The effect of clinical history on chest radiograph interpretations in a PACS environment.

The effect that accompanying patient information has on diagnostic accuracy in radiologic interpretation has been studied by many researchers but remains a matter of contention. Experiments in the past emphasized the chest film because this procedure is the one done most frequently in radiology. However, with the increasing importance of digital imaging, the role of patient history in these procedures should be assessed. The use of a model computerized patient history in the interpretation of digitized chest images that were displayed on a high-resolution workstation was studied. Two hundred forty-seven selected posteroanterior chest images that indicated disease and that indicated no disease were interpreted in random sequence by five board-certified radiologists, with and without accompanying patient histories. Readers were prompted by the response forms to evaluate images for the possible occurrence of interstitial diseases, nodules, or pneumothorax. No significant differences (P = .05) in the detection of these abnormalities were noted between case readings with and without history for any of the radiologists or for the group as a whole. However, this methodology reflects a direct interpretation approach. The results of this study may not necessarily be applicable to individual prompts, different imaging procedures, or other abnormalities.

Effect of two rating formats in multi-disease ROC study of chest images.

ROC methodology has been expanded in recent years to include multi-disease experiments. To accommodate these changes, different rating formats, general or disease specific, can be used. No experimental data are available concerning the possible effects of the rating format on the results of these studies. We performed a multi-observer, multi-disease study in which 196 chest images were rated using a format where each disease was evaluated individually and one in which the cases were evaluated without scoring a specific disease. The results indicate that for our data set, the overall assessment of accuracy was not significantly affected by the study format used. Thus, in spite of the difficulties in selecting appropriate controls and the necessity of reassessing sample size considerations, the disease-specific format appears to produce an assessment of accuracy equivalent to that produced by the general format. This equivalence permits the use of the disease-specific approach since it more closely simulates the readers' true environment and is more appropriate for comparing imaging systems that may have a relative accuracy that is disease specific.

MR of the salivary glands.

MR has become the examination of choice for imaging salivary gland neoplasms. The improved soft tissue contrast of MR represents a significant improvement over CT, particularly for extension outside the gland. The appearance of various tumors and inflammatory processes is described.

Magnetic resonance imaging of the paranasal sinuses.

MRI has been very helpful in evaluating tumors in the paranasal sinuses. MRI can differentiate retained secretions from tumors. The multiplanar capabilities of MRI are also very helpful in identifying tumor margins. Although a specific diagnosis can be suggested in most cases, demonstration of the extent of the disease and specifically the relationship to key surgical landmarks is more important. Structures of thin cortical bone are better seen with CT than MRI. For several reasons, CT is still the examination of choice for evaluation of the osteomeatal complex and inflammatory disease of the sinuses.

Sphenochoanal polyps: evaluation with CT and MR imaging.

A sphenochoanal polyp is a solitary mass of low attenuation on computed tomographic (CT) scans that arises from the sphenoid sinus and extends through the sphenoid ostium, across the sphenoethmoid recess, and into the choana (the boundary between the nasal cavity and nasopharynx). More often, however, a choanal polyp is an antrochoanal polyp, which arises from the maxillary antrum, protrudes through the middle meatus, extends into the nasal cavity, and continues back to the choana. Contiguous axial or coronal magnetic resonance and CT images help clearly differentiate the rare sphenochoanal polyp from the more common antrochoanal polyp. The sinus of origin is important to identify, as the surgical approach depends on the target sinus.

Dehiscent temporomandibular joint.

The appearance of an acute effusion in a well-pneumatized temporal bone directs attention to the nasopharynx and skull base. Two patients are described in whom dehiscence of the temporomandibular joint allowed herniation of the contents of the joint posteromedically, where they obstructed the middle ear entrance of the eustachian tube, the protympanum. This is, to the authors' knowledge, a previously unreported cause of an acute middle ear and mastoid effusion.

Osteogenesis imperfecta tarda: appearance of the temporal bones at CT.

The computed tomographic findings in the temporal bone of two patients with osteogenesis imperfecta tarda are described. One of the patients had bilateral facial nerve paresis, and both patients presented with hearing loss.

Three-dimensional computed tomography.

Three-dimensional images were generated by reformating data from an axial image set. Separate contours were generated for bone and for tumor. The contour representing the tumor was generated by tracing the tumor using a cursor on the CRT. The contours showed the relationship of the tumor to the skull base. Three-dimensional imaging by this method is more of a communication tool than a diagnostic tool. The information on such images can be derived from close analysis of the axial image set. Indeed, determination of the position of the tumor relative to very precise structures requires analysis of the original images. The three-dimensional imaging does orient the observer and give an overall view of the position of the tumor. Because the contour of the tumor is traced, the final image represents the opinion of the radiologist. Various technical considerations and artifacts are discussed.