Optic Nerve Glioma

Optic Nerve Glioma

Optic nerve glioma is the most common primary neoplasm of the optic nerve causing decreased visual sharpness in the affected eye. Benign optic glioma occurs most often in children, more females with an average age of five years. Another form, aggressive glioma, which is unusual is most common in adults, more males with a median age of fifty-two years; it is often terminal, even with treatment. .
From 10-38% of children with optic nerve glioma is also known to have neurofibromatosis type 1 (NF-1) or, in some cases, the more recently described hybrid phakomatosis. In 66% of NF-1 patients with optic nerve glioma, the growth involves the intraorbital optic nerve. In 10-20%, the tumor is confined to the orbit, with the remainder of these patients showing involvement of the intracranial compartment.
Optic nerve gliomas represent 4% of orbital tumors, 4% of intracranial gliomas, and 2% of intracranial tumors. They also include two thirds of all primary optic nerve tumors.
Benign optic glioma develops gradually, if at all. Yet, some lesions can grow, causing visual impairment, so follow-up is recommended.
Twenty percent of optic gliomas that extend to the optic chiasm or outside, into the optic radiations, exhibit a more aggressive path.
In the absence of NF-1, the optic chiasm is most usually involved, as is, less often, the intraorbital optic nerve. Optic nerve glioma may involve different sections of the retrobulbar visual pathway, including the optic nerve, chiasm, tracts, and radiations. Malignant lesions can occupy the hypothalamus, basal ganglia, and internal capsule directly, or they may extend to the leptomeninges or subpial surfaces.
In most young patients with optic glioma, the symptom is painless proptosis. Optic atrophy is common, as is reduced visual sharpness, (which may be a late symptom). A large lesion may compress the optic chiasm, causing nystagmus. Hypothalamic symptoms, such as changes in appetite or sleep, also may occur. Massive lesions may compress the third ventricle, resulting in obstructive hydrocephalus accompanied by headache, nausea, and vomiting.
In adult patients, bilateral vision loss is a common early finding because most lesions involve the optic chiasm.
Contrasted computed tomography (CT) scanning can be used to differentiate confined involvement of optic nerve glioma within the orbit and the presence of an intraconal mass. CT scanning can distinguish a faint attrition or growth of the optic canal. In addition, fine calcification, which may help to identify a lesion as a meningioma rather than a glioma, is visualized best through CT scanning.
Findings:
In children, unenhanced CT scans normally reveal an evident, diffuse growth of the optic nerve, with typical twisting. The enlargement may be tubular, fusiform, or excrescent.
Areas of lucency may result from mucinous or cystic changes.
Approximately 50% of the lesions reveal enhancement; this characteristic is more common with intracranial (especially retrochiasmatic) extension.
Calcifications are unusual.
Improper examination techniques, including failure to administer contrast or obtain thin sections, can lead to a false-negative diagnosis.
Magnetic Resonance Imaging (MRI), however, is the preferred method for definitive evaluation of optic nerve glioma. Both the intraorbital lesion and its intracranial degree can be effectively differentiated through MRI. When evaluating the orbit, gadolinium-enhanced T1-weighted images with fat saturation can define the degree of aggressive glioma. Intracranially, MRI allows better evaluation of the optic nerve, chiasm, tracts, geniculate body, and optic radiations and shows even slight lesions of the optic nerve than does CT.
Findings:
On T1-weighted images, optic nerve gliomas are usually isointense to the cortex and hypointense to white matter.
Invariably, the lesions are hypointense to orbital fat.
On T2-weighted images, lesions show a varied appearance that is isointense to hyperintense relative to white matter and the cortex.
Following contrast administration, intense enhancement is common.
A diagnosis of NF-1 may be supported by several findings including the following:
Bilateral optic nerve gliomas.
Spongiform changes (hyperintensity on T2-weighted images) in the cerebellum, brain stem, basal ganglia, thalamus, periventricular white matter, and corpus callosum
Adult lesions may involve the orbital, intracanalicular, or prechiasmal portions of the optic nerve, resulting in enlargement; they may exhibit retrochiasmatic extension as well).
Usually, the lesions are hypointense to isointense relative to the optic nerve on T1-weighted images and are hyperintense to it on T2-weighted images. Enhancement is homogeneous and intense.
Patients without NF-1 show cystic components more commonly at T2 -weighted imaging.
The diagnosis may be made with a high level of confidence when the lesion involves the optic chiasm and retrochiasmatic optic pathway.
When limited entirely to the orbit, the lesion may imitate optic neuritis, pseudotumor, lymphoma, or optic nerve meningioma. Characteristically, meningioma, the main differential diagnostic consideration, is distinguished by the "tram-track" sign, with enhancement of the periphery of the nerve–optic sheath unit. Conversely, enhancement in optic nerve glioma is more uniform. Isolated growth of the optic nerve sheath also may present diagnostic complexity; however, this enlargement can generally be distinguished by its signal characteristics, which follow fluid signal on all MRI pulse sequences.
In most occasions, the diagnosis can be made with greater assurance using MRI than it can with CT scanning.
A false-positive diagnosis can occur as an effect of unilateral optic nerve enhancement or other unilateral disorders, such as optic meningioma, vascular lesions, neuritis, pseudotumor, lymphoma, and sarcoidosis. In addition, subtle nerve enhancement occasionally may develop in normal individuals.
Improper examination procedures, including failure to administer contrast, use fat saturation, or obtain thin sections, can result in a false-negative diagnosis.
Local surgical therapy for large lesions may cause significant morbidity, including hypothalamic dysfunction. Stereotactic radiation or gamma-knife therapy also can produce complications, including decreased visual perception, radiation-induced optic neuritis, and ophthalmic artery vasculopathy.
Despite aggressive radiation, chemotherapeutic, or surgical treatment, aggressive glioma is an almost uniformly fatal disease.
Information By: Emory University School of Medicine.org

