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C L Truwit

Publications and source records attributed to C L Truwit.

At least 19 recordsLinked to original sources
PubMed2006

Reversible findings of restricted diffusion in 5-fluorouracil neurotoxicity.

A 35-year-old woman presented with neurotoxicity correlated to an i.v. regimen of 5-fluorouracil as episodes of acute confusional state and abnormalities of symmetrically restricted diffusion in the periventricular white matter and corpus callosum. On discontinuing the medication, the areas of severely restricted diffusion had entirely resolved, with minimal residual T2 signal abnormality. In this case, immediate discontinuation of the chemotherapeutic agent apparently reversed the patient's symptoms and findings on MRI. The scant information available in the published literature regarding this phenomenon is reviewed with regard to 5-fluorouracil.

Adult↗
PubMed2004

CT perfusion imaging in the management of posterior reversible encephalopathy.

A 13-year-old girl with a renal transplant presented with hypertension and seizures. CT and MRI demonstrated typical bilateral parietal, occipital and posterior frontal cortical and subcortical edema, thought to represent posterior reversible encephalopathy syndrome. The cause was presumed to be hypertension. Antihypertensive therapy was started, lowering of the blood pressure in the range of 110-120 mmHg systolic. However, stable xenon (Xe) CT perfusion imaging revealed ischemia within the left parietal occipital region. The antihypertensive was adjusted which increased both the systolic and diastolic blood pressure by 31 mm Hg. The patient was re-imaged with Xe CT and was found to have resolution of the ischemic changes within the left parietal occipital region. In this report, we present a case in which stable Xe CT was used to monitor the degree of cerebral perfusion and guide titration of antihypertensive therapy. Such brain perfusion monitoring may have helped to prevent infarction of our patient.

Adolescent↗
PubMed2004

A retained neurointerventional microcatheter fragment in the anterior communicating artery aneurysm in multi-slice computed tomography angiography.

We present a case of multi-slice computed tomography angiography of a 60-year-old patient with a retained fragment of microcatheter within an anterior communicating artery (AcomA) aneurysm. This is a rare complication of Guglielmi detachable coil embolization. After an unsuccessful embolization procedure, the patient underwent surgery. During clipping of an AcomA aneurysm, the microcatheter traveled up the pericallosal branch of the right anterior cerebral artery. Subsequently, the microcatheter fragment did not prevent normal blood flow through the artery, and the patient has been doing well without neurological sequelae.

Anterior Cerebral Artery↗
PubMed2004

Intracranial metastasis via transplacental (vertical) transmission of maternal small cell lung cancer to fetus: CT and MRI findings.

We present the computed tomography (CT) and magnetic resonance imaging (MRI) findings of brain metastases in an unusual case of a premature, 33-week gestational age neonate who was emergently delivered from a mother suspected of having lung cancer according to imaging performed during the third trimester of pregnancy. Owing to the presence of placental metastases noted after delivery, the fetus had initial screening with brain MRI and chest/abdomen CT as well as serial screening imaging studies during the first 5 months of life, all of which were apparently normal. However, serial examinations eventually revealed a cerebellar lesion that significantly improved after chemotherapy but recurred and enlarged within a few months. This lesion was later confirmed to be metastasis by subsequent biopsy and resection. More metastatic lesions were identified in the frontal and temporal lobes on follow-up MRI. In the setting of aggressive maternal malignancy (without known fetal primary malignancy) an intracranial mass can, on the exceedingly rare occasion, result from maternal high-grade malignancy and the neuroradiologist should be alerted to this phenomenon.

Adult↗
PubMed2004

Multi-slice computed tomography angiography in the detection of residual or recurrent cerebral aneurysms after surgical clipping.

PURPOSE: To assess the diagnostic accuracy of multi-slice computed tomography (MSCT) angiography compared to digital subtraction angiography (DSA) in detecting residual or recurrent aneurysms in patients undergoing aneurysm clipping surgery. MATERIAL AND METHODS: Eight patients with nine aneurysms who had both MSCTA and DSA were included in the study. Two independent experienced neuroradiologists evaluated the examinations. RESULTS: Accuracy, sensitivity, and specificity of detecting residual or recurrent aneurysms on MSCTA were 0.80, 0.60, and 1.00, respectively. Positive and negative predictive values were 1.00 and 0.71, respectively. CONCLUSION: MSCTA is a promising technique for evaluating residual or recurrent aneurysms in patients undergoing surgical treatment of aneurysm with titanium clips.

