18F-FDG PET and MR imaging associations across a spectrum of pediatric brain tumors: a report from the pediatric brain tumor consortium

The purpose of this study was to describe (18)F-FDG uptake across a spectrum of pediatric brain tumors and correlate (18)F-FDG PET with MR imaging variables, progression-free survival (PFS), and overall survival (OS).

METHODS

A retrospective analysis was conducted of children enrolled in phase I/II clinical trials through the Pediatric Brain Tumor Consortium from August 2000 to June 2010. PET variables were summarized within diagnostic categories using descriptive statistics. Associations of PET with MR imaging variables and PFS and OS by tumor types were evaluated.

RESULTS

Baseline (18)F-FDG PET was available in 203 children; 66 had newly diagnosed brain tumors, and 137 had recurrent/refractory brain tumors before enrolling in a Pediatric Brain Tumor Consortium trial. MR imaging was performed within 2 wk of PET and before therapy in all cases. The (18)F-FDG uptake pattern and MR imaging contrast enhancement (CE) varied by tumor type. On average, glioblastoma multiforme and medulloblastoma had uniform, intense uptake throughout the tumor, whereas brain stem gliomas (BSGs) had low uptake in less than 50% of the tumor and ependymoma had low uptake throughout the tumor. For newly diagnosed BSG, correlation of (18)F-FDG uptake with CE portended reduced OS (P = 0.032); in refractory/recurrent BSG, lack of correlation between (18)F-FDG uptake and CE suggested decreased PFS (P = 0.023). In newly diagnosed BSG for which more than 50% of the tumor had (18)F-FDG uptake, there was a suggestion of lower apparent diffusion coefficient (P = 0.061) and decreased PFS (P = 0.065).

CONCLUSION

(18)F-FDG PET and MR imaging showed a spectrum of patterns depending on tumor type. In newly diagnosed BSG, the correlation of (18)F-FDG uptake and CE suggested decreased OS, likely related to more aggressive disease. When more than 50% of the tumor had (18)F-FDG uptake, the apparent diffusion coefficient was lower, consistent with increased cellularity. In refractory/recurrent BSG, poor correlation between (18)F-FDG uptake and CE was associated with decreased PFS, which may reflect concurrent tissue breakdown at sites of treated disease and development of new sites of (18)F-FDG-avid malignancy.

Infantile postoperative encephalopathy: perioperative factors as a cause for concern

We report on 6 infants who underwent elective surgery and developed postoperative encephalopathy, which had features most consistent with intraoperative cerebral hypoperfusion. All infants were <48 weeks' postmenstrual age and underwent procedures lasting 120 to 185 minutes. Intraoperative records revealed that most of the measured systolic blood pressure (SBP) values were <60 mm Hg (the threshold for hypotension in awake infants according to the Pediatric Advanced Life Support guidelines) but that only 11% of the measured SBP values were <1 SD of the mean definition of hypotension (<45 mm Hg) as reported in a survey of members of the Society for Pediatric Anesthesia in 2009. Four infants also exhibited prolonged periods of mild hypocapnia (<35 mm Hg). One infant did not receive intraoperative dextrose. All infants developed new-onset seizures within 25 hours of administration of the anesthetic, with a predominant cerebral pathology of supratentorial watershed infarction in the border zone between the anterior, middle, and posterior cerebral arteries. Follow-up of these infants found that 1 died, 1 had profound developmental delays, 1 had minor motor delays, 2 were normal, and 1 was lost to follow-up. Although the precise cause of encephalopathy cannot be determined, it is important to consider the role that SBP hypotension (as well as hypoglycemia, hyperthermia, hyperoxia, and hypocapnia) plays during general anesthesia in young infants in the development of infantile postoperative encephalopathy. Our observations highlight the lack of evidence-based recommendations for the lower limits of adequate SBP and end-tidal carbon dioxide in anesthetized infants.

