Lacunar infarct during pallidotomy: case report.

A symptomatic lacunar infarct is an unusual complication which may develop during stereotactically guided pallidotomy using radiofrequency thermoablation. We describe a 54-year-old man with Parkinson's disease involving predominantly the right side, progressively deteriorating under medical management. He underwent stereotactically guided radiofrequency thermoablation of the posteroventral globus pallidus interna. Despite intraoperative microelectrode recording and stimulation, the patient developed right facial weakness and pronator drift during the procedure. MRI showed a small lacunar infarct in the left internal capsule, in addition to the appropriately placed ablative lesion. We discuss the potential mechanisms for this type of injury.

Interregional variation of longitudinal relaxation rates in human brain at 3.0 T: relation to estimated iron and water contents.

In a study of interregional variation of the longitudinal relaxation rate (R(1)) in human brain at 3 T, R(1) maps were acquired from 12 healthy adults using a multi-slice implementation of the T one by multiple readout pulses (TOMROP) sequence. Mean R(1) values were obtained from the prefrontal cortex (0.567 +/- 0.020 sec(-1)), caudate head (0.675 +/- 0.019 sec(-1)), putamen (0.749 +/- 0.023 sec(-1)), substantia nigra (0.873 +/- 0.037 sec(-1)), globus pallidus (0.960 +/- 0.034 sec(-1)), thalamus (0.822 +/- 0.027 sec(-1)), and frontal white matter (1.184 +/- 0.057 sec(-1)). For gray matter regions other than the thalamus, R(1) showed a strong correlation (r = 0.984, P < 0.0001) with estimated regional nonheme iron concentrations ([Fe]). These R(1) values also showed a strong correlation (r = 0.976, P < 0.0001) with estimates of 1/f(w) obtained from MRI relative proton density measurements, where f(w) represents tissue water content. When white matter is included in the consideration, 1/f(w) is a better predictor of R(1) than is [Fe]. An analysis based on the fast-exchange two-state model of longitudinal relaxation suggests that interregional differences in f(w) account for the majority of the variation of R(1) across gray matter regions. Magn Reson Med 45:71-79, 2001.

MR of CNS sarcoidosis: correlation of imaging features to clinical symptoms and response to treatment.

BACKGROUND AND PURPOSE: Sarcoidosis is an idiopathic systemic granulomatous disease, recognized in a patient when clinical and radiologic findings are confirmed by histopathologic analysis. The objective was to identify a relationship between MR imaging and clinical findings in CNS sarcoidosis. METHODS: The clinical charts of 461 patients with biopsy-proved sarcoidosis were reviewed retrospectively. Criteria for including patients in the study included those with symptoms referable to the CNS, excluding those with another explanation for their symptoms, those with headaches or other subjective complaints without accompanying objective findings, and those with peripheral neuropathy other than cranial nerve involvement or myopathy without CNS manifestations. Thirty-four of 38 patients whose conditions met the criteria for CNS sarcoidosis underwent a total of 82 MR examinations. The positive imaging findings were divided into categories as follows: pachymeningeal, leptomeningeal, nonenhancing brain parenchymal, enhancing brain parenchymal, cranial nerve, and spinal cord and nerve root involvement. Treatment response, clinical symptomatology, and any available histopathologic studies were analyzed with respect to imaging manifestations in each of the categories. RESULTS: Eighty-two percent of the patients with sarcoidosis with neurologic symptoms referable to the CNS had findings revealed by MR imaging. However, eight (40%) of 20 cranial nerve deficits seen at clinical examination of 13 patients were not seen at contrast-enhanced MR imaging, and 50% of the patients with symptoms referable to the pituitary axis had no abnormal findings on routine contrast-enhanced MR images. In contradistinction, 44% of 18 cranial nerves in nine patients with MR evidence of involvement had no symptoms referable to the involved cranial nerve. Clinical and radiologic deterioration occurred more commonly with leptomeningeal and enhancing brain parenchymal lesions. CONCLUSION: MR imaging can be used to confirm clinical suspicion and to show subclinical disease and the response of pathologic lesions to treatment.

MR imaging of human brain at 3.0 T: preliminary report on transverse relaxation rates and relation to estimated iron content.

PURPOSE: To determine the transverse relaxation rates R2 and R2' from several gray matter regions and from frontal cortical white matter in healthy human brains in vivo and to determine the relationship between relaxation rates and iron concentration [Fe]. MATERIALS AND METHODS: Six healthy adults aged 19-42 years underwent thin-section gradient-echo sampling of free induction decay and echo magnetic resonance (MR) imaging at 3.0 T. Imaging covered the mesencephalon and basal ganglia. RESULTS: Relaxation rates (mean +/- SD) were highest in globus pallidus (R2 = 25.8 seconds-1 +/- 1.1, R2' = 12.0 seconds-1 +/- 2.1) and lowest in prefrontal cortex (R2 = 14.4 seconds-1 +/- 1.8, R2' = 3.4 seconds-1 +/- 1.1). Frontal white matter measurements were as follows: R2 = 18.0 seconds-1 +/- 1.2 and R2' = 3.9 seconds-1 +/- 1.2. For gray matter, both R2 and R2' showed a strong correlation (r = 0.92, P < .001 and r = 0.90, P < .001, respectively) with [Fe]. Although the slopes of the regression lines for R2' versus [Fe] and for R2 versus [Fe] were similar, the iron-independent component of R2' (2.2 seconds-1 +/- 0.6), the value when [Fe] = 0, was much less than that of R2 (12.7 seconds-1 +/- 0.7). CONCLUSION: The small iron-independent component R2', as compared with that of R2, is consistent with the hypothesis that R2' has higher iron-related specificity.

