Perspectives in Medicine最新文献

Takayasu arteritis is a panaortitis, more frequent in Japan, South-East Asia India and Mexico, that presents in the 2nd or 3rd decade of life with a non-specific inflammatory phase, then vascular stenosis with ‘pulselessness’ with collateral development. Clinical features include reduced/absent pulses, bruits, hypertension, aortic regurgitation, neurological symptoms from ischemia. While the gold standard for diagnosis is arteriography, magnetic resonance angiography and ultrasonography are now widely used due to their non-invasive nature. Steroids are the cornerstone of medical therapy; cytotoxics may be used for failures. Surgery or angioplasty may be needed for severe vascular stenosis.

Background

Ultrasound perfusion imaging (UPI) with bolus kinetic has been shown to be feasible at bedside for evaluation of perfusion deficits in stroke patients. Recent technical advances allow perfusion imaging with refill kinetics using a low mechanical index.

Methods

We examined 31 acute middle cerebral artery (MCA) stroke patients with transcranial color-coded duplex ultrasound (TCCD) and UPI. The refill of microbubbles was calculated from regions of interest in the ischemic area and the contralateral MCA territory by using the exponential function y = A(1 − e^βt); A = acoustic intensity of the plateau (dB), β = slope (1/s).

Results

We found significantly lower values of β in the ischemic area compared with the contralateral MCA territory (0.75 vs. 1.05 1/s, p < 0.05); particularly in patients with a pathological MCA flow pattern on TCCD (0.61 vs. 1.01, p < 0.01). There was a high interindividual variance without significant difference of the plateau of acoustic intensity (A) in any subgroup of patients.

Discussion

The slope parameter β of refill kinetics is useful for assessing brain perfusion in patients with acute stroke and pathological flow pattern of the ipsilateral MCA. The parameter A, however, seems more dependent from the quality of the temporal bone window.

Carotid intima–media thickness (cIMT) and carotid plaque are ultrasound imaging measures of carotid atherosclerosis and strong predictors of future stroke, myocardial infarction and vascular death. The use of ultrasound measures of cIMT and carotid plaque as a screening tool in clinical practice however have been extremely limited by a lack of recognition of its value by medical communities, health care policy makers and a lack of reimbursement by third-party payers engaged in the delivery of vascular imaging services. This review addresses the role of cIMT and plaque in vascular disease risk prediction. Recent data from large population based studies on reclassification of the vascular risk using carotid ultrasound imaging markers is presented. In addition, the common clinical scenarios for the appropriate use of cIMT in clinical setting are summarized according to the recent study conducted by the Society of the Atherosclerosis Imaging and Prevention in collaboration with the International Atherosclerosis Society. This presentation is intended to provide a practical guide for use of cIMT and plaque to clinicians to promote optimal clinical use of cIMT and to researchers to direct cIMT and plaque research towards investigating environmental and genetic factors of a complex disorder – subclinical atherosclerosis – leading to future genetic discoveries and new anti-atherosclerotic therapies.

Paradoxical embolism is a possible cause of ischemic stroke, particularly in younger patients without any other cause, i.e. cryptogenic stroke, and a patent foramen ovale is the most frequently assumed cause. The contrast transcranial Doppler monitoring mode has a sensitivity that is comparable to contrast transesophageal echocardiography for detection of a right-to-left shunt, however, the contrast transesophageal echocardiography remains the “golden standard” for the detection of a patent foramen ovale. Diagnostic studies that can identify a patent foramen ovale may be considered for prognostic purposes. In most cases, however, it is difficult to establish a firm etiological association and the debate about medical or interventional management is ongoing. Other possible causes of right-to-left shunting leading to cerebral complications like pulmonary arteriovenous malformations have also been noted but are rarely discussed.

Vascular imaging of carotid and vertebral arteries may not be sufficient to evaluate the patients with stroke and other cerebrovascular disorders. Cerebral blood flow measurement can add information to increase the accuracy in diagnosis, assessment, and plan of management in these patients. There are many noninvasive quantitative methods to measure cerebral blood flow including volume flow rate measured by ultrasound. This article addresses mainly the different ultrasound techniques to measure cerebral blood flow. Clinical applications, volume flow rate in normal and abnormal conditions with a case example, and advantage and disadvantage of the ultrasound techniques are also described.

Purpose

To demonstrate the capabilities of 4D ultrasound calf muscle imaging in patients with genetic types of distal myopathies (DMs).

Methods

Three patients with DM were studied: a 58-year-old man with Vocal Cord and Pharyngeal Weakness Distal Myopathy (VCPDM), a 36-year-old woman with Tibial Muscular Dystrophy (TMD) and a 27-year-old woman with Hereditary Inclusion Body Myopathy Type 2 (HIBM2). Their calf muscles were evaluated in rest and during maximal plantar flexion using 3D/4D ultrasound imaging. The results were compared to myosonograms of healthy controls.

Results

All patients had myopathic syndrome due to advanced muscular dystrophy. In comparison to controls abnormal calf muscle architectonics, reduced muscle contractility and a combination of spot-like hypo- and hyperechoic areas were established on 4D ultrasound imaging. The changes were associated with the degree of muscle atrophy, fat and fibrous tissue infiltration.

Conclusions

Four-dimensional myosonology gives additional information for muscle architectonics in patients with genetic types of DM. Further studies are needed to evaluate if the described findings are typical for specific genetic types of myopathy.

