Presence Of High Signal Intensity Research Articles

The Resolution of Kaplan Fiber Injuries Is Observed in a Majority of Cases at 9 Months After Acute Primary Anterior Cruciate Ligament Reconstruction: A Radiological Study

Background: The natural history of Kaplan fiber (KF) injuries after acute primary anterior cruciate ligament (ACL) reconstruction (ACLR) remains unknown. Purpose/Hypothesis: The purpose of this study was to evaluate the temporal change in the magnetic resonance imaging (MRI) appearance of the KF complex after acute primary ACLR. It was hypothesized that KF injuries would resolve with time. Study Design: Case series; Level of evidence, 4. Methods: A retrospective MRI analysis was conducted on 89 patients with ACL-injured knees to assess the change in the radiological appearance of KFs after primary ACLR. Patients who had undergone index MRI and ACLR within 90 days of the injury and further MRI at 9 months after surgery were included. Diagnostic criteria to identify radiological evidence of a KF injury and its subsequent resolution were applied, including the presence of high signal intensity on fluid-sensitive sequences, which is indicative of a pathological process radiologically. The proximity of KFs to the femoral cortical suspensory device (CSD) was noted on MRI scans and quantified in millimeters. Results: A KF injury was identified in 30.3% (27/89) of patients, with isolated high signal intensity observed in an additional 18.0% (16/89). At 9 months, MRI evidence of the reconstitution of the KF complex was found in 51.9% (14/27) of patients, with persistent discontinuity in the remaining patients (13/27). All patients (16/16) with isolated high signal intensity had complete resolution on repeat MRI scans. KF thickening was observed in 26.1% (12/46) of patients with previously healthy KFs and in 25.0% (4/16) with isolated high signal intensity. The CSD was positioned in close proximity (≤6 mm) to the center of the KF attachment in 61.8% (55/89) of patients, and this was associated with increased rates of KF thickening. Conclusion: The KF injury resolved radiologically in over half of the patients at 9 months after acute primary ACLR. High signal intensity in the region of the KFs on index MRI scans resolved in all cases, with evidence of residual KF thickening in only one-quarter of cases on repeat MRI scans, equivalent to the rate in those with healthy KFs. As such, it is not advisable to use high signal intensity on preoperative MRI scans as the sole criterion for the diagnosis of a KF injury. The position of the CSD after ACLR was intimately related to the KF attachment in the majority of patients, which was associated with KF thickening on postoperative MRI scans.

Association of ultra-early diffusion-weighted magnetic resonance imaging with neurological outcomes after out-of-hospital cardiac arrest

BackgroundThis study aimed to investigate the association between ultra-early (within 6 h after return of spontaneous circulation [ROSC]) brain diffusion-weighted magnetic resonance imaging (DW-MRI) and neurological outcomes in comatose survivors after out-of-hospital cardiac arrest.MethodsWe conducted a registry-based observational study from May 2018 to February 2022 at a Chungnam national university hospital in Daejeon, Korea. Presence of high-signal intensity (HSI) (PHSI) was defined as a HSI on DW-MRI with corresponding hypoattenuation on the apparent diffusion coefficient map irrespective of volume after hypoxic ischemic brain injury; absence of HSI was defined as AHSI. The primary outcome was the dichotomized cerebral performance category (CPC) at 6 months, defined as good (CPC 1–2) or poor (CPC 3–5).ResultsOf the 110 patients (30 women [27.3%]; median (interquartile range [IQR]) age, 58 [38–69] years), 48 (43.6%) had a good neurological outcome, time from ROSC to MRI scan was 2.8 h (IQR 2.0–4.0 h), and the PHSI on DW-MRI was observed in 46 (41.8%) patients. No patients in the PHSI group had a good neurological outcome compared with 48 (75%) patients in the AHSI group. In the AHSI group, cerebrospinal fluid (CSF) neuron-specific enolase (NSE) levels were significantly lower in the group with good neurological outcome compared to the group with poor neurological outcome (20.1 [14.4–30.7] ng/mL vs. 84.3 [32.4–167.0] ng/mL, P < 0.001). The area under the curve for PHSI on DW-MRI was 0.87 (95% confidence interval [CI] 0.80–0.93), and the specificity and sensitivity for predicting a poor neurological outcome were 100% (95% CI 91.2%–100%) and 74.2% (95% CI 62.0–83.5%), respectively. A higher sensitivity was observed when CSF NSE levels were combined (88.7% [95% CI 77.1–95.1%]; 100% specificity).ConclusionsIn this cohort study, PHSI findings on ultra-early DW-MRI were associated with poor neurological outcomes 6 months following the cardiac arrest. The combined CSF NSE levels showed higher sensitivity at 100% specificity than on DW-MRI alone. Prospective multicenter studies are required to confirm these results.

