Case reviews 166–184

Fig. 359 . Topic: Anal Sphincter Complex (ASC) Color Power Doppler Pulse Repetition Frequency Settings.

Pulse repetition frequency (PRF) indicates the number of ultrasound pulses emitted by the transducer over a designated time frame. It is typically measured as cycles per second or hertz (Hz). The PRF is operator dependent. When using Color Power Doppler, the PRF knob should not be set too low, otherwise image pixels will demonstrate a “blush” to the entire color box, misgauging “flow” where there is none (screen left). Contrarily, if the PRF is set too high, real vascularity will not be present on an image at all, which will underestimate the presence of any vessels and will certainly underrepresent abnormal vascularity (screen right). When the PRF is set appropriately, clear presence of real abnormal flow will be seen (gold arrow).

Though the presence of the correctly placed intrauterine device (IUD) is easy to visualize, there is a wide variability in actual IUD location when comparing exams. Figs. 360–362 are each a different IUD case.

Fig. 360 is a 3D volume set using a 6–12 MHz endovaginal (EV) transducer with a rendered image of a recently placed IUD. Answer the following with a Yes or No.

• a.

  Is the stem located centrally? _____

• b.

  Are the arms contained within the endometrial cavity? _____

• c.

  Is the uterus retroverted? _____

• d.

  Is the center reference point seen on all planes with the green line of reference (LOR) at the 
appropriate place to optimize the IUD on the rendered image? _____

Fig. 361 is a 3D volume set using a 5–9 MHz EV transducer of a postpartum patient who is highly anxious that her recently placed IUD may not be present. Answer the following.

• e.

  Where is the center reference point placed on the volume set to assess the IUD placement? _____

• f.

  Is the IUD placed centrally? _____

• g.

  To what on the C plane are the green arrows pointing? _____

Fig. 362 is a 3D volume set on a patient with pelvic discomfort since her IUD was placed. The rendered image has been removed. Which of the following is where the center reference point is placed on the volume set?

• a.

  It is placed to the right of the midline (ML) 
central cavity within the right submucosal 
myometrium.

• b.

  It is placed to the left of the ML central cavity within the left submucosal myometrium.

• c.

  It is placed within the central endometrial cavity.

• d.

  It is placed within the intramural myometrium anterior to the endometrium.

Fig. 362 . Is the IUD placed centrally within the 
endometrial cavity?

• a.

  Yes

• b.

  No

• c.

  Cannot tell from these images

Figs. 363–365 are images, using a 5–9 MHz EV transducer, of a 33-year-old patient found to have pelvic fullness at her annual exam.

• a.

  Which ovary has a normal parenchymal echo pattern? _____

• b.

  Which ovary has abnormally increased size? _____

• c.

  Which ovary has normal follicular appearance? _____

• d.

  Which ovary has an irregular contour? _____

Color Power Doppler hypervascularity is well 
visualized on Figs. 364 and 365 of the right ovary. The resistive index at this area (not shown) was 0.71. Is hypervascularity increased at the intraovarian parenchyma or at the hilum? _____

Of the following, which is the least likely diagnosis for this appearance?

• a.

  Ovarian carcinoma

• b.

  Polycystic ovarian syndrome

• c.

  Dysgerminoma tumor

• d.

  Sertoli–Leydig cell tumor