Obs (transvag)

Question 1

Type de sonde?

Answer 1

endocavitaire/transvaginale

Question 2

Préparation de la pte?et de la sonde?

Answer 2

Patient positioning
Lithotomy either in gynecology bed or with pelvis elevated on pelvic pillow.

Patient draping
Sheet covering patient from abdomen to below knees, raised above knees to expose introitus for probe insertion only, then replaced to below knees.

Probe orientation
Sagittal – Probe held parallel to stretcher / floor with the beam directed towards the patient’s head and the probe marker oriented towards the ceiling.

Coronal – Probe held parallel to stretcher / floor with the beam directed towards the patient’s head and the probe marker oriented towards patient right.

Probe grip
Sagittal/Coronal – Probe held with thumb on indicator and 2nd +/- 3rd fingers on opposite side as if holding a pistol.

Question 3

repère externe?

Answer 3

External landmark
Introitus.

Question 4

Repère interne?

Answer 4

vessie

Question 5

Anatomie pertinente?

Answer 5

Relevant anatomy
Bladder, uterus, endometrial stripe, vagina, rectum, recto-uterine space, vesico-uterine space.

Question 6

Zone d’intérêt?

Answer 6

utérus, ligne endométriale

Question 7

Structure à identifier?

Answer 7

For transvaginal scanning, CPoCUS-IP must be able to:
Recognize and accurately outline uterine tissue.

Find and demonstrate the bladder on every scan.

Identify a gestational sac (if visible).

Identify a yolk sac (if visible).

Identify a fetal pole (if visible).

Identify a fetal heart within a fetal pole (if visible).

Accurately determine if a visible fetal heart rate is greater or less than 100 beats per minutes, using either the eyeball method (i.e. counting) or with M-mode (this is a more advanced technique and is not required for certification).

Accurately measure myometrial mantle (if required) by comparing it to the centimeter marks on the ultrasound screen or using calipers.

Recognize that in the sagittal plane, the endometrial stripe, when visible, should be located centrally along the long axis of the uterus, and the bladder appears near field on screen left.

Recognize that in the coronal plane, the endometrial stripe, when visible, should be more or less circular and located centrally within the uterus, and that the bladder appears across the entire near field of the screen.

Recognize that the vesico-uterine space is between the uterus and the bladder (i.e. anterior to the uterus) and that the recto-uterine space is between the uterus and the rectum (i.e. posterior to the uterus). Free pelvic fluid can appear in both locations.

A clean and disinfected endocavitary probe must be used for all new scans. Ultrasound gel should be placed on the probe head, then the probe should be covered with an approved sterile probe cover and sterile MUKO or lubricating jelly should be applied to the outside of the probe cover.

After the scan is complete the probe should be handled and cleaned as per local hospital policy (see System Care section for more details).

Question 8

Technique sagittale?

Answer 8

Sagittal approach:
Insert the probe into vagina with the beam directed towards the patient’s head and the probe marker oriented towards the ceiling. Direct the probe in a slightly posterior direction from the introitus.

Move the probe handle down to direct the beam anteriorly to identify the bladder.

Bring the probe handle up a few degrees to direct the beam posteriorly and then sweep from left to right to identify the uterus.

If the uterus is not seen, repeat step (3) as needed until the uterus is identified.

If the uterus was identified using the abdominal approach, the approximate location and orientation of the uterus should be known. This will allow an estimate of how much the probe handle needs to be moved up to find the uterus. The more retroverted the uterus, the more the probe handle will need to be lifted upwards to direct the beam posteriorly.

Once the uterus is identified, it should be centered on the screen and swept slowly from left to right until it disappears in both directions, looking for:
ALL criteria of an intrauterine pregnancy OR an endometrial stripe located centrally along the long axis of the uterus.
AND
Pelvic free fluid located anterior and posterior to the uterus (i.e. the vesico-uterine and the recto-uterine spaces).

Question 9

Technique coronale?

Answer 9

Coronal approach:
Upon completion of the sagittal scan, the probe should be rotated 90 degrees counterclockwise until the indicator is oriented towards patient right.

Move the probe handle down to identify the bladder.

Slowly sweep the probe posteriorly until the uterus is identified.

Center the uterus on the screen by moving the probe from left to right, as the uterus is often not fixed in the midline.

Once the uterus is identified and centered, it should be swept slowly from anterior to posterior until it disappears in both directions, looking for:
ALL criteria of an intrauterine pregnancy OR an endometrial stripe located centrally within the uterus.
AND
Pelvic free fluid located anterior or posterior to the uterus (i.e. the vesico-uterine and the recto-uterine spaces).

Question 10

Trucs si utérus pas visible?

Answer 10

If entire uterus is not visible:
1. Insert the probe slightly further into the vagina to ensure it is placed against the uterus.

2. In the coronal view: move the probe off centre.
3. In the sagittal view: ensure that sweeping is fully performed to the left and right to find a uterus that is not in the midline.
4. In both coronal and sagittal views: continue to bring the probe handle up as needed to find a retroverted uterus.
5. Move to transvaginal scanning.

Question 11

Trucs si utérus et sac gestationnel sont visibles, mais pas l’oeuf?

Answer 11

If uterus with gestational sac is visible but yolk sac is not visible:
1. Change view from sagittal to coronal or vice versa. The yolk sac is shaped like a flat disk. This maneuver may allow the yolk sac to be seen in cross section, yielding a much clearer image than when the beam is at right angles to the sac.

2. Increase probe frequency.

Question 12

Pièges interprétation des images?

