Adult cerebellar medulloblastoma: imaging features with emphasis on MR findings

PURPOSE

To describe the MR imaging features of cerebellar medulloblastoma in the adult.

MATERIALS AND METHODS

The neuroimages and records of 15 adults with proved cerebellar medulloblastoma were retrospectively evaluated. In 12 patients, preoperative MR scans were reviewed; nine had Gd-DTPA-enhanced scans.

RESULTS

Of the 12 tumors evaluated preoperatively, eight were hemispheric, two hemispheric-vermian, and two vermian. Tumor margins were well demarcated, except in three cases, two of which had large infiltrative tumors. In 10 cases, tumor extended to the brain surface, and in five of these, contiguity with the tentorium or cerebellopontine angle cistern was such than an extraaxial tumor was considered. The tumors were typically hypointense on T1 but a spectrum was seen on T2-weighted images. Enhancement ranged from minimal and patchy to marked. One tumor became isointense after Gd-DTPA. Other features included cystic changes, hemorrhage, exophytic invasion at the cerebellopontine angle, spinal cerebrospinal fluid seeding, intraventricular seeding, and bone metastasis.

CONCLUSION

Although there is no pathognomonic MR appearance of adult cerebellar medulloblastoma, the finding of a well-demarcated, mild to moderately enhancing hemispheric mass involving the brain surface in a young adult is suggestive of medulloblastoma. Awareness that this tumor may resemble meningioma may avoid misdiagnosis and aid surgical planning.

The split notochord syndrome with dorsal enteric fistula

Split notochord syndrome with dorsal enteric fistula is an extremely rare congenital anomaly that may be associated with meningomyelocele or meningocele, and genitourinary anomalies. This case presented with an additional finding of bladder exstrophy, raising the possibility of a relationship between this syndrome and the OEIS complex.

Intracerebral hemorrhage from a middle meningeal arteriovenous fistula with a giant venous varix

A patient with a congenital arteriovenous fistula between the middle meningeal artery and a cortical vein with a giant venous varix is described. The patient presented with an intracerebral hemorrhage that had been evacuated. Permanent cure of the fistula was achieved without morbidity by embolization with Ivalon particles.

Spontaneous closure of a high-risk dural arteriovenous malformation of the transverse sinus

The case of a 44-year-old woman with tinnitus of her left ear is presented. An arteriogram demonstrated a posterior dural arteriovenous malformation (AVM) on that side with drainage via dilated cortical veins into the superior sagittal sinus. No intervention was undertaken. When angiography was repeated 7 years later, no dural AVM was seen.

Traumatic pseudoaneurysm of the cervical carotid artery: the value of arteriography

A patient who sustained a gunshot wound to the neck and subsequent blunt trauma is presented. No angiogram was performed after the initial injury. Subsequently, the patient developed a cerebral embolus from a thrombus dislodged from a pseudoaneurysm of the cervical carotid artery, resulting in complete occlusion of the distal internal carotid artery. After antiplatelet therapy, the distal internal carotid artery recanalized, and the pseudoaneurysm occluded spontaneously. We stress the need for the use of arteriography in the initial evaluation of penetrating injuries to the neck and the utility of repeated arteriograms for further treatment planning as these traumatic lesions can change with time.

Interventional neurovascular treatment of traumatic carotid and vertebral artery lesions: results in 234 cases

Traumatic injuries to the head and neck that result in arteriovenous fistulae are often difficult to treat by direct surgical access. This is because of anatomic location, instability of the acutely injured patient, and difficulty in localizing the exact site of injury. Between 1974 and 1988, 234 consecutive cases of traumatic injuries to the carotid or vertebral artery were evaluated by our group for intravascular embolization therapy. This included 206 cases of direct and seven cases of indirect carotid-cavernous sinus fistulae and 21 cases of traumatic vertebral fistulae. A variety of devices including detachable balloons, liquid tissue adhesives, microcoils, and silk suture were used with the goal of fistula occlusion and preservation of the parent vessel. This was achieved in 193 cases (82%). In the remaining 41 cases (18%), the carotid or vertebral artery had to be occluded by endovascular occlusion techniques because of extensive vascular injury in 28 cases and subtotal occlusion of the fistula in 13 cases. Complications included transient cerebral ischemia in six cases, pseudoaneurysm formation in five cases, stroke in five cases, and peripheral nerve injury in one case. The development of interventional neurovascular techniques has altered the management of these acutely injured patients. The preferred method for treatment has shifted from direct surgical access under general anesthesia to endovascular therapy under local anesthesia.

Hematoma of optic nerve glioma--a cause for sudden proptosis. Magnetic resonance imaging findings

Optic nerve glioma in patients with neurofibromatosis is a relatively benign neoplasm. It is slow growing and considered by some to be a hamartoma. Clinical presentation usually includes loss of vision and gradual, painless proptosis. We report a case in which abrupt proptosis of the right eye was shown on magnetic resonance imaging to be due to a hemorrhage into the tumor.

Septation in syringomyelia and its possible clinical significance

A 3-year-old boy with a septated syrinx and several other dysraphic features is presented. The literature regarding the cause, diagnosis, and pathology of septation in syringomyelia is reviewed. This case raises two points. First, the septated pattern may be associated with an elevated pressure in the syrinx. Second, despite the septations, the syrinx may communicate freely.

Percutaneous transluminal angioplasty of the carotid artery

Percutaneous transluminal angioplasty (PTA) is being extensively applied to treat arteriosclerotic lesions. However, this application has not been widely accepted for the treatment of carotid artery stenosis. Successful attempts to relieve cerebral ischemia from extracranial carotid arterial stenosis by PTA are reported. Twenty-seven patients with arteriosclerotic stenosis, fibromuscular disease, and Takayasu carotid arterial stenosis were treated by PTA. All anatomic carotid stenotic lesions were corrected without any neurologic complication. Follow-ups ranged from 3 months to 4 years without recurrent symptoms in any patient. These results may suggest that some patients with cerebral ischemia secondary to extracranial carotid artery stenosis may be treated safely and effectively by PTA.