Recommendations for imaging tumor response in neurofibromatosis clinical trials

OBJECTIVE

Neurofibromatosis (NF)-related benign tumors such as plexiform neurofibromas (PN) and vestibular schwannomas (VS) can cause substantial morbidity. Clinical trials directed at these tumors have become available. Due to differences in disease manifestations and the natural history of NF-related tumors, response criteria used for solid cancers (1-dimensional/RECIST [Response Evaluation Criteria in Solid Tumors] and bidimensional/World Health Organization) have limited applicability. No standardized response criteria for benign NF tumors exist. The goal of the Tumor Measurement Working Group of the REiNS (Response Evaluation in Neurofibromatosis and Schwannomatosis) committee is to propose consensus guidelines for the evaluation of imaging response in clinical trials for NF tumors.

METHODS

Currently used imaging endpoints, designs of NF clinical trials, and knowledge of the natural history of NF-related tumors, in particular PN and VS, were reviewed. Consensus recommendations for response evaluation for future studies were developed based on this review and the expertise of group members.

RESULTS

MRI with volumetric analysis is recommended to sensitively and reproducibly evaluate changes in tumor size in clinical trials. Volumetric analysis requires adherence to specific imaging recommendations. A 20% volume change was chosen to indicate a decrease or increase in tumor size. Use of these criteria in future trials will enable meaningful comparison of results across studies.

CONCLUSIONS

The proposed imaging response evaluation guidelines, along with validated clinical outcome measures, will maximize the ability to identify potentially active agents for patients with NF and benign tumors.

Challenges with defining response to antitumor agents in pediatric neuro-oncology: a report from the response assessment in pediatric neuro-oncology (RAPNO) working group

Criteria for new drug approval include demonstration of efficacy. In neuro-oncology, this is determined radiographically utilizing tumor measurements on MRI scans. Limitations of this method have been identified where drug activity is not reflected in decreased tumor size. The RANO (Response Assessment in Neuro-Oncology) working group was established to address limitations in defining endpoints for clinical trials in adult neuro-oncology and to develop standardized response criteria. RAPNO was subsequently established to address unique issues in pediatric neuro-oncology. The aim of this paper is to delineate response criteria issues in pediatric clinical trials as a basis for subsequent recommendations.

Exploratory evaluation of MR permeability with 18F-FDG PET mapping in pediatric brain tumors: a report from the Pediatric Brain Tumor Consortium

The purpose of this study was to develop a method of registering (18)F-FDG PET with MR permeability images for investigating the correlation of (18)F-FDG uptake, permeability, and cerebral blood volume (CBV) in children with pediatric brain tumors and their relationship with outcome.

METHODS

Twenty-four children with brain tumors in a phase II study of bevacizumab and irinotecan underwent brain MR and (18)F-FDG PET within 2 wk. Tumor types included supratentorial high-grade astrocytoma (n = 7), low-grade glioma (n = 9), brain stem glioma (n = 4), medulloblastoma (n = 2), and ependymoma (n = 2). There were 33 cases (pretreatment only [n = 12], posttreatment only [n = 3], and both pretreatment [n = 9] and posttreatment [n = 9]). (18)F-FDG PET images were registered to MR images from the last time point of the T1 perfusion time series using mutual information. Three-dimensional regions of interest (ROIs) drawn on permeability images were automatically transferred to registered PET images. The quality of ROI registration was graded (1, excellent; 2, very good; 3, good; 4, fair; and 5, poor) by 3 independent experts. Spearman rank correlations were used to assess correlation of maximum tumor permeability (Kps(max)), maximum CBV (CBV(max)), and maximum (18)F-FDG uptake normalized to white matter (T/W(max)). Cox proportional hazards models were used to investigate associations of these parameters with progression-free survival (PFS).

RESULTS

The quality of ROI registration between PET and MR was good to excellent in 31 of 33 cases. There was no correlation of baseline Kps(max) with CBV(max) (Spearman rank correlation = 0.018 [P = 0.94]) or T/W(max) (Spearman rank correlation = 0.07 [P = 0.76]). Baseline CBV(max) was correlated with T/W(max) (Spearman rank correlation = 0.47 [P = 0.036]). Baseline Kps(max), CBV(max), and T/W(max) were not significantly associated with PFS (P = 0.42, hazard ratio [HR] = 0.97, 95% confidence interval [CI] = 0.90-1.045, and number of events [n(events)] = 15 for Kps(max); P = 0.41, HR = 0.989, 95% CI = 0.963-1.015, and n(events) = 14 for CBV(max); and P = 0.17, HR = 1.49, 95% CI = 0.856-2.378, and n(events) = 15 for T/W(max)).

