Lung nodule enhancement at CT: multicenter study.

PURPOSE: To test the hypothesis that absence of statistically significant lung nodule enhancement (< or =15 HU) at computed tomography (CT) is strongly predictive of benignity. MATERIALS AND METHODS: Five hundred fifty lung nodules were studied. Of these, 356 met all entrance criteria and had a diagnosis. On nonenhanced, thin-section CT scans, the nodules were solid, 5-40 mm in diameter, relatively spherical, homogeneous, and without calcification or fat. All patients were examined with 3-mm-collimation CT before and after intravenous injection of contrast material. CT scans through the nodule were obtained at 1, 2, 3, and 4 minutes after the onset of injection. Peak net nodule enhancement and time-attenuation curves were analyzed. Seven centers participated. RESULTS: The prevalence of malignancy was 48% (171 of 356 nodules). Malignant neoplasms enhanced (median, 38.1 HU; range, 14.0-165.3 HU) significantly more than granulomas and benign neoplasms (median, 10.0 HU; range, -20.0 to 96.0 HU; P < .001). With 15 HU as the threshold, the sensitivity was 98% (167 of 171 malignant nodules), the specificity was 58% (107 of 185 benign nodules), and the accuracy was 77% (274 of 356 nodules). CONCLUSION: Absence of significant lung nodule enhancement (< or = 15 HU) at CT is strongly predictive of benignity.

Intermittent antegrade tepid versus cold blood cardioplegia in elective myocardial revascularization.

BACKGROUND: The ideal temperature for blood cardioplegia administration remains controversial. METHODS: Fifty-two patients who required elective myocardial revascularization were prospectively randomized to receive intermittent antegrade tepid (29 degrees C; group T, 25 patients) or cold (4 degrees C; group C, 27 patients) blood cardioplegia. RESULTS: The two cohorts were similar with respect to all preoperative and intraoperative variables. The mean septal temperature was higher in group T (T, 29.6 degrees +/- 1.1 degrees C versus 17.5 degrees +/- 3.0 degrees C; p < 0.0001). After reperfusion, group T exhibited significantly greater lactate and acid release despite similar levels of oxygen extraction (p < 0.05). The creatine kinase-MB isoenzyme release was significantly lower in group T (764 +/- 89 versus 1,120 +/- 141 U x h/L; p < 0.04). Hearts protected with tepid cardioplegia demonstrated significantly increased ejection fraction with volume loading, improvement in left ventricular function at 12 hours, and decreased need for postoperative inotropic support (p < 0.05). The frequency of ventricular defibrillation after cross-clamp removal was lower in this cohort (p < 0.05). There were no hospital deaths, and both groups had similar postoperative courses. CONCLUSIONS: Intermittent antegrade tepid blood cardioplegia is a safe and efficacious method of myocardial protection and demonstrates advantages when compared with cold blood cardioplegia in elective myocardial revascularization.

Accuracy of high-resolution CT in diagnosing lung diseases.

OBJECTIVE: The purpose of our study was to determine if high-resolution CT facilitates the diagnoses of three diseases that cause cystic air spaces in the lungs: pulmonary eosinophilic granuloma, pulmonary lymphangiomyomatosis, and emphysema. MATERIALS AND METHODS: Retrospective review of high-resolution CT findings in patients with pathologically proven pulmonary eosinophilic granuloma (n = 10), pulmonary lymphangiomyomatosis (n = 9), and emphysema (n = 10) and five control patients without cystic air spaces was conducted by two thoracic radiologists unaware of the pathologic diagnosis. After reviewing the scans, the radiologists made a diagnosis and indicated their level of confidence in the diagnosis on a three-point scale. RESULTS: High-resolution CT allowed the two radiologists to be confident of the diagnosis of pulmonary eosinophilic granuloma in 84% of CT scans, lymphangiomyomatosis in 79%, and emphysema in 95%. When confident, the observers were correct in 100% of the cases. Agreement between observers was good for confident diagnoses based on high-resolution CT scans of pulmonary eosinophilic granuloma (kappa = .77), lymphangiomyomatosis (kappa = .88), and emphysema (kappa = 1). Distribution of cystic changes differed on high-resolution CT scans for lymphangiomyomatosis and pulmonary eosinophilic granuloma. No consistent distribution pattern was observed for emphysema. Lack of a perceptible cyst wall was unique to cases of emphysema. All patients with lymphangiomyomatosis lacked nodules in the intervening lung parenchyma, whereas most patients with pulmonary eosinophilic granuloma had parenchymal nodules. CONCLUSION: High-resolution CT can help radiologists reliably diagnose pulmonary eosinophilic granuloma, lymphangiomyomatosis, and emphysema.

Mosaic pattern of lung attenuation on CT scans: frequency among patients with pulmonary artery hypertension of different causes.

