Contrast-enhanced gradient-echo MR imaging of the head and neck: experimental and clinical assessment.

To clarify the enhancement pattern of gradient-echo (GE) MR imaging, phantom experiments and 24 clinical examinations of the head and neck region were performed. Both long repetition time (TR) GE and short TR GE pulse sequences demonstrated an enhancement pattern similar to T1-weighted spin-echo imaging in phantom experiments, although the signal intensity of water and gadopentetate dimeglumine (Gd) solution was higher and the signal intensity of fat was lower with the GE technique. In clinical examinations, contrast-enhanced GE imaging was beneficial for tumors within fatty tissue, and for tumors with calcification or other magnetic susceptibility difference.

Intraocular hemorrhage and mimicking lesions: role of gradient-echo and contrast-enhanced MRI.

Intraocular hemorrhage and mimicking lesions on precontrast spin-echo magnetic resonance images were examined with contrast material and/or gradient-echo pulse sequence. Twenty-two melanomas, nine retinoblastomas, four hemorrhages, one metastasis, and one toxocara endophthalmitis were examined. With contrast material, all tumors demonstrated enhancement, whereas hemorrhage did not. Retinoblastomas demonstrated a heterogeneous enhancement pattern. Computed tomography demonstrated corresponding intratumoral calcifications at the areas of no enhancement. Gradient-echo images demonstrated a heterogeneous pattern in the majority of the lesions compared to spin-echo images. However, relatively characteristic small round areas of signal drop-off representing calcification were observed in about half of the retinoblastomas.

Lateral lumbar synovial cyst computed tomography diagnosis.

A symptomatic synovial cyst was preoperatively misdiagnosed because of its lateral location. This case illustrates another lesion to include in the differential diagnosis of masses lateral to the neural foramen in the lumbar spine in patients with degenerative facet arthritis.

Posttraumatic cerebral infarction diagnosed by CT: prevalence, origin, and outcome.

Posttraumatic cerebral infarction is a recognized complication of craniocerebral trauma, but its frequency, cause, and influence on mortality are not well defined. To ascertain this information, all cranial CT studies demonstrating posttraumatic cerebral infarction and performed during a 40-month period at our trauma center were reviewed. Posttraumatic cerebral infarction was diagnosed by CT within 24 hr of admission (10 patients) and up to 14 days after admission (mean, 3 days) in 25 (1.9%) of 1332 patients who required cranial CT for trauma during the period. Infarcts, in well-defined arterial distributions, were diagnosed either uni- or bilaterally in the posterior cerebral (17), proximal and/or distal anterior cerebral (11), middle cerebral (11), lenticulostriate/thalamoperforating (nine), anterior choroidal (three), and/or vertebrobasilar (two) territories in 23 patients. Two other patients displayed atypical infarction patterns with sharply marginated cortical and subcortical low densities crossing typical vascular territories. CT findings suggested direct vascular compression due to mass effects from edema, contusion, and intra- or extraaxial hematoma as the cause of infarction in 24 patients; there was postmortem verification in five. In one patient, a skull-base fracture crossing the precavernous carotid canal led to occlusion of the internal carotid artery and ipsilateral cerebral infarction. Mortality in craniocerebral trauma with complicating posttraumatic cerebral infarction, 68% in this series, did not differ significantly from that in craniocerebral trauma patients without posttraumatic cerebral infarction when matched for admission Glasgow Coma Score results. Thus, aggressive management should be considered even in the presence of posttraumatic cerebral infarction.

Posttraumatic cerebral infarction diagnosed by CT: prevalence, origin, and outcome.