Pituitary Gland Tumors

Pituitary Gland Tumors

The pituitary gland is a tiny bean -shaped gland located at the base of your brain, posterior to your nose and between your ears. Its hormones help regulate important functions, such as growth, blood pressure and reproduction. Sometimes pituitary tumors can generate excess amounts of hormone and sometimes, pituitary tumors can limit the pituitary gland, causing it to produce lower levels of hormones (hypopituitarism), which usually originates in the anterior pituitary (adenohypohysis). A tumor can also compress the optic nerve — the nerve that transmits visual information from the eye. Most pituitary tumors are benign, nonspreading (adenomas). The cause of pituitary tumors remains unknown.

Signs and symptoms

Pituitary tumors that produce hormones are called functioning tumors and tumors that don't produce hormones are known as nonfunctioning pituitary tumors. Various types of functioning tumors can grow in your pituitary gland, each causing particular signs, and symptoms:

Adrenocorticotropic hormone-producing tumors. These pituitary tumors create the hormone adrenocorticotropin, which stimulates your adrenal glands to produce the hormone cortisol. When your adrenal glands make too much cortisol, a condition called Cushing's syndrome takes place. Signs and symptoms of Cushing's syndrome may consist of weight gain around your midsection and upper back, inflated facial roundness, a typical bulge on the upper part of your back, high blood pressure, muscle weakness and thinning of your skin.

Growth hormone-producing tumors. These tumors produce extra growth hormone (acromegaly), which may include coarsened facial features, enlarged hands and feet, high blood pressure and heart problems. Accelerated and extreme growth (gigantism) may occur in children.

Prolactin-producing tumors. Overproduction of prolactin (hyperprolactinemia) from a pituitary tumor (prolactinoma) can cause a reduction in normal levels of sex hormones — estrogen in women and testosterone in men.

In women, prolactinoma may cause irregular menstrual periods (oligomenorrhea), lack of menstrual periods (amenorrhea) and milky discharge from the breasts (galactorrhea).
In men, a prolactin-producing tumor may cause male hypogonadism, such as enlarged breasts (gynecomastia), erectile dysfunction (ED) or impotence, infertility, decrease in body hair, and loss of interest in sexual activity.

Thyroid-stimulating hormone-producing tumors. When a pituitary tumor overproduces thyroid-stimulating hormone (thyroxin). This is an unusual cause of hyperthyroidism, or overactive thyroid disease. Hyperthyroidism can increase the body's metabolism, causing sudden weight loss, a rapid or irregular heartbeat, and nervousness or irritability.

Functioning and nonfunctioning pituitary tumors may cause other signs and symptoms, including:
Headache
Vision changes, such as decreased peripheral vision or double vision
Seizures
Clear, watery nasal drainage
Hair loss
Cold intolerance
Constipation
Irritability
Weakness
Fatigue
Nausea
Vomiting
Low blood pressure

Risk factors
Even though pituitary tumors can happen at any age, they're most likely to occur in older people. People with a family history of multiple endocrine neoplasia type 1 (MEN 1) have an increased risk of pituitary tumors. In MEN 1, multiple tumors occur in different glands of the endocrine system.

