An integrated assessment of environmental, economic, social and technological parameters of source separated and conventional sanitation concepts: A contribution to sustainability analysis.

Resource recovery and reuse from domestic wastewater has become an important subject for the current development of sanitation technologies and infrastructures. Different technologies are available and combined into sanitation concepts, with different performances. This study provides a methodological approach to evaluate the sustainability of these sanitation concepts with focus on resource recovery and reuse. St. Eustatius, a small tropical island in the Caribbean, was used as a case study for the evaluation. Three source separation-community-on-site and two combined sewerage island-scale concepts were selected and compared in terms of environmental (net energy use, nutrient recovery/reuse, BOD/COD, pathogens, and GHG emission, land use), economic (CAPEX and OPEX), social cultural (acceptance, required competences and education), and technological (flexibility/adaptability, reliability/continuity of service) indicators. The best performing concept, is the application of Upflow Anaerobic Sludge Bed (UASB) and Trickling Filter (TF) at island level for combined domestic wastewater treatment with subsequent reuse in agriculture. Its overall average normalised score across the four categories (i.e., average of average per category) is about 15% (0.85) higher than the values of the remaining systems and with a score of 0.73 (conventional activated sludge - centralised level), 0.77 (UASB-septic tank (ST)), 0.76 (UASB-TF - community level), and 0.75 (ST - household level). The higher score of the UASB-TF at community level is mainly due to much better performance in the environmental and economic categories. In conclusion, the case study provides a methodological approach that can support urban planning and decision-making in selecting more sustainable sanitation concepts, allowing resource recovery and reuse in small island context or in other contexts.

Assessment of nitrogen and phosphorus flows in agricultural and urban systems in a small island under limited data availability.

Nitrogen (N) and phosphorus (P) are two essential macronutrients required in agricultural production. The major share of this production relies on chemical fertilizer that requires energy and relies on limited resources (P). Since these nutrients are lost to the environment, there is a need to shift from this linear urban metabolism to a circular metabolism in which N and P from domestic waste and wastewater are reused in agriculture. A first step to facilitate a transition to more circular urban N and P management is to understand the flows of these resources in a coupled urban-agricultural system. For the first time this paper presents a Substance Flow Analysis (SFA) approach for the assessment of the coupled agricultural and urban systems under limited data availability in a small island. The developed SFA approach is used to identify intervention points that can provide N and P stocks for agricultural production. The island of St. Eustatius, a small island in the Caribbean, was used as a case study. The model developed in this study consists of eight sub-systems: agricultural and natural lands, urban lands, crop production, animal production, market, household consumption, soakage pit and open-dump landfill. A total of 26 flows were identified and quantified for a period of one year (2013). The results showed that the agricultural system is a significant source for N and P loss because of erosion/run-off and leaching. Moreover, urban sanitation systems contribute to deterioration of the island's ecosystem through N and P losses from domestic waste and wastewater by leaching and atmospheric emission. Proposed interventions are the treatment of blackwater and greywater for the recovery of N and P. In conclusion, this study allows for identification of potential N and P losses and proposes mitigation measures to improve nutrient management in a small island context.

A new approach to nationwide sanitation planning for developing countries: Case study of Indonesia.

Many developing countries struggle to provide wastewater and solid waste services. The backlog in access has been partly attributed to the absence of a functional sanitation planning framework. Various planning tools are available; however a comprehensive framework that directly links a government policy to nationwide planning is missing. Therefore, we propose a framework to facilitate the nationwide planning process for the implementation of wastewater and solid waste services. The framework requires inputs from government planners and experts in the formulation of starting points and targets. Based on a limited number of indicators (population density, urban functions) three outputs are generated. The first output is a visualization of the spatial distribution of wastewater and solid waste systems to support regional priority setting in planning and create awareness. Secondly, the total number of people served, budget requirements and distribution of systems is determined. Thirdly, the required budget is allocated to the responsible institution to assure effective implementation. The determined budgets are specified by their beneficiaries, distinguishing urban, rural, poor and non-poor households. The framework was applied for Indonesia and outputs were adopted in the National Development Plan. The required budget to reach the Indonesian government's 2019 target was determined to be 25 billion US$ over 5years. The contribution from the national budget required a more than fivefold increase compared to the current budget allocation in Indonesia, corresponding to an increase from 0.5 to 2.7 billion US$ per year. The budget for campaigning, advocacy and institutional strengthening to enable implementation was determined to be 10% of the total budget. The proposed framework is not only suitable for Indonesia, but could also be applied to any developing country that aims to increase access to wastewater and solid waste facilities.

