of echocardiographic contrast defect during coronary occlusion (risk area). This study demonstrates that NMR imaging can be applied early after coronary reperfusion to assess the potential for recovery of dysfunctional myocardium. In addition, by using a TE 60 multislice spin-echo imaging sequence at 1.5 tesla, quantification of the extent of infarction also may be possible.

Imaging of lung cancer: old and new.

Lung cancer is the leading cause of cancer death in the United States. Lung cancer is frequently encountered by the radiologist, whether the lung cancer is detected on a chest radiograph obtained in a symptomatic patient, or is an incidental finding. The radiologic workup of pulmonary lesions suspected of being lung carcinoma has evolved as new technology has become available. Current imaging modalities which are useful in the workup of suspected lung cancers include plain radiography, computed tomography, magnetic resonance imaging, with the recent addition of positron emission tomography and endoscopic ultrasound. The following article discusses the merits of these imaging modalities and their role in the workup of patients with lung cancer.

Spurious thyroid cancer metastasis: saliva contamination artifact in high dose iodine-131 metastases survey.

The use of high dose 131I for workup of thyroid cancer patients increases the chance of contamination artifact which may mimic metastases. Two elderly male patients with follicular carcinoma of the thyroid had salivary contamination artifacts on metastatic survey scans. These patients received a 1 and 10 mCi dose of 131I, respectively. The artifacts were recognized only retrospectively when follow-up scans were obtained and compared. The characteristics of contamination artifacts and several methods to confirm these are discussed.

Treatment of pneumothoraces utilizing small caliber chest tubes.

Pneumothorax is a common problem in both hospitalized and emergency room patients. Eight-four pneumothoraces in 79 patients were treated using a No. 9 French catheter. In 76 cases, the catheter was attached to a flutter valve, and in eight cases, suction was applied. The No. 9 French catheter provided definitive treatment in 73 (87 percent) of the pneumothoraces. Causes of catheter failure included kinking, malposition, inadvertent removal by patient, occlusion of the tube or valve by pleural fluid, and large air leak. No complication attributable to tube placement occurred. When the flutter valve was employed, the patient was able to ambulate allowing for potential outpatient therapy. The tube was found to be easy to use, safe, and efficacious in the treatment of pneumothoraces.

Regional pulmonary distribution of iodine-125-labeled oleic acid. Its relationship to the pattern of oleic acid edema and pulmonary blood flow.

Oleic acid infusion in dogs produces a patchy, predominantly peripheral lesion on CT scans. This study correlates the pattern of oleic acid injury with the distribution of infused oleic acid and pulmonary blood flow. Radiolabeled oleic acid (I-125, 0.05 ml/kg) and radiolabeled 15-micron microspheres (Co-57) were infused into the right atria of 11 dogs. Oleic acid was given after the microspheres in six dogs and before microspheres in five dogs. Ten minutes after infusion, the lungs were removed. Four transverse slices (0.5 cm thick) of the lower lobes were taken from each dog and cubed. Samples were grouped into three regions of the transverse slice: outer, middle, and inner concentric rings. In both groups, I-125 (oleic acid) activity was greater in the outer than the middle and inner concentric layers (P less than 0.001). When Cobalt-57 microspheres were given before oleic acid, Cobalt-57 activity was marginally lower in the outer layer compared with the middle and inner layers. However, when oleic acid was given first, microsphere activity in the outer layer was significantly lower (P less than 0.001) than the middle layer. Thus, oleic acid was preferentially distributed to the peripheral regions of the lung, similar to the regions of injury on CT. This distribution did not correspond to the pattern of pulmonary blood flow as indicated by the microspheres. Immediately after oleic acid infusion, pulmonary blood flow to the periphery was reduced, reflecting a response to the predominantly peripheral injury by oleic acid.

Interventional chest radiology.

Interventional radiology has important applications for the diagnosis and treatment of chest diseases. Fine-needle aspiration biopsy of a lung nodule is the most commonly performed procedure, but lesions in the mediastinum, hilum, and chest wall also can be biopsied. Needle aspiration and catheter drainage help in treating pleural effusion, empyema, and lung and mediastinal abscesses. Emphasis on teamwork and patient care is essential. In this article, the authors offer practical advice on how and when to undertake these procedures and how to manage any associated complications.

Symposium on Nonpulmonary Aspects in Chest Radiology. The diaphragm.

The diaphragm is the main muscle of ventilation and the chief barrier separating the thorax from the abdomen. This article discusses diaphragmatic anatomy, physiology, pathology, and radiology, including hernia, eventration, rupture, tumors, paralysis, weakness, and fatigue. Imaging of the diaphragm involves plain radiography, fluoroscopy, computed tomography, and ultrasonography.

