Pre- and post-stroke MRI and neuropsychological studies in sickle cell disease: a case study

The case of a patient with sickle cell disease is presented in which neuropsychological and magnetic resonance imaging studies were completed prior to and after a right hemispheric stroke. The contribution of a new MR perfusion technique in understanding the neurological complications in this patient is discussed. This case illustrates the complex pathophysiology of neuropsychological deficits in SCD and underscores the need to develop models that better reflect this complexity.

Bone marrow transplantation in a young child with sickle cell anemia

Bone marrow transplantation (BMT) is the only curative therapy available for hemoglobinopathies. BMT was performed on a young child with sickle cell anemia (SCA) after approximately 9 months of transfusion therapy following her initial stroke. The patient received a matched sibling donor (sickle trait) BMT. The conditioning regimen consisted of busulfan 4 mg/kg/day x 4, cyclophosphamide 50 mg/kg/day x 4. Graft vs. host disease prophylaxis was daily cyclosporine for 6 months. There were no significant complications during BMT. Engraftment occurred on day +17 and the patient was transfusion independent since day +45. Pre-BMT cerebral arteriography showed multiple stenotic cerebral vessels and a moya-moya pattern. Perfusion MRI demonstrated reduced capillary perfusion. Approximately 170 days after BMT the patient experienced episodes of transient left-sided weakness and speech problems. Neuroimaging revealed progression of large vessel pathology by angiography despite significant improvement in cortical perfusion (MR perfusion scan). Molecular analysis by PCR and DNA fingerprinting confirmed absence of mixed mosaicism. Rheologic evaluation showed normal corrected bulk viscosity. It is possible that progression of large vessel pathology and return of clinical symptoms in the face of normal rheologic parameters may be due to worsening of the already damaged cerebral vessels by the BMT conditioning regimen. Further evaluations of patients with SCA undergoing BMT after a stroke are needed to answer this question.

Dermoids of the eustachian tube: CT and MR findings with histologic correlation

Two patients with congenital dermoids of the eustachian tube presented with recurrent otitis media and chronic otorrhea resistant to antimicrobial therapy. CT demonstrated fat density, homogeneous lesions, filling and expanding the eustachian tube. On MR, signal from the lesions was consistent with fat, and the relationship with the internal carotid artery was better delineated than by CT. Microscopically, the masses consisted of a conglomeration of ectodermal and mesodermal elements.

MR findings in kernicterus

We describe the MR appearance of kernicterus (bilirubin encephalopathy). T2-weighted images show high signal bilaterally in the globus pallidus, a known area of cerebral deposition of bilirubin.

Review of the embryologic development of the pituitary gland and report of a case of hypophyseal duplication detected by MRI

We describe the clinical manifestations, associated abnormalities, MRI appearances and pathologic significance of a case of hypophyseal duplication. A 16-year-old girl presented with delayed sexual development and history of midline craniofacial anomalies. MRI revealed paired infundibula extending inferiorly to two small pituitary glands, a midline hypothalamic mass, and a midline cleft in the basisphenoid. Twelve cases of pituitary duplication have previously been described. The suggested pathogenesis is duplication of the prechordal plate and anterior end of the notochord during early embryologic development.

Familial erythrophagocytic lymphohistiocytosis: neuroradiologic evaluation with pathologic correlation

PURPOSE

To report neuroradiologic findings in eight patients with familial erythrophagocytic lymphohistiocytosis (FEL), a rare, fatal autosomal recessive disease of infancy.

MATERIALS AND METHODS

All patients underwent neuroradiologic magnetic resonance (MR) imaging and computed tomography before and after treatment. MR imaging-guided proton MR spectroscopy was performed in four.

RESULTS

Seizures, focal neurologic deficits, and gait abnormalities were the most common neurologic manifestations. Brain involvement on MR images was progressive and consisted of parenchymal atrophy, diffuse abnormal signal intensity in the white matter on T2-weighted images, focal hyperintense lesions in both the white and gray matter, delayed myelination, and parenchymal calcifications. MR spectroscopy showed lower ratios of N-acetyl aspartate to total creatine and higher ratios of choline-containing compounds to total creatine, suggestive of decreased neuronal density and gliosis.

CONCLUSION

Brain MR imaging and MR spectroscopy allow assessment of the severity of FEL and may aid in monitoring the response to treatment.

Congenital malformations causing skull base changes

Recent advances in imaging have enabled both the clinician and radiologist to better understand the therapeutic implications of congenital anomalies involving the skull base. Critical to this understanding is a full knowledge of normal embryologic development, anatomic detail, and clinical manifestations in the wide variety of congenital malformations involving the skull base. This review focuses on individual malformations in terms of their pathophysiology and their imaging findings of critical importance.

