Transcranial Ultrasonographic Image Analysis System for Decision Support in Parkinson Disease.

OBJECTIVES: Transcranial ultrasonography (US) is a relatively new neuroimaging modality proposed for early diagnostics of Parkinson disease (PD). The main limitation of transcranial US image-based diagnostics is a high degree of subjectivity caused by low quality of the transcranial images. The article presents a developed image analysis system and evaluates the potential of automated image analysis on transcranial US. METHODS: The system consists of algorithms for the segmentation and assessment of informative brain regions (midbrain and substantia nigra) and a decision support subsystem, which is equipped with 64 classification algorithms. Transcranial US images of 191 participants (118 patients with a clinical PD diagnosis and 73 healthy control participants) were analyzed. RESULTS: The diagnostic sensitivity and specificity achieved by the proposed system were 85% and 75%, respectively. CONCLUSIONS: Digital transcranial US image analysis is challenging, and the application of a such system as the sole instrument for decisions in clinical practice remains inconclusive. However, the proposed system could be used as a supplementary tool for automated assessment of US parameters for decision support in PD diagnostics and to reduce observer variability.

Crucial role of carotid ultrasound for the rapid diagnosis of hyperacute aortic dissection complicated by cerebral infarction: A case report and literature review.

Aortic dissection is a life-threatening rare condition that may virtually present by any organ system dysfunction, the nervous system included. Acute cerebral infarction among multiple other neurological and non-neurological presentations is part of this acute aortic syndrome. Rapid and correct diagnosis is of extreme importance keeping in mind the possibility of thrombolytic treatment if a patient with a suspected ischemic stroke arrives to the Emergency Department within a 4.5-h window after symptom onset. Systemic intravenous thrombolysis in the case of an acute brain infarction due to aortic dissection may lead to fatal outcomes. In this neurological emergency it is important to rule out underlying aortic dissection by choosing appropriately quick and accurate diagnostic tool. We aimed to present a prospective follow-up case, where carotid ultrasound examination was the primary key method that led to a correct diagnosis in hyperacute (<24h) Stanford type A aortic dissection presenting as an acute ischemic stroke, and thereafter with a repeated contrast-enhanced computed tomography and transthoracic echocardiography, helped to monitor topography of intravascular processes and hemodynamic properties during the clinical course of a disease, which influenced treatment decisions. Thus, we reviewed the literature mainly focusing on the various neurological aspects associated with aortic dissection.

Ultrasonographic (TCS) and clinical findings in overlapping phenotype of essential tremor and Parkinson's disease (ET-PD).

BACKGROUND: Essential tremor (ET) and Parkinson's disease (PD) are considered distinct disorders. The aim of the study was to look for a link or any distinguishing features by transcranial sonography (TCS), together with the clinical examination findings in a group of patients with overlapping phenotype of ET and PD (ET-PD). METHODS: A prospective observational case-control study was carried out from the 3rd January 2011 until 30th January 2013 at the Hospital of Lithuanian University of Health Sciences. The final study group consisted of 15 patients with ET-PD, 116 patients with ET-only and 141 patients with PD-only. The control group included 101 subjects. Clinical diagnosis was of a diagnostic standard. RESULTS: The main ultrasonographic findings in the ET-PD group were similar to those of the PD-only: hyperechogenicity of the substantia nigra (66.7%, p < 0.001) and nuclei raphe interruptions/absence (38.5%, p < 0.001). The single distinguishing TCS finding in ET-PD group was a lentiform nucleus hyperechogenicity (26.7%), however this was only significant when compared to controls (p = 0.006). An asymmetrical onset of symptoms (73.3%) in ET-PD group was characteristic to PD-only. The ET-PD patients had the longest disease duration (median 6 years, p < 0.001), the most frequent rate of positive family history (53.3%, p = 0.005), rather low prevalence of cogwheel rigidity (26.7%, p < 0.001), and higher mean Hoehn & Yahr scores compared to PD-only (2.6 ± 0.8 vs. 1.8 ± 0.8, p = 0.012). CONCLUSIONS: The main TCS findings of the present study in patients with overlapping ET-PD phenotype were similar to the PD-only group. The highest positive family history rate among ET-PD patients indicates a strong hereditary predisposition and needs genetic underpinnings. Some ET patients, who look like they may be developing co-morbid PD clinically, may have an alternative diagnosis for Parkinsonism, which could be delineated by TCS examination.

Specificity of transcranial sonography in parkinson spectrum disorders in comparison to degenerative cognitive syndromes.

