1. Chen Z, Zheng Y, Yuan Y, et al. Modic Changes and Disc Degeneration Caused by Inoculation of Propionibacterium acnes inside Intervertebral Discs of Rabbits: A Pilot Study. Biomed Res Int. 2016;2016:9612437. doi:10.1155/2016/9612437.

Wild-type strain of P. acnes isolated from a patient associated with Modic change and disc degeneration was inoculated into the intervertebral discs of rabbits (n=8). S. aureus was injected into the discs to establish a model of discitis as a comparison.  A standard strain of P. acnes was inoculated as the control. MRI and histological change were evaluated. MRI was performed before and every two weeks after the inoculation until the end of follow-up at the eighth week. Both the P. acnes-inoculated and S. aureus-inoculated rabbits showed hyperintense signals at endplates and hypointense signals at nucleus pulposus on T2WI. However, P. acnes only resulted in moderate disc degeneration and endplates rupture in histological examination. They conclude that compared to S. aureus, the pathological change caused by P. acnes would be considered as Modic-I change and disc degeneration rather than a discitis.

They are of the opinion that the presented data satisfied the first, second, and third criteria of Koch’s Postulates and they extrapolate that P. acnes has a strong connection with Modic change and disc degeneration. 3 figures with histopathology.

In case you had forgotten Koch’s postulates:

1. The pathogen must be found in abundance in all organisms suffering from the disease, but should not be found in healthy organisms.
2. The pathogen must be isolated from a diseased host and grown in pure culture.
3. The cultured microorganism should cause the disease when introduced into a healthy organism.
4. The microorganism must be reisolated from the inoculated, diseased experimental host and identified as being identical to the original specific causative agent.

2. Hall SS, Dougherty RF, Reiss AL. Profiles of aberrant white matter microstructure in fragile X syndrome. NeuroImage Clin. 2016;11:133–138. doi:10.1016/j.nicl.2016.01.013.

Fragile X syndrome (FXS) is the most common known inherited form of intellectual disability affecting approximately 1 in 3000 boys and 1 in 5000 girls worldwide. FXS is caused by mutations to the FMR1 gene at locus 27.3 on the long arm of the X chromosome. Excessive methylation of the gene impairs production of Fragile X Mental Retardation Protein (FMRP), a key protein involved in synaptic plasticity and dendritic maturation in the brain. The authors used Automated Fiber-tract Quantification (AFQ) to identify specific regions of aberrant WM microstructure along WM tracts in patients with FXS (20 patients age 10-23 years) that differed from controls (n=20) who were matched on age, IQ and degree of autistic symptoms. They found that fractional anisotropy was significantly increased in the left and right inferior longitudinal fasciculus (ILF), right uncinate fasciculus, and left cingulum hippocampus in individuals with FXS compared to controls. They conclude that FXS results in abnormal WM microstructure in specific regions of the ILF and uncinate fasciculus, most likely caused by inefficient synaptic pruning as a result of decreased or absent Fragile X Mental Retardation Protein.

3 Figures

3. Olsen AL, Miller JJ, Bhattacharyya S, Voinescu PE, Klein JP. Cerebral perfusion in stroke-like migraine attacks after radiation therapy syndrome. Neurology. 2016;86(8):787–789. doi:10.1212/WNL.0000000000002400.

Stroke-like migraine attacks after radiation therapy (SMART) syndrome is characterized by transient, focal neurologic symptoms occurring years after radiation, with focal or regional cortical thickening and enhancement on MRI in the area of brain exposed to radiation. The authors present 2 patients with recurrent attacks of SMART syndrome with increased cerebral blood volume in affected regions (perfusion MRI) and abnormal vascular reactivity (via Doppler US). They conclude that SMART syndrome is associated with regional hyperperfusion preceding both seizures and MRI cortical abnormalities, suggesting a transient period of impaired cerebrovascular autoregulation. These cases are notable because they describe SMART syndrome in patients without intracerebral malignancy, suggesting that cranial radiation alone is sufficient for development. One patient received prophylactic cranial radiation for lung carcinoma 28 years prior, and the other received skull RT for osteosarcoma. Also interesting in the second patient were recurrent episodes of SMART which alternated between the right and left parietal cortices.

1 figure including images from both patients.

4. Purrucker JC, Haas K, Rizos T, et al. Early Clinical and Radiological Course, Management, and Outcome of Intracerebral Hemorrhage Related to New Oral Anticoagulants. JAMA Neurol. 2016;73(2):169. doi:10.1001/jamaneurol.2015.3682.

Non-vitamin K antagonist oral anticoagulants have been shown to be as effective as warfarin for stroke prevention in non-valvular atrial fibrillation (AF) and are associated with reduced risk of intracranial hemorrhage compared with warfarin. Dabigatran, rivaroxaban, apixaban, and edoxaban have been approved in the USA for reducing stroke risk in non-valvular AF. This prospective multicenter observational study evaluates the early clinical and radiological course, acute management, and outcome of ICH related to non–vitamin K antagonist oral anticoagulant (NOAC) use.  38 stroke units across Germany participated enrolling 61 consecutive patients with nontraumatic NOAC-associated ICH, of whom 45 (74%) qualified for hematoma expansion analysis. Hematoma expansion, intraventricular hemorrhage, and reversal of anticoagulation during the acute phase was identified. Recorded were the 3-month functional outcome, factors associated with an unfavorable outcome (modified Rankin Scale score, 3-6), and any new intraventricular extension. Substantial hematoma expansion occurred in 38%. New or increased intraventricular hemorrhage was observed in 18%. Overall mortality was 28% at 3 months. They conclude that non–vitamin K antagonist oral anticoagulant–associated ICH has a high mortality and an unfavorable outcome, and hematoma expansion is frequent.

