Biomedical subjects

J Lazareff

Publications and source records attributed to J Lazareff.

3 recordsLinked to original sources

PubMed2001

Perioperative transcranial Doppler US to evaluate intracranial compliance in young children undergoing craniosynostosis repair surgery.

PURPOSE: To determine whether measurements with transcranial Doppler ultrasonography (US) of resistive indexes (RIs) of basal cerebral arteries with pressure provocation can be used to identify infants and children with craniosynostosis who have abnormal intracranial compliance and to study the effects of surgery on compliance. MATERIALS AND METHODS: Transcranial Doppler US was performed through the temporal squama, fontanels, and existing skull defects prior to and immediately following cranioplasty. Twenty-four studies were performed in six patients with multisuture synostosis, and 61 studies were performed in 26 patients with single-suture synostosis. Study findings were compared with those of 23 control subjects and were characterized as normal or abnormal on the basis of age-specific normal criteria for RI. RESULTS: In multisuture synostosis, results of six of the nine preoperative transcranial Doppler US studies were abnormal. During postoperative follow-up, three recurrences requiring reoperation occurred, one of which was detected with abnormal transcranial Doppler US findings. In single-suture synostosis, results of seven of the 26 preoperative transcranial Doppler US studies were abnormal, and all occurred in young infants with sagittal and unicoronal synostosis. Immediate effects of surgery were variable. All patients with sagittal synostosis had a significant immediate postoperative increase in RI, which normalized during postoperative follow-up. There was no significant difference in RI between patients with successfully treated craniosynostosis and control subjects. CONCLUSION: Transcranial Doppler US can be used to identify patients with craniosynostosis with decreased intracranial compliance, and it is a suitable noninvasive test to monitor the effects of surgery on compliance.

Child, Preschool↗

PubMed2000

Relationships between choline magnetic resonance spectroscopy, apparent diffusion coefficient and quantitative histopathology in human glioma.

This study sought to correlate quantitative presurgical proton magnetic resonance spectroscopic imaging (1H-MRSI) and diffusion imaging (DI) results with quantitative histopathological features of resected glioma tissue. The primary hypotheses were (1) glioma choline signal correlates with cell density, (2) glioma apparent diffusion coefficient (ADC) correlates inversely with cell density, (3) glioma choline signal correlates with cell proliferative index. Eighteen adult glioma patients were preoperatively imaged with 1H-MRSI and DI as part of clinically-indicated MRI evaluations. Cell density and proliferative index readings were made on surgical specimens obtained at surgery performed within 12 days of the radiologic scans. The resected tissue location was identified by comparing preoperative and postoperative MRI. The tumor to contralateral normalized choline signal ratio (nCho) and the ADC from resected tumor regions were measured from the preoperative imaging data. Counts of nuclei per high power field in 5-10 fields provided a quantitative measure of cell density. MIB-1 immunohistochemistry provided an index of the proportion of proliferating cells. There was a statistically significant inverse linear correlation between glioma ADC and cell density. There was also a statistically significant linear correlation between the glioma nCho and the cell density. The nCho measure did not significantly correlate with proliferative index. The results indicate that both ADC and spectroscopic choline measures are related to glioma cell density. Therefore they may prove useful for differentiating dense cellular neoplastic lesions from those that contain large proportions of acellular necrotic space.

Adult↗

PubMed1998

Transcranial Doppler ultrasonography to evaluate need for cerebrospinal fluid drainage in hydrocephalic children.

The aim of this study was to determine whether the resistive index in the anterior cerebral artery, as measured by transcranial Doppler ultrasonography without and with pressure provocation, predicts the need for cerebrospinal fluid drainage in hydrocephalic children. Both without and with pressure provocation, the resistive index was significantly higher (P > 0.05) in patients with raised intracranial pressure compared with control group patients and dropped significantly after drainage. With receiver operating characteristic analysis, the optimal cutoff point between normal and abnormal resistive index values was determined at 0.71 without pressure provocation and at 0.90 with pressure provocation. The addition of the pressure provocation test improved accuracy from 81 to 91%, mainly by improving specificity. In conclusion, transcranial Doppler ultrasonography with pressure provocation accurately identifies hydrocephalic children who require cerebrospinal fluid drainage procedures.

Cerebrospinal Fluid Shunts↗