Magnetic resonance (MR) for mural nodule detection studying Intraductal papillary mucinous neoplasms (IPMN) of pancreas: Imaging-pathologic correlation

PurposeMagnetic Resonance (MR) is recommended to diagnose Intraductal Papillary Mucinous Neoplasms (IPMN) and in the follow-up of borderline lesions. The purpose of this work is to evaluate the diagnostic accuracy of dynamic MR with Diffusion Weighted Imaging (DWI) in the identification of mural nodules of pancreatic IPMN by using pathological analysis as gold standard. Materials and methodsNinety-one preoperative MR with histopathological diagnosis of IPMN were reviewed by two radiologists. Presence, number and size of mural nodule, signal intensity of the nodule on T1-weighted imaging (T1-WI) after contrast medium administration and on DWI. Inter-observer agreement was evaluated. ResultsSignificant correlation (p < 0.0001) were found for presence of nodules > 5 mm on MR and pathological specimen, size and number of mural nodules evaluated on pathological review and degree of dysplasia, size and number of mural nodules evaluated on MR and tumoral dysplasia, presence of nodule > 5 mm with enhancement after contrast medium administration and hyperintensity on DWI and degree of dysplasia. Interobserver agreement was moderate for the presence of mural nodule (K = 0.56), for the presence of high signal intensity on DWI (K = 0.57) and enhancement of mural nodule (K = 0.58). Apparent Diffusion Coefficient (ADC) map histogram analysis showed a correlation between Entropy of the entire cystic lesion and the degree of dysplasia (p < 0.034). ConclusionsMR with dynamic and DWI sequences was an accurate method for the identification of ≥ 5 mm solid nodules of the IPMNs and correlate with the lesion malignancy. Entropy, calculated from the histogram analysis of the IPMN ADC map, correlated with the lesion dysplasia.

Surgery for Degenerative Cervical Myelopathy: What Really Counts?

Retrospective study (data analysis). The purpose of this study was to assess the role of different factors on postoperative outcome of patients with degenerative cervical myelopathy (DCM). Ongoing degenerative changes of DCM lead to progressive neurological deficits. The optimal timing of surgical treatment is still unclear, especially in patients with mild DCM. Patients with DCM treated in our clinic between 2007 and 2016 were retrospectively analyzed. Pre- and postoperative neurological function was assessed by the modified Japanese Orthopaedic Association Score (mJOA Score) at different stages. The minimum clinically important difference (MCID) was used to evaluate the improvement after surgery. The comorbidities were recorded using the Charlson Comorbidity Index (CCI). Possible associations between age, sex, CCI, preoperative symptoms duration, high signal intensity (SI) on T2-weighted magnetic resonance imaging (MRI) with mJOA Score and MCID were analyzed using univariate analysis and multivariate regression models. Additionally, subgroup analysis was performed according to the severity of DCM (mild: mJOA Score ≥15 points; moderate: mJOA Score of 12-14 points; and severe: mJOA Score <12 points). The mean age of the final cohort (n = 411) was 62.6 years (range: 31-96 years), 36.0% were females. High SI on T2-weighted MRI was detected in 60.3% of the cases. In the multivariate analysis, patients' age (P = 0.005), higher CCI (P = 0.001), and presence of high SI on T2-weighted MRI (P = 0.0005) were associated independently with lower pre- and postoperative mJOA Score and postoperative MCID. Subgroup analysis revealed age and high SI on T2-weighted MRI as predictors of pre- and postoperative mJOA. However, symptom duration did not influence neurological outcome according to the severity of DCM. Surgery for DCM leads to significant functional improvement. However, better outcome was observed in younger individuals with lower CCI and absence of radiographic myelopathy signs. Therefore, DCM surgery, particularly before occurrence of high SI on MRI, seems to be essential for postoperative functional improvement regardless the above-mentioned confounders.Level of Evidence: 3.

Does Combining Biomarkers and Brain Images Provide Improved Prognostic Predictive Performance for Out-Of-Hospital Cardiac Arrest Survivors before Target Temperature Management?