Unmasking health determinants and health outcomes for urban First Nations using respondent-driven sampling.

OBJECTIVE: Population-based health information on urban Aboriginal populations in Canada is limited due to challenges with the identification of Aboriginal persons in existing health data sets. The main objective of the Our Health Counts (OHC) project was to work in partnership with Aboriginal stakeholders to generate a culturally relevant, representative baseline health data set for three urban Aboriginal communities in Ontario, Canada. DESIGN: Respondent-driven sampling (RDS). SETTING: Hamilton, Ontario, Canada. PARTICIPANTS: The OHC study, in partnership with the De dwa da dehs ney >s Aboriginal Health Access Centre (DAHC), recruited 554 First Nations adults living in Hamilton using RDS. RESULTS: Among First Nations adults living in Hamilton, 78% earned less than $20 000 per year and 70% lived in the lowest income quartile neighbourhoods. Mobility and crowded living conditions were also highly prevalent. Common chronic diseases included arthritis, hypertension, diabetes and chronic obstructive pulmonary disease and rates of emergency room access were elevated. CONCLUSIONS: RDS is an effective sampling method in urban Aboriginal contexts as it builds on existing social networks and successfully identified a population-based cohort. The findings illustrate striking disparities in health determinants and health outcomes between urban First Nations individuals and the general population which have important implications for health services delivery, programming and policy development.

Genetic dissection of scent metabolic profiles in diploid rose populations.

The scent of flowers is a very important trait in ornamental roses in terms of both quantity and quality. In cut roses, scented varieties are a rare exception. Although metabolic profiling has identified more than 500 scent volatiles from rose flowers so far, nothing is known about the inheritance of scent in roses. Therefore, we analysed scent volatiles and molecular markers in diploid segregating populations. We resolved the patterns of inheritance of three volatiles (nerol, neryl acetate and geranyl acetate) into single Mendelian traits, and we mapped these as single or oligogenic traits in the rose genome. Three other volatiles (geraniol, beta-citronellol and 2-phenylethanol) displayed quantitative variation in the progeny, and we mapped a total of six QTLs influencing the amounts of these volatiles onto the rose marker map. Because we included known scent related genes and newly generated ESTs for scent volatiles as markers, we were able to link scent related QTLs with putative candidate genes. Our results serve as a starting point for both more detailed analyses of complex scent biosynthetic pathways and the development of markers for marker-assisted breeding of scented rose varieties.

The influence of supply and sewerage area characteristics on water and sewerage companies responses to the Water Framework Directive.

Using the example of raw water quality this paper examines the relationship between different spatial characteristics (geographical and physical properties) of Water and Sewerage Companies (WaSCs) supply and sewage areas and response to the Water Framework Directive. Results were obtained from thematic analysis and content analysis of 14 interviews with WaSCs representatives. Principal component analysis and cluster analysis of 51 WaSCs business function characteristics was employed to derive groups of similar WaSCs. Results indicate that there is difference in how WaSCs approach raw water quality issues. It appears that small WaSCs with relatively large agricultural areas in their supply catchments are more likely to seek managerial solutions to raw water quality problems.

Effect of absorbable topical hemostatic agents on the relaxation time of blood: an in vitro study with implications for postoperative magnetic resonance imaging.

