justification of the use of ct for individual health …...dept. of radiology tongji hospital,...

Dept. of Radiology

Tongji Hospital, Huazhong University

of Science & Technology,

Wuhan, CHINA

Liang Wang, MD, PhD

Professor, attending radiologist

[email protected]

Justification of the use of CT for

individual health assessment of

asymptomatic people: the Chinese

experience

Knowing asymptomatic is important:

a condition that it fails to show noticeable

symptoms

may develop symptoms later and require watch

and wait or early treatment, e.g. cancer

may resolve itself or become benign

Be alert to possible problems

unknowingly spread the infection to others

Precautionary steps must be taken

Background

Excerpt from Wikipedia

Certain CT procedures for IHA of asymptomatic

people are justified in certain circumstances in

some countries

The proportion of CT exams as source of radiation

is increasing

Technologic advance is profoundly changing our

understanding of the use of CT for IHA of

asymptomatic people

Background

Objectives

to summarize and analyze the utilization of CT for

IHA of asymptomatic people in China

Keypoints:

Feasibility and necessity of CT for IHA of asymptomatic

people in China

Rational use of CT for IHA of asymptomatic people in

China

Current application status of CT for IHA of asymptomatic

people in China

Chinese data:

Usage of CT has increased dramatically over the

last two decades in Chinese hospitals

More than10,000 CT scanners in Chinese

hospitals

Rural community hospitals may have one or more

CT scanners

CT scanners per million Chinese population is 8.6

1.Feasibility and necessity of CT for IHA of

asymptomatic people in China

State-of-the-art imaging modalities in one Top

10 Hospital in China

Tongji University Hospital

Chinese data:

a hospital’s medical statistics

2010:

Out-patients: 2.90 million

In-patients: 86,000

Operations: 42, 000


people are justified inChina

The price of a CT exam is cheap in China, e.g.15-

32 € per plain CT head exam

Among medical diagnostic modalities, CT

contributes the most man-made radiation in China

Technology advances are profoundly reducing CT

dose, e.g. coronary CT angiography

Feasibility and necessity of CT for IHA of


Chest :Coronary CT angiography (CTA)

Patients with myocardial infarction or sudden

cardiac death may be asymptomatic in China

CTA is used as an IHA tool for detecting

coronary artery disease of asymptomatic people

in China, e.g. low dose CTA was used to

evaluate coronary stenosis, and characteristics

of a plaque, especially vulnerable plaque, in

asymptomatic people

2.Rational use of CT for IHA of


Chest : Coronal CTA

Li, et al published a CTA IHA study in 584

asymptomatic people to assess the prevalence

of noncalcified coronary plaques

38.4% had non-calcified plaques

Conclusions: Hypercholesterolemia and diabetes

mellitus are high risk factors for the prevalence of

noncalcified plaques for asymptomatic people

Rational use of CT for IHA of


Academic Radiology, Vol 19, No 5, May

2012

Chest: Coronal CTA

Dual source CT (DSCT) with adaptive sequence is

currently considered to be the most effective tool to

reduce radiation dose of CTA in China

Xu, et al, published a DSCT IHA study to evaluate

coronary artery stenosis in early diabetes or

prediabetes asymptomatic myocardial ischemia.

Diabetes Care 2013;36(6):1687-94



Chest: Coronal CTA

Lv, et al. demonstrated volume CT dose index

(CTDIvol) produced by prospective ECG gating CTA

was about a quarter of the value with retrospective

ECG gating CTA in their study



Indications for Coronal CTA as an IHA tool for




men

elderly over the age of 40

family history of premature

coronary heart disease,

smoking (current smoking

> 10 cigarettes / day)

high blood pressure

high cholesterol

severe obesity

(overweight> 30%)

history of cerebral

vascular or peripheral

vascular occlusion

Chest :lung

Most IHAs focus on the detection of early-stage

lung cancer and lung damage of asymptomatic

smokes with CT in China



Chest :lung

Wang, et al.published a low dose CT IHA study in the

population > 40 years old.In 500 cases, there were 6

cases of lung cancer

tube voltage 120-140kV

tube current 10-30mA for 50 kg body weight, 20-30mA for

60 kg body weight, 30mA for > 80 kg body weight

image quality could meet diagnostic requirements,

radiation dose has decreased by 75-90%



Chest :lung

Li, et al. published an IHA study of low-dose lung

HRCT (tube voltage 120kV, tube current 40 mAs)

to investigate the lung damage of asymptomatic

smokers and non-smokers

found that the incidence of lung emphysema, air

trapping and pulmonary parenchyma

micronodule were significantly increased in

smokers than non-smokers



Chinese guidelines on lung cancer IHA with low

dose CT

Age of 40 years or above

high-risk groups:

smokers and passive smokers,

family history of cancer

occupational dust or radiation exposure history

regular contact with cooking oil fumes (COF)



Head

Head CT is used as an IHA tool for

detecting intracranial lesions, skull

lesions and other head diseases of




Head

Wang, et al published a head CT IHA study of 21,358

asymptomatic people

demonstrated asymptomatic cerebral infarction (ACI)

prevalence was 3.84%, followed by sinusitis,

encephalomalacia, intracranial tumors and skull bone

tumors

ACI is low before the age of 40

ACI rise after the age of 40 years old



Head

Ding, et al, published a head study with low dose

CTA (tube voltage 80kV, tube current 150 mAs) to

investigate intracranial aneurysms (ICA)