We examined whether combining biomarkers measurements and brain images early after the return of spontaneous circulation improves prognostic performance compared with the use of either biomarkers or brain images for patients with cardiac arrest following target temperature management (TTM). This retrospective observational study involved comatose out-of-hospital cardiac arrest survivors. We analyzed neuron-specific enolase levels in serum (NSE) or cerebrospinal fluid (CSF), grey-to-white matter ratio by brain computed tomography, presence of high signal intensity (HSI) in diffusion-weighted imaging (DWI), and voxel-based apparent diffusion coefficient (ADC). Of the 58 patients, 33 (56.9%) had poor neurologic outcomes. CSF NSE levels showed better prognostic performance (area under the curve (AUC) 0.873, 95% confidence interval (CI) 0.749–0.950) than serum NSE levels (AUC 0.792, 95% CI 0.644–0.888). HSI in DWI showed the best prognostic performance (AUC 0.833, 95% CI 0.711–0.919). Combining CSF NSE levels and HSI in DWI had better prognostic performance (AUC 0.925, 95% CI 0.813–0.981) than each individual method, followed by the combination of serum NSE levels and HSI on DWI and that of CSF NSE levels and the percentage of voxels of ADC (AUC 0.901, 95% CI 0.792–0.965; AUC 0.849, 95% CI 0.717–0.935, respectively). Combining CSF/serum NSE levels and HSI in DWI before TTM improved the prognostic performance compared to either each individual method or other combinations.

Radiographic Outcomes of Immobilization using Boston Brace for Pediatric Spondylolysis.

Spondylolysis is a common cause of lower back pain during youth. The aim of this study is to report the bony union rate and risk factors for non-union of the lumbar spondylolysis of pediatric patients treated with a rigid thoracolumbosacral orthosis (Boston brace). A retrospective review of 68 children (mean age = 13.9 years) treated for spondylolysis with a thoracolumbosacral orthosis. Patient charts and imaging studies were evaluated to identify the bony union rate of the spondylolysis after a minimum of 3 months of immobilization (mean = 4.2 months). Laterality, grade, level, and presence of high signal intensity in the magnetic resonance imaging were evaluated as prognostic factors. Sixty-eight patients presented with 110 defects. Of them, 46 (42%) were incomplete fractures, 38 (35%) complete fractures, and 26 (24%) pseudoarthrosis. Of these defects, 38 (82.6%), 11 (28.9%), and 0 (0.0%) had bony union at the end of the treatment (p < 0.001). Unilateral defects healed significantly better than bilateral ones (relative risk = 1.71, 95% confidence interval = 1.16-2.54, 17/26 (65%) vs 32/84 (38%), p = 0.014). High signal intensity in the magnetic resonance images before the treatment predicted healing (relative risk = 13.24, 95% confidence interval = 1.93-91.01, 48/87 (55%) vs 1/24 (4.3%), p < 0.001). The level of the spondylolysis (L5 vs above L5) did not affect the healing rate. The union rates of spondylolysis with a thoracolumbosacral orthosis were similar as compared to earlier studies done with a low thoracolumbosacral orthosis. The grade of the defect, laterality, and presence of high signal intensity increased the probability of bony union. A high thoracolumbosacral orthosis (underarm) does not seem to improve the healing rate of pediatric spondylolysis defects.

Asymptomatic moderate carotid artery stenosis with intraplaque hemorrhage: Progression of degree of stenosis and new ischemic stroke

Carotid intraplaque hemorrhage (IPH) plays a critical role in the progression of carotid atherosclerotic disease. IPH was associated with high intensity signal (HIS) in the plaque on Maximum intensity projection (MIP) images from routine three dimensional magnetic resonance imaging (3D-TOF MRA). The aim of this study was to evaluate the relationships among HIS, new ipsilateral ischemic stroke and a progression rate in carotid plaques with moderate stenosis. We included 45 carotid plaques with moderate stenosis (50%–69%) in 45 patients who could be followed more than 12 months. Carotid IPH was defined as the presence of HIS on 3DTOF MRA using the criteria previously we published. We analyzed the relation between the presence of HIS and new ischemic strokes and annual progression rate of carotid stenosis. HIS was present in 21 (47%) carotid arteries. Over a follow-up period of 24 ± 9 months, six ischemic strokes occurred in ipsilateral side. New ipsilateral ischemic stroke occurred more frequently in HIS positive group (P group: 6 of 21, 29%) than negative group (N group: 0 of 24, 0%) (p = 0.017). Annual progression rate of carotid stenosis is significantly higher in P group (+3.35%/year) than N group (−0.02%/year) (p = 0.0026). In multivariate regression analysis, HIS positive was an independent predictor for annual progression rate of carotid stenosis (p = 0.003). Evaluation of HIS in asymptomatic moderate carotid stenosis can potentially provide risk stratification of new ipsilateral ischemic strokes.

