Cancer
Cancer is the uncontrolled growth of abnormal cells in the body. Cancer cells can spread to other parts of the body through the blood and lymph system. There are more than 100 different types of cancer. All cancers begin in cells, and to understand the disease, it’s helpful to know what happens when normal cells become cancer cells:
The body is made up of many types of cells. These cells grow and divide in a controlled way to produce more cells, as they are needed to keep the body healthy. When cells become old or damaged, they die and are replaced with new cells. However, sometimes this orderly process goes wrong. The genetic material (DNA) of a cell can become damaged or changed, producing mutations that affect normal cell growth and division. When this happens, cells do not die when they should and new cells form when the body does not need them. The extra cells may form a mass of tissue called tumor. It is important to note that not all tumors are cancerous and that only through examination by qualified medical professionals can this be determined.
Brain Tumor
A brain tumor is a mass or growth of abnormal cells in your brain. There are many different types of brain tumors, and they can either begin in your brain (primary brain tumor) or cancer can begin in other parts of your body and spread to your brain (secondary, or matastatic brain tumor). A brain tumor can directly destroy brain cells or they can indirectly damage cells by producing inflammation, or compression to other parts of the brain as the tumor grows, causing swelling in the brain and increased pressure within the scull.
Primary brain tumors originate in the brain or close to it, such as in the brain-covering membranes (meninges), cranial nerves, pituitary gland or pineal gland. Primary brain tumors are much less common than secondary brain tumors, in which cancer begins elsewhere and spreads to the brain. Any cancer can spread to the brain, but the most common ones include: breast cancer, colon cancer, kidney cancer, lung cancer, melanoma, neuroblastoma and sarcoma. Brain tumors may occur at any age, but many specific tumors have a particular age group in which they are most common. In adults, glioblastomas and meningiomas are most common.
Here is a selection of conditions and lesions where use of the SonoWand may have an important impact on the outcome:
Glioma
Glioma derives from glial cells, and is a type of cancer that starts in the brain or spine. Gliomas are named according to the cells they resemble and are also classified in 4 grades with different names according to WHO standard:
Pilocytic astrocytoma: Glioma grade 1. The tumor is well demarked, slowly growing and is the most benign of the gliomas. These tumors occur primarily in children and young adults, and are not frequently discovered and treated by surgery. When they are removed, the prognosis is quite good. These tumors are visible on ultrasound and MRI.
Low grade astrocytoma: Glioma grade 2. Malignant, but slow growing tumor that should be treated. The patient probably has a quite good prognosis if the resection can be done as radical as possible. These tumors can be seen quite well on ultrasound. The value of ultrasound-guided resection is expected to be particularly high for these lesions.
Anaplastic astrocytomas: Glioma grade 3. Aggressive and malignant tumor, relatively fast growing. The tumor may grow so fast that the vascular supply network for the tumor does not develop fast enough to keep the tumor alive. The central part of the tumor may “die” and leave rather liquid filled, necrotic or cystic areas behind. Such areas appear rather black or hypoechoic (weak echoes) on ultrasound. Beside this, the tumor itself is normally very well visualized on ultrasound. Again there is a good correspondence between ultrasound and MR T2 and MRT1 (the latter requires contrast agent). These tumors are often surrounded by edema that could be misinterpreted as being low grade tumor fractions. Care should be taken when using ultrasound for resection control towards the end of resection. Side by side comparison with preoperative MR is useful in this respect.
Glioblastomas: Glioma, grade 4. Very aggressive and malignant tumor, fast growing. Some groups consider the value of surgery for this type of malignant tumor to be limited, and offer the patient only a biopsy in order to make a confident diagnosis. Other centers offer tumor resection with the intention of improving the quality of life for the patient. The surgeon will normally be on the conservative side in terms of total resection, i.e. spare vital brain function if the tumor seems to infiltrate normal brain structures. Recent studies (2007) show however that patients may benefit from radical resection, so there may be a change in attitude in years to come.
Glioblastomas are normally very well visualized on ultrasound, MR T1 (with contrast) and MR T2. The value of ultrasound-guided surgery will be significant if it can be proven that a “total” resection is beneficial for the patient.
Metastasis
These tumors are malignant cancer tumors, but they originate from a different organ in the body such as liver, lung, stomach, breast, skin etc. They are normally well demarcated and well visualized on MR and ultrasound. The consistence may vary from soft (can be removed by a suction device) to dense and hard, even calcified (must be removed with ultrasound aspirator or diathermy). It is important to obtain a clean resection border in order to reduce the risk of residual tumor growth.
