Performance of Standardized Relative CBV for Quantifying Regional Histologic Tumor Burden in Recurrent High-Grade Glioma: Comparison against Normalized Relative CBV Using Image-Localized Stereotactic Biopsies.

BACKGROUND AND PURPOSE: Perfusion MR imaging measures of relative CBV can distinguish recurrent tumor from posttreatment radiation effects in high-grade gliomas. Currently, relative CBV measurement requires normalization based on user-defined reference tissues. A recently proposed method of relative CBV standardization eliminates the need for user input. This study compares the predictive performance of relative CBV standardization against relative CBV normalization for quantifying recurrent tumor burden in high-grade gliomas relative to posttreatment radiation effects. MATERIALS AND METHODS: We recruited 38 previously treated patients with high-grade gliomas (World Health Organization grades III or IV) undergoing surgical re-resection for new contrast-enhancing lesions concerning for recurrent tumor versus posttreatment radiation effects. We recovered 112 image-localized biopsies and quantified the percentage of histologic tumor content versus posttreatment radiation effects for each sample. We measured spatially matched normalized and standardized relative CBV metrics (mean, median) and fractional tumor burden for each biopsy. We compared relative CBV performance to predict tumor content, including the Pearson correlation (r), against histologic tumor content (0%-100%) and the receiver operating characteristic area under the curve for predicting high-versus-low tumor content using binary histologic cutoffs (≥50%; ≥80% tumor). RESULTS: Across relative CBV metrics, fractional tumor burden showed the highest correlations with tumor content (0%-100%) for normalized (r = 0.63, P < .001) and standardized (r = 0.66, P < .001) values. With binary cutoffs (ie, ≥50%; ≥80% tumor), predictive accuracies were similar for both standardized and normalized metrics and across relative CBV metrics. Median relative CBV achieved the highest area under the curve (normalized = 0.87, standardized = 0.86) for predicting ≥50% tumor, while fractional tumor burden achieved the highest area under the curve (normalized = 0.77, standardized = 0.80) for predicting ≥80% tumor. CONCLUSIONS: Standardization of relative CBV achieves similar performance compared with normalized relative CBV and offers an important step toward workflow optimization and consensus methodology.

Acinetobacter sepsis in newborns.

OBJECTIVE: To evaluate the clinico-epidemiological profile of Acinetobacter sepsis in neonates. DESIGN: Retrospective study. SETTING: Level II Neonatal Care Unit. SUBJECTS: 79 neonates with blood culture positive for Acinetobacter. METHODS: Relevant information was collected on a predesigned proforma from the case records and analyzed for clinical and epidemiological characteristics. RESULTS: The incidence of Acinetobacter septicemia was 11.1/1000 live births. Fifty-five babies were hospital born, 24 were outborn. Out of these, 64.6% babies were born at term and 40.5% had a birth weight of 2500 g or more. A cluster of 53 cases was seen between May and September 1995. In cases with early onset sepsis (onset < 7 days of postnatal age), difficulty in breathing (n = 54), chest retraction (n = 35) and refusal to feed (n = 46) were seen more commonly as compared to late onset sepsis (p < 0.05). Complications observed included meningitis, bleeding manifestations and necrotising enterocolitis in three, six and five babies, respectively. The organism was sensitive to ciprofloxacin (96.2%), amikacin (92.4%) and gentamicin (87.3%). A response rate of 52.4% was observed with Ciprofloxacin in babies not responding to cefotaxime and amikacin combination. The overall mortality was 13.9%. CONCLUSION: Nosocomial Acinetobacter sepsis may affect fullterm, appropriate for gestational age babies. Clinical presentation is indistinguishable from Gram negative septicemia. Life threatening complications can also occur. Ciprofloxacin may prove to be useful drug in resistant cases.