The value of good medical student teaching: increasing the number of radiology residency applicants.

RATIONALE AND OBJECTIVES: The authors attempted to define the value of good medical student teaching to the profession of radiology by examining the effect of radiology course improvements on the number of 4th-year students applying to radiology residencies. MATERIALS AND METHODS: Course evaluation and residency application data were obtained from six consecutive classes of 4th-year medical students at the study institution, and these data were compared with national data. RESULTS: Between 1995 and 2000, the number of 4th-year U.S. medical students applying to radiology increased 1.6 times. At the study institution, that number increased 4.5 times, a statistically significant difference (P = .020, chi2 test). Student survey data indicate that this increase reflects a general increase in the quality of radiology teaching in the study institution and specific changes in a required 2nd-year medical school course. CONCLUSION: These results strongly suggest that good medical student teaching pays important dividends, not only to the departments that provide it but also to the profession of radiology as a whole. Exposing students to good radiology teaching early in their medical school careers is especially important. Radiology departments that provide outstanding medical student education should be studied to help develop a model of educational best practices.

Subepithelial pyeloureteric lesions in patients with nephrostomy tubes.

Mural filling defects were identified in the renal pelves or ureters in five patients with nephrostomy tubes. In two patients, infection was documented. In the remaining patients, the urine was sterile. While typical ureteritis cystica associated with infection may be seen in patients with nephrostomy tubes, in some patients, other mechanisms are responsible for this appearance.

Meandering bullet in the pericardial sac: to remove or not to remove.

Patients with bullets in the pericardial sac without obvious myocardial injuries are rare, making it difficult to analyze the natural history and propose management approaches. We present the case of a meandering bullet in the pericardial sac and a review of the literature.

Traumatic rupture of the aorta. Indications for aortography.

The indications for thoracic aortography in the blunt chest trauma patient remain controversial. Clinical and radiographic findings in 102 patients seen at a Level I Trauma Center over a five-year period were reviewed to evaluate criteria predictive of major thoracic vascular injury. Five patients had positive aortograms. There was no significant correlation with Revised Trauma Score, symptoms, or associated thoracic injuries, although patients with aortic rupture did have a higher incidence of extrathoracic injuries (P less than 0.001). A blinded review of admitting chest radiographs for five major findings (widened mediastinum, aortic arch abnormalities, aortopulmonary window opacification, left apical capping, and right apical capping) revealed a significant difference between patients with and without aortic injury (0.98 +/- 1.24 findings in the negative aortogram group and 3.00 +/- 0.71 findings in the positive aortogram group) (P less than 0.001). All patients with aortic rupture had at least two major positive findings on admitting chest radiographs. Admission chest x-ray evidence of at least one major abnormality is a safe method of screening blunt chest trauma patients for thoracic aortography.

Current concepts of left ventricular pseudoaneurysm: pathophysiology, therapy, and diagnostic imaging methods.

Left ventricular pseudoaneurysm represents a cardiac rupture which is temporarily confined by pericardium and is amenable to curative surgical treatment. The case described illustrates several atypical features of its presentation and diagnosis, highlighting the importance of maintaining a sufficient clinical index of suspicion for this relatively uncommon, but potentially lethal entity. The use of various diagnostic imaging methods is described, including the first description of magnetic resonance imaging of ventricular pseudoaneurysm. The prospect of medical therapies directed toward the prevention of cardiac rupture, and thus pseudoaneurysm, is discussed in the context of its pathophysiology which involves alterations in the cardiac fibroskeletal support.

Noninfectious and nonmalignant pulmonary disease in AIDS.

Infectious and malignant disease processes are responsible for most pulmonary abnormalities seen in patients with acquired immunodeficiency syndrome (AIDS). There are, however, a number of noninfectious and nonmalignant disorders that can involve the lungs of these individuals. Nonspecific interstitial pneumonitis and lymphocytic interstitial pneumonitis may mimic opportunistic infections both clinically and radiographically. Congestive cardiomyopathy may develop and result in pulmonary edema. Other disorders such as alveolar proteinosis and desquamative interstitial pneumonitis are also reported. Bronchoalveolar lavage, a diagnostic technique frequently employed in AIDS patients, may itself produce pulmonary opacities. Knowledge of these disorders may aid in the evaluation of AIDS patients for whom an infectious etiology for pulmonary abnormalities cannot be found.

Painful transthoracic needle biopsy: a sign of neurogenic tumor.

