MR Imaging Features of Critical Spinal Demyelinating Lesions Associated with Progressive Motor Impairment.

BACKGROUND AND PURPOSE: Progressive MS is typically heralded by a myelopathic pattern of asymmetric progressive motor weakness. Focal individual "critical" demyelinating spinal cord lesions anatomically associated with progressive motor impairment may be a compelling explanation for this clinical presentation as described in progressive solitary sclerosis (single CNS demyelinating lesion), progressive demyelination with highly restricted MR imaging lesion burden (2-5 total CNS demyelinating lesions; progressive paucisclerotic MS), and progressive, exclusively unilateral hemi- or monoparetic MS (>5 CNS demyelinating progressive unilateral hemi- or monoparetic MS [PUHMS] lesions). Critical demyelinating lesions appear strikingly similar across these cohorts, and we describe their specific spinal cord MR imaging characteristics. MATERIALS AND METHODS: We performed a retrospective, observational MR imaging study comparing spinal cord critical demyelinating lesions anatomically associated with progressive motor impairment with any additional "noncritical" (not anatomically associated with progressive motor impairment) spinal cord demyelinating lesions. All spinal cord MR images (302 cervical and 91 thoracic) were reviewed by an experienced neuroradiologist with final radiologic assessment on the most recent MR imaging. Anatomic association with clinical progressive motor impairment was confirmed independently by MS subspecialists. RESULTS: Ninety-one individuals (PUHMS, 37 [41%], progressive paucisclerosis 35 [38%], progressive solitary sclerosis 19 [21%]) with 91 critical and 98 noncritical spinal cord MR imaging demyelinating lesions were evaluated. MR imaging characteristics that favored critical spinal cord demyelinating lesions over noncritical lesions included moderate-to-severe, focal, lesion-associated spinal cord atrophy: 41/91 (45%) versus 0/98 (0%) (OR, 161.91; 9.43 to >999.9); lateral column axial location (OR, 10.43; 3.88-28.07); central region (OR, 3.23; 1.78-5.88); ventral column (OR, 2.98; 1.55-5.72); and larger lesion size of the axial width (OR, 2.01;1.49-2.72), transverse axial size (OR, 1.66; 1.36-2.01), or lesion area (OR, 1.14; 1.08-1.2). Multiple regression analysis revealed focal atrophy and lateral axial location as having the strongest association with critical demyelinating lesions. CONCLUSIONS: Focal, lesion-associated atrophy, lateral column axial location, and larger lesion size are spinal cord MR imaging characteristics of critical demyelinating lesions. The presence of critical demyelinating lesions should be sought as these features may be associated with the development of progressive motor impairment in MS.

Analysis of Brain SPECT Images Coregistered with MRI in Patients with Epilepsy: Comparison of Three Methods.

BACKGROUND AND PURPOSE: SISCOM and STATISCOM were clinically proved to be effective for ictal/inter-ictal single-photon emission computed tomography (SPECT) analysis coregistered with magnetic resonance imaging (MRI) for seizure localization. Recently, a software package also became available for this analysis. This study aimed to investigate and compare the performance of these analysis methods for seizure localization. METHODS: A total of 378 patients who underwent 99m Tc-ethyl cysteinate dimer (ECD) SPECT scans were retrospectively reviewed and 28 remained after applying exclusion criteria. Their SPECT and MRI images were analyzed with SISCOM (with z-score of 1.5 and 2), STATISCOM, and MIMneuro, resulting in a total of 112 image data sets. Two experienced radiologists participated in the blind review process using a custom tool and they can mark up to two hyper- and/or hypoperfusion regions. Their review results were analyzed using the Jackknife Free Response Receiver-Operating Characteristics (JAFROC) test and the JAFROC figure-of-merit (FoM) was reported for each method. The interobserver agreement was also assessed using Cohen's kappa test. RESULTS: Based on the readers' two choices, averaged FoM was 85.7%, 83.9%, 66.1%, and 51.8% for STATISCOM, MIMneuro, SISCOM (z-score = 2), and SISCOM (z-score = 1.5), respectively. The average confidence rating was 2.5, 2.3, 1.6, and 1.1 for STATISCOM, MIMneuro, SISCOM (z-score = 2), and SISCOM (z-score = 1.5), respectively. For interobserver agreement, kappa was .742 for STATISCOM, .816 for MIMneuro, .517 for SISCOM (z-score = 2), and .441 for SISCOM (z-score = 1.5; all P < .001). CONCLUSION: Our study demonstrated that STATISCOM showed the best performance for seizure localization, which was closely followed by MIMneuro. In addition, MIMneuro was not inferior to SISCOM with either z-score.

