ABSTRACT
Segmental or lobar atelectasis is a common radiographic finding in patients with bronchial obstruction. Although in many cases the presence and cause of atelectasis can be ascertained from the plain chest radiograph, computed tomography (CT) often provides valuable additional information, particularly with regard to the precise location and extent of the obstructing process. CT also can be used to differentiate between benign and malignant causes of obstructive atelectasis. After administration of intravenous contrast material, CT may distinguish a proximal obstructing tumor from collapsed lung or adjacent mediastinal structures. In some patients, magnetic resonance imaging (MRI) can provide comparable and/or complementary information. In this article, we review the major applications of CT and MRI, as well as the capabilities and limitations of both techniques, in the evaluation of patients with obstructive atelectasis.
Subject(s)
Lung Diseases, Obstructive/diagnosis , Magnetic Resonance Imaging , Pulmonary Atelectasis/diagnosis , Tomography, X-Ray Computed , Diagnosis, Differential , Humans , Lung/pathology , Lung Diseases, Obstructive/etiology , Pulmonary Atelectasis/complicationsABSTRACT
PURPOSE: To investigate the effect of glucagon on the timing and degree of hepatic enhancement at computed tomography. MATERIALS AND METHODS: Each of 11 dogs underwent injection of contrast material at two uniphasic rates (0.5 mL/sec and 1.5 mL/sec) with without previous intravenous administration of 0.5 mg of glucagon. Scans were obtained at a single intrahepatic level every 3.5 seconds for 120-160 seconds. Attenuation values in the liver, aorta, portal vein, and inferior vena cava (IVC) were measured. RESULTS: Glucagon administration was associated with greater hepatic enhancement throughout the study: Peak hepatic enhancement was greater at contrast injection rates of 0.5 mL/sec (P = .021) and 1.5 mL/sec (P = .0001). Peak hepatic enhancement also occurred earlier during the glucagon runs. Portal vein enhancement was greater during the glucagon runs at an injection rate of 1.5 mL/sec (P = .032). IVC enhancement was greater during the nonglucagon runs at 0.5 mL/sec (P = .013) and at 1.5 mL/sec (P = .005). CONCLUSION: Intravenous administration of glucagon before contrast material injection produces greater and more rapid hepatic enhancement in a canine model.
Subject(s)
Glucagon , Liver/diagnostic imaging , Radiographic Image Enhancement/methods , Tomography, X-Ray Computed/methods , Animals , Aortography , Blood Pressure , Contrast Media/administration & dosage , Dogs , Female , Glucagon/administration & dosage , Heart Rate , Injections, Intravenous , Liver/blood supply , Male , Pilot Projects , Portal Vein/physiology , Portography , Pulse , Regional Blood Flow , Time Factors , Vena Cava, Inferior/diagnostic imagingABSTRACT
PURPOSE: To describe the computed tomographic (CT) appearance of nodular hepatosplenic sarcoidosis and its association with stage with chest radiography and clinical status. MATERIALS AND METHODS: Thirty-two patients (21 women, 11 men; aged 25-68 years) with nodular hepatosplenic sarcoidosis were evaluated. CT findings were described along with chest radiographic stage, clinical status, and level of angiotensin-converting enzyme (ACE). RESULTS: Nodules were small, multiple, and of low attenuation. Organomegaly was common. Abdominal adenopathy was present in 76% of the patients. Chest radiographs were normal in 25%; 61% had stage 1 or 2 radiographs. Abdominal or systemic symptoms were present in 66%. ACE level was elevated in 10 (91%) of 11 patients tested. No change in chest radiographic stage was noted in 74% of patients with follow-up radiographs. CONCLUSION: Nodular hepatosplenic sarcoidosis is associated with organomegaly, adenopathy, and symptoms. Nodules were not associated with advanced lung disease and did not herald a change in chest radiographic stage. An elevated ACE level may be helpful in diagnosis.