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20-05 MR Imaging Strikes Roots

he news of Lauterbur's invention traveled slowly although he presented it at a number of scientific meetings between 1972 and 1975. Some people lis­ten­ed, understood, and reacted. It's a tale of international conferences.

Here are some examples:

In April 1974, Lauterbur gave a talk at a conference in Raleigh, North Carolina. This conference was attended by Richard Ernst from Zurich (Figure 20-31), who realized that instead of Lauterbur's back-projection one could use switched magnetic field gradients in the time domain.

Figure 20-31:
Richard Ernst (1933-2021).

This led to the 1975 publication NMR Fourier Zeugmatography by Anil Kumar, Dieter Welti, and Richard Ernst [⇒ Kumar 1975], and to the universal re­con­struc­tion method for MR imaging today (Figure 20-32).

Figure 20-32:
One of the first 2D-FT MR images from the research group of Richard Ernst in Zurich, acquired by Anil Kumar in July 1974.

When Lauterbur presented his approach to NMR imaging at the In­ter­na­tio­nal Society of Magnetic Resonance (ISMAR) meeting in January 1974 in Bom­bay, Raymond Andrew, William Moore, and Waldo Hinshaw from the University of Nottingham, England, were in the audience and took note.

spaceholder redAs a result, Hin­shaw (Figure 20-33) developed his own approach to MR imaging with his sensitive point me­thod [⇒ Hinshaw 1974; 1976].

Figure 20-33: Waldo Hinshaw.

At this time, several research groups in Nottingham worked in parallel on si­mi­lar topics. The first group comprised E. Raymond Andrew, Waldo S. Hinshaw, William S. Moore, Neil Holland, and Paul Bottomley, all of them major con­tri­bu­tors to the development of MR imaging.

In 1977, Waldo Hinshaw, Paul Bottomley, and Neil Holland, succeeded with an image of the wrist [⇒ Hinshaw 1977]. Hinshaw later went to Harvard and then joined the group at the Technicare company, at that time the most ad­van­ced scien­ti­fic group with a commercial and sound me­di­cal applications background.

More human thoracic and abdominal images by different groups and several novel techniques followed, and by 1978, Hugh Clow and Ian R. Young, working at the Bri­tish com­pany EMI, reported the first transverse NMR image through a hu­man head [⇒ Clow 1978].

spaceholder redThe second group in Nottinham included Peter Mans­field (Figure 20-34), Peter K. Grannell, Andrew Maudsley, Ian Pykett, and Peter Morris. They worked on studies of solid periodic objects, such as crystals.

Figure 20-34: Peter Mansfield (1933-2017).

At a Colloque Ampère conference in Cracow, Poland, in September 1973, Mansfield was told about Lauterbur's imaging method after he and his collaborator Peter K. Gran­nell had presented a one-dimensional interferogram of camphor/cardboard samples (Figure 20-35) [⇒ Mansfield 1973].

Figure 20-35:
Model of the one-dimensional lattice (cam­phor with cardboard spacers used for the experiment). Fourier cosine transforms of the transient response to a multiple pulse sequence from the layers of camphor. The result is a linear measurement in a single dimension, not an image.
(a) Three layers, no magnetic field gradient; (b) three layers, gradient of 0.77 G/cm; (c) five layers, same gradient.

For some time in 1974 a third research ‘team’ existed in Nottingham, consisting of Alan N. Garroway (Fi­gu­re 20-36). He applied weak radiofrequency pulses in the pre­sence of a field gradient in order to achieve spatial selectivity. Next door, Peter Mansfield and his post­doc­to­ral students were developing a related method.

Figure 20-36: Alan N. Garroway.

Garroway later joined the Mans­field group. A month before Garroway and Mansfield submitted their first imaging article to Journal of Physics in 1974 they applied to­ge­ther for a first patent [⇒ Garroway 1974]. Un­for­tu­na­tely, their method was un­suit­able for prac­ti­cal application because it suffered from rapid loss of signal; the problem and its solution were explained by David Hoult from Oxford [⇒ Hoult 1977].

By 1975, Mansfield and Andrew A. Maudsley proposed a line tech­ni­que which, in 1977, led to the first image of in vivo human anatomy, a single cross section through a finger. In 1978, using the same single-slice method, Mansfield presented his first image through the abdomen [⇒ Mans­field 1976; 1978].

Figure 20-37: Roger Ordidge.

Echo-planar imaging (EPI), a real-time imaging tech­ni­que, had been proposed by Mansfield's group in 1977, and the first crude images were shown by Mansfield and Ian Pykett in the same year. Roger Ordidge (Figure 20-37) presented the first EPI movie in 1981 [⇒ Ordidge 1981].

The breakthrough of EPI came with manifold improvements in many aspects of the associated methodology and instrumentation — from gradient power supp­ly and gradient coil design to pulse sequence development, presented by Pykett and Rzedzian in 1987 [⇒ Pykett 1987]. However, it remains a niche technology in cli­ni­cal MRI.

spaceholder redThe group around John Mallard at the University of Aberdeen also performed trailblazing research work. James Hutchison, a physicist, Margaret A. Foster, a biologist, and later Bill Edelstein, and their colleagues built their own whole-body MR imag­ing machine and developed the spin-warp technique.

Figure 20-38:
(Top) The first image of a whole mouse was obtained in Aberdeen, Scotland, in March 1974.
(Bottom) The prototype whole-body MR machine in Aberdeen. James Hutchison (1941-2018) lies in the magnet.

They published the first image through the body of a mouse in 1974 which was fol­low­ed by a human whole-body image in 1980 (Figure 20-38) [⇒ Hutchison 1974; ⇒ Edelstein 1980].

spaceholder redIn the 1970s and 1980s Great Britain was a major con­tri­bu­tor to the de­ve­lop­ment of MRI equip­ment and soft­ware, but then a number of the researchers working in Britain went to the United Sta­tes. It was a major brain-drain for British universities, but there was little money in the British university system.

An excellent eyewitness report by some leading British researchers and scientists about the British work was given in the transcripts of a meeting at the Wellcome Institute for the History of Medicine, London, in 1996 [⇒ Christie 1998].

Most of the British researchers stayed abroad, whereas many of the Continental Europeans who worked in the U.S.A. in the late 1970s and early 1980s returned to Europe. Some of the Europeans had performed quite impressive research in the Uni­ted Sta­tes.

spaceholder redAmong them was Robert N. Muller who, in 1982, described off-re­so­nan­ce imag­ing, a technique later dubbed magnetization transfer imag­ing (Figure 20-39) [⇒ Muller 1983]. Peter A. Rinck et al. described the first in vivo fluorine lung images (Figure 20-40) [⇒ Rinck 1984].

Figure 20-39:
Off-resonance images of a knee joint (1982).

Figure 20-40:
19F ventilation imaging of a dog's lung; coronal and transverse images (1982).

Much of the research done at this time was not published, or only presented as abstract in the proceedings of scientific meetings because of the extremely rapid progress in the different research groups.

spaceholder redIn vivo MR Spectroscopy. Actual in vivo NMR spectroscopy took off in Oxford from 1974, with the group of Rex E. Richards and George K. Radda. Among others, David Hoult and David G. Gadian belonged to this group [more details can be found at ⇒ Christie 1998].