**Michigan Elderly DiCom Presentation**

# Washington, DC

## March 2007

Slide 1: Title slide

Medical Imaging Studies Provide Insight Into Aging and Why Elderly
Bodies May Tolerate Injurious Forces Differently, presented by Stewart
Wang, MD, PhD, University of Michigan for the CIREN Public Meeting in
Washington, DC, March 2007

Slide 2: Definition of the acronym DiCom and explanation of how it was
developed; image of a skeleton.

Slide 3: Discussion of the limitations (minor) and advantages (huge) of
using DiCom in both clinical and research settings.

Slide 4: Graph showing the increase in numbers and percentages of the
elderly beginning in 2000 with projections to 2050.

Slide 5: Graph showing the relationship between age and severe injury
separated by body region in frontal crashes for young and old drivers.
The numbers in parenthesis to right of the curve labels in the legend
are odds ratios which describe the size of the age effect. For
reference, an odds ratio of 1 would mean no age effect and increasing
odd ratios represent larger age effects.

Slide 6: Discussion of the changes that occur in human bodies with aging
and how this impacts what injuries can do to the elderly body. Leads to
the statement that we need to improve ATDs and models, better predict
injury patterns, and prioritize policy decisions.

Slide 7: Images of vertical rib cages for both young and elderly
patients that show the difference between rib angles for the two groups.

Slide 8: Images of horizontal rib cages again showing the differences in
the rib angles. Also illustrate that young ribs have more joint rotation
and less bone strain while the older ribs have less joint rotation and
more bone strain. (Kent 2005, Stapp Conference)

Slide 9: Discussion from above article (Kent 2005) asking if a few
degrees on the rib angles actually matters.

-   Angle change with aging offsets the effects of material changes and
    cortical thinning

-   Cortical thinning and decreased bone modulus can decrease the
    stiffness of the thorax, while rib angle increases stiffness

-   Creates decreased chest deflection tolerance for rib fractures

-   Older person's thorax does not deform more in response to force,
    however tolerable sternal deflection is much less

Slide 10: Discussion of prior studies and the current larger group of
participants.

-   First study included 111 CIREN and 50 non-CIREN patients

-   New study has 700 adults including a population of 300 CIREN
    patients.

-   Study participants are broken into two age groups (16-40 and 50+).

-   Attempting to confirm and extend earlier observations.

Slide 11: Discussion of the control populations for the study

-   Non-trauma CTs biased toward middle-aged and elderly populations;
    often have co-existing disease

-   Younger adults receive CTs due to related trauma

-   CIREN patient CTs contain significant injuries often leaving few
    uninjured segments to study

Slide 12: Graphs showing the age distribution of the control group v.
the CIREN group.

Slide 13: Graphs showing the weight distribution of the control group v.
the CIREN group.

Slide 14: Graphs showing the height distribution of the control group v.
the CIREN group.

Slide 15: Graph showing there is no significant height difference as
compared with age in the two groups.

Slide 16: Graph showing that CIREN subjects are significantly heavier
than the control group.

Slide 17: Graph stating that CIREN subjects have a significantly higher
BMI (body mass index) than those in the control group.

Slide 18: Graph showing that older ribs are more horizontal than younger
ribs in both CIREN and control groups at the right #9 rib angle.

Slide 19: Graphs showing that older ribs are more horizontal than
younger ribs when the groups are split into male and female groups at
the right #9 rib angle.

Slide 20: Graph showing that older ribs are more horizontal than younger
ribs in both CIREN and control groups at the right #10 rib angle.

Slide 21: Graphs showing that older ribs are more horizontal than
younger ribs when the groups are split into male and female groups at
the right #10 rib angle.

Slide 22: Image slide with four images from CT scans showing a thin
individual and one cut showing a patient with visible fat accumulation.

Slide 23: Graph showing that abdominal visceral fat increases with age
in both CIREN and non-CIREN patients. Also a CT cut showing a patient
with visible fat accumulation.

Slide 24: Three images:

-   A patient's body as it appears in a CT scan with no alterations

-   A patient's body with skin stripped away showing where the selected
    CT is made for the study

-   The actual two inch section taken for measurement purposes

Slide 25: Graph showing that abdominal subcutaneous fat increases with
age in both CIREN and non-CIREN patients. Also a CT cut showing a
patient with visible fat accumulation.

