EMERGENCY CT – IS IT BEING OVERUSED?!!!

PROF.C.AMARNATH, MD, FRCR, PHD,

PROF & HEAD , DEPT OF RADIODIAGNOSIS,STANLEY MEDICAL COLLEGE, CHENNAI – 1

CONSULTANT RADIOLOGIST,SCANS WORLD, CHENNAI

Is CT scan overused?

Overuse has been defined as any procedure or test which is undergone to a patient for an inappropriate indication.

Definitely, the answer is “yes”.

Virtually anyone who presents in the emergency room with abdomen pain or a headache or syncope or minor head injury will automatically get a CT scan.

The rate of CT use grew 11 times faster than the rate of ED visits during the last 10 year period.

Just 3.2 percent of emergency patients received CT scans in 1996, while 13.9 percent of emergency patients seen in 2007 received them.

This means that by 2007, 1 in 7 ED patients got a CT scan. It also means that about 25 percent of all the CT scans done in the United States are performed in the ED.

Less than 7.1 percent of patients presenting to the emergency department with dizziness and 6.4 percent complaining of syncope or near-syncope benefited from head CT

Why overused?

Several factors contribute to the increased use of CT scans: The greater availability of the equipment; Doctors’ fear of being sued for malpractice; A perception that patients want the test;

and Financial pressure to make use of the

machine

CT is “user-friendly” for the clinician, the patient and the radiologist.

It is readily available, very fast, produces high-quality images, and is capable of detecting a wide array of illnesses

CT scanners are commonly housed in or near the ED itself, and there is no barriers to get the CT done.

At the same time, the relatively high-radiation doses associated with CT have also raised health concerns

EMERGENCY CT

Trauma headache vertigo, dizziness or light-headedness abdominal pain convulsions impairments of nerve, spinal cord or brain

function flank pain general weakness

PAN SCAN (WHOLE BODY CTSCAN)

Pan scan should be used only on certain prescribed indications.

But nowadays it is used even in minor injuries as well as in stable patients.

Whole-body computed tomography in polytrauma: techniques and management. Linsenmaier U et al Eur Radiol. 2002 Jul; 12 (7): 1728-40. Epub 2001 Dec 13

HOW TO REDUCE OVERUSAGE?

Many of these recommendations are being promoted through the “Choosing Wisely initiative”, a campaign developed by the ABIM Foundation that has collected and communicated guidelines from across the medical community.

to help physicians and patients engage in informed conversations about unnecessary tests, treatments and procedures.

Choosing Wisely Campaign guidelines

Three specific guidelines (initial). American College of Emergency Physicians (ACEP),

states that doctors should “avoid CT scans of the head in emergency department patients with minor head injury who are at low risk based on validated decision rules.”

For syncope: “Avoid CT of the head in asymptomatic adult patients in the emergency department with syncope, insignificant trauma and a normal neurological evaluation

The another guideline on headache: patients who come to the emergency room with a headache but no other complications or risk factors should not get CT scans.

Some other recent recommendations Don’t do imaging for low back pain

within the first six weeks, unless red flags are present. ( severe or progressive neurological deficits or when serious underlying conditions such as osteomyelitis are suspected).

Don’t start with CT for children suspected of appendicitis. (USG –PRIMARY)

Neuroimaging (CT, MRI) is not necessary in a child with simple febrile seizure.

Avoid Unnecessary CT

The Canadian CT Head Rule (CCHR), a clinical

decision rule designed to safely reduce imaging in minor head injury by

differentiating mild

traumatic brain injury

from clinically important

brain injuryOne in every three CT scans performed on patients with minor head injury is unnecessary

Indications for CT C-spine in ER

The Canadian C-spine Rules and NEXUS rules -an x-ray or CT as the their first line imaging modality.

Clearly CT is much more accurate than x-ray at detecting significant injuries( a moderate-high suspicion for a fracture or dislocation).

3 factors… The patient’s “protoplasm” – Do they have a history of

osteoporosis? Are they very elderly? Do they have a history of ankylosing spondylitis?

The likelihood of obtaining a high quality x-ray image – Is the patient bull-necked? Do they have severe osteoarthritis?

The mechanism of injury and physical exam – Was it a high risk mechanism of injury such as ejection from a car? Are they altered making the physical exam unreliable? Are there any focal neurological signs?

Avoid Unnecessary CT

Facet dislocation

Cervical spine fracture dislocation

Burst fracture

Involvement of middle and posterior columns Presence of retropulsed bone fragments Integrity of above and below vertebrae

TRAUMATIC PSEUDOANEURYSM

Post traumatic vascular occlusion

Diagnostic work

up

Acute Abdomen

Ultrasound Abdominal plain film

CT MRI

Which is the best choice?

