Noninvasive measurement of intracranial pressure via the pulsatility index on transcranial Doppler sonography: Is improvement possible?

PURPOSE: We hypothesized that using hemodynamic variables could improve the prediction of intracranial pressure (ICP) from the middle cerebral artery pulsatility index (PI) measured with transcranial Doppler sonography. METHODS: In this prospective study, 39 patients with traumatic brain injury were routinely examined with transcranial Doppler sonography, and the middle cerebral artery PI was calculated. A multivariate model including hematocrit, mean arterial blood pressure, heart rate, and arterial CO2 pressure (PaCO2 ) was evaluated. RESULTS: Thirty-nine comatose patients (16 women and 23 men; age range 18-73 years; median 44 years) were included, and 234 data pairs (consisting of ICP and corresponding PI values) were analyzed. ICP ranged from -3 mmHg to +52 mmHg, and PI from 0.6 to 2.85. We found a significant but weak correlation between PI and the square root of ICP (R(2) between 0.29 and 0.34, p < 0.0001). A slightly stronger correlation was detected when hemodynamic variables were incorporated (R(2) between 0.37 and 0.43). Of these variables, mean arterial blood pressure had the most significant influence. CONCLUSIONS: In this study, PI was not a sufficiently strong predictor of ICP to be used in clinical practice. Its reliability did not improve even when hemodynamic variables were considered. Therefore, we recommend abandoning the use of PI for the noninvasive measurement of ICP in clinical practice.

Cost-effectiveness of CT angiography and perfusion imaging for delayed cerebral ischemia and vasospasm in aneurysmal subarachnoid hemorrhage.

BACKGROUND AND PURPOSE: Delayed cerebral ischemia and vasospasm are significant complications following SAH leading to cerebral infarction, functional disability, and death. In recent years, CTA and CTP have been used to increase the detection of delayed cerebral ischemia and vasospasm. Our aim was to perform comparative-effectiveness and cost-effectiveness analyses evaluating CTA and CTP for delayed cerebral ischemia and vasospasm in aneurysmal SAH from a health care payer perspective. MATERIALS AND METHODS: We developed a decision model comparing CTA and CTP with transcranial Doppler sonography for detection of vasospasm and delayed cerebral ischemia in SAH. The clinical pathways were based on the "Guidelines for the Management of Aneurysmal Subarachnoid Hemorrhage: A Guideline for Healthcare Professionals from the American Heart Association/American Stroke Association" (2012). Outcome health states represented mortality and morbidity according to functional outcomes. Input probabilities of symptoms and serial test results from CTA and CTP, transcranial Doppler ultrasound, and digital subtraction angiography were directly derived from an SAH cohort by using a multinomial logistic regression model. Expected benefits, measured as quality-adjusted life years, and costs, measured in 2012 US dollars, were calculated for each imaging strategy. Univariable, multivariable, and probabilistic sensitivity analyses were performed to determine the independent and combined effect of input parameter uncertainty. RESULTS: The transcranial Doppler ultrasound strategy yielded 13.62 quality-adjusted life years at a cost of $154,719. The CTA and CTP strategy generated 13.89 quality-adjusted life years at a cost of $147,097, resulting in a gain of 0.27 quality-adjusted life years and cost savings of $7622 over the transcranial Doppler ultrasound strategy. Univariable and multivariable sensitivity analyses indicated that results were robust to plausible input parameter uncertainty. Probabilistic sensitivity analysis results yielded 96.8% of iterations in the right lower quadrant, representing higher benefits and lower costs. CONCLUSIONS: Our model results suggest that CTA and CTP are the preferred imaging strategy in SAH, compared with transcranial Doppler ultrasound, leading to improved clinical outcomes and lower health care costs.

Width of the third ventricle assessed by transcranial sonography can monitor brain atrophy in a time- and cost-effective manner--results from a longitudinal study on 500 subjects.

Ventricular width and its enlargement over time are discussed as promising markers for preclinical brain atrophy. The aim of our study was to define whether brain atrophy can reliably be monitored by transcranial ultrasound (TCS). In a prospective longitudinal trial over 5years, 500 healthy persons were examined by a standardized protocol with TCS in addition to an extensive cognitive testing using the Consortium to Establish a Registry of Alzheimer's Disease - Neuropsychological Testing (CERAD-NP). TCS displayed the third ventricle in 96% of all cases at the follow-up with a high intra-individual reproducibility and excellent inter-rater coefficient (0.992). The mean diameter of the third ventricle in subjects with a cognitive decline was significantly wider (6mm±2) than in subjects with normal cognitive testing results (4.6mm±1.8). We demonstrated that the width of the third ventricle, as a marker of brain atrophy can reliably be monitored by using TCS as a non-invasive, time- and cost-effective method. We provide evidence that the assessed width of the third ventricle can differentiate between subjects with a normal cognitive performance and subjects with a cognitive decline. TCS may be a useful screening tool in the early diagnosis of cognitive decline.

