Cleaning methods for ultrasound probes

To determine the effectiveness of three different methods of ultrasound probe cleaning for the prevention of nosocomial infections. Experimental study. Radiology Department, the Aga Khan University Hospital, Karachi and Microbiology Department, JPMC, Karachi, from December 2006 to April 2007. A total of 75 culture swabs from ultrasound probes used for sonographic examinations of different body parts of patients were included in the study. Probes were prospectively randomized into three equal groups with 25 probes in each group. Culture was sent before and after using three different techniques of cleaning ultrasound probe, which included sterilized paper towel, 0.9% saline and swipe over with standard bath soap applied on group A [n = 25], group B [n = 25] and group C [n = 25] respectively. Number of Colony Forming Unit [CFU] of bacteria were calculated on standard agar plate to find out the effectiveness of cleaning methods in reducing bacterial count from the ultrasound probe after the procedures. All samples were tested in single microbiology lab by using same bacterial growth media provided by same manufacturer. Kruskall Wallis, Jonchkheere-Terpstra and Wilcoxon sign rank tests were applied to find out statistical significance. There was a significant reduction in bacterial count after applying either of all three cleaning methods for ultrasound probe compared to count on the probes before cleaning [p < 0.001], however, soap cleaning method was the most effective in decreasing bacterial count to the minimum level in comparison to other two methods [p < 0.001]. The overall reduction in pathogenic bacterial count after performing each cleaning method was 45%, 76% and 98% for paper cleaning, normal saline and soap cleaning method respectively. Cleaning ultrasound probe after performing each procedure is a cost-effective practice with potential of reducing nosocomial infections. Soap cleaning technique is the most effective method for reducing bacterial count acquired due to patients' body contact with the ultrasound probes

Mammographic criteria for determining the diagnostic value of microcalcifications in the detection of early breast cancer

Objective: To evaluate the importance of microcalcifications in the detection of breast carcinoma in conventional mammography

Material and Methods: This prospective study was carried out at Aga Khan University Hospital [AKUH]. Mammograms of 68 patients with microcalcifications were evaluated. Craniocaudal and oblique views of both breasts were acquired on routine basis with cone compression and magnified views when required

Results: Among 68 patients with microcalcifications, 61 [89%] had clustered microcalcifications while 7 patients [10.29%] had scattered microcalcifications. Microcalcifications can occur in benign and malignant diseases. While evaluating clustered microcalcifications, few criteria have been established to determine malignant clustered microcalcifications, these include specific and nonspecific criteria. Among specific and statistically significant criteria for malignant microcalcifications, which were identified in this study, were irregularity of size, irregularity of density, linear or branched shape and Le Gal's type V distribution. In a cluster total number of >30 microcalcifications and at least 10 microcalcifications/cm2 of a cluster are also important in diagnosing a malignant cluster, but are included in nonspecific criteria because they can be present in benign diseases also. Scattered bilateral microcalcifications are usually present in benign breast diseases, but in this study, two patients with breast cancer had profuse bilateral scattered microcalcifications

Conclusion: This study shows that specific and statistically significant criteria for malignant microcalcifications, are irregularity of size, irregularity of density, linear or branched shape and Le Gal's type V distribution. Scattered bilateral microcalcifications are usually present in benign breast diseases, but irregular shape and development of new calcifications among diffusely scattered bilateral calcifications, on follow up study, should also raise suspicion for being malignant