Body CT Modules: CT of the Ovaries and Uterus

1. Body CT Modules:CT of the Ovaries and Uterus Sean Stanley MS3 OHSU Fall 2006

2. CT of the Ovaries and Uterus Sources Siddall KA. Multidetector CT of the female pelvis. Radiol Clin North Am. 01-NOV-2005; 43(6): 1097-118 Casillas J, Joseph RC, Guerra JJ Jr. CT appearance of uterine leiomyomas. Radiographics. 1990 Nov;10(6):999-1007. Foshager MC, Walsh JW. CT anatomy of the female pelvis: a second look. Radiographics. 1994 Jan;14(1):51-64; Outwater EK, Siegelman ES, Hunt JL. Ovarian teratomas: tumor types and imaging characteristics. Radiographics. 2001 Mar-Apr;21(2):475-90. Pannu, HK, et al. MD CT Evaluation of Cervical Cancer: Spectrum of Disease. Radiographics 2001; 21:1155–1168 Rha SE, et al. CT and MR imaging features of adnexal torsion. Radiographics. 2002 Mar-Apr;22(2):283-94. Roberts JL, Dalen K, Bosanko CM, Jafir SZ. CT in abdominal and pelvic trauma. Radiographics. 1993 Jul;13(4):735-52. Roobolamini, SA. Imaging of Pregnancy-related Complications. Radiographics 1993; 13:753-770. Saksouk FA, Johnson SC. Recognition of the ovaries and ovarian origin of pelvic masses with CT. Radiographics. 2004 Oct;24 Suppl 1:S133-46. Sam JW, Jacobs JE, Birnbaum BA. Spectrum of CT findings in acute pyogenic pelvic inflammatory disease. Radiographics. 2002 Nov-Dec;22(6):1327-34. Yang DM. Retroperitoneal cystic masses: CT, clinical, and pathologic findings and literature review. Radiographics. 2004 Sep-Oct;24(5):1353-65. Buy, J-N, et al. Cystic Teratoma of the Ovary: CT Detection. Radiology 1989; 171:697-701

3. Purpose of this Presentation • Familiarize the student with looking at the amorphous world of CT-visualized pelvic anatomy. • Familiarize the student with CT-visualized pelvic anatomical changes over the female lifecourse. • Expose the student to a few common pathologies one might see on a pelvic CT. • Give student practice using “CT speak” and the “radiology approach”. **Caveats: it would probably be best to come to this presentation knowing a few basics about CT and about general anatomy. If you have never seen a CT or pelvic anatomy, check out some other basic resources first.

4. CT of the Ovaries and Uterus Table of Contents • Normal Anatomy • Anatomic Change Over the Lifecourse • Example Pathologies • Non-neoplasm • Neoplasms Discerning pelvic pathology from pelvic anatomy can be as hard as separating the weeds from the flowers in this field. Alpine Meadow, Mt Hood

5. CT of the Ovaries and Uterus Normal Anatomy Quick review of normal anatomy! • Ovary • Fallopian Tube • Uterus • Cervix • Vaginal Canal BUT THAT’S JUST A DRAWING!!

6. CT of the Ovaries and Uterus Normal Anatomy Quick review of normal anatomy! • Uterus • Fallopian Tube • Ovary • Cervix (out of plane) • Vaginal Canal (out of plane) Here’s the real thing! But unless you’re a surgeon, you’ll never see this.

7. CT of the Ovaries and Uterus Normal Anatomy • Ovaries • Fallopian Tubes • Uterus • Cervix • Vaginal Canal L R This is what you’ll see: a normal axial pelvic CT. Each image is a visual slice through the pelvis

8. CT of the Ovaries and Uterus Normal Anatomy • Ovaries • Fallopian Tubes • Uterus • Cervix • Vaginal Canal L R Which basically yields a radiographic visualization of pelvic anatomy.

9. CT of the Ovaries and Uterus Normal Anatomy • Ovaries: -paired organs -ovoid/almond shaped -normally up to 4cm in length -lie on either side of the uterus -variable size/density depending on what’s going on hormonally a) fluid density (like blood) b) soft-tissue density (like uterus) c) physiologic cysts (fluid with a border around it) -don’t enhance greatly with contrast L R These ovaries are relatively easy to see. Many times they are not so easy to see, as they can be displaced by the mobile abdominal contents or other masses. Look at lateral surfaces of uterus, up and down through planes to find them!

