Exam 1: Values + condensed version

Sensitivity Formula

Number of true positive tests

Number of all positive tests by gold standard

Specificity Formula

Number of true negative tests

Number of all negative tests by gold standard

Positive Predictive Value (PPV) Formula

Number of true positive tests

Number of all positive noninvasive tests

Negative Predictive Value (NPV) Formula

Number of true negative tests

Number of all negative noninvasive tests

Accuracy Formula

Total number of correct tests

Total number of all tests

Celiac Artery PSV

101 cm/sec

Celiac Artery RI

0.7

70% Celiac Artery Stenosis PSV

≥ 200 cm/sec

Celiac Artery PSV with MALS

> 250 cm/sec during expiration that normalizes with inspiration

SMA PSV

113 cm/sec

70% SMA Stenosis PSV

≥ 275 cm/sec

IMA PSV

141 cm/sec

IMA Stenosis PSV

> 200 cm/sec

Left Gastric Vein (coronary vein) Diameter

> 6 mm

Main Portal Vein Diameter

≤ 13mm (resting)

≤ 16 mm (deep inhalation/valsalva)

Main Portal Vein PSV

16-31 cm/sec

Hepatic Vein Diameter

6 mm

≤ 9 mm (when CHF is present)

Hepatic Vein PSV

20-39 cm/sec

Hepatic Artery PSV

70-120 cm/sec

Hepatic Artery RI

0.5 - 0.7

Splenic Vein Diameter

10 mm

Splenic Vein PSV

9-30 cm/sec

SMV Diameter

10 mm

SMV PSV

8-40 cm/sec

IVC Diameter

15-25 mm

valsalva = max diameter

IVC PSV

44-118 cm/sec

Increases with inspiration

Portal Pressure Formula

IVC pressure - portal vein pressure

Portal Vein Pressure

5-10 mmHg

≥ 15 mmHg = clinically significant

Recanalized Paraumbilical Vein Diameter

> 3 mm

Recanalized Paraumbilical Vein PSV

> 5 cm/sec

Gallbladder Varices Diameter

3-8 mm

TIPS Shunt PSV

90-190 cm/sec

TIPS Shunt Stenosis Findings

< 50 cm/sec velocity within stent

Focal area velocity increase > 200 cm/sec

> 50 cm/sec velocity change in same portion of stent compared to past exams

Normal Kidney Size

9-13 cm

No more than 2 cm difference between left & right

Aorta PSV at Renal A. Level

60-100 cm/sec

Low resistant

Renal A. Origin PSV

74-127 cm/sec

Distal Renal A. PSV

70-90 cm/sec

Renal A. Sinus PSV

30-50 cm/sec

Renal A. Cortex PSV

10-20 cm/sec

Renal A. PSV Criteria for ≥ 60% Stenosis

> 180 cm/sec (without angle correct)

> 150 cm/sec (with angle correct & turbulence)

Renal Aortic Ratio (RAR) Formula

PSV renal artery

PSV aorta

Angle independent

Normal RAR

< 3.5

Normal Acceleration Time

< 0.1 seconds

Normal Acceleration Index

> 3.78 kHz/sec/MHz

Normal Acceleration

> 291 cm/sec^2

Gold Standard for Vascular Imaging

Angiography

Validity

Ability of a test to distinguish between who has the disease and who does not

Accuracy

Degree of closeness of a test result to the actual value

Percentage of overall correct results

Must lie between sensitivity & specificity and PPV & NPV

Reliability

Consistency of obtaining similar results under similar conditions - reflects accuracy over time

Increasing Cut-Off Values

Improves specificity

More true negatives

Decreasing Cut-Off Values

Improves sensitivity

More true positives

Celiac Artery Occlusion

Results in SMA collaterals diverting blood through gastroduodenal artery toward the liver and spleen

Replaced Right Hepatic Artery

Right hepatic artery branches off something else besides celiac artery - usually SMA

Hepatic Artery Retrograde Flow

Due to celiac artery occlusion

Blood flows towards splenic artery - RABT color pattern

Pre-Prandial SMA Doppler

Post-Prandial SMA Doppler

Common Trunk Variant

Celiac and SMA come off common trunk

Prominent IMA

Due to SMA occlusion

Acute Mesenteric Ischemia

Thrombosis of one or more mesenteric vessels

Life threatening - requires immediate intervention

Severe cramping/pain - disproportional pain

Chronic Mesenteric Ischemia

Low resistant pre-prandial doppler signals

70% occlusion of 2/3 splanchnic arteries required for diagnosis (celiac, SMA, IMA)

