Evaluation of SWI in children with sickle cell disease.

BACKGROUND AND PURPOSE: SWI is a powerful tool for imaging of the cerebral venous system. The SWI venous contrast is affected by blood flow, which may be altered in sickle cell disease. In this study, we characterized SWI venous contrast in patients with sickle cell disease and healthy control participants and examined the relationships among SWI venous contrast, and hematologic variables in the group with sickle cell disease. MATERIALS AND METHODS: A retrospective review of MR imaging and hematologic variables from 21 patients with sickle cell disease and age- and sex-matched healthy control participants was performed. A Frangi vesselness filter was used to quantify the attenuation of visible veins from the SWI. The normalized visible venous volume was calculated for quantitative analysis of venous vessel conspicuity. RESULTS: The normalized visible venous volume was significantly lower in the group with sickle cell disease vs the control group (P < .001). Normalized visible venous volume was not associated with hemoglobin, percent hemoglobin F, percent hemoglobin S, absolute reticulocyte count, or white blood cell count. A hypointense arterial signal on SWI was observed in 18 of the 21 patients with sickle cell disease and none of the 21 healthy control participants. CONCLUSIONS: This study demonstrates the variable and significantly lower normalized visible venous volume in patients with sickle cell disease compared with healthy control participants. Decreased venous contrast in sickle cell disease may reflect abnormal cerebral blood flow, volume, velocity, or oxygenation. Quantitative analysis of SWI contrast may be useful for investigation of cerebrovascular pathology in patients with sickle cell disease, and as a tool to monitor therapies. However, future studies are needed to elucidate physiologic mechanisms of decreased venous conspicuity in sickle cell disease.

Diffusion tensor imaging of tract involvement in children with pontine tumors.

BACKGROUND AND PURPOSE: Conventional MR imaging permits subcategorization of brain stem tumors by location and focality; however, assessment of white matter tract involvement by tumor is limited. Diffusion tensor imaging (DTI) is a promising method for visualizing white matter tract tumor involvement supratentorially. We investigated the ability of DTI to visualize and quantify white matter tract involvement in pontine tumors. METHODS AND MATERIALS: DTI data (echo-planar, 1.5T) were retrospectively analyzed in 7 patients with pontine tumors (6 diffuse, 1 focal), 4 patient controls, and 5 normal volunteers. Fractional anisotropy (FA) and apparent diffusion coefficient (ADC) were calculated from the diffusion tensor in 6 regions of interest: bilateral corticospinal tracts, transverse pontine fibers, and medial lemnisci. Relationships between FA and ADC values and results of the neurologic examinations were evaluated. RESULTS: The corticospinal tracts and transverse pontine fibers were affected more often than the medial lemnisci. The DTI parameters (FA and ADC) were significantly altered in all tracts of patients with pontine tumors (P < .05), compared with those values in the control groups. A marginally significant (P = .057) association was seen between the severity of cranial nerve deficit and decreased FA. CONCLUSION: DTI provided superior visualization and quantification of tumor involvement in motor, sensory, and transverse pontine tracts, compared with information provided by conventional MR imaging. Thus, DTI may be a sensitive measure of tract invasion. Further prospective studies are warranted to assess the ability of DTI to delineate tumor focality and improve risk stratification in children with pontine tumors.

Diffuse CNS vasculopathy with chronic Epstein-Barr virus infection in X-linked lymphoproliferative disease.

We report a patient with X-linked lymphoproliferative disease (XLP) who developed multiple central nervous system (CNS) manifestations of Epstein-Barr virus infection. XLP, or Duncan syndrome, is a rare inherited disorder characterized by the inability to clear Epstein-Barr virus infection. In addition to Epstein-Barr virus encephalitis, CNS lymphoproliferative disease, and lymphoma, this patient also developed MR angiographic evidence of diffuse fusiform aneurysmal dilation of intracranial vessels.

Encephalopathy in pediatric patients after allogeneic hematopoietic stem cell transplantation is associated with a poor prognosis.

SUMMARY: Encephalopathy is a poorly characterized complication of hematopoietic stem cell transplantation (HSCT). No comprehensive report of encephalopathy exists for children, and the literature contains only a few for adults. We analyzed a large cohort of 405 pediatric patients who underwent allogeneic HSCT during a 10-year period and identified 26 patients (6.4%) who experienced encephalopathy. Identifiable causes of encephalopathy included infection (n=5), single or multiorgan failure (n=4), medication-related complications (n=3), nonconvulsive seizures (n=4), acute disseminated encephalomyelitis (n=2), thrombotic thrombocytopenic purpura (n=2), and stroke (n=1). We were unable to identify the etiology of encephalopathy in five (19%) patients. The prognosis for pediatric patients with encephalopathy was poor: only four (15%) experienced complete neurologic recovery, and 10 (38%) patients experienced partial recovery with residual neurologic deficits. Nine (35%) patients with complete or partial recovery survive long term. A total of 17 patients died; one died of progressive encephalopathy, and 16 died of either relapse of primary disease or toxicity. MRI, CSF analysis including molecular testing for infectious pathogens, and brain biopsy were helpful in obtaining a diagnosis in most of our patients. However, a standardized approach to accurate and timely diagnosis and treatment is needed to improve outcome in these patients.

