Bao-Show Hwang

Ultrasonographic Study and Long-term Follow-up of Takayasu's Arteritis

BACKGROUND AND PURPOSE Takayasus arteritis is an inflammatory vasculopathy involving the aorta and its major branches. Little information is available on the natural history and temporal profile of changes in the carotid vessels, the major vessels involved in Takayasus arteritis. Duplex ultrasonography may provide a reliable and efficient tool for the characterization and follow-up of the brachiocephalic vascular changes in Takayasus arteritis. METHODS Sixteen female patients fulfilling the clinical diagnostic criteria for Takayasus arteritis were studied. Mean age at onset was 23.6 years (SD = 6.0), and mean duration of follow-up was 17.1 years (SD = 11.9). The clinical features were analyzed. Only one patient had had a stroke. They had undergone at least one duplex scanning examination to evaluate the brachiocephalic vessels, including the extracranial carotid, vertebral, and subclavian arteries. Six patients underwent sequential duplex examination and long-term clinical follow-up. RESULTS All the studied patients had subclavian artery involvement, and 11 (69%) had common carotid artery involvement. The percentage of bilateral concomitant involvement was 100% in the common carotid artery and 33% in the subclavian artery. Homogeneous circumferential intima-media thickening was commonly seen in stenotic common carotid arteries (89%). Four patients had internal carotid artery involvement (all on the left side). In the serial duplex follow-up study, 2 of 6 patients had progressive vascular stenosis with concentric thickening, rather than longitudinal spreading, in the bilateral common carotid arteries. Left-side lesions were more prominent. Most were clinically stationary, despite severe stenosis or occlusion of the common carotid arteries. CONCLUSIONS The characteristic vascular lesions and progression changes in Takayasus arteritis detected by duplex ultrasonography are quite different from those seen in ordinary atherosclerosis. Homogeneous circumferential intima-media thickening of the common carotid arteries is a highly specific ultrasonographic finding in patients with Takayasus arteritis, particularly young women. Sequential duplex scanning showed vascular progression to be unpredictable and unrelated to medication in our patients. Further clinical investigations of vascular progression are warranted, and duplex scanning may provide a simple, safe, and accurate long-term means of follow-up.

Extracranial carotid atherosclerosis and vascular risk factors in different types of ischemic stroke in Taiwan.

The clinical patterns of stroke and the angiographic distribution of cerebral atherosclerosis in Chinese people are different from those in whites. Studies relating carotid atherosclerosis and vascular risk factors to various types of stroke in Chinese people are lacking. Methods Based on clinical information, we separated 367 stroke patients living in Taiwan into four subgroups: cortical infarction (CI), subcortical infarction (SCI), vertebrobasilar artery infarction (VBAI), and cardioembolic infarction (CEI). We assessed the extent and severity of extracranial carotid artery atherosclerosis in different types of ischemic stroke using duplex ultrasonography. Vascular risk factors and carotid atherosclerosis were then correlated with each subgroup of ischemic stroke. Results Our data revealed that 32% of the CI subgroup, 3% of the SCI subgroup, 7% of the VBAI subgroup, and 21% of the CEI subgroup possessed severe carotid stenosis (≥50% stenosis or occlusion). The extent of atherosclerosis of extracranial carotid arteries, measured by plaque score, was also more severe in the CI subgroup than in the other subgroups. Diabetes mellitus was more frequent in the CI subgroup. Cardiomegaly and left ventricular hypertrophy were more commonly seen in the CEI subgroup. The VBAI subgroup was younger than the other subgroups. There were no differences in hypertension, prior stroke, alcohol intake, or serum levels of glucose, uric acid, hematocrit, lipids, and lipoproteins among the subgroups. Conclusions Of the Chinese patients living in Taiwan, the extent and severity of extracranial carotid artery atherosclerosis were more prominent in patients with CI than in patients with other types of ischemic stroke. In Chinese patients with CI, severe carotid stenosis is not uncommon; in Chinese patients with SCI, however, the frequency of carotid stenosis is quite low.

Carotid and transcranial color-coded duplex sonography in different types of carotid-cavernous fistula.

