High Signal Changes Research Articles

An unusual case of rapidly progressed cervical compression myelopathy caused by overnight inappropriate usage of Smartphone device

A 38-year-old man was healthy before presenting to our clinic with pain and marked weakness in the right upper extremity. He stated that the symptoms developed the day after he accidentally fell asleep while playing with his Smartphone half-lying on his back with two thick pillows supporting his upper back. Physical examination revealed significant increase in deep tendon reflexes in the lower extremities and clonus. Hoffman’s sign was positive in the left upper extremity. Magnetic resonance image showed high signal change on T2-weighted images of the left spinal cord at the C4-5 level, which was indicative of compression myelopathy.

High speed FPGA-based data acquisition system

An application that involves high speed signal changes at input side makes it very important to have a high speed Data Acquisition without loss of any data. This paper discusses FPGA design architecture programed by VHDL firmware which involves high speed Analog to digital converter (ADC) with sampling rate of 80 mega samples per second, Direct Memory Access (DMA) programed in such a way which transfers data without loss of single data sample and high speed Dual Data Rate 3 (DDR3) SDRAM to store digitized data for further manipulations. It also describes data-rate, and speed achieved to transfer data and plot a graph of digital value which shows there is no loss of data.

Time course of osteoporotic vertebral fractures by magnetic resonance imaging using a simple classification: a multicenter prospective cohort study.

Magnetic resonance imaging (MRI) is useful in diagnosing osteoporotic vertebral fractures (OVFs). This study investigated the time course of OVFs by MRI using a simple classification. This multicenter cohort study was performed from 2012 to 2015. Consecutive patients with ≤2-week-old OVFs were enrolled in 11 institutions. MRI was performed at enrollment and at 1-, 3-, 6-, and 12-month follow-up. Signal changes on T1-weighted imaging (T1WI), T2WI, and short τ inversion recovery (STIR) were classified according to signal intensity. Height and angular motion of vertebral bodies were also measured. The 6-month follow-up was completed by 153 patients. At enrollment, fractured vertebrae signal changes were 43% diffuse and 57% confined low on T1WI; on T2WI, 56, 24, and 5% were confined low, high, and diffuse low, respectively; on STIR, 100% were high. On T1WI, diffuse low remained most common (90% at 1month and 60% at 3months) until 6 and 12months, when most were confined low (54 and 52%, respectively). On T2WI, confined low remained most common (decreasing to 41% at 12months). On STIR, high signal change was shown in 98, 87, and 64% at 3, 6, and 12months, respectively. At 3, 6, and 12months, diffuse low signal change was associated with significantly lower vertebral height, and high signal change was associated with significantly greater angular motion. MRI signal changes were associated with the compression degree and angular motion of fractured vertebrae. This classification showed sufficient reliability in categorizing MRI findings of OVFs.

Predicting delayed union in osteoporotic vertebral fractures with consecutive magnetic resonance imaging in the acute phase: a multicenter cohort study.

The purpose of the present study is to determine predictive radiological findings for delayed union by magnetic resonance imaging (MRI) and plain X-rays at two time points in the acute phase of OVFs. This multicenter cohort study was performed from 2012 to 2015. A total of 218 consecutive patients with OVFs ≤2weeks old were enrolled. MRIs and plain X-rays were performed at the time of enrollment and at 1- and 6-month follow-ups. Signal changes on T1-weighted imaging (T1WI) were classified as diffuse low-, confined low-, or no-signal change; those on T2WI were classified as high (similar to the intensity of cerebrospinal fluid), confined low-, diffuse low-, or no-signal change. The angular motion of the fractured vertebral body was measured with X-rays. A total of 153 patients completed the 6-month follow-up. A high-signal change on T2WI was most useful in predicting delayed union. Sensitivity, specificity, and positive predictive values were 53.3, 87.8, and 51.6% at enrollment and 65.5, 84.8, and 51.4% at the 1-month follow-up, respectively. The positive predictive value increased to 62.5% with observation of high- or diffuse low-signal changes at both enrollment and the 1-month follow-up. The cutoff value of vertebral motion was 5 degrees. Sensitivity and specificity at enrollment were 52.4 and 74.1%, respectively. This study demonstrated the radiological factors predicting delayed union after an OVF. T2 high-signal changes showed the strongest association with delayed union. Consecutive MRIs were particularly useful as a differential tool to predict delayed union following OVFs.