Improved cerebrovascular patency following therapy in patients with sickle cell disease: initial results in 4 patients who received HLA-identical hematopoietic stem cell allografts.

To test whether magnetic resonance angiography can document the evolution of vasculopathy in patients with sickle cell disease, we reviewed records to identify all patients who underwent magnetic resonance angiography from 1993 to 1999. Of 512 angiographies performed, 105 were of sickle cell disease patients, and 24 sickle cell disease patients 7 years of age or older underwent baseline and follow-up examinations. Films were paired by patient, blinded as to examination date and treatment, and quantitatively compared. Four patients who received allogeneic bone marrow transplantation were compared to 7 patients who received other therapy and to 13 untreated patients. Quantitative analysis revealed a 10% increase in the measured diameter of 64 vessels (p = 0.001) following any treatment. Patients who had undergone allogeneic bone marrow transplantation exhibited a 12% increase in the lumen of 22 vessels (p = 0.041), whereas patients treated with chronic transfusion or hydroxyurea exhibited an 8% increase in 42 vessels (p = 0.016). In 2 patients with severe stenosis, the artery normalized after transplantation, and the blood flow rate was reduced in all patients who underwent transplantation. In untreated patients, there was a trend for the size of the arterial lumen to decrease, which is consistent with disease progression. Results suggest that treatment can reverse progression of vasculopathy. Bone marrow transplantation may enable stenoses to heal and can substantially reduce cranial blood velocity, suggesting that allogeneic bone marrow transplantation may prevent infarction or brain damage.

Epstein-Barr virus-targeted therapy for AIDS-related primary lymphoma of the central nervous system.

Epstein-Barr virus (EBV) targeted therapeutic strategies for viral associated malignant diseases have received only perfunctory consideration, first, because latent herpesviruses have been intractable to antiviral chemotherapy and, second, because the role EBV has in maintenance of the malignant cell phenotype has been uncertain. Two patients with EBV related primary central nervous system lymphoma (PCNSL) in the setting of advanced AIDS, were treated with low dose hydroxyurea based on in vitro anti-EBV activity. The responses obtained here suggest the promise of antiviral approaches in select cancers.

Fatal fat embolism in a patient with sickle-beta+ thalassemia.

We describe a case of an adolescent with sickle-beta+ thalassemia who developed fatal fat embolism syndrome. After presenting with bone pain, the patient developed mental status changes, hypoxemia, and died following cardiorespiratory arrest.

Imaging features of ovarian metastases from colonic adenocarcinoma in adolescents.

This paper describes the imaging features of ovarian metastases from adenocarcinoma of the colon in adolescent females. We reviewed retrospectively abdominal and pelvic computed tomographic and pelvic ultrasound examinations, histologic slices, and clinical charts of six adolescent females with ovarian metastases secondary to adenocarcinoma of the colon. One patient had ovarian metastasis at presentation and was presumed to have a primary ovarian tumor. The ovarian metastases were either solid (n = 3), complex with both solid and cystic components (n = 2), or multilocular cysts (n = 1). The ovarian lesions were large, ranging from 6 cm to 18 cm in diameter. Colorectal carcinoma in adolescent females is frequently associated with ovarian metastases. One imaging characteristic differs in adult and adolescent ovarian metastases, although they do have features in common: in adolescents, a smaller proportion of colorectal ovarian metastases are multicystic (17%) compared with the adult series (45%). These lesions are frequently large and may be complex, multicystic, or solid. Although it is a rare disease, the differential diagnosis of adnexal masses in adolescent females should include ovarian metastases from adenocarcinoma of the colon.

The unfolding of trp aporepressor as a function of pH: evidence for an unfolding intermediate.

The urea-induced unfolding of trp aporepressor from Escherichia coli has been studied as a function of pH from 2.5 to 12.0 at 25 degrees C. At pH 7 and above, the unfolding transition, as monitored by changes in the fluorescence intensity at 360 nm, shows a single transition. At low pH, the transition again appears to be a single transition. In the range of 3.5-6.0, the transition is biphasic, indicating the existence of a folding intermediate. The transitions have also been studied using circular dichroism and size exclusion chromatography. The data were fitted by a model in which the dimeric protein first unfolds to form structured monomers, followed by the unfolding of the monomers. From fits with this "folded monomers" model, the free energy change for the dimer<-->monomer dissociation becomes less positive as pH is decreased; the free energy change for the unfolding of the monomers is essentially independent of pH. An alternate model is one in which the dimer first undergoes a transition to a partially unfolded dimeric state, with this intermediate then denaturing to unfolded monomers. Both models give adequate fits to the data obtained at a single protein concentration. From a study of the concentration dependence of the urea-induced unfolding at pH 5, the "folded monomers" model is found to be more consistent with the data. Size exclusion chromatography data support the description of the intermediate state, which is the most populated state at low pH in the absence of urea, as being a relatively compact monomer.(ABSTRACT TRUNCATED AT 250 WORDS)

The New Adult Reading Test-Revised: accuracy in estimating WAIS-R IQ scores obtained 3.5 years earlier from normal older persons.