Screening and diagnosis
Blood tests detect the overproduction or lack of hormones as a result of a pituitary tumor.
Brain imaging. A computerized tomography (CT) or magnetic resonance imaging (MRI) scan of the brain can identify a pituitary tumor.

Vision testing. These tests can conclude if development of a pituitary tumor has harmed the sight or peripheral vision.
Bone imaging. In children, an X-ray of the hand and wrist can determine whether bone growth is normal.

Treatment
Treatment for a pituitary tumor relies on the kind of tumor, its size, and how far it has spread into the brain. The age and general health also need to be considerations. Because pituitary tumors can cause severe problems by putting pressure on the brain, treatment often is essential. Early detection of pituitary tumors is important to effective treatment.
Doctors usually use surgery, radiation therapy, and medications, either alone or in combination, to treat a pituitary tumor and return hormone production to normal levels.

Surgery

The most common treatment for pituitary tumors is surgery. Surgery for a pituitary tumor normally is necessary if the tumor is pressing on an optic nerve, which can cause loss of vision. The effectiveness of surgery depends on the tumor type, its location, its size, and whether the tumor has spread. The two most important surgical procedures for treating pituitary tumors are:
Transsphenoidal hypophysectomy. With this method, a doctor usually can reach and remove the tumor through the nose and sinuses without an external incision, but very large tumors may be complicated to remove with this process, particularly if a tumor has occupied close to nerves or brain tissue.
Transcranial hypophysectomy. Through this procedure, the larger more difficult tumor is removed through the upper part of the skull by an incision in the scalp.

Radiation therapy

Radiation therapy uses high-energy X-rays to destroy tumors. It can be used after surgery or as main treatment only if surgery isn't an alternative. Radiation therapy can be helpful if a tumor reoccurs after surgery and causes signs and symptoms that medications don't ease.

Types of radiation therapy include:
External beam radiation. This kind of radiation therapy delivers small amounts of radiation over a period of time. As this therapy is often efficient, it may take years to completely control the tumor growth and hormone production. Radiation therapy may also damage remaining normal pituitary cells and normal brain tissue, mainly near the pituitary gland.
Gamma-knife radiosurgery. This type of radiation therapy focuses radiation beams exactly on the tumor without an incision. With gamma-knife radiosurgery, a small amount of radiation affects the healthy tissue surrounding the tumor, reducing the harm to normal tissue, but this therapy can’t be used if the tumor is close to an optic nerve or another sensitive structure.

Drug TherapyTreatment with medications (drug therapy) may help to stop excess hormone secretion and sometimes decrease certain types of pituitary tumors:
Prolactin-producing tumors (prolactinomas). The drugs bromocriptine (Parlodel) and cabergoline (Dostinex) can treat these types of tumors by reducing prolactin secretion and often decreasing the size of the tumor. These medications are often so successful in treating these kinds of tumors that surgery isn't necessary.
Growth hormone-producing tumors. Two types of medications are used for these kinds of pituitary tumors. Drugs known as somatostatin analogs (Sandostatin, others) cause a reduction in growth hormone production and may decrease the size of the tumor. Pegvisomant (Somavert) obstructs the result of excess growth hormone on the body. These drugs are helpful if surgery has been ineffective in regulating growth hormone production.
If a pituitary tumor has resulted in reduced hormone production, hormonal replacement may be necessary to sustain normal hormone levels.

Observation
In observation, regular follow-up tests are needed to monitor for evidence of progression of the pituitary tumor and medications, radiation therapy, and surgery aren't used. Observation may be the option if the tumor isn't causing any signs or symptoms.
Observation may be mainly appropriate due to age and/or poor health. Numerous people with pituitary tumors function normally without treatment and without the tumor causing other problems.

Pituitary Tumor Information from : Eighth Edition Profession Guide to Diseases by: Lippincott Williams and Wilkins and from : mayoclinic.org

Acoustic Neuroma

Acoustic neuroma

Acoustic neuroma is a noncancerous (benign) tumor that extends on a section of the eighth cranial nerve, (which runs from your brain to your inner ear) and controls equilibrium and hearing. Also known as vestibular schwannoma, acoustic neuroma is one of the most common types of brain tumors. Though, these tumors are unusual, occurring in about one person in 100,000.

