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- Elfgren, Christina, et al.
(author)
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fMRI activity in the medial temporal lobe during famous face processing
- 2006
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In: NeuroImage. - : Elsevier BV. - 1095-9572 .- 1053-8119. ; 30:2, s. 609-616
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Journal article (peer-reviewed)abstract
- The current event-related fMRI study examined the relative involvement of different parts of the medial temporal lobe (MTL), particularly the contribution of hippocampus and perirhinal cortex, in either intentional or incidental recognition of famous faces in contrast to unfamiliar faces. Our intention was to further explore the controversial contribution of MTL in the processing of semantic memory tasks. Subjects viewed a sequence of famous and unfamiliar faces. Two tasks were used encouraging attention to either fame or gender. In the fame task, the subjects were requested to identify the person when seeing his/her face and also to try to generate the name of this person. In the gender task, the subjects were asked to conduct a judgement of a person's gender when seeing his/her face. The visual processing was hence directed to gender and thereby expected to diminish attention to semantic information leading only to a “passive” registration of famous and non-familiar faces. Recognition of famous faces, in both contrasts, produced significant activations in the MTL. First, during the intentional recognition (the person identification task) increased activity was observed in the anterolateral part of left hippocampus, in proximity to amygdala. Second, during the incidental recognition of famous faces (the gender classification task), there was increased activity in the left posterior MTL with focus in the perirhinal cortex. Our results suggest that the hippocampus may be centrally involved in the intentional retrieval of semantic memories while the perirhinal cortex is associated with the incidental recognition of semantic information.
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- Jarnum, Hanna, et al.
(author)
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Färre DT och fler MR vid skallundersökning på små barn. Svårt avgöra om larmrapport påverkat val av metod, visar studie från Lund
- 2006
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In: Läkartidningen. - 0023-7205. ; 103:23, s. 3-1840
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Journal article (peer-reviewed)abstract
- In January 2004, Per Hall et al in an article in British Medical Journal stated that children under the age of 18 months, who underwent CT of the brain, could get negative effects on cognitive abilities in adulthood. At the Department of Radiology, Lund University Hospital, 55 children under the age of 18 months underwent CT of the brain during 2004 compared to 70 children in 2003. MRI of the brain in the same age group increased in number from 52 in 2003, to 63 in 2004. CT of the brain after head trauma decreased with almost 50 % in 2004, compared to 2003. MRI is now the modality of choice for elective radiological evaluation of the brain in small children. However, CT is recommended as an emergency examination in head trauma to obtain a diagnosis without delay and to enable detection of child abuse. If the child already has undergone one or several CT examinations of the brain, MRI should be preferred to avoid further exposure to ionizing radiation. Optimization of radiation dose levels for CT of the brain in children is needed.
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- Stenberg, Lars, et al.
(author)
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Dynamic Susceptibility Contrast-Enhanced Perfusion Magnetic Resonance (MR) Imaging Combined with Contrast-Enhanced MR Imaging in the Follow-up of Immunogene-Treated Glioblastoma Multiforme.
- 2006
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In: Acta Radiologica. - : SAGE Publications. - 1600-0455 .- 0284-1851. ; 47:8, s. 852-861
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Journal article (peer-reviewed)abstract
- Purpose: To assess the value of the combined use of dynamic susceptibility contrast-enhanced perfusion magnetic resonance imaging (MRI) and conventional contrast-enhanced MRI for the follow-up of treatment of glioblastoma multiforme (GBM). Material and Methods: 79 examinations were performed in six surgically and immunogene-treated patients and two surgically treated patients. Ratios of the relative cerebral blood volume (rCBV) in lesions and in the contralateral normal-appearing white matter were calculated. The regions with elevated rCBV were compared with those with contrast enhancement. Tissue specimens from surgical biopsies and autopsies were studied histopathologically. Results: The lesion-to-normal rCBV ratios were high in the tumors prior to operation (7.3 to 18.2) as well as in the recurrent tumors (1.6 to 13.2). The volumes of the regions with elevated rCBV were similar to those with contrast enhancement in 63 of the 79 examinations. However, in 11 of 79 examinations, the regions with high rCBV were smaller than the regions with contrast enhancement ("mismatch"). In two samples from the immunogene-treated patients this was correlated with the histopathological finding of malignant tumor with numerous proliferating GBM vessels with multiple minimal lumina, sometimes thrombotized or ruptured. These vessels may have increased permeability with contrast enhancement not accompanied by increased microvascular volume. Conclusion: 1) Elevated rCBV on perfusion MRI corresponding to the contrast-enhancing lesion supports the diagnosis of recurrent malignant tumor. 2) A mismatch showing a volume of rCBV elevation smaller than that of contrast enhancement can be seen in particularly aggressive tumor growth and is thus not always a sign of reactive non-tumor changes. 3) The combination of perfusion MRI and conventional contrast MRI provides useful information in the follow-up of glioblastoma multiforme treatment.
