Detection of masses and clustered microcalcifications on data compressed mammograms: an observer performance study.

OBJECTIVE: To evaluate observers' ability to detect breast masses and clustered microcalcifications depicted on data compressed mammograms, an observer performance study was performed. MATERIALS AND METHODS: Eight observers assessed 60 mammographic images obtained in six modes, ranging from noncompressed to a maximum data compression level of 101:1. Observers were asked to rate the images on a scale of 0 to 100 for the likelihood of the presence of a mass and also independently for the likelihood of the presence of clustered microcalcifications. In addition, observers were asked to rate their subjective assessment of the quality of each image for the detection of a mass and separately for the detection of microcalcifications. Receiver operating characteristic analyses were performed. RESULTS: The average area under the receiver operating characteristic curve, A(z), for the detection of clustered microcalcifications decreases significantly at the highest data compression level when compared with the noncompressed and two lowest levels of data compression (p < 0.01), and a trend test of the average area under the receiver operating characteristic curve for all observers is statistically significant (p < 0.05). No statistically significant differences among or between any of the data compression level modes for the detection of masses were detected. CONCLUSION: At a high level of mammogram data compression, observer performance was degraded for the detection of clustered microcalcifications. Detection of masses was not affected by the data compression methods and levels used in this study.

Use of preoperative MR imaging in the management of endometrial carcinoma: cost analysis.

PURPOSE: To compare the cost of magnetic resonance (MR) imaging and its ability to direct the use of lymph node dissection with the cost and ability of conventional surgery for the staging of endometrial carcinoma. MATERIALS AND METHODS: Preoperative MR images of 25 patients who underwent hysterectomy for endometrial carcinoma were retrospectively evaluated. MR imaging results were compared with those of intraoperative gross dissection of the uterus and final histopathologic examination. Medicare reimbursements for two scenarios were compared in each patient. In the MR imaging scenario, the necessity for lymph node dissection was based on MR imaging results and histologic findings at biopsy. In the actual scenario, lymph node dissection was performed at the surgeon's discretion on the basis of findings at gross dissection of the uterus and histologic examination at biopsy. RESULTS: The cost of the MR imaging scenario, as defined by Medicare reimbursements, was 1% ($1, 265/$148,500) less than that of the actual scenario. In the MR imaging scenario, all patients who required lymph node dissection received it, and 86% of the lymph node dissections performed were necessary. In the actual scenario, one necessary lymph node dissection was not performed, and only 31% of the lymph node dissections performed were necessary. CONCLUSION: Staging with MR imaging has costs and accuracy similar to those of the current method of staging with intraoperative gross dissection of the uterus. In addition, MR imaging decreases the number of unnecessary lymph node dissections.

Observer sensitivity to small differences: a multipoint rank-order experiment.

OBJECTIVE: To evaluate observer sensitivity to small differences in image presentation, a multipoint rank-order experiment was used to identify small differences or trends in observations. MATERIALS AND METHODS: Ten observers were presented with 50 sets of breast images that had been compressed at five different levels. Each set contained six images ranging from noncompressed to approximately 101:1 compression. Observers were asked to review all images of a case side by side and rank order the quality of each to enable determination of the presence or absence of masses and clustered microcalcifications. RESULTS: As a group, observers were able to detect small differences among the images, even at the lower compression levels (p < .001). As compression levels and image degradation increased, the ability to identify differences between different modes also increased. Large observer variability in discrimination ability was observed. CONCLUSION: Multipoint rank ordering of images viewed side by side can be an efficient method to identify small differences in image presentation. This approach to image ranking could be used to rule out or confirm the need for objective observer performance-type studies.

Immunomodulatory properties of antineoplastic drugs administered in conjunction with GM-CSF-secreting cancer cell vaccines.