Signs and symptoms

The signs and symptoms of acoustic neuroma are produced from the tumor pressing on the hearing segment of the eighth nerve. Most acoustic neuromas increase slowly, over many years to become large enough to cause signs and symptoms. Most likely observed in people between ages 30 and 60, acoustic neuromas are uncommon in children, and a higher incidence of occurring in women. In unusual cases, an acoustic neuroma may develop large enough (up to 6 centimeters) to compress on the brainstem and be critical

For some people, the tumor remains so tiny ( less than 1.5 centimeters) it never causes problems. They may need no treatment other than regular monitoring by their doctor .In unusual cases, an acoustic neuroma may develop large enough (up to 6 centimeters) to compress on the brainstem and be critical. Also, large tumors can stop cerebrospinal fluid flow which can cause increased fluid pressure in skull (hydrocephalus). If they need treatment, the choices include radiosurgery and surgical removal.

Signs and symptoms include:

* Permanent Hearing loss, typically gradual — although in some cases sudden — and occurring on only one side or more prominent on one side
* Ringing (tinnitus) in the affected ear
* Dizziness (vertigo)
* Loss of equilibrium
* Facial numbness and tingling
* Headaches
* Mental Confusion

The cause of acoustic neuromas is unknown. But, the tumors, in unusual cases, are a sign of neurofibromatosis 2, a genetic disorder that involves the development of tumors on the vestibulocochlear nerve (bilaterally).

Diagnosis

Because signs and symptoms of acoustic neuroma are likely to develop slowly and because hearing loss, tinnitus and dizziness can be signs of other middle and inner ear problems, it may be complicated for the doctor to identify the tumor in its beginning stage. Acoustic neuromas often are found during testing for other conditions.

* Scans. Magnetic resonance imaging (MRI) or computerized tomography (CT) scans of the head can provide images that confirm the presence of an acoustic neuroma.
* Hearing test (audiometry). During this test performed by a hearing specialist (audiologist), the patient wears earphones and hears sounds directed to one ear at a time. The audiologist presents a range of sounds of different tones and asks them to specify each time they hear the sound. Each tone is repeated at soft levels to find out when they can barely hear. The audiologist also will present various words to determine their hearing ability.
* Electronystagmography (ENG). This test assesses balance (vestibular) function by identifying abnormal rhythmic eye movement (nystagmus) often present with inner ear conditions. The test measures involuntary eye movements while stressing balance in various ways.
* Brainstem auditory evoked response (BAER). This test tests hearing and neurological functions. Electrodes on the scalp and earlobes capture the brain's responses to clicking sounds heard through earphones and record the responses on a graph.

Treatment

There are three choices for managing an acoustic neuroma: observation to determine whether it's growing and how fast, radiation and surgical removal.

Monitoring
If it is a small acoustic neuroma that isn't growing or is growing slowly and causes few or no signs or symptoms, the doctor may decide to monitor it, especially if in an older adult or otherwise not a good candidate for treatment.

The doctor may suggest regular imaging and hearing tests to determine whether the tumor is growing and how quickly. If the scans show the tumor is growing or if the tumor causes progressive hearing loss or other difficulties, treatment may be necessary.

Radiation
Several forms of radiation are used to treat acoustic neuromas. One, a procedure called gamma-knife radiosurgery, enables doctors to deliver radiation accurately to a tumor without making an incision. The doctor attaches a lightweight head frame to the numbed scalp. Using imaging scans, the doctor localizes the tumor and then plots where to apply the radiation beams. This procedure often is performed under local anesthesia.

The purpose of radiosurgery is to stop the growth of a small tumor. It also may be used for residual tumors, portions of a tumor that traditional brain surgery can't remove without damaging brain tissue.

It may take weeks, months, or years before the effects of radiosurgery become evident. The doctor will monitor the progress with follow-up imaging studies.

Immediate side effects of gamma-knife procedures are minimal and may include nausea, neck stiffness, and pain where the frame was attached to the scalp. Long-term risks may include facial paralysis and hearing loss.

Surgical removal
The purpose of surgery is to remove the tumor and maintain the facial nerve to prevent facial paralysis and preserve hearing. Performed under general anesthesia, this type of surgery involves removing the tumor through an incision in the skull. Recovery may take six to 12 weeks.

