Advancements in DSC and BOLD perfusion imaging: Acquisition, analysis and clinical application

• This thesis is focused on perfusion MRI techniques and topics related to image acquisition, analysis and clinical applications. The first half of the thesis is focused on dynamic susceptibility contrast (DSC) MRI, a technique which is based on the contrast enhancements caused by an intravenously administered paramagnetic contrast agent. The second half of this thesis is focused on blood oxygen level dependent (BOLD) MRI, which leverages a signal effect caused by paramagnetic properties of venous blood. For application in peripheral muscle, this signal effect can be enhanced by restricting the blood flow of a feeding artery to the studied tissue. In papers I and III, it is shown that the duration of the contrast agent injection and the duration of the flow restriction, indeed affects the measures of perfusion produced with these techniques. The pathophysiology of normal pressure hydrocephalus (iNPH) is not completely understood, but symptoms point toward brain stem regions. In paper II, DSC-MRI and diffusion MRI was applied to patients with iNPH, pre and post shunt-surgery, showing the possible involvement of these regions in iNPH symptoms and disease reversibility. In paper IV peripheral muscle BOLD was applied to patients with peripheral artery disease (PAD) and controls, in an exploratory study. Perfusion related measures derived from acquired BOLD curves were able to separate between PAD patients and controls, in accordance with previous studies. Further data exploration found a number of curve traits that could be indicative of potential disease phenotypes, and these have now been documented. As the technique continues to develop towards individual prognostication, these curve traits may be of value for establishing disease severity. In conclusion, this work has made advancements of the common knowledge base within the field of perfusion imaging, spanning from the well-studied area of DSC-MRI to the comparatively new technique of peripheral muscle BOLD imaging and their application to clinically relevant patient cohorts.

Ämnesord

MEDICIN OCH HÄLSOVETENSKAP  -- Klinisk medicin -- Radiologi och bildbehandling (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Clinical Medicine -- Radiology, Nuclear Medicine and Medical Imaging (hsv//eng)

Nyckelord

Magnetic Resonance Imaging

Cerebral Blood Flow

Cerebral Blood Volume

Time To Peak

Biophysical modelling

Signal representation

MRI

Publikations- och innehållstyp

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