How Different Are the Patients With Bilateral Hippocampal Sclerosis From the Unilateral Ones Clinically?

There is a lack of knowledge on consecutive patients with epilepsy associated with bilateral hippocampal sclerosis (BHS). We aimed to investigate the differentiating features of BHS in comparison with unilateral HS (UHS). We investigated our database for patients with epilepsy fulfilling the major magnetic resonance imaging criteria for BHS; namely, presence of bilateral atrophy and high signal changes on T2 and FLAIR series in the hippocampi. UHS patients seen in past 2 years were included as the control group. Clinical, EEG, and other laboratory findings, data on treatment response and epilepsy surgery were investigated from their files. A total of 124 patients (31 with BHS and 93 with UHS; 49 right-sided and 44 left-sided) were included. We found that 16.1% of the BHS and 18.3% of the UHS groups were not drug-refractory. A binary logistic regression analysis performed with significant clinical features disclosed that history of febrile status epilepticus, mental retardation, and status epilepticus were statistically more common in BHS group. Moreover, diagnosis of psychosis established by an experienced psychiatrist and slowing of the EEG background activity were both found significantly more frequent in BHS. 66.67% of the operated BHS patients showed benefit from epilepsy surgery. BHS is a heterogeneous group, showing significant differences such as increased frequencies of mental retardation, status epilepticus, febrile status epilepticus and psychosis, in comparison to UHS. In all, 16.1% of the BHS cases showed a benign course similar to the UHS group and some patients with drug-resistant epilepsy may show benefit from epilepsy surgery.

The Prevalence of High-Intensity Zone in Symptomatic Patients and Its Correlation with the Disc Degeneration and Segmental Motion

Introduction The high intensity zone (HIZ) represents a high signal change on lumbar spine T2 MRI images. HIZ has been involved in disc degeneration and its presence was associated with inflammation and vascular granular tissue within the annulus fibrosus. Aim of our study was to investigate the HIZ prevalence, its relationship with disc degeneration and the effect on lumbar segmental motion using kinetic magnetic resonance imaging (kMRI). Material and Methods kMRI images of 353 symptomatic patients were analyzed. Data including age, gender, and radiologic assessments based on neutral images including disc degeneration grade of all lumbar spine units from L1/2 to L5/S1 and the presence of HIZ were recorded for all the patients. Demographics and disc degeneration were used for calculating HIZ prevalence. Dynamic flexion and extension images from 168 patients were used for segmental motion comparison between the discs with HIZ and without HIZ. Patients with isthmic or degenerative spondylolisthesis grade 2 or higher, Modic disc or Schmorl's node were excluded due to the potential effect on lumbar kinematics. We used chi-square test and multivariate logistic regression for our statistical analysis. Results Among 353 patients, 107 had HIZ in at least one lumbar disc. The overall HIZ prevalence was the highest in age group 40–49 years of age, followed by 50–59 years irrespectively of disc level. The HIZ prevalence was the highest in grade IV degenerative discs, followed by grade III degenerative discs. For L4/5 segment, HIZ prevalence was the highest in age group 50–59 years and disc degeneration grade IV. For L5/S1 segment, HIZ prevalence was the highest in age group 40–49 years and disc degeneration grade III. The multivariate logistic regression model indicated that the age groups (30–39 and 40–49 years), levels (L4/5 and L5/S1) and disc degeneration grades (III and V) were risk factors for HIZ. The segmental angular motion was signicantly greater in discs with HIZ than those without HIZ on L4/5 and L5/S1. However, the differences were reduced to insignificant when adjusted for disc degeneration grade. Conclusion HIZ prevalence was the highest in the middle age patients (30–39 and 40–49 years) and in the moderately degenerated discs (III and IV). The lower prevalence was observed in the older patients and grade V degenerative discs. The possible reason of increased segmental angular motion at L4/5 and L5/S1 discs with HIZ may be due to the moderate disc degeneration than HIZ itself.

Compression Myelopathy due to Proliferative Changes around C2 Pars Defects without Instability.

