Multi-level Assessment Cerebrospinal Fluid Flow in Patients with Chiari I Malformation

The purpose of this study is to characterize the cerebrospinal fluid (CSF) flow throughout the cardiac cycle in the conditions of Chiari I at intracranial and cervical levels. Magnetic resonance imaging studies were examined with phase-contrast magnetic resonance imaging retrospectively cardiac triggered (Quantitative Flow technique). 60 healthy volunteers (control group) and 12 patients with the anomaly of Chiari I (patient’s group) were investigated. Mean velocity, mean flux and peak velocity values of CSF flow at the five levels (the Sylvian aqueduct, the fourth ventricle, the Magendie’s foramen, subarachnoid space of the foramen occipital magnum and the cervical level) were defined. Analysis of differences between respective mean values of CSF flow has shown that CSF flow characteristics have the highest values in the Sylvian aqueduct and on the cervical level in both groups. Our findings show that mean velocity and mean flux of antegrade (from head to feet) flow have significantly higher values in comparison with the retrograde flow (from feet to head) through investigated structures, respectively (p < 0.01). Our findings show the importance of multi-level cerebrospinal fluid flow assessment and allow investigating this system as a single whole, with their relationships and interaction laws.     

Region-Specific Susceptibilities to Cuprizone-Induced Demyelination of C57BL/6 Mouse: In vivo T2WI and DTI Studies at 7.0T

The cuprizone (CPZ) mouse model of demyelination was recognized and used to explore multiple sclerosis (MS)-like brain lesions. In this study, we assessed CPZ-treated mice using T₂-weighted imaging and diffusion tensor imaging (DTI). C57BL/6 mice treated with 2 weeks of 0.2 % CPZ-containing diet (n = 10) and regular chow diet (n = 10) were scanned with a 7.0 T MRI scanner (Agilent, USA), respectively, using fast spin-echo and fast spin-echo DTI sequences. The normalized T₂ signal intensity (normalized to the cerebrospinal fluid) was calculated and fractional anisotropy (FA value), mean diffusivity, axial diffusivity and radial diffusivity were measured in the brain region of the cerebral cortex (CTX), caudate putamen (CP), hippocampus (HP) and thalamus (TH). Compared with controls, increased normalized T₂ signal intensities and reduced FA values (p < 0.05) were observed in the CTX, HP and CP (p < 0.01), but not in TH in cuprizone-fed mice. In the regions of reduced FA values, an increase in mean diffusivity (p < 0.05) and radial diffusivity (p < 0.05) was also found. Significant decreased axial diffusivity was only observed in CTX (p < 0.05). DTI is sensitive to detecting cuprizone-induced demyelination of C57BL/6 mice. This study suggests that CTX, HP and CP are more susceptible to cuprizone-induced demyelination than TH. Our results also indicate that the decrease of FA value may be more likely due to increased radial diffusivity.     

Temporal and spatial assessment of normal cerebrospinal fluid dynamics with MR imaging

The purpose of this study was to measure normal cerebrospinal fluid (CSF) pulsations within the intracranial and upper cervical subarachnoid spaces and the ventricular system. Phase contrast cine MR sequences were performed in sagittal and axial planes on 13 volunteers with flow encoding in the craniocaudal direction. CSF pulsations displayed considerable variations in healthy subjects, depending both on measurements localization and subjects, with CSF peak velocities ranging from 0 to 7 cm/s. In the subarachnoid spaces, the highest velocities occurred in the anterior location and increased from the cerebellar pontine angle cisterns towards the lower cervical spaces. In the ventricular system, the highest velocities occurred through the aqueduct of Sylvius. CSF flow within the third ventricle seemed to reflect a circular motion. There was a caudal net CSF flow in the aqueduct whereas in the upper cervical spaces net CSF flow was caudal anteriorly and cranial laterally. Velocity profiles of CSF pulsations demonstrated arterial morphology. After the R wave, caudal systolic motion was first observed in the posterior subarachnoid spaces, soon after in the anterior subarachnoid spaces and later in the ventricular system. Considering the morphology of CSF pathways, three successively initiated phenomena may explain the temporal course of CSF motion: the systolic expansion of the main arteries at the base of the brain, the systolic expansion of the cerebrospinal axis and, finally, the systolic expansion of the choroid plexuses.     