Diagnostic work

up

Acute Abdomen

US

US CT CT

CT CT

Acute Abdomen

MRI

Pregnancy Young

patientswhen US inconclusive

Cholecystitis

Gallstone Wall thickening Intraluminal sludge Sonographic

Murphy’s sign +++

Gynecologic emergency

Salpingitis

Ovary cyst

Ovary torsion

Case RUQ

What does the US examination show?

1) Acute cholecystitis

2) Free fluid in the Morrison pouch

3) Increased echogenicity of the intraperitoneal fat in RUQ

CaseRUQ

Which is the main CT

finding?

1) Ascending colon

diverticulitis

2) Omental inhomogeneity

3) Mesentery inhomogeneity

CT as the first line examination

CT is used as a first line modality in a number of emergency cases where we can’t rely on other modalities, or if there is a danger of missing diagnosis or if there is a fear of getting delayed for treatment.

When ? When the sensitivity of other modalities in acute abdomen is too low to diagnose conditions…

Why ? How ? What side effects ?

CT versus APF : APF is an insensitive modality

Sensitivity of APF Ahn Radiology 2002 871 patients

Bowel obstruction : 49 % Urolithiasis : 9 % Appendicitis, pyelonephritis, pancreatitis,

diverticulitis : 0 % Intraabdominal foreign body : 90 %

Sensitivity of APF Mackersy Radiology 2005 91 patients

30 % for APF versus 96 % for CT

APF for the diagnosis of pneumoperitoneum

Sen : 50 - 70 % Accuracy decreases

APF less and less analyzed (even if performed) Compromise Sen/Spe

170 p with suspicion of bowel perforation APF upright including diaphragmatic domes Sen = 78 % with Spe = 50 % Chen SC J Emerg Med 2002

ACUTE ABDOMEN Consider abdominal

ultrasound as the initial diagnostic test in suspected uncomplicated appendicitis, nephrolithiasis, or diverticulitis, gynecologic conditions and biliary conditions.

Acute appendicitis Diameter ≥ 6 mmPPV, NPV ≥ 95 %Kessler Radiology 2004

Acute appendicitis

Identification of the normal appendix - A weakness of US

A normal appendix would be identified in only 5 % of patients (NEJM jan 2003)!!!appendix is identified in 64 % of cases (Kessler Radiology 2003)

- A strength of CTCT identifies normal appendix in 80 % of cases (Benjaminof Radiology 2003)

CT or US in appendicitis

US CT first line

- thin patients - fat patients- young women - peritoneal

findings- recent clinical findings - diffuse pain- children - failure with

US

Colic pain

CT advantages : Sen Spe Alternatives

Dgs Easier Faster

37

High velocity accident Middle-aged female Hemodynamically unstable Glasgow Coma Score 3/15

Case 2

• Suggested method of examination

1. X-ray2. US3. CT4. DSA

38

CT revealed subarachnoidal bleeding, cervical spine fracture, normal chest

Abdominal CT was also performed

Case 2

39

Case No. 2.

• Any further remarkable findings?

– complex pelvic fracture

– right psoas muscle hematoma

– liver parenchymal tear

Case 2

40

Types of shock: hypovolemic cardiogenic distributive

Patient developed a hypovolemic shock due to a large hemorrhage

“Hypoperfusion complex” consists of diffuse dilatation of intestines with fluid intense enhancement of bowel wall increased enhancement of the adrenal glands diminished caliber of the abdominal vessels

(„flat cava” sign) decreased splenic enhancement

Case 2

41

Case No. 2. – A similar case

42

Abdominal injury – diagnostic algorithm

• (history, physical examination, lab tests)

• Plain X-ray– abdomen

• erect or decubitus• supine

– chest– bones

• lower ribs• spine• pelvis

• Ultrasound

• Computed tomography

MDCT

43

4 good reasons to perform CT:

plain abdominal X-ray / abdominal US may not be executable

plain abdominal X-ray / abdominal US may not be diagnostic

relevant information may be expected from CT only:(complete overview of the parenchymal organs, bowels, mesentery, omentum, peritoneum, retroperitoneum, vessels, bones, etc.)

time requirement of CT is much shorter

Abdominal injury – diagnostic algorithm

62 year-old female, acute onset of abdominal pain

What is your diagnosis?1) Acute mesenteric ischemia2) Crohn disease3) Infectious enteritis4) Portal vein thrombosis

Case

Acute mesenteric ischemia

Arterial contrast phase:Embolus in SMA

•Enhancement of prox. Jejunum

• No enhancement of remaining small bowel

• Clot or reduced lumen in SMA

• Segmental wall thickening

• Lack of mucosal enhancement

• No stranding

• Pneumatosis intestinalis

Bowel perforation : choice of surgical procedure

Ulcer perforation coelioscopy

Bowel perforation : choice of surgical procedure

Jejunal diverticulitis with perforation → laparotomy

Bowel perforation : choice of surgical procedure

Colic perforation with stercoral peritonitis → colostomy

Bowel obstruction : choice of surgical procedure

• When a surgical procedure is scheduled, CT has an impact +++

How ?