Posttraumatic cerebral infarction is a recognized complication of craniocerebral trauma, but its frequency, cause, and influence on mortality are not well defined. To ascertain this information, all cranial CT studies demonstrating posttraumatic cerebral infarction and performed during a 40-month period at our trauma center were reviewed. Posttraumatic cerebral infarction was diagnosed by CT within 24 hr of admission (10 patients) and up to 14 days after admission (mean, 3 days) in 25 (1.9%) of 1332 patients who required cranial CT for trauma during the period. Infarcts, in well-defined arterial distributions, were diagnosed either uni- or bilaterally in the posterior cerebral (17), proximal and/or distal anterior cerebral (11), middle cerebral (11), lenticulostriate/thalamoperforating (nine), anterior choroidal (three), and/or vertebrobasilar (two) territories in 23 patients. Two other patients displayed atypical infarction patterns with sharply marginated cortical and subcortical low densities crossing typical vascular territories. CT findings suggested direct vascular compression due to mass effects from edema, contusion, and intra- or extraaxial hematoma as the cause of infarction in 24 patients; there was postmortem verification in five. In one patient, a skull-base fracture crossing the precavernous carotid canal led to occlusion of the internal carotid artery and ipsilateral cerebral infarction. Mortality in craniocerebral trauma with complicating posttraumatic cerebral infarction, 68% in this series, did not differ significantly from that in craniocerebral trauma patients without posttraumatic cerebral infarction when matched for admission Glasgow Coma Score results. Thus, aggressive management should be considered even in the presence of posttraumatic cerebral infarction.

Intramedullary and extramedullary schwannoma of the cervical spinal cord--case report.

Intramedullary schwannomas and neurofibromas are rare tumors. Only two cases have been reported as having both an intramedullary and extramedullary component. We have managed the case of a 15-year-old girl with a schwannoma that appeared to track along the sensory nerve root into the spinal cord. The clinical presentation in this case was that of motor weakness and atrophy, sensory abnormalities, and, late in the course, pain. Magnetic resonance imaging with gadolinium enhancement was better than myelography and computed tomography at delineating the intramedullary extent of the tumor. The tumor was removed microsurgically at two operative sittings. Reports of this unusual pathology are reviewed.

Titanium wire internal fixation for stabilization of injury of the cervical spine: clinical results and postoperative magnetic resonance imaging of the spinal cord.

Nine patients with dislocation of the cervical spinal with posterior ligamentous damage were treated with posterior internal fixation using a twisted pair of 22-gauge titanium wires and iliac crest bone fusion. Fixation using the titanium wire was compared with fixation using stainless steel wire for differences in surgical insertion, long term stability of bony fusion, and postoperative magnetic resonance imaging (MRI) artifacts near the implanted wire. MRI of the cervical spine is valuable for diagnosing the acute and chronic consequences of traumatic cervical spinal injury by providing anatomic evaluation of both the spinal cord and the supporting bony/ligamentous structures in the neck. Because MRI is an accurate and sensitive noninvasive test, it is especially useful for the long-term serial assessment of the region near the cervical dislocation site to detect the sequelae of spinal cord injury, including syrinx, arachnoid cyst, cord tethering, and persistent mechanical impingement on the spinal cord or spinal roots. Previous attempts at our institution to obtain useful MRI scans of the cervical region adjacent to stainless steel wires after posterior wire fixation have failed due to marked imaging artifacts from the ferromagnetic properties of these wires. Our substitution of biocompatible titanium wire (Titanium 6 A1-4V ELI alloy, Specialty Steel and Forge, Leonia, New Jersey) for stainless steel wire produced identical immediate stabilization and ultimate bony fusion of the fracture and yielded minimal MRI artifacts overlying the immediately adjacent spinal cord and neural canal; however, the installation was technically more difficult, because of the titanium wire's greater stiffness.(ABSTRACT TRUNCATED AT 250 WORDS)

Protocol-driven radiologic evaluation of suspected cervical spine injury: efficacy study.

The American College of Surgery currently recommends routine performance of lateral cervical radiography of C-1 to C-7 for all patients admitted with a history of major blunt trauma. A survey of 125 North American hospitals with experience in acute trauma care revealed that 96% obtain cervical radiographs as a routine or protocol study on all patients who have suffered major blunt trauma. To ascertain the cost-benefit effect of this practice, a prospective study was conducted during a 19-month period to compare the results of admission bedside clinical assessment of the cervical spine and the outcome of cervical radiography and computed tomography (CT) performed on 408 patients admitted with a history of major blunt trauma. Among these patients, there were 138 (34%) who were judged to be mentally alert and without symptoms referable to cervical spine injury. CT was performed after cervical radiography to adequately visualize the lower cervical spine (132 patients) or to clarify uncertain radiographic findings (six patients). One nondisplaced transverse process fracture of C-7 was detected (a prevalence of less than 1% of asymptomatic patients). The combined cost of cervical radiography and CT for the 138 asymptomatic patients was $59,202. These results call into question both the cost and clinical efficacy of routine or protocol-driven cervical spine imaging for all patients who have sustained major blunt trauma and support the value of careful bedside clinical assessment of the cervical spine in mentally alert blunt-trauma victims.