Bilateral superior ophthalmic vein enlargement associated with diffuse cerebral swelling. Report of 11 cases.

Bilateral superior ophthalmic vein (SOV) enlargement has rarely been shown to occur in patients with septic and aseptic cavernous sinus thrombosis, Graves' disease due to obstruction of the SOV by enlarged extraocular muscles, or carotid-cavernous fistulas caused by retrograde flow. The authors describe 11 patients with bilateral SOV enlargement associated with cerebral swelling as detected by computerized tomography scanning. The bilaterally enlarged SOVs returned to a normal size following resolution of cerebral swelling and elevated intracranial pressure. To the authors' knowledge, this is the first report of bilateral SOV enlargement associated with diffuse cerebral swelling that subsequently resolved after treatment of the cerebral edema. The authors believe that the bilateral SOV enlargement was caused by mechanical cavernous sinus venous stagnation due to cerebral swelling, a syndrome that occurs more commonly than currently appreciated.

Cystic papillary adenocarcinoma of the submandibular gland in a child.

A 12-year-old boy reported that a mass in his left jaw had been growing slowly for 8 months. Axial and coronal contrast-enhanced spiral CT showed a 5-cm cystic mass within an enhancing, mildly enlarged submandibular gland. Excisional biopsy revealed a cystic papillary adenocarcinoma of the left submandibular gland, very rare in children.

Efficacy of gadolinium administration in magnetic resonance imaging screening of patients with complex partial seizures and results of a normal neurologic examination.

RATIONALE AND OBJECTIVES: Magnetic resonance imaging has become a standard screening tool in the evaluation of patients with complex partial seizures. This study prospectively addresses the efficacy, if any, of routinely adding gadolinium-enhanced images to routine T2-weighted images in patients with a normal neurologic examination. METHODS: One hundred consecutive patients with electroencephalogram and clinical evidence of complex partial seizures and no other neurologic abnormalities were examined prospectively with axial and coronal T2-weighted spin-echo images, followed by axial and coronal gadolinium-enhanced T1-weighted scans. RESULTS: The scans in 73 patients were interpreted as normal, 14 had nonspecific white matter lesions, 5 had asymmetry of the temporal horns, and 2 had asymmetric signal intensity in the temporal lobes, and the scans in 6 showed abnormal gadolinium enhancement. Of the lesions in the six patients whose scans showed abnormal enhancement, four were seen well on the T2-weighted images. Of the remaining two, one was a small cerebellar venous angioma, and the other, a probable tiny convexity meningioma. One temporal lobe glioma seen on the T2 scans did not enhance with gadolinium. CONCLUSIONS: Routine administration of gadolinium does not appear to be of benefit in imaging patients with complex partial seizures who are otherwise neurologically normal.

MR demonstration of Wegener granulomatosis of the infundibulum, a cause of diabetes insipidus.

We report a case of Wegener granulomatosis causing hyperprolactinemia followed by central diabetes insipidus. The initial T1-weighted MR image showed an isointense heterogeneous sellar mass. After the onset of diabetes insipidus, repeat sagittal and postcontrast T1-weighted images showed marked infundibular thickening, enlargement of the sellar mass, and enhancement of both the infundibulum and hypothalamus. Follow-up MR after marked clinical response to corticosteroids showed nearly complete resolution of the aforementioned abnormalities.

Normal imaging anatomy of the suprasellar cistern and floor of the third ventricle.

This article discusses the gross, functional, and imaging anatomy of the suprasellar cistern and its contents as well as the structures that form its borders, among the most important being the floor of the third ventricle and associated structures. Specific structures discussed include the optic chiasm and optic tracts, the anterior third ventricle, the tuber cinereum, the pituitary stalk (infundibulum), the choroidal fissure, the lamina terminalis, the gyrus rectus, the uncus, and the cerebral peduncles.

Persistent trigeminal artery detected with standard MRI.

The trigeminal artery is the most common of the primitive carotid-basilar anastomoses to persist into adulthood. Prior to the introduction of MRI, the diagnosis of persistent trigeminal artery (PTA) could only be made at cerebral angiography. This study compares angiography and standard brain MRI in 11 cases of PTA. Nine of the 11 PTAs were identified with MRI. Axial imaging gave the best definition of the course of the PTA.

Analysis of the evolution of focal cerebral ischemia in the rat using the eigenimage filter.

