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ultrasound

Vascular

  • Abdominal aortic aneurysm
    • Aneurysm is a dilatation of more than 3 cm OR
    • an increase in diameter of 50% greater than original artery
    • The majority of the abdominal aortic aneurysms (AAA) are infrarenal
    • The correct measurement technique is outer wall to outer wall
  • Common iliac aneurysm
    • > 1.7 cm (male)
    • > 1.5 cm (female)

DDx for ↑ resistance waveforms

  • Peripheral artery; distal aorta
  • Proximal to stenosis/ occlusion
  • Renal transplant rejection

DDx for ↓ resistance waveforms

  • Organs: brain; liver; kidney; etc.
  • Placenta
  • AVM / AVF

Carotids

  • Surgical candidates
    • Symptomatic patients with stenosis > 70% (NASCET = North American Symptomatic Carotid Endarterectomy Trial)
    • Asymptomatic patients with stenosis > 60% (ACAS = American Carotid Atherosclerosis Study)
  • ICA occlusion: absence of blood flow; externalization of CCA
Features ICA ECA
Location Posterolateral Anteromedial
Size Larger Smaller
Branches None Several
Waveform ↓ resistance ↑ resistance
Temporal tap No Yes
% Stenosis PSV EDV PSV Ratio
Normal 70-100
50-69% >130 >1.8
70-95% >250 >100 >4
>95% Velocity falls

Renal Artery Stenosis

% Stenosis PSV RAR SAT Waveform
Normal <180 <0.1 Low resistance
<60% >180 <3.5 <0.1 Low resistance
>60% >180 >3.5 >0.1 Poststenotic turbulence
Doppler bruit or plaque

* Cannot use the RAR if:

  1. If AAA detected
  2. If aortic PSV > 90cm/s or < 40cm/s
  • If one of these conditions is present, look at the Renal Artery PSV only

Renal RI's

RI = (peak systolic velocity - end diastolic velocity ) / peak systolic velocity

  • the normal value is ≈ 0.60
  • > 0.70 is abnormal

Usefulness of RI is limited

Mesenteric

  • SMA stenosis
    • PT MUST BE FASTING
    • PSV > 275 cm/s indicates a > 70% diameter reduction
  • Post-prandially
    • The celiac artery remains a low resistance vessel
    • The SMA becomes low resistance, because now it needs more blood for digestion
    • If the SMA does not change dramatically after eating, there is a stenosis/occlusion
  • Low resistance abdominal arteries
    1. renal
    2. celiac
    3. hepatic
  • High resistance abdominal arteries
    1. Aorta
    2. fasting SMA
    3. fasting IMA

Lower Extremity Arterial

% Stenosis PSV PSV Ratio Waveform shape Waveform window
0% 70-120 Normal Triphasic Clear window
1-19% Normal Normal Triphasic Spectral broadening
20-49% 120-180 <2:1 ratio Triphasic Spectral broadening
50-99% >180 >2:1 ratio Loss of flow reversal Spectral broadening

Ankle Brachial Index

  • ABI < 0.95 at rest or following exercise is considered abnormal
  • ABI between 0.8 and 0.95 is mildly decreased
  • ABI between 0.5 and 0.8 is consistent with moderate disease/intermittent claudication
  • ABI < 0.5 indicates severe disease
  • Use the higher of the two ankle pressures for the ABI

Toe Brachial Index

  • 0.80 -0.90 normal
  • 0.20 -0.35 intermittent claudication
  • <0.20 rest pain/ischemia

Trifurcation Anatomy

Anatomy of the Trifurcation
AT = Anterior Tibial Artery
PT = Posterior Tibial Artery
PR = Fibular or Peroneal Artery

TIPS

Diagnosis Stent MPV RPV, LPV RHV
Normal 80-190 >30 one or both retrograde 80-190
Abnormal >190 or <80
>50 interval Δ
color bruit or stenosis
<30 antegrade >190

Thyroid

Anatomy

Legend:
  * T - trachea
  * t - thyroid lobes
  * i - isthmus
  * c - common carotid artery
  * j - jugular vein
  * 1 - sternocleidomastoid muscle
  * 2 - longus colli muscle
  * 3 - scalenus anterior muscle
Legend:
  * T - trachea
  * t - thyroid lobes
  * i - isthmus
  * c - common carotid artery
  * j - jugular vein
  * 1 - sternocleidomastoid muscle
  * 2 - longus colli muscle
  * 3 - scalenus anterior muscle
Legend:
  * T - trachea
  * t - thyroid lobes
  * i - isthmus
  * c - common carotid artery
  * j - jugular vein
  * 1 - sternocleidomastoid muscle
  * 2 - longus colli muscle
  * 3 - scalenus anterior muscle
Hover over image for legend