Progressive Brain Atrophy in Super-refractory Status Epilepticus.

IMPORTANCE: Prolonged seizures in super-refractory status epilepticus (SRSE) have been shown to cause neuronal death and reorganization, and visual inspection in individual case studies has demonstrated progressive cortical and subcortical atrophy. At present, magnetic resonance imaging (MRI) studies that evaluate brain atrophy in SRSE are lacking. OBJECTIVES: To document and quantify the development of atrophy over time in SRSE. DESIGN, SETTING, AND PARTICIPANTS: This retrospective medical record review included all patients with SRSE who were admitted to a tertiary referral campus of the Mayo Clinic Hospital with SRSE from January 1, 2001, to December 31, 2013. Patients with (1) an initial MRI scan performed within 2 weeks of SRSE onset, (2) a second MRI scan within 6 months of SRSE resolution, and (3) a minimum duration of 1 week between MRI scans were included. The ventricular brain ratio (VBR) was measured on T2-weighted fluid-attenuated inversion recovery (FLAIR) images at disease onset and during follow-up. Measurements were performed on axial FLAIR images with section thickness of less than 5 mm. The plane immediately superior to the caudate head was chosen for analysis. The hypothesis that atrophy develops during SRSE despite seizure control (electroencephalogram background suppression with anesthetic drugs) was tested. Data were analyzed from June 1 to December 31, 2015. MAIN OUTCOMES AND MEASURES: Change in VBR (ΔVBR) as a percentage of the starting measure. RESULTS: Nineteen patients met the inclusion criteria; these included 10 men (53%) and 9 women (47%) with a median age of 41 (interquartile range [IQR], 25-68) years. Anesthetic agents were required for a median of 13 (IQR, 5-37) days. Initial MRI was performed a median of 2 (IQR, 1-7.5) days from the onset of SRSE, and the second MRI was performed a median of 11 (IQR, 5-15.5) days from the resolution of SRSE, with a median of 40 (IQR, 15-65) days between MRI scans. Median ΔVBR was 23.3% (IQR, 10.5%-70.3%). A significant correlation between the duration of anesthetic agent use and ΔVBR was found (Spearman r = 0.54; P = .02). CONCLUSIONS AND RELEVANCE: Atrophy developed in all patients with SRSE who underwent serial imaging, despite administration of agents for seizure control. The degree of atrophy appears to be related to the duration of SRSE.

Double Inversion Recovery Magnetic Resonance Imaging in Identifying Focal Cortical Dysplasia.

BACKGROUND: Focal cortical dysplasia is commonly recognized in pediatric epilepsy surgery. Despite characteristic radiographic features, focal cortical dysplasia can be subtle on magnetic resonance imaging. Double inversion recovery acquisition suppresses the white matter signal, which may enhance visualization of abnormal features at the gray-white matter interface. We assessed the ability of double inversion recovery to distinguish focal cortical dysplasia from periventricular nodular heterotopia and normal brain. METHODS: Patients with focal cortical dysplasia were identified from our patient database, as was a control group comprising patients with periventricular nodular heterotopia and healthy persons. A senior neuroradiologist reviewed all clinical images and classified them as patients with focal cortical dysplasia (n = 16) or control subjects (periventricular nodular heterotopia, n = 13; normal, n = 20). Four neuroradiologists reviewed the de-identified and randomized double inversion recovery and magnetization prepared rapid acquired gradient echoes (MPRAGE) sequences for each person and scored them as normal, focal cortical dysplasia, or periventricular nodular heterotopia. RESULTS: Among individual reviewers, double inversion recovery showed sensitivity from 50% to 88% and specificity from 67% to 91% in detecting focal cortical dysplasia. The sensitivity was notably higher in reviewers with more clinical experience with the technique. Consensus agreement among the three most experienced reviewers gave a sensitivity of 88% (95% confidence interval [CI], 72% to 97%) and specificity of 88% (95% CI, 62% to 98%) for double inversion recovery and sensitivity of 44% (95% CI, 20% to 70%) and specificity of 100% (95% CI, 89% to 100%) for MPRAGE. CONCLUSIONS: Double inversion recovery is sensitive for detection of focal cortical dysplasia with experienced users, particularly when there is consensus agreement. The use of two clinically available magnetic resonance imaging acquisitions-double inversion recovery and another sequence with high specificity such as MPRAGE-would be complementary in the evaluation of lesional epilepsy.