Bilateral granular cell tumors of the posterior mediastinum.

Granular cell tumors are uncommon and generally benign lesions that are commonly accepted to be of Schwann cell origin. These tumors occur most frequently in the skin and oral cavity and are generally asymptomatic. However, when signs and symptoms occur, they are relative to the organ or site involved. The histological features are distinct. Surgical resection is curative in almost all cases, with only rare local recurrences. We report a case of symptomatic bilateral granular cell tumors arising in the posterior mediastinum.

Use of titanium wire in cervical spine fixation as a means to reduce MR artifacts.

MR imaging of the cervical spine is valuable for assessing traumatic injuries to the spinal cord and bony ligamentous structures. MR is also useful for detecting such long-term complications of spinal cord injury as syrinx, arachnoid cyst, cord adhesion, and persistent mechanical impingement on the spinal cord or spinal nerve roots. Treatment of cervical spine injuries that are mechanically unstable entails fixation and fusion. However, previous attempts at our institution to obtain clinically useful MR images of the cervical region after posterior wire fixation have failed because of image artifacts arising from ferromagnetic stainless steel wires. Use of biocompatible titanium wire for fixation allowed undistorted imaging of the spinal cord and spinal canal adjacent to the surgical fixation in a cadaver and in eight patients.

Acute cervical spine trauma: evaluation with 1.5-T MR imaging.

Twenty-one patients with acute neurologic deficits following cervical spine trauma were evaluated with magnetic resonance (MR) imaging (n = 21), computed tomography enhanced with intrathecal contrast material (CT myelography) (n = 18), myelography (n = 13), cervical spine radiography (n = 21), and intraoperative sonography (n = 7). MR imaging proved superior to other modalities in demonstrating parenchymal spinal cord injuries and cervical intervertebral disk herniation. Although both T1- and T2-weighted studies appear necessary to evaluate the anatomic relationship of the spinal cord, thecal space, intervertebral disks, and surrounding osseous and ligamentous structures, T2-weighted sequences were more sensitive than T1-weighted studies for detection of spinal cord injury. CT myelography was superior to MR imaging in demonstrating cervical spine fractures. In most cases, myelography revealed no information that was not apparent from both CT and MR imaging studies. Preliminary experience with MR imaging of acute cervical spine trauma suggests that it should be the study of choice in symptomatic patients who are otherwise clinically stable. CT may still be required in selected patients to evaluate complex fractures.

Complex fractures of the clivus: diagnosis with CT and clinical outcome in 11 patients.

During a 20-month period, fractures of the clivus occurring after craniocerebral trauma were diagnosed with computed tomography (CT) in 11 patients. Five patients had longitudinally oriented fractures; these were fatal in four patients due to either vertebral-basilar artery occlusion, brain stem trauma, or both. Six other patients had transversely oriented fractures that extended through the carotid canal and petrous temporal bone. While less frequently contributing directly to mortality, transverse fractures were also associated with cerebrospinal fluid leaks (two patients) and a cavernous sinus-carotid fistula (one patient). They were not as frequently associated with Horner syndrome or cranial nerve deficits as suggested in the current literature. This retrospective evaluation reveals two distinct injury patterns that demonstrate a difference in related morbidity and mortality.

Magnetic resonance imaging in neuronal ceroid lipofuscinosis.

Neuronal ceroid lipofuscinosis is a group of neurodegenerative disorders characterized by accumulation of lipofuscin and/or ceroid within the tissues of the body. These entities are manifest by visual, intellectual, and motor deterioration as well as recurrent seizures. Computed tomography has been shown to demonstrate changes of cerebral atrophy in more severely affected patients. Seven patients with neuronal ceroid lipofuscinosis were examined with both computed tomography and magnetic resonance imaging, and the results were correlated with the clinical severity of the disorder. Two less severely affected patients had normal results on computed tomography and magnetic resonance imaging studies. Varying degrees of cerebral atrophy were seen in the remaining five patients with both computed tomography and magnetic resonance imaging. Severity of atrophy correlated with the severity of disability in these patients. Abnormal white matter was seen in the two most severely affected patients only with magnetic resonance imaging. Although the findings in patients with neuronal ceroid lipofuscinosis were nonspecific, the increased sensitivity of magnetic resonance imaging for subtle white matter abnormalities over computed tomography may prove helpful in monitoring the progression of this rare disorder.