We report a case with compression myelopathy due to proliferative changes around the C2 pars defects without instability. A 69-year-old man presented with progressive clumsy hands and spastic gait. Plain radiographs showed bilateral spondylolysis (pars defects) at C2 and fusion between C2 and C3 spinous processes. Dynamic views revealed mobility through the pars defects, but there was no apparent instability. Computed tomography showed proliferative changes at the pars defects, which protruded into spinal canal. On magnetic resonance imaging, the spinal cord was compressed and intramedullary high signal change was found. A diagnosis of compression myelopathy due to proliferative changes around the C2 pars defects was made. We performed posterior decompression. Postoperatively, symptoms have been alleviated and images revealed sufficient decompression and no apparent instability. In patients with the cervical spondylolysis, myelopathy caused by instability or slippage have been periodically reported. The present case involving C2 spondylolysis is extremely rare.

White Matter Change Revealed by Diffusion Tensor Imaging in Gliomas.

BackgroundTumor-related white matter change is detected at late stages with magnetic resonance imaging (MRI), when mass effect or prominent edema is present. We analyzed if diffusion tensor imaging (DTI) white matter change earlier than conventional MRI.MethodsTwenty-six patients with gliomas (World Health Organization grade II, 5; grade III, 12; and grade IV, 9) within 2 cm from the posterior limb of the internal capsule (IC) were studied. Fifteen normal adults were enrolled as controls. Fluid attenuation inversion recovery MRI showed a high signal change at the posterior limb of the IC (HSIC) in 9 patients with grade III or IV gliomas. We classified the gliomas as WHO grade II (gliomas II), grade III or IV without HSIC [gliomas III/IV(-)] and grade III or IV with HSIC [gliomas III/IV(+)], as an indicator of the increase in the severity of the white matter changes. Fractional anisotropy (FA) and apparent diffusion coefficients (ADC) were calculated for the pyramidal tract. Tumor progression along pyramidal tract was evaluated by follow-up MRI in 16 patients at 40±18 months.ResultsFA showed no significant difference between gliomas II and control (p=0.694), but was lower in gliomas III/IV(-) and gliomas III/IV(+) (p<0.001). ADCs were higher in gliomas II, gliomas III/IV(-) and gliomas III/IV(+) than control (p<0.001). Tumor progression was detected in 2/16 patients.ConclusionDTI detected white matter changes that appeared to be normal in MRI. ADC changed even in low grade glioma, indicating ADC may be a better parameter for the early detection of white matter change.

Adrenoleukodystrophy: Diffusion MRI findings

An 8-year-old boy with laboratory evidence of adrenal insufficiency, and an established diagnosis of X-linked adrenoleukodystrophy was referred to our institution for a follow-up magnetic resonance imaging (MRI) examination. Besides T1 and T2-weighted sequences, a diffusion MRI protocol was added. The “trace” sequence, a single-shot, spin-echo, echo-planar imaging sequence was used, which averages the data from the three (x, y, and z) gradients and which provides automatically generated apparent diffusion coefficient (ADC) maps. The acquisition time was 22 sec with TR = 5700 msec, and TE = 139 msec, and slice thickness was 5 mm. On diffusion MRI b = 1000 sec/mm images revealed high-signal changes similar to that seen in cases of restricted diffusion pattern (Fig. 1a). However, the ADC maps revealed that an elevated diffusion pattern was present in the necrotic regions (2.06 and 1.60 × 10−3 mm/sec). The ADC value of the central necrotic zone was higher (2.06× 10−3 mm/sec) compared to that of the peripheral necrotic zone (1.60 × 10−3 mm/sec), and that of the intermediate zone of active demyelination was lower (1.14 × 10−3 mm/sec) (Fig. 1b). These values were higher than the ADC values of the normal regions of the brain parenchyma.

Effect of Functional Group and Surface Charge of PEG and Dextran-Coated USPIO as a Contrast Agent in MRI on Relaxivity Constant

The challenges in molecular imaging are focused on the development of novel contrast agents with much lower relaxation times. Ultrasmall superparamagnetic iron oxide nanoparticles known as USPIO have been used for a variety of applications such as imaging of cancer, apoptosis, and hyperthermia providing higher signal changes based on $$T_{2}^{*}$$ weighted susceptibility effects. Although many studies had been performed on USPIO there is still a lack of data on the effects of the physicochemical properties of these nanoparticles (NP) such as hydrodynamic size, surface charge and type of functional groups, which may alter the relaxivity of these NPs. The aim of this study was to evaluate the effect of different functional groups and surface charges of PEGylated and dextran-coated NPs on their magnetic properties. All relaxometry studies were performed using a 3-T magnetic resonance imaging. Our results showed that the impact of charge on magnetic properties is much higher than that of coating thickness. In this respect, particles with positive surface charges showed higher r 2/r 1 ratios.