Multidetector CT : axial 1 mm thick slice for acquisition, 3mm for reading

2 questions Added value of reformatting

SBO Appendicitis Bowel perforation

Added value of iv contrast

Value of reformatting in BO

Same Sen and Spe

the diagnostic confidency

Paulson Radiology 2005

Value of reformatting in appendicitis

Same Sen and Spe

the diagnostic confidency

Paulson Radiology 2005

Subtle finding : the whirl finding

Patients with suspicion of BO in an oncologic population : 1213 patients

Small bowel volvulus at surgery : 11 patients (1%)

Sensitivity Specialized GI radiologist : 64 % Senior resident : 27 %

Gollub JCAT 2006

Midgut Volvulus

Midgut Volvulus

Whirl sign

Soft-tissue mass with an internal architecture of swirling strands of soft tisssue and fat attenuation

Best shown in the plane perpendicular to the axis of rotation

Non specialized physician will ask CT

Prevalence of disease decreases Suspicion of appendicitis

Surgeon : 70 % Emergency department physician : 40 %

Suspicion of colic pain urologist : 80 % Emergency department physician : 60 %

Predictive positive value decreases

OMGE(6 097 cases)

ARC(3 772 cases)

MODALITY

Appendicitis 24,1 % 26 % CT / USCholecystitis 8,9 % 10 % USGynecologic disease

6 % 7 % US

Obstruction 4 % 9 % CT SAP in FU

Colic pain 3,4 % 4 % CT or nothing

GI perforation 2,8 % 4 % CTPancreatitis 2,3 % 4 % CTDiverticulitis 2,1 % 2 % CTMesenteric ischemia

1 % 1 % CT

NSAP 43 % 22 % CT or nothing

Is the abdominal x-ray dead?There still remains several indications for the use of abdominal x-rays in emergency radiology.

1. Radio-opaque foreign body – metal, leaded glass or large objects such as packets found in drug mules

2. To look for free air in suspected perforated viscous in patient who is not stable enough to leave the ED for a CT

3. Known chronic diagnosis with multiple frequent recurrent acute exacerbations such as recurrent small bowel obstruction, especially in patients who have had multiple CT scans in the past

RADIATION HAZARD

There is no safe dose of radiation. Edward P Radford, MD

Scholar of the Risks from Radiation

Diagnostic Imaging Risk Procedures Effective Dose (mSv)

Risks

CXR (PA), extremity XR <0.1 Negligible

Abdomen XR, LS spine XR

0.5- 1 Extremely low “death from flying 7200 km”

Brain CT, single-phase abdomen CT, single-phase chest CT

1-10 Very low “death from driving 3200 km)

Multiphase CT 10-100 Low

Interventions, repeated CT

>100 Moderate

Comparative dose

DoseEquivalent

background radiation

Estimated deaths

Chest X-ray PA 0.1 mSv 3 d 1/1 million examinations

Abdomen X-ray 3 views 1.5 mSv 8 months 1/12,500

examinations

Standard-dose MDCT

10-15 mSv 100-150 times 7.2 y 1/1,250

examinations

Fo radults

Children who undergo CT scans in early childhood tend to be at greater risk for developing leukemia , primary brain tumors , and other malignancies later in life 

Justification

Main goal: reducing radiation dose (ALARA).

Only when properly indicated: is this examination of importance

(essential) for diagnosis and therapy in this patient?

Consider alternatives: Ultrasound: abdomen, neck, soft tissues,

chest MRI: small bowel, liver, brain

Conclusion CT ideally should be used as a diagnostic test rather

than a screening one because of its expense and unnecessary radiation exposure to the patient

CT scan overused –brain, Pulmonary angio

There are recommendations about when it is appropriate for physicians to order CT scans.- guidelines

CT may be considered as the first line imaging test in acute abdomen EXcept for suspicion of gynecologic conditions, biliary conditions, appendicitis in some cases, and except in children

Select the Right Imaging Exam-Radiation (ALARA ) Alternative diagnostic imaging

Thank youGood luck &

all the best !!!

Thank you for your

attention