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PubMed2002

Diffusion-weighted echoplanar MR imaging of the salivary glands.

OBJECTIVE: We determined the apparent diffusion coefficients of normal and dysfunctional salivary glands. SUBJECTS AND METHODS: A diffusion-weighted single-shot spin-echo type of echoplanar MR imaging was performed on the parotid or submandibular glands, or both, in 36 healthy subjects, 20 patients with Sjögren's syndrome, and six patients with sialoadenitis. The apparent diffusion coefficient of the salivary gland was calculated using two b factors (b = 500 and 1,000 sec/mm(2)). RESULTS: The apparent diffusion coefficient was lower in the parotid glands (0.28 x 10(-3) mm(2)/sec) than that of the submandibular glands (0.37 x 10(-3) mm(2)/sec). The apparent diffusion coefficient was increased in sialoadenitis, whereas it decreased with abscess formation. The apparent diffusion coefficients of the parotid glands in patients with Sjögren's syndrome correlated with the salivary flow rates but not with the sialographic gradings of the glands. We also found a correlation of the decreases in apparent diffusion coefficients with the severity of gland damage as assessed on T1-weighted MR images. CONCLUSION: Diffusion-weighted echoplanar MR imaging may reveal diseased states of the salivary glands.

Adult↗

PubMed2002

Diffusion of mepivacaine between adjacent synovial structures in the horse. Part 2: tarsus and stifle.

This paper tests the hypothesis that the local analgesic agent mepivacaine diffuses between adjacent equine synovial structures in the hindlimb and with greater frequency than latex, gelatine dye or contrast media. We report the incidence of diffusion of mepivacaine between the tarsometatarsal, centrodistal and tarsocrural joints, and the 3 synovial compartments of the stifle in 33 fresh equine cadavers. The tarsometatarsal joint and one synovial compartment of the stifle in the left limb and the centrodistal joint and a different synovial compartment of the stifle in the right limbs were injected with mepivacaine. Following flexion and extension of the limb, synovial fluid was aspirated from the noninjected centrodistal and tarsometatarsal joints and the tarsocrural joints of the hock and the noninjected compartments of the stifle. Concentrations of mepivacaine in these samples were assayed using an enzyme linked immunosorbent assay. For samples obtained by dilution of synovial fluid the concentration of mepivacaine was determined by comparing the concentration of urea in the diluted synovial fluid and the concentrations of the serum urea. Mepivacaine was detected in 25/25 (100%) adjacent tarsometatarsal and centrodistal joints after diffusion in both directions, in 23/25 (92%) of tarsocrural joints after diffusion from tarsometatarsal joints and in 22/25 (88%) tarsocrural joints after diffusion from centrodistal joints in the hocks. Diffusion from the femoropatellar to medial and lateral femorotibial joints and between the medial and lateral femorotibial joints in both directions were 20/20 (100%). Diffusion from the lateral femorotibial to the femoropatellar joint was 18/20 (90%) and from the medial femorotibial to femoropatellar joints 17/20 (85%). Mepivacaine was detected at concentrations >0.3 mg/l in a proportion of samples ranging from 15/25 (60%) in the tarsocrural joint following tarsometatarsal joint injection to 18/20 (90%) in the lateral femorotibial joint after femoropatellar joint injection. At mepivacaine concentrations >100 mg/l, detection ranged from 3/20 (15%) in the lateral femorotibial joint from the medial femorotibial joint to 19/25 (76%) in the centrodistal joint from the tarsometatarsal joint. At mepivacaine concentrations >300 mg/l, detection ranged from 1/25 (4%) in the tarsocrural joint from the tarsometatarsal joint to 16/25 (64%) in the from centrodistal joint the tarsometatarsal joint. The results show greater diffusion of mepivacaine between these adjacent synovial structures than assumed from previous anatomical, latex injection and contrast arthrographic studies. Therefore, commonly performed intrasynovial local analgesic techniques in the hindlimb of the horse are not as specific as first thought.