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- Törnqvist, Erna, et al.
(author)
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It's like being in another world--patients' lived experience of magnetic resonance imaging.
- 2006
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In: Journal of Clinical Nursing. - : Wiley. - 1365-2702 .- 0962-1067. ; 15:8, s. 954-961
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Journal article (peer-reviewed)abstract
- Aim. The aim of this study was to illuminate patients' lived experience during magnetic resonance imaging. Background. Magnetic resonance imaging has increased in importance since the early 1980s and is today a common useful diagnostic tool. Although magnetic resonance imaging are non-invasive and considered painless, many patients experience anxiety, sometimes so strong that the scan has to be terminated. Design and methods. The study had an inductive design and a hermeneutic phenomenological methodology was used. Results. The essential theme of going through magnetic resonance imaging was a feeling of being in another world. The strange environment and isolation inside the scanner made the participants' experiences unusual, with varying degrees of difficulty dealing with it. Being in the other world caused a threat to the participants' self-control. There was a relation between threat to self-control, effort and need for support in the sense that the magnitude of threat to self-control had an impact on the effort it took to handle the situation and on the need for support, and conversely that the support received could affect the effort and threat to self-control. Conclusions. The study shows that the information received and the interaction between patients and staff have a significant influence on patients' lived experiences. Relevance to clinical practice. The individual experience of threat to self-control requires the need for support to be individualized and care need to be adjusted for each patient.
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- van Westen, Danielle, et al.
(author)
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Tumor extension in high-grade gliomas assessed with diffusion magnetic resonance imaging: values and lesion-to-brain ratios of apparent diffusion coefficient and fractional anisotropy.
- 2006
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In: Acta Radiologica. - : SAGE Publications. - 1600-0455 .- 0284-1851. ; 47:3, s. 311-319
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Journal article (peer-reviewed)abstract
- Purpose: To determine whether the apparent diffusion coefficient (ADC) and fractional anisotropy (FA) can distinguish tumor-infiltrated edema in gliomas from pure edema in meningiomas and metastases. Material and Methods: Thirty patients were studied: 18 WHO grade III or IV gliomas, 7 meningiomas, and 5 metastatic lesions. ADC and FA were determined from ROIs placed in peritumoral areas with T2-signal changes, adjacent normal appearing white matter (NAWM), and corresponding areas in the contralateral healthy brain. Values and lesion-to-brain ratios from gliomas were compared to those from meningiomas and metastases. Results: Values and lesion-to-brain ratios of ADC and FA in peritumoral areas with T2-signal changes did not differ between gliomas, meningiomas, and metastases (P = 0.40, P = 0.40, P = 0.61, P = 0.34). Values of ADC and FA and the lesion-to-brain ratio of FA in the adjacent NAWM did not differ between tumor types (P = 0.74, P = 0.25, and P = 0.31). The lesion-to-brain ratio of ADC in the adjacent NAWM was higher in gliomas than in meningiomas and metastases (P = 0.004), but overlapped between tumor types. Conclusion: Values and lesion-to-brain ratios of ADC and FA in areas with T2-signal changes surrounding intracranial tumors and adjacent NAWM were not helpful for distinguishing pure edema from tumor-infiltrated edema when data from gliomas, meningiomas, and metastases were compared.
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