New bone formation in the intervertebral joint space in spondyloarthritis: An MRI study

ObjectivesTo study the presence of high signal intensity of the intervertebral disc, syndesmophytes, vertebral corner bridging and transdiscal ankylosis on spinal T1-weighted MR images in spondyloarthritis (SpA). MethodsA retrospective case-control study of whole spine MRI examinations, obtained in 100 patients with axial SpA and in 100 control patients, was performed. All disco-vertebral units (DVUs) were analyzed on T1-weighted MR images for normal or high signal intensity of the intervertebral disc, presence of syndesmophytes, vertebral corner bridging or transdiscal ankylosis and correlated with final diagnosis. Sensitivity, specificity, and positive and negative likelihood ratios were calculated. ResultsIn this study group, intradiscal high signal intensity, vertebral corner bridging and transdiscal ankylosis on T1-weighted MR images of the spine were all highly specific (specificity: 100%) for diagnosis of axial SpA. However, these signs all had low sensitivity (vertebral corner bridging: 15.0%; intradiscal high signal intensity on T1-weighted MR images: 12.0%; transdiscal ankylosis: 8.0%). Syndesmophytes on spinal MRI were observed in 25 patients but had a more limited diagnostic value (sensitivity: 16.0%, specificity: 91.0%). ConclusionsWhen present in a patient with inflammatory back pain, intradiscal high signal intensity on T1-weighted MR images could be a specific and reliable sign of the presence of axial SpA. Vertebral corner bridging and transdiscal ankylosis also show potential as specific and reliable signs of axial SpA. In contrast, syndesmophytes on MRI do not show potential as a specific or reliable sign of axial SpA.

High intensity signal in the plaque on routine 3D-TOF MRA is associated with ischemic stroke in the patients with low-grade carotid stenosis

Background and purposeCarotid artery stenosis is one of the major causes of ischemic strokes. However, degree of stenosis is not always correlated with frequency of ischemic strokes. The aim of this study was to evaluate relationships between high intensity signal (HIS) in the carotid plaques on maximum intensity projection (MIP) images detected by routine three-dimensional time-of-flight magnetic resonance angiography (3D-TOF MRA) and ischemic strokes in the patients with low-grade stenosis. MethodsOne hundred fifty two patients with low-grade carotid artery stenosis (30%–49%) were included. The presence of HIS located in the plaque but having no connection to the lumen in all projections on MIP images of 3D-TOF MRA was defined as HIS-positive using the previously reported criteria. We analyzed the relationship between the presence of HIS and prior ischemic strokes. ResultsPrior ipsilateral ischemic strokes were observed more frequently in HIS-positive group (12 of 56, 21.4%) than HIS-negative group (1 of 96: 1%) (p<0.001). In multivariate logistic regression analysis, the presence of HIS (odds ratio: 31.8, 95% confidential interval (CI): 3.81–264, p=0.001) and hyperlipidemia (odds ratio: 10.45, 95% CI: 1.01–13.4, p=0.048) were independent determinants of prior ischemic strokes after adjustment for age. ConclusionsHIS in plaques on MIP images of 3D-TOF MRA was an independent determinant of prior ischemic strokes.

