Real-Time 2D Ultrasound Guided Frameless Biopsy of a Multifocal Glioma: Improving Accuracy and Diagnostic Yield
Correspondence Address: Source of Support: None, Conflict of Interest: None DOI: 10.4103/0028-3886.333481
Source of Support: None, Conflict of Interest: None
Keywords: 2D ultrasound, frameless brain biopsy, intraoperative ultrasound, ultrasound-guided biopsy
In the current era of immunohistochemical characterization of tumors in neuropathology and targeted therapies, tissue diagnosis through biopsy or surgical resection is essential. There are two techniques for tissue diagnosis: frame-based image-guided and frameless navigation-guided stereotactic biopsy. Both are well established as diagnostic procedures. Ultrasound has proven to be an advantageous intraoperative imaging technique for guiding biopsy. We previously published our results on US use for biopsy and its utility in improving the diagnostic yield.
We are demonstrating one of the intraoperative applications of ultrasound imaging in neurosurgery. The real-time 2D ultrasound imaging modality for biopsy of intracranial lesions is shown in this video.
A 60-year-old-man, a retired officer, presented with progressive headache, vomiting, forgetfulness, and irrelevant talk for 15 days. He had progressive right-side spastic hemiparesis with upper motor neuron facial palsy for 3 months. He was a wheelchair user and had decreased verbal response with recent memory disturbances.
MRI brain imaging showed a T2W hyperintense lesion in the left temporal and the splenial region, predominantly nonenhancing on post-contrast T1W images. He was started on levetiracetam and dexamethasone preoperatively and evaluated for pre-anesthetic fitness.
He was planned for a left parietal mini-craniotomy and frameless RT-2DUS guided biopsy. Under general anesthesia, the head was positioned with a rotation toward the right. A linear incision was marked over the left parietal region. In a sterile fashion, a mini craniotomy was performed. It was large enough to fit in a curved linear probe with a small footprint (29 mm × 10 mm) and a frequency range of 5–13 MHz (Craniotomy N13C5 transducer, ®BK Medical Denmark) from bk5000 IOS system (® BK Medical, Denmark). The probe is provided with a side attachment for a needle guide. The advantage of a needle guide is that the needle always remains in the scanning plane of ultrasound. It has three slots for passing the biopsy needle corresponding to the three trajectories, visualized as dotted lines on the ultrasound image monitor. Transdural ultrasound was performed to localize the high-grade component (solid tumor) for biopsy. The biopsy area was aligned in the path of one of the three trajectories, and the biopsy needle was advanced under real-time imaging guidance to the biopsy point. Multiple biopsies were performed from the temporal and splenial part of the lesion with a side-cutting biopsy needle. Post-biopsy-check ultrasound showed a small clot at the biopsy point. The craniotomy flap was fixed with plates and screws, and the incision was closed in layers.
Video Link: https://youtu.be/yOJfA3J3Mvc
Video timeline with audio transcript:
This operative video demonstrates a technique of real-time 2D ultrasound-guided biopsy for a multifocal glioma.
(0:00:07) A 60-year-old retired gentleman presented to OPD with progressive headaches, vomiting, forgetfulness, and irrelevant talk for 15 days. On clinical examination, he had right-side spastic hemiparesis with upper motor neuron facial palsy. He was a wheelchair user and had decreased verbal response with recent memory disturbances.
(0:00:31) MRI brain imaging showed a T2W hyperintense lesion in the left temporal and the splenial region, predominantly nonenhancing on post-contrast T1W images. He was started on levetiracetam and dexamethasone preoperatively and evaluated for pre-anesthetic fitness.
(0:00:50) We planned for a left parietal mini-craniotomy and RT-2DUS-guided biopsy of the multifocal glioma.
(0:00:59) He was positioned supine with his head turned to the right side under general anesthesia. Linear left parietal incision was marked over the parietal eminence. In a sterile fashion, a mini-craniotomy was performed. A nursing assistant arranged a BK ultrasound machine with a cranial N13C5 transducer.
(0:01:21) After fixing the US probe with the needle guide, a transdural 2DUS scan was acquired to localize the lesion following craniotomy. The projected path tracker feature of the BK machine was utilized to decide on the trajectory. Here we chose the lateral most trajectory to enter the lesion, avoiding all possible vital structures. A small durotomy was made at the entry point of the needle. A closed side-cutting stereotactic needle attached to a 5cc syringe for the aspiration was inserted through the durotomy slowly in rotatory motion to enter the lesion. After opening the needle, under continuous real-time imaging, multiple biopsies were taken in different meridians during a single insertion of the needle by rotating its cutting surface. The needle was removed slowly in a similar rotatory fashion after closing.
(0:02:15) Post-biopsy 2DUS showed a small clot at the biopsy site and along the needle insertion path. After confirming that representative tissue was biopsied through frozen section analysis, the craniotomy flap was fixed with plates and screws, and the skin was closed in a layered manner.
(0:02:35) The patient was extubated and shifted to the recovery room for observation overnight. No new neurological deficits were noted till discharge.
(0:02:43) These are the references used in this manuscript along with our previous publication on comparative analysis of 2D versus 3D ultrasound-guided biopsy techniques.
We discharged the patient in stable neurological condition on postoperative day 2. Histopathological examination revealed primary glioblastoma, IDH wild type with ATRX loss. He was started on adjuvant chemo-radiotherapy as per standard Stupp protocol.
Pearls and pitfalls
IOUS is an effective and useful intraoperative imaging technique. This imaging technique is advantageous over MR because it is easier, cheaper, and almost universal in all operating setups with real-time imaging guidance, which is practically impossible with MR. The representative yield for our series 2DUS versus 3DnUS-guided biopsy was 98.4%, with a diagnostic yield of 92.8%.
The significant advantage of using real-time ultrasound imaging for biopsy are as follows:
The only real disadvantage of this technique is the necessity to perform a mini-craniotomy instead of a burr-hole performed in other methods. However, the dural opening is only at the entry point of the needle; thus, intradural invasion is similar to that in stereotactic biopsies. In addition, as imaging is real-time, it is operator-dependent and involves an initial learning curve with anatomical orientation and understanding of ultrasound images.
This operative video demonstrated a simple technique of performing RT-2DUS-guided biopsy of deep-seated lesions. Transdural US following craniotomy delineates lesion, and real-time imaging can compensate for the brain shift to target the likely representative tissue for biopsy. BK machine's trajectory guiding feature helps to avoid vasculature (with color Doppler function) and ventricles. With three options available for directing the needle, we can choose the shortest and safest trajectory to the desired point; this lends flexibility to the surgeon, which is not available with other frame-based stereotactic procedures. The needle is always in the plane of insonation as the needle guide is fixed to the probe. This is more advantageous than a freehand needle biopsy in which keeping the needle in the insonating plane is difficult.
The limitation of all biopsy procedures, a nondiagnostic yield, is a limitation of histopathological evaluation rather than the procedure itself when the US is used for real-time imaging as missing the representative tissue is very rare (<2%).
To conclude, RT-IOUS is a safe, simple, and technically reliable real-time imaging technique for biopsy procedures. It is equally effective as other biopsy techniques with the added advantage of real-time imaging.
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Conflicts of interest
There are no conflicts of interest.