Anesthetics, Local↗

PubMed1999

[The clinical efficacy of magnetic resonance with diffusion-weighted sequences in the assessment of acute cerebral ischemia].

PURPOSE: To evaluate the efficacy of diffusion weighted Magnetic Resonance Imaging in the diagnosis of acute ischemic infarction and correlate the signal changes observed in the acute phase with final brain damage. MATERIAL AND METHODS: Fifteen patients (six women and nine men: mean age 68 years) with acute ischemic stroke (within 12 hours) underwent diffusion MRI. All the patients were selected on the basis of sudden focal neurologic symptoms and CT findings excluding other conditions than ischemia. MRI was performed with a 1.5 T magnet with echo-planar gradients. All the patients underwent follow-up CT and/or MRI. RESULTS: Diffusion MRI, performed in the acute phase, showed signal changes in all the patients whose infarction was later confirmed by CT or MRI. In 10 of 12 patients with positive diffusion imaging, CT was normal. FLAIR sequences showed the lesions in 4 of 12 cases. In the 2 patients with transient ischemic attack diffusion MRI was normal as well as follow-up examinations. Apparent Diffusion Coefficients values in the infarcted area were almost half those of the contralateral normal brain. Final damage (as assessed by CT or MRI) was larger than observed in acute diffusion images in all cases but one. CONCLUSION: Because of its high sensitivity and specificity, diffusion MRI is going to play a more important role in the management of acute ischemic stroke patients.

Acute Disease↗

PubMed2000

Diffusion control of protein phosphorylation in signal transduction pathways.

Multiple signalling proteins are phosphorylated and dephosphorylated at separate cellular locations, which potentially causes spatial gradients of phospho-proteins within the cell. We have derived relationships that enable us to estimate the extent to which a protein kinase, a phosphatase and the diffusion of signalling proteins control the protein phosphorylation flux and the phospho-protein gradient. Two different cellular geometries were analysed: (1) the kinase is located on one planar membrane and the phosphatase on a second parallel planar membrane, and (2) the kinase is located on the plasma membrane of a spherical cell and the phosphatase is distributed homogeneously in the cytoplasm. We demonstrate that the control contribution of protein diffusion is potentially significant, given the measured rates for protein kinases, phosphatases and diffusion. If the distance between the membranes is 1 microm or greater, the control by diffusion can reach 33% or more, with the rest of the control (67%) shared by the kinase and the phosphatase. At distances of less than 0.1 microm, diffusion does not limit protein phosphorylation. For a spherical cell of radius 10 microm, a protein diffusion coefficient of 10(-8) cm(2). s(-1) and rate constants for the kinase and the phosphatase of approx. 1 s(-1), control over the phosphorylation flux resides mainly with the phosphatase and protein diffusion, with approximately equal contributions of each of these. The ratio of phospho-protein concentrations at the cell membrane and the cell centre (the dynamic compartmentation of the phospho-protein) is shown to be controlled by the rates of the protein phosphatase and of diffusion. The kinase can contribute significantly to the control of the absolute value of the phospho-protein gradient.

Cell Membrane↗

PubMed2002

Effect of diffusion and spatially varying predation risk on the dynamics and equilibrium density of a predator-prey system.