Recommendations for Thyroid Nodules 1 cm or Larger in Maximum Diameter

US Feature Recommendation
Solitary nodule
Microcalcifications Strongly consider US-guided FNA if ≥ 1 cm
Solid (or almost entirely solid) or coarse calcifications Strongly consider US-guided FNA if ≥ 1.5 cm
Mixed solid and cystic or almost entirely cystic with solid mural component Consider US-guided FNA if ≥ 2 cm
None of the above but substantial growth since prior US examination Consider US-guided FNA
Almost entirely cystic and none of the above and no substantial growth (or no prior US) US-guided FNA probably unnecessary
Multiple nodules Consider US-guided FNA of one or more nodules, with selection prioritized on basis of criteria (in order listed) for solitary nodule
  • Note: FNA is likely unnecessary in diffusively enlarged gland with multiple nodules of similar US appearance without intervening parenchyma. Presence of abnormal lymph nodes overrides US features of thyroid nodule(s) and should prompt US-guided FNA or biopsy of lymph node and/or ipsilateral nodule.

Liver

Anatomy

Legend:
  * CL = caudate lobe of the liver
  * 1 = diaphragm
  * F = fissure for the ligamentum venosum
  * 2 = gallbladder
  * HV = hepatic vein
  * IVC = inferior vena cava
  * 3 = right kidney
  * MPV = main portal vein
  * RHD = right hepatic duct
  * RPV = right portal vein
  * CBD = common bile duct
  * RRA = right renal artery
  * P = pancreas
Legend:
  * CP = caudate process
  * F = fissure for the ligamentum venosum
  * IVC = inferior vena cava
  * LPV = left portal vein
  * MHV = middle hepatic vein
  * RHV = right hepatic vein
  * RPV = right portal vein
  * LT = ligamentum teres
  * MS = medial segment of left lobe
  * LS = lateral segment of left lobe
Hover over image for legend

  • Ligamentum teres → obliterated umbilical vein
  • Ligamentum venosum → remnant of ductus venosus
  • Common duct is straighter and more variable in diameter than hepatic artery
  • Right hepatic artery is normally between portal vein and bile duct
  • Upper limit of normal for intrahepatic bile ducts = 2 mm

Hyperechoic Liver Mass

  • Hemangioma
  • HCC
  • Focal Fat

Thickened Gallbladder Wall

Normal GB wall < 3mm

  • heart failure
  • hypoproteinemia
  • edema-forming states
  • hepatitis
  • cirrhosis
  • portal hypertension
  • lymphatic obstruction
  • GB cancer
  • adenomyomatosis
  • cholecystitis

Upper Abdominal Vascular Anatomy

Legend:
  * 1 = gastroesophageal junction
  * 2 = crus of the diaphragm
  * 3 = celiac axis
  * 4 = superior mesenteric artery
Legend:
  * 1 = hepatic vein
  * 2 = caudate lobe of the liver
  * 3 = portal vein
  * 4 = pancreas
  * 6 = gastric antrum
  * 7 = right renal artery
Legend:
  * 1 = abdominal aorta
  * 2 = hepatic artery
  * 3 = splenic artery
  * 4 = celiac axis
  * 5 = right renal artery coursing behind the inferior vena cava
Legend:
  * 1 = abdominal aorta
  * 2 = confluence of the splenic vein and the superior mesenteric vein
  * 3 = splenic vein
  * 4 = superior mesenteric artery
  * 5 = left renal vein
  * 6 = tail and body of the pancreas
Legend:
  * 1 = abdominal aorta
  * 2 = superior mesenteric artery
  * 3 = hepatic artery arising from the superior mesenteric artery
  * 4 = confluence of the splenic and superior mesenteric veins
  * 5 = left renal vein, identified between the superior mesenteric artery and the abdominal aorta
Hover over image for legend

Spleen

  • Upper limit of normal → 13 cm

Hypoechoic Masses

  • lymphoma
  • mets
  • sarcoid
  • infarcts
  • infection

Pancreas

Anatomy

Legend:
  * 1 = splenic vein
  * 2 = gastroduodenal artery
  * 3 = common bile duct
  * GB = gallbladder
  * P = pancreatic head
  * SP = spine
  * ST = stomach
  * U = uncinate process
  * 4 = superior mesenteric vein (SMV)
  * 5 = superior mesenteric artery (SMA)
  * 6 = left renal vein
  * Ao = aorta
  * D = duodenum
  * IVC = inferior vena cava
  * LLL = left lobe of the liver
Legend:
  * 1 = splenic vein
  * 2 = gastroduodenal artery
  * 3 = common bile duct
  * GB = gallbladder
  * P = pancreatic head
  * SP = spine
  * ST = stomach
  * U = uncinate process
  * 4 = superior mesenteric vein (SMV)
  * 5 = superior mesenteric artery (SMA)
  * 6 = left renal vein
  * Ao = aorta
  * D = duodenum
  * IVC = inferior vena cava
  * LLL = left lobe of the liver
Hover over image for legend

