Diagnostic ultrasound ( PDFDrive )

456 PART II Abdominal and Pelvic Sonography
A
B
FIG. 12.27 Poststenotic Turbulence. (A) Spectral waveform at site of stenosis shows very high diastolic velocities of greater than 500 cm/
sec. Color portion of the image shows color bruit consisting of color outside the vessel near the stenosis site. Color bruit is believed to be caused
by tissue vibration. (B) Spectral waveform shows the typical “spike hairdo” waveform caused by poststenotic turbulence. There is mirror-image
artifact. Because of the very high velocities, the baseline of the waveform has been placed at the bottom, causing the “low below the baseline”
to appear at the top of the tracing. Flow below the baseline is also typical of turbulence.
A
B
FIG. 12.28 Takayasu Arteritis. Patient, 34 years old, with blood pressure discrepancy between the right and left arms. Subsequent workup
showed occlusion of the left subclavian artery and severe stenosis of the right renal artery origin. Two years later, the arteritis lared and the patient
developed severe stenosis of the celiac artery and the superior mesenteric artery (SMA). (A) Mesenteric duplex shows elevation of both systolic
and diastolic velocities. (B) Curved reformatted computed tomography image shows moderate narrowing of the SMA origin. Note the wall thickening
of the SMA at its origin caused by mural inlammation. The patient was treated medically.
in whom IVC evaluation with ultrasound has a better opportunity
to provide good diagnostic information.
Anatomy
he IVC can be divided into several segments. he most proximal
(i.e., central) segment is the suprahepatic (posthepatic), which
is short and intrathoracic. In adults this segment is approximately
2.5 cm in length and has the hepatic veins as tributaries. he
next segment is intrahepatic, with accessory hepatic and caudate
veins as tributaries. he next segment is the infrahepatic/
suprarenal, which has the renal veins as tributaries. he last
segment is infrarenal, which is the longest segment and has the
right gonadal vein as a tributary. Proceeding distally, the IVC
divides into the common iliac veins. he let common iliac vein