Quantification of low-velocity motion using a navigator-echo supported MR velocity-mapping technique: Application to intracranial dynamics in volunteers and patients with brain tumours

Gradient-echo pulse sequences with velocity-encoding gradients of 22.5–25 mT/m, were used for brainmotion and CSF-flow studies. To reduce motion artifacts, a phase-correction technique based on navigator echoes was evaluated. Three patients with right-sided parietal tumours were investigated; one astrocytoma grade III–IV, one astrocytoma grade I–II and one benign meningioma. In healthy volunteers, a maximal brain-tissue velocity of (0.94 ± 0.26) mm/s (mean ± 1SD) was observed, which is consistent with previously presented results. The phase correction was proven useful for reduction of artifacts due to external head movements in modulus and phase images, without loss of phase information related to internal motion. The tissue velocity within the astrocytomas was low during the entire cardiac cycle. An abnormally high rostral velocity component was, however, observed in the brain tissue frontal to the astrocytomas. In all patients, an abnormal CSF flow pattern was observed. The study of brain motion may provide further understanding of the effects of tumours and other pathological conditions in the brain. When considering intracranial motion as a source of error in diffusion/perfusion MRI, the present study suggests that a pathology can alter the properties of brain motion and CSF flow considerably, leading to a more complex impact on diffusion/perfusion images.     

Assessment of the biomechanical state of intracranial tissues by dynamic MRI of cerebrospinal fluid pulsations: a phantom study

We used a cranial phantom to investigate how intracranial mechanical factors [brain compliance and the resistance to the flow of cerebrospinal fluid (CSF)] affect the way in which CSF pulsations are driven by pulsatile transcranial blood flow. Dynamic phase-contrast magnetic resonance imaging (MRI) was used to measure the transfer function between vascular pulsations and pulsatile response of the CSF below the foramen magnum of the phantom. We found that the coupling between the high frequency components of cervical CSF flow and transcranial blood flow was decreased when the phantom was modified to simulate increased brain compliance and increased resistance to CSF flow.     

Assessment of the systemic distribution of a bioconjugated anti-Her2 magnetic nanoparticle in a breast cancer model by means of magnetic resonance imaging

The aim of this study was to determine the systemic distribution of magnetic nanoparticles of 100 nm diameter (MNPs) coupled to a specific monoclonal antibody anti-Her2 in an experimental breast cancer (BC) model. The study was performed in two groups of Sprague–Dawley rats: control (n = 6) and BC chemically induced (n = 3). Bioconjugated “anti-Her2-MNPs” were intravenously administered, and magnetic resonance imaging (MRI) monitored its systemic distribution at seven times after administration. Non-heme iron presence associated with the location of the bioconjugated anti-Her2-MNPs in splenic, hepatic, cardiac and tumor tissues was detected by Perl’s Prussian blue (PPB) stain. Optical density measurements were used to semiquantitatively determine the iron presence in tissues on the basis of a grayscale values integration of T1 and T2 MRI sequence images. The results indicated a delayed systemic distribution of MNPs in cancer compared to healthy conditions with a maximum concentration of MNPs in cancer tissue at 24 h post-infusion.     

EADC Values in Diagnosis of Renal Lesions by 3.0 T Diffusion-Weighted Magnetic Resonance Imaging: Compared with the ADC Values

Exponential apparent diffusion coefficient (EADC) is an indicator of diffusion-weighted imaging (DWI) and reflects the pathological changes of tissues quantitatively. However, no study has been investigated in the space-occupying kidney disease using EADC values. This study aims to evaluate the diagnostic role of EADC values at a high magnetic field strength (3.0 T) in kidney neoplastic lesions, compared with that of the ADC values. Ninety patients with suspected renal tumors (including 101 suspected renal lesions) and 20 healthy volunteers were performed MRI scanning. Diffusion-weighted imaging was performed with a single-shot spin-echo echo-planar imaging (SE-EPI) sequence at a diffusion gradient of b = 500 s/mm². We found renal cell carcinoma (RCC) can be distinguished from angiomyolipoma, and clear cell carcinoma can be distinguished from non-clear cell carcinoma by EADC value. There was significant difference in overall EADC values between renal cell carcinoma (0.150 ± 0.059) and angiomyolipoma (0.270 ± 0.108) when b value was 500 s/mm². When receiver operating characteristic (ROC) was higher than 0.192, the sensitivity and specificity of EADC value of renal cell carcinoma were 84.6 and 81.1 %, respectively. In conclusion, EADC map shows the internal structure of the kidney tumor more intuitively than the ADC map dose, and is also in line with the observation habits of the clinicians. EADC can be used as an effective imaging method for tumor diagnosis.     

