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Alim P. Mitha, Erin E. Murphy and Christopher S. Ogilvy

✓ In this report, the authors present the case of a patient with a unique type of spinal arteriovenous fistula. Both the location and venous angioarchitecture of this variant are uncommon, making diagnosis of the lesion challenging and raising particular management issues. The authors discuss this unusual lesion and describe its imaging features and surgical findings, as well as highlight its pathological abnormalities.

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John H. Wong, Alim P. Mitha, Morgan Willson, Mark E. Hudon, Robert J. Sevick and Richard Frayne

Object

Digital subtraction (DS) angiography is the current gold standard of assessing intracranial aneurysms after coil placement. Magnetic resonance (MR) angiography offers a noninvasive, low-risk alternative, but its accuracy in delineating coil-treated aneurysms remains uncertain. The objective of this study, therefore, is to compare a high-resolution MR angiography protocol relative to DS angiography for the evaluation of coil-treated aneurysms.

Methods

In 2003, the authors initiated a prospective protocol of following up patients with coil-treated brain aneurysms using both 1.5-tesla gadolinium-enhanced MR angiography and biplanar DS angiography. Using acquired images, the subject aneurysm was independently scored for degree of remnant identified (complete obliteration, residual neck, or residual aneurysm) and the surgeon's ability to visualize the parent vessel (excellent, fair, or poor).

Results

Thirty-seven patients with 42 coil-treated aneurysms were enrolled for a total of 44 paired MR angiography–DS angiography tests (median 9 days between tests). An excellent correlation was found between DS and MR angiography for assessing any residual aneurysm, but not for visualizing the parent vessel (κ = 0.86 for residual aneurysm and 0.10 for parent vessel visualization). Paramagnetic artifact from the coil mass was minimal, and in some cases MR angiography identified contrast permeation into the coil mass not revealed by DS angiography. An intravascular microstent typically impeded proper visualization of the parent vessel on MR angiography.

Conclusions

Magnetic resonance angiography is a noninvasive and safe means of follow-up review for patients with coil-treated brain aneurysms. Compared with DS angiography, MR angiography accurately delineates residual aneurysm necks and parent vessel patency (in the absence of a stent), and offers superior visualization of contrast filling within the coil mass. Use of MR angiography may obviate the need for routine diagnostic DS angiography in select patients.

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Alim P. Mitha, John H. Wong, Jian-Qiang Lu, William F. Morrish, Mark E. Hudon and William Y. Hu

✓ To the authors' knowledge, only 1 case of communicating hydrocephalus after endovascular coiling of unruptured brain aneurysms has been reported previously. Here, they report on 2 such cases of delayed communicating hydrocephalus after treatment with hydrogel-coated coils and offer the first histopathological evidence of foreign material, presumably related to the coils, as the cause of hydrocephalus.

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Patrick J. Codd, Alim P. Mitha and Christopher S. Ogilvy

Arteriovenous malformations are generally considered to be cured following angiographically proven complete resection. However, rare instances of AVM recurrence despite negative findings on postoperative angiography have been reported in both children and adults. In this paper, the authors present the case of a 33-year-old woman with 2 AVM recurrences. This patient represents the oldest case of recurrent AVM, and the first adult double recurrence reported in the literature. The case is presented, the radiological and surgical features are considered, and the literature on recurrent AVMs is reviewed.

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Kelly J. Bullivant, Alim P. Mitha and Mark G. Hamilton

The PS Medical Strata valve is a programmable shunt valve used in the treatment of hydrocephalus that allows for noninvasive changes in the pressure setting using a magnet. The Strata valve is sensitive to magnetic fields, and reprogramming is frequently necessary after MR imaging. A known but rare complication of the Strata valve is that the rotor can become locked, causing shunt malfunction. This complication can only occur in a first generation Strata valve.

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Alim P. Mitha, Kelly J. Bullivant, Julie L. Lauzon and Walter J. Hader

Macrocephaly-cutis marmorata telangiectatica congenita is a rare overgrowth syndrome commonly associated with hydrocephalus. Although the pathophysiological characteristics of the hydrocephalus in this syndrome is not fully known, previous reports have described its treatment with ventriculoperitoneal shunt placement. The authors describe 2 cases of macrocephaly-cutis marmorata telangiectatica congenita successfully treated for progressive hydrocephalus with endoscopic third ventriculostomy. Both patients experienced clinical and radiographic stabilization following treatment, and these findings offer insight into the pathophysiology of the hydrocephalus and its ideal management.

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Alim P. Mitha, Benjamin Reichardt, Michael Grasruck, Eric Macklin, Soenke Bartling, Christianne Leidecker, Bernhard Schmidt, Thomas Flohr, Thomas J. Brady, Christopher S. Ogilvy and Rajiv Gupta

Object

Imaging of intracranial aneurysms using conventional multidetector CT (MDCT) is limited because of nonvisualization of features such as perforating vessels, pulsatile blebs, and neck remnants after clip placement or coil embolization. In this study, a model of intracranial saccular aneurysms in rabbits was used to assess the ultra-high resolution and dynamic scanning capabilities of a prototype flat-panel volumetric CT (fpVCT) scanner in demonstrating these features.

