Choroid plexus metastasis of lung carcinoma--case report.

Metastatic tumors in the choroid plexus are generally considered to be very rare. The authors present a case of lung large cell carcinoma with a single metastatic tumor in the choroid plexus of the lateral ventricle trigone. Precontrast computed tomographic (CT) scans showed an isodensity mass with extensive peritumoral edema, which was considerably enhanced on the postcontrast CT scans. Magnetic resonance (MR) images demonstrated the mass as a low-intensity area on the T1-weighted image and an iso-intensity area on the T2-weighted image. The tumor was clearly differentiated from the peritumoral edema by both CT and MR imaging. The diagnosis was confirmed by surgery.     

Clinicopathological study of multiple gliomas--report of three cases.

Three cases of multiple gliomas with postmortem findings including a rare case of multicentric glioma are presented. A 59-year-old female was hospitalized with decreased mental activity and gait disturbance. Computed tomographic (CT) scans and magnetic resonance (MR) images showed two independent mass lesions in the left frontal and the right temporal lobes, shown by postmortem to have no communication. Histologically, they were a gemistocytic astrocytoma and an anaplastic astrocytoma, respectively. Therefore, multicentric glioma was diagnosed. A 66-year-old male was admitted with slow mentation and gait disturbance. CT scans and MR images demonstrated two mass lesions; one overriding the bilateral frontal lobes through the corpus callosum and the other in the left temporal lobe. Postmortem examination showed that both lesions were glioblastoma and the left temporal tumor was accompanied by subarachnoid dissemination. A 29-year-old male was hospitalized with gustatory hallucination and convulsions of the right upper extremity. CT scans revealed two mass lesions in the right frontal and the left temporal lobes. MR images demonstrated communication between the two lesions through the corpus callosum. The left temporal tumor developed into the occipital lobe and another new lesion appeared in the right temporal lobe despite chemotherapy and irradiation. Postmortem examination revealed communication between the three masses through the corpus callosum. Histologically, all three tumors were glioblastoma. Multicentric gliomas have been reported at various incidences from 2.3 to 9.1%. However, multicentric gliomas with multiple tumors of different histologies are very rare and only 16 cases have been reported. MR imaging is more valuable than CT scanning to detect communication between two or more lesions.     

Multicentric intracranial fibrous xanthoma--case report.

Intracranial fibrous xanthoma is extremely rare; only 11 cases have been reported so far. The authors report a case of multicentric intracranial fibrous xanthoma. Precontrast computed tomographic (CT) scans revealed a left frontal subdural mass, which had previously been diagnosed as a chronic subdural hematoma at another hospital. However, operation disclosed no hematoma but a granulomatous tumor. The biopsied specimen was histologically diagnosed as fibrous xanthoma. Postoperative postcontrast CT scans showed intense homogeneous enhancement at the clival and the left frontal regions, both of which appeared as iso- to low-intensity areas on T1-weighted magnetic resonance (MR) images and as low-intensity areas on T2-weighted MR images. She gradually recovered by conservative treatment but suddenly died of cerebral infarction. Autopsy revealed fibrous xanthomas in the left frontal and the clival regions. This is the first report of the use of MR imaging for intracranial fibrous xanthoma, and its features differ from those of common intracranial parenchymal tumors, MR imaging can be helpful in the diagnosis of this tumor.     

Neuroimaging of cerebellar liponeurocytoma. Case report.

Cerebellar liponeurocytoma is a newly recognized, rare clinicopathological entity. It manifests with posterior fossa symptoms in adults and is characterized histopathologically by advanced neuronal and focal lipomatous differentiation with a low level of mitotic activity. The authors analyzed the computerized tomography (CT) and magnetic resonance (MR) imaging findings in two patients with histopathologically proven cerebellar liponeurocytomas and review the literature. Cerebellar liponeurocytoma may be suspected on the basis of neuroimaging findings that demonstrate an intraaxial neoplasm with the propensity for exophytic growth into the adjacent subarachnoid spaces. On CT scans, the tumor commonly presents as a hypointense mass with intermingled areas exhibiting the attenuation values of fatty tissue. On T1-weighted MR images, the tumor is hypointense with scattered foci of hyperintense signal and displays moderate contrast enhancement. On T1-weighted MR images, the tumor is slightly hyperintense to cortex, and edema is usually absent. Areas of fat density as assessed on CT scans and of T1 hyperintensity seen on MR images help to distinguish this rare neoplasm from the more common adult medulloblastomas or ependymomas. The available follow-up data indicate a favorable clinical prognosis; therefore, knowledge and precise characterization of this tumor is important to avoid unnecessary adjuvant radio- or chemotherapy.     