OBJECT: Absorbable topical hemostatic agents are commonly used in neurosurgery. In this study the authors examine the longitudinal relaxation time (T1) of blood in contact with these agents over time, measured in vitro, to determine if their presence could affect the interpretation of postoperative magnetic resonance (MR) images. METHODS: Coagulated and anticoagulated blood were used, both oxygenated and deoxygenated. The effects of a collagen-based agent (Collastat) and a cellulose-based agent (Surgicel) on the pH and T1 values of blood and on those of saline (used as a control) were investigated. The T1 was measured as a function of magnetic field strength and time by using a field-cycling relaxometer. This instrument measures 1/T1, the rate of T1, from which the T, value is computed. The T1 values of blood were compared with those of hemostat-induced blood clots and with those of both gray and white matter of the brain. Signal changes on T1-weighted MR images were predicted on the basis of altered T, values in vitro. Postoperative images were visually examined for the predicted changes. With the addition of Surgicel, blood had decreased pH and significantly shortened T1 at all fields, essentially within minutes, although it affected the T1 of saline only minimally. The effect of Surgicel increasingly shortened the T1 for 4 days in oxygenated blood. Collastat had no significant effect. The presence of some paramagnetic methemoglobin in Surgicel-induced clots was demonstrated using the relaxometer at a time when diamagnetic oxyhemoglobin would be present in naturally occurring blood clots. A bright signal that could mimic residual tumor on contrast-enhanced images was predicted and confirmed on postoperative T1-weighted MR images obtained in patients in whom Surgicel lined the tumor bed. It was not present in cases in which Surgicel was not used. CONCLUSIONS: Surgicel alters the appearance of early postoperative MR images. To avoid misinterpretation, clinicians should be aware of this phenomenon.

The effect of standard care, ibuprofen, and music on pain relief and patient satisfaction in adults with musculoskeletal trauma.

OBJECTIVE: The purposes of this study were to determine the most effective nursing intervention to decrease pain for patients with minor musculoskeletal trauma and moderate pain at triage and to examine patient satisfaction. METHODS: Patients were assigned to 1 of 3 intervention groups: (1) standard care (ice, elevation, and immobilization); (2) standard care and ibuprofen; or (3) standard care and music distraction. Patients were monitored for pain ratings for 60 minutes. Patients who sustained minor musculoskeletal trauma within the past 24 hours and presented with pain ratings of 4 or greater were included. Two patient satisfaction questions were asked upon discharge from the emergency department. RESULTS: Seventy-seven patients met the inclusion criteria. No differences in pain ratings between groups were demonstrated. A statistically significant reduction in pain for all patients occurred at 30 minutes (F = 16.18, P <.01) and was maintained at 60 minutes. However, 70% of patients continued to report pain ratings of 4 or greater (on a scale of 1 to 10) at 60 minutes. The reduction in pain was not found to be clinically significant.Eighty-four percent of patients stated that they were more satisfied with their overall care in the emergency department because of the immediate attention to pain relief they received at triage. No differences in satisfaction existed between treatment groups, although patients who reported higher pain ratings expressed statistically significant lower satisfaction with pain management scores (F = 9.375, P =.003). CONCLUSION: None of the therapies-standard care (ice, elevation, immobilization), standard care with ibuprofen, or standard care with music distraction-provided clinically significant pain relief to patients who had minor musculoskeletal trauma (ie, sprains and fractures) and moderate pain at triage. Interestingly, satisfaction scores were sometimes positive, even when pain was not relieved.

Photometric method for the quantification of chlorophylls and their derivatives in complex mixtures: fitting with Gauss-peak spectra.

Accurate quantification of pigments in mixtures is essential in all cases in which separation of pigments by chromatography is impracticable for one reason or another. An example is the analysis of in vivo formation of heavy metal-substituted chlorophylls in heavy metal-stressed plants. We describe here a novel, accurate UV/VIS spectrophotometric method for the quantification of individual chlorophyll derivatives in complex mixtures, which has the potential for universal applicability for mixtures difficult to separate. The method is based on the description of each pigment spectrum by a series of Gaussian peaks. A sample spectrum is then fitted by a linear combination of these "Gauss-peak spectra" including an automatic correction of wavelength inaccuracy and baseline instability of the spectrometer as well as a correction of the widening of absorbance peaks in more concentrated pigment solutions. The automatic correction of peak shifts can also partially correct shifts caused by processes like allomerization. In this paper, we present the Gauss-peak spectra for Mg-chlorophyll a, b, c, pheophytin a, b, c, Cu-chlorophyll a, b, c, and Zn-chlorophyll a in acetone; Mg-chlorophyll a, b, pheophytin a, b, Cu-chlorophyll a, b, allomerized Cu-chlorophyll a, b, and Zn-chlorophyll a, b in cyclohexane; Mg-chlorophyll a, b, pheophytin a, b, and Cu-chlorophyll a, b in diethyl ether.

