超聲診斷在婦科

資料來源::超聲診斷在婦科

For optimum ultrasonographic visualization, certain mechanical, physical, and ultrasonographic principles must be understood. The quality of an image ultimately depends on the degree of resolution. In general, the closer the transducer tip is to the imaging target, the greater the resolution, and, therefore, the clearer the image. Every effort must be made to avoid interference with transmission of ultrasonographic energy.11 A thorough understanding of the longitudinal (sagittal), cross-sectional (axial), and coronal anatomy of the pelvis is necessary for optimal image interpretation. Whereas scanning planes for transabdominal scanning are classically described as sagittal, axial, and oblique, the transvaginal approach offers the additional coronal scanning plane.12,13 Accurate orientation is a necessity for the appropriate interpretation of pelvic imaging. Because much of the imaging is performed with the use of “organ-specific” planes, the practitioner must be aware of the scanning orientation to achieve an accurate interpretation of the findings noted on the image.13

In addition to understanding the need for close approximation of the imaging target by the transducer, realize that the quality of the image is influenced by the frequency of the transducer, pulse repetition frequency, and image processing. For a more in-depth analysis of these imaging principles, the reader is referred to standard texts on ultrasonography.

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Leiomyoma.
Uterine enlargement that is not caused by pregnancy most often is a result of uterine leiomyomata. Uterine leiomyomata represent proliferations of smooth muscle and are benign neoplasms. Leiomyomata are classified by their location as subserous, intramural, or submucous. Ultrasonographically, leiomyomata exhibit poor sound transmission because much of the sonic energy is attenuated by the solid consistency of the mass. Uterine contour irregularity is one of the most consistent findings44; however, a variety of findings may occur.45 Ultrasonography offers the potential of measuring uterine leiomyomata in patients in whom a conservative or nonsurgical management plan is initiated46 (Figs. 22 and 23). In addition, ultrasonography may detect early signs of degeneration or calcification of uterine leiomyomata. The effect of gonadotropin-releasing hormone suppression of uterine leiomyomata is easily monitored by ultrasonography. Occasionally, leiomyomata may undergo degeneration and mimic other cystic pelvic masses.47,48
子宮肌瘤
子宮肌瘤是最常見不是懷孕所引起的子宮擴大的現象。 子宮肌瘤是平滑肌增生的良性腫瘤。 肌瘤按它們的位置，可以分類為子宮漿膜下肌瘤、子宮壁內肌瘤，或子宮粘膜下肌瘤。

在超音波診斷上，因為固體物質導致聲波能量的消弱（譯者注：子宮肌瘤為平滑肌組成，屬於固體物質，而不似一般妊娠超音波時羊水的液體狀態），因而呈現的回傳音量少，常見的診斷發現是子宮外觀輪廓呈現不整齊狀，然而也可能出現其它不同的診斷發現。超音波檢查可以用於判斷有子宮肌瘤的人，是否具備足夠條件，可以進行不需動手術、保守的身體管理計劃。除此之外，超音波檢查也可以偵測子宮肌瘤退化或鈣化的早期癥兆。藉由超音波檢查，極容易發現抑制促性腺激素分泌對子宮肌瘤的影響。偶爾，子宮肌瘤會惡化或成為其它類似骨盆腔的囊性腫塊。