Cerebrovascular occlusive disease in childhood

It is clear that for many disorders involving the CNS in children, cerebrovascular occlusion with stroke or strokelike episodes may be an important part of their pathophysiology. In contrast to adults, no single entity is responsible for the majority of strokes in children. The incidence of childhood cerebrovascular occlusive disease is likely much higher than is recorded in the literature if one takes into account conditions in which vascular occlusion plays a significant but secondary role. In some disorders, the occlusive process is often produced by the therapy used to treat the underlying primary disorder (e.g., radiation injury) and often accounts for the greatest morbidity and mortality to the patient. Imaging plays an important role in the detection and follow-up of cerebrovascular occlusive disease in children. A better understanding by the radiologist of the full range of conditions that may be complicated by stroke is important if we are to play a role in early diagnosis and to help guide specific therapy aimed at preventing a recurrence of the event. Imaging has become complex; however, a combination of anatomic and functional imaging is essential in the appropriate workup and management of all children with cerebrovascular occlusive disease.

Meningioangiomatosis of the brain stem. Case report

The case is reported of meningioangiomatosis of the brain stem in a 3 1/2-year-old girl who suffered from vomiting, left facial weakness, difficulty in swallowing, and ataxia. This is believed to be the first reported case of meningioangiomatosis in the brain stem. Computerized tomography showed an intensely enhancing hyperdense mass in the left restiform body. Magnetic resonance imaging revealed that the lesion was isointense to gray matter on the T1-weighted image and hypointense on the T2-weighted image, with a surrounding zone of high T2 signal and intense enhancement. Angiography was normal. Surgical exploration demonstrated an intramedullary firm mass that was partially resected. Histologically, the mass consisted of a low-grade lesion of meningeal origin with spindle cells in a whorling pattern that were occasionally focused around small vessels. On 2-year follow-up imaging, the lesion remains unchanged in size. Certain particularities of this lesion are discussed in the context of the literature.

Comparison of T2-weighted spin-echo and fast spin-echo techniques in the evaluation of myelination

To evaluate T2-weighed fast spin-echo (FSE) and conventional spin-echo (CSE) magnetic resonance (MR) techniques in the assessment of brain myelination, 100 consecutive pediatric patients were imaged prospectively with both CSE and FSE sequences. All patients underwent a routine MR examination that included T2-weighted CSE imaging (imaging time, 10 minutes 21 seconds) and T2-weighted FSE imaging (imaging time, 2 minutes 5 seconds). The two techniques were compared for estimating the degree of myelination (using normal anatomic landmarks) by blind review. With T2-weighted CSE images as the "gold standard" for estimation of normal myelination, FSE images were evaluated to determine if they showed the degree of myelination similarly to CSE images. There was a strong correlation (P < .01) between CSE and FSE images in the estimation of myelination over a wide range of patient ages.

Childhood adrenoleukodystrophy: assessment with proton MR spectroscopy

PURPOSE

Image-guided, single-voxel, localized proton magnetic resonance (MR) spectroscopy was performed to assess white matter in childhood adrenoleukodystrophy (ALD).

MATERIALS AND METHODS

Eleven X-linked ALD subjects, seven with neurologic symptoms or white matter lesions at MR imaging and four asymptomatic patients, were compared with nine aged-matched, healthy volunteers.

RESULTS

Compared with those from normal white matter, MR spectra from white matter lesions (n = 6) showed 65% reduction in the ratio of N-acetyl aspartate (NAA) to total creatine (tCr) (P < .01); 55% increase in the ratio of choline-containing compounds (Cho) to tCr (P < .02); substantial levels of tCr; 94% increase in the ratio of glutamate, glutamine, or inositol to tCr (P < .02); and lactate accumulation in four patients. Patients without brain lesions (n = 4) exhibited a 51% increase in Cho-to-tCr ratio (P < .01) and 11% nonsignificant increase in NAA-to-tCr ratio.

CONCLUSION

Proton MR spectroscopy may prove a valuable technique for noninvasive diagnostic and prognostic assessment of ALD.

Cystic malformations of the posterior fossa: differential diagnosis clarified through embryologic analysis

Cystic or cyst-like malformations of the posterior fossa represent a spectrum of disorders, including the Dandy-Walker malformation, vermian-cerebellar hypoplasia, mega cisterna magna, and arachnoid cyst. Differentiation of these lesions may be difficult with routine cross-sectional imaging; however, an accurate diagnosis is essential for proper treatment planning and genetic counseling. Dandy-Walker malformation is easily diagnosed on the basis of the classic triad: complete or partial agenesis of the vermis, cystic dilatation of the fourth ventricle, and enlarged posterior fossa. Vermian-cerebellar hypoplasia is a general classification that describes congenital malformations with a normal-sized posterior fossa, varying degrees of vermian and cerebellar hypoplasia, and a prominent retrocerebellar cerebrospinal fluid space that communicates freely with a normal or dilated fourth ventricle. Mega cisterna magna can be asymmetric and can manifest apparent mass effect, simulating the appearance of an arachnoid cyst; therefore, ventriculography or cisternography may be needed to demonstrate communication of the cystic mass with the subarachnoid space. A careful review of the embryologic development is essential in understanding these malformations and in making a more accurate radiologic diagnosis.