Computed tomography and magnetic resonance imaging of nonhemorrhagic, metastatic melanoma of the brain--case report.

Malignant melanoma frequently metastasizes to the central nervous system. Characteristic features of such lesions are increased density on computed tomography (CT) and shortening of the T1 and T2 on magnetic resonance (MR) imaging. Intratumoral hemorrhage, rather than melanin, is considered to be mainly responsible for these unique radiological features. The authors report a case involving a nonhemorrhagic, metastatic intracerebral melanoma. CT revealed a high-density mass, and MR imaging demonstrated a hyperintense mass both on T1- and T2-weighted images. These observations suggest that melanin is in fact a major determinant of the increased density on CT scans and the high signal intensity on T1-weighted MR images. On T2-weighted images, the paramagnetic effect appears to vary according to the melanin content.     

Positron emission tomography imaging-directed stereotactic neurosurgery.

The diagnostic yield of stereotactic biopsies depends upon safely sampling the most representative regions of masses. Potentially, localization information presently available from CT and MR scans might be improved by considering regional levels of cerebral metabolism by PET. In 10 selected stereotactic biopsies of intracranial mass lesions, PET scans were obtained using the Siemens CTI system; the Kelly-Goerss Compass system was used as the stereotactic development platform. PET-[18F]-fluorodeoxyglucose (FDG) images provided clinically significant information by appropriately directing biopsy efforts when CT and MRI was inconclusive or misleading. PET-FDG images can be successfully incorporated into routine image-directed stereotactic surgery.     

Radiological imaging in primary parotid malignancy.

In a retrospective analysis of the preoperative imaging of patients presenting with primary malignant parotid disease, all relevant images were collected and reviewed by two experienced head and neck radiologists, blinded to the diagnosis. Forty-two patients (25 male, 17 female), median age 67.5 years (range 15-86), were included in the study of which 32 had undergone CT scanning, nine MR and three ultrasound. Forty tumours (93%) were correctly diagnosed as malignant when compared with histology. The two false negatives arose in a patient who had received an ultrasound scan only and in a patient with lymphoma, whose CT scan was reported as a pleomorphic adenoma. Neither had undergone prior radiotherapy. A poorly defined tumour boundary was the most consistent observation for both MR and CT images for the malignant tumours examined. Local infiltration was correctly correlated with pathological findings in eight of the nine MR scans, however, CT proved less reliable, correct in 14 of 24 cases (p=0.01).No correlation was identified between any of the imaging features examined and the final histological diagnosis. A poorly defined tumour boundary with evidence of local invasion was the best indicator of malignancy and was reported more frequently from MR scans than from CT. Imaging alone, however, proved unreliable in the prediction of final histological diagnosis or grade of tumour.     

A frameless, armless navigational system for computer-assisted neurosurgery. Technical note

A computer-assisted neurosurgical navigational system has been developed which displays intraoperative manipulation on the preoperative computerized tomography (CT) scans or magnetic resonance (MR) images. The system consists of a three-dimensional digitizer, a personal computer, and an image-processing unit. Utilizing recently developed magnetic field modulation technology, the three-dimensional digitizer determines the spatial position and orientation angles of the resin probe, triangle-shaped pointer, or suction tube with a small attached magnetic field sensor. Four fiducial markers on the scalp were used to translate the spatial data of the probe onto the preoperative CT scans or MR images of the patient. With this frameless, armless navigational system, CT or MR-imaging stereotaxy can be applied to conventional open neurosurgery without limiting the operative field or interfering with the surgical procedures.     

Delayed postcontrast CT and MR imaging of chondroid chordoma--case report.

