In vitro activity of moxifloxacin(BAY 12-8039) against respiratory tract pathogens from six Latin-American countries.

The in vitro antibacterial activity of moxifloxacin (BAY 12-8039) was evaluated against 636 isolates of respiratory tract pathogens. The isolates were collected from July 1997 to August 1998 in the frame of a multinational Latin American study. E-test strips calibrated to read moxifloxacin MIC ranges from 0.002 to 32 microg/ml were used in susceptibility testing. Weekly quality control tests in each laboratory ensured reproducibility. Laboratories from Argentina, Brazil, Chile, Colombia, Mexico and Uruguay participated. MIC(90) for moxifloxacin were as follows: Streptococcus pneumoniae (304 isolates) 0.25 microg/ml, Haemophilus influenzae (135 isolates) 0.125 microg/ ml, Streptococcus pyogenes (66 isolates) 0.25 microg/ml, Moraxella catarrhalis (62 isolates) 0. 25 microg/ml and methicillin-sensitive Staphylococcus aureus (69 isolates) 0.25 microg/ml. These results agreed with reports from other areas. Moxifloxacin showed excellent activity against respiratory pathogens from participant countries.

Comparing the performance of mammographic enhancement algorithms: a preference study.

OBJECTIVE: The objective of this study was to compare the performance of four image enhancement algorithms on secondarily digitized (i.e., digitized from film) mammograms containing masses and microcalcifications of known pathology in a clinical soft-copy display setting. MATERIALS AND METHODS: Four different image processing algorithms (adaptive unsharp masking, contrast-limited adaptive histogram equalization, adaptive neighborhood contrast enhancement, and wavelet-based enhancement) were applied to one image of secondarily digitized mammograms of forty cases (10 each of benign and malignant masses and 10 each of benign and malignant microcalcifications). The four enhanced images and the one unenhanced image were displayed randomly across three high-resolution monitors. Four expert mammographers ranked the unenhanced and the four enhanced images from 1 (best) to 5 (worst). RESULTS: For microcalcifications, the adaptive neighborhood contrast enhancement algorithm was the most preferred in 49% of the interpretations, the wavelet-based enhancement in 28%, and the unenhanced image in 13%. For masses, the unenhanced image was the most preferred in 58% of cases, followed by the unsharp masking algorithm (28%). CONCLUSION: Appropriate image enhancement improves the visibility of microcalcifications. Among the different algorithms, the adaptive neighborhood contrast enhancement algorithm was preferred most often. For masses, no significant improvement was observed with any of these image processing approaches compared with the unenhanced image. Different image processing approaches may need to be used, depending on the type of lesion. This study has implications for the practice of digital mammography.

Clinical evaluation of wavelet-compressed digitized screen-film mammography.

RATIONALE AND OBJECTIVES: The authors compared diagnostic accuracy and callback rates with conventional screen-film mammograms and wavelet-compressed digitized images. MATERIALS AND METHODS: Sixty sets of mammograms (four views per case) were digitized at a spatial resolution of 100 microm. The images were wavelet compressed to a mean compression ratio of 8:1 and reviewed by three mammographers. Five regions were evaluated in each breast. Suspicion of malignancy was graded on a scale of 0% to 100%, and receiver operating characteristic (ROC) analysis was performed. Callback rates were calculated by using the American College of Radiology's Breast Imaging Reporting and Data System lexicon scale. RESULTS: The mean diagnostic accuracy with compressed and conventional images was 0.832 and 0.860, respectively. The upper 95% confidence bound for the difference in ROC areas was 0.061. The mean false-positive rate at a fixed sensitivity of 0.90 was 0.041 for compressed images and 0.059 for conventional images. The mean callback rates for normal, benign, and malignant regions were 0.023, 0.305, and 0.677, respectively, for compressed images and 0.036, 0.447, and 0.750, respectively, for conventional images. The upper 95% confidence bound for the (absolute) differences in callback rates was 0.012 for normal regions, 0.163 for benign regions, and 0.138 for malignant regions. CONCLUSION: Diagnostic accuracies were equivalent for both compressed and conventional images. The mean false-positive rate at fixed sensitivity was much better with the compressed images. However, the callback rates for malignant lesions were lower when the compressed images were used.

How new technology is changing mammography and breast cancer management.

Breast-imaging technology has improved in ways that allow one not only to detect breast cancer earlier, but also to distinguish benign from malignant lesions better. These capabilities are influencing the approach to breast cancer. We review current trends and issues for the non-radiologist.

Film-screen versus digitized mammography: assessment of clinical equivalence.

OBJECTIVE: The purpose of this study was to determine whether diagnostic accuracy and callback rates using digitized film images are equivalent to those using film-screen mammograms. MATERIALS AND METHODS: Sixty sets of mammograms (four views per case) were digitized at a spatial resolution of 100 microm. The images were reviewed by seven mammographers. Five regions were evaluated in each breast. Each region was scored on a scale of 0 100% for suspicion of malignancy, and a receiver operating characteristic analysis was performed. Callback rates were calculated using a published lexicon scale. RESULTS: The observers' mean diagnostic accuracies using films and digitized images were 0.872 and 0.848, respectively. The upper 95% confidence boundary on the difference in accuracy was 0.066. The mean callback rate for normal, benign, and malignant areas using films versus digitized images was 0.048 versus 0.055, 0.498 versus 0.441, and 0.786 versus 0.737, respectively. The upper 95% confidence boundary for the absolute difference in callback rates was 0.037, 0.026, and 0.130 for normal, benign, and malignant areas, respectively. CONCLUSION: The diagnostic accuracies of the digitized images and films were similar; however, an increase in callback rates of 0.037 (i.e., upper 95% confidence boundary) for normal results and a reduction in the callback rates of 0.130 for malignant lesions is important. The use of digitized film images, at a spatial resolution of 100 microm, may compromise patient treatment in clinical practice.