OBJECTIVE: The purpose of this study was to determine the frequency with which a mosaic pattern of lung attenuation is seen on chest CT scans in patients with various causes of pulmonary artery hypertension (PAH). MATERIALS AND METHODS: Chest CT scans of 64 patients with known PAH were reviewed to assess the patterns of lung attenuation. Patterns of lung attenuation were divided into three categories: class I, homogeneous lung parenchymal attenuation; class II, slightly heterogeneous lung attenuation that does not conform to the anatomic boundaries of the secondary pulmonary lobule; and class III (mosaic pattern), heterogeneous lung attenuation in geographic regions with well-defined borders corresponding to the anatomic units of single or multiple secondary pulmonary lobules. The patients medical histories were reviewed to determine the primary cause of PAH for each patient. RESULTS: Peak pulmonary artery pressure of the patients in our study averaged 74 mm Hg (range, 36-194 mm Hg). Twenty-one patients had PAH due to lung disease: 17 patients, due to cardiac disease; and 23 patients, due to vascular disease. Three other patients had PAH due to miscellaneous causes. Of the 23 patients with PAH due to vascular disease, 17 patients (74%) had a mosaic pattern of lung attenuation. Of the 21 patients with PAH due to lung disease, one patient (5%) had a mosaic pattern of lung attenuation. Among the 17 patients with PAH due to cardiac disease, two patients (12%) had a mosaic pattern of lung attenuation. A mosaic pattern of lung attenuation was seen significantly more often in patients with PAH due to vascular disease than in patients with PAH due to cardiac or lung disease. CONCLUSION: A mosaic pattern of lung attenuation can be seen on CT scans in patients with PAH due to vascular disease, cardiac disease, or lung disease. However, the mosaic pattern is seen significantly more often in patients with PAH due to vascular disease than in patients with PAH due to cardiac or lung disease.

Elastofibroma dorsi: radiologic findings in 12 patients.

OBJECTIVE: We report radiologic findings in 12 patients with elastofibroma dorsi to heighten radiologist awareness of the imaging characteristics of these benign, often asymptomatic lesions. Because these lesions can usually be diagnosed on the basis of their imaging characteristics, increased awareness of these characteristics will decrease misdiagnosis of these lesions as malignancies and avoid unnecessary biopsies and surgeries. MATERIALS AND METHODS: We retrospectively reviewed the radiology and pathology of nine patients with surgically excised elastofibromas and the radiology of three patients with radiologically diagnosed elastofibromas. RESULTS: Twenty-one elastofibromas were imaged in 12 patients. Female-to-male ratio was 5:1; mean age was 65 years old. Of the nine patients in whom both sides of the chest wall were imaged, all (100%) had bilateral elastofibromas. Nineteen elastofibromas (90%) had the typical CT and MR appearances described in the literature: a poorly circumscribed, heterogeneous soft-tissue mass, with tissue of attenuation or signal intensity similar to that of skeletal muscle interlaced with strands of fat. One elastofibroma imaged twice over a 4-year period showed interval growth. All elastofibromas were sub- or infrascapular or in both locations. Of the 21 elastofibromas imaged, only four were perceived by the initial interpreting radiologist, and of these, only one was correctly diagnosed. CONCLUSION: Our study shows that many radiologists may not be aware of the diagnosis of elastofibroma, as few of the cases in our series were perceived or correctly diagnosed by the interpreting radiologist. Our cases show many of the classic findings of elastofibromas described in the literature. In addition, our series shows that elastofibromas are commonly bilateral, a feature that has not been strongly emphasized in the literature but one that is helpful in making the radiologic diagnosis. The finding of a similar contralateral lesion, when present, virtually eliminates malignancy from the differential diagnosis and further supports the presumptive diagnosis of elastofibromas. Increased awareness of the characteristic appearance and location of these benign, often asymptomatic lesions will increase radiologic diagnosis, decrease the need for biopsy, and decrease surgical removal of elastofibromas as presumed malignancies.

The radiographic findings of fibrosing mediastinitis.

We retrospectively reviewed the radiographic findings of fibrosing mediastinitis (FM) in 33 patients. Imaging studies included chest radiographs, computed tomographic scans, magnetic resonance imaging examinations, esophograms, ventilation perfusion scans, angiograms, and venograms. Findings include bronchial narrowing in 11 patients (33 percent), pulmonary artery obstruction/narrowing in 6 patients (18 percent), esophageal narrowing in 3 patients (9 percent), and superior vena cava obstruction/narrowing in 13 patients (39 percent). Two distinctly different radiographic patterns were identified: a localized pattern seen in 27 patients (82 percent) that frequently contained calcification and a diffuse pattern seen in 6 patients (18 percent) that did not contain calcification. The localized pattern is most likely due to histoplasmosis and does not show radiographic evidence of improvement with steroid therapy. The diffuse pattern may more likely be truly idiopathic or of a noninfectious etiology. Several patients with the diffuse pattern showed radiographic evidence of improvement with steroid therapy.