Feed-forward neural networks using cerebral MR spectroscopy and DTI might predict neurodevelopmental outcome in preterm neonates.

OBJECTIVES: We aimed to evaluate the ability of feed-forward neural networks (fNNs) to predict the neurodevelopmental outcome (NDO) of very preterm neonates (VPIs) at 12 months corrected age by using biomarkers of cerebral MR proton spectroscopy (1H-MRS) and diffusion tensor imaging (DTI) at term-equivalent age (TEA). METHODS: In this prospective study, 300 VPIs born before 32 gestational weeks received an MRI scan at TEA between September 2013 and December 2017. Due to missing or poor-quality spectroscopy data and missing neurodevelopmental tests, 173 VPIs were excluded. Data sets consisting of 103 and 115 VPIs were considered for prediction of motor and cognitive developmental delay, respectively. Five metabolite ratios and two DTI characteristics in six different areas of the brain were evaluated. A feature selection algorithm was developed for receiving a subset of characteristics prevalent for the VPIs with a developmental delay. Finally, the predictors were constructed employing multiple fNNs and fourfold cross-validation. RESULTS: By employing the constructed fNN predictors, we were able to predict cognitive delays of VPIs with 85.7% sensitivity, 100% specificity, 100% positive predictive value (PPV) and 99.1% negative predictive value (NPV). For the prediction of motor delay, we achieved a sensitivity of 76.9%, a specificity of 98.9%, a PPV of 90.9% and an NPV of 96.7%. CONCLUSION: FNNs might be able to predict motor and cognitive development of VPIs at 12 months corrected age when employing biomarkers of cerebral 1H-MRS and DTI quantified at TEA. KEY POINTS: • A feed-forward neuronal network is a promising tool for outcome prediction in premature infants. • Cerebral proton magnetic resonance spectroscopy and diffusion tensor imaging can be used for the construction of early prognostic biomarkers. • Premature infants that would most benefit from early intervention services can be spotted at the time of optimal neuroplasticity.

Preoperative prediction of language function by diffusion tensor imaging.

For surgery of eloquent tumors in language areas, the accepted gold standard is functional mapping through direct cortical stimulation (DCS) in awake patients. Ever since, neuroscientists are searching for reliable noninvasive detection of function in the human brain, with variable success. The potential of diffusion tensor imaging (DTI) in combination with computational cortical parcellation to predict functional areas in language eloquent tumors has not been assessed so far. We present a proof-of-concept report involving awake surgery for a temporodorsal tumor. Postoperatively, the imaging was extensively studied and a predictive value of multimodal MR imaging for the possible extent of resection was analyzed. After resection using DCS, the extent of resection and functional outcome were correlated with the processed imaging. Preoperative imaging of our patient was taken to compute the lesion volume as a seed for tractography (DTI) and combined with a tractography of the entire hemisphere. For better spatial resolution, an elastic image fusion was performed to correct the distortion of DTI data. After subtotal resection and imaging analysis, the status of the superior part of the lesion could be identified and predicted as functional cortex. There was a strong correlation between the tumor remnant during surgery and the imaging parameters of DTI connectivity of the eloquent tissue. A combination of complex DTI processing may be able to predict function in a patient suffering eloquent brain tumors and thus allow estimation of extent of resection.

Residual Thromboembolic Material in Cerebral Arteries after Endovascular Stroke Therapy Can Be Identified by Dual-Energy CT.

BACKGROUND AND PURPOSE: Dual-energy CT features the opportunity to differentiate among up to 3 different materials because the absorption of x-rays depends on the applied tube voltage and the atomic number of the material. For example, it is possible to distinguish between blood-brain barrier disruption and an intracerebral hemorrhage following treatment for a stroke. The aim of this study was to evaluate whether dual-energy CT is capable of distinguishing intra-arterial contrast agent from residually clotted vessels immediately after endovascular stroke therapy. MATERIALS AND METHODS: Sixteen patients (9 women, 7 men; mean age, 63.6 ± 13.09 years) were examined. Measurements were made on the postinterventional dual-energy CT virtual noncontrast, iodine map, and "weighted" brain window (weighted dual-energy) series. Postinterventional conventional angiography was used as the criterion standard method. RESULTS: A residual clot was found in 10 patients. On the virtual noncontrast series, the Hounsfield attenuation of the clotted arteries was higher than that in the corresponding perfused contralateral arteries (53.72 ± 9.42 HU versus 41.64 ± 7.87 HU; P < .05). The latter had higher absorption values on the weighted dual-energy series than on the virtual noncontrast series (49.37 ± 7.44 HU versus 41.64 ± 7.87 HU; P < .05). The sensitivity for the detection of a residual clot was 90%; the specificity was 83.3%, and the accuracy was 87.5%. Interrater agreement was good (κ = 0.733). CONCLUSIONS: Dual-energy CT may be valuable in the detection of clot persistence or early re-thrombosis without the necessity of additional contrast administration. However, its relevance for the prediction of outcomes remains to be determined in further studies.

Dual energy CT myelography after lumbar osteosynthesis.

PURPOSE: The purpose of this study was to evaluate the benefits of CT myelography in the DE technique in patients with lumbar osteosynthesis. MATERIALS AND METHODS: In 30 patients a DE-CT scan of the spine with tube voltages of 80 kV and 140 kV was performed and a virtual monochromatic series of 120 kV was generated after intrathecal contrast injection. The impact of metal artifacts on the spinal canal and the spinal foramina was evaluated. The visualization of nerve roots was compared between a VRT series of the dural sac and conventional myelography. RESULTS: With tube voltages of 140 kV, the artifacts were least pronounced. As no overlay disturbance was present, VRT visualization of the nerve roots was more reliable than conventional myelography. CONCLUSION: In patients after osteosynthesis, CT in the DE technique provides minimal artifact disturbance using a tube voltage of 140 kV. "Virtual myelography" seems to be superior to conventional myelography for the evaluation of nerve roots. This could reduce additional conventional radiography, may shorten the entire examination and radiation time and diminish unnecessary painful movements for the patient.

