Objective
To compare integrated slice-specific dynamic shim (iShim) with distortion correction post-processing to conventional 3D volume shim for the reduction of artefacts and signal loss in 1.5 T whole-body diffusion-weighted imaging (WB-DWI).
Methods
Ten volunteers underwent WB-DWI using conventional 3D volume shim and iShim. Forty-eight consecutive patients underwent WB-DWI with either volume shim (n = 24) or iShim (n = 24) only. For all subjects, displacement of the spinal cord at imaging station interfaces was measured on composed b = 900 s/mm2 images. The signal intensity ratios, computed as the average signal intensity in a region of high susceptibility gradient (sternum) divided by the average signal intensity in a region of low susceptibility gradient (vertebral body), were compared in volunteers. For patients, image quality was graded from 1 to 5 (1 = Poor, 5 = Excellent). Signal intensity discontinuity scores were recorded from 1 to 4 (1 = 2 + steps, 4 = 0 steps). A p value of < 0.05 was considered significant.
Results
Spinal cord displacement artefacts were lower with iShim (p < 0.05) at the thoracic junction in volunteers and at the cervical and thoracic junctions in patients (p < 0.05). The sternum/vertebra signal intensity ratio in healthy volunteers was higher with iShim compared with the volume shim sequence (p < 0.05). There were no significant differences between the volume shim and iShim patient groups in terms of image quality and signal intensity discontinuity scores.
Conclusion
iShim reduced the degree of spinal cord displacement artefact between imaging stations and susceptibility-gradient-induced signal loss.
UNITED Policyholder Group v Attorney General for Trinidad and Tobago [2016] UKPC 17 provided the Privy Council with its second opportunity in recent years to consider the doctrine of legitimate expectations (the first being Paponette v Attorney General of Trinidad and Tobago [2010] UKPC 32; [2012] 1 A.C. 1). The appellants were a group of individuals who held policies in a company known as the Colonial Life Insurance Company (CLICO). On learning in 2009 that CLICO was in serious financial difficulty, the then Government of Trinidad and Tobago had publicly issued a number of assurances to the effect that it would undertake a vast restructuring programme in order to ensure that CLICO's contractual liabilities to such policyholders were fulfilled. Following its election in 2010, the new Government changed direction; it found that CLICO's financial difficulties were much graver than had been originally anticipated and, accordingly, determined that the Government would take a different course with the consequence that CLICO's liabilities would be fulfilled to a less generous degree than originally represented.
This article has two aims. Firstly, it explores a body of modern challenges to administrative reason‐giving, decided in the five‐year period 2014–2018. Three main themes are drawn out: outright failures to give reasons now seem to be a rare occurrence; a number of considerations help to ensure that at least an outline of reasons is usually offered by decision‐makers; common law fairness plays a limited role in testing the adequacy of reasons. Secondly, it addresses the question of why the courts have not embraced a ‘general common law duty to give reasons.’ Four factors are discussed: doubts that introducing a general duty would add something of substance to the law; difficulties inherent in developing a general formulation of the reasons required; weaknesses in the ‘hortatory’ case for a general duty and weaker commitment on the part of judges than academics to generality as a central feature of administrative law doctrine.
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