Pediatric applications of functional magnetic resonance imaging.

Pediatric functional MRI has been used for the last 2 decades but is now gaining wide acceptance in the preoperative workup of children with brain tumors and medically refractory epilepsy. This review covers pediatrics-specific difficulties such as sedation and task paradigm selection according to the child's age and cognitive level. We also illustrate the increasing uses of functional MRI in the depiction of cognitive function, neuropsychiatric disorders and response to pharmacological agents. Finally, we review the uses of resting-state fMRI in the evaluation of children and in the detection of epileptogenic regions.

Hemangiomas revisited: the useful, the unusual and the new. Part 1: overview and clinical and imaging characteristics.

Hemangiomas are common vascular tumors occurring in children. Though most of the lesions present in infants and young children with a typical appearance, it is important to understand that they all do not behave in the same way. Rather, they are a group of vascular lesions with different clinico-pathological subtypes, with their clinical behavior varying with the stage of the tumor as well. As such, they can and do have a varied clinical, imaging and pathological appearance according to the location of the tumor and also the stage at which the patient is seen. In this pictorial essay, the classification, pathogenesis, clinical appearance, natural history and imaging characteristics of hemangiomas are reviewed and illustrated.

Hemangiomas revisited: the useful, the unusual and the new. Part 2: endangering hemangiomas and treatment.

Hemangiomas, although benign tumors, can when located in particular regions threaten vital structures or in certain clinical circumstances be associated with other abnormalities, carrying significant morbidity and mortality. We review these endangering hemangiomas. We also discuss briefly the treatment with emphasis on the recent use of propranolol.

Vesicoureteral reflux imaging in children: comparative cost analysis.

RATIONALE AND OBJECTIVES: The purpose of this study was to compare the costs of voiding cystourethrography (VCUG) versus radionuclide cystography (RNC) for evaluation of vesicoureteral reflux in children. MATERIALS AND METHODS: The variable direct costs of performing 25 VCUG and 25 RNC examinations in age- and general health-matched patients suspected of having vesicoureteral reflux was determined by using time and motion analyses. All personnel directly involved in the cases were tracked, and the involvement times were recorded to the nearest minute. All material items used during the procedures were recorded. The cost of labor was determined from personnel reimbursement data, and the cost of materials, from vendor pricing. The fixed direct costs were assessed from hospital accounting records. Mean, standard deviation, and 95% confidence interval (CI) were determined for all direct (fixed and variable) costs. The total costs were determined for each procedure and compared by using the Student t test. RESULTS: There was a significant difference (P < .0001) between the mean total direct cost of VCUG ($112.17 +/- 10.33) and that of RNC ($64.58 +/- 1.91). VCUG examination for vesicoureteral reflux in children cost 1.74 times more than RNC examination (95% CI: 1.28, 2.36). CONCLUSION: When the technique is clinically appropriate, institutions may obtain substantial cost savings by using RNC in place of VCUG for examining children suspected of having vesicoureteral reflux.

Evidence-based medicine: neuroimaging of seizures.

Evidence-based medicine is useful in epilepsy and neuroimaging (Figs. 1 and 2). An understanding of the pretest probability suggests that focal neurologic deficits are important in predicting the outcome of neuroimaging examinations. In cases of nonacute symptomatic seizures, confusion and postictal deficits should prompt MR evaluation. In remote symptomatic seizures, MR imaging should be performed in a child with unexplained cognitive or motor delays or a child less than 1 year of age. Patients with partial seizures, abnormal EEG, or generalized epilepsy also should be imaged. Acute seizures should be imaged with CT to exclude hemorrhage and because of the availability and speed of the modality. Ictal SPECT is the best neuroimaging examination to localize seizure activity. MR imaging can offer prediction of surgical outcome and may hold promise in the future for dimensional localization of seizure focus. Evidence-based medicine can only work if there is physician communication. The pretest probability is helpful only when an accurate history is provided to the consulting physician. This field will flourish if physicians can develop accurate methods of collating information and reporting it in a timely fashion in the literature.

The "hinge-twist" technique for anomalous origin of the left coronary artery.

A murmur was heard in an asymptomatic boy (age 4), and transthoracic echocardiography revealed anomalous origin of the left main coronary artery (LMCA) from the right sinus of Valsalva (age 6). Confirmed by catheterization and computed tomographic angiography (age 10), the LMCA followed a short interarterial course between the aorta and main pulmonary artery before supplying the anterior descending and circumflex coronary arteries. An intramural segment was not clearly seen. Results of stress testing were normal. Because sudden death was a concern, the patient underwent surgery at age 11. The "hinge-twist" technique was utilized in the absence of an intramural component or ostial stenosis in an effort to avoid the long-term complications of coronary reimplantation, ostial patching, or bypass grafting.

Diagnostic performance of MRI and MR myelography in infants with a brachial plexus birth injury.