Localized proton MR spectroscopy of the brain in children

Small-voxel (3.0-8.0 cm3), magnetic resonance (MR) imaging-guided proton MR spectroscopy was performed in 54 patients (aged 6 days to 19 years) with intracranial masses (n = 16), neurodegenerative disorders (n = 34), and other neurologic diseases (n = 4) and in 23 age-matched control subjects without brain disease. A combined short TE (18 msec) stimulated-echo acquisition mode (STEAM) and long TE (135 and/or 270 msec) spin-echo point-resolved spatially localized spectroscopy (PRESS) protocol, using designed radio-frequency pulses, was performed at 1.5 T. STEAM spectra revealed short T2 and/or strongly coupled metabolites; prominent resonances were obtained from N-acetyl aspartate (NAA), choline-containing compounds (Cho), and total creatine (tCr). Lactate was well resolved with the long TE PRESS sequence. Intracranial tumors were readily differentiated from cerebrospinal fluid (CSF) collections. All tumors showed low NAA, high Cho, and reduced tCr levels. Neurodegenerative disorders showed low or absent NAA levels and enhanced mobile lipid, glutamate and glutamine, and inositol levels, consistent with neuronal loss, gliosis, demyelination, and amino acid neurotoxicity. Preliminary experience indicates that proton MR spectroscopy can contribute in the evaluation of central nervous system abnormalities of infants and children.

Cerebral perfusion in children: detection with dynamic contrast-enhanced T2*-weighted MR images

Cerebral perfusion dynamics were assessed with dynamic contrast material-enhanced T2*-weighted magnetic resonance (MR) imaging in 33 subjects aged 3-20 years. Group A (n = 20) had sickle cell anemia without clinical evidence of cerebrovascular disease. Group B (n = 13) consisted of 12 patients with cerebrovascular disease and homozygous sickle cell anemia and one patient without that anemia. All subjects underwent conventional MR imaging and a dynamic study in which a spoiled gradient-echo pulse sequence was used to generate images (acquisition time, 2.5 seconds) during injection of a compact bolus of gadopentetate dimeglumine (0.1 mmol/kg). For qualitative analysis, the dynamic images were displayed in cine mode. Group A demonstrated symmetric sequential region patterns of loss of signal intensity within 10 seconds of injection. Group B exhibited signal loss asymmetries that corresponded to cerebrovascular lesions on conventional MR images. Quantitative analysis enabled estimation of hemodynamic parameters, including relative cerebral blood volume, relative cerebral blood flow, and mean transit time. This method of assessment of cerebral perfusion dynamics complements conventional MR imaging.

Phase III multicenter clinical investigation to determine the safety and efficacy of gadoteridol in children suspected of having neurologic disease

A phase III open-label clinical trial was conducted at 11 institutions to determine the safety and efficacy of gadoteridol in children suspected of having neurologic disease. One hundred three children were included in the safety analysis; 92 were evaluated for efficacy (76 intracranial and 16 spinal examinations). Three adverse events were reported in two children. All adverse events were considered minor and resolved spontaneously without treatment or sequelae. In a comparison of enhanced T1-weighted magnetic resonance images with unenhanced T1- and T2-weighted images, enhancement of disease was noted in 70% of the intracranial and 38% of the spinal examinations. Additional diagnostic information was reported in 82% of the postcontrast intracranial examinations and 62% of the spinal examinations. Use of this additional information contributed to a potential modification of patient diagnosis in 48% of intracranial and 20% of spinal cases with additional information. These results indicate excellent safety and efficacy for use of gadoteridol in children with suspected intracranial or spinal disease.

Evaluation of the craniocervical junction in Down syndrome: correlation of measurements obtained with radiography and MR imaging

Measurement of the atlas-dens interval is the radiographic standard for identification of patients with Down syndrome at high risk for neurologic injury from spinal cord compression. In 17 pediatric patients with Down syndrome, measurements of the atlas-dens interval, distance between the clivus and posterior odontoid process, and width of the neural canal obtained with plain radiographs were compared to predict the width of the subarachnoid space on magnetic resonance (MR) images. In all patients, cervical radiography and craniocervical MR imaging were prospectively performed during lateral flexion and extension. The width of the subarachnoid space was measured with MR imaging. When the 95% confidence interval for correlation coefficients of regression was used, subarachnoid space width on MR images correlated with neural canal width on radiographs better than with either atlas-dens interval or clivus-posterior odontoid process distance (P = .05). Measurement of neural canal width is a better predictor of potential spinal cord compression than the atlas-dens interval or clivus-posterior odontoid process distance and should be emphasized in screening examinations performed with plain radiography.