The eigenimage filter was used to evaluate the results of a MRI study of cerebral ischemia in a rat model. This linear filter segments a desired feature in an image sequence from other features which may interfere with its observation. The animals were imaged temporally, after occlusion of the middle cerebral artery, to investigate the evolution of the ischemic process. The temporal evolution of ischemia was evaluated by analysis of the "eigenimages," calculated T2 and T1 map images, and images for the angles between signature vectors defined in the eigenimage technique. The eigenimages and angle map images demonstrated an improved visibility of the lesion at all time points, as compared to the original images and T2 and T1 map images. The eigenimages also demonstrated signal intensity changes within the area of ischemia. These changes are speculated to be related to variations in local cerebral blood flow resulting in varying degrees of tissue damage. The eigenimage intensities and the angles between signature vectors demonstrated time-related changes similar to the T2 and T1 values. Since the eigenimage filter and angle calculations are not dependent upon physical models (like T2 and T1), and the errors associated with these models, they may be preferable as methods for tissue characterization.

Anomalous rib presenting as cervical myelopathy: a previously unreported variant of Klippel-Feil syndrome. Case report.

A patient is reported with an anomalous rib that caused compression of the cervical spinal cord and presented with cervical myelopathy. This appears to be the first reported instance of this particular anomaly. The clinicoanatomical aspects of this case are discussed.

The MR appearance of endovascular embolic agents in vitro with clinical correlation.

A spectrum of embolic agents including PVA, avitene, gelfoam, ethanol, IBCA, silicone microspheres, metal and platinum coils, and balloons containing contrast of HEMA were imaged in vitro at 0.3 Tesla using spin echo, gradient echo, and inversion recovery sequences. Signal intensities associated with these agents and changes created by addition of blood are presented. The in vitro model is also correlated with clinical MR material. Recognition of embolic materials is important to avoid confusion with persistent flow void, hemorrhage, or thrombus.

Current status of magnetic resonance imaging of the orbit.

MR plays an important role in evaluating pathologic conditions that affect the orbit. MR appears to be superior to ultrasound and computed tomography in evaluation of intraocular tumors and fluid collections. In evaluation of noncalcified intraorbital tumors, MR can provide more information regarding orbital apex involvement and intracranial extension. Inflammatory lesions, particularly orbital pseudotumor, can be differentiated from metastatic disease based on differences in signal intensity providing greater specificity than CT. Specific prognostic information may be obtained regarding potentially treatable cases of Graves' disease. Using MR, vascular lesions of the orbit can be assessed for patency or thrombosis without use of intravenous contrast. Demonstration of secondary extension by para-orbital sinus tumors by MR is often helpful in evaluating involvement of the soft tissue structures of the orbit. Potential applications in evaluation of orbital trauma include characterization of orbital hematomas and orbital blow-out fractures.

Magnetic resonance demonstration of vertebral artery dissection. Report of two cases.

Vertebral artery dissection may be spontaneous or related to some traumatic event. Diagnosis has usually been made by angiography, an invasive procedure with certain well-known risks. The authors describe the magnetic resonance (MR) appearance (both on conventional spin-echo and on gradient refocused "flow" sequences) in two patients with vertebral artery dissection confirmed by angiography. It is proposed that the less invasive MR imaging might be the imaging modality of choice for initial evaluation of suspected vertebral artery dissection.

Extracranial lesions of the head and neck: preliminary experience with Gd-DTPA-enhanced MR imaging.

The authors report initial experience with magnetic resonance imaging enhanced with gadolinium diethylenetriaminepentaacetic acid (DTPA) in 27 patients with various extracranial lesions of the head and neck. Unenhanced T1- and T2-weighted images were compared with T1-weighted images obtained 3-30 minutes after Gd-DTPA administration. Overall, compared with precontrast T1- and T2-weighted images, Gd-DTPA improved the visibility of lesions in 11 and five of 27 patients, respectively. Gd-DTPA particularly improved the conspicuity of tumors of the nasal cavity and paranasal sinuses and tumors having perineural or intracranial extension. Gd-DTPA-enhanced images were equivalent to precontrast T1- and T2-weighted images in five and 13 patients, respectively, and inferior to them in nine and eight patients, respectively. Mixed results were obtained in two patients and one patient when Gd-DTPA-enhanced images were compared with T1- and T2-weighted images, respectively. The authors conclude that Gd-DTPA has definite but limited uses in extracranial head and neck pathologic conditions and that more research is needed to evaluate particular applications.

Radiological assessment of dysphagia with endoscopic correlation.

Four hundred fifty consecutive patients with dysphagia were evaluated radiologically over a 14-month period; 127 of these (28.2%) were also examined endoscopically. The most common abnormality seen was dysmotility (34%), followed by hiatal hernia, benign stricture, and esophagitis. Correlation with endoscopy was generally good. Radiologic study demonstrated all cases of esophageal malignancy; radiologic/endoscopic correlation was also strong in patients with moderate or severe esophagitis, though the radiologist had some difficulty detecting mild inflammation. Endoscopy failed to demonstrate some benign strictures. Radiologic study was relatively accurate in detecting significant organic disease; most motility disorders were not detected by endoscopy. For these reasons, as well as lower cost, increased convenience, and patient comfort, radiologic assessment is recommended as the primary method of evaluating patients with dysphagia.