Comparison of brain computed tomography and diffusion-weighted magnetic resonance imaging to predict early neurologic outcome before target temperature management comatose cardiac arrest survivors

AimWe previously reported that diffusion-weighted magnetic resonance imaging (DW-MRI) could be used to predict neurologic outcomes before targeted temperature management (TTM) after return of spontaneous circulation (ROSC) from cardiac arrest (CA). We compared the efficacy of brain computed tomography (CT) and DW-MRI to predict neurologic outcome before TTM in comatose cardiac arrest survivors. MethodsWe performed a retrospective study of CA patients treated with TTM. The brain CT and DW-MRI were both obtained before TTM. We analysed the grey matter to white matter ratio (GWR) on the brain CT and the presence of high signal intensity on DW-MRI, alone or in combination, to predict poor neurologic outcome (CPC 3–5). ResultsOf 47 comatose CA patients treated with TTM, 39 patients with brain CT and DW-MRI data were included. Median time from the ROSC to the brain CT and DW-MRI was 90min (52–150) and 175min (118–240), respectively. There was no significant difference in predicting poor neurologic outcome between average GWR (area under the curve [AUC] 0.891, sensitivity/specificity 78.8%/100%) and DW-MRI (AUC 0.894, sensitivity/specificity 75.8%/100%) (p=0.963). The combination of average GWR and DW-MRI (AUC 0.939, sensitivity/specificity 87.9%/100%) improved the prediction of poor neurologic outcome rather than each one alone and in other combinations. ConclusionOur preliminary finding suggests that DW-MRI is potentially useful for early prediction of neurologic outcome (i.e., before TTM) in CA patients. The combination of GWR on brain CT and that on DW-MRI, rather than on each modality alone, appears to improve the sensitivity for predicting neurologic outcome after ROSC from CA. Large prospective multicenter studies should be conducted to confirm these results.

Association between duration of coronary occlusion and high-intensity signal on T1-weighted magnetic resonance imaging among patients with angiographic total occlusion

ObjectivesTo evaluate the association between duration of the coronary occlusion and high-intensity signal (HIS) on noncontrast T1-weighted imaging using a 1.5-T magnetic resonance imager among patients with angiographic coronary total occlusion.MethodsThe signal intensity of the coronary target area divided by the signal intensity of the left ventricular muscle near the target area at each site (TMR) was measured. Areas with a TMR >1.0 were defined as HIS. Thirty five lesions from 33 patients were divided into the following three groups: subacute occlusion (up to 3 months; n = 7), short-duration chronic total occlusion (SD-CTO: 3–6 months; n = 9) and long-duration CTO (LD-CTO: ≥6 months; n = 19).ResultsAll subacute occlusion lesions showed a HIS within the occlusion site. Among patients with CTO, the frequency of a HIS within the occlusion site was significantly higher in SD-CTO than in LD-CTO lesions (p = 0.013). In multivariate analyses, only an occlusion duration of less than 6 months was an independent factor associated with the presence of HIS (odds ratio 7.6, 95% CI 1.1–54.5; p = 0.044).ConclusionsThe presence of a HIS in the occlusion site was associated more with SD-CTO than with LD-CTO among patients with CTO.Key Points• All subacute occlusion lesions show a high-intensity signal on T1-weighted imaging.• HIS within occlusion sites is associated with subacute or short-duration total occlusion.• T1-weighted imaging for coronary total occlusion may be useful for intervention strategy.

Abstract TMP33: High Intensity Signal in the Plaque on 3DTOF MRA is Associated With Ischemic Stroke in the Patients With Low Grade Carotid Artery Stenosis

Background: Carotid artery stenosis is one of the major causes of ischemic strokes. However, degree of stenosis is not always correlated with frequency of ischemic strokes. Recently, it was reported that carotid intraplaque hemorrhage (IPH) was associated with accelerated plaque growth, luminal narrowing and development of symptomatic events. Maximum intensity projection (MIP) images are easily reformatted within from 5 minute, routine time-of-flight (TOF) sequences. The aim of this study was to evaluate the relationships between high intensity signal (HIS) in the carotid plaques on MIP images detected by routine three-dimensional TOF magnetic resonance angiography (3D-TOF MRA) and ischemic strokes. Materials and Methods: One hundred fifty two patients with low-grade carotid artery stenosis (North American Symptomatic Carotid Endarterectomy Trial criteria: 30% - 49%) were included. IPH was defined as the presence of HIS in the carotid plaques on MIP images of 3D-TOF MRA using the previously reported criteria. We analyzed the relationship between the presence of HIS in the plaques and prior ischemic strokes defined as ischemic lesions on diffusion weighed images of the brain. Results: HIS in the carotid plaque was present in 56 (37%) of 152 carotid arteries. Prior ipsilateral ischemic strokes were observed more frequently in HIS-positive group (12 of 56, 21.4%) than HIS-negative group (1 of 34: 2.9%) [p&lt;0.001]. In multivariate logistic regression analysis, HIS (Odds ratio: 77.7, 95%CI: 6.4 - 944.0, p&lt;0.001) and diabetes mellitus type 2 (odds ratio: 10.45, 95%CI: 1.6 - 67.9, p=0.014) were independent determinants of prior ischemic strokes after adjustment for age. Conclusions: HIS in the carotid plaques on MIP images of 3D-TOF MRA was an independent determinant of prior ischemic stroke in patients with low-grade carotid artery stenosis, and this finding may provide a reliable risk stratification of future stroke in patients with low-grade carotid artery stenosis.