Renal

Bosniak Classification of Renal Cystic Disease

  • Category I — Category I lesions are simple benign cysts showing homogeneity, water content, and a sharp interface with adjacent renal parenchyma, with no wall thickening, calcification, or enhancement.
  • Category II — This category consists of cystic lesions with one or two thin (≤ 1 mm thick) septations or thin, fine calcification in their walls or septa (wall thickening > 1 mm advances the lesion into surgical category III) and hyperdense benign cysts with all the features of category I cysts except for homogeneously high attenuation. A benign category II lesion must be 3 cm or less in diameter, have one quarter of its wall extending outside the kidney so the wall can be assessed, and be nonenhancing after contrast material is administered.
  • Category IIF — This category consists of minimally complicated cysts that need follow-up. This is a group not well defined by Bosniak but consists of lesions that do not neatly fall into category II. These lesions have some suspicious features that deserve follow-up up to detect any change in character.
  • Category III — Category III consists of true indeterminate cystic masses that need surgical evaluation, although many prove to be benign. They may show uniform wall thickening, nodularity, thick or irregular peripheral calcification, or a multilocular nature with multiple enhancing septa. Hyperdense lesions that do not fulfill category II criteria are included in this group.
  • Category IV — These are lesions with a nonuniform or enhancing thick wall, enhancing or large nodules in the wall, or clearly solid components in the cystic lesion. Enhancement was considered present when lesion components increased by at least 10 H.

Hydronephrosis

  • Grade 1 - minimal separation of renal sinus
  • Grade 2 - distention of collecting system
  • Grade 3 - marked distention with cortical thinning

Lesions That Simulate Cysts

  • Calyceal Diverticulum
  • Aneurysm/Pseudoaneurysm
  • Lymphoma
  • Upper Pole Duplication

Prostate

Anatomy

  • peripheral zone (hyperechoic; develops into carcinoma)
  • transitional zone (periurethral; hypoechoic; ↑ BPH)

Prostate carcinoma

  • hypoechoic lesion in peripheral gland (70%); nodular or diffusely infiltrative
  • DDX = prostatitis; fibrosis; infarct; BPH; correlate with PSA/ DRE and BX
  • normal PSA < 4 ng/mL

BPH

  • enlargement of transitional zone; inhomogeneity; Ca2+

Prostatic cysts

  • Midline: utricle cyst; Muellerian duct cysts; ejaculatory duct cysts
  • Eccentric/ paramedian: seminal vesicle cysts; retention cysts; cystic BPH

Scrotal

Extra-testicular masses

  • Spermatocele: most common extratesticular mass; ↑ head of epididymis
  • Epididymal cysts: head or tail of epididymis
  • Adenomatoid tumor: #1 extra-testicular neoplasm; most common tumor of epididymis (> sarcoma; leiomyosarcoma; metastases)
  • Rhabdomyosarcoma: ↑ children
  • Hydroceles: fluid within tunica vaginalis; may develop cholesterol crystals → internal echoes (DDX = pyocele; hematocele)
  • Varicocele: dilated peritesticular veins (= pampiniform plexus); left (85%) > right (venous drainage); ↑ infertility
  • Tunica albuginea cysts

Intra-testicular masses

  • Testicular cysts: rare; ↑ elderly; ↑ near mediastinum (tunica albuginea)
  • Tubular ectasia of rete testis: usually bilateral; ↑ spermatoceles and intratesticular cysts
  • Seminoma: most common germ cell tumor; radiosensitive; ↑ young males; homogeneously hypoechoic
  • Teratomas: complex cystic masses; benign (children) or malignant (adult)
  • Embryonal cell carcinoma and choriocarcinoma: malignant; heterogeneous
  • Sertoli-Leydig cell tumors: rare; non-germ cell (= stromal) tumors; solid masses; < 6 years
  • Epidermoid cysts: benign; only ectodermal derivatives
  • Metastases: lymphoma; leukemia; prostate > lung, colon
  • Other lesions: focal orchitis; infarcts; atrophy; hematomas; abscesses

Testicular microlithiasis

  • > 5 Ca2+ per image; ↑ germ cell tumors

Testicular torsion

  • ↑ risk with bell-clapper deformity (abnormal tunica vaginalis suspended by spermatic cord); venous obstruction→ arterial obstruction → ischemia; DX w/in 6 hrs;↓ BF

Epididymo-orchitis

  • inflammatory hyperemia with testicular enlargement and ↓ echogenicity

DDx Focal Hypoechoic Mass

  • tumor
    • seminomas → homogeneously hypoechoic
    • non-seminomas → heterogeneous
  • infarct
  • focal atrophy
  • focal orchitis
  • hematoma
  • abscess
  • sarcoid
  • contusion
ultrasound.txt · Last modified: 2017/07/07 18:30 (external edit)