Hong-Wei Zhou

Diagnosis of posterior reversible encephalopathy syndrome: does DWI help?

We read with interest Ruth Williams’ report on the use of telemedicine and information technologies in neurology. We provide present and future thoughts and concerns about this new technology that might help underserved areas with no neurologists. First, we believe that in the immediate future, telemedicine has great potential to electronically bridge the gap between underserved areas and centres that have specialty neurologists, without having to increase the overall supply of neurologists. Teleneurology can provide instant neurologist input via secure internet-based video interaction, without specialists or patients having to travel long distances. Furthermore, the supply of neurologists is not expected to substantially increase to match the expected rise in age-related neurological disease in the ageing population. The eff ect of teleneurology might be greatest in acute stroke—a medical emergency—especially in view of the cost-eff ectiveness of thrombolytic therapy, which can now be given up to 4·5 h after onset of stroke. However, what happens when the telemedicine operator does not possess the requisite clinical skills in neurology to diagnose and manage the patient, or when the virtual consultative modality does not result in an adequately reliable and valid examination? In the USA, there are now commercial robots with specialised arms that not only function as electronic stethoscopes and otoscopes, but that can also focus on various parts of the neurological examination—eg, extraocular muscle movements. Even though a patient can be examined remotely by a robot, it is the knowledge, experience, and judgment of the interpreting physician that results in accurate diagnoses, appropriate clinical management, and reasonable predictions of prognosis. Although the technological advances are fascinating, the most crucial element of any telemedicine interaction is still the human connection between a patient who needs help and a physician who cares. An unskilled telemedicine operator is no more capable of properly treating the patient from a distance than is a similarly untrained live physician on-site. This concept is especially important in neurology—a specialty in which raw clinical data and fi ndings are generally not equivalent to diagnoses. There is a growing number of anecdotal reports in the USA about the use of commercially available robots with remote, non-neurologist operators in place of neurologists for both acute and non-acute diagnosis and management. Similarly, the audio–video telemedicine consultative modality, which has been well studied in acute stroke, is being broadly extended into many other neurological subspecialty arenas without suffi ciently supportive evidence. The resulting diagnoses have not always been correct, and the treatments not always appropriate. In some cases, existing contracts between a hospital and a robot service have superseded the use of an on-site consulting neurologist, even when one was readily available. Teleneurology can successfully be an adjunct to, an extension of, or even a replacement for, on-site clinical neurology, but only when directed by qualifi ed neurologists. Unfortunately, commercial incentives could potentially override and interfere with the professional obligations to the patient.

Diagnosis of non-acute cerebral venous thrombosis with 3D T1-weighted black blood sequence at 3 T

BACKGROUNDnWe investigated the value of 3D T1-weighted SPACE (Sampling Perfection with Application optimized Contrast using different angle Evolutions, a 3D fast spin echo black blood sequence) in the diagnosis of cerebral venous thrombosis (CVT).nnnMETHODSnWe prospectively included 31 consecutive patients who were suspected as having a CVT within one month of disease onset. The reference standard of CVT diagnosis was based on all of the conventional imaging tests (including susceptibility weighted imaging), clinical information, and prognosis information.nnnRESULTSnThe final diagnosis of the CVT was made for 14 patients including 60 venous segments. The median time between disease onset and the examination with magnetic resonance was 12.5days with a range of 8 to 27days. The diagnosis results of susceptibility weighted imaging plus magnetic resonance venography (MRV) were consistent with the final diagnosis. The sensibility/specificity for T1 SPACE were 100%/100% per patient and 96.7%/100% per segment. The area under the curve based on patient for T1 SPACE was higher than that of standard magnetic resonance imaging (MRI) (1.0 vs. 0.80, P=0.02) and standard MRI plus MRV (1.0 vs. 0.91, P=0.14). The area under the curve based on segment for T1 SPACE was significant higher than that of standard MRI (0.98 vs. 0.81, P<0.001) and standard MRI plus MRV (0.98 vs. 0.87, P<0.001).nnnCONCLUSIONSn3D T1 SPACE offered excellent visualization of the thrombus as evident high signal intensity with an acceptable acquisition time. The use of 3D T1 SPACE may improve the accuracy of subacute CVT diagnosis.

Progressive Facial Hemiatrophy Revisited: A Role for Sympathetic Dysfunction

OBJECTIVEnTo report a case of progressive facial hemiatrophy with unusual features of contralateral brain atrophy and transcranial Doppler ultrasound evidence of autonomic dysfunction.nnnDESIGNnCase report.nnnSETTINGnA teaching hospital.nnnPATIENTnA 63-year-old man who presented with a 10-year history of progressive right-sided facial atrophy and recent facial pain.nnnRESULTSnBrain magnetic resonance imaging revealed left frontoparietal atrophy. Transcranial Doppler ultrasound demonstrated evidence of autonomic dysfunction ipsilateral to brain atrophy.nnnCONCLUSIONnThis case expands the spectrum of findings in progressive facial hemiatrophy to include contralateral brain atrophy and suggests that sympathetic dysfunction might play a pathogenic role in progressive facial hemiatrophy.