Adult↗
PubMed2003

The roles of functional MRI in MR-guided neurosurgery in a combined 1.5 Tesla MR-operating room.

BACKGROUND AND PURPOSE: During MR-guided neurosurgical procedures performed in a combined 1.5 Tesla MR-operating room (MR-OR), we have successfully implemented and validated a functional MRI (fMRI) scheme for efficiently localizing eloquent functional areas and assessing their proximity to a lesion volume immediately prior to the craniotomy. METHODS: The fMRI examination consists of a dynamical blood oxygenation level dependent (BOLD) MR imaging technique and a task paradigm that is designed to activate the brain area of interest. The functional imaging technique was based on gradient-echo (GE) echo-planar imaging (EPI) (TR/TE = 2000-3000/40-50 msec). The motor task paradigm involves a periodic movement task, such as alternating between thumb and the other four fingers as a finger-tapping task, while the language involved a covert repeat of a series of words given as a task stimulus. While patient is performing the task, a dynamical fMRI was performed concurrently covering the volume of interest every 2 or 3 sec. Also, we have used a temporal series averaging (TSA) method for correcting the background drift in the raw fMRI signal, and developed a scheme for presenting fMRI results to neurosurgeons in an intuitive 3-dimensional volume-rendered display format. RESULTS: By using the fMRI scheme, we have successfully performed sixteen fMRI examinations immediately prior to neurosurgery in the combined MR-OR on the same surgical table to localize various eloquent functional areas of interests. TSA was successful in reducing the background drift in the fMRI time course data, and the 3-dimensional volume-rendered display was proven effective in presenting the resulting brain activations to neurosurgeons. More importantly, in three representative cases (one biopsy and two tumor resections) presented, the information provided by fMRI have indeed contributed significantly in making the optimal surgical decisions prior to craniotomy. CONCLUSIONS: Intra-operative fMRI can be an indispensable tool for determining the location of a neighboring eloquent functional area of concern in reference to a targeted lesion. Information provided by fMRI has helped in improving the outcome and clinician confidence of all surgeries performed.

Adolescent↗
PubMed2003

Costs and benefits of intraoperative MR-guided brain tumor resection.

We retrospectively compared the costs and benefits of brain tumor resection in the conventional operating room (cOR) with the interventional magnetic resonance (iMR) suite from 1993-1998. Comparisons were made for adults (diagnosis-related group (DRG) 001) and children (DRG 003) for length of stay (LOS), hospital charges and payments, hospital total direct and indirect costs, readmission rates, repeat resection (RR) interval, and net health outcome. Statistical analysis was with ANOVA, Dunnett's, and Bonferroni tests. For DRG 001, iMR LOS (3.7 days (d)) was 54.9% shorter than for cOR (8.2 d) for first resections (FR) (P < 0.001) and RR (6.0 vs. 8.7 d (31.0%), P < 0.05). IMR hospital charges were 12.2% lower ($4063) for FR and 4.1% lower ($922) for RR than for cOR. Total iMR hospital costs were 14.4% lower ($3415) than for cOR for FR and 3.3% lower ($723) than costs for RR. Cost-to-charge ratio (c/c) for FR was 69.6% (iMR) and 71.4% (cOR) and for RR 70.9% (iMR) and 71.1% (cOR). For DRG 003, iMR LOS (4.5 d) was shorter than for cOR (14.1 d, P < 0.001) for FR and for RR (8.0 vs. 13.3 d). IMR hospital charges were 43.8% lower than for cOR for FR (P < 0.05) and RR. The iMR costs were lower for FR (46.4%, P < 0.01) and RR (44.7%) than cOR. IMR c/c was 71.4% and 74.8% for cOR. For RR, the iMR c/c was 72.8% and 73.9% for cOR. No RR have followed iMR surgery. COR RR rate was 20% in adults and 30% in children. The mean time from iMR surgery was 11.3 months in adults and 18.0 in children. For the cOR, the mean time to RR was 9.3 months in adults and 13.3 in children. This data suggests that iMR surgery improves net health outcomes by reduced LOS, reduced RR, and reduced hospital charges and costs.

