Understanding the use and limits of CT , MRI and PET scans to evaluate cancer and screening

1. Cancer Imaging
ASPEC / January 2021 / Robert Miller MD

2. 1.History of imaging
technology
2.Guidelines for screening
or staging
3.Breast (mammograms,
ultrasound, MRI)
4.Lung (chest X-rays, CT,
PET scan)
5.Brain (CT, MRI)
6.Miscellaneous sites

3. History of Radiology

4. Wilhelm Conrad Röntgen
German] mechanical engineer and physicist
who, on 8 November 1895, produced and
detected electromagnetic radiation in
a wavelength range known as X-rays or
Röntgen rays.
About six weeks after his discovery, he took
a picture—a radiograph—using X-rays of
his wife Anna Bertha's hand
By 1896 doctors around the world were using x-rays to take pictures of patients

11. Radiology : use of radiation (X-rays and
high energy radiation) for diagnosis, and
now called Medical Imaging
Ultrasound – using focused high-frequency sound waves
X-rays – chest, mammograms, bone films
CT Scan (computed tomography) – slices of x-ray images combined by computer
MRI (magnetic resonance imaging) – strong magnetic field that aligns the protons of hydrogen atoms and
spins the protons to produce a faint signal that is detected
Nuclear Medicine – injecting an isotope into the patient and getting images to show where the radiation
concentrates
Bone Scan – use an isotope that concentrates in the bone
PET Scan (positron emission tomography) – use a positron releasing isotope attached to a specific agent
that will concentrate in the target (glucose for cancer or infection or high blood flow 18F-FDG or for bone
NaF-F18)
No radiation exposure using ultrasound or MRI
US Food and Drug Administration (FDA) estimates that
exposure to 10 mSv from an imaging test would be expected
to increase the risk of death from cancer by about
1 chance in 2000

14. www.xrayrisk.com/

15. Risk of radiation induced cancer is related to the patient age
and the type of procedure (dose of radiation they are exposed
to)

16. Only include mammograms for breast cancer screening, Low dose CT scans
for lung cancer screening, and option of CT for colon/rectal cancer screening
NCCN.Org
Which stages or cancers need CT, MRI or PET
scans and the frequency

17. Breast
Cancer
Imaging

18. right lung
left lung
heart
Normal
right
breast
Cancer left
breast
aorta
Reconstructed
PET Scan of
locally
advanced left
breast cancer

19. Three techniques that
show a 2.7cm left
breast cancer
-Mammogram
-MRI
-PET Scan

20. Imaging for Advanced Breast
Cancer
Young woman with large, triple negative cancer in the
left breast
mammogram
ultrasound
PET scan
MRI scan

21. Ducts and glands are dense and look
white or grey on an X-ray and fat is
lower density and looks black on an X-
ray
So mammograms may miss cancer on
younger women or women with very
dense breasts, and they may do better
with an MRI or ultrasound.

22. Internal mammary
supraclavicular
axillary
Lymph Nodes
The tail of the
breast may extend
high into the
axilla
Lymph nodes
may not be
seen on a
mammogram
but may show
up on an MRI or
PET scan

24. BIRADS
What does the
mammogram
report mean by
BIRAD ?
Breast Imaging, Reporting &
Data System (BI-RADS)

25. Probability of Breast Cancer
by BIRADS
BI-RADS 3 1.0%
BI-RADS 4 18.6%
4A 6%
4B 15%
4C 53%
Am J Prev Med. 2013 Jan; 44(1): 15–22.

26. Mammography
sensitivity: overall 80%
age: < 40y 54 – 58%
> 65y 81 – 94%
High breast density is associated with 10 – 29% lower
sensitivity
Sensitivity of only 50% in women with dense breasts and 33%
in BRACA study
Breast cancer is accurately diagnosed through mammography in about 78 percent of all women tested, while
diagnostic accuracy rises to about 83 percent for women over 50. false positives, about 6-8%, estimated 17% of
breast cancers missed by mammography. The number may rise as high as 30% for women with dense breasts

27. How often will a mammogram miss finding a cancer in a
young woman?
42 – 46%
Never!

28. Biopsy = 9mm invasive ductal cancer
Mammogram in a woman with fatty,
low density breasts

29. Breast Density can make imaging very difficult, this woman had a palpable mass that was
very difficult to see because her diffuse breast density
mammogram CT Scan
MRI

30. Typical benign
calcifications in
mammogram of
82 yo woman

31. Mammograms may often show areas of
calcification, these may be malignant. In
ductal carcinoma in situ (DCIS), there is
normally no mass but just an area of
calcification

32. Micro-
calcifications
can be very
subtle
Biopsy of this
area showed
8mm DCIS

33. Biopsy = DCIS with focal micro-invasion

34. Larger area of
micro-
calcifications may
have invasive
cancer
Path = 2.9 cm area
of high grade DCIS
plus invasive
ductal cancer

35. Mammogram report = 7mm
spiculated lesion in the
upper, outer part of the breast
Pathology = 1cm, grade 1,
invasive ductal cancer with
all nodes clear
Mammogram of Early
Breast Cancer

36. Regular Mammogram with Compression Views to Better Show the
Lesion, biopsy showed 9mm Grade 1 invasive ductal cancer

37. Mammogram of
Advanced Breast
Cancer
Obvious tumor mass on
mammogram,
mastectomy revealed a
6 cm invasive ductal
cancer