10. CT of the Ovaries and Uterus Normal Anatomy Hmmm. A bit harder to find? • Fallopian Tubes (oviducts): -normally difficult to visualize on CT, unless pathology -project from lateral aspect of ovaries to uterine fundus -Soft-tissue density (usually similar to uterine tissue) -0.1 to 0.5cm in diameter at isthmus -1 cm in diameter at ampulla L R

11. CT of the Ovaries and Uterus Don’t confuse this with the uterus, it’s the bladder, note the density -> fluid density (urine). Normal Anatomy • Uterus: -pear-shaped -about the size of human fist (8x5x2.5cm) -soft tissue density (it’s mostly a big muscle - compare to pelvic muscle.) -triangular endometrial cavity within (fluid filled/density), viewed in only certain planes -varies in size/density depending on age/parity of woman L R

12. Are you starting to discern things? Flowers at Mt.Hood You must learn how to look before you can see.

13. CT of the Ovaries and Uterus The Approach During the “Lifecourse” and “Pathologies” parts of this presentation we will use a repetitive 3-slide approach to each CT image. • Slide a: Describe what you see (using CT terminology - “density”, “mass”, “heterogeneous”, and other words that lead to understanding without jumping to a diagnosis - CT is an aid to diagnosis, to be weighed alongside clinical and other lab data, not necessarily a diagnosis clincher.) • Slide b: Read an example description, and brainstorm possible diagnoses that could present radiographically like that given description. • Slide c: Find out the answer and read a bit about it!

14. CT of the Ovaries and Uterus The Approach A quick CT terminology reference: (CT is all about description - you can’t really tell what something is by one glance at a CT, but you can tell how it looks!) • Attenuation (density) • Fat Attenuation (“fat density” - same density as fat on CT) • Fluid attenuation (same density as fluid on CT - kind of nonspecific - better to say “blood attenuation”[a little denser than average fluid due to cellular contents] or “water attenuation”[a little less dense than average fluid due to lack of cellular or proteinaceous content]) • Soft-tissue attenuation (same density as muscle on CT) • Bone attenuation (same density as bone on CT) • Contents: Heterogeneous v. Homogenous • Wall: Thin-walled v. Thick-walled • Border: Well-circumscribed v. Indistinct Borders • Internal borders: Septated • External Contour: Smooth v. Lobulated (lobed) • Path: Tortuous (serpiginous) • Size: enlarged v. atrophied • Contrast: enhancing (lights up with contrast) v. non-enhancing (doesn’t) • Location • Absolute - “in the cervical canal” • Relative - “posterior to the left ovary”, “medial to the right sacral wing”

15. CT of the Ovaries and Uterus Normal Anatomic Change Over the Female Lifecourse • Because the ovaries and uterus are part of the reproductive system, their function changes as the individual matures and ages. • Functional changes are reflected in the anatomy as visualized by CT.

16. CT of the Ovaries and Uterus Normal Anatomic Change Over the Female Lifecourse Lifecourse - case 1a Describe what you see inside the outline. 4 year old This is where you should say, “I see a small soft-tissue density uterine tissue in the mid-pelvis, between a bladder filled with homogeneous fluid density…blah blah blah”

17. CT of the Ovaries and Uterus Normal Anatomic Change Over the Female Lifecourse Lifecourse - case 1b Sample Description: - “Narrow strip of soft-tissue attenuation uterine tissue, nestled between a normal fluid-attenuated bladder (‘b’), and a normal stool-filled rectum (‘r’). Oviducts and Ovaries are indistinguishable from soft-tissue density uterus.” 4 year old b r Why might the uterus look that way?