In vivo longitudinal Myelin Water Imaging in rat spinal cord following dorsal column transection injury

Longitudinal Myelin Water Imaging was carried out in vivo to characterize white matter damage following dorsal column transection (DC Tx) injury at the lumbar level L1 of rat spinal cords. A transmit–receive implantable coil system was used to acquire multiple spin-echo (MSE) quantitative T2 data from the lumbar spinal cords of 16 rats at one week pre-injury as well as 3 and 8 weeks post-injury (117 microns in-plane resolution and 1.5 mm slice thickness). In addition, ex vivo MSE and DTI data were acquired from cords fixed and excised at 3 or 8 weeks post injury using a solenoid coil. The MSE data were used to generate Myelin Water Fractions (MWFs) as a surrogate measure of myelin content, while DTI data were acquired to study damage to the axons. Myelin damage was assessed histologically with Eriochrome cyanine (EC) and Myelin Basic Protein in degenerated myelin (dgen-MBP) staining, and axonal damage was assessed by neurofilament-H in combination with neuron specific beta-III-tubulin (NF/Tub) staining. These MRI and histological measures of injury were studied in the dorsal column at 5 mm cranial and 5 mm caudal to injury epicenter. MWF increased significantly at 3 weeks post-injury at both the cranial and caudal sites, relative to baseline. The values on the cranial side of injury returned to baseline at 8 weeks post-injury but remained elevated on the caudal side. This trend was found in both in vivo and ex vivo data. This MWF increase was likely due to the presence of myelin debris, which were cleared by 8 weeks on the cranial, but not the caudal, side. Both EC and dgen-MBP stains displayed similar trends. MWF showed significant correlation with EC staining (R = 0.63, p = 0.005 in vivo and R = 0.74, p = 0.0001 ex vivo). MWF also correlated strongly with the dgen-MBP stain, but only on the cranial side (R = 0.64, p = 0.05 in vivo; R = 0.63, p = 0.038 ex vivo). This study demonstrates that longitudinal MWI in vivo can accurately characterize white matter damage in DC Tx model of injury in the rat spinal cord.     

Effects of Sleep Deprivation on the Sedation of Pediatric Patients Undergoing MRI Examinations

Sedation is an essential factor for pediatric magnetic resonance imaging (MRI) procedure. A long-term failure of sedation has a detrimental effect on a 1 day test plan. Given this background, this study examined the effects of sedation using a sleep deprivation method in pediatric patients scheduled to undergo an MRI examination. The current study examined 54 patients (36 boys and 18 girls) with diseases, such as epilepsy, brain tumor, development delay, mental retardation, and cerebral infarction, who were treated at our medical institution from December 2009 to March 2010. The patients were classified into two groups: group A (n = 27) with sleep deprivation, and group B (n = 27) without sleep deprivation. The mean age of these patients was 4.2 years. Comparative analysis of groups A and B was performed to assess the success rate of pediatric sedation, the time elapsed until complete sedation had been achieved, and the frequency at which patients took Pocral syrup (chloral hydrate). In group A, patients were allowed to start sleep 1 hr later and were woken 1 hr earlier than their mean sleep time. According to this pretreatment, the rate of successful sedation, frequency of the administration of Pocral syrup, and the time elapsed until deep sedation had been achieved were measured. In group A, the rate of successful sedation was 100%, the mean time elapsed until deep sedation had been achieved was 23 min, and the mean frequency of Pocral syrup administration was 1.2 times. In addition, the proportions of patients who had achieved successful sedation after one-time use and two-time use of Pocral syrup were 77.8% and 22.2%, respectively. In group B, successful sedation was achieved in 89%, and the mean time elapsed until deep sedation was 39 min. The mean frequency of Pocral syrup administration was 1.5 times. The proportions of patients who had achieved successful sedation after one-time use and two-time use of Pocral syrup were 51.9% and 48.12%, respectively. The statistical significance was tested using a nonparametric analysis, Mann–Whitney U Test (p < 0.05). Other studies have reported that sleep deprivation had no significant effects. An actual comparison of the sleep-deprived and other patients showed that sleep deprivation affected the rate of successful sedation, the frequency of Pocral syrup administration, and the time elapsed until the patients were sedated. The rate of successful sedation was significantly higher in group A than in group B. The time elapsed until deep sedation had been achieved was also significantly shorter in group A than in group B. In addition, the frequency of Pocral syrup administration (administration dose) was significantly lower in group A than in group B. In conclusion, sleep deprivation increases the effectiveness of pediatric sedation in an MRI examination of pediatric patients and might assist in performing an MRI examination more efficiently in pediatric patients.     