Pure thoracolumbar facet dislocation: clinical features and CT appearance.

The use of computed tomography (CT) in demonstrating pure dislocations of the thoracolumbar facets and in predicting the prognosis of this injury was evaluated and compared with radiography retrospectively. The records of 29 patients with pure thoracolumbar bilateral facet dislocation who were admitted to the trauma unit over a 4-year period were reviewed. Twenty-two patients (76%) had a complete neurologic loss that remained complete following immediate surgical stabilization; five (17%) had an incomplete neurologic loss, and two (7%) were normal neurologically. Plain radiographs of the spine, including anteroposterior and lateral views, documented the level and type of fracture but failed to depict the full extent of bony ad soft-tissue injuries. CT provided essential additional information, particularly regarding the status of the posterior elements of the vertebrae and the adequacy of the spinal canal. Pure thoracolumbar facet dislocations have a characteristic appearance on axial CT scans. Sagittal reformation through CT is essential in the evaluation of this type of spinal injury.

Intracranial gyriform calcification associated with subarachnoid fat.

Intracranial convolutional or gyriform calcification simulating Sturge-Weber syndrome has been described in association with bacterial and viral intracranial infection as well as irradiation and intrathecal methotrexate for central nervous system leukemia. Reported is a case of gyriform calcification caused by chemical meningitis secondary to subarachnoid fat from an epidermoid tumor.

Aneurysmal rupture during computed tomography scanning.

A unique case in which a berry aneurysm was observed to rupture during computed tomography scanning of the brain is reported. Two earlier case reports of aneurysmal rupture during computed tomography scanning are reviewed, followed by a discussion of possible mechanisms of rupture during contrast studies. Contrast medium infusion may have the potential to cause aneurysmal rupture by a direct anticoagulant effect, by affecting the endothelial membrane, by interacting with platelet release of vasoactive substances, by inducing vasodilation, by removing the protective arterial spasm, or by other unexplored mechanisms. The information to be gained by infusion of contrast medium in cases of aneurysmal rupture can be significant and the rarity of rerupture during contrast medium infusion does not appear to pose a significant risk in the vast majority of cases.

Cerebellar infarction in the superior cerebellar artery distribution.

Three patients with CT and angiographic documentation of cerebellar infarction in the superior cerebellar artery distribution had ataxic gait with little or no vertigo. Limb ataxia occurred in two patients. Transient chorea and signs of pontine infarction were also noted. CT demonstrated infarcts on the upper surface of a cerebellar hemisphere and/or vermis. Angiograms disclosed occlusion of the top of the basilar artery in two cases and distal superior cerebellar artery (SCA) branches in one. One patient later died after distal basilar artery occlusion; the others recovered.

Simultaneous rupture of two intracranial aneurysms: CT diagnosis.

A case of simultaneous rupture of two intracranial aneurysms is reported. This is a rare event, and we found no CT reports of such a case. This case points out that the usual assumption of a single aneurysm rupture in a patient with multiple aneurysms may be erroneous and difficult to diagnose angiographically, but may lend itself to CT diagnosis.

Arterio-colonic fistula during scintigraphic evaluation of gastrointestinal bleeding.

The use of scintigraphic imaging in the evaluation of gastrointestinal (GI) hemorrhage has been established recently as a screening procedure prior to anigography. We report an unusual and previously unreported cause of acute GI bleeding which illustrates several technical factors to be considered during scintigraphic evaluation of GI bleeding.

Lissencephaly: computed tomographic diagnosis.

Lissencephaly is a rare congenital condition with distinctive brain changes. Most of these changes were demonstrated on computed tomography, and include lack of cortical sulci and gyri; calcification in the region of paraphysis; wide, shallow sylvian fissures; colpocephaly; poor development of white matter; and persistent cavum septum pellucidum and cavum vergae.