Risks include infection, bleeding, and reaction to the anesthesia. As with radiosurgery, there is a risk of hearing loss and facial paralysis. The patient is not likely to regain hearing lost as a result of the acoustic neuroma.

Acoustic Neuroma Information from: Eight Edition Profession Guide To Diseases by: Lippincott Williams and Wilkins and from: mayoclinic.org

Meningiomas

Meningiomas are usually slow-growing tumors that develop from the meninges, the protective layer of the brain and spinal cord. Meningomas account for about 20 percent of primary brain tumors and are most likely found in middle-aged or elderly adults, more commonly in women than men. Although they are almost always benign, meningiomas can be difficult to remove completely and can recur.


Diagnosing a brain tumor usually involves several steps. The physician may perform a neurological exam, computerized tomography (CT), magnetic resonance imaging (MRI) scan, angiogram and head and skull x-rays.


A meningioma can cause a diversity of symptoms because it can directly press on brain tissue, damaging or destroying areas responsible for sight, movement, balance, speech, hearing, memory or behavior.


Brain tumor symptoms initially may be vague and come-and-go, delaying diagnosis. Other diseases can cause similar symptoms.


Symptoms can include:
Headaches
Problems with memory, concentration and/or forming words
Personality changes
Vision problems (blurred or double vision, loss of peripheral vision)
Gradual loss of sensation or movement in an arm or leg
Loss of balance or hearing
Difficulty swallowing
Drowsiness
Seizures
Decreased sense of smell


Initial Treatment Steps
Steroid medications may be needed to reduce swelling and inflammation of brain tissue.
Anticonvulsant medications may be prescribed to help control seizures.
A shunt may be inserted if the tumor has resulted in a buildup of fluid in the brain (hydrocephalus). The tube allows excess fluid from the brain to drain into the abdominal cavity where it is reabsorbed.


TREATMENT
Surgery is usually the first approach. Because meningiomas tend to have well-defined edges and do not invade the brain, complete removal is sometimes possible. The standard treatment is to remove the tumor, the portion of the lining of the brain or spinal cord to which it is attached and any bone involved.
Many of these tumors are at the base of the brain and are located near cranial nerves and blood vessels and surgery is more complicated because of the risk of damaging the nerves and blood vessels. Complete surgical removal is sometimes not possible.
Even with removal, meningiomas are not always cured, the recurrence rate varies from 10 to 20 percent (measured over 10 years). When the entire tumor is not removed, the recurrence rate is higher.


Computer-Assisted Surgery for Tumor Removal
Computer-assisted tumor removal (volumetric stereotactic resection) is a surgical method that uses computer-generated models of the tumor built from data obtained by computer imaging techniques. This allows the neurosurgeon to simulate the surgical procedure beforehand to reach a brain tumor using the least invasive route possible.


Radiation
Radiation uses high-energy X-rays to destroy meningioma cells and often is used to destroy any remaining tumor cells that could not be removed surgically.


Stereotactic Radiosurgery
The treatment precisely focuses radiation beams to the tumor. (Gamma Knife™ surgery )
This treatment shows a decreased incidence of cranial nerve damage following radiosurgery and an improved chance that the tumors will not recur.
The advantage of stereotactic radiosurgery is that surrounding, healthy tissue receives minimal radiation compared to the tumor.


Fractionated Stereotactic Radiosurgery (FSR)
FSR provides multiple smaller treatments to spare the normal tissues but destroy the meningioma.
For this procedure, the patient is fitted with a plastic mask that aids in positioning and locating the tumor during treatment. The treatment is given in several smaller units called "arcs." The number of treatments depends on the size and location of the meningioma.


External-Beam Radiation
This traditional form of radiation therapy delivers radiation from outside the body. The radiation usually involves treatments five days a week for a length of time determined by the type of tumor. External beam radiation is less precise, but allows a wider margin of tissue around the tumor to be treated.


Chemotherapy and Other Drug Therapy


Combination Treatments are also used.

Introduction

Hi! My name is Sheila and I work for a mobile PET/CT company. I travel to Southern IN,IL and Western KY hospitals and imaging centers and have been working for them for 4.5 years. I have been a Radiologic and Nuclear Medicine Technologist for over 25 years and really enjoy doing PET/CT. I am taking this class to help my career since CT and MRI have merged with PET. Also, some sites are utilizing their PET/CT scanners for CT exams only at times. So I hope to gain some knowledge of CT and MRI with this class.