CONCLUSION

(18)F-FDG PET and MR permeability images were successfully registered and compared across a spectrum of pediatric brain tumors. The lack of correlation between metabolism and permeability may be expected because these parameters characterize different molecular processes. The correlation of CBV and tumor metabolism may be related to an association with tumor grade. More patients are needed for a covariate analysis of these parameters and PFS by tumor histology.

Callosal dysgenesis in fetuses with ventriculomegaly: levels of agreement between imaging modalities and postnatal outcome

OBJECTIVE

To assess neurodevelopmental outcome of fetuses diagnosed with callosal abnormalities after referral for ventriculomegaly.

METHODS

This sub-analysis of a prospective study of 430 fetuses, which were referred for ventriculomegaly and underwent sonography and magnetic resonance imaging (MRI), included those fetuses with a diagnosis of corpus callosal abnormalities after recruitment into the main study. Between three and six radiologists independently reviewed ultrasound and MR images and recorded central nervous system (CNS) abnormalities, with final diagnoses being decided by consensus. Postnatal outcomes of fetuses with callosal abnormalities were compared between those with and those without other abnormalities.

RESULTS

Callosal abnormalities were detected in 13% (58/430) of the fetuses referred with ventriculomegaly. Callosal dysgenesis was isolated in 24% (14/58) of these cases, with the remainder complicated by CNS, karyotypic or other major abnormalities. Five fetuses diagnosed prenatally as having isolated callosal abnormalities had additional CNS findings on postnatal assessment. Preconference kappa for callosal abnormalities was 0.76 for ultrasound and 0.78 for MRI, indicating that these investigations had a similar level of operator dependence. Neurodevelopmental outcome was normal or showed only mild delay that resolved in 67% (8/12) children with isolated callosal abnormalities compared to 7% (2/27) in those with non-isolated callosal abnormalities (P = 0.003).

CONCLUSION

Callosal abnormalities are present in a significant proportion of fetuses with a diagnosis of ventriculomegaly. Isolated callosal abnormalities are associated with normal neurodevelopmental outcome in approximately two-thirds of fetuses.

Magnetic resonance volumetric assessments of brains in fetuses with ventriculomegaly correlated to outcomes

OBJECTIVES

The purpose of this study was to correlate 2-dimensional magnetic resonance (MR) measurements of lateral ventricular width and 3-dimensional measurements of lateral ventricular and supratentorial parenchymal volumes to postnatal outcomes in fetuses with ventriculomegaly.

METHODS

A total of 307 fetuses (mean gestational age, 26.0 weeks; range, 15.7-39.4 weeks) had MR volumetry after referral for ventriculomegaly. Fetuses were grouped into those with (n = 114) and without (n = 193) other central nervous system (CNS) anomalies. Pregnancy and postnatal neurodevelopmental outcomes up to 3 years of age were obtained. A subgroup analysis was performed excluding fetuses with other CNS anomalies. Logistic regression analysis was performed to assess which measurement was most predictive of outcomes.

RESULTS

There were 50 terminations, 2 stillbirths, and 255 live births. Seventy-five cases were lost to follow-up. Among 180 live-born neonates with follow-up, 140 had abnormal and 40 had normal outcomes. Atrial diameter (P < .0001), frontal horn diameter (P < .0001), and ventricular volume (P = .04) were predictive of live birth, with 92% specificity at 60% sensitivity. Among fetuses without other CNS anomalies, 180 of 193 pregnancies (93%) resulted in live deliveries, with atrial diameter (P < .0001), frontal horn diameter (P = .003), and ventricular volume (P = .008) associated with live birth and atrial diameter having the highest specificity (>99% at 60% sensitivity). Parenchymal volume was not associated with normal or abnormal outcomes (either live birth versus death or normal versus abnormal neurodevelopmental outcome). Among live-born neonates, no age-adjusted threshold for any of the measurements reliably distinguished between normal and abnormal neurodevelopmental outcomes.

