Ultrasound

Table of Contents

Normal Pediatric Ultrasound Measurements

LIVER/RUQ

Sources:

McNaughton DA, Abu-Yousef MM. Doppler US of the liver made simple. Radiographics. 2011 Jan-Feb;31(1):161-88. doi: 10.1148/rg.311105093. Erratum in: Radiographics. 2011 May-Jun;31(3):904. PMID: 21257940.

Crossin JD, Muradali D, Wilson SR. US of liver transplants: normal and abnormal. Radiographics. 2003 Sep-Oct;23(5):1093-114. doi: 10.1148/rg.235035031. PMID: 12975502.

Normals

Gallbladder Wall<3mm
CBD<6mm, add 1mm per decade >70 years
MPV<13mm
IVC12-17mm
Hepatic Artery RI0.55-0.7

TIPS Evaluation

Direct Signs of TIPS malfunctionIndirect signs
Shunt velocity <90cm/s OR >/= 190cm/s
Increase or decrease in velocity by >50cm/s		MPV velocity >30cm/s
Collateral vessels (new, increased)
Ascites (new, increased)
R-L portal venous flow reversal (hepatopetal)
Malfunction MC at the cephalic portion of the stent
  • Variations in TIPS placements

Liver transplant evaluation

Complications

  • IVC stenosis/thrombosis
  • Biliary strictures, stones or sludge, dysfunction of the sphincter of Oddi, and recurrent disease
    • Most within 3-6 months of transplant
  • Parenchymal infarcts and abscesses 2/2 hepatic artery complications
  • Fluid collections and ascites

Normal findings

RI0.5-0.7
Hepatic arteryRapid systolic upstroke with continuous diastolic flow
Hepatic veinPhasic flow pattern
Portal veinContinuous hepatopetal flow
Low RI = vascular shunting or proximal stenosis; High RI = distal stenosis
  • Normal MPV waveforms
  • Normal hepatic vein and artery waveforms

RETROPERITONEAL ULTRASOUND

Source: Sugi MD, Joshi G, Maddu KK, Dahiya N, Menias CO. Imaging of Renal Transplant Complications throughout the Life of the Allograft: Comprehensive Multimodality Review. Radiographics. 2019 Sep-Oct;39(5):1327-1355. doi: 10.1148/rg.2019190096. PMID: 31498742.

Renal cortexLess echogenic than liver
>6mm thickness
Medullary pyramidsLess echogenic than cortex
Renal sinusMore echogenic than cortex
Parenchymal thickness15-20mm
Renal size10-14 cm long in males
9-13 cm long in females
Adults

Renal Transplant

Complications

Renal artery RINormal 0.5-07
>0.7 indicated graft dysfunction
Parenchymal edemaGraft dysfunction (nonspecific)
Renal vein thrombosis/stenosisReversal of diastolic flow
Renal artery thrombosis/stenosisPSV >200cm/s
>2:1 velocity ∆ between segments
Post-stenotic spectral widening
Parvus et tardus waveform distal to stenosis
PseudoanuerysmYing/yang sign
AVFHigh-velocity, low resistance flow within the artery
May see vibration “mosaic” color on Doppler

Graft dysfunction

  • ATN/Rejection
  • Nephrotoxicity (drugs)
  • Recurrent disease
  • Pyelonephritis
  • Reversal of diastolic flow in renal vein thrombosis
  • Elevated PSV in renal artery stenosis
  • Upstream parvus et tardus waveform in renal artery stenosis

Perinephric fluid collections

CollectionTimelineImaging
Hematoma0-5 daysComplex heterogenous collection
Internal septations/retracting clot
Abscesswks-moIncreased peripheral blood flow on Doppler
Thick wall
Urinoma0-10 daysSimple collection with anechoic fluid
Lymphocele2wk-6moFluid collection ± thin internal septa, usually adjacent to kidney

Timeline of post-transplant complications

Grading Fetal/Pediatric Hydronephrosis

Source: Nature

Female Reproductive

Pre-menopausal endometrial thickness3-15mm
Post-menopausal endometrial thicknessNo bleeding: <8mm
Bleeding: <5mm
Pre-menopausal ovarian volume4-16mL
Post-menopausal ovarian volume1.2-5.8mL