Starting from natural planktonic systems, we present a new mechanism involving spatial heterogeneity, and develop a new spatial structure model of planktonic predation systems. Firstly, the effect of diffusion on the dynamics of the system is investigated. We find that diffusion of only prey or both prey and predator between different patches with different predation risk may stabilize the dynamics, depending on the flow rate. Only a medium flow rate can lead to the stability of the system. Too large a rate can cause the system to approach the non-spatial limit case of a well-mixed system. Too large a rate can cause the system to approach the non-spatial limit case as a well-mixed system, which is characterized by its strongly oscillatory dynamics. When only prey diffuse, the smaller the parameter f (the proportion of the patchy volume with larger predation risk to the total volume), the more stable the system. If both populations can diffuse, however, only medium and very small f values may stabilize the system. Also, the response of the spatially averaged equilibrium densities of the system to the increasing of the flow rate is examined. With increasing flow rate, the spatial-averaged equilibrium density of prey decreases, while that of predator depends on which species can diffuse. For the case of prey diffusion only, it first remains unchanged and then slightly decreases, while it increases for the case of combinations as the flow rate increases. Our results are, qualitatively, determined by the spatially heterogeneous mechanism that we propose, and further regulated by top-down forces. Of practical importance, the results reported here indicate that which species diffuse plays a key role in the ways in which diffusion influences the dynamics and the spatial-average equilibrium densities of the system responses to the flow rate's increasing.

Animals↗

PubMed1992

[Serum 7S collagen levels in diffuse interstitial lung diseases--an index of the destruction of alveolar structure].

To examine whether alteration of 7S collagen in the alveolar basement membrane is related to the condition and prognosis of diffuse interstitial lung diseases (idiopathic interstitial pneumonia: IIP, collagen vascular diseases, sarcoidosis, and hypersensitivity pneumonitis), we measured serum 7S collagen levels in 123 patients with diffuse interstitial lung disease and other lung diseases. Patients with diffuse lung diseases (diffuse interstitial lung disease, pulmonary emphysema, and diffuse panbronchiolitis: DPB) showed significantly higher serum levels of 7S collagen than healthy normal controls. Serum 7S collagen levels in IIP and collagen vascular diseases were significantly higher than those in pulmonary emphysema and DPB. In cases of IIP, serum 7S collagen levels in the active stage were significantly higher than those in the inactive stage. Furthermore, the prognosis of patients with higher serum 7S collagen levels was significantly poorer than those of patients with lower serum 7S collagen levels. In infectious pulmonary diseases, serum 7S collagen levels of patients with adult respiratory distress syndrome (ARDS) were significantly higher than those of patients without ARDS. Autopsy specimens obtained from patients with positive serum 7S collagen showed diffuse alveolar damage and/or diffuse pulmonary hemorrhage in the alveolar areas. Immunohistochemical staining for 7S collagen showed disruption and/or loss of the alveolar basement membrane. The authors conclude that serum level of 7S collagen is useful for estimating the activity of diffuse interstitial lung diseases as an index of the destruction of alveolar structure.

Basement Membrane↗

PubMed2002

Sonographic differentiation of diffuse liver cancer from portal cirrhosis.

OBJECTIVE: To differentiate diffuse liver cancer from portal cirrhosis by using ultrasonography. METHODS: We analyzed the sonographic images of 15 patients with diffuse liver cancer and 30 patients with portal cirrhosis. RESULTS: The patients with diffuse liver cancer showed enlarged liver and obvious echo of nodules. The rate of portal embolism and swelling of lymph nodes around the porta hepatis was high. The patients with portal cirrhosis showed diminished liver and the obvious echo of fiber proliferation. The rates of spleen enlargement and ascites as well as gallbladder edema were high. CONCLUSIONS: To identify sonographic characteristics inside and outside of the liver. It is helpful in differentiating diffuse liver cancer from portal cirrhosis. The sonographic characteristics inside the liver include surface and size, node echo, echo of fibrous tissue hyperplasia. They are difficult to identify when diffuse liver cancer merges with considerable cirrhosis. The acoustic image characteristics of the two diseases overlap. Hence attention should be paid to the size of the liver, proliferation of cells of diffuse liver carcinoma. In sonographic characteristics outside the liver, embolism of the portal vein and swelling of lymph nodes in the porta hepatis are particularly useful to identify diffuse liver cancer or diffuse liver cancer combined with liver cirrhosis in particular.

Diagnosis, Differential↗

PubMedDate not supplied

Posttraumatic diffuse cerebral lesions. Relationship between clinical course, CT findings and ICP.