CONCLUSIONS

Ventricular volume and diameter, but not parenchymal volume, correlate with live birth in fetuses with ventriculomegaly. However, once live born, neither 2- nor 3-dimensional measurements can distinguish a fetus that will have a normal outcome.

Frequency and cause of disagreements in imaging diagnosis in children with ventriculomegaly diagnosed prenatally

OBJECTIVES

To assess the frequency and cause of variability in diagnosis on cranial sonography and magnetic resonance imaging (MRI) in children referred following prenatal diagnosis of ventriculomegaly.

METHODS

Between 19 September 2003 and 16 March 2007, 119 infants with ultrasound and/or MRI studies performed within 13 months (median, 6 days) after birth, following prenatal referral for ventriculomegaly, were studied prospectively. There were 97 infants with ultrasound results and 53 with MRI, including 31 with both. Three sonologists and three pediatric neuroradiologists interpreted the postnatal ultrasound and MRI findings, blinded to prenatal diagnosis, and a final consensus diagnosis or group of diagnoses was obtained. Ventricular sizes as well as types of and reasons for any disagreement in diagnosis were recorded. Disagreements on a per patient basis were categorized as being major when they crossed diagnostic categories and had the potential to change patient counseling. Postnatal and prenatal diagnoses were compared.

RESULTS

There was prospective agreement on 42/97 (43%) ultrasound and on 9/53 (17%) MRI readings. Prospective consensus was more likely when the number of central nervous system (CNS) anomalies was lower (P < 0.001 and P = 0.002 for ultrasound and MRI, respectively). In 24/55 (44%) ultrasound and 11/44 (25%) MRI examinations with disagreement in diagnosis, there was disagreement concerning the presence of ventriculomegaly. In 22/97 (23%) ultrasound studies and 22/53 (42%) MRI studies the disagreements were potentially important. Reasons for discrepancies in the reporting of major findings included errors of observation as well as modality differences in depiction of abnormalities. In comparing prenatal with postnatal diagnoses, there were 11/97 (11%) ultrasound and 27/53 (51%) MRI examinations with newly detected major findings, the most common being migrational abnormalities, callosal dysgenesis/destruction and interval development of hemorrhage.

CONCLUSION

Variability in postnatal CNS diagnosis is common after a prenatal diagnosis of ventriculomegaly. This is due in part to a lack of standardization in the definition of postnatal ventriculomegaly.

Imaging of back pain in children

While back pain presents less frequently in children than in adults, it still poses a significant clinical challenge with respect to making a firm diagnosis and developing an effective treatment plan. When children have back pain and medical attention is sought, an underlying pathology is usually suspected. Pediatric patients are evaluated, first, with a complete clinical history and examination and, second, by an imaging work-up that is based on initial findings, including the child's age and size, signs and symptoms, and suspected etiology. This article describes 1) the epidemiology of back pain in children, 2) the imaging work-up used, and 3) the correlation of imaging findings with disease entities that may cause back pain in the pediatric patient. The list of diseases giving rise to back pain is not meant to be exhaustive but rather reflective of the most commonly identified pathologies and disorders among young children and adolescents, from athletic injuries to lethal cancers.

Frequency and cause of disagreements in diagnoses for fetuses referred for ventriculomegaly

PURPOSE

To prospectively assess the frequency and cause of disagreements in diagnoses at ultrasonography (US) and magnetic resonance (MR) imaging for fetuses referred for ventriculomegaly (VM).