Slide 26: Image slide:

-   Screen shot from a crash test video

-   Screen shot from a computer model crash test video

-   CT image from a thin patient

-   CT image from a fat patient showing the difference between
    subcutaneous fat (SQ) and visceral fat

Slide 27: Graph slide -- effect of SQ fat on injury severity in frontal
crashes:

-   Shows a trend indicating that overall ISS decreases as subcutaneous
    fat increases

-   Shows a trend that Head MAIS decreases as subcutaneous fat increases

-   Shows a trend that lower extremity MAIS increases as subcutaneous
    fat increases

-   Shows a trend that abdominal MAIS decreases as subcutaneous fat
    increases

Slide 28: Graph showing that bone mineralization decreases with age in
both CIREN and non-CIREN patients. There is also an image showing L4
bone density.

Slide 29: Graph showing that chest bone volume changes with aging in
both groups of patients.

Slide 30: Graph showing that chest muscle volume changes with aging in
both groups of patients.

Slide 31: Literature review of the effect of soft tissues on chest
injury tolerance:

-   Verriest & Chapon (1985): soft tissues significantly affect overall
    resistance to applied forces

-   Yamada (1970): soft tissue deterioration begins between 30 and 40
    years of age

-   Zhou, Rouhana, & Melvin (1996): reduction of tolerance with aging is
    comparable to the reduction of soft tissue strength.

Slide 32: Graphs showing that males have more muscle volume than
females, but that both sexes show a decrease in muscle volume with age.

Slide 33: Graph showing that chest fat increases with age in both CIREN
and non-CIREN populations. The CIREN subset of patients is significantly
fatter than the non-CIREN subset.

Slide 34: Graph showing the relationship between age and severe injury
separated by body region in frontal crashes for young and old drivers.
The numbers in parenthesis to right of the curve labels in the legend
are odds ratios which describe the size of the age effect. For
reference, an odds ratio of 1 would mean no age effect and increasing
odd ratios represent larger age effects.

Slide 35: Title slide: Pelvis Geometry also Changes with Aging

Slide 36: Graph showing the gender distribution of knee, thigh, and hip
injuries in UM CIREN frontal crashes (2002).

Slide 37: Image slide:

-   Xray of a broken right femur

-   Screen shot showing where the force hits the leg during a frontal
    crash

-   3-D CT recreation of a left acetabular fracture with hip dislocation

Slide 38: Image slide:

-   3-D CT recreation of a male pelvis

-   3-D CT recreation of a female pelvis

Slide 39: Graph showing the acetabular cup angles by gender. Female
pelvises have greater open and slope angles than male pelvises.

Slide 40: Graph showing acetabular cup dimensions by gender. While the
genders are roughly similar with regard to acetabular width, females
have greater acetabular depth than males. Male femoral heads are
significantly larger than female femoral heads.

Slide 41: Graphs showing that patients with a greater open angle and
acetabular cup depth are less likely to receive a fracture in a frontal
crash.

Slide 42: Graph slide -- hip socket orientation changes with aging, open
angles:

-   Shows that the old have larger open angles than the young

-   There is a gender effect as well in that women's angles increase
    more than men's angles

Slide 43: Graph slide -- hip socket orientation changes with aging,
slope angles

-   Shows that the old have larger slope angles than the young

-   There is a gender effect as well in that women's angles increase
    more than men's angles

Slide 44: Graph slide -- hip socket orientation changes with aging,
acetabular width: patients show an increase in acetabular width with
aging.

Slide 45: Graph slide -- hip socket orientation changes with aging,
acetabular depth: patients show an increase in acetabular depth with
aging.

Slide 46: Summary slide:

-   Many changes in body composition and geometry with aging

-   Age can be broken down into measurable component for R&D

-   Men and women age different

-   Michigan CIREN is skewed toward fatter individuals (is all CIREN?)

Slide 47: DiCom is Indispensible for CIREN, it provides

-   Objective injury detail

-   Valuable insight regarding mechanisms

-   Can inform the development of better ATDs

-   Insight into injury tolerance

Slide 48: Image slide: do injuries captured in models or cadaveric tests
resemble real life injuries? Twelve reconstructed CT images of lower
extremity injuries.

Slide 49: Discussion slide depicting why DiComs will be fundamental for
the development of finite element human body models.

-   DiComs provide more detailed and anatomically accurate data

-   FEM models will incorporate factors which affect injury tolerance,
    providing insight into how body geometry and composition affects
    injury tolerance

Slide 50: Model slide showing the model validation process, comparing
and contrasting what happens in a model and what happens in a real life
crash.

Slide 51: Future priorities

-   Collect and analyze data from crashes with uninjured occupants

-   Incorporation of body composition data into FEMs

-   Guide model development and validation

-   Begin use of 4D DiCom

Slide 52: Image slide showing an aorta and a heart, illustrating how
difficult it is to obtain material properties of living tissues.

Slide 53: Aorta images is repeated. Gated CTs can show us how the aorta
works within the body.

Slide 54: Acknowledgement slide