NC100150 Injection, a preparation of optimized iron oxide nanoparticles for positive-contrast MR angiography.

A preparation of monocrystalline iron oxide nanoparticles with an oxidized starch coating, currently in clinical trials (NC100150 Injection; CLARISCAN), was characterized by magnetization measurements, relaxometry, and photon correlation spectroscopy. By combining the results with a measure of iron content, one can obtain the size and magnetic attributes of the iron cores, including the relevant correlation times for outer sphere relaxation (tau(SO) and tau(D)), and information about the interaction of the organic coating with both core and solvent. The results are 6.43 nm for the iron oxide core diameter, a magnetic moment of 4.38x10(-17) erg/G, and a water-penetrable coating region of oxidized oligomeric starch fragments and entrained water molecules. The latter extends the hydrodynamic diameter to 11.9 nm and lowers the average diffusivity of solvent about 64% (which increases tau(D) accordingly). The nanoparticles show little size-polydispersity, evidenced by the lowest value of r(2)/r(1) at 20 MHz reported to date, an asset for magnetic resonance angiography.

'NC100150', a preparation of iron oxide nanoparticles ideal for positive-contrast MR angiography.

A laboratory-scale synthesis of NC100150 (iron oxide particles with an oxidized starch coating) was characterized by magnetization measurements (vibrating sample magnetometry, VSM), relaxometry (1/T1 NMRD profiles and 1/T2 at 10 and 20 MHz), and dynamic light scattering (photon correlation spectroscopy, PCS). The results were related to give a self-consistent physical description of the particles: a water-impenetrable part making up 12% of the total particle volume, 82% of this volume consisting of an iron oxide core and the remaining 18% consisting of an oxidized starch rind; and, a water-penetrable part making up 88% of the total particle volume, consisting of oxidized starch polymers and entrained water molecules. Relating the magnetization to the relaxometry results required that the oxidized starch coating slows the diffusivity of solvent water molecules in the vicinity of the iron oxide cores. The effect of the organic coating on water diffusivity, not previously considered in the application of relaxation theory to iron oxide nanoparticles, is supported by the much greater (factor of about 2) diameter obtained from the dynamic light scattering measurements in comparison to that obtained from the magnetization measurements. The present work shows that three physical techniques--VSM, relaxometry, and PCS--are needed for properly assessing iron oxide nanoparticles for use as contrast agents for magnetic resonance angiography (MRA). It is also shown that NC100150 has a narrow range of diameters and the smallest value of r2/r1 reported to date, an asset for MRA.

NMRD assessment of Gd-DTPA-bis(methoxyethylamide), (Gd-DTPA-BMEA), a nonionic MRI agent.

