الله بسمالرحمن الرحيم

FAST SCAN

Dr. Muhammad Bin Zulfiqar PGR NEW RADIOLOGY DEPARTMENT SIMS/SHL

What does it Mean?

FASTFocused Abdominal (Assessment

with)Sonography in Trauma

Fast Application• Indications:– Acute blunt or penetrating torso trauma

(stable or unstable patient )– Trauma in pregnancy– Pediatric trauma– Subacute torso trauma(unexplained

hypotension)• Goal: To identify fluid in a location where

it does not normally belong and detect visceral injury.

FAST USG SCAN

• ANATOMY

• TECHNIQUE

• FAST DEMO

• FREE FLUID

• ABDOMINAL ORGAN INJURY

Where can I see FF?

• Free fluid usually appears anechoic by US (black )

• Accumulation in area of injury• Overflows into dependent areas (pouch of

Douglas, Morrison’s pouch) via rivers (paracolic gutters) and into thoracic cavity

FAST: Anatomy

7 Dependent Sites1. Right Supramesocolic

(Morison’s pouch)2. Left Supramesocolic

(Splenorenal recess)3. Right Pericolic gutter4. Right Inframesocolic5. Left Inframesocolic6. Left Pericolic gutter7. Pelvic cul-de-sac

FAST: Technical Considerations

Standard Views• The Right Upper Quadrant View (Also Known as the

Perihepatic, Morison Pouch, or Right Flank View)• The Left Upper Quadrant View (Also Known as the

Perisplenic or Left Flank View)• The Pelvic View (Also Known as the Retrovesical,

Rectrouterine, or Pouch of Douglas View)• The Pericardial View (Also Known as the Subcostal or

Subxiphoid View)• The Right and Left Pericolic Gutter Views

FAST: Technical Considerations

Extended Views

• The Pleural Space Views

• The Anterior Pleural Space View

• The Parasternal View

FAST: Technical Considerations

• Standard views (standard FAST ): 1- Subxiphoid/Subcostal: Pericardium 2- RUQ: Morrison’s Pouch 3-Pelvis: Pelvic Cul-de-sac (Douglas )

Transverse Longitudinal

4- LUQ: Splenorenal & perisplenic spaces

• Extended views (E-FAST) :For pleural effusion

Supine patient

1

42

3

FAST: Subxiphoid exam

• Normal Anatomy

• Liver at very top of screen

• Epicardial fat vs. effusion

– Thin layer anterior to RV

– Not present posterior to

LV

Sonographic Representation of Heart Chambers

FAST: Subxiphoid exam

FAST: RUQ exam• Probe placed– Perpendicular– Mid-coronal plane– Just superior to the

iliac crest

• Probe facing– Toward patient’s

head

Evaluating– Hepatorenal

interface– Possibility of fluid

in Morison’s pouch ( Right Supramesocolic space)

FAST: RUQ exam

• Normal Anatomy• In the supine

patient, the hepatorenal space (Morison’s Pouch) is the most dependent space

Morison’s

Pouch

FAST: Pelvis exam

• Pelvis: Longitudinal Axis– Normal Anatomy– In the erect patient, the pouch of

Douglas (Retrovesical space ) is the most dependent space

FAST: Pelvis exam• Pelvis: Longitudinally and Transvers Axis. • Probe placed

– Transversally than Longitudinally– Midline 2 cm superior to the symphysis

pubis– “aimed” caudally into the pelvis (prostate )

• Probe facing– Toward patient’s head and right side.

