Steven G. Imbesi

Metabolite findings in tumefactive demyelinating lesions utilizing short echo time proton magnetic resonance spectroscopy.

Utilizing Short Echo Time Proton Magnetic Resonance Spectroscopy The February 2007 issue of the American Journal of Neuroradiology reported the findings of A. Ciafoni et al. In this article, the authors reported the approach of examining glutamate/glutamine peaks in H-MR (proton) spectroscopy to increase the specificity in differentiating tumefactive demyelinating processes from neoplasms. The thought of using MR spectroscopy in this situation is attractive because the current clinical approach may warrant a lumbar puncture and even biopsy. Although we commend the authors’ enthusiasm for this technique, the paper lacks statistical significance and contains much bias to support the authors’ claim that MR spectroscopy “can be helpful in the noninvasive diagnosis of acute demyelinating diseases” when elevated glutamate/glutamine peaks are identified. We believe that this article should be represented as an idea backed by case reports and not be considered as original research. First, the authors never fully give the inclusion or exclusion criteria for how the 4 patients in the study were chosen. Were any patients excluded from the study, and, if so, why? They state that the spectroscopy was performed on 4 patients with neurologic symptoms and a diagnosis of parenchymal mass lesions on MR imaging. It seems unlikely that the first 4 patients who entered the study had the diagnosis of tumefactive multiple sclerosis. There must have been some patients originally selected who ended up with the diagnosis of a neoplasm. Why were these spectroscopy results not included in the study? They fail to notify the reader if the diagnosis was already known at the time of selection and if the interpreter of the spectral data was blinded. Obviously, these effects can cause bias, which would alter the outcome of the study. The potential for bias is evident if one examines the 2.1 to 2.5 region of the spectra where complex, unresolved resonances produce a “shoulder” of variable slope downfield from the N-acetylaspartate resonance. The fluctuations in the spectral intensity in this region are similar to the background noise (eg, Fig 2), which makes the assignment of a single peak height for the entire range challenging. Unfortunately, the authors have not described in detail their method for determining , -Glx peak heights, and they have not documented the accuracy of the method for detecting changes in glutamine/glutamate levels (eg, in phantoms). Second, no control is used. Referencing the article by Majos et al is not a substitute for using a control group with known neoplasms. Showing that a neoplasm does not increase the glutamate/glutamine peak would have added significantly to this article. Also, other demyelinating diseases are not included. Finally, no statistical inference can be made in a study with only 4 patients; the study lacks statistical power. For these reasons, we believe that this study should not be represented as original research, but as a novel idea with associated case reports to back up the need for more comprehensive research in this area. The facts in this study are not significant enough to suggest that MR spectroscopy “can be helpful” in distinguishing between tumefactive demyelinating diseases and neoplasm.

Rapid prototyping to create vascular replicas from CT scan data: making tools to teach, rehearse, and choose treatment strategies.

Our goal was to develop and prove the accuracy of a system that would allow us to re‐create live patient arterial pathology. Anatomically accurate replicas of blood vessels could allow physicians to teach and practice dangerous interventional techniques and might also be used to gather basic physiologic information. The preparation of replicas has, until now, depended on acquisition of fresh cadaver material. Using rapid prototyping, it should be able to replicate vascular pathology in a live patient. We obtained CT angiographic scan data from two patients with known arterial abnormalities. We took such data and, using proprietary software, created a 3D replica using a commercially available rapid prototyping machine. From the prototypes, using a lost wax technique, we created vessel replicas, placed those replicas in the CT scanner, then compared those images with the original scans. Comparison of the images made directly from the patient and from the replica showed that with each step, the relationships were maintained, remaining within 3% of the original, but some smoothing occurred in the final computer manipulation. From routinely obtainable CT angiographic data, it is possible to create accurate replicas of human vascular pathology with the aid of commercially available stereolithography equipment. Visual analysis of the images appeared to be as important as the measurements. With 64 and 128 slice detector scanners becoming available, acquisition times fall enough that we should be able to model rapidly moving structures such as the aortic root.

Intramedullary spinal cord metastasis of lung adenocarcinoma presenting as Brown-Sequard syndrome.

BACKGROUND It is extremely rare for cancer to present first as an intramedullary spinal cord metastasis. Furthermore, because it is unlikely for spinal cord neoplasm to present acutely, an acute presentation may signify metastatic disease and should be considered in the initial differential diagnosis. METHODS The authors present a case of a 59-year-old man presenting with Brown-Sequard syndrome and in whom metastatic lung adenocarcinoma to the spinal cord was subsequently discovered. Review of the literature reveals this case to be one of only a very few where intramedullary tumor was the first manifestation of metastatic disease. RESULTS The mainstay of treatment for intramedullary spinal metastases remains steroids, radiation, and chemotherapy, though no well-designed study compares these modalities by long-term survival and functional results. This patient underwent local radiation and systemic chemotherapy following surgical resection. CONCLUSIONS This patient had no preoperative signs suggesting disease in other organs, making the diagnosis of lung adenocarcinoma metastatic to the intramedullary cord surprising, especially given the extremely rare incidence of spinal intramedullary metastatic disease. However, the patient had an acute presentation, uncommon for primary neoplasm, which may be an indication of metastatic disease.