Adnexal Cysts

Source: Levine D, Patel MD, Suh-Burgmann EJ, et al. Simple Adnexal Cysts: SRU Consensus Conference Update on Follow-up and Reporting. Radiology. 2019;293(2):359-371. doi:10.1148/radiol.2019191354

Pre-menonpausal Female

Post-menopausal Females

Follow-up Exam Guidelines

First Trimester Ultrasound

Sources

RSNA: Normal and Abnormal US Findings in Early First-Trimester Pregnancy: Review of the Society of Radiologists in Ultrasound 2012 Consensus Panel Recommendations

Doubilet PM, Benson CB, Bourne T, Blaivas M; Society of Radiologists in Ultrasound Multispecialty Panel on Early First Trimester Diagnosis of Miscarriage and Exclusion of a Viable Intrauterine Pregnancy, Barnhart KT, Benacerraf BR, Brown DL, Filly RA, Fox JC, Goldstein SR, Kendall JL, Lyons EA, Porter MB, Pretorius DH, Timor-Tritsch IE. Diagnostic criteria for nonviable pregnancy early in the first trimester. N Engl J Med. 2013 Oct 10;369(15):1443-51. doi: 10.1056/NEJMra1302417. PMID: 24106937.

General Principles

  • Discriminatory zone of beta-hcg: >2,000-3,000
  • Should see yolk sac by 5.5 weeks
  • Should see fetal pole by 6 weeks
  • Should see yolk sac once gestational sac is 8mm
  • Should see fetal pole once gestational sac is 16mm
  • Fetal demise if gestational sac 25mm and no fetal pole

SRU Criteria

Poor prognosticators of early pregnancy

Pregnancy of Unknown Location

Expectant management should only be recommended in asymptomatic patients 

Increasing pain, hemorrhage, increasing or stable hCG DO NOT RECOMMEND EXPECTANT MANAGEMENT 

Serial hCG q48hrs and TVUS required

  • Nonviable IUP most likely when hCG >2000 mIU/mL 
    • hCG 2000-3000 mIU/mL 
      • Likelihood of viable IUP is around 2% 
      • Nonviable IUP 38x as likely as viable IUP and 2x as likely as ectopic pregnancy 
      • Follow up with US and repeat hCG testing 
    • hCG >3000 mIU/mL 
      • Viable IUP is possible but unlikely <0.5% 
      • Nonviable IUP is most likely 
        • At least one F/u hCG and TVUS 
      • Ectopic 70x more likely than viable IUP  

Ectopic Pregnancy

General Principles

  • Patients with ectopic have slower hCG rise than women with normal IUP 
    • <53% hCG increase over 48 hours, pregnancy almost always nonviable (99% sensitivity) 
  • Sensitivity and specificity of transvaginal ultrasound findings 
    • Extrauterine live embryo with cardiac activity – 100% specific 
    • Adnexal mass separate from ovary 
      • Yolk sac (YS) and embryo – most specific 
      • Tubal ring with YS only OR no central identifying features – less specific 
      • Complex extra ovarian adnexal mass 
    • Ring of fire sign
      • Not specific – more common with corpus luteum 
    • Complex pelvic free fluid – rupture 
      • 86-93% PPV with abnormal hCG

Intrauterine Findings in Ectopic Pregnancy

  • SRU 2013 
    • For pregnancy of unknown location, intrauterine round or oval fluid collection is much more likely to be an IUP than a pseudo gestational sac or decidual cyst
  • Pseudogestational sac
    • 10-20% of ectopic pregnancies
    • Surrounding thick decidual reaction and absent arterial flow
    • Angular or teardrop appearance
    • Central location distinguishes from decidual cysts and intradecidual sac
Pseudogestational sac (source – Radiopaedia)

Carotid Ultrasound

Look at the plaque, degree of stenosis, and carotid waveforms 

Source: Grant EG, Benson CB, Moneta GL, Alexandrov AV, Baker JD, Bluth EI, Carroll BA, Eliasziw M, Gocke J, Hertzberg BS, Katanick S, Needleman L, Pellerito J, Polak JF, Rholl KS, Wooster DL, Zierler RE. Carotid artery stenosis: gray-scale and Doppler US diagnosis–Society of Radiologists in Ultrasound Consensus Conference. Radiology. 2003 Nov;229(2):340-6. doi: 10.1148/radiol.2292030516. Epub 2003 Sep 18. PMID: 14500855.