Diagnostic imaging of pneumonia and its complications in the critically ill patient.

Chest radiography and other radiographic imaging techniques often are extremely useful in the differential diagnosis of chest diseases in ICU patients. It should be remembered, however, that the findings on these imaging studies often are nonspecific. Also, different pathologic processes may be present in a patient's lungs at the same time. Clinical parameters, medical diagnostic studies, and laboratory studies are important in the differentiation of disease processes in these patients. The radiologist should work closely with the clinician to provide optimal care for patients in the ICU setting.

Magnetic resonance imaging of splenic hemangiomatosis.

The authors report a case of splenic hemangiomatosis evaluated by magnetic resonance imaging (MRI). Typical areas of hyperintensity were observed in T2-weighted images. Because it is noninvasive and highly sensitive, MRI proved valuable in suggesting the diagnosis in this patient.

Pneumonia and ARDS in patients receiving mechanical ventilation: diagnostic accuracy of chest radiography.

This study was done to evaluate the diagnostic accuracy of bedside chest radiography for pneumonia, adult respiratory distress syndrome (ARDS), or both in patients receiving mechanical ventilation. The series consisted of 40 patients; diagnostic accuracy was defined as the area under the receiver operating characteristic curve. Overall diagnostic accuracy for ARDS was 0.84. Overall diagnostic accuracy for pneumonia was 0.52. Review of previous radiographs and knowledge of clinical data did not enhance diagnostic accuracy for ARDS or pneumonia. Diagnostic accuracy for pneumonia was minimally reduced when ARDS was present. There was an increase in false-negative results because the diffuse areas of increased opacity in ARDS obscured the radiographic features of pneumonia. The authors conclude that chest radiography is of limited value for the diagnosis of pneumonia in patients receiving mechanical ventilation. The high false-negative and false-positive ratings for pneumonia resulted in a low diagnostic accuracy. The high diagnostic accuracy for ARDS was primarily due to the well-defined radiographic appearance of ARDS and few false-positive ratings.

Maximizing opacification during excretory urography: effect of low-osmolarity contrast media.

Because of improved patient tolerance and decreased risks of idiosyncratic reaction, low-osmolarity contrast media are increasingly used for excretory urography. However, physiologic differences among patients may affect the optimal time for acquiring diagnostic radiographs during the pyelographic phase of the examination. A prospective, randomized, physician-blinded comparative study of 60 adult patients was undertaken to determine if the time to peak opacification of the pyelocaliceal systems differs with different doses of nonionic and ionic contrast media. Three doses of contrast media were used: a high dose (based on body weight) of a high-osmolarity ionic contrast medium, a high dose (based on body weight) of a low-osmolarity non-ionic contrast medium and a lower, fixed dose of a low-osmolarity nonionic contrast medium. The diagnostic quality of the radiographs did not differ statistically with the dose or the contrast medium. However, acquiring an additional radiograph during abdominal compression greatly increased the chance of obtaining at least one radiograph with maximal diagnostic information during the pyelographic phase. Despite potential differences among contrast media in the degree of pyelocaliceal opacification or distension and diuresis, it is not necessary to modify the timing of film acquisitions during excretory urography when lower doses of low-osmolarity agents are administered.

Diagnostic efficacy of excretory urography with low-dose, nonionic contrast media.

A prospective, randomized, physician-blinded study was conducted to determine whether a smaller dose of low-osmolar, nonionic contrast medium can provide diagnostic information on excretory urograms equivalent to that obtained with higher doses of ionic and nonionic contrast agents. One hundred fifty adult patients who underwent excretory urography received a high-dose ionic contrast medium (diatrizoate sodium), high-dose nonionic contrast medium (iohexol), or low-dose nonionic contrast medium (iohexol). All urograms were scored for diagnostic quality. No difference in urographic quality was detected among the different doses of contrast media. The lower dose of low-osmolar nonionic contrast medium provided equivalent diagnostic information. The quality of the nephrotomograms, ureteral image, and overall image was slightly greater with diatrizoate than with a small dose of iohexol, but the difference was not significant. This study suggests that excretory urograms obtained in relatively healthy, well-prepared patients with smaller, less expensive doses of a nonionic contrast agent are at least diagnostically equivalent to those obtained with typical higher doses of ionic and nonionic agents.

Isolated left thoracic isomerism.

Left thoracic isomerism may present as an isolated anomaly without symptoms. The chest radiograph demonstrates characteristic right hilar findings that may be misinterpreted as a hilar mass. Computed tomography of the chest is recommended to confirm the correct diagnosis.