Diagnosis and treatment of skipping amphi-laceration of disco-ligamentous complex combined with hyperextension injury to the cervical spinal cord

Objective To explore the diagnosis and treatment of skipping amphi-laceration of disco-ligamentous complex (DLC) combined with hyperextension injury to the cervical spinal cord. Methods From January 2008 to December 2012, 17 cases of skipping amphi-laceration of DLC combined with hyperextension injury to the cervical spinal cord were surgically treated at our department. They were 15 men and 2 women, 21 to 57 years of age (average, 36. 3 years). Cervical spine MRI and dynamic flexion-extension lateral radiographs were performed in all patients preoperatively. Injured spinal cord segments were determined according to the plane of spinal cord injury and high signal changes in spinal cord on MRI. Segments of DLC laceration were evaluated according to cervical spine MRI and subaxial cervical stability on radiographs preoperatively. The neurological functions were graded according to the American Spinal Injury Association (ASIA) scale (version 2000) at preoperation, 3, 6 and 12 months postoperatively. The ASIA motor scores (AMS) and sensory scores (ASS) were analyzed statistically. Instrument failure and bony fusion were observed by follow-up radiographs. Results The 17 cases were followed up for an average of 28 months (from 12 to 42 months). The AMS and ASS at all postoperative time points were significantly better than those at preoperation in all patients ( P < 0. 05). Moreover, the AMS and ASS significantly improved as the follow-up time increased, with a significant difference between postoperative time points ( P < 0. 05). There was no failure of instrumentation and bony fusion was observed in all cases of bone grafting. Conclusions The skipping amphi-laceration of DLC combined with hyperextension injury to the cervical spinal cord is likely to be missed in diagnosis. The surgical procedures include decompression of the main spinal cord segment with hyperextension injury and DLC laceration and stability reconstruction of the lacerated DLC segment at the other end. Key words: Cervical vertebrae; Spinal cord; Injury; Disco-ligamentous complex

Delayed neurological deterioration with an unknown cause subsequent to surgery for intraspinal meningiomas.

Delayed neurological deterioration in the absence of direct cord insult following surgical decompression is rare, but severe post-operative complication occurs in chronically compressive spinal disorders. In the present study, the clinical medical records and radiological findings of 10 patients who underwent surgical removal of intraspinal meningiomas and then experienced delayed post-operative neurological deterioration were reviewed. The cases are presented with consideration of the possible underlying mechanisms. There were five male and five female patients, with a mean age of 46.8 years. The mean duration of illness from the onset of symptoms to diagnosis was 42.8 months. Seven tumors were located in the thoracic region and three in the cervical region of the spine. The tumors compressed the cord severely and gross total removal was achieved in all cases. Immediately subsequent to the surgery, all patients were able to move all extremities, but the onset of the neurological deterioration occurred at post-operative hours 3-8 in all cases (mean, 5 h post-surgery). In four cases, radiological examination revealed an area of high signal changes intrinsic to the cord on T2-weighted images, but without residual compression. The mean follow-up period was 49.6 months. Nine patients reported a marked recovery in status compared with the pre-operative presentation during the several weeks to months following surgery. The surgical removal of intraspinal meningiomas may lead to delayed and severe neurological deterioration in the post-operative period in the absence of direct mechanical cord insult. Ischemia-reperfusion injury may be one potential etiology of this deterioration. Recognition of the neurological deficit following surgical excision of intraspinal meningiomas may improve pre-operative patient counseling and merits further study for the determination of the precise pathophysiology.