Role of proton magnetic resonance spectroscopy in the diagnosis of gliomatosis cerebri: a unique pattern of normal choline but elevated Myo-inositol metabolite levels.

A patient with histologically proven gliomatosis cerebri presented with a normal choline level but a markedly abnormal elevated myo-inositol level on magnetic resonance (MR) spectroscopy. We describe the case presentation, imaging findings (in particular, the unique MR spectroscopic pattern), and their significance regarding the diagnosis of this relatively rare neoplasm.

Intramedullary spinal cord astrolipoma: case report.

OBJECTIVE AND IMPORTANCEReported is a case of a thoracic intramedullary astrocytoma with a lipomatous component, a so-called astrolipoma. This is the only known case of a single intraspinal astrolipoma in an otherwise healthy patient. CLINICAL PRESENTATIONThe patient was a 36-year-old woman with dorsal thoracic pain of more than 1 month’s duration, mild lower extremity weakness, and incomplete sensory loss to the T10 level. INTERVENTIONMagnetic resonance imaging of the thoracolumbar spine revealed a fusiform mass at the T9–T11 level. The patient underwent T9–T11 laminectomies and complete resection of the tumor. In the initial postoperative period, the patient’s symptoms worsened. However, 3 months after surgery, the patient was clinically improved and was able to walk without assistance. Twelve months after surgery, imaging revealed no evidence of tumor. CONCLUSIONThe current treatment plan and recommendation, assuming this tumor will behave like a low-grade glioma or lipoma, is continued radiographic surveillance after gross total resection. Reresection is recommended for tumor recurrence or significant regrowth. The long-term prognosis for astrolipoma is unknown.

Development of a posterior cerebral artery aneurysm subsequent to occlusion of the contralateral internal carotid artery for giant cavernous aneurysm

We report a case of a patient who developed a left posterior cerebral artery aneurysm 5 years after balloon occlusion of the right internal carotid artery for a giant cavernous aneurysm. The location of the new aneurysm was outside of the primary collateral pathways to the contralateral, proximally occluded, anterior circulation, illustrating the complexity of hemodynamic factors contributing to the development of intracranial saccular aneurysms. The appearance of an aneurysm in this setting supports the hypothesis that degenerative factors and hemodynamic stresses are important in the etiology of intracranial aneurysms.

Rheumatoid leptomeningitis: magnetic resonance imaging and pathologic findings--a case report.

Rheumatoid arthritis (RA) is a chronic inflammatory multisystem disease with articular and extra‐articular manifestations. Intracranial manifestations of RA are rare. Purpose of this article is to report on a rarely described leptomeningeal involvement in RA, and on its neuroimaging features, including diffusion‐weighted imaging (DWI).

Diffusion-weighted imaging distinguishes recurrent epidermoid neoplasm from postoperative arachnoid cyst in the lumbosacral spine

Diffusion-weighted imaging can be used to distinguish epidermoid tumor from arachnoid cyst in the intracranial compartment. We report the use of diffusion-weighted imaging in a postoperative spine to successfully distinguish a recurrent epidermoid tumor from arachnoid cyst in a noninvasive manner. Our case illustrates the value of this readily available sequence presently not generally used in the clinical evaluation of spinal pathology.

Treatment of ischemic stroke complicating cardiac catheterization with systemic thrombolytic therapy

Ischemic stroke is a rare but serious complication of cardiac catheterization. We report a case in which systemic thrombolytic therapy was successfully utilized in treating a patient with a cerebellar stroke, leading to obtundation during elective cardiac catheterization. Underlying bilateral vertebrobasilar disease with thrombotic embolization to the basilar artery was postulated to be the pathophysiological basis for the stroke and subsequent success of thrombolytic treatment in this patient. As the consequences of this rare complication are severe, systemic thrombolytic therapy should be considered for patients suffering an acute ischemic stroke during cardiac catheterization or percutaneous coronary intervention.

Multifocal intravascular papillary endothelial hyperplasia in the retroperitoneum and spine: A case report and review of the literature

The authors present a unique case of intravascular papillary endothelial hyperplasia (IPEH) localized in the renal hilum, retroperitoneum, and spine in a patient with Wegener granulomatosis. IPEH rarely occurs in the abdomen or spine with few cases reported in the literature. No case has been reported of IPEH involving both the retroperitoneum and spine. In our case, MR imaging revealed enhancing masses in the right renal hilum and retroperitoneum as well as multiple focal enhancing lesions throughout the spine with lower thoracic ventral thecal sac compression. The diagnosis was established by resection of the renal hilum mass, and interval follow‐up is deemed necessary for the remaining lesions because the long‐term evolution of IPEH with conservative treatment alone is not well established. J. Magn. Reson. Imaging 2009;29:957–961.