MATERIALS AND METHODS

One hundred ninety-five women, aged 18-44 years, with 200 fetal referrals for VM, were recruited in a prospective IRB-approved, HIPAA-compliant study. Written informed consent was obtained. US scans were prospectively interpreted by three obstetric radiologists and MR examinations were read by one obstetric radiologist and three pediatric neuroradiologists. Final diagnosis was reached by consensus (198 US, 198 MR, and 196 US-MR comparisons). Gestational age, ventricular size, types of disagreements, and reasons for disagreements were recorded. Interreader agreement was assessed with kappa statistics. Ventricular diameter, gestational age, and confidence scores were analyzed by using mixed-model analysis of variance, accounting for correlation within reader and fetus.

RESULTS

There was prospective agreement on 118 (60%) of 198 US and 104 (53%) of 198 MR readings. Consensus was more likely when the final diagnosis was isolated VM (83 of 104, 80% at US; 82 of 109, 75% at MR) than when the final diagnosis included other anomalies as well (14 of 63, 22% at US; seven of 68, 10% at MR; P < .001). There was disagreement on 19 (10%) of 196 and 31 (16%) of 196 fetuses about the presence of VM at US and MR, respectively, and on 29 (15%) of 198 and 39 (20%) of 198 fetuses regarding the presence of major findings at US and MR, respectively. Reasons for discrepancies in reporting major findings included errors of observation, lack of real-time US scanning, lack of neuroradiology experience, as well as modality differences in helping depict abnormalities.

CONCLUSION

Of radiologists who read high-risk obstetric US and fetal MR images for VM, there is considerable variability in central nervous system diagnosis.

Phase I trial of single-dose temozolomide and continuous administration of o6-benzylguanine in children with brain tumors: a pediatric brain tumor consortium report

PURPOSE

To estimate the maximum tolerated dose (MTD) and dose-limiting toxicity (DLT) of escalating doses of temozolomide combined with O(6)-benzylguanine in patients < or =21 years with recurrent brain tumors.

EXPERIMENTAL DESIGN

Treatment strata consisted of patients who had previously received no or local radiotherapy (Str1) and patients who had undergone craniospinal radiotherapy or myeloablative chemotherapy (Str2). One-hour i.v. administration of O(6)-benzylguanine at 120 mg/m(2) was followed by 48-h continuous infusion at 30 mg/m(2)/day. Single-dose temozolomide at five dosage levels (267, 355, 472, 628, and 835 mg/m(2)) was given at least 6 h after completion of O(6)-benzylguanine bolus. Treatment was repeated after recovery from toxicities at least 4 weeks apart for a maximum of 12 courses. Dose escalation followed the modified continual reassessment method. Pharmacokinetic analyses of temozolomide and 5-triazeno imidazole carboxamide (MTIC) were done in 28 patients.

RESULTS

A total of 44 and 26 eligible patients were enrolled on Str1 and Str2, respectively. Median age at study entry in each stratum was 8.6 and 11.3 years, respectively. Predominant diagnoses were high-grade/brainstem glioma in Str1 and medulloblastoma in Str2. Whereas the estimated MTDs of temozolomide for Str1 and Str2 were 562 and 407 mg/m(2), respectively, the doses recommended for phase II investigations are 472 and 355 mg/m(2), respectively. DLTs were predominantly neutropenia and thrombocytopenia. Three patients with gliomas experienced centrally confirmed partial responses to therapy. Four patients completed all planned therapy. Temozolomide and MTIC exposures were statistically associated with temozolomide dosage.

CONCLUSIONS

The current schedule of temozolomide and O(6)-benzylguanine is safe and showed modest activity against recurrent brain tumors in children.

Age associated increase in the prevalence of chromosome 22q loss of heterozygosity in histological subsets of benign meningioma

Chromosome 22q loss of heterozygosity (LOH) is the most common allelic loss in benign meningioma and is thought to be the earliest initiating event in meningioma formation. We used published data and logistic regression to evaluate the association of 22q LOH with age at diagnosis in 318 transitional, fibroblastic, and meningothelial meningiomas. After adjustment for anatomical location, the odds ratio of 22q LOH per year of age was >1 in each histological type of meningioma, and was significantly >1 in transitional and fibroblastic meningioma. This finding is compatible with involvement of the neurofibromatosis 2 tumour suppressor gene, NF2, on chromosome 22q in the high incidence of benign meningioma in the elderly.