Adolescent↗
PubMed2003

Influence of 1.5-Tesla intraoperative MR imaging on surgical decision making.

To determine the frequency that high-field magnetic resonance (MR) imaging sequences influenced surgical decision making during intraoperative MR-guided surgery. From January 1997 to February 2001, 346 MR-guided procedures were performed using a 1.5-Tesla MR system (NT-ACS, Philips Medical Systems). This system can perform functional MR imaging (fMRI), diffusion weighted imaging (DWI), MR spectroscopy (MRS), MR angiography (MRA), and MR venography (MRV) in addition to T1-weighted, T2-weighted, and turbo FLAIR (fluid-attenuated inversion recovery) imaging. FMRI was used to determine areas of brain activation for language, motor function, and memory. DWI was utilized after tumor resection to exclude cerebral ischemia or infarction. MRS was obtained to identify areas of elevated choline that were suspected to correlate with tumor presence. MRA and MRV localized vascular structures adjacent to tumors prior to resection. The intraoperative procedures performed included 140 brain biopsies of which 82 utilized a trajectory guide and prospective stereotaxy. MRS was used in 42 biopsies (30%), of which 29 had turbo spectroscopic imaging (TSI) and 21 had single voxel spectroscopy (SVS). In all biopsy cases, diagnostic tissue was obtained. There were 103 tumor resections of which 18 (17%) had MRS. Functional MRI was used in 17 cases; 3 biopsies (2%) and 14 planned resections (14%). Speech function was localized in 3 cases, memory function in 3, and motor function in 11. In one case where the motor function of the tongue was intimately involved with a low-grade glioma, resection was not attempted. DWI was used in less than 10% of tumor resections. MRA and MRV were performed in 3 (3%) and 2 (2%) of tumor resections, respectively. The imaging capabilities (i.e., fMRI, DWI, MRA, MRV) associated with high-field intraoperative MR influenced surgical decision making primarily for tumor resections. MRS influenced target selection during brain biopsy.

Biopsy↗
PubMed2003

Measurement and analysis of brain deformation during neurosurgery.

Recent studies have shown that the surface of the brain is deformed by up to 20 mm after the skull is opened during neurosurgery, which could lead to substantial error in commercial image-guided surgery systems. We quantitatively analyze the intraoperative brain deformation of 24 subjects to investigate whether simple rules can describe or predict the deformation. Interventional magnetic resonance images acquired at the start and end of the procedure are registered nonrigidly to obtain deformation values throughout the brain. Deformation patterns are investigated quantitatively with respect to the location and magnitude of deformation, and to the distribution and principal direction of the displacements. We also measure the volume change of the lateral ventricles by manual segmentation. Our study indicates that brain shift occurs predominantly in the hemisphere ipsi-lateral to the craniotomy, and that there is more brain deformation during resection procedures than during biopsy or functional procedures. However, the brain deformation patterns are extremely complex in this group of subjects. This paper quantitatively demonstrates that brain deformation occurs not only at the surface, but also in deeper brain structure, and that the principal direction of displacement does not always correspond with the direction of gravity. Therefore, simple computational algorithms that utilize limited intraoperative information (e.g., brain surface shift) will not always accurately predict brain deformation at the lesion.

Adult↗
PubMed2002

Diffusion-weighted MR imaging findings in carbon monoxide poisoning.

Diffusion-weighted MR imaging (DWI) of two patients with carbon monoxide (CO) poisoning demonstrated white matter and cortical hyperintensities. In one patient, the changes on the FLAIR sequence were more subtle than those on DWI. The DWI abnormality in this patient represented true restriction. In the second patient, repeated exposure to CO caused restricted diffusion. DWI may be helpful for earlier identification of the changes of acute CO poisoning.

Acute Disease↗
PubMed2001

Improving diagnostic yield in brain biopsy: coupling spectroscopic targeting with real-time needle placement.

