(Ultrasound Review) Differentiating total versus near total occlusion of the internal carotid artery (ICA) is a familiar diagnostic dilemma. Patients with near total occlusion remain at high risk for embolic stroke and are surgically treated, while those with an occluded ICA are at minimal risk for embolic phenomena and are treated medically for hypoperfusion, according to researchers at the West Los Angeles Veterans Administration Medical Center in California.
The purpose of this prospective study was to evaluate ultrasonography and magnetic resonance angiography (MRA) in differentiating these two stages of atherosclerosis. The results were published in the November issue of Radiology.
Two hundred and seventy-four consecutive patients underwent catheter angiography and MRA of the extra- and intracranial carotid arteries and duplex ultrasound of the extracranial carotid arteries. Carotid endarterectomy was performed when Doppler ultrasound showed a peak systolic velocity (PSV) greater than 250 cm/sec and an ICA/CCA PSV of 4.0. Previous research by this group determined that these criteria indicated a greater than 70% stenosis. Thirty-seven patients were shown to have a total occlusion and there were 21 near total occlusions.
"Ultrasound depicted all total occlusions; MRA depicted 34 (92%). Ultrasound depicted 18 of 21 (86%) near occlusions; MRA depicted all," they wrote.
Ultrasound was useful in differentiating between patients with focal stenosis versus those with diffuse disease, but MRA was not capable of differentiating these two disease types. There were three patients with distal ICA occlusion that were correctly diagnosed with ultrasound. When duplex waveforms in the ICA are low-velocity with high-resistance this suggests severe disease in the more distal portion of the ICA, they said.
"Assuming ultrasound is the initial imaging examination, when occlusion is diagnosed, MRA can depict it. If occlusion is confirmed, no further imaging is necessary," they said. In this study there were eight patients (13.7%) with diffuse non-focal disease and according to the authors, these patients are best managed with conventional angiography.
"Imaging of the internal carotid artery: the dilemma of total versus near total occlusion"S M El-Saden
Dept of Radiology, West Los Angeles Veterans Administration Medical Center, Los Angeles, CA
Radiology 2001(November); 221:301-308
By Ultrasound Review
January 8, 2002
Copyright © 2002 AuntMinnie.com
![Examples of ultrasound findings and techniques. (A) Images in a 39-year-old male patient with a mass in the left thigh. The mass is heterogeneous on the B-mode US image (compared with the patient in D) and showed increased microvascularity (superb microvascular imaging [SMI]) and shear-wave elastography (SWE) values. Undifferentiated pleomorphic sarcoma was diagnosed at biopsy (with pleomorphic rhabdomyosarcoma in surgical specimen). (B) Images in an 18-year-old male patient with a mass in the left leg. The mass is hypoechoic on the B-mode image, with no other findings suggestive of malignancy. The lesion is in contact with the cortex of the tibia, which is slightly irregular. CT revealed a doubtful anteromedial tibial erosion. The microvascular study demonstrated high vascularization, suggestive of malignancy. Periosteal Ewing sarcoma was diagnosed with both histologic and immunohistochemical confirmation. (C) Images in a 69-year-old female patient with a lump growing on the outside of the left leg. Multiple SWE examinations were performed (please note the high values obtained in the measurements, whereas the color map highlights the stiffness relative to adjacent tissues). SMI showed areas of increased vascularization to target for sampling. Undifferentiated spindle cell sarcoma was diagnosed at biopsy, with residual leiomyosarcoma in the surgical specimen after neoadjuvant therapy. (D) Images in a 56-year-old female patient with a mass in the right thigh. The mass is heterogeneous at both B-mode ultrasound (similar to patient A) and MRI (coronal T2-weighted spectral attenuated inversion recovery [SPAIR]; T1-weighted pre-contrast and postcontrast imaging), which even shows uptake after the administration of paramagnetic contrast material, which is traditionally suggestive of malignancy. Low values at SMI and elastography are suggestive of benignity. Spindle cell lipoma was diagnosed at biopsy, with atypical spindle cell lipomatous tumor in the surgical specimen.](https://img.auntminnie.com/mindful/smg/workspaces/default/uploads/2026/08/images-radiol250278fig2.APCFLSvX6p.jpg?auto=format%2Ccompress&fit=crop&h=100&q=70&w=100)
![Examples of ultrasound findings and techniques. (A) Images in a 39-year-old male patient with a mass in the left thigh. The mass is heterogeneous on the B-mode US image (compared with the patient in D) and showed increased microvascularity (superb microvascular imaging [SMI]) and shear-wave elastography (SWE) values. Undifferentiated pleomorphic sarcoma was diagnosed at biopsy (with pleomorphic rhabdomyosarcoma in surgical specimen). (B) Images in an 18-year-old male patient with a mass in the left leg. The mass is hypoechoic on the B-mode image, with no other findings suggestive of malignancy. The lesion is in contact with the cortex of the tibia, which is slightly irregular. CT revealed a doubtful anteromedial tibial erosion. The microvascular study demonstrated high vascularization, suggestive of malignancy. Periosteal Ewing sarcoma was diagnosed with both histologic and immunohistochemical confirmation. (C) Images in a 69-year-old female patient with a lump growing on the outside of the left leg. Multiple SWE examinations were performed (please note the high values obtained in the measurements, whereas the color map highlights the stiffness relative to adjacent tissues). SMI showed areas of increased vascularization to target for sampling. Undifferentiated spindle cell sarcoma was diagnosed at biopsy, with residual leiomyosarcoma in the surgical specimen after neoadjuvant therapy. (D) Images in a 56-year-old female patient with a mass in the right thigh. The mass is heterogeneous at both B-mode ultrasound (similar to patient A) and MRI (coronal T2-weighted spectral attenuated inversion recovery [SPAIR]; T1-weighted pre-contrast and postcontrast imaging), which even shows uptake after the administration of paramagnetic contrast material, which is traditionally suggestive of malignancy. Low values at SMI and elastography are suggestive of benignity. Spindle cell lipoma was diagnosed at biopsy, with atypical spindle cell lipomatous tumor in the surgical specimen.](https://img.auntminnie.com/mindful/smg/workspaces/default/uploads/2026/08/images-radiol250278fig2.APCFLSvX6p.jpg?auto=format%2Ccompress&dpr=2&fit=crop&h=167&q=70&w=250)
