BACKGROUND: Cognitive and language impairments constitute the majority of disabilities observed in preterm infants. It remains unclear if diffuse excessive high signal intensity on magnetic resonance imaging at term represents delayed white matter maturation or pathology. METHODS: We hypothesized that diffusion tensor imaging based objectively quantified diffuse excessive high signal intensity measures at term will be strong predictors of cognitive and language development at 2 years in a cohort of 41 extremely low birth weight (<= 1000 g) infants. Using an automated probabilistic atlas, mean diffusivity maps were used to objectively segment and quantify diffuse excessive high signal intensity volume and mean, axial, and radial diffusivity measures. Standardized neurodevelopment was assessed at 2 years of age using the Bayley Scales of Infant Development, third edition. RESULTS: Thirty-six of the 41 infants (88%) had complete developmental data at follow-up. Objectively quantified diffuse excessive high signal intensity volume correlated significantly with cognitive and language scores at 2 years (P < 0.001 for both). The sum values of the three diffusivity measures in detected diffuse excessive high signal intensity regions also correlated significantly with the Bayley scores (r(2) 34.7%; P < 0.001 for each). Infants in the highest quartile for diffuse excessive high signal intensity volumes had scores between 19 and 24 points lower than infants in the lowest quartile (P < 0.01). When diagnosed subjectively by neuroradiologists however, Bayley scores were not significantly lower in infants with extensive diffuse excessive high signal intensity. CONCLUSIONS: These findings lend further evidence that diffuse excessive high signal intensity is pathologic and that objectively quantified diffusion-based diffuse excessive high signal intensity volume at term is associated with cognitive and language impairments. Our approach could be used for risk stratification and early intervention for such high-risk extremely preterm infants.

We present a 14-year-old female patient with a 2 yr history of positional headache secondary to spontaneous diffuse cerebrospinal fluid (CSF) leaks. We treated the leak with an epidural blood patch which was radioactively labeled by a well-established nuclear medicine technique. Because spontaneous CSF leaks were frequently multifocal or diffuse throughout the spine, the extent of coverage or distribution of an epidural patch was generally determined by best estimate. Traditional radiographic contrast media mixed with the blood cells had been used to monitor the patch coverage and it is questionable whether the contrast can be representative of the cell distribution. We applied a nuclear medicine technique to label the autologous red blood cells to monitor the range of spinal cord coverage of each epidural patch. After two visible epidural patches covered both the lumbar and thoracic spine, computed tomography myelogram demonstrated significantly decreased leakage when compared to the pre-patch images. However, the patient's symptoms remained essentially unchanged in the long term, which is consistent with refractory spontaneous CSF leaks. We believe that this sophisticated nuclear medicine blood labeling technique is a simple and accurate way to monitor the true cell coverage of the spine and the pattern of distribution.

OBJECTIVE. Our goal was to relate postnatal dexamethasone therapy in extremely low birth weight infants (birth weight of ≤1000 g) to their total and regional brain volumes, as measured by volumetric MRI performed at term-equivalent age. METHODS. Among 53 extremely low birth weight infants discharged between June 1 and December 31, 2003, 41 had high-quality MRI studies; 30 of those infants had not received postnatal steroid treatment and 11 had received dexamethasone, all after postnatal age of 28 days, for a mean duration of 6.8 days and a mean cumulative dose of 2.8 mg/kg. Anatomic brain MRI scans obtained at 39.5 weeks (mean) postmenstrual age were segmented by using semiautomated and manual, pretested, scoring algorithms to generate three-dimensional cerebral component volumes. Volumes were adjusted according to postmenstrual age at MRI. RESULTS. After controlling for postmenstrual age at MRI, we observed a 10.2% smaller total cerebral tissue volume in the dexamethasone-treated group, compared with the untreated group. Cortical tissue volume was 8.7% smaller in the treated infants, compared with untreated infants. Regional volume analysis revealed a 20.6% smaller cerebellum and a 19.9% reduction in subcortical gray matter in the dexamethasone-treated infants, compared with untreated infants. In a series of regression analyses, the reductions in total cerebral tissue, subcortical gray matter, and cerebellar volumes associated with dexamethasone administration remained significant after controlling not only for postmenstrual age but also for bronchopulmonary dysplasia and birth weight. CONCLUSIONS. We identified smaller total and regional cerebral tissue volumes in extremely low birth weight infants treated with relatively conservative regimens of dexamethasone. These volume deficits may be the structural antecedents of neuromotor and cognitive abnormalities reported after postnatal dexamethasone treatment.