Clinical proton MR spectroscopy of neurodegenerative disease in childhood

PURPOSE

To determine the contribution of MR spectroscopy in the assessment of childhood neurodegenerative disease.

METHODS

Fifty-one subjects (7 weeks to 17 years of age), 22 with either hereditary (n = 16) or acquired (n = 6) neurodegenerative disorders and 29 age-matched control subjects, were studied with combined proton MR spectroscopy and MR imaging. Single-voxel (2.0-8.0 cc) MR spectra were acquired at 1.5 T, with either short-echo-stimulated echoes and/or long-echo spin echoes.

RESULTS

MR spectra exhibited signals from n-acetyl-, creatine-, and choline-containing compounds, neurotransmitters (glutamate), intracellular mediators (inositols), and glycolytic products (lactate). Abnormal MR spectra in neurodegenerative disorders reflected: demyelination, neuronal loss, and gliosis (increased mobile lipid presence and reduction of n-acetylaspartate to choline); metabolic acidosis (lactate accumulation); and neurotransmitter neurotoxicity (increased glutamate, glutamine, and inositols).

CONCLUSION

Proton MR spectroscopy may complement MR imaging in diagnostic assessment and therapeutic monitoring of neurodegenerative disorders.

Efficacy of gadoteridol for contrast-enhanced magnetic resonance imaging in children

RATIONALE AND OBJECTIVES

This study assesses the efficacy of gadoteridol for contrast-enhanced magnetic resonance imaging (MRI) in children.

METHODS

Patients were examined by MRI before and after receiving 0.10 mmol/kg gadoteridol. Blinded and unblinded readers analyzed brain and spine MRI studies from a multicenter clinical trial involving 101 patients at 11 sites. Ninety-two cases (76 brain, 16 spine) were evaluated by unblinded investigators, and 91 cases (76 brain, 15 spine) were evaluated by three neuroradiologists unaffiliated with any investigational site and blinded to clinical information.

RESULTS

Unblinded readers noted enhancement of brain pathology in 70% of cases versus 50% to 67% among blinded readers. Unblinded readers determined that additional diagnostic information was available after contrast in 82% of brain studies (average, 64% for blinded readers) and would have changed patient diagnoses in 48% of these studies (average, 46% for blinded readers). In spine cases, enhancement of pathology was noted in 38% (unblinded) and 33% to 40% (blinded). Additional diagnostic information was available after contrast in 63% of spine studies (unblinded), or an average of 58% (blinded), and patient diagnoses would have changed in 20% (unblinded), or an average of 59% (blinded).

CONCLUSIONS

Gadoteridol is suitable for enhanced MRI detection, localization, and characterization of central nervous system pathology in children.

Imaging of the brain in children

As proclaimed by the National Institutes of Health, the 1990s have been designated the "decade of the brain." Within this decade, we can expect to see an emergence of functional imaging in addition to the traditional role of anatomic neuroimaging to separate normal from pathologic anatomy. Technical advances continue to redefine the upper limits of resolution for both anatomic and functional imaging and provide us with a greater understanding of how disease processes affect normal brain growth and development. For example, whereas improvements in anatomic resolution will provide greater insight into understanding congenital malformations of the brain, through functional imaging, we will better understand the effect of disease on normal brain growth and development.

Color Doppler US imaging during pediatric neurosurgical and neuroradiologic procedures

Experience with color Doppler imaging (CDI) during 16 pediatric intraoperative and one percutaneous neuro-radiologic procedures was reviewed to assess whether CDI increased the success rate or decreased the procedure time, thus contributing substantially to procedure performance. Intraoperative CDI was used to rapidly identify abnormal vessels or displacement of normal vessels and correlated with preoperative studies. In six cases (four vascular malformations, one mycotic aneurysm, and one hamartoma), surgical resection was altered on the basis of flow information obtained. In one case of percutaneous embolization of a Galenic malformation, CDI provided information contributing to the cessation of the procedure. In six cases (debulking of three gliomas, resection of one vascular malformation, and two biopsies of nonneoplastic conditions), information was added but did not alter the surgical approach. In the remaining four cases (three cerebrospinal fluid drainage procedures, one posterior fossa decompression), no additional information was obtained. Consultation among the ultrasound staff, neuroradiologists, and neurosurgeons before the operative procedure maximized the usefulness of CDI, thus aiding in the success of surgery.