Three-dimensional surface reconstruction within noncontact diffuse optical tomography using structured light

A main field in biomedical optics research is diffuse optical tomography, where intensity variations of the transmitted light traversing through tissue are detected. Mathematical models and reconstruction algorithms based on finite element methods and Monte Carlo simulations describe the light transport inside the tissue and determine differences in absorption and scattering coefficients. Precise knowledge of the sample's surface shape and orientation is required to provide boundary conditions for these techniques. We propose an integrated method based on structured light three-dimensional (3-D) scanning that provides detailed surface information of the object, which is usable for volume mesh creation and allows the normalization of the intensity dispersion between surface and camera. The experimental setup is complemented by polarization difference imaging to avoid overlaying byproducts caused by inter-reflections and multiple scattering in semitransparent tissue.

Loss of heterozygosity 1p36 and 19q13 is a prognostic factor for overall survival in patients with diffuse WHO grade 2 gliomas treated without chemotherapy

PURPOSE: This study was conducted to elucidate the impact of loss of heterozygosity (LOH) for chromosomes 1p36 and 19q13 on the overall survival of patients with diffusely infiltrating WHO grade 2 gliomas treated without chemotherapy. PATIENTS AND METHODS: We assessed the LOH status of tumors from patients harboring WHO grade 2 gliomas diagnosed between 1991 and 2000. Patients were either followed after initial biopsy or treated by surgery and/or radiation therapy (RT). Overall survival, time to malignant transformation, and progression-free survival were last updated as of March 2005. RESULTS: Of a total of 79 patients, LOH 1p36 and LOH 19q13 could be assessed in 67 and 66 patients, respectively. The median follow-up after diagnosis was 6 years. Loss of either 1p or 19q, in particular codeletion(s) at both loci, was found to positively impact on both overall survival (log-rank P < .01), progression-free survival, and survival without malignant transformation (P < .05). Tumor volume (P < .0001), neurologic deficits at diagnosis (P < .01), involvement of more than one lobe (P < .01), and absence of an oligodendroglial component (P < .05) were also predictors of shorter overall survival. The extent of surgery was similar in patients with or without LOH 1p and/or 19q; RT was more frequently resorted to for patients without than for patients with LOH 1p/19q (30% v 60%). CONCLUSION: The presence of LOH on either 1p36 or 19q13, and in particular codeletion of both loci is a strong, nontreatment-related, prognostic factor for overall survival in patients with diffusely infiltrating WHO grade 2 gliomas.

Microcystic serous cystadenoma of the pancreas: a report of two cases with one of diffuse presentation

Microcystic adenoma or serous cystadenoma is an uncommon tumor and accounts for 1-2% of the exocrine neoplasms of the pancreas. Usually unifocal, they present as single, large, well-demarcated multiloculated cystic tumors, ranging in size from 1 to 25 cm. Multifocal variants or diffuse serous cystadenomas are extremely rare. We present 2 cases of which 1 is a diffuse variant affecting the body, tail and part of the neck of the pancreas. In both the patients the tumors were detected incidentally. We highlight on the diffuse variant in view of its rarity and present a review of literature. In this case the entire body and tail of the pancreas was spongy replaced by multicystic lobules and hyalinized fibrocollagenous stroma. The cysts were lined by low cuboidal glycogen containing bland cells. Such a unique presentation wherein the entire body and tail of the pancreas is replaced with multiple cysts is a diffuse presentation of microcystic adenoma and a search through literature revealed only 7 such cases among the 15 cases with multifocal presentation reported.

Online correlation of spontaneous arterial and intracranial pressure fluctuations in patients with diffuse severe head injury

Determination of relevant clinical monitoring parameters for helping guide the intensive care therapy in patients with severe head injury, is one of the most demanding issues in neurotrauma research. New insights into cerebral autoregulation and metabolism have revealed that a rigid cerebral perfusion pressure (CPP) regimen might not be suitable for all severe head injured patients. We thus developed an online analysis technique to monitor the correlation (AI rho) between the spontaneous fluctuations of the mean arterial blood pressure (MABP) and the intracranial pressure (ICP). In addition, brain tissue oxygen (PtiO2) and metabolic microdialysate measures including glucose and lactate were registered. We found that in patients with good outcome, the AI rho values were significantly lower as compared with patients with poor outcome. Accordingly, microdialysate glucose and lactate were significantly higher in the good outcome group. We conclude that online determination of AI rho offers a valuable additional and technically easily performable tool for guidance of therapy in patients with severe head injury.