BACKGROUND AND PURPOSE Patients with carotid-cavernous fistula (CCF) may undergo direct or indirect shunting. Ultrasonography has value that is complementary to angiography in the assessment and follow-up of these patients. The aim of this study was to characterize findings provided by carotid duplex sonography (CDS) and transcranial color-coded duplex sonography (TCCD) in patients with different types of CCF. METHODS CDS and TCCD were independently performed by technologists and neurologists. Digital subtraction or MR angiography was interpreted by a neuroradiologist. Ultrasonographic studies were categorized into 4 types: I, direct shunting only; II, direct shunting with a carotid aneurysm; III, indirect shunting only; and IV, mixed (direct and indirect) shunting. In addition to carotid and intracranial flow velocities, volume, and pulsatility, other direct and indirect ultrasound signs of shunting were evaluated. The direct sign of CCF was a mosaic flash detected by TCCD. Alteration of hemodynamic parameters on CDS and demonstration of draining veins with the use of TCCD were considered indirect signs. RESULTS Fifteen patients (8 men, 7 women) were included in the study. According to angiographic results, patients in ultrasonographic classification types I (n=7) and II (n=3) corresponded to type A of Barrows classification. Patients with type III (n=8) were Barrows type C. Type IV (n=1) had a combination of Barrows types A and C. On ultrasound, both direct and indirect signs were seen in types I, II, and IV CCF. The presence of a 2-colored oval mass divided by a zone of separation without turbulence differentiated type I from type II CCF. All patients with type III CCF had indirect signs, and only 1 patient had direct signs on TCCD. Abnormal TCCD findings were most commonly seen through the transorbital window (100%), followed by the transtemporal window (63%) and transforaminal window (40%). CONCLUSIONS If only indirect ultrasonographic signs of CCF are present, TCCD can be used to predict an indirect CCF type on the basis of the origin of the fistula. With direct communication between carotid artery and cavernous sinus, both direct and indirect ultrasonographic signs can be found. The combination of CDS/TCCD may provide a noninvasive and reliable way to classify patients with CCF.

Imaging in the diagnosis and follow-up evaluation of vertebral artery dissection.

The purpose of this report is to discuss the value of ultrasonographic examination in the diagnosis and follow‐up evaluation of vertebral artery dissection. We collected data on 8 patients with 11 pathologic vessels: 9 were affected intracranially and 6 were affected extracranially. Four vessels were affected in both intracranial and extracranial segments. Extracranial color‐flow duplex sonography could detect abnormalities in every extracranial vertebral artery dissection. Most abnormal findings were non‐specific, including severely reduced flow, absence of flow, and absence of diastolic flow. A specific finding (intramural hematoma) was noted in one artery. Abnormal transcranial color‐coded sonographic findings included absence of flow, reduced velocity and reversed flow direction. Three intracranial dissecting arteries showed normal findings on transcranial color‐coded sonography. Ultrasonographic follow‐up study revealed evidence of improvement; this was noted almost exclusively in the extracranial segments of the vertebral artery but infrequently in the intracranial segment. Extracranial color‐flow duplex sonography is sensitive in the detection of extracranial vertebral artery dissection, both in initial diagnosis and in follow‐up evaluation.

Subclavian steal phenomenon: a correlation between duplex sonographic and angiographic findings

SummaryCorrelation of duplex sonography, angiography of the vertebral artery, and the degree of subclavian or innominate stenosis was carried out in ten patients with the subclavian steal phenomenon. Four successive stages of Doppler waveform were identified by duplex sonography. Three angiographic patterns of decreasing severity, permanent reversal, to-and-fro motion and delayed opacification, were found. Permanent reversal angiograms corresponded to complete reversal or late transient Doppler waveforms. To-and-fro motion and delayed opacification angiograms did not necessarily have a corresponding Doppler pattern. The different stages of subclavian steal phenomenon on duplex sonography correlated significantly with the degree of subclavian or innominate stenosis. Stenosis of at least 60% was found to produce abnormal vertebral artery Doppler sonography, except in one patient. Duplex sonography is considered to be a sensitive and convenient method for detecting abnormal vertebral artery haemodynamics and the subclavian steal phenomenon, but some other factors may be important in producing the Doppler waveforms.

