Studies suggest that screening with spiral computed tomography can detect lung cancers at a smaller size and earlier stage than chest radiography can. To evaluate low-radiation-dose spiral computed tomography and sputum cytology in screening for lung cancer, we enrolled 1,520 individuals aged 50 yr or older who had smoked 20 pack-years or more in a prospective cohort study. One year after basel...

Computed tomographic (CT) imaging involves exposure to ionizing radiation, with a consequent potential risk to the patient. Here we review the technical factors that affect the radiation dose in cardiac CT diagnostic procedures, the parameters that are used to measure and compare radiation doses, the magnitude of radiation exposure, and how to efficiently reduce it.

OBJECTIVES To assess the capability of spiral computed tomography (CT) scan in preoperative evaluation of colorectal carcinoma (CRC). METHODS A cross sectional study on 52 patients with recent histopathologic diagnosis of CRC was conducted over a period of one year at the Aga Khan University Hospital, Karachi. All these patients underwent spiral CT with oral and intravenous contrast administr...

We read with interest the article by Dr Chang and colleagues 1 in CHEST (January 2013) about the management of ground-glass opacities (GGOs). Their data indicate that the strategy of longterm follow-up and selective surgery was appropriate. However, we do not entirely agree with their ideas. We offer a third choice of CT scan-guided biopsy to solve the long-standing issue. Previous studies have...

A 3π algorithm is obtained in which all the derivatives are confined to a detector array. Distance weighting of backprojection coefficients of the algorithm is studied. A numerical experiment indicates that avoiding differentiation along the source trajectory improves spatial resolution. Another numerical experiment shows that the terms depending on the non-standard distance weighting 1/|x − y(...

The accuracy of computed tomography (CT) imaging for the diagnosis of acute pulmonary embolism (PE) was reviewed. Single detector CT, based on pooled data, showed a sensitivity of 73% and multidetector CT, mostly 4-slice, showed a sensitivity of 83%. Respective specificities were 87% and 96%. Among patients with suspected PE evaluated with single slice CT, 20% of patients found to have venous t...