Vessel wall differences between middle cerebral artery and basilar artery plaques on magnetic resonance imaging.

A recent study showed that posterior circulation plaques have a greater capacity for positive remodeling in a non-Asian population. We aimed to investigate if the features of plaques in the middle cerebral artery (MCA) were different from those in the basilar artery (BA) in a northern Chinese population. We retrospectively analysed the records of 71 consecutive patients with acute ischemic stroke. All patients had at least one MCA or BA plaque with early or mild (<50% stenosis) atherosclerosis identified using vessel wall magnetic resonance imaging. The remodeling ratio, eccentricity index, and plaque range were compared between MCA and BA plaques using multilevel analysis. A total of 101 plaques were included. There were 70 plaques located in the MCA and 31 plaques located in the BA. The features of non-advanced atherosclerotic plaques did not differ between the MCA and BA when accounting for the degree of stenosis or plaque burden in a northern Chinese population. Symptomatic plaques were associated with a higher eccentricity index and smaller plaque range than asymptomatic plaques under the same plaque burden. Further studies are warranted to investigate the progression of atherosclerosis in different intracranial arteries.

3D T1-weighted black blood sequence at 3.0 Tesla for the diagnosis of cervical artery dissection

Objective We aimed to investigate the value of three-dimensional (3D) T1 volumetric isotropic turbo spin echo acquisition (VISTA) in the diagnosis of cervical artery dissection (CAD). Methods We prospectively included patients who were suspected as having a CAD within 1u2005month of onset. For T1 VISTA, the diagnosis of the dissection was based on the presence of intramural high-signal, intimal flap, double lumen and aneurysmal dilation. The final diagnosis of dissection was based on the clinical history, physical examination, and all of the imaging tests. Results A total of 46 patients were included in this study. The final diagnosis of CAD was made for 21 patients. Diagnosis of dissection was made for 20 of the 21 patients after assessing T1 VISTA. A definitive diagnosis of dissection was not made for 5 patients (including 3 patients with digital subtraction angiography) before the T1 VISTA examination. The sensitivity and specificity for T1 VISTA were 95.2% (95% CI, 76.2% to 99.9%) and 100% (95% CI, 86.3% to 100%), respectively. The agreement between the two researchers for T1 VISTA for diagnosis of CAD was very good (k=0.91). For patients without acute artery occlusion, all of them had a definite conclusion with or without dissection by T1 VISTA (n=29). However, for 17 patients with acute artery occlusion, the possibility of dissection could not be excluded for 6 of them by T1 VISTA (p=0.001). Conclusions 3D T1 VISTA at 3.0 Tesla was useful in the diagnosis of acute CAD. However, for some patients with total occlusion of the artery without typical imaging features of dissection, the unequivocal distinction between intramural haematoma and intraluminal thrombus may be not adequate by T1 VISTA alone. Future studies should investigate whether a follow-up scan, a contrast-enhanced imaging or an optimal VISTA technique could be useful.

Intracranial hypotension and PRES

Pugliese and colleagues [1] reported a female case presenting worsening of the headache and tonic–clonic seizures 7 days after epidural analgesia for a caesarean section. They proposed their diagnoses of intracranial hypotension (IH), secondary to the inadvertent dural puncture, and posterior reversible encephalopathy syndrome (PRES), which evolved from IH, based on MRI findings as well as clinical manifestations. The case is intriguing in that it helps to enrich the etiology of PRES, while we would like to raise some questions concerning the diagnosis of this case. As regards the diagnosis of IH, the gold standard is lumbar puncture to detect the intracranial pressure. However, it was absent in this case study. In this regard, their diagnosis of IH mainly based on the presence of pachimeningeal thickening, enhancing after contrast administration is not convincing enough. The enhancement might be due to increased permeability or damage of blood–brain barrier resulting from tonic–clonic seizures of the patient [2]. In particular, Fig. 1a in their article is apparently not a T2-weighted image. Probably, it is a fluidattenuated inversion recovery (FLAIR) image. As far as PRES is concerned, its diagnosis and association with IH should be made with caution, since relationship between IH and PRES has not been reported in literature. Although the authors suggested two different but related mechanisms involved in IH that may lead to PRES [1], etiologies of PRES including hypertension (61%), cytotoxic medications (19%), sepsis (7%), preeclampsia or eclampsia (6%), and multiple organ dysfunction (1%) [3] should be carefully ruled out from this case. In summary, this is an interesting case suggestive of IH and PRES by clinical and MRI findings, although the potential relationship between IH and PRES still needs further investigation.