Methods

Ten New Zealand white rabbits underwent imaging before and after clipping or coil embolization of surgically created aneurysms in the proximal right carotid artery. Imaging was performed using a prototype fpVCT scanner, a 64-slice MDCT scanner, and traditional catheter angiography. In addition to the slice data and 3D views, 4D dynamic views, a capability unique to fpVCT, were also created and reviewed. The images were subjectively compared on 1) 4 image quality metrics (spatial resolution, noise, motion artifacts, and aneurysm surface features); 2) 4 posttreatment features reflecting the metal artifact profile of the various imaging modalities (visualization of clip or coil placement, perianeurysmal clip/coil anatomy, neck remnant, and white-collar sign); and 3) 2 dynamic features (blood flow pattern and aneurysm pulsation).

Results

Flat-panel volumetric CT provided better image resolution than MDCT and was comparable to traditional catheter angiography. The surface features of aneurysms were demonstrated with much higher resolution, detail, and clarity by fpVCT compared with MDCT and angiography. Flat-panel volumetric CT was inferior to both MDCT and angiography in terms of image noise and motion artifacts. In fpVCT images, the metallic artifacts from clips and coils were significantly fewer than those in MDCT images. As a result, clinically important information about posttreatment aneurysm neck remnants could be derived from fpVCT images but not from MDCT images. Time-resolved dynamic sequences were judged slightly inferior to conventional angiography but superior to static MDCT images.

Conclusions

The spatial resolution, surface anatomy visualization, metal artifact profile, and 4D dynamic images from fpVCT are superior to those from MDCT. Flat-panel volumetric CT demonstrates aneurysm surface features to better advantage than angiography and is comparable to angiography in metal artifact profile. Even though the temporal resolution of fpVCT is not quite as good as that of angiography, fpVCT images yield clinically important anatomical information about aneurysm surface features and posttreatment neck remnants not attainable with either angiography or MDCT images.

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Adib A. Abla, Jay D. Turner, Alim P. Mitha, Gregory Lekovic and Robert F. Spetzler

Brainstem cavernous malformations (CMs) are low-flow vascular lesions in eloquent locations. Their presentation is often marked with symptomatic hemorrhages that appear to occur more frequently than hemorrhage from supratentorial cavernomas. Brainstem CMs can be removed using 1 of the 5 standard skull-base approaches: retrosigmoid, suboccipital (with or without telovelar approach), supracerebellar infratentorial, orbitozygomatic, and far lateral.

Patients being referred to a tertiary institution often have lesions that are aggressive with respect to bleeding rates. Nonetheless, the indications for surgery, in the authors' opinion, are the same for all lesions: those that are symptomatic, those that cause mass effect, or those that abut a pial surface. Patients often have relapsing and remitting courses of symptoms, with each hemorrhage causing a progressive and stepwise decline. Many patients experience new postoperative deficits, most of which are transient and resolve fully. Despite the risks associated with operating in this highly eloquent tissue, most patients have had favorable outcomes in the authors' experience. Surgical treatment of brainstem CMs protects patients from the potentially devastating effects of rehemorrhage, and the authors believe that the benefits of intervention outweigh the risks in patients with the appropriate indications.

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Alim P. Mitha, Jay D. Turner, Adib A. Abla, A. Giancarlo Vishteh and Robert F. Spetzler

Object

The management of intramedullary spinal cord cavernous malformations (CMs) is controversial. At Barrow Neurological Institute, the authors selectively offer surgical treatment for symptomatic spinal cord CMs. The purpose of this paper is to review the clinical outcomes in patients after resection of these lesions based on a single-center experience over a 25-year period.

Methods

The records of 80 patients who underwent resection of pathologically confirmed spinal cord CMs from January 1985 to May 2010 were analyzed retrospectively. Preoperative clinical status and imaging findings were evaluated as well as immediate and long-term postoperative outcomes.

Results

Compared with their preoperative Frankel grade, 11% of patients were worse, 83% were the same, and 6% improved immediately after surgery. At a mean follow-up interval of 5 years, 10% of patients were worse, 68% were the same, and 23% were improved compared with their preoperative status. Five percent of patients underwent reoperation for resection of a symptomatic residual or recurrent lesion. Immediate complications were encountered in 6% of patients, including CSF leakage and deep venous thrombosis. Long-term complications were encountered in 14% of patients and included kyphotic deformity, stenosis, and spinal cord tethering. A significant correlation was found between long-term outcome and anteroposterior length of the lesion (p = 0.01).

Conclusions

The resection of intramedullary spinal cord CMs can be achieved with good long-term outcomes and an acceptable risk of immediate or delayed complications.

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Joshua P. Aronson, Alim P. Mitha, Brian L. Hoh, Pavan K. Auluck, Irina Pomerantseva, Joseph P. Vacanti and Christopher S. Ogilvy

Object

Recurrence after endovascular coiling of intracranial aneurysms is reported in up to 42% of cases and is attributed to the lack of endothelialization across the neck. In this study the authors used a novel tissue engineering approach to promote endothelialization by seeding endothelial progenitor cells (EPCs) within a fibrin polymer injected endovascularly into the aneurysm.

Methods

Experimental aneurysms were created in New Zealand White rabbits and were left untreated, surgically clipped, or embolized with platinum coils, fibrin biopolymer alone, or fibrin combined with autologous cultured EPCs.

Results

In aneurysms treated with EPCs, a confluent monolayer of endothelial cells with underlying neointima was demonstrated across the neck at 16 weeks posttreatment, which was not observed with aneurysms treated using the other methods.

Conclusions

This novel technique may address reasons for the limited durability of standard coil embolization and provides further avenues for the development of improved devices for the care of patients with aneurysms.