Perfusion MRI of U87 brain tumors in a mouse model

Continuous arterial spin labeling (CASL) was used to obtain an index of cerebral blood flow (ICBF) in the normal mouse brain and in an orthotopic mouse model of human U87 high-grade glioma at 8.5 T. Under the assumption of a constant tissue:blood partition coefficient for water in different tissues, the mean ICBF (n = 14) was found to be 50 +/- 9 mL/100g/min for tumor core and 209 +/- 11 mL/100g/min for normal tissue. The apparent T(1) (T(1app)) was 2.01 +/- 0.06 sec for tumor core and 1.66 +/- 0.03 sec for normal tissue. The ICBF and the T(1app) values were significantly different (P < 0.001) between these two regions. The detailed changes of ICBF and T(1app) in the transition from the tumor core through the tumor periphery to surrounding tissue were studied. Immunohistochemistry indicated that tumor vascularity was not uniform, with microvessel density highest in normal brain and the tissue surrounding the tumor and lowest in the tumor core. The large difference in ICBF between the tumor core and normal tissue suggests that this index might be useful for the assessment of the efficacy of antiangiogenic therapy.

MRI and 1H MRS findings in Smith-Lemli-Opitz syndrome

Smith-Lemli-Opitz syndrome (SLOS) is an autosomal recessive disorder characterized by a defect in cholesterol biosynthesis, associated with mental retardation and multisystem structural abnormalities. This study investigated the prevalence of congenital CNS abnormalities by MRI in a large series of patients with SLOS and the correlation of the clinical and biochemical findings with the results of MRI and 1H MRS. Eighteen patients were studied; all underwent MRI of the brain, and 16 had 1H MRS of the cerebral white matter. The ratios choline:NAA, lipid:NAA, and lipid:choline metabolite were found to be correlated with the clinical degree of disease severity, serum total sterol ratios (cholesterol/cholesterol + 7-dehydrocholesterol + 8-dehydrocholesterol) and in two cases with the effect of cholesterol therapy. Abnormal CNS findings were noted in five patients, including callosal abnormalities (n = 4), Dandy-Walker variant (n = 1), and arachnoid cyst (n = 1). Holoprosencephaly was noted in one patient with a prevalence of 6%. Choline:NAA was elevated in seven patients. There was a statistically significant positive correlation between the lipid:choline ratio and the serum cholesterol precursor, 8-dehydrocholesterol. In two patients 1H MRS demonstrated abnormally elevated lipids prior to cholesterol therapy, which improved on therapy. The use of MRI and 1H MRS is an effective way to demonstrate brain structural abnormalities in patients with SLOS and may prove to be an effective method for the assessment of the effects of cholesterol replacement therapy in the brain.

Magnetic resonance imaging of pediatric brain tumors: state of the art

Over the past 25 years, magnetic resonance imaging (MRI) has developed into the primary imaging tool for evaluation of the central nervous system. MRI is the essential imaging study in the twenty-first century for the evaluation of the child with a brain tumor for initial preoperative diagnosis, treatment planning and image-guided therapies. This article provides an overview of the locations and MRI features of common pediatric tumors of childhood.

Magnetic resonance spectroscopy and magnetic resonance imaging findings in Krabbe's disease

Two twins with late infantile globoid cell leukodystrophy of Krabbe's disease were studied with conventional magnetic resonance imaging (MRI) and proton magnetic resonance spectroscopy. Brain MRI demonstrated brain atrophy with extensive bilateral symmetric abnormal T2 signal in the posterior periventricular white matter, parietal lobes, corona radiata, centrum semiovale, and splenium of the corpus callosum. Magnetic resonance imaging-guided proton magnetic resonance spectroscopy revealed prominent peaks from choline-containing compounds, total creatine, and inositols. The N-acetylaspartate peak was markedly reduced, and the choline-to-N-acetylaspartate ratio was abnormally high; in one of the twins, lactic acid was also detected. The constellation of magnetic resonance spectroscopy findings is indicative of extensive demyelination, gliosis, and loss of axons in the involved white matter; the latter two events occur in the later stages of globoid cell leukodystrophy. In conjunction with brain MRI, these magnetic resonance spectroscopy findings may alert clinicians to the possibility of leukodystrophy in children with progressive encephalopathy.