RATIONALE AND OBJECTIVES: Gd-DTPA-BMEA, a nonionic bis(methoxyethylamide) derivative of Gd-DTPA, is the active ingredient of OptiMARK, now awaiting FDA approval. In this study, we compare the relaxivities of Gd-DTPA-BMEA (OptiMARK) with those of the commercially available DTPA-based agents Gd-DTPA2- (Magnevist) and Gd-DTPA-BMA (Omniscan) at different field strengths (1/T1 nuclear magnetic relaxation dispersion (NMRD) profiles). In addition, we study how changes in structural attributes of small paramagnetic chelate complexes of Gd3+ ions influence 1/T1 NMRD profiles. METHODS: 1/T1 NMRD profiles of Gd-DTPA-BMEA (OptiMARK) were measured at 5 degrees and 35 degrees C and a set of values for the parameters that describe relaxation by Gd(3+)-proton magnetic dipolar interactions was obtained. The rotational (tau R) and the diffusional (tau D) correlation times for Gd-DTPA-BMA were adjusted for the 15% greater molecular weight of Gd-DTPA-BMEA. tau M (the resident lifetime of Gd(3+)-bound water) was obtained from available 17O NMR relaxation data. For tau S0 and tau V (the low-field relaxation time of the Gd3+ moment and its correlation time), Gd-DTPA-BMA values were taken as initial values and tau S0 refined as needed. RESULTS: Although, at 35 degrees C, tau M is comparable for the two neutral agents and an order of magnitude longer than that for Gd-DTPA2-, the 1/T1 NMRD profiles of Gd-DTPA-BMEA are indistinguishable from those of Gd-DTPA2- and Gd-DTPA-BMA. A 40% increase in the value of tau S0 from Gd-DTPA2- is required for agreement of data and theory for Gd-DTPA-BMEA. CONCLUSIONS: Based on their 1/T1 NMRD profiles, the efficacy of the three agents should be identical in typical clinical MRI applications. The data can be fit reliably to theory, and differences in the fit parameters (and structure) have no effect on the three profiles at 35 degrees C. The relatively long values of tau M for the two neutral agents would only be of importance at low temperatures.

NMRD investigation of DyDTPA- and GdDTPA-labeled starch particles. Selection of a suitable suspension medium and influence of the starch matrix on relaxivity.

RATIONALE AND OBJECTIVES: The primary aim was to investigate the influence of the starch matrix on the T1 relaxivities of starch particles labeled with gadolinium and dysprosium diethylenetriamine pentaacetic acid (GdDTPA-SP and DyDTPA-SP). Achieving this required the selection of a medium that was suitable for suspending the particles and that had field-independent T1 relaxation rates, thereby eliminating errors in relaxivity determinations resulting from a field-dependent background. METHODS: GdDTPA-SP with low and high gadolinium content, DyDTPA-SP, and empty DTPA-SP were suspended in an aqueous medium containing 5% (w/w) of a polyethylene glycol-based block copolymer. 1/T1 NMRD profiles were obtained in the temperature range of 5 degrees to 35 degrees C. RESULTS: Using the block copolymer, particles did not settle, and samples could be prepared at a low temperature to avoid particle degradation, the intrinsic T1 relaxation rate of the suspension medium was field-independent and identical to that of water from 25 degrees to 35 degrees C. The T1 relaxivities of DyDTPA-SP were higher than those of dysprosium diethylenetriamine pentaacetate-bis(methylamide) (DyDTPA-BMA) and decreased with increasing magnetic field strength. The T1 relaxivity of GdDTPA-SP was higher than that of GdDTPA at all fields, and decreased with decreasing temperature and increasing gadolinium content. CONCLUSIONS: The GdDTPA-SP results showed that the particulate starch matrix served a dual role, with opposing influences on relaxivity. It provided a means for increasing the rotational correlation time (tau R), which resulted in higher relaxivities. However, it also retarded radial diffusion of water molecules within the particle interior, which significantly counteracted the enhancing effect of tau R. For DyDTPA-SP, the starch matrix provided an additional diamagnetic contribution, resulting in relaxivities higher than those of DyDTPA-BMA. The block copolymer was suitable as a suspension medium for DyDTPA-SP and GdDTPA-SP and should also be applicable for other particulates.

Secretory and nonsecretory pituitary adenomas are distinguishable by 1/T1 magnetic relaxation rates at very low magnetic fields in vitro.