Simultaneous CO concentration and temperature measurements using tunable diode laser absorption spectroscopy near 2.3 μm

Simultaneous measurements of carbon monoxide (CO) mole fraction and temperature using tunable diode laser absorption spectroscopy (TDLAS) near 2.3 μm are reported. The measurement method uses ro-vibrational transitions [R(27): v″ = 1 → v′ = 3] and [R(6): v″ = 0 → v′ = 2] in the first overtone band of CO near 2.3 μm (~4,278 cm^?1). The measurements were performed in the post flame environment of fuel rich premixed ethylene–air flames with a N₂ co-flow, stabilized over a water cooled McKenna burner. Non-uniformity in the temperature and CO mole fraction, along the absorption line of sight, in the mixing layer of the co-flow, was considered during data analysis. The TDLAS based temperature measurements (±80 K) were in good agreement with those obtained using N₂ vibrational coherent anti-Stokes Raman scattering (±20 K), and the CO mole fraction measurements were in good agreement with the equilibrium values, for equivalence ratios lower than 1.8. A signal to noise ratio of 45 was achieved at an equivalence ratio of 1 for a CO concentration of 0.8 % at 1,854 K.     

Flow and Heat Transfer Characteristics of in-Line Impinging Jets With Cross-Flow At Short Jet-To-Plate Distance

The aim of this research is to numerically and experimentally study the flow and heat transfer characteristics of in-line impinging jets in cross-flow. The jets from a row of round orifices are perpendicularly impinged on the inner surface of a rectangular wind tunnel at a short distance between the orifice plate and impinged surface (H) of 2D, where D is a diameter of the orifice. The jet velocity was fixed corresponding to Re = 13,400 for all experiments, and the cross-flow velocity was varied at three different velocity ratios (velocity ratio, jet velocity/cross-flow velocity) of 3, 5, and 7. The heat transfer characteristic was visualized using a thermochromic liquid crystal sheet, and the Nusselt number distribution was evaluated by an image processing technique. The flow pattern on the impinged surface was also visualized by an oil film technique. The numerical simulation was used to explore a flow interaction between the impinging jets and cross-flow. The results indicated that Nusselt number peak increased by the increasing cross-flow velocity for short jet-to-plate distance. For the range determined, the maximum local Nusselt number peak was obtained at VR = 3 as the consequence of high velocity and high turbulence kinetic energy of jet impingement.     

Experimental Investigation of Subcooled Vertical Upward Flow Boiling in a Narrow Rectangular Channel

Accurate models for the onset of nucleate boiling, density of active nucleation sites (N_a), bubble departure size (D_d), and departure frequency (f_d) are essential to the success of computational fluid dynamics analysis of two-phase thermal-hydraulics involving subcooled flow boiling in nuclear reactor systems. This work presents an experimental study of subcooled flow boiling in a vertical upward narrow rectangular channel that mimics the flow passage in the plate fuel assembly of boiling water reactors. The experiments are conducted over a range of mass flux (G = 122–657 kg/m²s), inlet subcooling (ΔT_sub = 4.7–33.3?C), and heat flux (q″ = 1.7–28.9 W/cm²). Based on the experimental data, empirical correlations are developed for the prediction of onset of nucleate boiling, N_a, D_d, and f_d for given flow conditions. These correlations are valid in the nucleate boiling regime when the wall superheat is less than 12°C and can be incorporated in the computational fluid dynamics codes to enable more precise simulation of subcooled flow boiling heat transfer and two-phase flow in nuclear energy applications.     

Anatomical brain MRI study of pediatric cancer survivors treated with chemotherapy: Correlation with behavioral measures