Early diagnosis of Parkinson's disease.

The accuracy of the clinical diagnosis of Parkinson's disease (PD) is still limited. Especially in the early stages, when cardinal symptoms are not conclusive, diagnosis can be delayed as structural neuroimaging methods such as CCT or MRI do not provide characteristic features that allow the diagnosis of this chronic neurodegenerative disorder. Functional neuroimaging using PET and SPECT techniques is helpful in patients with first signs of parkinsonism, but expensive and not broadly available. In this scenario, transcranial sonography (TCS) has proven to be helpful. Up to 90% of PD patients show hyperechogenicity of the substantia nigra (SN) on TCS. Already in the early stages of PD this echofeature is visible, allowing the differentiation of very mildly affected patients with idiopathic PD from healthy persons and from patients with atypical parkinsonism with high sensitivity and specificity. Additionally, specific ultrasound features for some forms of secondary parkinsonism can be detected by TCS, helping in the early identification, for example, of patients with Wilson's disease. Therefore, especially in the early diagnosis, TCS can be recommended as a supplementary tool to facilitate the diagnostic classification of patients with first signs of parkinsonism.

Evaluation of a comprehensive transcranial doppler screening program for children with sickle cell anemia.

BACKGROUND: Although transcranial Doppler ultrasonography (TCD) screening is effective in identifying children with sickle cell anemia (SCA) who are at high risk of stroke, not all children are screened. In 2003, we instituted a comprehensive TCD screening program designed to screen all at-risk children treated at our sickle cell center. PROCEDURE: We evaluated the efficacy of our program by comparing the number of patients screened per year and incidence of first stroke across three periods defined by TCD usage: (1) pre-dating TCD screening, (2) sporadic TCD screening, and (3) comprehensive TCD screening. RESULTS: During Period 2, an average of 52 patients/year were screened. In Period 3, an average of 95 patients/year were screened representing 99% of the at-risk population. Eighteen strokes occurred in Period 1, 22 in Period 2 and three in Period 3. The first stroke incidence was significantly lower in Period 3 compared to Periods 1 and 2 (P = 0.047). Furthermore, of the 25 patients in Periods 2 and 3 who had stroke, only six had received TCD screening (four in Period 2, two in Period 3). These six either declined prophylactic transfusion therapy (n = 2), had co-existing stroke risk factors (n = 2), or did not return for appropriate TCD follow-up (n = 2). Therefore, strokes that occurred were not the result of a failure of TCD screening per se. CONCLUSIONS: It is possible to perform TCD screening of most children with SCA. TCD screening is effective in reducing first stroke incidence in these children.

Transcranial ultrasound diagnosis of intracranial lesions in children with headaches.

The diagnostic value of transcranial ultrasound for intracranial lesions in children with headaches was evaluated. From January 1995 to December 1998, 444 children with headaches for more than 2 weeks visited our Pediatric Neurologic and Neurosurgical Outpatient Clinics. A 2-MHz-sector sonographic transducer was used to perform transcranial ultrasound. Nineteen patients were lost to follow-up. Two patients, both 15 years of age, failed to have a successful examination. Thirteen of the enrolled 423 patients presented with headaches and other symptoms and positive neurologic signs and had positive magnetic resonance imaging findings of intracranial lesions correlating with their transcranial ultrasound findings. Twelve of the remaining 410 children complaining of isolated headache had abnormal transcranial ultrasound findings. Nine of the 12 patients were confirmed to have intracranial lesions by magnetic resonance imaging studies. Among the nine patients, five had brain tumors, two patients had hydrocephalus, one patient had intracerebral hematoma, and one patient had temporal arachnoid cyst. The other three patients were misinterpreted to have a suprasellar lesion by transcranial ultrasound. These three patients and the remaining 398 children were regularly followed for at least 12 months. All revealed no evidence of an intracranial lesion. The sensitivity and specificity of transcranial ultrasound to detect intracranial lesions for children with isolated headaches were 75% and 99.7%, respectively. The average saving from utilizing this technique was $222 U.S. dollars per person. We suggest that transcranial ultrasound study is a reliable, convenient, time-saving, and economic diagnostic tool in detecting intracranial lesions in children with headaches.