A rare case of intracranial primary chondroid chordoma is reported with special reference to neuroradiological findings. A precontrast computed tomographic (CT) scan revealed an isodense mass with multiple flecks in the right cerebellopontine region. A postcontrast CT scan showed slight ring enhancement. A delayed postcontrast CT scan demonstrated marked homogeneous enhancement extending from the middle cranial fossa to the cerebellopontine region on the right. Magnetic resonance (MR) imaging demonstrated a well-defined lesion as a high-intensity mass on T2-weighted image and a low-intensity mass on T1-weighted image. A MR image 5 minutes after gadolinium-diethylenetriaminepenta-acetic acid administration showed heterogeneous enhancement. A MR image 30 minutes after the contrast administration showed more marked, homogeneous enhancement. Such delayed postcontrast CT and MR imaging are useful in the differentiation of chondroid chordoma from classical chordoma.     

Stereotaxic surgery with a magnetic resonance- and computerized tomography-compatible system

Modern stereotaxic surgery is dependent upon compatible advanced imaging tools, including computerized tomography (CT) scanning and magnetic resonance (MR) imaging. The authors describe three cases in which the patients underwent stereotaxic surgery for mass lesions identified by both MR imaging and CT scans. Identical target coordinates were defined by both techniques, and accuracy was confirmed by intraoperative CT. In comparison to stereotaxic CT, MR provided superior contrast resolution, allowed direct multiplanar imaging and target determination, and permitted accurate correlation of the image with histological features. The operative set-up and technique are described. Stereotaxic surgery with MR imaging may permit more accurate histopathological definition of tumor margins and ultimately lead to better dosimetry for therapeutic procedures such as interstitial brachytherapy.     

Radiation-induced bilateral cystic frontal lobe necroses demonstrating a fluid-blood level--case report.

A 41-year-old male developed radiation-induced bilateral cystic frontal lobe necroses after irradiation for an olfactory neuroblastoma. Computed tomography (CT) and magnetic resonance (MR) imaging revealed the lesions, one containing a fluid-blood level on CT scans and niveau formation on MR images. It was proved to be a coagulated hematoma within the cyst at surgery. Such a fluid-blood level in a radiation-induced cyst has never been reported, although hemorrhage frequently accompanies delayed radiation necrosis. Positron emission tomography with multiple tracers may be useful in differentiating cerebral radiation necrosis from tumor recurrence, because of absence of abnormal tracer accumulation.     

Spontaneous retroclival hematoma presenting as a thunderclap headache. Case report

An excruciating headache of instantaneous onset, or thunderclap headache, may be caused by a variety of serious disorders, including aneurysmal subarachnoid hemorrhage, cerebral venous sinus thrombosis, pituitary apoplexy, and carotid artery or vertebral artery dissection. The authors describe a patient with this type of headache who was found to have a spontaneous retroclival hematoma. A 49-year-old woman experienced an instantaneous excruciating headache. Results of computerized tomography (CT) scans of the head were normal, but on examination of the cerebrospinal fluid xanthochromia was found. Magnetic resonance (MR) imaging of the cervical spine revealed a retroclival hematoma. Three cerebral angiographic studies did not reveal the source of the hemorrhage and a repeated MR image demonstrated resolution of the hematoma. The patient made an uneventful recovery. Spontaneous retroclival hematoma is an exceedingly rare type of intracranial hemorrhage and may be associated with normal findings on CT scans. Spontaneous retroclival hematoma should be included in the differential diagnosis of thunderclap headache.     

Magnetic resonance imaging of the sella turcica and parasellar region. A clinical-radiographic evaluation with computed tomography

Thirty-one magnetic resonance (MR) scans and computed tomography (CT) scans were obtained on 25 patients in whom lesions involving the sella turcica or parasellar region were clinically suspected. Surgical pathologic studies were available in 19 cases. Twenty-two of the MR scans were of diagnostic value equivalent to that of the corresponding CT studies. In two small meningiomas, an empty sella, and a sphenoid-middle fossa tumor, MR technology failed to delineate the pathologic process adequately. In the remaining five patients, MR either more convincingly demonstrated the pathologic anatomy or yielded diagnostic information not present in the CT study. In view of the absence of ionizing radiation, high degree of tissue contrast and spatial resolution, and multiplanar capability, magnetic resonance scanning will probably become the initial imaging modality of choice in patients suspected of harboring sellar and parasellar tumors.     