Mammographic halo sign revisited.

PURPOSE: To determine whether increased silver halide deposition accounts for some curvilinear areas of hyperlucency (halo signs) that surround breast masses on screen-film mammograms. MATERIALS AND METHODS: Breast images obtained in 43 women (aged 30-67 years; mean, 48.6 years) that showed a halo sign were selected from the authors' teaching files. Optical magnification (x8.0-12.5) of the masses with halos was used to establish the pattern of silver halide deposition in the film emulsion. RESULTS: True radiolucent halos, differentiated from Mach bands by means of the increased silver halide deposition in the film emulsion, were identified in 44 masses in 36 women. Partial true radiolucent halos were identified in 32 (73%) of 44 masses. Thirty-eight (86%) of the 44 masses were cysts; three (7%), fibroadenomas; two (4%), infiltrating ductal carcinomas; and one (2%), axillary lymph node metastasis. True radiolucent halos were more common in growing benign and malignant lesions. CONCLUSION: A halo is not always a perceptual illusion.

Percutaneous large-core breast biopsy: a multi-institutional study.

PURPOSE: To assess the reliability and reproducibility of automated large-core breast biopsy. MATERIALS AND METHODS: A consortium of 20 institutions reported, in a standardized fashion, their core breast biopsy data. All biopsies were performed with "long-throw" (2.3-cm) automated core biopsy devices fitted with 14-gauge needles. Needle guidance was accomplished by means of either a dedicated, stereotaxic device, in which the patient lies in the prone position, or high-frequency electronically focused ultrasound equipment. RESULTS: The data in 6,152 lesions were gathered. Clinical or surgical follow-up was available in 3,765 lesions; 1,363 of these lesions were subsequently surgically excised, and the core histologic study showed cancer in 910 lesions, mammary intraepithelial neoplasia in 173 lesions, and benign disease in 280 lesions. In these 280 lesions, there were 15 false-negative core biopsies. CONCLUSION: The data show that percutaneous large-core breast biopsy is a reproducible and reliable alternative to surgical biopsy.

Mucinous (colloid) breast cancer: clinical and mammographic findings in 10 patients.

OBJECTIVE: The purpose of this study was to review the clinical and mammographic findings in patients with mucinous (colloid) breast cancer. MATERIALS AND METHODS: We retrospectively reviewed the pathology reports of 444 women with breast cancers diagnosed between May 1988 and October 1993 after mammographic evaluation. Of these, 10 women 31-88 years old (mean, 67 years) had pure mucinous adenocarcinoma of the breast. We reviewed the clinical and mammographic findings in these 10 patients. RESULTS: Three patients (30%) had palpable masses. Mammographic abnormalities were detected on screening studies in the seven patients (70%) who were asymptomatic. The mammographic findings included poorly defined, lobulated, solitary masses in seven patients, poorly defined, clustered masses in two patients, and a well-circumscribed mass in one patient. No tumors had calcifications as the primary finding, and only one tumor had a few scattered, round, calcifications associated with clustered masses. Two patients had areas of noncomedo ductal carcinoma in situ without calcifications adjacent to the invasive mucinous adenocarcinoma. The tumors were 7-35 mm in diameter. No metastases were found in the axillary lymph nodes in the eight patients in whom biopsies of these nodes were done. CONCLUSION: The most common and distinctive mammographic feature of mucinous breast carcinoma is a poorly defined, lobulated mass. The absence of axillary nodal metastases, even in patients with large palpable tumors, supports the notion that biologically, mucinous carcinomas are slower growing, less aggressive tumors than infiltrating ductal carcinomas not otherwise specified.

Ductography of the breast: technique and findings.

The evaluation of spontaneous nipple discharge is controversial. Many surgeons advocate major subareolar duct excision for postmenopausal patients or solitary duct excision for premenopausal women with this symptom, without preoperative diagnostic imaging. There is no dispute that as a symptom, nipple discharge can be eliminated by severing the major subareolar ducts. However, this decision requires generous assumptions on the part of the surgeons: first, that the abnormal duct can be identified correctly; second, that the segmental area or areas of the breast drained by the duct can be predicted accurately; and third, that the amount of tissue that needs to be excised to ensure inclusion of the lesion or lesions can be defined. Ductography can show the course of abnormal ducts, as well as the variability in location and extent of intraductal lesions. Preoperative mapping of the abnormal duct can expedite surgery, facilitate accurate minimal-volume breast biopsies, and alert the surgeon to the existence of an extensive ductal lesion or multiple lesions. In patients with fibrocystic changes or duct ectasia on ductography, surgery might be averted altogether. In an effort to demonstrate the usefulness of ductography and encourage its increased use, we review the technique and illustrate normal and abnormal findings.