Development and validation of a risk prediction model for tracheostomy in acute traumatic cervical spinal cord injury patients

Tracheostomy may become indispensable for patients with acute traumatic cervical spinal cord injuries. However, the early prediction of a tracheostomy is often difficult. Previous prediction models using the pulmonary function test (PFT) have limitations because some severely injured patients could not provide acceptable PFT results. We aim to develop an alternative model for predicting tracheostomy using accessible data obtained from the bedside. Clinical, neurological and radiological data from 345 consecutive patients with acute tetraplegia were retrospectively reviewed. We applied multiple logistic regression analysis (MLRA) and classification and regression tree (CART) analysis to develop the prediction model for tracheostomy. By train-test cross-validation, we used the sensitivity, specificity, area under the receiver operating characteristics curve (AUC) and correction rate to evaluate the performance of these models. According to the American Spinal Injury Association (ASIA) standards, an admission ASIA motor score (AAMS) ≤ 22, ASIA grade A and presence of respiratory complications were identified as independent predictors of tracheostomy by both models. The model derived by CART suggested that the highest signal change (HSC) in the spinal cord on magnetic resonance imaging (MRI) also affected a patient's requirement for a tracheostomy, while MLRA demonstrated that tracheostomy was also influenced by the presence of an ASIA grade B injury. The CART model had a sensitivity of 73.7%, specificity of 89.7%, AUC of 0.909 and overall correction rate of 87.3%. The sensitivity, specificity, AUC and correction rate of the MLRA model were 81.8, 86.4, 0.889 and 85.7%, respectively. We suggest using the CART model in clinical applications. Patients with AAMS ≤ 1 exhibit an increased likelihood of requiring a tracheostomy. For patients with an AAMS in the range of 2-22, surgeons should consider giving these patients a tracheostomy once respiratory complications occur. Surgeons should be cautious to give a tracheostomy to patients with an AAMS ≥ 23, if the patient experiences an incomplete spinal cord injury and the HSC in the spinal cord is at C3 level or lower based on MRI. For other patients, close observation is necessary; generally, patients with complete SCI might require a tracheostomy more frequently.

Rapid detection of microorganisms based on active and passive modes of QCM.

Label-free immunosensors are well suited for detection of microorganisms because of their fast response and reasonable sensitivity comparable to infection doses of common pathogens. Active (lever oscillator and frequency counter) and passive (impedance analyzer) modes of quartz crystal microbalance (QCM) were used and compared for rapid detection of three strains of E. coli. Different approaches for antibody immobilization were compared, the immobilization of reduced antibody using Sulfo‐SMCC was most effective achieving the limit of detection (LOD) 8 × 104 CFU·mL−1 in 10 min. For the passive mode, software evaluating impedance characteristics in real-time was developed and used. Almost the same results were achieved using both active and passive modes confirming that the sensor properties are not limited by the frequency evaluation method but mainly by affinity of the antibody. Furthermore, reference measurements were done using surface plasmon resonance. Effect of condition of cells on signal was observed showing that cells ruptured by ultrasonication provided slightly higher signal changes than intact microbes.

Using Click Chemistry to Tune the Properties and the Fluorescence Response Mechanism of Structurally Similar Probes for Metal Ions

AbstractFour cyclam‐based fluorescent molecular probes were prepared using “click” chemistry and investigated to determine the effect of the triazole connectivity and fluorophore substitution on the photophysical properties and metal‐ion response mechanism. The fluorescence of the ligands is turned on in the presence of ZnII but varies in intensity depending on the solvent; the highest signal changes are found in MeCN. Complexation with CuII leads to fluorescence quenching, but only in the aqueous solvent, in which the triazole is involved in coordination of the metal. The length of the pendant triazole arm influences the ligand field around pentacoordinate CuII to yield a distorted square‐planar coordination geometry in the ligands with an ethylene linker. The quantum yield (QY) of the emission intensity can be tuned by the triazole substitution, thereby resulting in increases in QY of more than one order of magnitude (ligand 1 versus 3). Changing the fluorophore opens up alternative radiative processes, thus leading to phosphorescence‐like behavior in coumarin probe 2. Steady‐state fluorescence emission spectra of the free ligands and their respective CuII complexes in a “glass environment” reveal two different inherent fluorescence quenching mechanisms. In the free ligands an electron‐transfer deactivates the excited chromophore, whereas in the CuII complexes it is energy transfer that results in complete quenching of the emission of the ligands.