Effective radiation dose was reduced by 69.73%

no significant differences in sensitivity, specificity and

accuracy for the detection of ICAs

Rational use of CT for IHA of asymptomatic

people in China

Indications for low-dose head CT as a IHA tool

for asymptomatic people in China



40-49 years old with

high blood pressure

Diabetes

Smoking

Alcoholism

family history of stroke and

intracranial arterial

stenosis

over 50 years old

routine annual low-dose

CT IHA for head

diseases

less than 40 years old

not recommended for

routine CT to avoid

ionizing radiation

Head: Nasopharynx

Globally, 80% of patients with nasopharyngeal

carcinoma (NPC) are in China

Early NPCs are mostly asymptomatic but can

be detected by IHA with CT



Head: Nasopharynx

Chen, et al, published a study with low dose

skull base CT ( a decrease in tube current

from 200 mAs to 70 mAs)

ocular radiation was reduced (from

145.38mGy to 50.34 mGy)

image quality is not significantly sacrificed



Indications for low-dose CT as a NPC IHA tool

for asymptomatic people in China



Liver in the southern provinces of China

Aged 30 to 59 years

Family history of NPC

regular contact with cooking oil fumes (COF),

carcinogenic chemicals

Tobacco and alcohol use

Abdomen and pelvis

Early neoplasms of abdomen and pelvic, such as

HCCs, are mostly asymptomatic but can be

detected by IHA with CT

High tube current is usually used in routine

abdominal and pelvic CT to obtain high image

quality, which leads to a high radiation dose to the

patient

Simply reducing tube current leads to an increase in

image noise


people in China

Abdomen and pelvis：liver

Xu, et al, used iDOSE enhanced CT iterative

reconstruction technique to obtain high-quality

images at lower dose levels

effective dose (ED) was reduced by 49.71%


people in China

Indications for low-dose liver CT as an IHA

tool for asymptomatic people in China

HCC Risk Factors & High Risk Populations



Hepatitis B

Infection

Hepatitis C

Infection

Alcohol

Aflatoxin B1

Drugs, medications, chemicals,

such as vinyl chloride

Hemochromatosis

Cirrhosis

Abdomen and pelvis：Pancrease

Hu, et al, published a pancrease study with

low dose GE lightspeed VCT (abdominal

circumference/current: < 90cm/60-80mA; 90-

110cm/70-90mA; 110cm/90-100mA)

to obtain high-quality imaging at lower

radiation dose



Abdomen and pelvis：kidney

Mu, et al, published a RCC IHA with CT (tube

voltage 120kV, tube current 100 mAs)

obtained satisfactory perfusion images

effective radiation dose was 8.95mSv



Indications for low-dose kidney CT as an IHA

tool for asymptomatic people in China

RCC Risk Factors & High Risk Populations



Over 40 years old

Smoking

Obesity

At other professional such

as oil, leather, asbestos,

other industries

Family history of RCC

Abdomen and pelvis：kidney

Zhu, et al, published a urinary calculi study

with low dose CT (tube voltage 120kV, tube

current 50 mAs)

obtained high quality images to detect urinary

stone



Abdomen and pelvis：Bladder

Chen, et al, published a study with low dose

bladder CT (tube voltage 120kV, tube current

40 mAs) after inflating bladder

obtained satisfactory images to detect urinary

lesions



Indications for low-dose CT as bladder cancer

IHA tool for asymptomatic people in China

Bladder Cancer Risk Factors & High Risk

Populations:



family history of bladder cancer

smokers

contact with carcinogenic chemicals

Abdomen and pelvis：Colorectum

Chen, et al, published a colorectal cancer

IHA study with low dose CT (tube current 50

mAs) after inflating colorectum

obtained satisfactory images

sensitivity, specificity, and accuracy were

96.5%, 62.5%, 89.2%, respectively



Indications for low-dose CT as a colorectal

cancer IHA for asymptomatic people in China



positive

immunoassay fecal

occult blood test

first-degree relatives

with colorectal

cancer

history of cancer

history of intestinal

polyps

have both or more of the following:

chronic diarrhea

chronic constipation

bloody stool

mucus containing stool

psychiatric injury

history of chronic appendicitis

Bone

Feng, et al, published a lumbar disc

herniation (LDH）IHA with CT in

asymptomatic air force fighter jet pilots

LDH accounted for 27%



Bone

Zheng, et al, used iterative reconstruction

technique in 256-slice lumbar spine CT to

obtain high-quality imaging at lower radiation

dose



3.Current application status of CT for IHA

of asymptomatic people in China


people are justified inChina

CT for IHA of asymptomatic people is being

performed in China

CT examinations for IHA of asymptomatic people

mainly reimbursed by employers in China

Multidisciplinary research efforts is profoundly

changing our understanding of the use of CT for IHA

of asymptomatic people in China

THANK YOU

Liang Wang, 王良,MD, PhD

full professor, attending radiologist

[email protected]

justification of the use of ct for individual health …...dept. of radiology tongji hospital,...

Documents