Rezum System Water Vapor Treatment for Lower Urinary Tract Symptoms/Benign Prostatic Hyperplasia: Validation of Convective Thermal Energy Transfer and Characterization With Magnetic Resonance Imaging and 3-Dimensional Renderings.

OBJECTIVE: To evaluate by magnetic resonance imaging the physical effects of convective thermal energy transfer with water vapor as a means of treating lower urinary tract symptoms due to benign prostatic hyperplasia. METHODS: Sixty-five men with lower urinary tract symptoms were treated with the Rezum System by transurethral intraprostatic injection of water vapor. A group of 45 of these men consented to undergo a series of gadolinium-enhanced magnetic resonance imagings of the prostate after treatment to monitor the size and location of ablative lesions, their time course of resolution, and the corresponding change in prostate tissue volume. Visualization was conducted at 1 week, 1, 3, and 6 months after treatment. RESULTS: Outcomes were available for 44 patients. Convective thermal lesions were limited to the transition zone and correlated with targeted treatment locations. At 1 week after treatment, the mean volume of ablative lesions was 8.2 cm(3) (0.5-24.0 cm(3)). At 6 months, whole prostate volume was reduced by a mean of 28.9% and transition zone volume by 38.0% as compared with baseline 1-week images. At 3 and 6 months after treatment, the lesion volumes had reduced by 91.5% and 95.1%, respectively. Lesions remained within the targeted treatment zone without compromising integrity of the bladder, rectum, or striated urinary sphincter. CONCLUSION: This imaging study confirms the delivery of convective water vapor technology to create thermal lesions in the prostate tissue. Lesions generated underwent near complete resolution by 3 and 6 months after treatment with a concomitant one-third reduction in overall prostate and transition zone volumes.

Statistical SPECT processing in MRI-negative epilepsy surgery.

OBJECTIVE: To evaluate the benefit of statistical SPECT processing over traditional subtraction methods, we compared ictal-interictal SPECT analyzed by statistical parametric mapping (SPM) (ISAS), statistical ictal SPECT coregistered to MRI (STATISCOM), and subtraction ictal-interictal SPECT coregistered with MRI (SISCOM) in patients with MRI-negative focal temporal lobe epilepsy (nTLE) and extratemporal lobe epilepsy (nETLE). METHODS: We retrospectively identified 49 consecutive cases of drug-resistant focal epilepsy that had a negative preoperative MRI and underwent interictal and ictal SPECT prior to resective epilepsy surgery. Interictal and ictal SPECT scans were analyzed using SISCOM, ISAS, and STATISCOM to create hyperperfusion and hypoperfusion maps for each patient. Reviewers blinded to clinical data and the SPECT analysis method marked the site of probable seizure origin and indicated their confidence in the localization. RESULTS: In nTLE and nETLE, the hyperperfusions detected by STATISCOM (71% nTLE, 57% nETLE) and ISAS (67% nTLE, 53% nETLE) were more often colocalized with surgery resection site compared to SISCOM (38% nTLE, 36% nETLE). In nTLE, localization of the hyperperfusion to the region of surgery was associated with an excellent outcome for STATISCOM (p = 0.005) and ISAS (p = 0.027), but not in SISCOM (p = 0.071). This association was not present in nETLE for any method. CONCLUSION: In an unselected group of patients with normal MRI and focal epilepsy, SPM-based methods of SPECT processing showed better localization of SPECT hyperperfusion to surgical resection site and higher interobserver agreement compared to SISCOM. These results show the benefit of statistical SPECT processing methods and further highlight the challenge of nETLE.

Mapping high-fidelity volume rendering for medical imaging to CPU, GPU and many-core architectures.

Medical volumetric imaging requires high fidelity, high performance rendering algorithms. We motivate and analyze new volumetric rendering algorithms that are suited to modern parallel processing architectures. First, we describe the three major categories of volume rendering algorithms and confirm through an imaging scientist-guided evaluation that ray-casting is the most acceptable. We describe a thread- and data-parallel implementation of ray-casting that makes it amenable to key architectural trends of three modern commodity parallel architectures: multi-core, GPU, and an upcoming many-core Intel architecture code-named Larrabee. We achieve more than an order of magnitude performance improvement on a number of large 3D medical datasets. We further describe a data compression scheme that significantly reduces data-transfer overhead. This allows our approach to scale well to large numbers of Larrabee cores.