One hundred and fifty patients with posttraumatic diffuse cerebral lesions were reviewed. Criteria of inclusion were immediate coma and CT appearance of diffuse lesions, that were classified as follows: (a) Diffuse axonal injury (70 cases): patients with normal CT scan (50 cases) and patients with shearing injury (focal hemorrhages in corpus callosum, basal ganglia and brain stem; gliding contusions) (20 cases); (b) Diffuse brain swelling (80 cases): reduced or absent lateral ventricles, absence of 3rd ventricle and basal cisterns. Many of these patients had either subarachnoid haemorrhage or subdural blood effusion. Clinical course and mortality rate were in a ranking order in the considered groups. Patients with normal CT had a less severe coma and a better outcome than patients with shearing injury and diffuse brain swelling. There was evidence of high intracranial pressure in 75% of the patients with brain swelling, whereas no patient with normal CT had ICP elevation. Diffuse axonal injury represents a primary posttraumatic diffuse lesion. Secondary vascular involvement, due to hypoxia, shock and other unknown causes, is responsible for the appearance of vasoparesis, hyperemia and diffuse brain swelling.

Adult↗

PubMed1989

Diffuse senile plaques occur commonly in the cerebellum in Alzheimer's disease.

Diffuse senile plaques are characterized by the presence of beta protein (beta P), also called A4 protein, in a dispersed form and the apparent lack of associated dystrophic neurites or reactive glial cells. They are the most common type of senile plaque found in the cerebral cortex in Alzheimer's disease (AD), Down's syndrome (DS), and normal aging. Here is reported the frequent presence of diffuse senile plaques in the molecular layer of cerebellar cortex in AD. Typical neuritic plaques were never detected in this location, making the cerebellar molecular cortex a useful site for the study of diffuse plaques because diffuse plaques in the cerebral cortex are intermingled with neuritic plaques. Diffuse cerebellar plaques were detected by modified Bielschowsky silver stain in 47 of 100 cases of clinically and pathologically diagnosed AD and in none of 40 aged demented and nondemented controls. They were immunolabeled by antibodies to purified AD meningeal or cortical beta P, and to a synthetic beta P but not by two antibodies to the carboxyl- and amino-termini of the beta protein precursor (beta PP), which label a subgroup of cerebral cortical plaques. This latter result suggests that the beta P deposited in the cerebellar molecular layer may be derived from a form of the beta PP from which the carboxyl and amino terminal regions of the precursor have already been cleaved. Diffuse cerebellar plaques were not recognized by antibodies to neurofilaments, tau, and PHF, all of which detect dystrophic neurites in cerebral cortical neuritic plaques. Also, no association of reactive astrocytes or microglial cells with diffuse cerebellar plaques was observed. Thus, diffuse cerebellar plaques represent multifocal deposits of noncompacted beta P that cause little or no morphologic reaction in their microenvironment.

Aged↗

PubMed1995

Diffusion and perfusion MR imaging of cerebral ischemia.

Over the last few years, diffusion and perfusion magnetic resonance (MR) imaging methods have found increasing user for monitoring the effects of cerebral ischemia under clinical and experimental conditions. Blood perfusion can be visualized by studying the patency of the cerebrovascular bed (MR angiography), by recording exchange of diffusible tracers between blood and brain ([2H]water or [19F]trifluoromethane clearance), or by measuring the volume and transit time of the circulating blood (bolus track or spin-tagging imaging). In addition, changes in blood oxygenation level can be visualized by taking advantage of the susceptibility changes of the magnetic field homogeneity (functional or blood-oxygenation-level-dependent imaging). Diffusion imaging is based on the modulation of signal intensity by brain water diffusion. Recording a series of diffusion-weighted images allows calculation of the apparent diffusion coefficient (ADC) and the reconstruction of quantitative ADC images. Brain ADC changes are a function of intra-extracellular water homeostasis and therefore are a sensitive marker of ionic equilibrium. Since disturbances of ion and water homeostasis are among the first pathological alterations induced by brain ischemia, diffusion imaging is able to detect the incipient injury within minutes. Conversely, the reversal of these alterations is able to detect the incipient injury within minutes. Conversely, the reversal of these alterations is an early and reliable predictor of postischemic recovery. Applications of perfusion and diffusion imaging are reviewed in relation to the pathophysiology, the pathobiochemistry, and the therapy of evolving brain infarct after focal ischemia and the manifestation and reversal of ischemic injury during and after global ischemia.

