Initial experience in hybrid PET-MRI for evaluation of refractory focal onset epilepsy.

PURPOSE: We aim to evaluate the utility/improved accuracy of hybrid PET/MR compared to current practice separate 3T MRI and PET-CT imaging for localization of seizure foci. METHOD: In a pilot study, twenty-nine patients undergoing epilepsy surgery evaluation were imaged using PET/MR. This subject group had 29 previous clinical 3T MRI as well as 12 PET-CT studies. Prior clinical PET and MR images were read sequentially while the hybrid PET/MR was concurrently read. RESULTS: The median interval between hybrid PET/MR and prior imaging studies was 5 months (range 1-77 months). In 24 patients, there was no change in the read between the clinical exams and hybrid PET/MR while new anatomical or functional lesions were identified by hybrid PET/MR in 5 patients without significant clinical change. Four new anatomical MR lesions were seen with concordant PET findings. The remaining patient revealed a new abnormal PET lesion without an MR abnormality. All new PET/MR lesions were clinically significant with concordant EEG and/or SPECT results as potential epileptic foci. CONCLUSION: Our initial hybrid PET-MRI experience increased diagnostic yields for detection of potential epileptic lesions. This may be due to the unique advantage of improved co-registration and simultaneous review of both structural and functional data.

Efficacy of safety signals in the epilepsy monitoring unit (EMU): should we worry?

There is little consensus regarding the critical safety measures to prevent harm in epilepsy monitoring units (EMUs). We sought to determine whether the safety signals (SS) triggered during EMU events differed by seizure type and the efficacy of SS in alerting responders. We screened 468 consecutive EMU admissions from January 2008 until April 2011 for definitive events to evaluate the first 50 events of complex partial seizures (CPS), generalized tonic-clonic seizures (GTC), and psychogenic non-epileptic seizures (PNES). Response to telemetry signal was slower than to push button (PB). When there was PB alarm, response time was slower in patients with PNES. A higher proportion of PNES were triggered by PB. A greater percentage of epileptic seizures were missed compared with PNES. Future studies investigating more effective techniques to capture every epileptic seizure are warranted as 24/7 monitoring by healthcare professionals is not feasible in many settings.

Successful ECT treatment for medically refractory nonconvulsive status epilepticus in pediatric patient.

Status epilepticus is a life threatening condition with a high mortality rate in spite of aggressive treatment. There is little consensus on third and fourth line approaches in refractory cases. While electroconvulsive therapy (ECT) has been employed successfully as a treatment for refractory epilepsy and status epilepticus (SE) after exhausting conventional therapy, its use for pediatric patients is limited. We describe a 7-year-old pediatric case in which ECT was used successfully to treat medically refractory nonconvulsive status epilepticus (NCSE) without complete withdrawal of antiepileptic drugs (AED).

Ultrasonographic reference values for assessing the normal median nerve in adults.

BACKGROUND AND PURPOSE: Several studies have evaluated the cross-sectional area of the median nerve at the wrist, but none have examined other sites along the median nerve. Nerve enlargement has been demonstrated in entrapment, hereditary and acquired neuropathies, as well as with intraneural masses, and cross-sectional area reference values at sites along the nerve will help in the evaluation of these conditions. In addition, muscle intrusion into the carpal tunnel has been implicated in carpal tunnel syndrome, but the normal amount of muscle intrusion has not been quantified. METHODS: Fifty asymptomatic volunteers (100 arms) were evaluated to determine the mean cross-sectional area of the median nerve at 6 sites and the mean amount of muscle intruding into the carpal tunnel. RESULTS: The cross-sectional area of the nerve was consistent along its course (7.5 to 9.8 mm(2)). The amount of muscle within the carpal tunnel varied greatly, with the mean area of flexor digitorum being 15.5 mm(2) and lumbricals 13.5 mm(2). CONCLUSIONS: These reference values are necessary for advancing the field of neuromuscular ultrasound, because they facilitate studies of the median nerve in conditions such as entrapment, hereditary neuropathy, acquired neuropathy, and intraneural masses.

Ultrasonographic findings of the normal ulnar nerve in adults.

OBJECTIVE: To provide a detailed description of the ultrasonographic findings along the entire length of the normative ulnar nerve. DESIGN: Volunteers were recruited to undergo ultrasonography of both upper extremities. Age, sex, height, weight, body mass index, arm length, and hand length were recorded, and cross-sectional measurements of the ulnar nerve were obtained at 7 predetermined sites. SETTING: The diagnostic neurology laboratory of a referral medical center. PARTICIPANTS: Thirty volunteers (60 arms) were recruited. Volunteers were screened by history and physical examination, and those with evidence of peripheral nervous system disease were excluded. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURE: The average cross-sectional area (CSA) of the ulnar nerve at 7 predetermined sites along the entire course of the nerve. RESULTS: The following average ulnar nerve CSAs were obtained: distal wrist crease, 5.9 mm2; arterial split, 6.3 mm2; 2 cm distal to tip of the medial epicondyle, 6.4 mm2; tip of the medial epicondyle, 6.5 mm2; 2cm proximal to tip of the medial epicondyle, 6.7 mm2; mid-humerus, 6.1 mm2; and axilla, 6.2 mm2. There was no statistical difference in nerve size when dominant and nondominant arms were compared, but women did have smaller nerves than men. Of all the variables measured, nerve size correlated most closely with weight, with a correlation coefficient of .59. CONCLUSIONS: The ulnar nerve was easily visualized and measured along its entire course, and the CSA of the nerve was consistent at multiple sites. The reference values obtained in this study will facilitate the analysis of abnormal nerve conditions, and the information on side-to-side variation and sex-specific differences should be particularly helpful.

Ultrasound in the diagnosis of ulnar neuropathy at the cubital tunnel.

PURPOSE: Ulnar neuropathy at the cubital tunnel (UCT) is diagnosed on the basis of history, physical examination, and nerve conduction studies (NCSs); however, the wide spectrum of findings often makes the diagnosis difficult. The purpose of this study was to document the ultrasonographic differences in ulnar nerve size between patients with UCT and control subjects, and to correlate those differences with clinical examination findings and NCS abnormalities, thereby testing the validity of ultrasound (US) as an additional adjunct diagnostic modality for UCT. METHODS: Fifteen elbows in 14 patients with symptoms, clinical examination, and NCS findings consistent with UCT had US of the ulnar nerve. Patients were excluded if they had a history of polyneuropathy, acute trauma involving the upper extremity, previous trauma in the region of the elbow (including previous surgery), or brachial plexus injury. The control group consisted of 60 elbows from 30 normal volunteers that also had US. Maximal cross-sectional areas (CSAs) were measured and compared for the 2 groups and a correlation analysis was performed between nerve size and NCS findings. RESULTS: The average CSA of the ulnar nerve was 0.065 cm(2) in the control group, whereas in the UCT group it was 0.19 cm(2), indicating a significant statistical difference in ulnar nerve size between the 2 groups. The Pearson correlation coefficient between motor nerve conduction velocity of the ulnar nerve and the CSA was 0.80. CONCLUSIONS: High-resolution US is a noninvasive, safe, and reliable modality for imaging the ulnar nerve at the elbow and it may provide a valuable adjunct to NCS in the diagnosis of UCT.