High intensity zone in lumbar spine and its correlation with disc degeneration.

Purpose; To investigate the prevalence, clinical significance of high intensity zone (HIZ), and associated disc degeneration. Materials and methods; We undertook retrospective analysis of 228 patients, aged from 15 to 55 years, who had undergone magnetic resonance (MR) imaging of lumbar spine in outpatient clinic from 2013 to 2014. HIZ was defined as a presence of high intensity signal in the annulus on T2-weighted images. All HIZ positive discs were classified according to Pfirrmann grading system for presence of disc degeneration. Results; Forty-three patients (18.8%) with 53 intervertebral discs demonstrated HIZ. There was no significant predominance about age and gender for the presence of HIZ. HIZ occurred mainly at L4-5 (43.3%) and L5-S1 (30.2%) levels, infrequently at L3-4 (17%) and rarely at upper levels. The prevalence of disc degenerations with Pfirrmann grade 3, 4, and 5 were significantly higher in HIZ positive patients than in randomly selected 35 HIZ negative patients (64% vs. 46%, respectively). Conclusion; In this study we identified that the presence of HIZ was directly proportional to increased incidence of disc degeneration in remaining lumbar discs. The prevalence of significant degeneration was significantly higher in HIZ positive patient at lower three lumbar levels. J. Med. Invest. 64: 39-42, February, 2017.

The signal intensity of coronary culprit lesions on T1-weighted magnetic resonance imaging is directly correlated with the accumulation of vulnerable morphologies

BackgroundIn the magnetic resonance T1-weighted imaging, some investigators have shown that coronary artery high-intensity signals (HISs) are associated with vulnerable plaque morphology and an increased risk of future cardiac events. Although previous studies used different PMR (the ratio between the signal intensities of coronary plaque and cardiac muscle) cutoff values to detect HIS, the association between PMR itself and plaque morphology has not been fully investigated. Methods and ResultsWe prospectively investigated the association between PMR values and plaque morphology detected by optical coherence tomography in consecutive 106 patients with angina pectoris. The lesions with almost all of the vulnerable features such as lipid-rich, thin-cap fibroatheroma, plaque rupture, thrombus, macrophage infiltrations, intimal vasculature, and absence of calcification had significantly higher PMR; the only exception was the presence of cholesterol crystals. PMR increases linearly with the number of vulnerable features (p<0.0001, Rho=0.504). Stepwise multiple linear regression analysis revealed that the absence of calcification (p=0.0027), and the presence of thrombus (p=0.0071) and intimal vasculature (p=0.019) were independently associated with higher log-transformed PMR. There was a stepwise increase in PMR of the culprit lesions in proportion to the accumulation of the number of adverse plaque characteristics defined as non-calcified plaque, thrombus, and/or intimal vasculature. ConclusionThese results suggest that not only the presence of HIS, but also the elevated PMR itself may be used as a quantitative marker of plaque vulnerability in clinical evaluation.

Prognostic factor analysis after surgical decompression and stabilization for cervical spinal-cord injury

Introduction: Several studies have demonstrated the role of decompression surgery in preventing secondary injury and improving the neurological outcome after spinal cord injury (SCI). We retrospectively analyzed the prognostic factors affecting the outcomes of decompression surgery in patients with SCI.Methods: We performed one-level decompression and fusion surgery on 73 patients with cervical SCI. We classified all patients based on their interval to decompression, sex, age, surgical level, presence of high signal intensity, American Spinal Injury Association Impairment scale (AIS) before surgery, blood pressure at admission, the amount of cord compression, surgical time, estimated blood loss during surgery, and steroid use. We considered an improvement to have occurred if the patient showed an AIS improvement of ≥1 grade.Results: Among the 73 patients with SCI we analyzed, 27 and 35 showed ≥1 grade of AIS improvement immediately and 3 months after surgery, respectively. Using multivariate analysis, the mean arterial blood pressure (MAP) was a significant prognostic factor affecting recovery in the SCI patients during the immediate post-operative period. In the late recovery period at 3 months after surgery, the AIS before surgery and the MAP were significant prognostic factors affecting recovery.Conclusions: Prognostic factors for AIS improvement include the initial neurological status before surgery and hemodynamic MAP at admission. The interval between decompression surgery and trauma does not affect the neurological outcome.