Brain Ischemia↗

PubMed1995

[Diffusion MRI for evaluating cerebrovascular disease].

There are several new magnetic resonance (MR) technologies, which will provide data about the pathogenesis, circulatory state and cellular effects of ischemic stroke. Among them, diffusion MRI is the most promising one. This technology clearly reveals, within minutes of stroke onset, ischemic lesions which ultimately progress to infarct. The early ischemic lesions demonstrated by diffusion MRI represent regions with slower water diffusions perhaps due to intracellular water accumulation or shrinkage of the extracellular spaces resulting from ionic pump failure, spreading depression, or other mechanisms. The diffusion MRI can show not only irreversible but also reversible ischemic lesions, and therefore has a potential to discriminate salvageable tissues from irreversibly damaged tissues before a therapeutic intervention with thrombolytic and/or cytoprotective agents. The diffusion MRI can highlight only a fresh lesion, because water diffusion is decreased during several days after stroke onset. Diffusion MRI is extremely prone to motion artifacts, a major concern against clinical application. This problem can be solved by combination with an ultrafast technique, echo planar (EP) imaging. The EP diffusion MRI will become a rapid, reliable, objective and essential emergency diagnostic test in a clinical setting that will guide the development and application of acute therapeutic intervention.

Animals↗

PubMed1995

Theory of osteogenesis behavior based on calcium diffusion theory.

Osteogenesis is completed by the nucleation mechanism on crystal nuclei formation and growth after amorphous calcium phosphate accretion to collagen fibers. For nuclei formation, it is necessary to have preliminary ionic diffusion such as that of Ca2+ and PO4(3-) ions to this part. Therefore, promotion of ionic diffusion to this part is the first essential condition for osteogenesis. We have considered this phenomenon as the nucleation mechanism accompanied by preliminary diffusion behavior and shown the optimum mechanical condition on promoting this ionic diffusion. Furthermore, we noticed callus by callotasis as the typical example which fits this mechanical condition and investigated its histology. However, necking occurs at the site of callus sandwiched by cortical bones due to tensile stress, three axial tensile stress in radial and tangential directions, in addition to the tensile stress occurs at the netsection of the callus due to the constraint of cortical bones. Therefore, the size of pore along the collagen lamination and hole zone becomes large under this mechanical condition and ionic diffusion such as Ca2+, PO4(3-) is liable to occur at this part. By solving the partial differential equation of the stress-induced diffusion, diffusive particles are shown to concentrate at the high three axial tensile stress region. Therefore, a high concentrated region of Ca, PO4 is achieved and selective osteogenesis due to hydroxyapatite nucleation is considered to progress in this region. Histological investigation of the callus of rabbit showed that mineralization occurs at this site and supports the theory of stress-induced diffusion on osteogenesis behavior.

Animals↗

PubMed2006

Glucose partition coefficient and diffusivity in the lower skin layers.