The purpose of this study was to determine the utility of intraoperative magnetic resonance spectroscopy (MRS) for targeting during brain biopsy using a skull-mounted trajectory guide. From January 1999 to January 2001, 17 patients had intraoperative MRS-guided brain biopsy using a trajectory guide. Ten had turbo spectroscopic imaging (TSI), and seven had both SVS (single-voxel spectroscopy) and TSI. Prospective stereotaxy was used to align the device in a short-bore 1.5-T MR scanner. Areas of elevated choline relative to creatine on SVS and TSI were targeted during the biopsy. Intraoperative imaging confirmed appropriate positioning of the biopsy needle at the time of tissue sampling in all cases. All 17 biopsies (100%) yielded diagnostic tissue. Six patients (34%) had glioblastomas multiforme, three (18%) had anaplastic astrocytomas, three (18%) had anaplastic oligodendrogliomas, two (12%) had radiation necrosis, and one each (6%) had germinoma, ganglioglioma, and astrocytoma. Postoperative imaging confirmed the absence of clinically and radiographically relevant hemorrhage. The findings on SVS correlated with the pathology in all seven cases (100%). In 13 of 17 patients (76%) who had TSI, the spectra correlated well with the permanent pathologic examination. The SVS and TSI spectra were similar in six of seven (86%) cases. Intraoperative MRS-guided brain biopsy using a trajectory guide is a simple, safe, and accurate technique for accessing areas of the brain of diagnostic interest. J. Magn. Reson. Imaging 2001;13:12-15.

Biopsy, Needle↗
PubMed2001

Biopsy needle tip artifact in MR-guided neurosurgery.

A thorough understanding of both the appearance and origin of metallic biopsy needle tip artifact in magnetic resonance imaging (MRI) as well as its interaction with various magnetic resonance (MR) sequence parameters is beneficial for its application in today's MR-guided therapeutic procedures. In a more practical setting, this investigation has focused on the characteristics of MR image artifacts associated with a finite-length metallic needle, specifically at the tip of a biopsy needle when it is approximately parallel to the main magnetic field. The image artifact at needle tip, which exhibits as a blooming ball-shaped signal void, was demonstrated and studied using MR imaging and numerical simulation employing the finite difference method (FDM). In order to understand the origin of this image artifact, a numerical model or simulation software based on the FDM has been developed specifically to solve for the field disturbance to a uniform magnetic field due to a finite-length metallic needle. The solution for magnetic field shows that the field disturbance is spatially localized at the needle tip. From the numerical results, simulated images were generated which were in a very satisfactory agreement MR imaging experiment. Results showed that the MR image artifacts associated with MR-compatible metallic biopsy needles are not only present due to the magnetic susceptibility difference between the needle and its surrounding tissue, but also predictable in routine MR-guided procedures, and the size of the image artifacts could be reduced if optimal imaging parameters were used. J. Magn. Reson. Imaging 2001;13:16-22.

Artifacts↗
PubMed2001

Prospective stereotaxy: a novel method of trajectory alignment using real-time image guidance.

PURPOSE: To describe prospective stereotaxy, a novel method of trajectory alignment that works in real-time. MATERIALS AND METHODS: Prospective stereotaxy was used in minimally-invasive neurosurgical procedures in 74 patients since February 1999. This methodology differs from framed and frameless stereotaxy, both of which are based on retrospective data. Rather, prospective stereotaxy uses real-time MR images to align a surgical trajectory. RESULTS: Phantom tests and clinical procedures in all patients were successfully performed using prospective stereotaxy. In all cases, surgical targets were accessed, and the diagnostic yield of neurobiopsy using prospective stereotaxy was 100%. CONCLUSION: Prospective stereotaxy is applicable to all cross-sectional imaging, and is particularly useful for MR- and CT-guided interventions. The method is simple, reproducible, and accurate in surgical targeting for neurobiopsy and electrode placement. It does not require cumbersome stereotactic frames or expensive optical detectors, and it offers immediate entry into the field of interventional MR with cylindrical MR scanners.

Biopsy, Needle↗
PubMed2001

An efficient chemical shift imaging scheme for magnetic resonance-guided neurosurgery.