Proton magnetic spectroscopic imaging of the child's brain: the response of tumors to treatment

Our aim was to determine and/or predict response to treatment of brain tumors in children using proton magnetic resonance spectro-scopic imaging (MRSI). We studied 24 patients aged 10 months to 24 years, using MRI and point-resolved spectroscopy (PRESS; TR 2000 TE 65 ms) with volume preselection and phase-encoding in two dimensions on a 1.5 T imager. Multiple logistic regression was used to establish independent predictors of active tumor growth. Biologically vital cell metabolites, such as N-acetyl aspartate and choline-containing compounds (Cho), were significantly different between tumor and control tissues (P < 0.001). The eight brain tumors which responded to radiation or chemotherapy, exhibited lower Cho (P = 0.05), higher total creatine (tCr) (P = 0.02) and lower lactate and lipid (L) (P = 0.04) than 16 tumors which were not treated (except by surgery) or did not respond to treatment. The only significant independent predictor of active tumor growth was tCr (P < 0.01). We suggest that tCr is useful in assessing response of brain tumors to treatment.

Periventricular nodular heterotopia in patients with filamin-1 gene mutations: neuroimaging findings

BACKGROUND

The filamin-1 (FLN-1) gene is responsible for periventricular nodular heterotopia (PNH), which is an X-linked dominant neuronal migration disorder.

OBJECTIVE

To review the clinical and imaging findings in a series of patients with documented filamin-1 mutations.

MATERIALS AND METHODS

A retrospective review of the medical records and MR studies of a series of patients with PNH and confirmed FLN-1 mutations was done. There were 16 female patients (age range: .67-71 years; mean = 28.6) with filamin-1 gene mutations.

RESULTS

In six of the patients the same mutation was inherited in four generations in one pedigree. In a second pedigree, a distinct mutation was found in two patients in two generations. In a third pedigree, a third mutation was found in four patients in two generations. The remaining four patients had sporadic de novo mutations that were not present in the parents. Ten patients had seizures, and all patients had normal intelligence. In all 16 patients MR demonstrated bilateral near-continuous PNH. There were no consistent radiographic or clinical differences between patients carrying different mutations.

CONCLUSION

Patients with confirmed FLN-1 gene mutations are usually female and have a distinctive MR pattern of PNH. Other female patients with this same MR pattern probably harbor FLN-1 mutations and risk transmission to their progeny. This information is important for genetic counseling.

Neurological dysfunction associated with postoperative cerebellar mutism

BACKGROUND AND OBJECTIVES

The postoperative cerebellar mutism syndrome (CMS) is an unique acute postoperative complication characterized by transient decrease in speech output (often mutism), apathy, irritability as well as global cerebellar dysfunction. As much as 25% of patients undergoing a resection of a cerebellar or IV ventricular tumor may develop such a syndrome. In this retrospective study we characterize the clinical features of the CMS and explore potential etiologic mechanisms.

METHODS

We conducted a retrospective analysis of medical records and imaging tests of 8 consecutive patients with the CMS identified through the database of the Children's Hospital and Dana-Farber Cancer Institute, Boston, and compared with a control group of 8 unaffected children undergoing a comparable tumor resection.

RESULTS

In contrast to the control group, children in the affected group had marked decrease in speech output and comprehension, apathy and lack of initiative, inattention, persistent eye closure, flaccid hemiparesis and a severe global cerebellar dysfunction. Swallowing difficulties and bowel and bladder dysfunction were also observed. The median duration of the syndrome as judged by the persistence of the communication abnormalities was 4 weeks. The recovery was near complete with exception for a persistent global cerebellar dysfunction. A comparison of CT and MRI scans of children in both groups failed to identify distinguishing features.