18. CT of the Ovaries and Uterus Normal Anatomic Change Over the Female Lifecourse Lifecourse - case 1c “Premenarchal Stage” -OVARIES: :: are 1/3 of adult size (therefore difficult to visualize) :: have less mature follicles, therefore are more dense - closer to soft-tissue than fluid :: if visualized, ovaries can have normal microcysts up to 0.9cm -UTERUS: :: small :: non-engorged, therefore enhances less with contrast 4 year old uterus

19. CT of the Ovaries and Uterus Normal Anatomic Change Over the Female Lifecourse 33 year old Lifecourse - case 2a Describe what you see. Again, here is where you should say, “I see a larger soft-tissue density uterine tissue in the mid-pelvis with some regions of hyperdensity…etc and so forth”

20. CT of the Ovaries and Uterus Normal Anatomic Change Over the Female Lifecourse 33 year old Lifecourse - case 2b Sample Description: - “Engorged, greater-than-soft-tissue-attenuation, contrast-enhancing uterine tissue, flanked by normal sized ovaries having some heterogeneities of fluid- or soft-tissue attenuation.” Why might the uterus and ovaries look that way?

21. CT of the Ovaries and Uterus Normal Anatomic Change Over the Female Lifecourse 33 year old Lifecourse - case 2c “Premenstrual/Menstrual Stage” -UTERUS: :: enlarges to more globular shape, due to endometrial proliferation :: becomes more vascular (note higher attenuation than pelvic muscle) -OVARIES: :: enlarge to a length of up to 7cm. :: still consist of normal ovarian tissue (just possibly more of it!)

22. CT of the Ovaries and Uterus Normal Anatomic Change Over the Female Lifecourse Lifecourse - case 3a • Describe what you see.

23. CT of the Ovaries and Uterus Normal Anatomic Change Over the Female Lifecourse Lifecourse - case 3b Sample Description: • “highly dilated uterine tissue of mildly contrast-enhancing soft-tissue density, containing at its center a cavity mainly of fluid-density attenuation, but containing some peripheral regions of heterogeneously enhancing soft-tissue attenuation and amorphous central foci of bone-attenuation.” Why might the uterus look that way?

24. CT of the Ovaries and Uterus Normal Anatomic Change Over the Female Lifecourse Lifecourse - case 3c “Parous/Pregnant” Stage: (it’s a baby!) -UTERUS: :: the uterine cavity enlarges and is filled with fetal material and amniotic fluid. :: placenta is visible at the rim of uterine endometrium, and has the attenuation somewhere in between soft tissue and fluid/blood (think about the purpose of the placenta!)

25. CT of the Ovaries and Uterus Normal Anatomic Change Over the Female Lifecourse Lifecourse - case 4a • Describe what you see. 27 year old

26. CT of the Ovaries and Uterus Normal Anatomic Change Over the Female Lifecourse Lifecourse - case 4b • Sample Description: • “enlarged, heterogeneous uterine tissue of soft-tissue attenuation without general contrast-enhancement, but with peripheral scattered regions of enhancement” 27 year old Why might the uterus look that way?

27. CT of the Ovaries and Uterus Here’s another post-partum uterus, note the small amount of free air Normal Anatomic Change Over the Female Lifecourse Lifecourse - case 4c “Post-partum stage” (She just had a baby!) -UTERUS: :: enlarged, avg size of 9x12x14cm. :: may still have engorged vessels. :: small amounts of intrauterine fluid or blood are normal in the first 24 hrs post-delivery :: small amounts of intrauterine air occurs in ~25% of post-partum women :: Uterine size returns to normal in 6-8 weeks after delivery 27 year old

28. CT of the Ovaries and Uterus Normal Anatomic Change Over the Female Lifecourse • Lifecourse - case 5a • Describe what you see. 66 year old

29. CT of the Ovaries and Uterus Normal Anatomic Change Over the Female Lifecourse Lifecourse - case 5b Sample Description: • “normal sized uterine tissue of soft-tissue attenuation with some small foci of contrast-enhancement, flanked by small, dense ovaries of soft-tissue attenuation, without significant fluid enhancement.” 66 year old Why might the uterus and ovaries look that way?

30. CT of the Ovaries and Uterus Normal Anatomic Change Over the Female Lifecourse Lifecourse - case 5c “Post-menopausal stage” -UTERUS: :: size decreases (due to uterine endometrium atrophy) :: loses its cyclic engorgement -OVARIES: :: small :: featureless (the follicles are no longer under hormone stimulation) :: uniformly soft-tissue density 66 year old

31. Pathologies Continue to next presentation: CT of the Ovaries and Uterus- Part 2 Pathology