D) Delayed phaseD) Delayed phase
CT – we will not do delayed phase unless haemangioma suspected.
Please specify “? haemangioma” on request form.
Haemangioma SummaryHaemangioma Summary
Common- often incidentalCommon- often incidental
US – Echogenic -no halo. No colour flow.US – Echogenic -no halo. No colour flow.
Aytpical – hypo-echoic in fatty liverAytpical – hypo-echoic in fatty liver
- mixed echotexture- mixed echotexture
CT – C- low densityCT – C- low density
C+ peripheral vessels (uneven)C+ peripheral vessels (uneven)
C+ PV /delay progressive fill-inC+ PV /delay progressive fill-in
Small haemangioma fill in immediately andSmall haemangioma fill in immediately and
cannot be distinguished from metastates.cannot be distinguished from metastates.
MRI features similar to CT post GadoliniumMRI features similar to CT post Gadolinium
Arterial enhancementArterial enhancement
(central and early)(central and early)
Washout on portal venousWashout on portal venous
indicates fast flowindicates fast flow
HCC SummaryHCC Summary
US - usually heterogeneous Usually HepB +ve withUS - usually heterogeneous Usually HepB +ve with
raised alpha FPraised alpha FP
CT – C- low densityCT – C- low density
C+A – central early contrast (high flow rate)C+A – central early contrast (high flow rate)
C+PV – washout cf with liverC+PV – washout cf with liver
–– may have a capsulemay have a capsule
MR – intracellular fat on T1 out of phaseMR – intracellular fat on T1 out of phase
- similar perfusion characteristics to CT- similar perfusion characteristics to CT
MRI IMAGES of LIVERMRI IMAGES of LIVER
Look at CSF first to tell if T1 or T2Look at CSF first to tell if T1 or T2
T1 are grey. Fluid is dark. Black outlineT1 are grey. Fluid is dark. Black outline
T2-incl HASTE.T2-incl HASTE.
More definition. Fluid is bright.More definition. Fluid is bright.
Gadolinium – always with T1Gadolinium – always with T1
Fatty liver with sparingFatty liver with sparing
Same pt - out of phase T1 MRISame pt - out of phase T1 MRI
Same patient - CT non-contrastSame patient - CT non-contrast
CT COLONOGRAPHYCT COLONOGRAPHY
(for fun only)
Axial to loops
Advantages / disadvantagesAdvantages / disadvantages
Sensitivity and specificity is of the order of 90 %Sensitivity and specificity is of the order of 90 %
for 10 mm polyps.for 10 mm polyps.
Easy, quick and well tolerated.Easy, quick and well tolerated.
Beats barium enema hands down.Beats barium enema hands down.
Safer than optical colonoscopySafer than optical colonoscopy
Approx. half the price of optical colonoscopyApprox. half the price of optical colonoscopy
No intervention possible as in optical CyNo intervention possible as in optical Cy
At present for “Ba enema” indications, but is likelyAt present for “Ba enema” indications, but is likely
to be used for screening in future.to be used for screening in future.
Radiology manpower training required.Radiology manpower training required.
Radiation dose equivalent to Ba EnemaRadiation dose equivalent to Ba Enema
Incidence of Colonic Perforation at CT Colonography: Review of
Existing Data and Implications for Screening Asymptomatic Adult
Source: InternationalWorking Group on Virtual Colonoscopy
Total VC studies considered 21,923
Symptomatic Perforation Rates for VC* 0.005%
Total Perforation Rates for VC 0.009%
Perforation Rates for Conventional Colonoscopy 0.1-0.2%
CTC vs Optical ColonoscopyCTC vs Optical Colonoscopy
CTC for average risk and Fam Hx pts.CTC for average risk and Fam Hx pts.
> 50 yrs (radiation)> 50 yrs (radiation)
Contraindicated if inflammatory bowel or on steroidsContraindicated if inflammatory bowel or on steroids
(risk of perforation as inflation is done “blind” as(risk of perforation as inflation is done “blind” as
opposed to Ba enema).opposed to Ba enema).
Optical Colonoscopy – if biopsy or polypectomy probOptical Colonoscopy – if biopsy or polypectomy prob
All polyposis syndromesAll polyposis syndromes
High riskHigh risk
Inflammatory Bowel DiseaseInflammatory Bowel Disease
Consider “Is intervention likely to be needed?” – (cf MRCP vs ERCP)
Complex Folds at flexuresComplex Folds at flexures
Barium enema 6 – 8 mSvBarium enema 6 – 8 mSv
CTC estimate of 7.6 mSv with low mAs.CTC estimate of 7.6 mSv with low mAs.
Increased noise, but high resolutionIncreased noise, but high resolution
improves definition of small polypsimproves definition of small polyps
Thin slice, limit tube currentThin slice, limit tube current
Background radiation is 2.4 MSv/yearBackground radiation is 2.4 MSv/year
The worldwide average background dose for a human being is about 2.4 milli
sievert (mSv) per year. This exposure is mostly from cosmic radiation and
natural isotopes in the Earth. This is far greater than human-caused background
radiation exposure, which in the year 2000 amounted to an average of about
0.01 mSv per year from historical nuclear weapons testing, nuclear power
accidents and nuclear industry operation combined, and is greater than the
average exposure from medical tests, which ranges from 0.04 to 1 mSv per
year. Source Wikipedia.
Small Bowel ImagingSmall Bowel Imaging
< 35 yrs – MRI for radiation reasons< 35 yrs – MRI for radiation reasons
However if pre-surgical workup–fluoroscopyHowever if pre-surgical workup–fluoroscopy
CT Enteroclysis – only difference from CT isCT Enteroclysis – only difference from CT is
negative contrast in bowel. No advantage tonegative contrast in bowel. No advantage to
do if recent normal CT.do if recent normal CT.
MR Small bowel – breath-hold sequences,MR Small bowel – breath-hold sequences,
dynamic change between sequences. Gooddynamic change between sequences. Good
soft tissue differentiation. +/- Gadoliniumsoft tissue differentiation. +/- Gadolinium
Normal Fluoroscopic EnteroclysisNormal Fluoroscopic Enteroclysis
Low density barium
Pumped in to distend
Intubation 10 min
Study 20 min
CT EnteroclysisCT Enteroclysis
Tumor shows up against negative contrast in bowel. Positive contrast could hide it
CT ENTEROCLYSISCT ENTEROCLYSIS
Volumen oral contrast for 45 min pre scanVolumen oral contrast for 45 min pre scan
IV MaxolonIV Maxolon
IV contrast on tableIV contrast on table
CT to include anal canal and with sagittal.CT to include anal canal and with sagittal.
CT ENTEROCLYSISCT ENTEROCLYSIS
Jejunum often thick-walled
Can evaluate bowel wall due to
negative contrast in lumen and
IV contrast in wall.
Evaluates stomach well also
Plus standard CT
Reserved for older patients due
to radiation dose
MRI Small BowelMRI Small Bowel
Oral Volumen 30 – 45 min prior (or Ioscan)Oral Volumen 30 – 45 min prior (or Ioscan)
+/- IM Buscopan for peristaltic movement+/- IM Buscopan for peristaltic movement
Good for Crohns patients with multiple studiesGood for Crohns patients with multiple studies
and large radiation dose over time.and large radiation dose over time.
Coronal TRUFICoronal TRUFI
Coronal TRUFI fat saturationCoronal TRUFI fat saturation
Coronal HASTECoronal HASTE
Axial HASTEAxial HASTE
Coronal T1Coronal T1