BACKGROUND: Detailed evaluation of a brachial plexus birth injury is important for treatment planning. OBJECTIVE: To determine the diagnostic performance of MRI and MR myelography in infants with a brachial plexus birth injury. MATERIALS AND METHODS: Included in the study were 31 children with perinatal brachial plexus injury who underwent surgical intervention. All patients had cervical and brachial plexus MRI. The standard of reference was the combination of intraoperative (1) surgical evaluation and (2) electrophysiological studies (motor evoked potentials, MEP, and somatosensory evoked potentials, SSEP), and (3) the evaluation of histopathological neuronal loss. MRI findings of cord lesion, pseudomeningocele, and post-traumatic neuroma were correlated with the standard of reference. Diagnostic performance characteristics including sensitivity and specificity were determined. RESULTS: From June 2001 to March 2004, 31 children (mean age 7.3 months, standard deviation 1.6 months, range 4.8-12.1 months; 19 male, 12 female) with a brachial plexus birth injury who underwent surgical intervention were enrolled. Sensitivity and specificity of an MRI finding of post-traumatic neuroma were 97% (30/31) and 100% (31/31), respectively, using the contralateral normal brachial plexus as the control. However, MRI could not determine the exact anatomic area (i.e. trunk or division) of the post-traumatic brachial plexus neuroma injury. Sensitivity and specificity for an MRI finding of pseudomeningocele in determining exiting nerve injury were 50% and 100%, respectively, using MEP, and 44% and 80%, respectively, using SSEP as the standard of reference. MRI in infants could not image well the exiting nerve roots to determine consistently the presence or absence of definite avulsion. CONCLUSION: In children younger than 18 months with brachial plexus injury, the MRI finding of pseudomeningocele has a low sensitivity and a high specificity for nerve root avulsion. MRI and MR myelography cannot image well the exiting nerve roots to determine consistently the presence or absence of avulsion of nerve roots. The MRI finding of post-traumatic neuroma has a high sensitivity and specificity in determining the side of the brachial plexus injury but cannot reveal the exact anatomic area (i.e. trunk or division) involved. The information obtained is, however, useful to the surgeon during intraoperative evaluation of spinal nerve integrity for reconstruction.

Seizure disorders: functional MR imaging for diagnostic evaluation and surgical treatment--prospective study.

PURPOSE: To prospectively evaluate effect of functional magnetic resonance (MR) imaging on diagnostic work-up and treatment planning in patients with seizure disorders who are candidates for surgical treatment. MATERIALS AND METHODS: Institutional review board approval was obtained; informed consent was obtained either from the patient or the parent or guardian in all patients. This study was conducted with Health Insurance Portability and Accountability Act compliance. Sixty consecutively enrolled patients (33 males, 27 females; mean age, 15.8 years +/- 8.7 [standard deviation]; range, 6.8-44.2 years) were prospectively examined. Forty-five (75%) patients were right handed, nine (15%) were left handed, and six (10%) had indeterminate hand dominance. Prospective questionnaires were used to evaluate diagnostic work-up, counseling, and treatment plans of the seizure team before and after functional MR imaging. Confidence level scales were used to determine effect of functional MR imaging on diagnostic and therapeutic thinking. Paired t test and 95% confidence interval analyses were performed. RESULTS: In 53 patients, language mapping was performed; in 33, motor mapping; and in seven, visual mapping. The study revealed change in anatomic location or lateralization of language-receptive (Wernicke) (28% of patients) and language-expressive (Broca) (21% of patients) areas. Statistically significant increases were found in confidence levels after functional MR imaging in regard to motor and visual cortical function evaluation. In 35 (58%) of 60 patients, the seizure team thought that functional MR imaging results altered patient and family counseling. In 38 (63%) of 60 patients, functional MR imaging results helped to avoid further studies, including Wada test. In 31 (52%) and 25 (42%) of 60 patients, intraoperative mapping and surgical plans, respectively, were altered because of functional MR imaging results. In five (8%) patients, two-stage surgery with extra-operative direct electrical stimulation mapping was averted, and resection was accomplished in one stage. In four (7%) patients, extent of surgical resection was altered because eloquent areas were identified close to seizure focus. CONCLUSION: Functional MR imaging results influenced diagnostic and therapeutic decision making of the seizure team; results indicated language dominance changed, confidence level in identification of critical brain function areas increased, patient and family counseling were altered, and intraoperative mapping and surgical approach were altered.

Establishing a health outcomes and economics center in radiology: strategies and resources required.

PURPOSE: To describe the resources and strategies required to establish a health outcomes and economics center in radiology. METHODS: Human and nonhuman resources required to perform sound outcomes and economics studies in radiology are reviewed. RESULTS: Human resources needed include skilled medical and nonmedical staff. Nonhuman resources required are: (1). communication and information network; (2). education tools and training programs; (3). budgetary strategies; and (4). sources of income. Effective utilization of these resources allows the performance of robust operational and clinical research projects in decision analysis, cost-effectiveness, diagnostic performance (sensitivity, specificity, and ROC curves), and clinical analytical and experimental studies. CONCLUSION: As new radiologic technology and techniques are introduced in medicine, society is increasingly demanding sound clinical studies that will determine the impact of radiologic studies on patient outcome. Health-care funding is scarce, and therefore third-party payers and hospitals are demanding more efficiency and productivity from radiologic service providers. To meet these challenges, radiology departments could establish health outcomes and economics centers to study the clinical effectiveness of imaging and its impact on patient outcome.