Epigastric pain after eating - fear of food, weight loss, decreased nutrition

Compensatory Flow

Elevated velocities in normal collateral vessels

No stenotic profile seen

Dissection

Separation of channels - flap line

To and fro flow

Median Arcuate Ligament Syndrome (MALS)

Compression of celiac axis during exhalation by median arcuate ligament

Pain relieved by inhalation

Evaluate in supine & upright positions and with inspiration & expiration

Pre-Hepatic/Inflow Vessels

Portal Vein

Hepatic Artery

Intrahepatic/Sinusoidal Vessels

Sinusoids/capillaries

Hepatocytes

Post-Hepatic/Outflow Vessels

Central Veins

Sublobular Veins

Hepatic Veins

IVC

Left Gastric Vein (coronary vein) Doppler Flow

Hepatofugal

Main Portal Vein Doppler Waveform

Monophasic continuous waveform

Hepatopetal flow (antegrade flow)

Hepatic Vein Doppler Waveform

Triphasic

Antegrade & retrograde flow - cardiac pressure changes

Hepatic Vein Doppler

S wave: ventricular systole

D wave: atrial filling

A wave: atrial contraction

Inspiration depresses systolic wave

Exhalation augments systolic wave

Valsalva diminishes pulsatility

Hepatic Artery Doppler Waveform

Hepatopetal

Low resistant monophasic pan-diastolic forward flow

Hepatic Buffer Response

When PV flow increases, HA flow decreases (post-prandial)

Splenic Vein Doppler Waveform

Hepatopetal flow

Continuous monophasic with slight respiratory variation

SMV Doppler Waveform

Hepatopetal flow

Continuous monophasic with slight respiratory variation

Portal HTN

Increased pressure in portal venous system

Not diagnosed with spectral Doppler -> diagnosed with gray scale & color

Causes of Portal HTN

Hepatitis C

Hepatitis B

Alcoholic cirrhosis

Primary Biliary Cirrhosis

Autoimmune Hepatitis

Hereditary Hematochromatosis

Schistosomiasis

Portal HTN 2D Findings

Large pulmonary vein

Collaterals

Splenomegaly

Ascites

Enlarged hepatic artery

Portal HTN Doppler Findings

Slow, hepatofugal flow in portal vein

Cirrhosis

End-stage liver disease

Cirrhosis Findings

Portalization of hepatic veins

Collaterals

Hepatofugal flow in portal vein & splenic vein

Coronary Vein Collateral

Can lead to esophageal varices

Recanalized Paraumbilical Vein

Ligamentum teres recanalizes

Courses from left portal vein to anterior abdominal wall

Hepatofugal flow

Splenorenal Shunt

Prominent veins at splenic hilum

Hepatofugal flow in splenic vein

Gastroesophageal Veins/Esophageal Varices

Originate from gastroesophageal junction posterior to left liver lobe

Due to hepatofugal flow in coronary vein shunt

High risk of rupture

AV Fistula

Arterialized portal vein flow - hepatic artery to portal vein shunting

Leads to portal HTN

AV Fistula Findings

Large anechoic spaces

Increased portal vein pulsatility & velocities

Aterialization of the Liver

Max portal vein pressure leads to increased hepatic artery flow

Cavernous Transformation

Due to chronic portal vein thrombosis

Occurs within 6 days after thrombotic event

Absent portal vein flow

Formation of new peri-portal vessels around portal vein

Hepatopetal flow within serpentine vessels

Budd-Chiari Syndrome

Hepatic vein/liver outflow obstruction

Causes increased sinusoidal pressure

Budd-Chiari Syndrome Findings

Hepatic vein thrombosis/post-sinusoidal thrombosis

Monophasic, reduced/reversed flow in portal vein

Enlarged caudate lobe

Ascites

Splenomegaly

Cardiac Cirrhosis

Liver edema caused by congestive heart failure

Portal Vein with Cardiac Cirrhosis

Pulsatile

Biphasic

Hepatic Veins with Cardiac Cirrhosis

Compromised flow - over congestion

"w" pattern

TIPS Shunt

Stent between portal vein & hepatic vein

(commonly right portal vein and right hepatic vein)

TIPS Shunt Normal Findings

No focal aliasing

Hepatofugal flow in portal veins beyond stent

TIPS Shunt Abnormal Findings

Focal aliasing

Velocity changes

Antegrade flow in right & left portal veins

Retrograde flow in hepatic vein

Developing ascites or collaterals

TIPS Shunt Occlusion Findings

Hepatopetal flow in right & left portal veins

Hepatofugal flow in main portal vein

Resistive Index

Resistance of the end/target organ

Orthotopic Liver Transplant

Whole liver is transplanted from a deceased donor

Piggyback IVC Anastomosis

Donor supra hepatic IVC attached to recipients hepatic venous confluence