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Per-Lennart A Westesson

Publications and source records attributed to Per-Lennart A Westesson.

8 recordsLinked to original sources
PubMed2006

Fractional anisotropy is higher in Heschl's gyrus than in superior temporal gyrus in normal subjects.

RATIONALE AND OBJECTIVES: The first Heschl's gyrus (HG) is believed to receive the core projection of the acoustic radiation. We examined if it were possible to differentiate the subcortical white matter of the HG from the superior temporal gyrus (STG) using diffusion tensor (DT) imaging. MATERIALS AND METHODS: The study was approved and informed consent was obtained in accordance with the guidelines of our Institutional Review Board for human subject studies. We examined six healthy adult volunteers with DT images using 20 orientations and repeated 11 times. The fractional anisotropy (FA) and the apparent diffusion coefficient (ADC) were calculated. RESULTS: The mean FA of the subcortical white matter of the HG (0.37) was higher than that of the STG (0.27) on both sides (P < .01). There was no statistically significant difference when comparing left and right HG and STG (P > .05). There was no statistically significant difference in mean ADC of the HGs and STGs (0.75 x 10(-3) mm(2)/sec, P > .05). CONCLUSIONS: The FA in the subcortical white matter of the HG was higher than that of the STG in both hemispheres. These changes in DT imaging may be accounted for by the presence of the auditory radiations.

Adult↗
PubMed2005

Clinically silent choroid plexus cyst: evaluation by diffusion-weighted MRI.

We retrospectively reviewed diffusion-weighted magnetic resonance images of 57 patients with a choroid plexus cyst diagnosed by contrast-enhanced T1-weighted imaging. All the cysts appeared to represent incidental findings. Thirty-eight of 57 patients had bilateral cysts and 19 had unilateral ones. On diffusion-weighted images, 78 of 95 cysts showed homogeneously high signal intensity, 12 showed focal high signal areas, and 5 had no portion with a high signal. The apparent diffusion coefficient of the high signal areas in the cysts was (1.46+/-0.14) x10(-3) mm(2)/s, intermediate between the apparent diffusion coefficients of cerebrospinal fluid and cerebral white matter, (3.15+/-0.67) x10(-3) and (0.79+/-0.22) x10(-3) mm(2)/s, respectively. Pathological correlation was available in one case, showing high signal intensity areas in the glomera of the choroid plexuses in the lateral ventricles on diffusion-weighted images corresponding to gelatinous cysts with highly proteinaceous content.

Adult↗
PubMed2005

Conspicuity of diffuse axonal injury lesions on diffusion-weighted MR imaging.

OBJECTIVE: (1) To detect diffuse axonal injury (DAI) lesions by diffusion-weighted imaging (DWI), as compared with fluid-attenuated inversion recovery (FLAIR) imaging and (2) to evaluate hemorrhagic DAI lesions by b0 images obtained from DWI, as compared with gradient-echo (GRE) imaging. METHODS: We reviewed MR images of 36 patients with a diagnosis of DAI. MR imaging was performed 20 h to 14 days (mean, 3.7 days) after traumatic brain injury. We evaluated: (1) conspicuity of lesions on DWI and FLAIR and (2) conspicuity of hemorrhage in DAI lesions on b0 images and GRE imaging. RESULTS: DWI clearly depicted high-signal DAI lesions. The sensitivity of DWI to lesional conspicuity in DAI lesions was almost equal to that of FLAIR. The sensitivity of b0 images to identification of hemorrhagic DAI lesions was inferior to that of GRE. CONCLUSION: DWI is as useful as FLAIR in detecting DAI lesions. GRE imaging is still the superior tool for the evaluation of hemorrhagic DAI.

Adolescent↗
PubMed2005

Kyphoplasty versus vertebroplasty to increase vertebral body height: a cadaveric study.

PURPOSE: To prospectively compare the vertebral height restoration achieved with kyphoplasty and vertebroplasty in fresh cadavers by using multi-detector row computed tomography (CT). MATERIALS AND METHODS: Institutional review board approval was not required because the donors had registered in and consented to an anatomic gift program prior to their death. Thirty-seven vertebrae were harvested from four donated cadavers of elderly female individuals (mean age, 82 years; age range at death, 73-87 years). The vertebrae were dissected free of the surrounding muscles and imaged with multi-detector row CT. Compression fractures were induced, and the vertebrae were again imaged. The vertebrae were randomized to be treated with kyphoplasty (n = 19) or vertebroplasty (n = 18) and were then imaged at multi-detector row CT. The anterior, central, and posterior vertebral body heights and wedge angles were measured in the midsagittal plane of the reformatted images. The amount of cement injected was determined by weighing the vertebrae before and after treatment. The statistical significance of changes in vertebral body height, wedge angle, and weight with the two treatment techniques was evaluated with the independent t test or Mann-Whitney U test. RESULTS: The increase in vertebral height was greater with kyphoplasty than with vertebroplasty (5.1 mm vs 2.3 mm, respectively; P < .05). The original vertebral height was restored in 93% of vertebrae with kyphoplasty and in 82% with vertebroplasty (P < .05). There was a greater decrease in wedge angle with kyphoplasty than with vertebroplasty (3.1 degrees vs 1.6 degrees, respectively); however, this difference was not significant (P > .05). There was no significant difference in the amount of cement injected with kyphoplasty and vertebroplasty (P > .05). CONCLUSION: Kyphoplasty increased vertebral body height more than vertebroplasty in this model of acutely created fractures in fresh cadaver specimens.

Aged↗
PubMed2002

Secondary degeneration of the substantia nigra and corticospinal tract after hemorrhagic middle cerebral artery infarction: diffusion-weighted MR findings.

Middle cerebral artery (MCA) infarction involving the striatum can cause secondary degeneration of the substantia nigra and corticospinal tract. We present a patient with subacute hemorrhagic MCA infarction in whom diffusion-weighted MR images showed high signal intensity in the ipsilateral substantia nigra and corticospinal tract. A corresponding apparent diffusion coefficient map revealed a uniformly decreased signal in the same area. This represents secondary degeneration and should not be mistaken for other pathological conditions, such as a new infarction.

Aged↗
PubMedDate not supplied

Diffusion-weighted MR imaging of posterior reversible leukoencephalopathy syndrome: a pictorial essay.

Posterior reversible leukoencephalopathy syndrome is characterized by reversible white matter lesions. However, ischemic injury with irreversible damage may occur. This pictorial essay illustrates MR features associated with posterior reversible leukoencephalopathy syndrome. We will emphasize the role of diffusion-weighted imaging for the discrimination of irreversible ischemic injury from reversible vasogenic edema.

Adult↗
PubMedDate not supplied

CNS vasculitis and vasculopathy: efficacy and usefulness of diffusion-weighted echoplanar MR imaging.

This pictorial essay illustrates the usefulness of diffusion-weighted imaging (DWI) on various vasculitis or vasculopathies, including systemic lupus erythematosus (SLE), Behçet's disease, Churg-Strauss disease, primary angitis of the central nervous system (PACNS), giant cell arteritis, infectious vasculitis, sickle cell disease, drug-induced vasculopathy and hypertensive vasculopathy. DWI proves to detect small and active ischemic changes not visible on conventional MRI, and it clearly discriminates cytotoxic from vasogenic edema in patients with cerebral vasculitis or vasculopathy. DWI seems useful in assessing the treatment and patient outcome.

Adult↗