Xenon-enhanced CT assessment of cerebral blood flow in stroke-in-progress patients with unilateral internal carotid artery or middle cerebral artery stenosis

Carotid or cerebral artery stenosis resulting in low perfusion is a major cause of ischemic stroke. Understanding the unique hemodynamic features in each patient undergoing a stroke-in-progress (SIP) and the correlation between progression and cerebral blood flow (CBF) status would help in the diagnosis and treatment of individual patients. We used xenon-enhanced CT (Xe-CT) to examine cerebral perfusion in patients with or without SIP (30 patients/group), recruited from October 2009 to October 2010. Only SIP patients with unilateral stenosis in the internal or middle cerebral artery were recruited. The occurrence of watershed infarction was higher in the SIP group than in the non-SIP group (P <0.05). In the SIP group, larger hypoperfused areas were found around the lesions than in the non-SIP group. In the SIP group, the CBF values in the ipsilateral areas were significantly lower than those in corresponding regions on the contralateral side. CBF values in the contralateral hemisphere were significantly lower in the SIP group than in the non-SIP group. In SIP patients, infarctions were surrounded by larger hypoperfused areas than in non-SIP patients. These larger hypoperfused areas may result in pathological damage to the brain that is responsible for the progression of stroke.

Magnetic resonance imaging of Guillain-Barré syndrome

Dear Editor,We read with great interest the article by Yikilmaz andcolleagues, which described features of spinal magneticresonance imaging (MRI) in children with Guillain-Barresyndrome (GBS) and investigated the correlation betweenMRI characteristics and the clinical/laboratory examinations[2]. Their findings are intriguing in that MRI appearspromising as a supplementary modality to conventionaldiagnostic methods of GBS. However, we have someconcerns about this study.In this study, a control group seems missing, althoughthe authors mentioned “All patients and the control groupwere scanned with a 1.5-T clinical MR scanner” in thePatients and Methods only. As a consequence, thespecificity of contrast enhancement in spinal MRI, whichmay differentiate GBS from other diseases with/withoutnerve root involvement, is unavailable. This pitfall of thestudy design might limit the merits of their findings.Therefore, the conclusion that MRI can be used as asupplementary diagnostic modality to clinical and labora-tory findings of GBS should be further confirmed bycontrolled studies in the future.Another concern arising from the research is theenrollment of the study subjects. Since the subjects wereretrospectively selected from patients who were hospitalizedin their center with the diagnosis of GBS between 2005 and2010,weareeagertoknowhowtheauthorscouldaccumulateupto40GBScasesthatunderwentacontrast-enhancedspinalMRI. It is well established that MRI contributes to thediagnosis of GBS by demonstrating anterior and posteriorintrathechal spinal nerve roots [1]. However, the use of MRIespecially contrast-enhanced spinal MRI in GBS is currentlyuncommon. Considering the relatively low incidence of GBSin children and that this was a single-center study, we suspectthat the authors designed and conducted this investigation inaprospectiveway.References

The Impact of Variational Primary Collaterals on Cerebral Autoregulation

The influence of the anterior and posterior communicating artery (ACoA and PCoA) on dynamic cerebral autoregulation (dCA) is largely unknown. In this study, we aimed to test whether substantial differences in collateral anatomy were associated with differences in dCA in two common types of stenosis according to digital subtraction angiography (DSA): either isolated basal artery and/or bilateral vertebral arteries severe stenosis/occlusion (group 1; group 1A: with bilateral PCoAs; and group 1B: without bilateral PCoAs), or isolated unilateral internal carotid artery severe stenosis/occlusion (group 2; group 2A: without ACoA and with PCoA; group 2B: with ACoA and without PCoAs; and group 2C: without both ACoA and PCoA). The dCA was calculated by transfer function analysis (a mathematical model), and was evaluated in middle cerebral artery (MCA) and/or posterior cerebral artery (PCA). Of a total of 231 non-acute phase ischemic stroke patients who received both dCA assessment and DSA in our lab between 2014 and 2017, 51 patients met inclusion criteria based on the presence or absence of ACoA or PCoA, including 21 patients in the group 1, and 30 patients in the group 2. There were no significant differences in gender, age, and mean blood pressure between group 1A and group 1B, and among group 2A, group 2B, and group 2C. In group 1, the PCA phase difference values (autoregulatory parameter) were significantly higher in the subgroup with patent PCoAs, compared to those without. In group 2, the MCA phase difference values were higher in the subgroup with patent ACoA, compared to those without. This pilot study found that the cross-flow of the ACoA/PCoA to the affected area compensates for compromised dCA in the affected area, which suggests an important role of the ACoA/PCoA in stabilizing cerebral blood flow.

Recurrent chondrosarcoma of the larynx: A case report and literature review

BackgroundLaryngeal chondrosarcoma (LCS) is a rare laryngeal tumor that most commonly originates from the cricoid cartilage. The current trend for treatment of low-grade LCS is function-sparing surgical option with negative margins. Case summaryWe reported here a case of a 63-year-old male patient with a 3-month history of progressive hoarseness and throat pain. The patient had undergone surgical resection of a laryngeal mass 2 years prior. A supracricoid partial laryngectomy was performed this time. Histological examination supported the diagnosis of low-grade chondrosarcoma. Three years later, the radiological and clinical findings showed no evidence of recurrence. ConclusionCurrently, total laryngectomy is preferred for patients with recurrent low-grade LCS. However, the literature review and our case suggest that a second function-preserving procedure may be a reasonable choice for recurrent LCS.