Radiology Flashcards
psoas muscle
radiographic marker of retroperitoneum. If they aren’t seen on radiograph, it may be that they are obscured by pathology.
3-6-9 rule
Parameters of normal bowel size. Small bowel diameter < 3 cm Large bowel diameter < 6 cm Cecal diameter < 9cm
Markers of bowel distension on xray
- small bowel contains valvulae conniventes - folds. When you see the lines across the lumen indicate small bowel dilation - large bowel dilations may be surgical emergency. Haustra are lines of large bowel - do not cross entire lumen.
why get pt to sit upright or an xray (supine x ray)
Reveals air-fluid levels that are a result of sluggish movement in the bowel, allowing time for fluid to level out and air to rise. - more than 3 air-fluid levels is abnormal.
pneumoperitoneum
air in intra-peritoneal space - suggests perforation of an intraperitoneal portion of GIT; What organs would be repsonsible?
retroperitoneum
air in retro-peritoneal space - suggests perforation of an retroperitoneal portion of GIT What organs would be responsible?
C-HAND
For rectal bleeding. Check pneumonic. Colitis Hemorrhoids Angiodysplasia Neoplasm Diverticulosis
Good modalities for imaging bones
radiographs and CT because they’re high contrast
Good modalities for imaging uterus
Ultrasound and MRI good definition of soft tissues
Good modalities for imaging prostate
Ultrasound and MRI good definition of soft tissues
Good modalities for imaging bladder
Ultrasound and CT ultrasound = good definition of soft tissue CT = high contrast ; useful when there is a concern for caliculi
What modalities to use first for adults of reproductive age?
Ultrasound and MRI (have less ionizing radiation) Radio graphs and CT had more ionizing radiation.
Orienting an ultrasound image
point of cone is the top (where the probe is on the skin) and base of cone is the bottom. in an abdominal US, you would see skin at top, followed by bladder, then uterus.
Endovaginal exam
- ultrasound - allows us to get closer to uterus because we don’t have to go through bladder.
Ultrasound in pregnancy: when they can be done
- Can see a pregnancy on ultrasound as early as 5 weeks - at 11 weeks dating ultrasound; may get a transvaginal exam for better detail - 20 weeks detailed anatomical scan
Visualizing follicles in ovaries
Can see them in MRI. Ultrasound can see cysts.
Visualizing prostate gland
transabdominal or transrectal ultrasound. Transrectal exam can take biopsy at the same time. Transrectal exam is therefore only done when pt needs a biopsy. The size of the prostate gland has nothing to do with cancer. Benign prostatic hyperplasia is normal, but may interfere with urination. Not well seen on CT.
Ionizing radiation in which modalities
X Ray & CT (MRI and ultrasound do not)
In CT how do we describe density?
We use the word attenuation to describe density differences in the scan. Higher positive score = more dense.
Describe C2
Has the dens process that sticks up to articulate with the base of the skull. Remember to count two at the top of the cervical spine to account for this.
Describe C1
It is a little ring that sits on C2 called the anterior arch.
Special view for evaluating C1 and C2
Open mouth view
CRT
Cardiothoracic ration used clinically to assess enlarged heart or excess fluid in pericardial space. mediastinum wides/thoracic cavity width
Atypical cervical vertebrae
C1 and C2, don’t have typical components and behave differently in trauma situations
Recognize dense of C2 nestled in C1