Abstract WP122: Asymptomatic Moderate Carotid Artery Stenosis With Intraplaque Hemorrhage ∼ Progression of Degree of Stenosis and New Ischemic Stroke

Background: Carotid artery stenosis is one of the major causes of ischemic stroke. Carotid intraplaque hemorrhage (IPH) plays a critical role in the progression of carotid atherosclerotic disease. Previous studies showed that IPH was associated with high intensity signal (HIS) on maximum intensity projection (MIP) images from routine three dimensional magnetic resonance imaging (3D-TOF MRA). The aim of this study was to evaluate the relationships among HIS, new ipsilateral ischemic stroke and a progression rate in carotid plaques with moderate stenosis. Materials and Methods: We included 45 carotid plaques with moderate stenosis (50% to 69%) in 45 patients who could be followed more than 12 months. Carotid IPH was defined as the presence of HIS in carotid plaque on MIP image from routine 3DTOF MRA using the criteria previously we published. We analyzed the relation between the presence of HIS in the plaques and new ischemic strokes and annual progression rate of carotid stenosis. Results: HIS in carotid plaque was present in 21 (47%) carotid arteries. Over a follow-up period of 24 ± 9 months, six ischemic strokes occurred ipsilateral to the index carotid artery. New ipsilateral ischemic stroke occurred more frequently in HIS positive group (6 of 21, 29%) than HIS negative group (0 of 24, 0%) (p=0.017). Annual progression rate of carotid stenosis is significantly higher in HIS positive group (+3.35%/year) than HIS negative group (-0.02%/year) (p= 0.0026). In multivariate regression analysis, HIS positive was an independent predictor for annual progression rate of carotid stenosis (p=0.003). Conclusions: HIS in carotid plaques on 3DTOF-MRA MIP images are associated with new ischemic stroke and higher annual progression rate of stenosis. Evaluation of HIS in asymptomatic moderate carotid stenosis can potentially provide risk stratification of new ipsilateral ischemic strokes.

High-Intensity Signal in Carotid Plaque on Routine 3D-TOF-MRA Is a Risk Factor of Ischemic Stroke

Background: Carotid atherosclerotic disease is recognized as an important risk factor for brain ischemic events. However, high-grade stenosis does not always cause ischemic strokes, whereas moderate-grade stenosis may often cause ischemic strokes. It has been reported that there is an association between carotid intraplaque hemorrhage (IPH) and new cerebral ischemic events. The purpose of this study was to elucidate the relationship between high-intensity signals (HIS) on maximum intensity projection (MIP) images from routine 3-dimensional time-of-flight magnetic resonance angiography (3D-TOF-MRA) and prior ischemic strokes in the patients with moderate carotid stenosis. Materials and Methods: Sixty-one patients with moderate carotid artery stenosis (50-69% stenosis based on North American Symptomatic Carotid Endarterectomy Trial criteria) were included. Carotid IPH was defined as the presence of HIS in carotid plaques on MIP images detected by 3D-TOF-MRA using criteria we previously reported. We analyzed the relationship between the presence of HIS in plaques and prior ischemic strokes defined as ischemic lesions on diffusion-weighted brain images. Results: HIS in carotid plaques were present in 27 (44%) of 61 patients. Prior ipsilateral ischemic strokes occurred more frequently in the HIS-positive group than the HIS-negative group (67 vs. 9%, p < 0.001). Furthermore, there were more smokers in the group with ischemic stroke than without it (62 vs. 25%, p = 0.005). In multivariate logistic regression analysis, HIS in carotid plaque (OR 23.4, 95% CI 4.62-118.3, p < 0.001) and smoking (OR 5.44, 95% CI 1.20-24.6, p = 0.028) were independent determinants of prior ischemic strokes after adjustment for age. Conclusions: HIS in carotid plaques on 3D-TOF-MRA MIP images are independent determinants of prior ischemic strokes in patients with moderate carotid artery stenosis, and they can potentially provide a reliable risk stratification of patients with moderate carotid artery stenosis.