The anterior pituitary gland may exhibit high signal on T1-weighted (T1w) images and/or low signal on T2-weighted (T2w) images in several normal and pathological states. High T1w signal may be seen in normal fetuses, neonates, and in pregnant and postpartum women. It may also occur in Rathke's cleft cyst, craniopharyngioma, subacute hemorrhage, manganese deposition, melanoma, dermoid, and lipoma. Low T2w signal may be seen in hemorrhage, calcification, cystic lesion, hemochromatosis, melanoma, and vascular lesions. These are described and illustrated.

Fifteen patients who sustained spinal cord trauma were evaluated by MR within 72 hours of injury. Nine patients had hemorrhagic and six had nonhemorrhagic traumatic spinal cord lesions. Three patients with hemorrhagic and all six patients with nonhemorrhagic lesions showed some degree of neurological improvement on follow-up examinations. In two of the three patients with hemorrhagic lesions who improved, the hemorrhage was extensive. This supports the observation that hemorrhagic lesions are not always associated with a poor clinical outcome.

PURPOSE: To describe the MR appearance of cystic meningiomas, and to correlate the MR appearance with the surgical and neuropathologic findings. METHODS: Eight patients with cysts associated with meningiomas were studied on a 1.5-T MR system. Unenhanced sagittal T1- and axial T2-weighted images were obtained in all patients. Axial and coronal gadopentetate dimeglumine-enhanced T1-weighted spin-echo images were obtained in seven patients. Additional sagittal T1-weighted spin-echo contrast-enhanced images were obtained in four patients. RESULTS: The cystic components were intratumoral and eccentric in two cases, intraparenchymal in one case, and extraparenchymal (trapped cerebrospinal fluid) in five cases. Cyst wall enhancement was present in two of seven cases performed with intravenous gadopentetate dimeglumine. There was no correlation between cyst signal intensity and cyst content. A preoperative diagnosis of cystic meningioma was possible in all eight cases. CONCLUSIONS: MR demonstrates the extradural location of the tumor and its cystic component, correlates well with the surgical presentation and the neuropathologic results, and allows the preoperative diagnosis of cystic meningioma based on the MR findings. Division into three types of cysts aids the neurosurgeon, who must decide whether total resection is feasible. To obtain total resection and reduce the risk of recurrence with an intratumoral cyst, the surgeon must ensure that the plane of resection is in fact between the thin enhancing membrane of the tumor cyst and the adjacent arachnoid. In cases in which the cyst is trapped cerebrospinal fluid or intraparenchymal in location, the cyst wall adjacent to or within the brain parenchyma is not included in the resection.

We present two cases of ventricular obstruction in which shunting of intracranial cysts resulted in the unexpected finding of ventricular enlargement. By imaging criteria this suggested shunt malfunction [corrected]; however, the clinical presentation dramatically improved. The probable mechanism for this diagnostic pitfall is discussed.

PURPOSE To describe the involvement of the cerebellum by a gliotic and demyelinating process in Langerhans cell histiocytosis. METHODS A retrospective analysis of all (N = 30) cases of Langerhans cell histiocytosis followed at our institution since 1975 yielded four patients with CT and/or MR evidence of cerebellar abnormalities. RESULTS Four patients manifested strikingly similar findings of symmetric nonenhancing hypodensities in the dentate nuclei region of the cerebellum, which were hypointense on short-repetition-time/short-echo-time MR and hyperintense on long-repetition-time/long-echo-time MR. Biopsy in one patient yielded areas of demyelination, cell loss, and gliosis without histiocytic infiltration. CONCLUSION Langerhans cell histiocytosis involves the cerebellum in a specific and poorly understood manner. Lesions on imaging may precede clinical findings by years. Lesions may occur in patients who have never experienced radiation therapy and may act as a marker for eventual central nervous system deterioration.

PURPOSE: To investigate the value of MR in differentiating patients with primary polydipsia, who have an intact neurohypophyseal system, from those with central diabetes insipidus, who have impaired synthesis and/or release of vasopressin. METHODS: Eighteen patients with clinically significant hypotonic polyuria were diagnosed endocrinologically as having primary polydipsia or diabetes insipidus (central or nephrogenic). These patients, and 92 patients without sellar disease, were then imaged with 1.5-T, T1-weighted, thin sagittal sections without gadolinium contrast. RESULTS: Normal hyperintense signal of the neurohypophysis was present in 90 of 92 patients without sellar disease. The signal was also present in all six patients with primary polydipsia. In contrast, the hyperintense signal was absent in all eight patients with central diabetes insipidus. Three of the four patients with nephrogenic diabetes insipidus also had an absent hyperintense signal. CONCLUSION: T1-weighted MR may prove important in differentiating patients with central diabetes insipidus from those with primary polydipsia.

