| 1. |
- Bjerner, Tomas
(författare)
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Assessment of Myocardial Perfusion with Magnetic Resonance Imaging and an Intravascular Contrast Agent
- 2001
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The intravascular contrast agent NC100150 Injection (Clariscan™) was tested for its ability to induce signal intensity changes in myocardium, both in steady state and during first pass, and thereby demarcating non-perfused myocardium from perfused. Steady state: Ex vivo in pigs and when using 4 mg Fe/kg bodyweight (b.w.) of the contrast agent, a T1-weighted inversion recovery fast spin echo (IR/TSE) sequence could demarcate 95% of the volume of non-perfused myocardium when compared with the volume determined from photographs where non-perfused myocardium was demarcated by fluorescein. A T2*-weighted gradient echo sequence resulted in significantly lower volume estimations of non-perfused myocardium. Under similar conditions and when using 5 mg Fe/kg b.w., a T2-weighted fast spin echo (TSE) demarcated 99% of the volume of non-perfused myocardium. We were not able to implement the IR/TSE sequence in vivo, but the T2-weighted TSE resulted in clear visualization of non-perfused myocardium in vivo in animals. First pass: With a single-shot T2-TSE, one slice was acquired every heartbeat during the first pass of the contrast agent. When using this sequence, non-perfused myocardium was demarcated in animals and the induced signal intensity changes in perfused myocardium (74±18% @ 5 mg Fe/kg b.w.) were comparable to those in patients (59±13 @ 3 mg Fe/kg b.w.), when taking differences in doses into account. Linear dose–response was found in porcine myocardium between R1, R2, and R2* versus dose (0 – 12 mg Fe/kg b.w.) ex vivo and for R1 (in myocardium and blood) versus dose (0 – 5 mg Fe/kg b.w.) in vivo. However, R1 determination in vivo and in the box ex vivo indicated that blood loss (<2/3) from the myocardium occured during the excision of the heart and preparation for the box, meaning that the box situation ex vivo actually corresponds to lower doses in vivo. Finally, the in vivo measurements of R1 in myocardium and blood indicated that at R1 values in blood as high as 13 s-1, the water exchange is in the fast regime through the capillary wall. In conclusion, the feasibility of NC100150 Injection, in steady state and during first pass, for demarcation of non-perfused myocardium when using a T2-weighted TSE sequence has been demonstrated.
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| 2. |
- Çiray, Ipek
(författare)
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Diagnosis and evaluation of therapeutic response of bone metastases.
- 2001
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The aim of this study was to investigate different aspects of different imaging modalities in the diagnosis of bone metastases and in the assessment of their response to therapy. The role of CT, with and without clinical information, was investigated as compared to CT-guided bone biopsy in the evaluation of suspected bone metastases. The diagnostic accuracy of CT alone (44%) increased to 82% when clinical information was taken into account, especially for the lesions diagnosed histopathologically as benign. In most cases, CT in combination with clinical information gave enough information about the nature (malignant or benign) of a bone lesion. In uncertain cases the diagnostic accuracy could be improved by means of CT-guided bone biopsy. Possible misinterpretation of new sclerotic lesions when judged according to the WHO criteria during treatment was studied. One hundred and thirty-nine breast cancer patients with bone metastases, who participated a the clinical trial of clodronate therapy, were studied retrospectively. In 8 of the 24 patients considered at conventional radiography to have progressive disease according to WHO criteria, 17 of 52 apparently new sclerotic lesions (33%) were detected on previous bone scintigraphy. WHO criteria may give rice to misinterpretations in patients with new sclerotic lesions. For better assessment more sensitive techniques, e.g. bone scintigraphy, can be used as a complement to conventional radiography. Eighteen breast cancer patients with known bone metastases were studied prospectively regarding evaluation of therapy response. T1-weighted spin echo (SE) and fat-suppressed long echo time inversion recovery turbo spin echo (long TE IR-TSE) MR sequences, conventional radiography, bone scintigraphy and CT-guided bone biopsy were performed before and during systemic chemotherapy. T1-weighted sequences and long TE IR-TSE sequences were compared regarding evaluation of early response of breast cancer bone metastases to chemotherapy, using a combination of clinical, radiographic and scintigraphic examinations as a reference. Therapeutic response evaluation with MR imaging was based on change in tumor size assessed quantitatively by measuring all focal metastases, and on change in pattern and signal intensity (SI) of the metastases, assessed visually. The long TE IR-TSE sequence demonstrated partial response of breast cancer bone metastases to chemotherapy more accurately than the T1-weighted sequence (58% vs. 17%). The effect of granulocyte colony-stimulating factor (G-CSF)-supported chemotherapy on MR images of normal red bone marrow was investigated. A diffuse, homogeneous SI increase was observed visually and quantitatively in initially normal bone marrow during G-CSF therapy, obscuring some focal lesions. No such SI change was visible after G-CSF therapy or in patients not receiving G-CSF. We concluded that G-CSF-supported chemotherapy might induce diffuse SI changes in normal red bone marrow on MRI, and that this might lead to misinterpretations in the evaluation of response of bone metastases. Early response of bone metastases to therapy was assessed in targeted metastatic lesions in breast cancer patients with T1-weighted and long TE IR-TSE MR sequences and CT compared with histopathological findings. The results indicated that the SI increase in the metastatic lesions following therapy on long TE IR-TSE images might be useful in indicating an early response. T1-weighted images are of limited value in assessing alterations in the amount of tumor cells. An increase in electron density on CT can be seen in both responding and progressing lesions.
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| 3. |
- Olsson, Britt-Marie, et al.
(författare)
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Resultat från inventeringar av flodpärlmussla i Värmlands län 2008-2011
- 2011
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Flodpärlmusslan, Margaritifera margaritifera, är en fridlyst och rödlistad art som är föremål för Naturvårdsverkets åtgärdsprogram. För att kunna utföra relevanta skydds-, restaurerings och skötselåtgärder i Värmlands län, behövs bland annat ett förbättrat underlag om artens förekomst i länet. Genom Naturvårdsverkets anslag för arbete med åtgärdsprogram, miljöövervakning samt EU´s ramdirektiv för vatten (2000/60/EG) möjliggjordes en länsinventering av flodpärlmussla.Denna rapport redovisar resultatet från de inventeringar som utförts av Länsstyrelsen i Värmlands län under åren 2008-2011 samt de, fram till idag, kartlagda bestånd av flodpärlmussla i Värmlands län. De valda vattendragen för inventeringen prioriterades bland annat utifrån rykten om förekomst, anknytning till kända bestånd och klassning som särskilt värdefull vattenförekomst. Två personer har vadat uppströms cirka 90 mil vattendrag under fyra somrar för att med lampförsedd vattenkikare söka musslor. Alla fynd har rapporterats in till musselportalen.Värmlands län har idag 44 kända vattendrag med bestånd av flodpärlmussla. Av totalt ca 180 inventerade vattendrag i länet upptäcktes 9 vattendrag med bestånd av flodpärlmussla, vilket ger en fyndfrekvens på ca 4 %. De nya fynden består till största delen av enstaka individer och dessa små populationer bör skyddas och säkerställas för framtiden med olika naturvårdande åtgärder. Flera djupa vattendrag har inte inventerats än, men dessa kräver hjälp av båt, kamera och dykning.
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