Pelvis Lab
Case 1
36 year old woman with pelvic
pain
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What type of images are these (CT, MRI or plain films)?
What plane are they in (axial, sagittal or coronal)?
What type of imaging sequence is this, T1 or T2?
Hint, look at the fluid in the bladder is it bright or dark.
Remember that fluid is bright on T2 weighted sequences
On the this image, there are 3 soft tissue structures in the
pelvis, two you should be able to identify and one you
shouldn’t. What are the 2 normal structures you see in this
female patient?
Uterus
Bladder
???????
• What imaging plane is this? Axial
• What imaging sequence is this, T1 or T2? Hint, look at
the subcutaneous fat, is it bright or dark (fluid is also
dark, not shown)? What other things are bright on T1
weighted images. This is a T1 weighted sequence
Fat, blood and MRI contrast are bright on T1 weighted
sequences
• Now for the diagnosis in this case. Do you see
another structure that is high signal on these T1
weighted images? Look in the left side of the
pelvis. (click for arrow ) We then used an MRI
trick to help us figure out what was causing this
structure to be bright on T1 weighted images.
• What is the difference between these 2 images?
Hint, look at the fat.
We use a fat suppression technique, all of the fat is dark, even the fat in the
bone marrow. This helps us determine the cause of the high signal structure
in the left ovary. So what do you think is causing this lesion to stay bright on
this fat suppressed T1 weighted sequence????
• Since this high signal did not get dark with fatsuppression then it must be getting its high signal
from blood products as we didn’t give contrast.
This is an endometrioma, an area of endometrial
tissue, similar to the lining of the uterus but not in
the uterus (ectopic in location). This can be a
cause of pelvic pain in female patients.
Case 2
• What type of image is this?
• Can you point to the different bones and joints that make up
the bony pelvis (ilium, pubic rami and sacrum, SI joints and
pubic symphysis).
• Is there anything that looks “funny” about any of these
joints?
• Hint look at the pubic symphysis and the SI joints
• What do you think could have caused this (trauma,
congenital defect or infectious disorder)? Click for
answer
• For extra credit: do you see any fractures of the bones
of the pelvis? If you see this you, have a bright career
in radiology (click for answer).
Case 3
• What time of images are these? (Plain Films, CT
or MRI). CT
• What type of window is this set for (soft tissue or
bone)? Soft tissue window
This is a bone window, note how you can see the
bone detail between the cortex and marrow space.
• Is this a male or a female patient? Look at the
structures behind the bladder. Does this look like
a uterus or could these be seminal vesicles?
These are seminal vesicles
• What is the structure just posterior to the seminal
vesicles? Hint, it has air in it.
Rectum
• What are the small round structures just anterior to
the iliopsoas muscles? Hint, they are tubular,
bilateral, symmetric and on every image.
External iliac
artery and vein
• Take a look at the bladder, what is the round
low attenuation area (dark area) in it?
Foley catheter
• You see contrast in 2 places in these images, in
the bladder and anterior to the bladder. What is
the name anatomic space anterior to the bladder?
Prevesicle space
• This is a bladder rupture in a trauma patient. There
are 2 types of bladder ruptures, intraperitoneal and
extraperitoneal. For extra credit, what type is this?
Hint, is the prevesicle space intra or extraperitoneal?
This is an extraperitoneal bladder rupture. For an
intraperitoneal bladder rupture you would see
contrast between the bowel loops.
There is a big difference in treatment between the
two types of rupture. Intraperitoneal ruptures are
treated surgically where extraperitoneal ruptures are
treated conservatively.