Cancer cells genetically modified to secrete immunoregulatory cytokines offer great promise for human cancer treatment as tumor vaccines. However, in preclinical animal studies, large established cancer burdens have appeared difficult to eradicate with such vaccines. For example, lethally-irradiated GM-CSF-secreting CT26 colon carcinoma cell vaccine therapy tends to cure only animals bearing 1 x 10(5) wild-type CT26 cells or less. For many human cancers, antineoplastic chemotherapy can often significantly reduce systemic cancer burdens. Unfortunately, for most advanced metastatic solid organ cancers, such as cancers of the breast, colon, and prostate, antineoplastic drug treatments generally fail to effect cancer cures. Treatment regimens combining genetically-modified cancer cell vaccine therapy and antineoplastic chemotherapy have the potential to increase advanced cancer cure rates if antineoplastic drugs and drug combinations that do not inhibit vaccine-induced immune responses can be identified. To assess the potential immunomodulatory properties of commonly-used antineoplastic drugs that might be used in combination with cancer vaccine treatments, we studied the effects of the drugs on antitumor immune responses manifest by animals receiving lethally-irradiated GM-CSF-secreting CT26 cell vaccines. Immunomodulatory properties of the antineoplastic drugs were evaluated i) by monitoring drug effects on the generation of tumor-specific CD8+ cytotoxic T-lymphocytes (CTLs) in response to GM-CSF-secreting CT26 vaccine administration, ii) by determining drug effects on the resistance of vaccinated animals to subsequent challenge with lethal inoculac of CT26 cells, and iii) by evaluating combination drug and vaccine treatment efficacy against established CT26 tumors. Using this approach, doxorubicin was found to possess apparent immunostimulatory activities, depending on the dose and schedule of administration, while cyclophosphamide appeared immunosuppressive. The different immunomodulatory properties of doxorubicin and cyclophosphamide may be clinically relevant: combination doxorubicin and vaccine treatment of established CT26 cancers increased cure rates over that achieved with either agent alone, while combination cyclophosphamide and vaccine treatment of animals carrying CT26 tumors was no better in curing the animals than drug treatment alone.

Preliminary clinical evaluation of a high-resolution telemammography system.

RATIONALE AND OBJECTIVES: The authors designed, assembled, tested, and clinically evaluated a high-quality, fast, and relatively inexpensive telemammography system. METHODS: The authors designed a telemammography system that uses a high-resolution film digitizer and high data compression (> or = 40:1) to send images over regular telephone lines to a high-resolution laser printer that produces images with the look and feel of the original image and can operate in a hub and spokes mode. The authors then evaluated the system's performance. In a preliminary clinical study, interpretations of the laser-printed system's output of 119 cases were compared with the original interpretations, followed by a review of any clinically significant differences. RESULTS: With the exception of the laser printer, which is a modified off-the-shelf product, all hardware components of the system are commercially available products. The system digitizes (50 microns pixel size), compresses, transmits, receives, decompresses, and prints a 30 MB mammography file in less than 4 minutes. In the clinical study, there were 13 differences (in 13 cases) in the level of concern or recommendations. Seven were found to be clinically insignificant by a third-party review. The remaining six were reviewed by the original interpreter, and three were determined to be significant enough for further action. All were found to result from intra-reader variability rather than differences in visualization of possible abnormalities. CONCLUSIONS: Almost real-time, high-quality telemammography without geographic boundaries is possible with the use of high-level data compression. Telemammography with laser-printed film as the display may make it possible to offer mammographic services in remote locations while using commercially available technology.

Contemporary radiologic percutaneous abscess drainage in the pelvis.

In summary, PAD of pelvic abscesses is an established radiologic procedure. The procedure has gained wide acceptance as an adjunct in the management of patients with pelvic abscess. The procedure involves minimal trauma, is well tolerated, and produces early relief of symptoms. In many instances, it may shorten the length of the hospital stay, reduce costs, and often eliminate the need for surgical intervention. In selected patients, PAD may serve as a temporizing measure in a critically ill or endstage patient. Initial results of PAD treatment of TOA are encouraging, suggesting that this procedure, just as elsewhere in the abdomen, is safe and effective, but larger series are required and long-term follow-up is necessary for evaluation of the cure rate, rate of recurrence, and possible complications.

US-guided venipuncture for venography in the edematous leg.

A technique for sonographic-guided venipuncture was developed especially for venography made difficult by gross leg edema. Five patients were evaluated in whom venography had been attempted but was initially unsuccessful because of difficult venous access. All five underwent successful venipuncture after sonographic localization of a vein. Ultrasound-guided venipuncture is simple and useful when venous access by palpation is difficult.