MR imaging as predictor of delayed posttraumatic cerebral hemorrhage

The occurrence of delayed traumatic intracerebral hemorrhage or hematomas was predicted in four patients by T2-weighted magnetic resonance (MR) imaging. From June, 1986, through February, 1987, 42 patients with head injury were admitted to the Neurosurgical Service of the Seirei Mikatabara General Hospital. Cerebral contusion was suspected in six of these patients. Although the initial computerized tomography (CT) scans showed no cerebral parenchymal lesion, the initial symptoms were more serious than might have been expected from the initial CT findings and/or because their initial CT scans showed intracranial extracerebral hemorrhage. In all six, the initial CT scans were obtained within 2 hours after the injury and were followed by MR imaging. In four patients, T2-weighted MR images revealed areas of increased signal intensity in the cerebral parenchyma, where hemorrhagic changes were subsequently demonstrated by follow-up CT scans. In the remaining two, T2-weighted MR images showed no parenchymal lesion and subsequent CT scans confirmed the absence of hemorrhagic change; these two patients were discharged from the hospital without neurological deficits. It is concluded that MR imaging is useful in predicting delayed hemorrhages.     

A case of intracranial osteochondroma: its MR images

A 15-year-old boy was referred to our department due to left abducens palsy and trigeminal neuralgia. CT scans that had been taken fourteen months before this referral failed to disclose any abnormality. CT scans taken on admission, however, demonstrated an irregular calcified lesion in the left parasellar region. This implied that some ossifying process had been progressing during these fourteen months. MR images clearly demonstrated tumor contour and it was shown that high and low intensity spots were evenly scattered within the tumor. Consequently, tumor appearances in MR images were totally different from those in CT scans. MR images were useful in investigating contour and extension of osteochondroma, but CT scans were necessary to locate calcified foci within the tumor.     

Computed Tomography and Magnetic Resonance Imaging of Mild Head Injury – Is it Appropriate to Classify Patients with Glasgow Coma Scale Score of 13 to 15 as “Mild Injury”?

Summary. Summary. Objective: The purpose of this study is to examine the relation between Glasgow Coma Scale (GCS) score and findings on computed tomography (CT) and magnetic resonance (MR) imaging of patients with mild head injury presenting GCS scores between 13 and 15. Methods: Data were collected from all consecutive patients with mild head injury who were referred to our hospital between July 1 and October 31, 1999. All patients were recommended to undergo CT and MR imaging examinations. Patients younger than 14 years of age were excluded. Results: Ninety patients were recruited into this study. CT scans were obtained in 88 patients and MR imaging were obtained in 65 patients. Of these 90 patients, 2 patients scored 13 points, 5 scored 14 points and 83 (92.2%) 15 points. Patients with GCS score of 13 points demonstrated parenchymal lesions on both CT and MR imaging. Those with 14 points revealed absence of parenchymal abnormality on CT, but presence of parenchymal lesions on MR imaging. Patients in advanced age (chi square test, p<0.0001), and those with amnesia (p=0005, not significant), although scoring 15 points, revealed a tendency to abnormal intracranial lesions on CT scans. Conclusion: It is doubtful whether patients with GCS score 13 should be included in the mild head injury category, due to obvious brain damage on CT scans. MR imaging should be performed on patients with GCS score 14, since the parenchymal lesions are not clearly demonstrated on CT scans. Even if patients scored GCS 15, patients with amnesia or of advanced age should undergo CT scans at minimum, and MR imaging when available.     

Intrathecal and intraperitoneal germinomas occurring 20 years after total removal of a pineal teratoma. Case report