BACKGROUND: Hyperechogenicity of the substantia nigra (SN+), detected by transcranial sonography (TCS), was reported as a characteristic finding in Parkinson's disease (PD), with high diagnostic accuracy values, when compared mainly to healthy controls or essential tremor (ET) group. However, some data is accumulating that the SN + could be detected in other neurodegenerative and even in non-neurodegenerative disorders too. Our aim was to estimate the diagnostic accuracy of TCS, mainly focusing on the specificity point, when applied to a range of the parkinsonian disorders, and comparing to the degenerative cognitive syndromes. METHODS: A prospective study was carried out at the Hospital of Lithuanian University of Health Sciences from January until September 2011. Initially, a TCS and clinical examination were performed on 258 patients and 76 controls. The General Electric Voluson 730 Expert ultrasound system was used. There were 12.8% of cases excluded with insufficient temporal bones, and 4.3% excluded with an unclear diagnosis. The studied sample consisted of the groups: PD (n = 71, 33.2%), ET (n = 58, 27.1%), PD and ET (n = 10, 4.7%), atypical parkinsonian syndromes (APS) (n = 3, 1.4%), hereditary neurodegenerative parkinsonism (HDP) (n = 3, 1.4%), secondary parkinsonism (SP) (n = 23, 10.8%), mild cognitive impairment (MCI) (n = 33, 15.4%), dementia (n = 13, 6.1%), and control (n = 71). RESULTS: There were 80.3% of PD patients at stages 1 & 2 according to Hoehn and Yahr. At the cut-off value of 0.20 cm² of the SN+, the sensitivity for PD was 94.3% and the specificity - 63.3% (ROC analysis, AUC 0.891), in comparison to the rest of the cohort. At the cut-off value of 0.26 cm², the sensitivity was 90% and the specificity 82.4%.The estimations for the lowest specificity for PD, in comparison to the latter subgroups (at the cut-off values of 0.20 cm² and 0.26 cm², respectively) were: 0% and 33.3% to APS, 33.3% and 66.7% to HDP, 34.8% and 69.6% to SP, 55.2% and 82.8% to ET, 75% and 91.7% to dementia. CONCLUSIONS: The high sensitivity of the test could be employed as a valuable screening tool. But TCS is more useful as a supplementary diagnostic method, due to the specificity values not being comprehensive.

Diagnostic value of conventional visual evoked potentials applied to patients with multiple sclerosis.

OBJECTIVE: The aim of this study was to determine the sensitivity and specificity of this classical technique employed at the Hospital of Lithuanian University of Health Sciences for the patients with multiple sclerosis and to assess its possible correlations with affected neurological systems. MATERIAL AND METHODS: Pattern shift visual evoked potentials were recorded in 63 patients with multiple sclerosis, 17 (27%) of whom had a history of optic neuritis, and in 63 control patients with other neurological diseases. The latencies and amplitudes of P100 were measured. In total, 126 patients were referred to the inpatient department of neurology for differential diagnosis of demyelinating disorders between January and December of 2007. RESULTS: Abnormalities of visual evoked potentials were observed by 73% more frequently in patients with multiple sclerosis than in control patients (α=0.05, ß<0.01). The combined monocular/interocular test showed a specificity of 90.5% and a sensitivity of 82.5%. The probability of an affection of the pyramidal system was 5 times greater (95% CI, 2.2-11.0; P<0.01) and the probability of the optic pathways involvement was 4.8 times greater (95% CI, 1.9-11.9; P<0.01) in patients with multiple sclerosis than in controls. CONCLUSION: Conventional visual evoked potentials must be reappraised in light of their diagnostic value in multiple sclerosis given their high diagnostic efficiency, relatively easy, short, and cheap implementation, and easy availability in everyday clinical practice.

Computer-Aided Segmentation of the Mid-Brain in Trans-Cranial Ultrasound Images.

This paper presents a novel and rapid method developed for semi-automated segmentation of the mid-brain region in B-mode trans-cranial ultrasound (TCS) images. TCS is a relatively new neuroimaging tool having promising application in early diagnosis of Parkinson's disease. The quality of TCS images is much lower compared with the ultrasound images obtained during scanning of the soft tissues; the structures of interest in TCS are difficult to extract and to evaluate. The combination of an experience-based statistical shape model and intensity-amplitude invariant edge detector was proposed for the extraction of fuzzy boundaries of the mid-brain in TCS images. A statistical shape model was constructed using 90 manual delineations of the mid-brain region made by professional neurosonographer. Local phase-based edge detection strategy was applied for determination of plausible mid-brain boundary points used for statistical shape fitting. The proposed method was tested on other 40 clinical TCS images evaluated by two experts. The obtained averaged results of segmentation revealed that the differences between manual and automated measurements are statistically insignificant (p > 0.05).

Automated segmentation of transcranial sonographic images in the diagnostics of Parkinson's disease.

Images captured during routine clinical transcranial sonography (TCS) examination are of a low resolution, so can be confusing for diagnostic evaluations. Manual segmentation of brain structures (areas of the midbrain and substantia nigra (SN)) that are of special interest cause inter-observer and intra-observer variability, thus restricting the reliability of Parkinson disease (PD) diagnostics. This paper presents a new technique for automated segmentation applicable to low resolution sonographic images, and particularly to brain structures related to PD. The segmentation was performed by a modified shape-based active contour (AC) segmentation algorithm. In order to suppress the speckle noise and to improve the AC segmentation, a pre-processing technique based on the averaging of adjusted spatially varying TCS images is proposed. The latter technique was tested on clinical TCS images. The results of the automated segmentation were compared with the manual markings. Two experts on the 40TCS images performed these markings. The comparison showed that an automated method is effective when segmentation of the midbrain is performed (averaged overlap between regions obtained automatically and outlined manually was 73.10±7.45%). The results of the segmentation of the SN area showed that a sufficiently correct contour of this area could also be obtained, but the accuracy of the segmentation is related to the image quality. It should be emphasised that the main difficulty in evaluating the accuracy of automated segmentation of the SN was the indefinite "gold standard" (variation between the measurements of two experts with different experience was found). And, therefore, the diagnostic reliability of the proposed technique was inconclusive.