Characterizing TUNA ablative treatments of the prostate for benign hyperplasia with gadolinium-enhanced magnetic resonance imaging.

BACKGROUND AND PURPOSE: Transurethral Needle Ablation of the prostate TUNA has been accepted as an office-based treatment for benign prostatic hyperplasia (BPH) for many years. Clinical outcomes have been reported, but the amount and location of the necrosis produced have yet to be characterized. The necrosis caused by TUNA was evaluated by gadolinium-enhanced magnetic resonance imaging (MRI) of the pelvis. PATIENTS AND METHODS: Twelve patients with BPH/lower urinary-tract symptoms underwent standard TUNA, and MRI scans with gadolinium enhancement were performed before and 1 week after treatment. The images were studied using Analyze software to quantify the amount of necrosis compared with the prostatic volume. Transverse, coronal, and sagittal images were obtained to identify the location of the necrosis. RESULTS: New gadolinium defects were seen in all patients after TUNA. The lesions coalesced into continuous areas of necrosis and correlated with the site of needle placement. The mean volume of necrosis was 6.84 cc and equated to 8.6% of the prostate volume. No lesions were found near the apex, urethra, or rectum; and none extended beyond the prostate capsule. CONCLUSIONS: Gadolinium-enhanced MRI demonstrates new vascular defects representing necrosis caused by TUNA of the prostate. This therapy for BPH produces necrotic lesions that can be placed strategically by the surgeon. The standard protocol produces lesions that coalesce to create larger lesions. This MRI study has characterized, for the first time, the heating pattern and intraprostatic necrosis of a complete TUNA procedure.

Sp1 family of transcription factors regulates the human alpha2 (XI) collagen gene (COL11A2) in Saos-2 osteoblastic cells.

UNLABELLED: Genes encoding type XI collagen, normally associated with chondrogenesis, are also expressed by osteoblasts. By studying Saos-2 cells, we showed that the transcription factors, Sp1, Sp3, and Sp7 (Osterix), regulate COL11A2 expression through its proximal promoter. The findings indicate both ubiquitous and osteoblast-specific mechanisms of collagen gene regulation. INTRODUCTION: Type XI collagen is essential for skeletal morphogenesis. Collagen XI gene regulation has been studied in chondrocytes but not in osteoblasts. MATERIALS AND METHODS: We cultured Saos-2 cells, a human osteosarcoma-derived line of osteoblasts, and analyzed them for alpha2(XI) protein and COL11A2 regulatory mechanisms. RESULTS AND CONCLUSIONS: Although types I and V were the dominant collagens deposited by Saos-2 cells, they expressed COL11A2 mRNA, and alpha2(XI) chains were present in the extracellular matrix. The COL11A2 promoter region (from -149 to -40) containing three Sp1 binding sites was required for promoter activity in transient transfection assays. All three Sp1 sites were critical for binding by nuclear proteins in electrophoretic mobility shift assays. Further analysis using consensus oligonucleotides and specific antibodies as well as chromatin immunoprecipitation assay implicated Sp1 and Sp3 in binding to this promoter region. Overexpressing Sp1 or Sp3 significantly increased COL11A2 promoter activity and endogenous COL11A2 gene expression, an effect that was suppressed by the Sp1-binding inhibitor mithramycin A. Further experiments showed that Sp1, Sp3, CREB-binding protein (CBP), p300, and histone deacetylase (HDAC) were physically associated and HDAC inhibitors (trichostatin A or NaB) upregulated COL11A2 promoter activity and endogenous gene expression. Another Sp1 family member, Sp7 (Osterix), was expressed in Saos-2 cells, but not in chondrocytes, and was shown by chromatin immunoprecipitation to occupy the COL11A2 promoter. Overexpressing Sp7 increased COL11A2 promoter activity and endogenous gene expression, an effect also blocked by mithramycin A. Using siRNA to knockdown Sp1, Sp3, or Sp7, it was shown that depression of any of them decreased COL11A2 promoter activity and endogenous gene expression. Finally, primary cultures of osteoblasts expressed COL11A2 and Sp7, upregulated COL11A2 promoter activity and endogenous gene expression when Sp1, Sp3, or Sp7 were overexpressed, and downregulated them when Sp1, Sp3, or Sp7 were selectively depressed. The results establish that Sp1 proteins regulate COL11A2 transcription by binding to its proximal promoter and directly interacting with CBP, p300, and HDAC.

Biomedical image visualization research using the Visible Human Datasets.