Solitary osteochondroma with spinal cord compression

Osteochondromas are unusual in the spine, and they are very rarely present with compression of the spinal cord. Two cases are reported with delineation of the tumor by metrizamide myelography and computed tomography.

Arterial digital subtraction angiography with particulate intravascular embolization and angioplasty

The authors are reporting their experience with arterial digital subtraction angiography to monitor particular intravascular embolization in hypervascular tumors and malformations and angioplasty. Arterial digital subtraction angiography may reduce the time of waiting for regular film developing and subtraction. The smaller amount of contrast material being used in arterial digital subtraction angiography minimizes the discomfort to the patients. It also prevents further renal damage in those patients with poor renal function. The arterial digital subtraction angiography may detect the early warning signs of embolotherapy. From the past experience, the authors have found that arterial digital subtraction angiography should be considered as a better alternative way to performing the particulate embolization and angioplasty than being monitored by conventional angiography.

Therapeutic embolization for vascular trauma of the head and neck

Therapeutic embolization is an effective and relatively safe method for managing many cases of head and neck trauma. In the last 5 years, 78 traumatic vascular lesions--10 arterial transections and 68 arteriovenous fistula--were treated by intravascular embolization at four medical centers. Selection of embolic materials is discussed and different types of lesions are illustrated. Treatment was successful in every instance. Complications were limited to one case of cerebral infarction and two cases of temporary oculomotor weakness. The indications for embolization have widened beyond life-threatening hemorrhage alone, and continued improvement in techniques and embolic agents should see an increased use of this form of treatment.

A new method for treating carcinomatous biliary obstruction with intracatheter radium

We describe a new method for relieving biliary obstruction due to malignant solid tumors. The method consists of placement of radium needles in a Ring biliary drainage catheter for three days. After removing the radium needles, the catheter is left in place to allow for repair of irradiated tissues, then it is removed. The object is to leave the patient with a patent biliary tree without a biliary drainage prosthesis. The clinical course of six patients treated by this method is described, and the autopsy findings in three cases are outlined. Three patients died with a serum total bilirubin ranging from 1--4.5 mg/100 ml, two to three months after removing the drainage catheter. Two patients died before the bile drainage catheter could be removed. One patient is alive with a bile drainage catheter in place. Possible modifications in technique and catheters are being considered.

Subdural metastases from prostatic adenocarcinoma

Adenocarcinoma of the prostate commonly metastasizes to lymph nodes and bones, with occasional visceral deposits; lesions in the brain are rare. Although leptomeningeal carcinomatosis secondary to prostatic tumor has been reported, discrete cranial dural metastases from prostatic adenocarcinoma have not been described previously. The case of a patient having a unique adenocarcinoma of the prostate with bone, lymph node, and subdural metastatic lesions is presented.

Diagnosis of cerebellopontine angle tumors with small quantities of air

Difficulty in detecting small acoustic neuromas has encouraged us to study patients suspected of having a tumor by air cisternography augmented with computed tomography. Ninety patients were examined without complication. Five cubic centimeter of air was introduced via lumbar puncture and manipulated into the cerebellopontine angle cisterns. Scanning is commenced immediately. Filling of both internal auditory canals and identification of the neurovascular bundle in the cerebellopontine angle cistern was possible in all patients except those with tumors. The diagnostic accuracy, speed, and lack of morbidity have made this procedure the initial radiologic examination at our institution for patients suspected of having acoustic neuroma.

Progressive supranuclear palsy, computed tomography, and response to antiparkinsonian drugs

Three patients with progressive supranuclear palsy demonstrated atrophy of the midbrain, pons, cerebellum, and cerebral hemispheres by computed tomography with horizontal, sagittal, and coronal reconstruction. Benztropine therapy resulted in improvement of speech and gait without significantly affecting the vertical gaze palsy.

Diagnosis of empty sella with small amounts of air at computed tomography

The incidental finding of an enlarged sella turcica on a skull roentgenogram may precipitate a tedious, expensive endocrinological as well as invasive radiological evaluation of an asymptomatic patient. Computed tomography and metrizamide cisternography have been suggested as alternatives to traditional pneumoencephalography. We have found the most direct and definitive study of the "empty sella" to be limited computed tomography after the introduction of a small amount of air by lumbar puncture. The diagnosis is made quickly without morbidity.

Preoperative embolization of meningiomas

Embolization of very vascular meningiomas prior to operation will reduce the loss of blood during operation. The technique of preoperative embolization is discussed, and 11 cases are presented.

New technique for localization of therapeutic emboli using radionuclide labeling

A sensitive method for localizing the resting place of catheter-injected therapeutic gelatin emboli is described. Surgical gelatin (Gelfoam) is labeled with 99mTc and each embolus observed on the persistence scope of a gamma camera after injection. This technique reduces the chance of obstructing blood vessels other than those intended. Two cases of embolization, one arterial and one venous, are illustrated.

Coronal and sagittal reconstruction in computerised tomography

As useful and dramatic as axial computed tomograms are, severe limitations have been encountered. Most of these involve the accurate location of masses and, as in angiography, projections in several planes are essential. Recent advances in both hard and softward allow three millimeter slice thicknesses at low radiation dosage. Coronal and sagittal reconstructions are practical and obtained with ease. The computerized tomogram is invaluable in complementing standard neuroradiological procedures and, in some cases, allows definitive diagnosis. This degree of accuracy is not possible without multiplane reconstructions.