PURPOSE: This work aims to estimate the diffusivity and partitioning of glucose in the dermis and the viable epidermis of human skin. METHODS: The partition coefficient of glucose between phosphate-buffered saline and dermis, tape-stripped epidermis (TSE), stratum corneum (SC), and split-thickness skin, was measured in vitro using human cadaver skin. Glucose permeability across dermis and tape-stripped split-thickness skin (TSS) was measured using side-by-side diffusion cells. Glucose desorption from TSE and human epidermal membrane (HEM) was measured. All measurements were conducted at 32 degrees C. RESULTS: The partition coefficient for glucose [mean +/- SD (no. of samples)] was 0.65 +/- 0.09 (n = 25) for dermis, 0.81 +/- 0.06 (n = 10) for TSE, and 0.53 +/- 0.12 (n = 9) for SC. Glucose diffusivity in dermis was calculated to be 2.64 +/- 0.42 x 10(-6) cm2/s (n = 14). Glucose diffusivities in the viable epidermis estimated from TSS permeation, TSE desorption, and HEM desorption were 0.075 +/- 0.050 x 10(-6) cm2/s (n = 5), 0.037 +/- 0.018 x 10(-6) cm2/s (n = 4), and 1.0 +/- 0.6 x 10(-6) cm2/s (n = 4), respectively. CONCLUSION: The tissue/buffer partition coefficient of glucose in all skin layers was found to be less than unity, suggestive of excluded volumes in each layer. Glucose diffusivity in human dermis was found to be one third of its value in water, indicative of hindered diffusion related to the structural components of the tissue. A substantially lower value for glucose diffusivity in viable epidermis is suggested.

Buffers↗

PubMed2006

76-space analysis of grey matter diffusivity: methods and applications.

Diffusion-weighted imaging (DWI) and diffusion tensor imaging (DTI) allow in vivo investigation of molecular motion of tissue water at a microscopic level in cerebral gray matter (GM) and white matter (WM). DWI/DTI measure of water diffusion has been proven to be invaluable for the study of many neurodegenerative diseases (e.g., Alzheimer's disease and Creutzfeldt-Jakob disease) that predominantly involve GM. Thus, quantitative analysis of GM diffusivity is of scientific interest and is promised to have a clinical impact on the investigation of normal brain aging and neuropathology. In this paper, we propose an automated framework for analysis of GM diffusivity in 76 standard anatomic subdivisions of gray matter to facilitate studies of neurodegenerative and other gray matter neurological diseases. The computational framework includes three enabling technologies: (1) automatic parcellation of structural MRI GM into 76 precisely defined neuroanatomic subregions ("76-space"), (2) automated segmentation of GM, WM and CSF based on DTI data, and (3) automatic measurement of the average apparent diffusion coefficient (ADC) in each segmented GM subregion. We evaluate and validate this computational framework for 76-space GM diffusivity analysis using data from normal volunteers and from patients with Creutzfeldt-Jakob disease.

Adult↗

PubMed2005

Diagnostic value of diffusion-weighted magnetic resonance imaging in pediatric cerebral diseases.

The purpose of this study was to detect the diagnostic value of diffusion-weighted magnetic resonance imaging in different pediatric cerebral diseases involving the cerebral white and gray matter and to compare the diffusion properties with age-matched normal children. Conventional and diffusion-weighted magnetic resonance imaging were performed in 21 children with various neurologic disorders and 25 normal control subjects. Apparent diffusion coefficients were measured from the brain lesions and 12 normal-appearing white and gray matter areas in the study group. Twelve normal-appearing areas were also measured in the control group. Apparent diffusion coefficient values obtained from the normal subjects were similar to values described in the literature but were significantly different from the control subjects. Apparent diffusion coefficient values for the neurodegenerative disease group (n = 8), the anoxic encephalopathy group (n = 4), the subacute sclerosing panencephalitis group (n = 4), the acute disseminated encephalomyelitis group (n = 3), and the encephalitis group (n = 2) were respectively between 0.29-1.85 x 10(-5) cm2/s, 0.13-1.87 x 10(-5) cm2/s, 0.96-1.57 x 10(-5) cm2/s, 0.49-0.73 x 10(-5) cm2/s, and 0.42-1.50 x 10(-5) cm2/s. Although this study is limited because of the size of the patient sample and disease heterogeneity, diffusion-weighted magnetic resonance imaging provides useful and complementary information regarding the degree of involvement in different pediatric neurologic disorders.