The practice of medicine and conduct of research in major segments of the biologic sciences have always relied on visualizations to study the relationship of anatomic structure to biologic function. Traditionally, these visualizations have either been direct, via vivisection and postmortem examination, or have required extensive mental reconstruction. The revolutionary capabilities of 3-D and 4-D medical imaging modalities, together with computer reconstruction and rendering of multidimensional medical and histological volume image data, obviate the need for physical dissection or abstract assembly. The availability of the Visible Human Datasets from the National Library of Medicine, coupled with the development of advanced computer algorithms to accurately and rapidly process, segment, register, measure, and display high resolution 3-D images, has provided a rich opportunity to help advance these important new imaging, visualization, and analysis methodologies from scientific theory to clinical practice.

Fusion of green fluorescent protein to the C-terminus of granulysin alters its intracellular localization in comparison to the native molecule.

The engineering of green fluorescent protein (GFP) fusion constructs in order to visibly tag a protein of interest has become a commonly used cell biology technique. Although caveats to this approach are obvious, literature reports in which the chimeric molecule behaves differently than the native molecule are scant. This brief report describes one such case. Granulysin, a small lytic and antimicrobial protein produced by cytotoxic lymphocytes, traffics to the regulated secretory system and is subsequently released from cells upon proper stimulus. In an attempt to elucidate mechanisms by which it accumulates in and is released from cytolytic granules, GFP was fused to the C-terminus of granulysin and expressed in an NK cell line. A control construct expressing the native protein was similarly expressed. The data demonstrate that, while the fusion protein is expressed and secreted, its subcellular localization is altered in comparison to native granulysin. Thus, the addition of GFP to the C-terminus of granulysin obscures the signal(s) that cytotoxic lymphocytes use to sort it to the regulated secretory pathway despite its normal biosynthesis and secretion. This example is offered as a cautionary account for other researchers who contemplate using this technology.

A human antibody that promotes remyelination enters the CNS and decreases lesion load as detected by T2-weighted spinal cord MRI in a virus-induced murine model of MS.

The human monoclonal antibody rHIgM22 enhances remyelination following spinal cord demyelination in a virus-induced murine model of multiple sclerosis. Using three-dimensional T2-weighted in vivo spinal cord magnetic resonance imaging (MRI), we have therefore assessed the extent of spinal cord demyelination, before and after 5 weeks of treatment with rHIgM22, to determine whether antibody enhanced remyelination can be detected by MRI. A significant decrease was seen in T2 high signal lesion volume following antibody treatment. Histologic examination of the spinal cord tissue reveals that this decrease in lesion volume correlates with antibody promoted remyelination. To show that rHIgM22 enters the spinal cord and colocalizes with demyelinating lesions, we used ultrasmall superparamagnetic iron oxide particle (USPIO)-labeled antibodies. This may be considered as additional evidence to the hypothesis that rHIgM22 promotes remyelination by local effects in the lesions, likely by binding to CNS cells. The reduction in high signal T2-weighted lesion volume may be an important outcome measure in future clinical trials in humans.

Regulation of ionomycin-mediated granule release from rat basophil leukemia cells.

Cross-linking the high affinity IgE receptor on the rat basophil leukemia clone 2H3 (RBL-2H3) cell line, an vitro model for mast cell signaling, results in granule release. A great deal of research has focused on the earliest steps in this signaling cascade resulting in models which include the participation of lyn, syk, phospholipase C (PLC), protein kinase C (PKC) and intracellular calcium mobilization. In an effort to look at pathways downstream of calcium mobilization, ionomycin-mediated granule release was studied. The kinase inhibitors PP1 (src family), GF109203X (PKC), PD98059 (MEK1/2), and U0126 (MEK1/2) substantially inhibited ionomycin-mediated granule release, while the p38 kinase inhibitor SB203580 did not. Both p38 and erk were phosphorylated upon ionomycin treatment, but only extracellular regulated kinase (erk) activation was completely inhibited by PP1 treatment and partially inhibited by the MEK inhibitors, thus, correlating with the granule release data. Interestingly, while GF109203X alone had no affect on erk activation, combining it with U0126 completely blocked this response. This suggests the existence an alternate pathway for erk activation that is MEK independent and PKC dependent. Experiments in which ionomycin and PP1 were titrated (independently) demonstrated a correlation between erk phosphorylation and granule release, implicating erk in a PP1-inhibitable pathway operating downstream of calcium and controlling mast cell degranulation.