Determination of Optimal Imaging Mode for Ultrasonographic Detection of Subdermal Contraceptive Rods: Comparison of Spatial Compound, Conventional, and Tissue Harmonic Imaging Methods

OBJECTIVE: To determine which mode of ultrasonography (US), among the conventional, spatial compound, and tissue-harmonic methods, exhibits the best performance for the detection of Implanon(R) with respect to generation of posterior acoustic shadowing (PAS). MATERIALS AND METHODS: A total of 21 patients, referred for localization of impalpable Implanon(R), underwent US, using the three modes with default settings (i.e., wide focal zone). Representative transverse images of the rods, according to each mode for all patients, were obtained. The resulting 63 images were reviewed by four observers. The observers provided a confidence score for the presence of PAS, using a five-point scale ranging from 1 (definitely absent) to 5 (definitely present), with scores of 4 or 5 for PAS being considered as detection. The average scores of PAS, obtained from the three different modes for each observer, were compared using one-way repeated measure ANOVA. The detection rates were compared using a weighted least square method. RESULTS: Statistically, the tissue harmonic mode was significantly superior to the other two modes, when comparing the average scores of PAS for all observers (p < 0.00-1). The detection rate was also highest for the tissue harmonic mode (p < 0.001). CONCLUSION: Tissue harmonic mode in uS appears to be the most suitable in detecting subdermal contraceptive implant rods.

Similarity of bone mass measurement among hip, spines and distal forearm.

From January-December 1995, bone mineral density (BMD) of lumbar spine, hip and distal forearm were studied in 325 healthy women visiting the menopause clinic, Chulalongkorn Hospital. This retrospective analysis was conducted to assess the correlation of BMD among various measurement sites. Bone mass measurement at hip and spine were performed utilizing dual energy X-ray absorptiometer (DEXA), Hologic QDR 2000 and at distal forearm by single energy X-ray absorptiometer (SEXA), Hologic DTX 100. By canoconical correlation, the results revealed a significant correlation of BMD of distal and ultra-distal part of forearm with various sites of hip (r = 0.602, p < 0.001). There was also significant correlation of distal and ultra-distal part of forearm with various sites of spines (r = 0.619, p < 0.001). Though there is some heterogeneity of bone mass density among different measurement sites, practically with this fairly good level of correlation, bone mass measurement of distal forearm might be used to predict the BMD of hip and spine in Thai women. The accuracy of predicting the BMD of hip and spine by BMD of distal forearm in the mass screening programme in Thailand is now going on. The results will be followed.