The association of combination of disc degeneration, end plate signal change, and Schmorl node with low back pain in a large population study: the Wakayama Spine Study

Background contextDisc degeneration (DD) reportedly causes low back pain (LBP) and is often observed concomitantly with end plate signal change (ESC) and/or Schmorl node (SN) on magnetic resonance imaging. PurposeThe purpose of this study was to examine the association between DD and LBP, considering ESC and/or SN presence, in a large population study. Study design/settingCross-sectional population-based study in two regions of Japan. Patient sampleOf 1,011 possible participants, data from 975 participants (324 men, 651 women; mean age, 66.4 years; range, 21–97 years) were included. Outcome measuresPrevalence of DD, ESC, and SN alone and in combination in the lumbar region and the association of these prevalence levels with LBP. MethodsSagittal T2-weighted images were used to assess the intervertebral spaces between L1–L2 and L5–S1. Disc degeneration was classified using the Pfirrmann classification system (grades 4 and 5 indicated degeneration); ESC was defined as a diffuse high signal change along either area of the end plate, and SN was defined as a small well-defined herniation pit with a surrounding wall of hypointense signal. Logistic regression analysis was used to determine the odds ratios (ORs) and confidence intervals (CIs) for LBP in the presence of radiographic changes in the lumbar region and at each lumbar intervertebral level, compared with patients without radiographic change, after adjusting for age, body mass index, and sex. ResultsThe prevalence of lumbar structural findings was as follows: DD alone, 30.4%; ESC alone, 0.8%; SN alone, 1.5%; DD and ESC, 26.6%; DD and SN, 12.3%; and DD, ESC, and SN, 19.1%. These lumbar structural findings were significantly associated with LBP in the lumbar region overall, as follows: DD, ESC, and SN, OR 2.17, 95% CI 1.2–3.9; L1–L2, OR 6.00, 95% CI 1.9–26.6; L4–L5, OR 2.56, 95% CI 1.4–4.9; and L5–S1, OR 2.81, 95% CI 1.1–2.3. The combination of DD and ESC was significantly associated with LBP as follows: L3–L4, OR 2.43, 95% CI 1.5–4.0; L4–L5, OR 1.82, 95% CI 1.2–2.8; and L5–S1, OR 1.60, 95% CI 1.1–2.3. ConclusionsOur data suggest that DD alone is not associated with LBP. By contrast, the combination of DD and ESC was highly associated with LBP.

Hyperextension injury of the C1–C2 cervical spine with neurologic deficits: horizontal splitting fracture of the C1 arch

A 45-year-old man was admitted to the emergency department of another medical center after a fall from a height of 7 m, accompanied with neck extension. He was transferred to our hospital 2 days after the injury. He was in a quadriplegic state, with Grade 0 motor power of the upper extremity and Frankel classification Grade B on physical examination. The lateral view of a cervical computed tomography (CT) image revealed a Type II odontoid fracture and a splitting fracture of the C1 anterior and posterior arches. A normal atlantodens interval was revealed (Fig. 1, Left). A Jefferson fracture was observed on the axial view of a CT image. An oblique occipital condyle fracture accompanied with an odontoid fracture was revealed on a coronal CT image (Fig. 1, Right). Magnetic resonance imaging revealed a signal change in the spinal cord at the C2 level, and no rupture of the transverse ligament was observed (Fig. 2). The patient underwent an operation 3 days after the injury considering a diagnosis of central cord syndrome with occipital condyle, Jefferson, and odontoid fractures. Excellent reduction and fixation of the dens were confirmed on a postoperative plain radiograph (Fig. 3). Postoperative magnetic resonance imaging performed 5 days after the operation demonstrated the expansion and high density of the signal change in comparison with that before the operation (Fig. 4). Neurologic symptoms of the upper extremity indicated that sensory deficit recovered gradually with time. Fig. 2A T2-weighted axial magnetic resonance image of the cervical spine showing no significant transverse ligament rupture, and a T2-weighted sagittal magnetic resonance image of the cervical spine showing a preoperative high-signal change of the spinal cord at the C2 level. View Large Image Figure Viewer Download Hi-res image Fig. 3A lateral radiograph of the cervical spine showing bicortical screw placement for the C2 odontoid fracture. View Large Image Figure Viewer Download Hi-res image Fig. 4A T2-weighted sagittal magnetic resonance image of the cervical spine taken 5 days after the operation showing an extended and higher signal change than that observed on the preoperative image. View Large Image Figure Viewer Download Hi-res image