In 1980, a 10-year-old boy was admitted to the authors' hospital with consciousness disturbance and vomiting. Computerized tomography (CT) scans revealed a pineal mass lesion and hydrocephalus. The tumor was totally removed and a ventriculoperitoneal (VP) shunt was inserted. Histological investigation of a surgical specimen revealed that it was a teratoma. Five years later, the patient was readmitted to the same institution with polyuria. Magnetic resonance (MR) imaging revealed a mass lesion in the suprasellar region. The patient received systemic chemotherapy, and the tumor disappeared; however, 2 years after the chemotherapy, MR imaging demonstrated a right lateral ventricular mass. The tumor was totally resected, and histopathological investigation revealed a teratocarcinoma. Three years after the chemotherapy, CT scanning revealed suprasellar and right lateral ventricular tumor recurrences, for which the patient received irradiation and chemotherapy. The tumors disappeared and the patient achieved complete remission that lasted longer than 10 years. On January 25, 2000, however, he noticed hip pain. Lumbar MR imaging demonstrated a spinal tumor below L-4 and also an abdominal tumor. The abdominal tumor was totally removed, and the histological findings identified it as a germinoma. The patient received systemic chemotherapy and the tumor disappeared completely. The authors believe that the suprasellar tumor was a metachronous germinoma and that it had metastasized through the intrathecal route and the VP shunt.     

Neurosyphilis manifesting as a focal mass lesion: computed tomographic and magnetic resonance imaging features--case report.

The computed tomographic (CT) and magnetic resonance (MR) imaging findings in a middle-aged male with cerebral syphilis are described. He presented with convulsive seizures and focal neurological deficits. A CT scan revealed a slightly enhanced, low-density mass in the left parieto-occipital region. MR imaging showed low intensity on T1-weighted images and high intensity on T2-weighted images. He was initially diagnosed as having a low-grade glioma. However, intraoperative histological examination of a small surgical specimen revealed no tumor cells but heavy infiltration of inflammatory cells in the meninges and cerebral parenchyma. Immunostaining for Treponema organisms by the peroxidase-antiperoxidase method was positive. Although the clinical and radiological findings are nonspecific, neurosyphilis should be considered in any patient in whom a nonspecific mass lesion is demonstrated by CT and MR imaging.     

Comparative evaluation of intracranial epidermoid tumors with computed tomography and magnetic resonance imaging

The diagnosis of intracranial epidermoid tumors with computed tomography (CT) is often difficult because of indistinct margins, close proximity to the skull base, and a density similar to that of cerebrospinal fluid (CSF). Recent experience with six histologically confirmed epidermoid tumors served to emphasize the value of magnetic resonance (MR) imaging in studying these lesions. MR images were obtained using varying spin echo and inversion recovery techniques with a 0.5-tesla superconducting magnet. CT with and without enhancement had been performed in each case. In Case 1, CT showed an ill-defined left cerebellopontine angle hypodensity. MR imaging clearly showed the presence of abnormal tissue at that location. Case 2 showed a CSF density mass in the right upper posterior fossa. MR imaging of that area showed a variegated signal of a mass extending supratentorially. CT of Case 3 showed a left medial middle fossa hypodensity with an enhancing rim. MR imaging showed a clearly extraaxial mass in that location. In Case 4, a diffuse cerebellar hemispheric hypodensity was observed on CT and was clearly demarcated by MR studies. A huge lesion, thought initially to be an arachnoid cyst on CT of Case 5, was seen on MR imaging to be a large, extraventricular mass displacing the temporal lobe. Finally, CT in Case 6 was suggestive of a poorly demarcated right cerebellopontine angle lesion, which was seen on MR images to be extraaxial, displacing the brain stem. Various MR images more clearly demonstrate the extent of abnormal tissue than CT of epidermoid tumors.(ABSTRACT TRUNCATED AT 250 WORDS)     

Unilateral opacification of paranasal sinus CT scans.

OBJECTIVES: The aim of study was to describe the histopathology in patients with unilateral sinus opacification and to identify variables that may predict neoplastic pathology. STUDY DESIGN: A retrospective review of paranasal sinus CT scans performed between 2000 and 2003 was conducted to identify patients with unilateral sinus opacification. RESULTS: Twenty-eight of 1118 CT scans showed unilateral sinus opacification. Twelve patients had neoplastic disease, 13 had inflammatory disease. Nasal discharge was more common in inflammatory than neoplastic disease (P = 0.009). A polyp or mass lesion was more common on nasendoscopy in neoplastic than inflammatory disease (P = 0.01). Bony erosion was only identified in malignant disease. CONCLUSION: A wide variety of pathologies present with unilateral sinus opacification on CT scanning. In our series, neoplastic disease was more associated with a visible polyp or mass lesion and less with nasal discharge. Bony erosion on CT scan was only seen in malignant disease. Histologic confirmation remains obligatory for diagnosis.