Associations between Cerebral Embolism and Carotid Intraplaque Hemorrhage during Protected Carotid Artery Stenting.

Carotid artery stent placement in patients with intraplaque hemorrhage remains controversial because of the incidence of cerebral embolism after the procedure. The purpose of this study is to determine if intraplaque hemorrhage is a significant risk factor for cerebral embolism during carotid artery stent placement. This prospective study assessed 94 consecutive patients with severe carotid stenosis. These patients underwent preprocedural carotid MR imaging and postprocedural DWI after carotid artery stent placement. Intraplaque hemorrhage was defined as the presence of high signal intensity within the carotid plaque that was >200% of the signal from the adjacent muscle on MPRAGE. We then analyzed the incidence of postprocedural ipsilateral ischemic events on DWI and primary outcomes within 30 days of carotid artery stent placement. Forty-three patients (45.7%) had intraplaque hemorrhage on an MPRAGE image. There was no significant difference in the incidence of postprocedural ipsilateral ischemic events and primary outcomes between the intraplaque hemorrhage and non-intraplaque hemorrhage group. However, postprocedural ipsilateral ischemic events were more frequently observed in the symptomatic group (17/41 [41.5%]) than in the asymptomatic group (8/53 [15.1%]; P = .005). Intraplaque hemorrhage was not a significant risk factor for cerebral embolism during carotid artery stent placement in patients with severe carotid stenosis. Symptomatic patients should receive more careful treatment during carotid artery stent placement because of the higher risk of postprocedural ipsilateral ischemic events.

Abstract 140: High Intensity Signals on Mip Images of Carotid Atherosclerotic Plaques Detected by Routine Three Dimensional Magnetic Resonance Angiography Are Associated With Ischemic Strokes

Background: Carotid artery stenosis is one of the major causes of ischemic strokes. Carotid intraplaque hemorrhage (IPH) has been associated with accelerated plaque growth, luminal narrowing and development of symptomatic events. Maximum intensity projection images are easily reformatted from four to five minute, routine, clinical TOF sequences. The aim of this study was to evaluate the relationships between high intensity signal (HIS) in carotid plaques on MIP images detected by routine three dimensional magnetic resonance imaging (3D-TOF MRA) and ischemic strokes. Materials and Methods: Sixty patients with carotid stenosis ≥ 50% (North American Symptomatic Carotid Endarterectomy Trial criteria) were included. Carotid IPH was defined as the presence of HIS in carotid plaques on MIP images detected by 3DTOF MRA using the criteria previously we reported. We analyzed the relation between the presence of HIS in the plaques and prior ischemic strokes defined as ischemic lesions on diffusion weighed images of the brain. Results: HISs in carotid plaque were present in 27 (44%) of 61 carotid arteries in 60 patients. Prior ipsilateral ischemic strokes occurred more frequently in HIS positive group (17 of 27, 63%) than HIS negative group (3 of 34; 9%) [p&lt;0.001]. In multivariate logistic regression analysis, HIS was the only independent predictor of prior ischemic strokes after being adjusted by age, cardiovascular risk factors, degree of stenosis and history of ischemic heart disease [Odds ratio: 23.0 (95%CI: 5.1 - 103.1), p&lt;0.001]. Conclusions: HISs in carotid plaques on 3DTOF-MRA MIP images are the only independent determinant of prior ischemic strokes, and they can potentially provide a reliable risk stratification of carotid plaques.

Diffusion weighted MR imaging of 5-fluorouracil and oxaliplatin-induced leukoencephalopathy

A 55-year-old man treated with 5-fluorouracil and oxaliplatin for advanced sigmoid colon cancer presented with seizures, progressive gait and balance difficulties with frequent falls and slurring of speech. After three cycles of chemotherapy, brain magnetic resonance imaging using diffusion-weighted imaging clearly revealed the presence of high signal intensity in the deep white matter of the bilateral cerebral hemispheres, including the corpus callosum symmetrically. A diagnosis of acute leukoencephalopathy was made based on these findings. His clinical symptoms normalized after the discontinuation of the chemotherapy. Early detection of drug-induced leukoencephalopathy is important as the clinical symptoms can be reversed by early discontinuation of the causative drug. Diffusion-weighted magnetic resonance imaging is a useful modality for the early detection and definitive diagnosis of this characteristic encephalopathy.