Old Material - QA, Liver/Portal, Mesenteric, Renal, Physiologic Testing, Venous Insufficiency/PPG/APG/Non-Atherosclerotic Pathologies

Gold Standard

Well-established, reliable diagnostic method used as a reference

True Positive (TP)

Those who have disease and a positive test

Ultrasound shows disease, gold standard shows disease

True Negative (TN)

Those who do not have disease and a negative test

Ultrasound shows no disease, gold standard shows no disease

False Positive (FP)

Those who do not have disease and a positive test

Ultrasound shows disease, gold standard shows no disease

False Negative (FN)

Those who have disease and a negative test

Ultrasound shows no disease, gold standard shows disease

Sensitivity

Ability of test to correctly detect patients with disease compared to the gold standard - positive sonogram with positive gold standard

Sensitivity Formula

Number of true positive tests

Number of all positive tests by gold standard

Specificity

Ability of test to correctly detect patients without disease compared to the gold standard - negative sonogram with negative gold standard

Specificity Formula

Number of true negative tests

Number of all negative tests by gold standard

Positive Predictive Value (PPV)

Probability that a positive test result reflects the actual presence of disease

Portion of patients with a positive test that have disease

Positive Predictive Value (PPV) Formula

Number of true positive tests

Number of all positive noninvasive tests

Negative Predictive Value (NPV)

Probability that a negative test result reflects the actual absence of disease

Portion of patients with a negative test that do not have disease

Negative Predictive Value (NPV) Formula

Number of true negative tests

Number of all negative noninvasive tests

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

Accuracy Formula

Total number of correct tests

Total number of all tests

Pre-Hepatic/Inflow Vessels

Portal Vein

Hepatic Artery

Post-Hepatic/Outflow Vessels

Hepatic Veins

IVC

Main Portal Vein

Junction of splenic vein & SMV

Brings blood from bowel and spleen into liver

Main Portal Vein Doppler Waveform

Monophasic continuous waveform

Hepatopetal flow (antegrade flow)

Main Portal Vein PSV

16-31 cm/sec

Slight respiratory variation

-> breath in = decreased velocity

-> breath out or eating = increased velocity

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 Vein PSV

20-39 cm/sec

Hepatic Artery

Right branch of celiac trunk

Hepatic Artery Doppler Waveform

Hepatopetal

Low resistant monophasic pan-diastolic forward flow

Hepatic Artery PSV

70-120 cm/sec

Hepatic Artery RI

0.5 - 0.7

Splenic Vein Doppler Waveform

Hepatopetal flow

Continuous monophasic with slight respiratory variation

Splenic Vein PSV

9-30 cm/sec

IVC PSV

44-118 cm/sec

Increases with inspiration

Sub-Xiphoid/Transverse Epigastric & Left Sagittal

Left Hepatic V at IVC: blue

Ascending Left Hepatic V: red

Hepatic Artery: red

Porta Hepatis: red

Portal Confluence: blue

Splenic Vein: red

Right Subcostal Margin

Porta hepatis, MPV, anterior RPV, HA: red

Posterior RPV : blue

Right Intercostal

Porta hepatis: red

Portal-Splenic confluence: red

Left Coronal Oblique

Splenic vein: blue

Portal HTN

Increased pressure in portal venous system

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

Portal HTN 2D Findings

Large pulmonary vein

Collaterals

Splenomegaly

Ascites

Enlarged hepatic artery

Portal HTN Doppler Findings

Slow, hepatofugal flow in portal 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

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

TIPS Shunt

Stent between portal vein & hepatic vein

(commonly right portal vein and right hepatic vein)

TIPS Shunt Purpose

Decompress portal system

Reduces risk of variceal rupture & ascites

Treats hepatic venous outflow obstructions

TIPS Shunt PSV

90-190 cm/sec

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 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

TIPS Shunt Occlusion Findings

Hepatopetal flow in right & left portal veins

Hepatofugal flow in main portal vein

Protocol for Mesenteric Study

RUQ first - eliminate GB as pain source

Pre and post-prandial images - 2D, color, spectral

Aorta at level of celiac axis and SMA

Origin of celiac axis

Origin of SMA

Origin of IMA

Celiac Artery

Celiac Artery Doppler Waveform

Low resistant

Celiac Artery PSV

101 cm/sec

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

SMA

Pre-Prandial SMA Doppler

Post-Prandial SMA Doppler

SMA PSV

113 cm/sec

Common Trunk Variant

Celiac and SMA come off common trunk

IMA

IMA PSV

141 cm/sec

Prominent IMA

Due to SMA occlusion

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

Celiac Artery PSV with MALS

> 250 cm/sec during expiration that normalizes with inspiration

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

Small Vessel Disease

Fasting low resistant waveform

Stenosis

Stenotic profile

Treated with stents

Right Renal Artery

Posterior to IVC and RRV

Left Renal Artery

Normal Renal Artery Spectral Waveform

Rapid upstroke

Early systolic peak

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

0-59% Stenosis Waveform

60-70% Stenosis Waveform

> 80% Stenosis Waveform

PSV Criteria for ≥ 60% Stenosis

> 180 cm/sec (without angle correct)

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

Direct Renal Artery Exam

Uses velocities & RAR

Normal RAR

< 3.5

Indirect Renal Artery Exam

Uses acceleration time, acceleration index, and waveform assessments

Acceleration Time (AT)

Time it takes for the to reach early systolic peak

Normal Acceleration Time

< 0.1 seconds

Normal Acceleration

> 291 cm/sec^2

Normal Renal Vein Doppler

Continuous pattern with mild respiratory variations

Sonographic Appearance of Renal Vein Thrombosis

Enlarged kidney

Enlarged vein with internal echoes

Lack of color fill

Biphasic/high resistant arterial signal

Acute Tubular Necrosis (ATN)

Due to ischemia that develops between recipient removal to donor transplant

Common with cadaver donor kidneys

Occurs early post-op

Appearance of Acute Tubular Necrosis (ATN)

Enlarged kidney

Loss of corticomedullary boarders

Parenchymal Graft Failure Causes

Acute tubular necrosis (ATN)

Rejection

Cyclosporin toxicity

Vascular Transplant Failure Causes

Thrombosis

Stenosis

Urological Transplant Failure Causes

Obstruction

Extrinsic compression

Fluid collections

Symptoms of Renal Transplant Rejection

Sudden cessation of urine output (anuria)

Decreased urine output (oliguria)

Increased serum creatinine, protein, or lymphocytes in urine

Hypertension

Swelling or tenderness of the graft

Hyperacute Transplant Rejection

Minutes to hours

Rare

Due to faulty crossmatching tests

Completely destroys graft

Removed immediately

Acute Transplant Rejection

2 weeks - 3 months

Common in cadaver donor kidneys

Appearance of Acute Transplant Rejection

Enlarged kidney

Loss of corticomedullary boarder

Decrease in diastolic flow or flow reversal

RI > 0.8

Chronic Transplant Rejection

3 months - years