Non-Invasive Cerebral Hemodynamics, Vasospasm Surveillance & Neonatal Neurosonography
Neuro-Ultrasound, Transcranial Doppler (TCD) & Carotid Duplex
Clinical Overview & Pathophysiology
Clinical Classifications & Pathological Subtypes
- Transcranial Doppler (TCD) & TCD Monitoring: Non-invasive pulsed 2 MHz Doppler measuring mean flow velocity (MFV) and pulsatility index (PI) in the Middle, Anterior, and Posterior Cerebral Arteries and Basilar Artery.
- Carotid & Vertebral Duplex Doppler Ultrasound: High-resolution B-mode imaging combined with color and spectral Doppler quantifying internal carotid artery stenosis, plaque ulceration, and vertebral flow reversal.
- Intraoperative Neurosurgical Ultrasound (iUS): Specialized micro-convex surgical transducers placed directly onto the exposed dura or brain cortex during tumor resection to compensate for brain shift and verify complete removal.
- Neonatal Cranial Neurosonography: Bedside imaging through the anterior fontanelle assessing ventricular dilation (hydrocephalus), periventricular leukomalacia (PVL), and germinal matrix hemorrhage.
- Optic Nerve Sheath Diameter (ONSD) Ultrasound: Bedside ocular ultrasound measuring the retrobulbar optic nerve sheath diameter as a non-invasive surrogate metric of raised intracranial pressure (ICP).
Key Symptoms & Clinical Presentation
!Emergency Red Flags & Immediate Surgical Indications
TCD middle cerebral artery mean flow velocity exceeding 200 cm/s with a Lindegaard Ratio > 6 (indicating severe critical cerebral vasospasm requiring emergent hemodynamic augmentation or intra-arterial spasmolysis) or unstable, ulcerated, hypoechoic carotid plaques with > 80% stenosis. Immediate neurosurgical intervention is vital.
Diagnostic & Neuro-Evaluation Workflow
Multi-Frequency Digital Color Duplex Ultrasound Systems
Equipped with dedicated linear vascular probes (5-12 MHz) and phased-array low-frequency sector transducers (1-3 MHz).
Transcranial Power Doppler with M-Mode
Simultaneous depth-gate recording tracing blood flow spectra across multiple intracranial vessel depths simultaneously.
Contrast-Enhanced Ultrasound (CEUS)
Microbubble contrast agent infusion for high-resolution microvascular perfusion imaging of brain tumors and plaque neovascularization.
Non-Invasive Intracranial Compliance Profiling
Continuous waveform analysis calculating resistivity index (RI) and pulsatility index (PI) to assess cerebral microvascular resistance.
Advanced Treatments & Procedures by Dr. Ashok Kumar
Vasospasm-Guided Hyperdynamic Therapy
Guiding induced hypertension, euvolemia, and intra-arterial nimodipine infusions in the Neuro-ICU based on daily TCD velocity metrics.
Carotid Endarterectomy (CEA) Selection
Identifying symptomatic and asymptomatic patients meeting NASCET criteria for microsurgical carotid plaque removal to prevent catastrophic strokes.
Real-Time Resection Guidance in Brain Surgery
Using iUS to visualize deep-seated tumor margins, identify the ventricle, and confirm empty tumor resection cavities before closing the dura.
Fontanelle Tap & Ventricular Access Guidance
Real-time ultrasound guidance for bedside reservoir needle placement or ventricular puncture in neonates.
Post-Operative Recovery & Long-Term Prognosis
Neuro-ultrasound procedures are completely safe, non-invasive, radiation-free, and pain-free, requiring zero needles or sedation. Patients can undergo repeated scans at the bedside in the ICU or outpatient clinic without any recovery time.