• Best with some urine in bladder(acoustic window)

• Evaluating– Bladder ,Uterus in female ,and Prostate

in male– The potential spaces are Pouch of

Douglas (Cul de sac ) in female and Retrovesical space in male

– ‘

FAST: Pelvis exam

FAST: LUQ Exam

• Normal Anatomy• More difficult to evaluate

than RUQ (do not have liver as acoustic window)

• Left kidney more superior than right

• Splenorenal Recess , Potential space between kidney and spleen

• Presplenic /subphrenic space between spleen and diaphragm ( most common space for fluid collection in LUQ)

FAST: LUQ Exam

• Probe placed– Perpendicular– Mid - coronal plane– Just superior to the iliac crest

• Probe facing– Towards patient’s head

• Evaluating– Spleno-renal interface– Possibility of fluid in

Splenorenal recess and presplenic /subphrenic space( most common space for fluid collection in LUQ)

FAST: LUQ Exam

• Probe placed– Perpendicular– Mid - coronal plane– Just superior to the iliac crest

• Probe facing– Towards patient’s head

• Evaluating– Spleno-renal interface– Possibility of fluid in

Splenorenal recess and presplenic /subphrenic space( most common space for fluid collection in LUQ)

FAST: LUQ Exam

Extended FAST (E-FAST)

RUQ, LUQ views:• Check above diaphragm for hemothorax– CXR < US in detection of hemothorax

– 50-175cc vs. 20cc or less• US does not replace CXR

Suprapubic view:– Check uterus for pregnancy

FAST Demo

FAST Focused Abdominal Sonography In Trauma

Reliability• accuracy 86 - 97 % • sensitivity 88 - 91.7 % • specificity 94.7 - 99 %

Can detect 70 ml fluid (by linear probe can detect as little as 10 ml or less)

How To Interpret FAST

–Positive: • Fluid in pericardium or any 1 of 4 abdominal

windows–Negative:• No fluid in any windows

– Indeterminate:• If any one of the 4 windows is inadequately

visualized

Scoring System of Fluid

• In lower volumes, fluid accumulates in the pelvis or near the site of injury.

• It is not until there are larger intraperitoneal fluid volumes (>500 mL) that fluid is detectable in the perihepatic and perisplenic spaces.

• Recent studies show that FAST scan can detect fluid ranges from approximately 250 mL to 620 ml.

Abrams BJ, Sukumvanich P, Seibel R, Moscati R, Joelle D. Ultrasound for the detection ofintraperitoneal fluid: Am J Emerg Med 1999;17(2):117–20.

Scoring System of Fluid• One point is assigned to each anatomic site in which free fluid is

detected during the FAST scan, with a score ranging from 0 to 8.

• Fluid of more than 2 mm in depth in the hepatorenal or the splenorenal space was given 2 points instead of 1.

• Floating loops of bowel were given 1 point.

• 96% of patients with scores 3 required exploratory laparotomy; however, 38% of patients with scores <3 still required surgery.

• 84% sensitive and 71% specific for quantifying hemoperitoneum greater or less than 1 L.

Huang and associates 1994

Modified Scoring System

• Revaluated scoring system measures the depth of fluid in the deepest pocket, and 1 point is added for fluid in each of the other areas (four areas maximum.)

• 85% of patients with a score[3 required a therapeutic laparotomy, whereas 15% of patients with a score of 2 required surgery.

McKenney et al

Does FAST Make a Difference In Trauma Management?• During primary or secondary survey

FAST

Positive NegativeIndeterminate

unstable stable

OR

CT

unstablestable

ORDPL

CTDPL

Serial exam Repeat US/ CT

Adapted from: Rozycki GS, et al. J Trauma, 1996

Pearls

• Lack of FF ≠ no injury– Not enough to see (?too early)– You missed it– Hard-to-see places

• FF may not be blood – Urine, lavage fluid, ascites, amniotic fluid, bowel contents, ruptured cyst

Advantages of FAST

Easy & Early to Diagnose in

Resuscitation/Emergency room

Rapid(1 – 2.5 min)

Repeatable

Non-invasive

Low cost.

Difficult to distinguish Type of fluid Site of bleeding , Solid organ injury

Cannot evaluate retroperitoneum Difficult in the obese patient ,

subcutaneous emphysema Examiner Dependent. Bowel gas interposition False –Negative : retroperitoneal &

Hollow viscus injury

Disadvantages of FAST

Pitfalls and limits

• -Pre existing fluid collection ( Ascites , dialysis )• -Pelvic fluid collection (female ) .• -Fluid filled bowel loops .• -Contained injury (hollow viscus, bowel wall

contusion, pancreatic trauma and renal pedicle injury)

• -Echogenic clot.