Skull base Meningiomas
Some meningiomas originate from cells on the skull base. These tumors can be very large, and take long time to remove. Even though they are easy to find, it might be helpful with intraoperative imaging in order to see how much tumor tissue that is left. These tumors infiltrate the nerves, and it is a challenge not to destroy the nerve. Ultrasound angiography may be helpful to keep track of nearby blood vessels. Skull base meningiomas originate from the bone, and get their primary blood supply from the attachment with the bone. Some surgeons therefore start by “disconnecting” the tumor from the bone in order to control major bleeding in the initial phase of resection.
Navigated CUSA (suction instrument) enables the surgeon to remove skull base meningiomas in a slightly different way than normal. When an access path to the tumor has been established (as normal), the CUSA tip can be inserted into the tumor and the central part of the meningioma can be removed quickly and safely by means of online image guidance. The navigation monitor provides information about the position of the CUSA tip relative to the tumor border as well as the distance to vital blood vessels. When the central part of the tumor has been removed, the tension on the surrounding brain drops, and the remaining part of the tumor including the capsule can then easily be removed under microscope vision. The method seems to allow tumor removal with less morbidity and risk.
Other cerebral lesions:
Cysts
A collection of liquid (encapsulated by a thin membrane). A cyst takes volume from the normal brain and may cause an increase in intracranial pressure. Cysts are very easy to see on medical imaging, and image-guided navigation is relevant for treatment.
Abscesses
A collection of pus caused by an infection most often bacterial. Characteristic appearance on MR and ultrasound is a dark round lesion with a bright ring around. If the pus contains cells of a certain size, a homogenous speckle patters can be seen on ultrasound. Edema may surround the abscess.
Cerebrovascular lesions:
AVM (Arterio Venous Malformation)
An abnormal collection of arteries and veins. An AVM is an area that lacks the capillaries and they can develop to a tumor (“ball”) of arteries and veins where arterial blood is pumped directly over to the venous side without passing through normal tissue. The tissue in between the AVM is denoted the “nidus”. Such lesions grow slowly, but will normally be treated by embolization and/or surgery. If not, there is a risk of rupture and development of an intracerebral hematoma.
An AVM will normally have one or more feeding arteries, and during surgical resection, it may be beneficial to localize these feeders and secure them (put on a metal clip and stop the blood flow). When the feeders are secured, the pressure in the AVM will drop, and the lesion can be removed more safely and will less harm to the surrounding normal brain. There seems to be an indication for using navigation with 3D angiography in order to identify and localize such feeders. The role of 3D ultrasound in this respect is currently under investigation in Trondheim.
Aneurysm
A weakening of an arterial wall in combination with the blood pressure generates a pathological extension on the vessel, a “balloon”. If not treated, such lesion may rupture and cause an intracerebral hematoma. The most common way of treating aneurysms has been to perform surgery and put a clip over the “neck” of the aneurysm. However, in recent years it has been more common to treat aneurysms by implanting a “coil” (metal wire) inside the “balloon” using interventional techniques. The coil causes the blood to coagulate and the pressure on the vessel wall to drop. Most aneurysms are easy to find, but in some cases blood flow control before and after aneurysm clipping might be helpful. This is an application where the use of SonoWand is under investigation.
Cavernous Hemangiomas (cavernomas/ cavernous angioma)
Cavernomas are clusters of abnormal blood vessels. A typical cavernoma looks somewhat like a raspberry, but it can range in size from microscopic to several centimeters in diameter. It is made of multiple little bubbles (caverns) of various sizes, filled with blood and lined by a special layer of cells (endothelium). These cells are similar to those that line normal blood vessels, but the bubble-like structures of a cavernous angioma are leaky and lack the other layers of normal blood vessel wall. A cavernous angioma can cause seizures, stroke symptoms, hemorrhages, and headache.
A cavernous hemangioma will normally be well defined, and removed in one piece. However, they can be fragmented with small layers of gliosis in between the lobes. The lesion is well demarcated and differs dramatically from normal tissue in color and texture. There is a need for intraoperative imaging and navigation in order to perform quality control and check that everything has been removed. Cavernous angiomas are normally well visualized on ultrasound, but it can be difficult to distinguish from gliosis. Small cavernous angiomas can be difficult to find without navigation, so even for localization, navigation by preoperative MRI or ultrasound makes sense. Since ultrasound easily detects such lesions, preoperative MRI could be eliminated in order to save resources.
Please note: Information found on this website is related to SONOWAND AS products, and is meant for general information only. SONOWAND does not practice medicine, and we strongly advise you to talk to your doctor about your situation. Information on this website cannot replace the relationship you have with your medical professional.
