Substantia nigra hyperechogenicity in essential tremor and Parkinson's disease: a longitudinal study.

BACKGROUND AND PURPOSE: Essential tremor (ET) and Parkinson's disease (PD) sometimes overlap in their clinical expression with ET preceding PD onset, often leading to misdiagnosis. Transcranial sonography (TCS) has been shown to be a valid and non-invasive diagnostic tool to identify early idiopathic PD and to differentiate it from ET. The purpose of this study was to investigate the relevance of substantia nigra hyperechogenicity in patients with ET. METHODS: A total of 138 patients (79 with PD, 59 with ET) and 50 matched controls underwent TCS examination at baseline. All patients were followed in a 3-year longitudinal assessment. RESULTS: A total of 10 subjects were excluded from the analysis due to the bilateral absence of a temporal acoustic window. During the follow-up period, 11 of the patients with ET developed new-onset parkinsonian features, without fulfilling criteria for PD diagnosis (ET+). Nine patients developed clinical features meeting diagnostic criteria for probable PD (ET-PD). Patients with ET- did not develop parkinsonian features. For each group, the maximum size of the substantia nigra hyperechogenicity was as follows: 5.62 ± 5.40 mm2 in the control group, 19.02 ± 14.27 mm2 in patients with PD, 9.15 ± 11.26 mm2 in patients with ET-, 20.05 ± 13.78 mm2 in patients with ET+ and 20.13 ± 13.51 mm2 in patients with ET-PD. ET-PD maximum values were significantly different from controls. Maximum values in patients with ET+ were different from both controls and patients with ET-. CONCLUSION: Substantia nigra hyperechogenicity in ET seems to represent a risk marker for developing early parkinsonian symptoms or signs in the 3 years following TCS assessment.

CT angiography versus colour-Doppler US in acute dissection of the vertebral artery.

PURPOSE: Conventional digital subtraction angiography (DSA) still represents the criterion standard for the diagnosis of vertebral artery dissection (VAD), but the main drawbacks of this technique include invasiveness, patient discomfort and risk of complications. We evaluated the potential of multidetector computed tomography angiography (CTA) as a noninvasive tool providing high-resolution images of the arterial lumen and wall by comparing the diagnostic accuracy of CTA and colour-Doppler ultrasonography (CDUS) in detecting acute VAD. MATERIALS AND METHODS: We retrospectively reviewed 15 cases of VAD in 15 patients (five men and ten women, age range 28-58 years) who came to our attention between August 2001 and September 2005. The diagnosis was made on the basis of appropriate clinical presentation, absence of atherosclerotic disease in the cerebrovascular circulation and evidence of distinctive CT features, which were subsequently confirmed by conventional angiography used as reference standard. All patients with a clinical suspicion of VAD underwent CDUS of the neck vessels prior to CTA. Accuracy, sensitivity and specificity of CDUS and CTA were expressed as percentages of agreement with the reference angiographic procedure. Interreader concordance for detection of VAD by CTA was calculated with the Cohen K value. RESULTS: The CDUS examinations revealed ten out of 15 VAD, with a sensitivity of 66%, a specificity of 60%, a positive predictive value of 55.5% and a negative predictive value of 70.5%. In five cases, CDUS revealed nonspecific wall and flow alterations; in eight patients, high resistance obstructive flow; and in two patients, intimal flap with demonstration of the true and false lumen. CTA enabled the correct identification of all 15 VAD. The reported sensitivity, specificity, positive predictive value and negative predictive value were 100%, 95%, 93.7% and 100%, respectively. With regard to localisation of VAD, CTA showed 100% correlation with DSA. The differences in CTA and CDUS sensitivity (100% vs 66%), specificity (95% vs 60%), and overall diagnostic accuracy (97% vs 62.8%), assessed by cross tabulations and compared by using the McNemar's two-sided test, were significant (p<0.05). CONCLUSIONS: Multidetector CTA is a sensitive technique for the diagnosis of VAD. Used as a complement to unenhanced brain CT, it has the advantage of being readily available and easy to perform.

Multimodal use of computed tomography in early acute stroke, part 2.

Computed tomography (CT) scan remains the most widely technique in the cerebrovascular emergency, as it is largely available, minimally invasive, fast, cheap and reliable. Noncontrast enhanced CT (NeCT) imaging can show early signs of infarction in ischemic stroke; however, it could not show if the ischemic tissue is irreversibly damaged. CT perfusion (CTP) imaging has been shown to predict stroke location and size and can provide information about ischemic cerebral parenchyma not definitively compromised. CT angiography (CTA) could highlight stenosis or occlusion both in intracranial and extracranial vessels. By combining NeCT, CTP, and CTA the entire cerebrovascular axis can be imaged during acute stroke. Currently, the term "multimodal CT" indicates the combined use of these three techniques in order to obtain a complete picture of the extension of ischemic damage in acute stroke patients.

Stroke related to carotid artery dissection in a young patient with Takayasu arteritis, systemic lupus erythematosus and antiphospholipid antibody syndrome.

Autoimmune diseases are rarely the cause of stroke even in the young age group in association with cervical artery dissection and collagen vascular diseases. Takayasu arteritis is a chronic, idiopathic, inflammatory disease that primarily affects large vessels, such as the aorta and its main branches. Takayasu arteritis rarely coexists with systemic lupus erythematosus, and only few cases have been reported in association with the presence of antiphospholipid antibodies. We describe a young patient with right internal carotid artery dissection and subsequent stroke who presented with all three syndromes. Although this patient met the diagnostic criteria for each syndrome, systemic lupus erythematosus, Takayasu arteritis and the antiphospholipid antibody syndrome, it remains unlikely that the three disorders are not related. We suggest a single disimmune disorder may have led to carotid artery dissection.

Mild hyperhomocyst(e)inemia: a possible risk factor for cervical artery dissection.

BACKGROUND AND PURPOSE: The pathogenesis of cervical artery dissection (CAD) remains unknown in most cases. Hyperhomocyst(e)inemia [hyperH(e)], an independent risk factor for cerebrovascular disease, induces damage in endothelial cells in animal cell culture. Consecutive patients with CAD and age-matched control subjects have been studied by serum levels of homocyst(e)ine and the genotype of 5,10-methylenetetrahydrofolate reductase (MTHFR). METHODS: Twenty-six patients with CAD, admitted to our Stroke Unit (15 men and 11 women; 16 vertebral arteries, 10 internal carotid arteries), were compared with age-matched control subjects. All patients underwent duplex ultrasound, MR angiography, and/or conventional angiography. RESULTS: Mean plasma homocyst(e)ine level was 17.88 micromol/L (range 5.95 to 40.0 micromol/L) for patients with CAD and 6.0+/-0.99 micromol/L for controls (P:<0.001). The genetic analysis for the thermolabile form of MTHFR in CAD patients showed heterozygosity in 54% and homozygosity in 27%; comparable figures for controls were 40% (P:=0.4) and 10% (P:=0.1), respectively. CONCLUSIONS: Mild hyperH(e) might represent a risk factor for cervical artery dissection. The MTHFR mutation is not significantly associated with CAD. An interaction between different genetic and environmental factors probably takes place in the cascade of pathogenetic events leading to arterial wall damage.