RATIONALE AND OBJECTIVES: The authors investigated whether hormonally active and inactive pituitary adenomas can be discriminated in vitro by magnetic resonance (MR) imaging-related data. METHODS: 1/T1 nuclear magnetic relaxation dispersion profiles were measured for 39 fresh surgical specimens of secreting and nonsecreting adenomas, classified using clinical criteria or preoperative serum hormone levels. Nonsecreting adenomas were subdivided into hormone-producing and nonhormone-producing by immunostains. At five fields (0.00024 to 1.2 tesla [T]), mean 1/T1 was analyzed for statistically significant differences among these three tumor categories. RESULTS: Mean 1/T1 was significantly higher (P < 0.02) for hormone-secreting than for nonsecreting adenomas at fields below 0.24 T; no significant difference existed at typical MR imaging fields (0.5 to 1.5 T). Mean 1/T1 for hormone-producing and nonhormone-producing, nonsecreting adenomas were not significantly different at any field. CONCLUSIONS: Because 1/T1 at low fields is related to 1/T2 at imaging fields, it may be possible to detect hormone secretion of pituitary adenomas noninvasively by MR imaging.

[Cervical factor in sterility: treatment with intravaginal estriol]. / Fattore cervicale di sterilità: trattamento con estriolo intravaginale.

BACKGROUND: The aim of our study was to evaluate the efficacy and tolerability of vaginal estriol in treating the isolated cervical factor. METHODS: Three different groups of patients were selected at random on the basis of the administered therapy (estriol, ethinyl-estradiol, bromhexine associated with gonadotropins). The patients (thirty in all) came to the Autonomous Sterility Department of the Niguarda Ca' Granda Hospital in Milan during the November 1994-January 1996 period. The following parameters were evaluated: cervical score according to Insler, cervical pH; in vivo penetration test (PCT) at third and sixth cycle of treatment; evaluation of the hormonal profile during the ovulatory period of estriol, estradiol, LH and progesterone at the third and sixth cycles of treatment; any possible pregnancy. RESULTS: On the whole, 23 patients out of 30 (76.6%) had a positive in vivo penetration test. Particularly, a more favourable result was observed in the group to which vaginal estriol was administered as it presented, at treatment end, a positive PCT in 90% of cases. Moreover, always in the latter group, a greater percentage of pregnancies (40%) was observed. CONCLUSIONS: The obtained results have demonstrated that the drug we have studied can be recommended as a valid therapy for the treatment of the isolated cervical factor of sterility.

Relaxation of solvent protons by solute Gd3+-chelates revisited.

The magnetic field dependence (NMRD profile) of 1/T1 of solvent protons in an aqueous solution of Gd(DTPA)2- was remeasured at 5, 15, 25, 30, and 35 degrees C. The data were reanalyzed with the usual low-field theory, using recently published values for tauM, the residence lifetime of the single inner-coordinated waters of solute Gd(DTPA)2-. (These tauM values are significantly longer than earlier estimates). Values were obtained for three dynamic parameters: tauR, the rotational relaxation time of solute ions, and tauSo and tauV, the low-field relaxation time of the Gd3+ magnetic moment and the related correlation time. These Gd(DTPA)2- values, together with recent results for tauM for Gd(DTPA-BMA)--a nonionic structural analog of Gd(DTPA)2- with an unusually long tauM--were used to calculate NMRD profiles at 5 and 35 degrees C. These profiles agree very well with new data given here for a solution of Gd(DTPA-BMA). This reaffirms the importance of knowing the temperature-dependent values of tauM a priori in order to obtain unambiguous quantitative theoretical analyses of NMRD profiles of chelates of known structure. Additionally, the theory of inner sphere relaxation is extended to high fields, at which the magnetic energy of a solute moment is greater than its thermal energy.

Calcification can shorten T2, but not T1, at magnetic resonance imaging fields. Results of a relaxometry study of calcified human meningiomas.