An efficient magnetic resonance spectroscopic imaging (MRSI) or chemical shift imaging (CSI) technique based on multiple spin echoes (MSE) has been implemented, validated, and used in both phantom and in vivo MR-guided neurosurgical applications. The key concept of the method is to employ MSE to significantly speed up the data collection rate for mapping hydrogen-containing metabolites. Using an echo train length (ETL) of three per excitation to simultaneously fill three consecutive k-space areas, the total scan time for a spectroscopic image matrix size of 32 x 32 has been shortened to approximately 11 minutes. An interecho spacing time of 273 msec was used to null the phase anomalies of lactate double peaks due to the J-coupling. This allowed a sufficient long data sampling time to achieve 4 Hz spectral resolution. Performing CSI intraopertively during an MR-guided neurosurgical procedure was shown to be feasible at 1.5 T. More importantly, it was shown that more relevant information can be obtained regarding neurochemistry about a targeted lesion, in addition to conventional MR morphological imaging noninvasively. In 25 MR-guided neurosurgical cases, the alleviated choline signal has been found to be consistent with the existence of rapid tumor cell proliferation in the corresponding area. The actual neurobiopsy guided by the spectroscopic imaging method demonstrated that it could provide valuable information in specifying the optimal site in a biopsy procedure, especially in the case involving a nonenhancing tumor. The multiecho scheme has made the CSI technique efficient enough to be routinely used in MR-guided surgical procedures at 1.5 T and also allows the possibility of taking full advantage of MRI capability.

Adult↗
PubMed2001

Subarachnoid hemorrhage associated with cyclosporine A neurotoxicity in a bone-marrow transplant recipient.

We report subarachnoid hemorrhage associated with cyclosporine A (CSA) neurotoxicity after bone-marrow transplantation for chronic myelogenous leukemia. CT showed occipital subarachnoid hemorrhage. MRI confirmed this, and demonstrated cortical and subcortical edema in the posterior temporal, occipital, and posterior frontal lobes bilaterally, which was typical of CSA neurotoxicity. Recognition of CSA neurotoxicity as the cause of the subarachnoid hemorrhage obviated angiographic investigation. After cessation of cyclosporine therapy, the cortical and subcortical edema resolved on follow-up MRI with some residual blood products in the subarachnoid space.

Adult↗
PubMed2001

Intraspinal epidermoid cyst: diffusion-weighted MRI.

We report a 7-year-old boy who presented with two-month history of worsening low back and right leg pain. Conventional MR images demonstrated a poorly outlined intradural mass recognized by the displacement of the conus medullaris and the nerve roots of the cauda equina at the L2-3 level. The signal intensity of the lesion was similar to CSF There was no contrast enhancement of the lesion. Diffusion-weighted images and ADC values revealed restricted diffusion within the mass. Myelography confirmed the mass as an intradural filling defect with myelographic block at the L2-3 level. The patient underwent total surgical excision of the mass. Pathologic examination revealed the diagnosis of epidermoid cyst.

Child↗
PubMed2001

Intra-operative MRI-guided approaches to the pediatric posterior fossa tumors.

INTRODUCTION: The posterior fossa in a child poses a considerable challenge to the neurosurgeon. MRI-guided surgery allows for real time interaction between imaging and the neurosurgeon, not permitted by frameless stereotaxy, and with higher resolution than ultrasound or CT. MATERIALS AND METHODS: The University of Minnesota 1.5 T Phillips interventional MRI was used. From 1997 to 2000, nine posterior fossa intraoperative magnet cases out of eleven were pediatric. The mean age was 6.4 years and the median age 7. Seven midline craniotomies were performed, of which three were re-operations. Two were burr hole placements, one for cyst aspiration and P32 instillation, and the other for tumor biopsy. RESULTS: Two tumors were predominantly in the fourth ventricle, four in the cerebellum, two in the brainstem, and one in the prepontine cystern. Four tumors were juvenile pilocytic astrocytomas, two were anaplastic astrocytomas, and one each was ependymoma, craniopharyngioma cyst, and medulloblastoma. Four patients had complete radiologic resection. Two had maximal resections limited by vital structures. P32 instillation and tumor biopsy were done in a single pass. Follow-up ranged from 3 months to 1.4 years. The cyst that was aspirated and had P32 instillation remains absent. The two mortalities were in the patients with medulloblastoma and anaplastic astrocytoma. There were no intra-operative mortalities. The other patient with anaplastic astrocytoma progressed. The remainder had stable imaging. CONCLUSION: MRI-guided surgery results in improved resection imaging and real-time needle guidance in tumor operations. Its value could lie in low-grade lesions, where maximal resection is most beneficial.

Child↗