CONCLUSION

A surgical lesion of the midline cerebellum can cause a complex neurological dysfunction such as the CMS. Thus, we postulate that the cerebellum and its connections function as a 'modulatory system' in control of both motor and non-motor functions, including attention and language.

Occult lumbosacral dysraphism in children and young adults: diagnostic performance of fast screening and conventional MR imaging

PURPOSE

To compare fast screening and conventional magnetic resonance (MR) imaging for the detection of occult dysraphic myelodysplasias in children and young adults.

MATERIALS AND METHODS

A retrospective case-control study included 101 patients (mean age, 4.9 years; range, 1 day to 26 years) suspected of having occult lumbosacral dysraphism. Sixty case patients had myelodysplastic lesions (19 filar lipoma, 14 syringomyelia, 10 intradural lipoma, eight dermal sinus, five diastematomyelia, five lipomyelomeningocele, two caudal regression syndrome); 41 control patients had no dysraphic lesions; 17 patients had associated renal anomalies. Two neuroradiologists reviewed MR images from conventional and fast screening protocols. Diagnostic performance parameters included sensitivity, specificity, and area under the receiver operating characteristic curve (Az value).

RESULTS

The sensitivity of conventional and fast screening MR studies was 97.1% and 98.5%, respectively, the specificity was 90.9% and 84.8%, respectively. The Az value was 0.973 for the fast screening and 0.976 for the conventional MR studies (P = .83). Interobserver agreement was very good for fast screening images (kappa = 0.68) and excellent for conventional images (kappa = 0.75). For renal anomalies, the Az value was 0.786 and 0.853 for fast screening and conventional MR imaging, respectively (P = .28).

CONCLUSION

Conventional three-plane lumbosacral MR imaging in children and young adults suspected of having occult dysraphism provides better diagnostic information than does fast screening two-plane MR imaging because of its higher specificity and interobserver agreement.

Structural anomalies revealed by neuroimaging studies in the brains of patients with neurofibromatosis type 1 and large deletions

PURPOSE

The basis for cognitive problems in patients with neurofibromatosis type 1 (NF1) is unknown. A subset of NF1 patients with deletion of the entire NF1 gene has severe learning problems or mental retardation. We have reviewed neuroimaging studies (CT and MRI) in five such patients to determine whether structural anomalies in the brain are present and might explain the impaired cognitive function.

METHODS

Five patients with NF1 and deletion of the entire gene were identified by FISH studies. A retrospective review was conducted of CT and MRI images, as well as of data from developmental assessments.

RESULTS

All five patients had severe developmental impairment. None had been exposed to chemotherapy or radiation therapy. All had multiple regions of bright T2 signal intensity. Structural anomalies were seen in three of the five patients and included callosal dysgenesis in one, septum cavum vergae and pellucidum in two, mega cisterna magna in one, and Chiari I malformation with severe hydrocephalus in one patient.

CONCLUSION

Individuals with NF1 and large gene deletions have an increased frequency of structural anomalies of the brain not usually seen in NF1 patients. This suggests that the mental retardation in these individuals is due, at least in part, to abnormal brain development rather than a defect in brain function due to haplosufficiency of the NF1 gene product.

Imaging of neuroendocrine disorders of childhood

This article focuses on the neuroendocrine disorders of childhood. The commonly associated neuroradiologic abnormalities of the hypothalamic-pituitary axis are covered in detail.

Neuroimaging of scoliosis in childhood

A curvature abnormality may be the initial or major presenting feature in a child with disease of the spinal column or spinal neuraxis. A simplified classification of common spinal curvature abnormalities of childhood include idiopathic, congenital/dysraphic, skeletal dysplasia, neurofibromatosis, and painful. The great majority of childhood scoliosis falls into the idiopathic category. Atypical clinical or radiographic features in a presumed idiopathic scoliosis may indicate an otherwise occult tumor or hydrosyringomyelia, or may be a consequence of increasing curvature with disk protrusion, nerve impingement, or cord attenuation. Neuroimaging beyond plain films is commonly necessary for atypical idiopathic scoliosis and for the other categories of scoliosis listed.