Scores on the New Adult Reading Test-Revised (NART-R) were used to estimate WA1S-R IQ scores obtained approximately 3.5 years earlier from 54 normal older persons (M = 68 y; SD = 8.6). NART-R estimated IQ scores correlated reliably with earlier obtained IQ scores: FS1Q r = 0.70; VIQ r = 0.68; PIQ r = 0.61 (all p's < 0.05). NART-R estimated FSIQs underpredicted obtained FSIQs by an average of 3.8 points (SD = 9.3). The correlation between estimated and obtained FSIQ is fairly high and estimated FSIQ is reasonably close to obtained IQ, despite the considerable length of time passing between WAIS-R and NART-R administration. These results represent the first confirmation of the retrospective accuracy of the NART-R in estimating WAIS-R scores across time, a previously untested but critical assumption for clinical application of this approach. These results also apparently represent the first cross-validation of the NART-R in a sample of older Americans. These results suggest that further research on the clinical utility of the NART-R is warranted.

Multicentric squamous cell carcinoma in situ resembling Bowen's disease in cats.

Multicentric squamous cell carcinoma in situ was studied in 12 cats (eight castrated males and four spayed females). The neoplasms occurred in middle-aged to old (mean age = 12 years) mixed-breed cats with a variety of hair-coat colors. The lesions were found in haired pigmented regions of the skin, including the trunk, limbs, feet, head, and neck, and were unrelated to exposure to sunlight. Lesions occurred at multiple sites in nine cats and at solitary sites in three cats and were from 0.5 cm to 3.0 cm in diameter, irregular, slightly elevated, plaque-like or papillated, and partially alopecic. Histologically, the lesions consisted of sharply demarcated regions of neoplastic, keratinocytic infiltration of the epidermal and follicular infundibular epithelium. Neoplastic cells were confined to the epithelium without frank invasion of the dermis. Two histologic subclasses of multicentric squamous cell carcinoma in situ were identified, the irregular nonhyperkeratotic type and the verrucous hyperkeratotic type. Three cats also had invasive squamous cell carcinoma adjacent to lesions characteristic of multicentric squamous cell carcinoma in situ. Grossly, these were solitary 2.0-4.0 cm-diameter firm, crusted, crateriform cutaneous masses. During follow-up periods of 4 to 20 months (mean follow-up period = 11 months), neoplasms did not recur locally after surgical excision; however, similar lesions developed at new sites in four cats.(ABSTRACT TRUNCATED AT 250 WORDS)

Bone tumors other than osteosarcoma after retinoblastoma.

BACKGROUND: The most frequent second malignant neoplasm after retinoblastoma is osteosarcoma, which may be associated with radiation therapy or arise de novo in patients with bilateral retinoblastoma. METHODS: Clinical, pathologic, and diagnostic imaging findings in two patients with Ewing sarcoma (ES) and one with peripheral neuroepithelioma (PN) are presented. RESULTS: Second malignant neoplasms located in the extremities or pelvis were seen 12-18 years after initial diagnosis of unilateral (two patients) or bilateral (one patient) retinoblastoma. The patients with unilateral retinoblastoma were treated by enucleation only; the other received ocular radiation therapy and chemotherapy. To the knowledge of the authors, this is the first documentation of round blue cell tumor after unilateral retinoblastoma. CONCLUSIONS: ES and PN should be included in the differential diagnosis of malignant neoplasms occurring after treatment of unilateral or bilateral retinoblastoma.

The neuroethological approach to obsessive-compulsive disorder.

Advances in the neurobiology of obsessive-compulsive disorder (OCD) have raised the possibility that animal models in general and neuroethological models in particular may be useful in understanding and investigating this illness. One neuroethologically oriented model is that of canine acral lick dermatitis. In this report, we review the advantages and limitations of animal models of OCD. Preliminary data on the use of fluoxetine in the treatment of canine acral lick dermatitis are discussed.

Bronchiolitis obliterans-organizing pneumonia (BOOP) in children with malignant disease.

Four patients who had completed chemotherapy for malignant disease are presented. Unexpected findings of pulmonary infiltrates on chest radiographs of two patients and solitary and/or confluent nodules on CT in all four led to open lung biopsy. Histologic diagnosis in each case was bronchiolitis obliterans-organizing pneumonia (BOOP). This usually innocuous disorder can be differentiated histologically from the more severe pure bronchiolitis obliterans and should be considered in the differential diagnosis of pulmonary lesions associated with malignant disease.