Speech delay in children: a functional MR imaging study.

PURPOSE: To determine if children with speech delay who have been sedated have patterns of activation to passive language paradigms that are different than those of children with normal speech. MATERIALS AND METHODS: Seventeen children with speech delay (age range, 2-7 years; mean, 4.0 years) and 35 age-matched children with normal speech (age range, 2-8 years; mean, 4.2 years) were evaluated. The subjects in the control group were selected from patients referred for conventional magnetic resonance (MR) imaging. All children had absence of auditory impairment or mental retardation, and MR findings indicated that brain structure was normal. Sedation was achieved with pentobarbital (3-5 mg/kg) or chloral hydrate (75 mg/kg). Functional MR imaging was performed with a single-shot echo-planar blood oxygen-level-dependent technique and a passive block paradigm, in which the child listened to his or her mother's prerecorded voice. Statistical postprocessing of functional MR images was performed with the t test and cluster detection methods. Comparison between groups was performed depending on the type of data with a nonparametrical Mann-Whitney test, parametrical t test, or Fisher exact test. RESULTS: Five (83%) of the six children older than 3 years with speech delay had lateralized activation of functional MR imaging signal in the right hemisphere. Ten (71%) of 14 age-matched patients with normal speech had activation in the left hemisphere when exposed to the same passive listening tasks. When these groups were compared, this difference was statistically significant. (P =.036). No statistically significant lateralization was seen across all age groups in children with activation. CONCLUSION: Children older than 3 years with speech delay have activation in the right hemisphere more frequently than children older than 3 years with normal speech, who often have the expected finding of activation in the left hemisphere.

Dissecting nonverbal auditory cortex asymmetry: an fMRI study.

The purpose of this study was to find a robust nonverbal paradigm to obtain reliable, reproducible auditory activation and characterize the nonverbal activation of the auditory cortex in regard to the Brodmann regions. The extent of localization and lateralization of activation was investigated utilizing functional magnetic resonance (fMR). Two tasks were used: monotonous repetitive stimuli of "double octaves" (DO) consisting of alternating four A with four C piano notes and a variated string of "sequential notes" (SN), which was a fast nonrepetitive sequence of piano notes. Eleven volunteers were investigated. The activation periods had a duration of 30 s, and presented every 30 s. All subjects demonstrated fMRI signal activity in the superior temporal gyrus (STG) involving the primary and secondary auditory cortex except one subject who showed no activation with the DO stimulus. SN elicited more activation than DO (p =<.03). The bulk activation for SN and DO was slightly greater in the right hemisphere, although the primary auditory area (Brodmann's 41) was better activated on the left p =<.001. Brodmann's area 22 was most frequently right-side dominant (p =.015, p =.017 for DO and SN, respectively). These findings appear to have implications in the examination of preverbal subjects.

Acalculia: an fMRI study with implications with respect to brain plasticity.

We report the case of a 44-year-old right-handed man with severe acalculia and 4 normal age-matched controls. The acalculia patient had magnetic resonance findings of a wedge shaped defect in the left posterior temporal-parietal cortex, involving the angular gyrus, and a lacunar infarct of the right thalamus. Functional magnetic resonance exams were performed utilizing four tasks consisting of serial subtracting by sevens, basic calculation, complex calculation, and abstract calculation. Both patient and controls showed specific task-related activation with some differences that may indicate brain plasticity, even though no significant recovery in calculations abilities was observed in the patient.

Functional MR imaging versus Wada test for evaluation of language lateralization: cost analysis.

PURPOSE: To compare the total direct costs (fixed and variable costs) of functional magnetic resonance (MR) imaging and of the Wada test for evaluation of language lateralization. MATERIALS AND METHODS: The direct fixed and variable costs of functional MR imaging (performed in 21 patients with mean age +/- SD of 15.5 years +/- 8.9) and of the Wada test (performed in 18 patients aged 19.2 years +/- 5.4) were determined prospectively with time and motion analyses. The labor of all personnel involved in evaluations of language lateralization was tracked, and involvement times were recorded to the nearest minute. All material items used in the studies were recorded. Costs of labor and of materials were determined from personnel reimbursement data and from vendor pricing, respectively. Direct fixed costs were determined from hospital accounting department records. Means (+/- SDs) were calculated for all direct fixed and variable costs. Total direct costs were determined for each procedure and compared by using the Student t test. RESULTS: The total direct costs of the Wada test (US dollars 1130.01 +/- US dollars 138.40) and of functional MR imaging (US dollars 301.82 +/- US dollars 10.65) were significantly different (P <.001). The cost of the Wada test was 3.7 times higher than that of functional MR imaging. CONCLUSION: Substantial savings are achievable with the use of functional MR imaging instead of the Wada test to evaluate language lateralization.