Answer 12

Mistaking a pseudo-gestational sac for an intrauterine pregnancy.
Failure to ensure bladder-uterine juxtaposition. A pregnancy is only considered to be safe if the surrounding tissue is confirmed to be uterine using bladder-uterine juxtaposition and continuity with the vagina (in the longitudinal view using the abdominal approach).
Mistaking maternal blood flow in the decidual reaction as fetal cardiac activity.

Question 13

Pièges génération d’image?

Answer 13

Sweeping too quickly.
Not using the abdominal approach first.
Not inserting the probe far enough into the vagina to make contact with the uterus and getting a poor view or no view of the uterus.
Inadequate sweeping (i.e. not sweeping until the uterus disappears).
Not moving far enough from side to side, or posteriorly enough (probe handle up) to find the uterus.

Question 14

Pièges de l’intégration clinique?

Answer 14

Assuming that a scan that does not have ALL criteria for a safe intrauterine pregnancy (i.e. not strictly applying the 3-2-1 rule) cannot be an ectopic pregnancy.

Assuming that free fluid in the pelvis is physiologic. Even though physiologic free pelvic fluid is quite common, its presence is not always benign. Scans should always be repeated; the upper quadrants should be interrogated and elective imaging in radiology should be performed based on the clinical context of the patient. Any free pelvic fluid should be considered acute blood until proven otherwise if it is suspected to be increasing in volume, if it fills both the recto-uterine and vesico-uterine spaces (i.e. the fluid surrounds the uterus) or if it is also present in the upper quadrants.

Mistaking physiologic fluid for blood. A small amount of fluid in the pelvis can be normal, provided that it is not increasing in size or extends into the upper quadrants.

Declaring a safe IUP when no yolk sac is visible and a presumed fetal pole does not have an obvious fetal heart. This structure could just be debris within the uterus.

Question 15

Autres pièges?

Answer 15

Always bring the probe handle down to identify the bladder.

Always outline the margins of the uterus when scanning, both for proctored certification scans and in clinical practice. The uterus can be difficult to recognize when compared to other tissues and the margins of the uterus are where free fluid will appear.

Utilize zoom function. May be useful when the gestational sac is quite far field and decreasing depth would take the uterus off the screen.

Use M-mode (if comfortable with this skill) to measure fetal heart rate if unable to accurately determine with the eyeball method (i.e. counting)

Question 16

Technique avancée G en T1?

Answer 16

Advanced Technique Consideration in First Trimester Pregnancy
(not required for CPoCUS CORE IP Certification):

For accurate dating of a pregnancy, ultrasound measurement of the fetal crown-rump length (CRL) in the first trimester (≤13 6/7 weeks of gestation) is the most precise method to confirm gestational age (GA), with an accuracy of ±5-7 days. The measurement used for GA dating must be the mean of 3 discrete CRL measurements and be obtained in a true sagittal plane. The genital tubercle and the fetal spine must be aligned and the maximum length from cranium to caudal rump measured as a straight line.
Note: Mean sac diameter (MSD) measurements are not recommended for deriving the estimated due date (EDD). Using CRL to derive the EDD does not apply to pregnancies resulting from assisted reproductive technology (ART).

Question 17

critèere confirmer une grossesse?

Answer 17

Pregnancy:
To declare an intrauterine pregnancy, a CPoCUS-IP must apply the “3-2-1” rule to ALL First TM scans:
Pregnancy criteria (3) – need ALL three criteria to confirm a pregnancy:
Decidual reaction.
Gestational sac.
Yolk sac or fetal pole with visible fetal heart. The presumed fetal heart must be well away from the very vascular decidual reaction to avoid false positives.

Question 18

Critères GIU?

Answer 18

Pregnancy criteria (3) – need ALL three criteria to confirm a pregnancy:
Decidual reaction.
Gestational sac.
Yolk sac or fetal pole with visible fetal heart. The presumed fetal heart must be well away from the very vascular decidual reaction to avoid false positives.
Intrauterine criteria (2) – need ALL criteria above plus the following two criteria to confirm the pregnancy is in the uterus:
Bladder-uterine juxtaposition. At least one image must clearly show the bladder and uterine tissue in direct contact.
Vaginal-uterine continuity. In the longitudinal view, the vagina must be shown to transition directly into uterine tissue.

Question 19

Critères de sécurité?

Answer 19

Safety criteria (1) – need ALL criteria above plus the following criteria to confirm that an intrauterine pregnancy is in a safe location within the uterus:
1. Adequate myometrial mantle. The shortest distance between the inner edge of the gestational sac and the outer edge of the uterus must be at least 8 mm. This distance can be estimated by comparing it to the centimeter markers on the ultrasound screen. In equivocal cases, the distance should be precisely measured using the electronic calipers.

To declare a live intrauterine pregnancy, a CPoCUS-IP must confirm ALL criteria above plus:

Visible fetal heart rate greater than 100 beats per minute. The presumed fetal heart must be well away from the very vascular decidual reaction to avoid false positives. The fetal heart rate can be counted or measured with M-mode, depending on the experience of the clinician.

Any scan that does not clearly have ALL criteria for an intrauterine pregnancy MUST be declared No Definite IntraUterine Pregnancy (NDIUP). This assumes the patient has an ectopic pregnancy until proven otherwise and helps avoid false positive First TM scans.

Question 20

scan nég pour liquide libre?

Answer 20

Negative scan for pelvic free fluid: Adequate visualization and complete sweep of the vesico-uterine and the recto-uterine spaces, in both the sagittal and coronal planes, without evidence of free pelvic fluid.

Question 21

scan positif pour liquide libre?

Answer 21

Positive for pelvic free fluid: Sagittal or coronal view of free pelvic fluid in the vesico-uterine or the recto-uterine space.