The use of ultrasonic methods to evaluate carotid disease differs from country to country. Most popular is the criterion of flow velocity in the stenosis, a criterion influenced by multiple other factors than narrowing of the artery. On the other side angiography does not reliably measure area reduction, responsible for the hemodynamic effect of a stenosis. Therefore correlations of velocity and the degree of stenosis as measured by angiography were never satisfying. In a recent international consensus a multiparametric approach has been proposed aiming to reduce possible errors. This article illustrates some of the possible errors measuring flow velocity with Doppler ultrasound and discusses the background for using multiple criteria. Ultrasound can be used for clinical decision making. This is possible in a clear cut high degree stenosis and in low degree disease. The advantage of Doppler ultrasound is to describe best the hemodynamic consequences of vessel narrowing. This may yield important additional information in combination with other imaging modalities.

Background

Sickle cell disease (SCD) may impair intellectual activity; 25% of SCD patients have a significant cognitive deficit. Our aim was to verify in a cohort of children with HbSS if the presence of silent strokes or altered Time Averaged Mean velocities of Maximum blood flow (TAMM) detected by Transcranial Color Doppler (TCD) Sonography are indicators of impaired intellectual ability.

Methods

Thirty-five consecutive SCD patients (17 males; mean age: 8.6 ± 3.22) were subdivided into two groups according to neuro-psycological deficits. Cognitive function was assessed by WISC III (for the children aged 6–16 years) and WPPSI (for the children aged 4–6 years). All patients underwent a TCD scan of the main intracranial arteries, in order to detect any increase of TAMM velocities (normal <170 cm/s; altered >170 cm/s) and a cerebral MRI to reveal any silent stokes.

Results

According to the neuro-psycological evaluation, 29/35 (82.8%) patients (Group 1) had a “normal” Total Intelligence Quotient (TIQ ≥70), while 6/35 (17.2%) patients (Group 2) were defined intellectually impaired (TIQ <69).

TCD detected altered velocities in 8/35 (22.8%) patients. No significant differences were found in the percentage of altered TAMM velocities between the two groups (Fisher's exact test: p = 0.42).

MRI detected silent ischemic lesions in 14/35 patients (40.0%). No significant differences were found in silent stroke frequencies (Fisher's exact test: p = 0.25) between Group 1 and Group 2.

Conclusion

With the limitations of the study sample, according to our results, altered TAMM values and silent strokes do not seem to be indicators of impaired intellectual ability in SCD patients.

Background

Current protocols stress the importance of short-term diagnosis and treatment in recent TIA or minor stroke. The risk of a recurrent event can be predicted with embolus detection. Studies have shown that the presence of micro-emboli is associated with an increased risk of recurrent events. We explored in our patient population the effect of a zero-tolerance regime for cerebral embolism on outcome.

Methods

Patients with a recent TIA or minor stroke were assigned to a study group or control group. Both groups were treated according to European Stroke guidelines, including prompt start of anti-thrombotic therapy, statins and short-term carotid arteries duplex scanning. The study group was subjected to TCD (Delica 9 series, Shenzen Delicate Electronics Co., LTD., China) embolus detection as soon as possible (EDS, SMT Medical, Wuerzburg, Germany). If emboli were detected, treatment was started immediately to stop cerebral embolization. This was achieved by either an altered drug regimen (clopidogrel) or angioplasty or carotid endarterectomy within one or two days. If carotid intervention was indicated in the control group, it was performed within two weeks, according to European guidelines.

Results

133 patients were enrolled in the study with three months follow-up. 61 patients were subjected to the control group, 72 patients were enrolled in the study group. Recurrent events occurred in 10.2% and 3.0%, respectively (p = 0.145).

Conclusion

The current study shows a non-significant reduction in recurrent events in the study group. Probably sample size in this pilot study was insufficient to detect a significant decline. Nevertheless, the results show that embolus detection is feasible and the zero-tolerance regime may enhance the outcome of TIA and minor stroke patients. The findings support the start of a multicenter randomized trial to assess the clinical value of emboli detection in TIA and stroke care.

Background

Optic Neuritis (ONe) is common in Multiple Sclerosis (MS). The aim of this study was to evaluate the Optic Nerve (ONr) and its vascularisation in MS patients with and without previous ONe and in Healthy Controls (HC).

Methods

We performed high-resolution echo-color ultrasound examination in 50 subjects (29 MS patients and 21 HC). By a suprabulbar approach we measured the ONr diameter at 3 mm from the retinal plane and at another unfixed point. We assessed the flow velocities of Ophthalmic Artery (OA), Central Retinal Artery (CRA) and Central Retinal Vein (CRV) measuring the Peak Systolic Velocity (PSV) and the End Diastolic Velocity (EDV) for the arteries and the Maximal Velocity (MaxV), Minimal Velocity (MinV) and mean Velocity (mV) for the veins. The Pulsatility Index (PI) and the Resistive Index (RI) were also calculated.

Results

No significant variation for OA supply was found as well as no significant variation for CRA supply, while significant higher PI in the CRV of non-ONe MS eyes vs. both HC and ONe MS eyes was measured. We found that ONr diameter was decreased significantly from HC to non-ONe MS eyes and ONe MS eyes.

Conclusions

Ultrasound examination of ONr and its vascularisation is feasible and can demonstrate ON atrophy. The increase of CRV PI in unaffected eyes of MS patients is intriguing and seems not associated to ONr atrophy. Larger studies are needed to confirm these results.