The negative impacts of chemotherapy on pediatric patients treated with chemotherapy during the formative years of brain development are understudied compared to adult chemotherapy cancer patients. This work investigated the morphometry, cortical thickness, and subcortical volumes using MRI and their correlations with behavioral measures in pediatric oncology survivors treated with chemotherapy. Chemotherapy-treated childhood cancer survivors (N = 15, 15.12 ± 5.98 years old) diagnosed with a non-central nervous system malignancy and healthy age-matched controls (N = 15, 15.13 ± 4.21 years old) were studied. MRI was acquired at 3 Tesla. Behavioral Rating Inventory of Executive Functioning (BRIEF) Parental Rating, Purdue Pegboard manual dexterity and n-back working memory measures were administered. Structural MRI scans at 3 Tesla were acquired. Voxel-based morphometry, cortical thickness and subcortical volumes were analyzed and correlated with behavioral scores. Parametric statistics with a p < .05 and adjusted for multiple comparison corrections were performed. Patients exhibited significantly smaller gray-matter volumes in the left globus pallidum, bilateral thalami, left caudate and left nucleus accumbens (p < .05) and thinner cortex in the right parahippocampal gyrus (p < .05) compared to controls. BRIEF scores were similar to normative values. Purdue Pegboard revealed manual dexterity deficits compared to normative values, and the n-back task showed working-memory deficits in patients compared to controls. Left thalamus volume positively correlated with dexterity performance (p = .029). The number of correct answers positively correlated and the number of incorrect answers negatively correlated with total-brain and white-matter volume (p < .05), but not gray-matter volume (p > .05). Our results support the hypothesis that the neurotoxicity of systemic chemotherapy has widespread negative effects on brain development in pediatric oncology patients with relatively mild cognitive deficits. MRI identified neuroanatomical changes have the potential to provide neural correlates of the sequelae associated with pediatric chemotherapy.     

Optical properties of zinc phthalocyanine thin films prepared by pulsed laser deposition

ZnPc thin films were prepared by pulsed laser deposition (KrF laser, λ = 248 nm, τ = 5 ns, f = 50 Hz) on suprasil substrates in vacuum. Optical properties in UV–Vis spectral region were analyzed as functions of laser fluence from 40 to 100 mJ/cm² by spectrophotometric and spectral ellipsometry measurements. The spectral ellipsometry data were treated using a three-layer model (substrate, film, roughness). The best results of data fitting were obtained when Q band was characterized by two Lorentz oscillators, while two Gaussian oscillators were used for B and C band fitting. We derived the band gap using Tauc plot considering ZnPc a direct band gap semiconductor. The band gap values were found decreasing from 3.13 to 3.09 eV with increasing laser fluence, which might be related with formation of trapping sites at higher fluence.     

EPR, Optical Absorption and Superposition Model Study of Fe3+-Doped Ammonium Dihydrogen Phosphate Single Crystals

X-band electron paramagnetic resonance (EPR) studies are carried out on Fe³⁺ ions doped in ammonium dihydrogen phosphate (ADP) single crystals at room temperature. The crystal field and spin Hamiltonian parameters are evaluated from the resonance lines obtained at different angular rotations. The obtained values of spin Hamiltonian and zero-field parameters of the Fe³⁺ ion in ADP are: g = 1.994 ± 0.002, |D| = (220 ± 5) × 10^?4 cm^?1 and a = (640 ± 5) × 10^?4 cm^?1. On the basis of EPR data, the site symmetry of the Fe³⁺ ion in the crystal is discussed. The Fe³⁺ ion enters the lattice substitutionally replacing the NH₄ ⁺ sites. The optical absorption of the crystal is also studied at room temperature in the wavelength range of 195–925 nm. The energy values of different orbital levels are calculated. The observed bands are assigned as transitions from the ⁶ A _1g (S) ground state to various excited quartet levels of the Fe³⁺ ion in a cubic crystalline field. From the observed band positions, Racah interelectronic repulsion parameters (B and C), cubic crystal field splitting parameter (D _q ) and Trees correction are calculated. There values are: B = 970, C = 1,923, D _q  = 1,380 cm^?1 and α = 90 cm^?1, respectively. On the basis of EPR and optical data, the nature of bonding in the crystal is discussed. The zero-field splitting (ZFS) parameters are also determined theoretically using B _kq parameters estimated from the superposition model. The values of ZFS parameters thus obtained are |D| = (213 ± 5) × 10^?4 cm^?1 and |E| = (21 ± 5) × 10^?4 cm^?1.     

Heat Transfer Characteristics in a Double-Pipe Heat Exchanger Equipped with Coiled Circular Wires

An experimental investigation has been carried out to study the enhancement in heat transfer coefficient by inserting coiled wire around the outer surface of the inner tube of the double-pipe heat exchanger. Insulated wires, with a circular cross-section of 2 mm diameter, forming a coil of different pitches (p = 6, 12, and 20 mm), were used as turbulators. The investigation is performed for turbulent water flow in a double-pipe heat exchanger with cold water in the annulus space for both parallel and counter flows. The experiments were performed for Reynolds numbers ranging from 4,000 to 14,000. The experimental results reveal that the use of coiled circular wires leads to a considerable increase in heat transfer coefficients compared with a smooth wall tube for both parallel and counter water flows. The mean Nusselt number increases with Reynolds number and pitch. The convective heat transfer coefficient for a turbulent water flow increases for all coiled wire pitches, with the highest enhancement of about 450% for counter flow and 400% for the parallel flow. New correlations for mean relative Nusselt numbers at different coiled wire pitches are provided.     