Noninvasive hemodynamic classification of carotid-cavernous sinus fistulas by duplex carotid sonography

The hemodynamic classification of the CCF has important implications for prognosis and therapy, but satisfactory criteria for such a differentiation are still lacking. We studied the application of extracranial duplex sonography in 14 cases of CCF with emphasis on the hemodynamic parameters of the RI and flow volume and made a correlation with the angiographic findings. We conclude with proposed duplex sonographic criteria for hemodynamic classification: (1) small RI with increased flow volume in the ICA: direct ICA‐cavernous sinus fistulas (type A); (2) normal RI and flow volume in the ICA and ECA: dural branch of ICA‐cavernous sinus fistulas (type B); (3) small RI with or without increased flow volume in the ECA: dural branch of ECA‐cavernous sinus fistulas (type C) or dural branches of ICA‐ and ECA‐cavernous sinus fistulas (type D). Application for assessment of the therapeutic effectiveness was also demonstrated.

Transcranial Color-Coded Sonography for the Detection of Middle Cerebral Artery Stenosis

The purpose of this study was to validate the accuracy and criteria of transcranial color‐coded sonography (TCCS) in detecting severe middle cerebral artery (MCA) stenosis.

The relationships among serum glucose, albumin concentrations and carotid atherosclerosis in men with spinal cord injury

Limited information is available that examines the interrelationships between glucose tolerance, serum albumin, subclinical inflammation, and carotid atherosclerosis (CA) in patients with spinal cord injury (SCI). We prospectively recruited 110 male patients with traumatic SCI, 57 with SCI at thoracic level 6 or above (SCI-T6) and 53 with SCI at T7 or below (SCI-T7), and 62 age-matched able-bodied controls from the National Taiwan University Hospital. The associations among glucose levels after oral glucose tolerance tests (OGTT), serum albumin, high-sensitivity C-reactive protein (hs-CRP), and CA in terms of the extracranial carotid artery (ECCA) plaque score and common carotid artery (CCA) intima-media thickness (IMT) were examined. Results showed significantly higher post-challenge glucose levels and carotid plaque scores and lower serum albumin in the SCI-T6 patients. In addition, serum albumin was negatively associated with CA and post-challenge glucose levels. The higher post-challenge glucose levels at 120min (Glu120) were associated with higher serum hs-CRP levels and lower serum albumin levels. In addition, lower serum albumin levels were associated with a thicker CCA IMT and a higher prevalence of ECCA plaque. Mixed models revealed that body mass index, age, LDL-cholesterol, Glu120, homeostasis model assessment for insulin resistance (HOMA-IR), lower serum albumin and smoking habits were positively associated with CCA IMT. Age, HOMA-IR, LDL-cholesterol, and lower serum albumin were identified as the important factors for the presence of carotid plaque by multiple linear regression analyses. In conclusion, post-challenge hyperglycemia and serum albumin levels are important indicators of CV health in men with SCI.

Color Doppler sonographic study of an iatrogenic fistula between the common carotid artery and internal jugular vein.

Percutaneous catheterization of the central veins is a well-accepted procedure in patient care. Various complications, including pneumothorax, brachial plexus inju~ venous thrombosis, AVF, and subcutaneous hematoma have been reported after cannulation of the central veins. l..2 Of these, an AVF is relatively uncommon but potentially serious. The use of color Doppler sonography could be a convenient way of assessing this vascular complication; however, the reports about this advanced technology are few.J-5 We describe a uremic patient who had developed an AVF between the CCA and internal jugular vein after attempts to insert a dialysis catheter via the internal jugular vein. A thorough

Reverse Jugular Flow in a Case of Thrombosis of the Brachiocephalic Vein with an Artificial Arteriovenous Fistula A Case Report

Thrombosis of the thoracic inlet veins following placement of a central venous catheter is a well-known complication, and several findings have been reported by color Doppler sonography. However, reverse jugular flow resulting from this complication is rarely mentioned and should be differentiated from another complication of iatrogenic arteri ovenous fistula between neck vessels. The authors here describe a uremic patient with an artificial arteriovenous fistula in the forearm complicated with thrombosis of the ipsilat eral brachiocephalic vein. Factors permitting the differential diagnosis by color Doppler sonography and clinical conditions are proposed.