RATIONALE AND OBJECTIVES: Water content and water-proton relaxation rates are reported for fresh, histologically characterized, surgical specimens of calcified human intracranial meningiomas and compared with results for noncalcified meningiomas from an earlier study and with calcium hydroxyapatite (CaHA) suspensions to elucidate the influence of calcification on magnetic resonance imaging (MRI) signal intensity of calcified meningiomas. METHODS: The magnetic field dependence of 1/T1 of water protons (nuclear magnetic relaxation dispersion profile) and dry weights are reported for 38 calcified nonhemorrhagic and 3 hemorrhagic specimens of known histologic subtype, a subset of the 67 specimens measured earlier. Calcification was considered mild or heavy when the dry weight was within or above the range for noncalcified meningiomas. Preliminary 1/T1 profiles for pure CaHA and a single high-field 1/T2 value also are reported. RESULTS: The ranges of dry weights and of low-field 1/T1 values were twice as large for calcified as for noncalcified meningiomas. No correlation was found between low-field 1/T1 and either histologic subtype or dry weight. Mild calcification produced the highest low-field 1/T1 values; the most heavily calcified tumor had slightly increased low-field 1/T1. Calcium hydroxyapatite increases low-field 1/T1 significantly but not high-field 1/T1; high-field 1/T2 is large. For calcified hemorrhagic meningiomas, increases in both low-field and high-field 1/T1 were seen. CONCLUSION: For mild calcification, MRI signal voids result from an increased high-field 1/T2; for heavier calcification, reduced proton density (from excluded water) becomes of increasing importance. Cellular CaHA appears to brighten the signal in T1-weighted MRI in the presence of hemorrhage.

Correlation of relaxometry and histopathology: the transplantable human glioblastoma SF295 grown in athymic nude mice.

Human glioblastomas of the brain are characterized by a wide range of proton relaxation rates in vitro (1/T1 and 1/T2) and heterogeneous appearance in magnetic resonance imaging. It was previously found that their 1/T1 values vary widely at magnetic field strengths much below imaging fields, even at the same water content. In the present study, we measure 1/T1 at different magnetic field strengths (NMRD profile) for a specific transplantable, human glioblastoma (SF295), grown subcutaneously in athymic nude mice, to search for histologic characteristics that might correlate with the variability of 1/T1 at low fields (1/T1L). Using a field-cycling relaxometer, NMRD profiles were obtained for 32 fresh, histologically characterized, tumor specimens, 7 to 24 days post implantation of cryopreserved SF295 fragments. Tumor volume, dry weight, and pH of specimens were determined, the extent of hemorrhage and necrosis rated, and specimen location within the tumor recorded. A statistically significant increase in the average 1/T1 was found with increasing level of necrosis at 0.0024 T and below, possibly reflecting progressive protein aggregation in samples with up to 40% necrosis. This correlation was not significant at imaging fields. Although pH was increased in central necrosis, neither pH, dry weight, sample location, nor fresh hemorrhage could explain the changes in 1/T1L. The variability of 1/T1L among SF295 samples is much reduced compared to that of fresh surgical specimens of human glioblastomas of the brain. The heterogeneous appearance of glioblastomas in MRI may have a histologic correlate which reflects molecular changes involved with induction of cell death and necrosis. Further investigations may identify the factors responsible for affecting 1/T1L (hypoxia, radiation, chemotherapy).

Relaxometry of noncalcified human meningiomas. Correlation with histology and solids content.

RATIONALE AND OBJECTIVES: Resected meningiomas were examined by relaxometry and light microscopy to evaluate the potential of magnetic resonance imaging (MRI) for identifying histologic subtypes and for discriminating among benign, radiation therapy-induced, and malignant meningiomas. METHODS: The magnetic field dependence of 1/T1 of water protons (nuclear magnetic relaxation dispersion [NMRD] profile) and the water content (dry weight) were measured for 67 specimens, and the data were compared with histology. Only noncalcified, nonhemorrhagic meningiomas are reported. RESULTS: No correlations were found between NMRD profiles, dry weight, and any histologic subtype, in contrast to an analogous study of astrocytomas. Rather, meningiomas have a broader variability of dry weight and 1/T1 than related parenchyma but a much narrower range than all grades of astrocytomas. The mean value of 1/T1, at all fields, is slightly higher in meningiomas--and the mean water content about the same--as adult cortical gray matter. CONCLUSION: Meningiomas are frequently isointense with cortex, and histologic subtypes cannot be differentiated at any magnetic field strength by MRI using only T1- or proton density-weighted MRI.