Bronchial anatomy is adequately demonstrated with the appropriate spiral computed tomographic technique on cross-sectional images, multiplanar reconstruction images, and three-dimensional reconstruction images. Contrary to the numerous variations of lobar or segmental bronchial subdivisions, abnormal bronchi originating from the trachea or main bronchi are rare. Major bronchial abnormalities include accessory cardiac bronchus (ACB) and "tracheal" bronchus. An ACB is a supernumerary bronchus from the inner wall of the right main bronchus or intermediate bronchus that progresses toward the pericardium. Fourteen ACBs were found in 17,500 consecutive patients (frequency, 0.08%). The term tracheal bronchus encompasses a variety of bronchial anomalies originating from the trachea or main bronchus and directed to the upper lobe. In a series of 35 tracheal bronchi, only eight originated from the trachea, three originated from the carina, and 24 originated from the bronchi. Displaced tracheal bronchi (27 of 35) are more frequent than supernumerary tracheal bronchi (eight of 35). Minor bronchial abnormalities include variants of tracheal bronchus, displaced segmental bronchi, and bronchial agenesis. The main embryogenic hypotheses for congenital bronchial abnormalities are the reduction, migration, and selection theories. Knowledge and understanding of congenital bronchial abnormalities may have important implications for diagnosis, bronchoscopy, surgery, brachytherapy, and intubation.

Purpose:To retrospectively evaluate pulmonary artery (PA) clot load scores and computed tomographic (CT) cardiovascular parameters as predictors of mortality in patients with severe pulmonary embolism (PE). Materials and Methods:Institutional review board approval was obtained with waiver of informed consent. A total of 82 consecutive patients (42 women, 40 men; mean age Ϯ standard deviation, 61 years Ϯ 15) were admitted to the intensive care unit for PE-related conditions and were evaluated by using CT pulmonary angiography. Two independent readers who were blinded to clinical outcome quantified PA clot load by using four scoring systems. Cardiovascular measurements included right ventricular (RV) and left ventricular (LV) short-axis measurements; RV short axis to LV short axis (RV/LV) ratios; main PA, ascending aorta, azygos vein, and superior vena cava diameters; and main PA diameter to aorta diameter ratios. Reflux of contrast medium into the inferior vena cava, leftward bowing of the interventricular septum, pleural or pericardial effusion, pulmonary consolidation, infarct, platelike atelectasis, and mosaic ground-glass opacity were also recorded. Results were correlated with patient outcome during hospital stay by using the Wilcoxon rank sum and 2 tests. Results:Twelve patients died within 1-14 days. RV and LV short axis; RV/LV ratio; azygos vein, superior vena cava, and aorta diameters; and contrast medium reflux into the inferior vena cava were significantly different between survivors and nonsurvivors (P Ͻ .05). No significant relationship was found between PA clot load and mortality rate. RV/LV ratio and azygos vein diameter allowed correct prediction of survival in 89% of patients (P Ͻ .001). Conclusion:RV/LV ratio and azygos vein diameter are predictors of mortality in patients with severe PE.

Background: Patients with acute pulmonary embolism (APE) present with a broad spectrum of prognoses. Computed tomographic pulmonary angiography (CTPA) has progressively been established as a first line test in the APE diagnostic algorithm, but estimation of short term prognosis by this method remains to be explored. Methods: Eighty two patients admitted with APE were divided into three groups according to their clinical presentation: pulmonary infarction (n = 21), prominent dyspnoea (n = 29), and circulatory failure (n = 32). CTPA studies included assessment of both pulmonary obstruction index and right heart overload. Haemodynamic evaluation was based on systolic aortic blood pressure, heart rate, and systolic pulmonary arterial pressure obtained non-invasively by echocardiography at the time of diagnosis of pulmonary embolism. Results: The mortality rate was 0%, 13.8% and 25% in the three groups, respectively. Neither the pulmonary obstruction index nor the pulmonary artery pressure could predict patient outcome. In contrast, a significant correlation with mortality was found using the systolic blood pressure (p,0.001) and heart rate (p,0.05), as well as from imaging parameters including right to left ventricle minor axis ratio (p,0.005), proximal superior vena cava diameter (p,0.001), azygos vein diameter (p,0.001), and presence of contrast regurgitation into the inferior vena cava (p = 0.001). Analysis from logistic regression aimed at testing for mortality prediction revealed true reclassification of 89% using radiological variables. Conclusion: These results suggest that CTPA quantification of right ventricular strain is an accurate predictor of in-hospital death related to pulmonary embolism.

We describe the abnormal magnetic resonance (MR) imaging findings in the deep digital flexor tendon (DDFT) and distal sesamoid bone in horses with radiographic changes compatible with navicular syndrome. Thirteen postmortem specimens were examined using a 1.5-T magnetic field, with spin echo (SE) T1-weighted, turbo SE (TSE) proton density-weighted (with and without fat saturation), and fat saturation TSE T2-weighted sequences. The limbs were then dissected to compare the MR findings with the gross assessment and histologic examination of the DDFT and distal sesamoid bones. Tendonous abnormalities were detected by MR imaging in 12 DDFTs and confirmed at necropsy. Most tendon lesions were located at the level of the distal sesamoid bone and the proximal recess of the podotrochlear bursa. Tendon lesions were classified based on their MR imaging features as core lesions, dorsal lesions, dorsal abrasions, and parasagittal splits. Areas of increased MR signal in the DDFTs were characterized by tendon fiber disturbance and lack of continuity of the collagen fibers, foci of edema, hemorrhages, and formation of lakes containing eosinophilic plasma-like material or amphophilic material of low density. Bone marrow signal alterations in the distal sesamoid bone were seen in all digits. Two main phenomena were responsible for the abnormal signal, respectively, in T1-weighted (decreased signal) and in T2-weighted fat-suppressed images (increased signal): a decrease in the fat marrow content in the trabecular spaces and an increase in the fluid content. Histologic examination revealed foci of bone marrow edema, hemorrhage, necrosis, and fibrosis. Cyst formation and trabecular abnormalities (disorganization, thinning, remodelling) were also observed in areas of abnormal signal intensity. Increased bone density because of trabecular thickening induced a decrease in signal in all sequences.

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