Neurogenic tumors most commonly appear initially as posterior mediastinal masses. These tumors, however, may occur in other intrathoracic locations and present a diagnostic challenge. In such cases transthoracic fine-needle aspiration (FNA) often is used to make a definitive diagnosis. This procedure usually does not result in severe pain. We report two patients who experienced severe pain during transthoracic FNA of neurogenic tumors. We believe that severe pain associated with transthoracic needle biopsy of an intrathoracic mass is suggestive of a neurogenic tumor. When pain accompanies this procedure, a cytopathologist should be notified so that specific immunostaining techniques can be performed to confirm the diagnosis.

Pleural cryptococcosis.

Pleural infection by Cryptococcus neoformans is uncommon and when present typically occurs in the immunocompromised host. We report two renal transplant patients who developed pleural cryptococcosis.

Pediatric digital chest imaging.

The Philips Computed Radiography system performs well with pediatric portable chest radiographs, handling the throughout of a busy intensive care service 24 hours a day. Images are excellent and routinely provide a conventional (unenhanced) image and an edge-enhanced image. Radiation dose is decreased by the lowered frequency of repeat examinations and the ability of the plates to respond to a much lower dose and still provide an adequate image. The high quality and uniform density of serial PCR portable radiographs greatly enhances diagnostic content of the films. Decreased resolution has not been a problem clinically. Image manipulation and electronic transfer to remote viewing stations appear to be helpful and are currently being evaluated further. The PCR system provides a marked improvement in pediatric portable chest radiology.

Reexpansion pulmonary edema.

Reexpansion pulmonary edema is a rare complication attending the rapid reexpansion of a chronically collapsed lung, such as occurs after evacuation of a large amount of air or fluid from the pleural space. The condition usually appears unexpectedly and dramatically-immediately or within 1 h in 64% of patients and within 24 h in the remainder. The clinical manifestations are varied; they range from roentgenographic findings alone in asymptomatic patients to severe cardiorespiratory insufficiency. The radiographic evidence of reexpansion pulmonary edema is a unilateral alveolar filling pattern, seen within a few hours of reexpansion of the lung. The edema may progress for 24-48 h and persist for 4-5 days. Human data on the pathophysiology of reexpansion pulmonary edema derive from small series of patients, case reports, and reviews of the literature. On the other hand, a larger body of data exists on experimental reexpansion pulmonary edema in cats, monkeys, rabbits, sheep, and goats. This review examines the clinical and experimental evidence for reexpansion pulmonary edema. In addition, we detail the historical background, clinical setting, treatment, and outcome of reexpansion pulmonary edema.

Tracheoesophageal fistula due to Wegener granulomatosis.

Most acquired tracheoesophageal fistulas (TEFs) are due to malignant disease processes, with nonmalignant causes infrequently encountered. We report a patient with a TEF caused by Wegener granulomatosis. The radiographic findings of this rare cause of TEF are described.

Imaging the diaphragm and its disorders.

Although a radiologic evaluation of the diaphragm is important in many clinical situations, visualization of the diaphragm is difficult because of its thinness, its domed contour, and its contiguity with abdominal soft tissues. Each clinical situation involving the diaphragm presents its own imaging difficulties, and each radiographic technique has advantages and disadvantages. No one modality is best for all situations. Often, several imaging modalities must be used to resolve the clinical question. The particular difficulties in diaphragmatic imaging are (1) distinguishing eventration from paralysis or hernia, (2) distinguishing lipoma from herniated omental fat, and (3) distinguishing unilateral paralysis from weakness and bilateral paralysis from respiratory fatigue. By selecting and applying the appropriate radiographic techniques, the radiologist can serve an essential role in assessing the disorders of the diaphragm.

Unilateral bronchiectasis and esophageal dysmotility in congenital adult tracheoesophageal fistula.

Tracheoesophageal fistulas (TEF) in adults are most commonly neoplastic, and very rarely congenital in nature. We report a 45-year-old Hispanic male with TEF and initial presentation of minimal hemoptysis. The patient had radiographic evidence of unilateral upper lobe (RUL) bronchiectasis, massive esophageal dilatation, and dysmotility. However, there was no evidence of esophageal malignancy, achalasia, or Chagas' disease. Bronchoscopy revealed a large TEF in the posterior wall of trachea, which was not visualized on esophagram or esophagoscopy. Bronchoalveolar lavage (BAL) cultures grew Mycobacterium avium complex (MAC). Our report illustrates that idiopathic, or congenital, TEF can be associated with esophageal dysmotility, adulthood bronchiectasis, and atypical mycobacterial superinfection.