38. Mammogram
80 yo woman with
nipple retraction
and mastectomy
performed
Path multi centric
lobular with +
deep surgical
margins

40. Ultrasound view of breast tumor
Needle biopsy using ultrasound
needle

41. Breast MRI
Path = 2.2 cm
cancer in right
breast, left breast
was benign
(False positive?)
benign

42. Breast MRI
Will show the breast tumor as well
as the lymph nodes
Mastectomy = 6cm lobular
cancer with 41 out of 42 lymph
nodes positive for cancer spread

43. Breast
MRI
Will show
the breast
tumor as
well as the
lymph
nodes

44. Breast MRI

45. MRI found unexpected
cancer in the right
breast (pink circle)
when only the cancer
on the left (yellow
circle) was suspected

46. Breast MRI Scan
A = Breast
B = axilla
C = internal
mammary nodes

47. Breast MRI Scan
In a woman with dense breasts, the mammogram was
normal but the MRI showed the cancer

48. mammogram
Breast MRI
MRI may show deep tumors that can be missed on the edge of
the mammogram images and can be better seen and the depth
on the MRI

49. Sometimes the Breast MRI Can Show Too Much
Information

50. MRI Advanced Left Breast Cancer with Lymph Node Spread
normal
breast
cancer
satellite
nodules
lymph
node
mets

51. MRI Advanced Left Breast Cancer with Lymph Node Spread
Side view
cancer
lymph
node
mets

52. MRI Advanced Left Breast Cancer
with Skin Thickening (same patient)

53. CT Scan Anatomy

54. cancer
Normal Left
Breast
Heart
Left
lung
Right lung
Advanced cancer of the right breast on CT

55. Locally Advanced Left Breast Cancer
implant cancer
implant

56. Internal Mammary Node Relapse
IM node
aorta
esophagus
trachea
SVC

57. PET - CT Scan Anatomy

58. PET Scan Anatomy for Breast Cancer

59. PET Scan Anatomy for Breast Cancer

60. PET Scan Anatomy for Breast Cancer

61. Normal breast
Liver
Heart
Spine
Rt Lung
Lt Lung
Cancer in Lt breast
Cancer in Spine
PET Scan Anatomy for Advanced Breast Cancer

62. 3D Mammography More Likely to Find Small Invasive
Breast Cancers, Especially in Women Younger Than 50
Three-dimensional mammography (also called digital breast tomosynthesis, digital tomosynthesis, or just
tomosynthesis) creates a three-dimensional picture of the breast using X-rays.
the study found that screening with 3D mammography increased breast cancer detection rates by about
40%.
•73.7% of breast cancers found with 3D mammography were 1 centimeter (cm) or smaller and node-
negative
•65.4% of breast cancers found with digital mammography were 1 cm or smaller and node-negative
•This difference in detecting small breast cancers was especially notable in women age 40 to 49. For these
women, 3D mammography found 4.41 invasive cancers per 1,000 exams in women with nondense breasts
compared to 2.71 invasive cancers per 1,000 exams found by conventional 2D digital mammography.

63. 3D Mammogram versus Conventional 2D
2D 3D
2D

64. Lung Cancer Imaging

65. Chest X-ray….where’s the cancer?

66. Chest X-ray….where’s the cancer?
heart
aorta
nodes
cancer

67. CT Tells All

68. CT Better Than X-ray

69. Lung Anatomy and
Important Lymph Node
Regions

70. PET Showing Lymph Nodes Spread with Lung
Cancer
SupraClavicular Mediastinal Hilar
N3 N2 N1
Lung
Lung
Heart

71. On a CT scan, the cancer,
the fluid and the
collapsed lung may all
look the same (grey)
The PET will show the
difference since is shows
metabolism (how much
glucose is being
consumed in the area,
cancers consume a very
high quantity and appear
bright yellow)

72. SBRT with Tomotherapy
PET Scan before and 2 Months after Tomotherapy
PET Scan helps
to find the
cancer and also
helps to prove
whether the
radiation has
killed the cancer
(the grey scar
should no
longer be hot
on the PET)
Hot
Cold

73. Brain Imaging

74. Standard test is an MRI (not a
CT scan) given with
intravenous contrast
(gadolinium).
Since a brain biopsy may not
always be an option it is
critical that the radiologist
can accurately identify the
correct diagnosis

75. Better definition from an MRI than a CT
CT Scan = edema MRI = multiple mets

76. CT Scan MRI Scan
Better definition from an MRI than a CT

77. The tumor may
be almost
invisible on the
MRI unless IV
contrast is given

78. PET scans are not very
helpful for brain
tumors. Since the brain
uses large amounts of
glucose it looks so
bright on the PET a
tumor would be hard
to see.

79. Multiple Brain
Metastases
from Lung
Cancer

80. Everything in Not Cancer
Small Strokes Brain Abscess

81. Bone Imaging

82. MRI better
than simple
X-ray

83. MRI Much Better Detail than an X-ray

84. CT Image showing missing bone in vertebra

85. MRI side view of
cancer in a vertebra
and pressure on the
spinal cord and
nerves causing
symptoms

86. PET even more information than the MRI
MRI
PET

87. Conventional
bone scan
better than
plain X-rays
and more
modern bone
scans are even
better