1. Radiology Basics
David J. Eschelman, M.D., FSIR
Professor of Radiology,
Sidney Kimmel Medical College of Thomas Jefferson University
Co-Director of Interventional Radiology,
Thomas Jefferson University Hospital

2. So what is a radiologist?

3. So what is an
interventional radiologist?

4. Imaging Modalities
• CT (computed tomography)
• US (ultrasound)
• MRI
(magnetic resonance imaging)
• PET-CT
(positron emission tomography)

5. CT
• Pros:
– Available everywhere, consistent quality, best option
for whole-body evaluation
– Fast
• Cons:
– Less sensitive for small liver metastases than MRI
– Radiation (10-15 mSv)

6. Chest CT – Lung Metastases

7. Ultrasound
• Pros:
– Relatively inexpensive.
– No radiation.
– Can be very sensitive for small lesions
• Cons:
– Variable quality, depending on site and on patient.
– Not useful for whole-body surveillance.

8. Biopsy

9. MRI
• Pros:
– Most sensitive for liver mets.
– No radiation. No known harmful effects
• Cons:
– Does not cover entire body
– Can’t use in SOME people with pacers, anxiety, etc.
– Variability in how studies are done.
– Slow, noisy, easily affected by motion, etc.

12. 8/11/2010

13. 10/27/2010

14. 12/23/2010

15. 4/09/2010

16. MRI is better than CT (another example)
CT
MRI

17. MRI is better than CT (yet another example)
CT MRI

18. PET-CT

19. PET - CT
• Pros
– Unique: Images metabolic activity
– May give information about efficacy of treatment
• Cons
– Not universally available
– Expensive
– Not sensitive for small metastases
– Takes about 2 hours
– Radiation (30 mSv)

21. Surveillance Imaging
• Surveillance Scheduling
– No consensus: Varies from center to center
– Depends on tumor histology and genetics
• Jefferson protocol
– Low/intermediate risk: MRI q6-12 mo, CXR q12 mo
for 5 years
– High risk: MRI q3 mo + CT chest q 6 mo for 2 years,
then MRI q6 mo + CT q 12 mo for 3 years

22. NCCN Guidelines v1.2018
RISK OF DISTANT METASTASIS -
Low risk:
• Class 1A(x)
• Disomy 3
• Gain of chromosome 6p
• EIF1AX mutation
• T1 (AJCC) (See ST-1 and ST-2)
• Spindle cells
SYSTEMIC IMAGING BASED ON RISK STRATIFICATION
• Imaging to evaluate signs or symptoms as clinically indicated
• Consider surveillance imaging(y)

23. NCCN Guidelines v1.2018
RISK OF DISTANT METASTASIS -
Medium risk:
• Class 1B(x)
• SF3B1 mutation
• T2 and T3 (AJCC) (See ST-1 and ST-2)
• Mixed histology (spindle and epithelioid cells)
SYSTEMIC IMAGING BASED ON RISK STRATIFICATION
• Imaging to evaluate signs or symptoms as clinically indicated
• Consider surveillance imaging(y) every 6–12 months for
10 years, then as clinically indicated

24. NCCN Guidelines v1.2018
RISK OF DISTANT METASTASIS -
High risk:
• Class 2(x) • PRAME mutation
• Monosomy 3 • Epithelioid cells
• Gain of chromosome 8q • Extraocular extension
• BAP1 mutation • Ciliary body involvement
• T4 (AJCC) (See ST-1 and ST-2)
SYSTEMIC IMAGING BASED ON RISK STRATIFICATION
• Imaging to evaluate signs or symptoms as clinically indicated
• Consider surveillance imaging(y) every 3-6 months for 5 years,
then every 6-12 months for 10 years, then as clinically
indicated

25. NCCN Guidelines v1.2018
Surveillance:
The most frequent sites of metastasis are liver, lungs, skin/soft tissue,
and bones. At minimum, all patients should have contrast-enhanced MR
or ultrasound of the liver, with modality preference determined by
expertise at the treating institution. Additional imaging modalities may
include chest/abdominal/pelvic CT with contrast. However, screening
should limit radiation exposure whenever possible. Scans should be
performed with IV contrast unless contraindicated.
. . . . . but also add:
(y) Recognizing that there are limited options for systemic recurrence and
that regular imaging may cause patient anxiety, some patients may elect
to forgo surveillance imaging.

26. Background Radiation
Sources:
• Cosmic radiation
• Naturally occurring radioactive materials (radon, radium)
• Fallout
Exposure in US:
• Approximately 3 mSv/yr (low altitude)
• 30-50% higher in Denver
• Transatlantic flight – 0.08 mSv (2-3x higher over poles)
• 2x higher in US Capitol (8 hrs/day) – granite, marble

27. Radiation
Imaging Examples Effective Dose Range
(mSv)
Background Equivalent
Radiation Time
Radiation Risk Descriptora Probability of Cancer From
Imaging (%)
Probability of No Cancer
From Imaging (%)
CT scan or nuclear
medicine scan
1-10 Years Minor ∼0.05 ∼99.95
Abdominal radiograph 0.1-1 Months Minimal ∼0.005 ∼99.995
Chest radiograph or
mammogram
< 0.1-0.1 Days to weeks Negligible ∼0.0005 ∼99.9995
aDescriptors are from [78]
Dauer L et al. AJR 2011, 196

28. Brenner: DJ, Hall EJ: Computed Tomography — An Increasing Source of
Radiation Exposure. N Engl J Med 357:2277, November 29, 2007

29. Contrast Risks
• CT contrast and MR contrast are completely
unrelated materials
• Risk of reaction to CT contrast is very low
(0.15%)
• Risk of reaction to MR contrast is extremely low
(0.04%)
• Most reactions are minor

30. Contrast Reactions
Contrast and Renal Insufficiency
CT: “Contrast nephropathy”
MR: NSF

31. FDA Drug Safety Communication:
FDA warns that gadolinium-based
contrast agents (GBCAs) are
retained in the body; requires new
class warnings
May 22, 2017, updated December 19,2017

32. Gadolinium Contrast for MRI
• Per FDA:
Gadolinium retention has not been directly linked
to adverse health effects in patients with normal
kidney function, and we have concluded that the
benefit of all approved GBCAs continues to
outweigh any potential risks.
• Linear vs. macrocyclic
• Eovist is one of the lower linear “accumulators”
(lower dose administered, excreted by kidneys
and liver, more stable than other linear agents)

33. RECIST Criteria
Complete Response (CR)
Disappearance of liver lesions
Partial Response (PR)
> 30% decrease in the sum of the longest diameters
(“sum LD”) relative to baseline sum
Stable Disease (SD)
Absence of change which would qualify as
response or progression
Progression (PD)
> 20% increase in the sum LD in liver lesions OR
appearance of one or more new liver lesions

34. Initial Presentation
MRI was normal 6 months ago

35. Rapid Growth without Treatment
12/17/2013
4/30/2014 6/2/2014

36. Any Questions?