Gastrointestinal Tract Flashcards
List concentrations on volume of barium used for the various barium studies :
Name 2 GIT agents that inhibit intestinal mobility to improve diagnostic accuracy in GI studies
Buscopan (Hyoscine -N-Butylbromide)
Antimuscarinic - also inhibits gastric secretion
20 mg IV repeated at 15 min intervals up to 40 mg in an hour
Immediate onset. Duration 5-10 min
Glucagon - smooth muscle relaxation
0.2 - 0.5 mg IV over 1 min. (1 mg IM) - Ba meal
0.5 - 0.75 mg IV over 1 min (1-2 mg IM) - Ba enema
1 mg IM - CT or MR small bowel > 1 mg N/V possible. 1 min to onset (relatively long), Duration 15-20 min
What are the contrast amounts for angiograms of the celiac axis, SMA and IMA ?
Buscopan to get rid of subtraction artifact
Celiac axis - Supine - 25-36 ml contrast at 5 to 6 ml/s
SMA - 25-42 ml at 5-7 ml/s
IMA - 10-20 ml at 4 ml/s
Catheters : selective femorovisceral, sidewinder, cobra
What pulse sequences are used for MR of the GIT?
Axial and coronal and sagittal in first instance.
Minimize movement artifact - breath-hold gradient echo and single-shot fast-SE sequences - poor contrast resolution
Baseline - Fast-SE T1 and T2 with GAD and FS as necessary- occasionally suffer from movement artifact
What radiopharmaceuticals and dose is used for a gastrointestinal-esophageal reflux radionuclide study
99m Tc-colloid or 99 m Tc-DTPA with:
Adults and older children: 150-300 ml OJ with equal volume 0.1 M HCl - NPO 4-6 hrs
Infants and young children: milk - studied at normal feed
Adult dose : 10-20 MBq- 40 MBq (0.9 mSv ED)
- liquid with tracer is given and washed down with liquid. Semirecumbent
What radiopharmaceuticals are used in what meals in a gastric emptying study
1 Liquid meal - Max 12 MBq 99 TC-tin colloid (0.3 mSv ED) with 200 ml OJ or milk or formula for infants
- Solid meal - Scrambled wgg same as above dose or 99Tv-DTPA. Other bread and milk to add up
- Combined dual isotope
- liquid dose as 1 with 200 ml OJ
- solid 2 MBq 111 In (Indium) 0.7 mSv labelled-resin beads mixed into pancake 27g fat 18g protein 625 cals. Plus other bulk.
What pharmaceuticals and what dose is used for a Radionuclide Meckel’s diverticulum scan
99 m Tc pertechnetate (IV) 200 MBq (2.5 mSv ED), 400 MBq max (5 mSv ED).
Injected dose localizes in ectopic gastric mucosa within the diverticulum
Posterior and lateral images
What radiopharmaceuticals wnd dose are used in radionuclide imaging of GI bleeding ?
99 m TC labelled RBCs 400 MBq max (4 mSv ED)
What is the radio-pharmaceuticals and dose used for radionuclide imaging of the liver and spleen ?
99 m Tc tin or sulphuric colloid 80 MBq (ED 1 mSv)
200 MBq for SPECT
Cleared by phagocytes into RES
What radiopharmaceuticals are used and dose needed for radionuclide scan of GB and hepatobiliary tree
99 m Tc TBIDA (high hepatic uptake and low urinary excretion - better visualization of biliary tract)
or IDA derivative 80
MBq (1 mSv ED)
150 MBq max (2 mSv ED)
99m Tc pertecnetate 10 MBq (0.13 mSv ED) to show stomach
What drug and dose is given to children for excretion of radio pharmaceutical used in hepatoobiliary imaging ?