Oxygen-sensitive 3He-MRI in bronchiolitis obliterans after lung transplantation

Oxygen-sensitive 3He-MRI was studied for the detection of differences in intrapulmonary oxygen partial pressure (pO2) between patients with normal lung transplants and those with bronchiolitis obliterans syndrome (BOS). Using software developed in-house, oxygen-sensitive 3He-MRI datasets from patients with normal lung grafts (n = 8) and with BOS (n = 6) were evaluated quantitatively. Datasets were acqiured on a 1.5-T system using a spoiled gradient echo pulse sequence. Underlying diseases were pulmonary emphysema (n = 10 datasets) and fibrosis (n = 4). BOS status was verified by pulmonary function tests. Additionally, 3He-MRI was assessed blindedly for ventilation defects. Median intrapulmonary pO2 in patients with normal lung grafts was 146 mbar compared with 108 mbar in patients with BOS. Homogeneity of pO2 distribution was greater in normal grafts (standard deviation pO2 34 versus 43 mbar). Median oxygen decrease rate during breath hold was higher in unaffected patients (-1.75 mbar/s versus -0.38 mbar/s). Normal grafts showed fewer ventilation defects (5% versus 28%, medians). Oxygen-sensitive 3He-MRI appears capable of demonstrating differences of intrapulmonary pO2 between normal lung grafts and grafts affected by BOS. Oxygen-sensitive 3He-MRI may add helpful regional information to other diagnostic techniques for the assessment and follow-up of lung transplant recipients.

Influence of oxygen therapy on glucose-lactate metabolism after diffuse brain injury

OBJECT: Severe traumatic brain injury (TBI) imposes a huge metabolic load on brain tissue, which can be summarized initially as a state of hypermetabolism and hyperglycolysis. In experiments O2 consumption has been shown to increase early after trauma, especially in the presence of high lactate levels and forced O2 availability. In recent clinical studies the effect of increasing O2 availability on brain metabolism has been analyzed. By their nature, however, clinical trauma models suffer from a heterogeneous injury distribution. The aim of this study was to analyze, in a standardized diffuse brain injury model, the effect of increasing the fraction of inspired O2 on brain glucose and lactate levels, and to compare this effect with the metabolism of the noninjured sham-operated brain. METHODS: A diffuse severe TBI model developed by Foda and Maramarou, et al., in which a 420-g weight is dropped from a height of 2 m was used in this study. Forty-one male Wistar rats each weighing approximately 300 g were included. Anesthesized rats were monitored by placing a femoral arterial line for blood pressure and blood was drawn for a blood gas analysis. Two time periods were defined: Period A was defined as preinjury and Period B as postinjury. During Period B two levels of fraction of inspired oxygen (FiO2) were studied: air (FiO2 0.21) and oxygen (FiO2 1). Four groups were studied including sham-operated animals: air-air-sham (AAS); air-O2-sham (AOS); air-air-trauma (AAT); and air-O2-trauma (AOT). In six rats the effect of increasing the FiO2 on serum glucose and lactate was analyzed. During Period B lactate values in the brain determined using microdialysis were significantly lower (p < 0.05) in the AOT group than in the AAT group and glucose values in the brain determined using microdialysis were significantly higher (p < 0.04). No differences were demonstrated in the other groups. Increasing the FiO2 had no significant effect on the serum levels of glucose and lactate. CONCLUSIONS: Increasing the FiO2 influences dialysate glucose and lactate levels in injured brain tissue. Using an FiO2 of 1 influences brain metabolism in such a way that lactate is significantly reduced and glucose significantly increased. No changes in dialysate glucose and lactate values were found in the noninjured brain.