7 Tesla MRI demonstrates vascular pathology in Balo's concentric sclerosis.

Baló's concentric sclerosis (BCS) is an inflammatory demyelinating disease related to multiple sclerosis; its underlying pathology remains unclear. At 7 T MRI in a 19-year-old female BCS patient, microhaemorrhages and ectatic veins were found in T2 hyperintense regions, features which have not been previously reported in conjunction with BCS, and these findings may support the view that vascular pathology plays a role in BCS. MRS data suggest that neuron loss and lipid turnover still took place months after a remission. Plasma exchange was effective in treating a relapse with severe motor deficits, and the off-label use of natalizumab was successful in maintaining remission in this patient.

Magnetic resonance imaging of cranial nerves at 7 Tesla.

PURPOSE: The aim of this study was to demonstrate the feasibility of cranial nerve (CN II-XII) imaging with 7 Tesla magnetic resonance imaging (MRI). METHODS: In this study four sequences were evaluated in three healthy volunteers using magnetization preparation rapid gradient echo (MPRAGE), constructive interference in steady state (CISS), true fast imaging with steady state precession (TrueFISP) and proton density (PD) T2-weighted turbo spin echo (TSE) sequences. RESULTS: It was found that MPRAGE did not always provide sufficient contrast to delineate in particular small CNs but displayed an overall good identification rate. The T2 sequence was not able to adequately differentiate the small CNs but showed a very good contrast between nerves and cerebrospinal fluid (CSF). As at lower magnetic fields steady state sequences displayed a high identification rate of all CNs in the axial plane but CISS suffered from susceptibility and pulsation artifacts, furthermore it was limited as no parallel imaging could be performed. The TrueFISP technique was reliable in identifying most CNs although suffering from banding artifacts. CONCLUSIONS: The TrueFISP sequence showed superior spatial resolution and contrast in comparison to the other sequences for imaging of CNs at 7 T.

Complete endovascular occlusion of a cranial dural fistula using a venous "to the point" approach.

BACKGROUND AND OBJECT: Cranial dural arteriovenous fistulas are commonly treated using an endovascular method. In comparison to intracerebral arteriovenous malformations, it is important to reach the venous part of these malformations to maintain a complete occlusion. Therefore, often the venous side is totally occluded using coils and∕or glue. PATIENT AND METHODS: We describe a patient with an initially Type IIab (Cognard classification) left occipital cranial fistula. The patient suffered from an intense pulsate tinnitus. Therefore, the first embolization was performed using an approach via the dilated left middle meningeal artery using Onyx. The shunt of the fistula was reduced significantly but total occlusion was impossible. Therefore, the venous approach was used. Over a guiding catheter in the sigmoid sinus, the venous side of the fistula could be reached with a microcatheter. This part of the fistula was then completely occluded using coated and bare coils, without occluding the adjacent sinus. Control angiography of all previous feeders showed a complete occlusion of the fistula (used classification: Cognard). RESULTS: The fistula was entirely occluded. The patient's outcome was excellent. The patient did not develop any symptoms and no complication occurred due to the treatment. CONCLUSIONS: Direct occlusion of the venous part of an arteriovenous cranial fistula can be an option before an occlusion of the sinus has to be performed. This approach can lead to reduction of risk during the endovascular procedure and risk reduction in long-term follow-up.

Indication, technique and benefit of intraoperative spinal digital subtraction angiography with a new setting in a patient with spinal arteriovenous malformation.

BACKGROUND AND OBJECT: A new setting of intraoperative spinal angiography within an angiography suite is presented. PATIENT AND METHODS: In a patient with thoracic arteriovenous malformation, the resection was performed within an angiography suite. Therefore a long sheath was applied, which remained sterile during the procedure and allowed a catheter to be introduced which is navigated into the noted segmental artery for contrast injection. RESULTS: Digital subtraction angiography was performed prior to and after the resection at the AVM in order to visualize recent feeders and to ensure the complete occlusion. CONCLUSIONS: This method leads to an increased image quality and a shorter operation time in comparison to an angiography within an operating room.

Predictors of self-reported problems of confusion among the aged.

Responses to questions on the 1984 Supplement on Aging to the National Health Interview Survey (NHIS) about the experience of personal confusion revealed that two-thirds of those interviewed reported never having an episode of confusion during the preceding year. Of those who reported episodes, fewer than one in five said they were happening with increased frequency. The many meanings of confusion found in the literature prompted a modest local study of what respondents understood by the term when asked the NHIS questions. Of those who admitted occasional confusion, almost two-thirds gave definitions that included memory loss or forgetfulness. Consequently, increased frequency of memory problems and difficulty in remembering were included with other variables in the analyses to identify significant predictors. They emerged the single best predictors of how often a respondent reported getting confused. Others were change in health status, number of functional limitations, educational attainment, and vision problems.

Correlates of self-reported everyday memory problems.

Using the 1984 Supplement on Aging to the National Health Interview Survey, this study examined the prevalence and correlates of self-reported everyday memory problems in a sample of persons aged 55 and older (N = 14,783). Fifteen percent of the respondents reported having had trouble remembering things frequently during the past year, but 26 percent indicated having had no trouble. Of those reporting any problems, only 18 percent said the problem was happening with increasing frequency. Sex, age, educational attainment, subjective health status, perceived changes in health status, number of functional limitations, and vision and hearing impairments were examined in bivariate and multivariate analyses to identify significant predictors of self-reported memory problems.