5 mg/kg/ day phenobarbital orally divide into 2 for 3-5 dys prior study to enhance excretion of radiopharmaceutical
Technique for Barium swallow
Technique for barium meal
Technique for ascending urethrography - male
Preliminary - coned supine PA bladder base and urethra
- Supine
- Foley flushed with 50 ml contrast to eliminate air bubbles
- Aseptic - catheter to fossa navicularis - balloon inflated to 2-3 ml water to anchor catheter and occlude meatus
- Contrast injected and steep 30 to 45 degree oblique films are taken
- Gentle traction on catheter to straighten penis over ipsilateral leg to prevent urethral overlap or foreshortening from obscuring pathology
If can relax bladder neck can fill bladder to avoid going up in VB for descending micturating if indicated
Technique for retrograde pyeloureterography
Technique for conduitogram - for anastomosis of ureter and ileal conduit
- Bring spare stoma bag or have patient bring from before
Technique for percutaneous renal cyst puncture and biopsy
- For biopsy, needle is deployed following confirmation of position with imaging
Technique for percutaneous antegrade pyelography and nephrostomy - introduction of drainage catheter into collecting system of kidney
To identify collecting system:
- Freehand or with biopsy needle attachment- US guidance to localize kidney and guide initial puncture into collecting system
- Excretion urography if adequate residual function and modulated system using parallax technique
- Occasional retrograde injection through an ileal conduit or ureteric catheter may be used to show the target collecting system
- Parallax. This method involves taking of two radiographs and the use of the principle of horizontal or vertical parallax. This method was first introduced by Clark (1909). The horizontal parallax involves taking of two radiographs at different horizontal angles and with the same vertical angulation - pocketdentistry.com
Antegrade pyelography rarely done alone. Done usually after nephrostomy. Oblique and AP X-rays taken with intro of water soluble contrast
Semierect films to ensure contrast down ureters.
Post nephrostomy best after 1-2 days
Technique for percutaneous nephrolithotomy - removal of calculi through a nephrostomy track - large can’t go through ECSWL
Then Dilatation:
GA - Teflon dilators from 7 to 30 F , introduced over guide wire. Or metal coaxial dilators or angioplasty balloon (10 cm long) are used.
Sheath is inserted over largest dilator or balloon through which scope is passed then removal or disintegrate calcs
Removal/disintegration:
< 1 cm calc - nephroscope and forceps. Larger disintegrated by ultrasonic or electrohydraulic disintegrator
Technique for renal areteriography
Technique for static renal radionuclide scanning with dose and pharmaceutical used
99m TC DMSA 80 MBq max (0.7 mSv ED) - uptake by renal cortex of up to 40-65%
Technique:
- Agent administered IV
- images acquired by gamma camera at 1-6 hr later
- no image in first hr due to agent in urine
Technique for dynamic renal radionuclide scanning with dose and pharmaceutical used
TC MAG-3 100 MBq (1 mSv ED) max
and
DPTA 150 MBq typical (5 mSv ED)
Technique:
- Supine
- IV radiopharmaceutical- image simultaneous
Technique and agent for Direct radionuclide micturating cystography - most frequently performed in children
99m Tc pertechnetate 25 MBq max (0.3 mSv ED) administered into the bladder
Technique:
- similar to MCUG - enables continuous imaging and a lower dose investigation
Technique for small bowel follow through
Technique for small bowel enema - largely superseded by MRI
Technique for barium enema
3 contd - barium administration should be paused. Gentle puffs of air for barium to flow to cecum
Rolls on to the right then onto the back
Barium in distal colon is run back out by lowering the infusion bag to floor or tilting table erect
- Catheter tube is occluded and air is gently pumped into the bowel to produce a double contrast effect. CO2 reduces incidence of severe pain post enema
Technique for instant enema - - water soluble contrast - identify level of LBO and degree of narrowing , extent and severity of mucosal lesions in active UC - urograffin 150 water soluble
Technique for reduction of an intussusception - air and fluroscopy
Preliminary - plain abdominal film - right side up decubitus confirms DX - failure of caecal filling
- Cont’d - 2nd enema often successful at complete reduction / resolution of the edematous ileocaecal valve
- If air or barium dissects between the 2 layers of intussusception - dissection sign - reduction is less likely
Technique for ultrasound reduction of intussusception vs barium
Technique for contrast enema in neonatal low intestinal obstruction
Urografin 150
Technique for sinogram
Technique for retrograde ileogram
Technique for colostomy enema and loopogram
Technique for herniogram
Technique for evacuating proctogram
Technique for endoluminal examination of the oesophagus and stomach
Technique - TA ultrasound of lower oesophagus and stomach
Technique for endoluminal examination of the rectum
Technique for CT colonography
30 ml gastrograffin 2hr before scan in a cleansed colon for for fecal tagging
50 ml evening before scan
OR
- low residue diet 2 days before, light breakfast and lunch day before then fast
- 100 ml gastrograffin of 150 ml omnipaque in 3 doses day before
MRI sequences used for suspected perianal fistula
Technique for radionuclide gastric emptying study