IT'S NO LAUGHING MATTER

Background Nitrous oxide abuse is on the increase and can cause neurological dysfunction by inactivation of Vitamin B12 resulting in manifestations such as Sub-acute combined degeneration of spinal cord and Peripheral neuropathy. Case report We report two young patients who presented to emergency neurology clinic with progressive dysasthesia. Both had history of smoking, alcohol and had inhaled nitrous oxide from whipped cream canisters. Examination of both patients revealed unremarkable cranial nerves but case 1 had sluggish reflexes in the lower limbs with thoracic sensory level while case 2 had mild weakness distally in the upper limbs, global areflexia and cervical sensory level. MRI spine in both cases showed posterior cervico-thoracic cord high signal change. Case 1 had low Vitamin B12 and high Methylmalonic acid levels. Case 2 declined blood tests but had a demyelinating sensorimotor neuropathy on nerve conduction studies. Both patients were advised on abstinence from nitrous oxide and treated with Vitamin B12 supplementation. Conclusion Neurological sequelae of Nitrous oxide toxicity are under-recognised. It is a common recreational drug and its use should be specifically sought in young patients presenting with signs of a myelo-neuropathy.

Can MRI predict subsequent pseudarthrosis resulting from osteoporotic thoracolumbar vertebral fractures?

The purpose of this study was to assess the ability of short inversion time inversion-recovery (STIR) in magnetic resonance imaging for predicting the prognosis of osteoporotic vertebral fractures. We analyzed 63 vertebrae of 56 patients who had osteoporotic vertebral fracture (Th10-L2) prospectively. Image finding of a homogeneous high signal change on a fractured vertebra was evaluated and all vertebrae were divided into "homogenous high signal change group" or "non-homogenous high signal change group". On the other hand, image finding of linear black signal area was evaluated and all vertebrae were divided into "linear black signal area group" or "non-linear black signal area group". Sixteen and 24 vertebrae were included in the homogenous high signal change group or the linear black signal area group, respectively. The 16 homogenous high signal change cases did not result in non-union, and 47 non-homogenous high signal change cases resulted in 14 non-unions, a significant difference. Twenty-four linear black signal area and 39 non-linear black signal area cases resulted in 10, and 4 non-unions, respectively, also a significant difference. The kyphosis progression rate of the linear black signal area group (mean 35%) was significantly higher than that of non-linear black signal area group (mean 23%). The visual analog scale of back pain of the linear black signal area group (mean 35 mm) was significantly higher than that of the non-linear black signal area group (mean 23 mm). STIR was useful for predicting bone union, kyphosis, and back pain in patients with osteoporotic vertebral fracture.

Modeling distinct imaging hemodynamics early after TBI: the relationship between signal amplitude and connectivity.

Over the past decade, fMRI studies of cognitive change following traumatic brain injury (TBI) have investigated blood oxygen level dependent (BOLD) activity during working memory (WM) performance in individuals in early and chronic phases of recovery. Recently, BOLD fMRI work has largely shifted to focus on WM and resting functional connectivity following TBI. However, fundamental questions in WM remain. Specifically, the effects of injury on the basic relationships between local and interregional functional neuroimaging signals during WM processing early following moderate to severe TBI have not been examined. This study employs a mixed effects model to examine prefrontal cortex and parietal lobe signal change during a WM task, the n-back, and whether there is covariance between regions of high amplitude signal change, (synchrony of elicited activity (SEA) very early following TBI. We also examined whether signal change and SEA differentially predict performance during WM. Overall, percent signal change in the right prefrontal cortex (rPFC) was and important predictor of both reaction time (RT) and SEA in early TBI and matched controls. Right prefrontal cortex (rPFC) percent signal change positively predicted SEA within and between persons regardless of injury status, suggesting that the link between these neurodynamic processes in WM-activated regions remains unaffected even very early after TBI. Additionally, rPFC activity was positively related to RT within and between persons in both groups. Right parietal (rPAR) activity was negatively related to RT within subjects in both groups. Thus, the local signal intensity of the rPFC in TBI appears to be a critical property of network functioning and performance in WM processing and may be a precursor to recruitment observed in chronic samples. The present results suggest that as much research moves toward large scale functional connectivity modeling, it will be essential to develop integrated models of how local and distant neurodynamics promote WM performance after TBI.