Having adjusted the region/area of interest, angle of acquisition, and quality, acquisition is started. Higher quality takes longer time to acquire as it contains more B-mode frames in the volume block, whereas lower quality volume takes shorter time to acquire. Quality of the volume is selected depending on whether the structure or organ of interest is steady and stable or has movements. To select the volume angle, probe is manually angulated up and down or side to side depending on orientation of the image to assess the depth the organ of interest. The volume box should be large enough to include the area of interest with at least 5–10 mm of margin on all sides.
The volume box is switched on and is placed over the area of interest. This area should ideally be placed in the center of the monitor screen. The area of interest is first selected on the B-mode scan. This means that the structures that are not in the center of the image field are hit by the sound waves tangentially and therefore lead to hazy or unsharp margins of those structures. This means that when sound beam is emitted from the convex probe surface, the sound beam is vertical in the central part but is oblique on the sides. The sound beam from the transducer head is emitted perpendicular to the transducer surface. There is another advantage of decreasing the scanning angle once the structure of interest is located. Narrowing the scanning angle increases frame rate, therefore results in better resolution image ( Fig. Therefore, once the area of interest has been located, the scanning angle should be narrowed down to just a little larger than the area of interest. This means that if the frame rate is low, the image resolution is low, it appears less clear and reveals fewer details. Frame rate is the number of static images captured in a unit time by the scanner. Faster the change in frames, more real time it looks. It is known that the real time B-mode images that we are seeing on the scanner screen appear continuous because of several static images seen quickly one after the other. 1.9A), but it decreases the speed of scanning which is indicated by frame rate. Large scanning angle is very convenient for obtaining the bird's eye view of the pelvis ( Fig. Maximum scanning angle for transvaginal probes usually vary from 80 to 180°. It indicates as to how much area can be covered by a single US beam or how far sideward can an US beam see. This is the maximum angle up to which the US beam can fan out.
Counseling the patient before examination and explaining the whole procedure helps eliminate the anxiety and resistance.Įach probe has a maximum scanning angle. A small amount of jelly is then placed over the condom on the probe head, and the probe is gently slided into the patient's vagina ( Fig. US jelly is put on the head of the transvaginal probe, and then the probe is covered with the condom, not leaving any air between the probe and the condom.
But with this position also, the probe movement is restricted, and the comfort of the examination is not sufficient. A pillow under the patient's buttocks may help to raise the buttocks if the scan is done on flat bed. Gynecology couch, as it has a gap in the center, allows easy probe movements ( Fig.
Maintaining privacy and dignity of the patient is of utmost importance. 1.2) on the gynecology couch in the same way as for per speculum or per vaginal examination and is adequately covered with a clean sheet, so that she does not feel uncomfortable. Patient is undressed, placed in lithotomy-like position ( Fig. At least a verbal consent of the patient is essential.
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