Metastable states of hydrogen: their geometric phases and flux densities

We discuss the geometric phases and flux densities for the metastable states of hydrogen with principal quantum number n = 2 being subjected to adiabatically varying external electric and magnetic fields. Convenient representations of the flux densities as complex integrals are derived. Both, parity conserving (PC) and parity violating (PV) flux densities and phases are identified. General expressions for the flux densities following from rotational invariance are derived. Specific cases of external fields are discussed. In a pure magnetic field the phases are given by the geometry of the path in magnetic field space. But for electric fields in presence of a constant magnetic field and for electric plus magnetic fields the geometric phases carry information on the atomic parameters, in particular, on the PV atomic interaction. We show that for our metastable states also the decay rates can be influenced by the geometric phases and we give a concrete example for this effect. Finally we emphasise that the general relations derived here for geometric phases and flux densities are also valid for other atomic systems having stable or metastable states, for instance, for He with n = 2. Thus, a measurement of geometric phases may give important experimental information on the mass matrix and the electric and magnetic dipole matrices for such systems. This could be used as a check of corresponding theoretical calculations of wave functions and matrix elements.     

Diagnosing Aortic Stenosis Using Phase Contrast MRI: Comparison with Echocardiography Depending on the Image Plane

This study intended to suggest a better method of measuring the precise peak velocity of the bloodstream of a patient suffering from aortic stenosis (AS) with a view to improving the reliability of the magnetic resonance imaging (MRI) scan. The study targeted 23 patients whose direction of the stenotic flow jet was different from that of the blood vessel among the patients who were diagnosed with a moderate or higher level of AS on echocardiography. The phase-contrast (PC) MRI was used for quantitatively measuring the bloodstream velocity. The examination was accomplished according to the two different image plane selection methods in the same patient. After placing the image planes perpendicular to the blood vessel and the stenotic flow jet, respectively, we obtained the two velocity encoded images to calculate the peak blood velocities to compare them with the measurement results from an echocardiography scan. According to the comparison results of the peak blood velocities, echocardiography showed a mean peak blood velocity of 4.19 ± 1.05 m/s. On the PC MRI scan, the peak blood velocity was 3.11 ± 0.77 m/s when the image plane was perpendicular to the blood vessel and 3.58 ± 0.87 m/s when the image plane was placed perpendicular to the stenotic flow jet. As a result, if PC MRI is used to measure the peak blood velocity for patients with AS, then the image plane must be placed perpendicular to the stenotic flow jet, instead of perpendicular to the blood vessel, to provide a more precise value of a low blood velocity.     

Shifts of g Values in the Excited Triplet States of Metal Complexes Studied by Time-Resolved W-band EPR

A highly time-resolved high-frequency/high-field W-band electron paramagnetic resonance (EPR) (ν ~ 94 GHz) is a powerful technique to determine small g anisotropies of transient paramagnetic species. We applied this method to studies of the lowest excited triplet (T₁)³ ππ* states in metal complexes such as a platinum (Pt) diimine complex and metal (Zn and Mg) porphines in rigid glasses. From the analyses of time-resolved EPR spectra, g anisotropies were obtained as g _z  = 2.0048, g _x  = g _y  = 2.0035 for Pt(b-iq)(CN)₂ (b-iq = 3,3′bi-isoquinoline) and g _z  = 1.9968, g _x  = g _y  = 2.0022 for zinc tetraphenylporphine (ZnTPP). No measurable anisotropies were found for magnesium (Mg) TPP. The g values of the Pt complex are larger than g _e (=2.0023, g value of free electron) and that g _z of ZnTPP is smaller than g _e. These results were interpreted in terms of the nature of the perturbed states: the higher triplet ππ′* state mixes with T₁(ππ*) via spin–orbit coupling in ZnTPP. In contrast, the higher triplet dπ* state is involved in this coupling for the Pt complex. Thus, the nature of the perturbed state can be distinguished from the anisotropic g values of the T₁(ππ*) state.