It is estimated that nearly one-third of solitary pulmonary nodules (SPNs) may represent bronchogenic carcinoma. The noninvasive imaging methods used currently (ie, plain radiography, computed tomography) are not reliable for accurate detection of malignancy in most SPNs. The authors prospectively evaluated use of positron emission tomography (PET) with 2-[fluorine-18]-fluoro-2-deoxy-D-glucose (FDG) for identification of malignancy in 20 patients with noncalcific, radiographically indeterminate SPNs. PET-FDG imaging demonstrated focal hypermetabolism in 13 biopsy-proved malignant nodules, whereas no increased FDG uptake was seen in the seven benign SPNs. Semiquantitative analysis with computation of differential uptake ratios also helped clearly differentiate benign nodules (mean +/- standard deviation, 0.56 +/- 0.27) from malignant nodules (mean +/- standard deviation, 5.63 +/- 2.38) (P less than .001). Thus, PET-FDG imaging may be a potentially useful noninvasive technique for accurate differentiation of benign and malignant SPNs that are radiographically indeterminate.
The normal range of Doppler findings in native kidneys has not been studied extensively. This study correlates changes in Doppler resistive index (RI) Doppler arterial waveform analysis is based on the changes in flow velocity created by pulsatile arterial perfusion. The ratio of systolic to diastolic velocity is determined in large part by downstream resistance . 16 With increasing resistance, the diastolic velocity falls relative to the systolic value. The resistive index was designed as a mathematical index proportional to ar· terial resistance, and it equals the peak systolic frequency shift minus the peak end-diastolic shift divided by the peak systolic shift.
MATERIALS AND METHODSThis study consisted of two series of patients. In a small preliminary investigation, measurements were made to determine the spatial and temporal variability of serial waveforms obtained on a given kidney. Information from this pilot study was used to develop an efficient examination technique for the second, larger clinical study designed to evaluate normal age variation.The preliminary study examined 24 kidneys in 12 patients with no known renal disease. In these patients, three individual waveform measurements were made
The radiographic findings of post-transplantation lymphoma in 15 patients are demonstrated. Variations in patterns from those of lymphomas in nonimmunosuppressed patients, etiologic factors, histologic features, and differential diagnosis are discussed. The common finding of central lucency of masses seen on CT scans correlated with necrosis seen at histologic examination. In the post-transplant patient, single or multiple masses, particularly if centrally lucent, should suggest post-transplantation lymphoma. Histologic proof with anatomic localization is important, however, to determine appropriate therapy.
These preliminary results indicate that PET has increased sensitivity for staging colorectal carcinoma, whereas CT has higher specificity. The predictive value of a positive PET compares favorably with CT. Furthermore, the predictive accuracy for detection of colorectal carcinoma is 83 percent for PET and 56 percent for CT.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.