Proboscis lateralis is a rare craniofacial malformation. We present a case in a 1-week-old male infant, describe the clinical and imaging findings, and discuss the pertinent embryology. MR and CT proved to be complementary: CT provided anatomic detail in bone, defined the nasal cavity, and aided in determining the relationship of the proboscis and orbit; MR clarified the relationship of the proboscis to the orbit and skull base, and the relationships of normal brain to the dysplastic ethmoid centers.

Gross and histologic analyses of 78 carotid endarterectomy specimens removed from 71 patients showed intraplaque hemorrhage (subintimal hemorrhage) and necrosis in 74 (94.8%); all but 3 were symptomatic. In 66 (95.6%) of 69 carotid arteries with lucent plaques on intravenously enhanced computed tomography (CT), the presence of subintimal hemorrhage and necrosis and the maximal areas of involvement were accurately predicted preoperatively. The pathologic zones were readily identified as areas of circumferential and eccentric focal mural thickening frequently associated with moderate to severe luminal stenosis. Local, expansile areas of intraplaque hemorrhage were consistently observed in 30 (39%) atheromatous plaques causing significant stenosis in marked disparity to the contralateral asymptomatic carotid artery as shown by angiography (including 7 without CT examinations) and CT. There was preponderant involvement of the distal common carotid, carotid bifurcation and proximal internal carotid artery segments. Most patients with hemorrhagic and necrotic plaques had ipsilateral recent (within 6 weeks) neurologic manifestations predominantly in the form of transient ischemic attack, amaurosis fugax and stroke. Our experience reflects the high incidence of intraplaque hemorrhage in carotid related cerebroembolic events. Its presence can be consistently implicated by the demonstration of a markedly lucent plaque on CT and the observation of a symptomatic focal carotid stenosis in marked disparity to the contralateral asymptomatic carotid artery on CT and angiography.

The preoperative MR findings in 11 patients, all of whom had developed recurrent low back pain after surgery for herniated lumbar intervertebral disk, were correlated with the surgical findings to determine possible criteria for distinguishing recurrent disk herniation from postoperative scar (extradural fibrosis). The preoperative MR findings agreed with the surgical findings in seven of eight patients with recurrent disk herniation and in six of nine individuals with extradural fibrosis. The most important parameters in differentiating recurrent herniated disk from extradural scar were the configuration and margination of the extradural mass rather than its signal characteristics. The most reliable MR sign for recurrent herniated disk was the presence of a sharply marginated focal polypoid disk protrusion beyond the posterior margins of the adjacent vertebral bodies shown to best advantage on sagittal T1- and T2-weighted and axial T1-weighted spin-echo MR images. Disk herniations usually maintained isointensity with the intervertebral disk of origin, while extradural fibrosis exhibited variable signal intensity. The preoperative diagnosis of extradural fibrosis on MR was based primarily on its irregular configuration and extension. This study suggests that preoperative differentiation between scar and recurrent herniated disk is possible with MR when morphology and topography are considered in addition to signal intensity.

Two previously well term neonates whoe presented with seizures are described: one with thalamic hemorrhage and the other with thalamic and caudate hemorrhage. These 2 patients were the only neonates found with thalamic hemorrhage in a review of 54 term infants with intracranial hemorrhage at The Hospital for Sick Children over a 10 year period (1976 – 1986). Partial seizures occurred at 5 and 7 days after birth and were easily controlled. Prognosis was generally good in these 2 patients, as well as in 4 previously reported patients.

We describe a technique for performing intravenous digital subtraction arteriography by peripheral injection and review our experience of 504 studies in 469 patients. The technique gave adequate opacification for anatomical definition of vessels in 93% of patients studied and was suitable for studies of the pulmonary arteries and left ventricle as well as the major systemic arteries. The chief causes of failure were impaired cardiac performance (2.4%) and poor patient cooperation (1.4%). Premature termination was caused by angina pectoris in 1.6% of our cases. These limitations apply also to central venous injection.

A comprehensive but basic and updated systematic radiographic approach to various pain-producing thoracolumbar diseases is presented. The advantages and limitations of available diagnostic modalities are discussed in relation to the clinically considered etiologies.