Still bad to have an intracranial hemorrhage on any type of anticoagulation.

5. Sair HI, Yahyavi-Firouz-Abadi N, Calhoun VD, et al. Presurgical brain mapping of the language network in patients with brain tumors using resting-state fMRI: Comparison with task fMRI. Hum Brain Mapp. 2016;923 (August 2015):913–923. doi:10.1002/hbm.23075.

The authors compared language networks derived from resting-state fMRI (rs-fMRI) with task fMRI in 49 patients with brain tumors who presented for presurgical language mapping and investigated variables that affect rs-fMRI vs task-fMRI concordance. Although there was an excellent language network concordance between rs-fMRI and task-fMRI in some subjects, they demonstrated significant variability across subjects.  They found that the percent root mean square of image intensity (iRMS) was predictive of concordance in three out of four independent component analysis (ICA) orders (ICA30-ICA50) and trended toward significance in the remaining ICA order (ICA20).  They conclude that the high subject level variability in the accuracy of rs-fMRI compared to task-fMRI warrants a view of optimistic caution in determining whether rs-fMRI has the potential to replace or supplement task-fMRI.

3 figures, which really did not help me at all.

6. Uusitalo E, Rantanen M, Kallionpää RA, et al. Distinctive Cancer Associations in Patients with Neurofibromatosis Type 1. J Clin Oncol. 2016. doi:10.1200/JCO.2015.65.3576.

This is a report of a population-based series of patients with NF1 (N = 1,404; 19,076 person-years) linked to incident cancers recorded in the Finnish Cancer Registry and deaths recorded in the national Population Register Centre between 1987 and 2012. In the cancers typically associated wit NF1, malignant peripheral nerve sheath tumors and gliomas, they observed standardized incidence rations (SIRs) of 2,056, and 37 respectively, and standardized mortality ratios (SMRs) of 2,301 and 30 respectively. They found an unequivocally increased risk for breast cancer.  SIR was 11.1 for breast cancer in women with NF1 age <40 years. The 5-year survival of patients with cancer and NF1, excluding nervous tissue cancers, was worse than that of comparable patients with cancers without NF1.  In other words, the estimated cumulative cancer risk in patients with NF1 by age 30 years was as high as 25%, and was 38.8% by age 50 years, whereas the respective percentages in the general Finnish population were 0.8% and 3.9%.

This study 1) confirms the enormously increased relative risk of MPNSTs and demonstrate that MPNSTs in patients with NF1 are fatal tumors, with an SMR of >2,000;  2) NF1-related cancers display an increased SIR and/or SMR include breast cancer, pheochromocytoma, GIST, malignant fibrous histiocytoma, and thyroid cancer and 3) the characteristic of cancer in patients with NF1 is poor survival.

7. van den Wijngaard IR, Wermer MJH, Boiten J, et al. Cortical Venous Filling on Dynamic Computed Tomographic Angiography: A Novel Predictor of Clinical Outcome in Patients with Acute Middle Cerebral Artery Stroke. Stroke. 2016;47(3):762–7. doi:10.1161/STROKEAHA.115.012279.

88 patients with a proximal middle cerebral artery occlusion underwent noncontrast CT and whole-brain CT perfusion/dynamic CT angiography within 9 hours after stroke-onset. For whole-brain CTP/dynamic CTA, a total of 19 volumes were obtained during a duration of 1 minute. Dynamic CTAs were derived from the 320-slice CTP by subtracting the first unenhanced volume of the CTP study from the subsequent contrast-enhanced volumes to ensure that only vessels remained visible. Prognostic value of optimal CVF (maximum opacification of cortical veins) in addition to age, stroke severity, treatment, Alberta Stroke Program Early CT score, cerebral blood flow, and collateral status was assessed with logistic regression and summarized with the area under the curve. They identified a decreased risk of poor outcome in patients with good and fast optimal CVF. They conclude that the combination of extent and velocity of optimal CVF, as assessed with dynamic CT angiography, is useful to identify patients with acute middle cerebral artery stroke at higher risk of poor clinical outcome. 2 Figures.

Also interesting that the vast majority of patients with poor CVF status but good reperfusion, as well as patients with good CVF status but poor reperfusion, had poor clinical outcome at follow-up.

8. Yan S, Chen Q, Xu M, Sun J, Liebeskind DS, Lou M. Thrombus Length Estimation on Delayed Gadolinium-Enhanced T1. Stroke. 2016;47(3):756–61. doi:10.1161/STROKEAHA.115.011401.

In clinical practice, ≈26% – 73% patients with MCA occlusion will not present the susceptibility vessel sign because the clot composition. The authors evaluated a novel technique which is easily implemented to avoid this difficulty.  In 74 patients, the authors prospectively adjusted the order of sequence acquisition to obtain delayed gadolinium–enhanced T1 images (dGE-T1) and assessed the thrombus length on dGE-T1 to evaluate its predictive value for recanalization after IVT. T1 (dGE-T1) can visualize the distal vessels beyond the clot. Using coregistration of the dGE-T1 with TOF-MRA (which only displays the arteries proximal to the occlusion), it is thus possible to estimate the length of thrombus.  Thrombus length measured on dGE-T1 for no recanalization was 6.77 mm, and this yielded a sensitivity of 77.8% and a specificity of 57.9%, and an odds ratio of 4.81. No one achieved recanalization after IVT when length of thrombus exceeded 14 mm on dGE-T1. They conclude that the thrombus length measured on dGE-T1 was independently predictive of MCA recanalization and clinical outcome after IVT.