Diffusion↗

PubMed1975

Analysis of factors determining the resistance to diffusion in patients with liver cirrhosis.

In 5 patients with liver cirrhosis the measured pulmonary diffusing capacity for oxygen (DLo2) was related to the diffusing capacity of the pulmonary membrane (DM) and to the volume of blood in the pulmonary capillary bed (Vc) as estimated from the measured pulmonary blood flow (Qc) and the value of the presumptive transit time. DL and DM were found to be diminished in 4 of the 5 cases, DM being only once 1,7 times greater than DL. The relationship between the resistance of the red blood cells to diffusion and the resistance of the pulmonary membrane to diffusion (see journal for formula) ranged between 5 and 35% indicating that the resistance of the pulmonary membrane to the uptake of O2 was of greater importance than the resistance of the red cells. A correlation was found to exist between D/Q and DM/ThetaVc (diffusing capacity/blood flow and membrane diffusing capacity/diffusing capacity of the red cells in the pulmonary capillary bed). The possible site and nature of the diffusion defect is discussed.

Adult↗

PubMed2002

Monitoring disease progression in CADASIL with diffusion magnetic resonance imaging: a study with whole brain histogram analysis.

BACKGROUND AND PURPOSE: In cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), a large increase in water diffusion has been found both inside and outside the cerebral lesions as detected on conventional MRI. The aim of the present study was to assess the sensitivity of diffusion tensor imaging for monitoring the progression of cerebral tissue damage during the course of CADASIL. METHODS: With the use of diffusion tensor imaging, whole brain trace of the diffusion tensor [Trace(D)] histograms were obtained in 22 CADASIL patients and 12 age-matched controls at baseline, in 14 patients after a mean delay of 21 months, and in 5 controls after a mean delay of 29 months. Parameters derived from these histograms (mean value, peak height, and peak location) were analyzed at baseline and during the follow-up. RESULTS: At baseline, all the histogram parameters differed between patients and controls and were found to be significantly correlated with both the Mini-Mental State Examination score and Rankin Scale score in the patient group. The follow-up study showed a decrease in the peak height associated with an increase in the mean value of whole brain Trace(D) histograms in the 14 CADASIL patients scanned twice. The diffusion changes appeared larger in the patients whose Rankin score increased during the study period. CONCLUSIONS: These results suggest that the measurement of water diffusion over time is a sensitive marker for the progression of tissue damage in the brain. Thus, quantitative diffusion MRI can be used to monitor disease progression in CADASIL and possibly in other types of small-vessel brain disorders.

Adult↗

PubMed2005

Quantification of cervical cord pathology in primary progressive MS using diffusion tensor MRI.

OBJECTIVE: To investigate the extent and severity of cervical cord damage using diffusion tensor MRI (DT-MRI) and histogram analysis in patients with primary progressive MS (PPMS). METHODS: Diffusion-weighted sensitivity-encoded (SENSE) echoplanar images of the cervical cord and brain dual-echo and diffusion-weighted scans were acquired from 24 patients with PPMS and 13 healthy controls. Cord and brain mean diffusivity and fractional anisotropy histograms were produced. An analysis of variance model, adjusting for cord volume, was used to compare cord DT-MRI parameters from controls and patients. RESULTS: Compared to healthy controls, PPMS patients had reduced cervical cord cross-sectional area and average cord fractional anisotropy (p = 0.007), and increased cord mean diffusivity (p = 0.024). No correlations were found between DT-MRI metrics of the cord and quantities obtained from conventional and DT-MRI of the brain. CONCLUSIONS: DT-MRI of the cervical cord can quantify the extent of diffuse cord pathology in patients with PPMS. Such cord diffusivity changes in patients with PPMS are likely to reflect irreversible axonal injury and reactive gliosis and seem to be independent of brain damage.

Adult↗