Does performing image registration and subtraction in ictal brain SPECT help localize neocortical seizures?

UNLABELLED: Ictal brain SPECT (IS) findings in neocortical epilepsy (patients without mesiotemporal sclerosis) can be subtle. This study is aimed at assessing how the seizure focus identification was improved by the inclusion of individual IS and interictal brain SPECT (ITS)-MRI image registration as well as performing IS - ITS image subtraction. METHODS: The study involved the posthoc analysis of 64 IS scans using 99mTc-ethyl cysteinate dimer that were obtained in 38 patients without mesiotemporal sclerosis but with or without other abnormalities on MRI. Radiotracer injection occurred during video-electroencephalographic (EEG) monitoring. Patients were injected 2-80 s (median time, 13 s) after clinical or EEG seizure onset. All patients had sufficient follow-up to correlate findings with the SPECT results. All patients had ITS and MRI, including a coronal volume sequence used for registration. Image registration (IS and ITS to MRI) was performed using automated software. After normalization, IS - ITS subtraction was performed. The IS, ITS, and subtraction studies were read by 2 experienced observers who were unaware of the clinical data and who assessed the presence and localization of an identifiable seizure focus before and after image registration and subtraction. Correlation was made with video-EEG (surface and invasive) and clinical and surgical follow-up. RESULTS: Probable or definite foci were identified in 38 (59%) studies in 33 (87%) patients. In 52% of the studies, the image registration aided localization, and in 58% the subtraction images contributed additional information. In 9%, the subtraction images confused the interpretation. In follow-up after surgery, intracranial EEG or video-EEG monitoring (or both) has confirmed close or reasonable localization in 28 (74%) patients. In 6 (16%) patients, SPECT indicated false seizure localization. CONCLUSION: Image registration and image subtraction improve the localization of neocortical seizure foci using IS, but close correlation with the original images is required. False localizations occur in a minority of patients.

Evaluation of an algorithm for treatment of status epilepticus in adult patients undergoing video/EEG monitoring.

Convulsive or generalized tonic clonic status epilepticus (SE) is a neurological emergency that can lead to transient or permanent brain damage or even death. An algorithm was designed to aid nursing and medical staff members in decision making about the type of SE and pharmacological intervention needed to stop prolonged or repetitive seizures. Fifteen registered nurses at a northern New England medical center's epilepsy unit participated in educational sessions on classification of seizures and status epilepticus prior to use of the algorithm. A pretest-posttest design with an investigator-developed tool was used to measure SE knowledge before and after educational intervention. There was a significant improvement in scores on the posttest of the classification of status epilepticus (Z = -2.93, p = .003). Twenty-nine medical records of patients who had experienced SE between February 1992 and December 1997 were reviewed. Nineteen patients experienced SE before the algorithm was implemented, and 10 patients experienced SE after the algorithm was implemented. A total of 16 patients experienced generalized convulsive SE with 12 episodes occurring before and 4 episodes after algorithm implementation. The mean time taken to stop the episode of SE after pharmacologic treatment began was compared in both groups using a t-test. The mean difference between the groups was 235 minutes (t = 2.57, p = .026). The findings of this project demonstrate that combining a treatment algorithm with education of staff members on its use has benefits in the practice setting of an inpatient comprehensive epilepsy program. Episodes of SE are more accurately classified and successful treatment of the episodes occurs earlier.

Use of primary care facilities by patients attending specialty clinics.

The health care patterns of 158 children attending a medical specialty clinic at least twice a year were studied. The families were interviewed about (1) use of a primary care source, (2) continued contact with the referring physician, and (3) perceived health needs. For almost one third of the children, no source of primary care was reported. This group contained a higher percentage of older children and children from the urban center than did the group as a whole. No differences were attributable to insurance coverage. Of patients referred by a primary care provider, 62% were still in contact with that provider, whereas only 20% referred from another hospital-based program were still in touch with that program. Of the children attending specialty clinics 60% had other perceived health needs. Thirty-eight percent of the families reported health problems that they had never discussed with any medical provider. This study indicates that a large proportion of children with frequent attendance at specialty clinics perceive the hospital as the source of all their care. Health planners and providers need to take this patient perception into account as they design and manage programs for chronically ill children.