Pearls• The scan should be repeated during the secondary

survey and also if the patient demonstrates clinical deterioration, since free fluid may have accumulated in the intervening time .

• The quality of images obtained may also be a limiting factor with patient obesity , gas in the bowel leading to degradation in image quality , subcutaneous emphysema , non-mobile patient and penetrating injury.

Does FAST replace CT?• Unstable patient, (+) FAST OR• Stable patient, low force injury, (-) FAST consider observing patient.

CT is far more sensitive than FAST for detecting and characterizing abdominal injury in trauma. The gold standard for characterizing intraparenchymal injury.

“Death begins with a CT.” Never send an unstable patient to CT. FAST, however, can be performed during resuscitation.

FAST

Positive NegativeIndeterminate

unstable stable

OR CT

unstable stable

OR

DPL

CT

DPL

Serial exam Repeat US/ CT

FREE FLUID

Pericardial Fluid

Pericardial Effusion

Types of pericardial effusions, subxiphoid cardiac view.Left image: typical effusion, middle image: clotted effusion , right image : with cardiac tamponade .

Fluid in Morrison Pouch

Fluid in Morrison Pouch

Fluid in Morrison Pouch

L

K

FF

Fluid in Morrison Pouch

Fluid In Pelvis

Fluid In Pelvis

Fluid In Pelvis

Fluid in Splenorenal Pouch

Fluid in Splenorenal Pouch

Fluid in Splenorenal Pouch

Hemothorax

KD

SPF

F

D

Pleural Fluid

Pleural Effusion

Right pleural effusion, transverse subxiphoid view

?

Is Pneumoperitoneum Can Be Detected By US?

YES

Pneumoperitoneum

Hollow Organs

StomachGall bladder

IntestinesUreters, Bladder

Solid Organs

LiverSpleenKidney

Pancreas

Vascular Injury

AortaVena Cava

Major Branches

Abdominal Organ Injury

Blunt InjuryAbdominal Trauma

• Spleen 25%• Liver 15%• Hollow viscus 15%– Ileum– Sigmoid

• Kidney 12%• Retroperitoneal 13%• Mesentery 5%

• Compression / deceleration • Crushing• Shearing• Avulsion

Solid-Organ Injuries (sonographic patterns)

I. Contusion : patchy ill defined non-linear echogenic area .

II. Subcapsular hematoma : under capsule.

III. Intra-parenchymal hematoma : well defined rounded hyperechoic area .

IV. Laceration : linear well defined hper / hypoechoic area.

V. Multiple lacerations/vascular injury (organic fracture, disorganization )

Liver laceration and hematoma

Subcapsular Liver hematoma

Liver laceration and hematoma

Splenic laceration

Spleen hematoma Subcapsular spleen hematoma

Splenic laceration

Preinephric and renal hematoma

Renal laceration

Subcapsular renal hematoma

References• Vicki E Nobil , Manual of emergency and critical care ultrasound , Cabridge university 2007

• Rosen, C. Ultrasound in Emergency Medicine. Emergency Medicine Clinics of North America. August 2004. Volume 22. Number 3.

• O. John Ma and James R. Mateer. Emergency Ultrasound. McGraw-Hill. Medical Publishing Division. 2003.

• Simon, B. Ultrasound in Emergency and Ambulatory Medicine. Mosby. 1997

• Temkin, BB. Ultrasound Scanning: Principles and Protocols. WB Saunders. 1993.• AIUM Practice Guideline for the Performance of the Focused Assessment With Sonography for Trauma

(FAST) Examination• Wolfang Dahnert• Ppt by Dr. Derhim Alfaqeeh Radiologist Consultant HO The Radiology

Dept University Of Science And Technology Hospital - Sana’a December 17, 2013

THANX