Neither conventional nor single fibre EMG can be used in isolation from other diagnostic techniques. The motor unit has a restricted repertoire of res- ponse to disease, and different disorders may over- lap in the abnormalities of EMG activity which they present. SFEMG methods may not, therefore, revolutionize diagnosis, but in areas such as the assessment of reinnervation and of the stability of

neuromuscular function they can add precision to diagnosis and prognosis. This book gives an excellent account of them and should be added to medical libraries and to the personal libraries of those interested in the electrical behaviour of muscle in health or disease.

S. Salmons

NON-INVASIVE CARDIOVASCULAR MEASUREMENTS Edit.: H. A. Miller, E. V. Schmidt and D. C. Harrison

Society of Photo-Optical Instrumentation Engineers, $30

Probably nothing is more fundamental to the under- standing of human physiology than a knowledge of the function of the heart. The last decade has wit- nessed many significant steps made towards an understanding of cardiac function both at rest and in pathological states. More importantly, many of the steps have been made with the aid of instruments and techniques developed for the non-invasive assessment of cardiovascular function. This current book, which is based on a conference held in Stan- ford University in 1978, describes some of these steps.

The best established methods of assessing cardio- vascular function are probably those based on radiographic techniques. Advances have now been made in applying computers to the quantitation of coronary artery angiograms for the automatic mea- surement of coronary artery stenosis. Computers have also been applied to the field of positron emission tomography. This is a promising method for assessing the integrity of the myocardium, by mapping the biological processes which are taking place. Unfortunately its use, at least in the short term, will be limited by the need for a nearby cyc- lotron to produce the short lived positron emitting radionuclides.

In the field of intravenous angiography the next few years can anticipate the clinical application of new methods for ventriculography, aortography and for screening patients with extracranial carotid artery and peripheral vascular disease. Some of these developments are described and this section of the book concludes with a chapter on a digital video subtraction system for visualisation of arterial structures following intravenous contrast injection.

A large section of the book is devoted to ultrasono- graphy. In the field of echocardiography increas- ingly widespread use of ultrasonic imaging systems, which are unexcelled in their ability to capture the real time behaviour of the heart, may be anticipated.

Other contributions are concerned with the mea- surement of scattering properties, attentuation, acoustic velocity and acoustic impedence of various tissues. These offer diagnostic possibilities which are only now becoming fully appreciated.

In the field of blood flow measurement, most current developments are limited to the identifica- tion and utilisation of qualititive flow analysis, which can be demonstrated to be clinically useful. As yet little progress has been made towards pre- cise quantitation, but this book outlines several of the steps being made towards improved quantita- tion both of vessel geometry and blood velocity.

The last major section of the book is devoted to magneto-cardiography. The development of this field has been considerably advanced with the deve- lopment of superconducting SQUID magneto- meters and superconducting circuitry capable of measuring small magnetic gradients, in the presence of a large background field. Work is reported on the recording of the magnetocardiogram of the human heart and signals have been observed which appear to arise from His bundle activity. The task for the future will be the development of the magneto- cardiogram in conjunction with the electrocardiogram

My initial reaction to this book was unfavourable. Another conference proceedings, restructured slightly to appear like a book. Inevitably some con- tributions are very much better than others. How- ever, like most conference proceedings, the book presents the current state of the art and will be out of date in another two years. Few, if any, of the contributions will stand the test of time and be con- sidered as benchmark papers. Perhaps realising this, the publishers have opted for a paperback unsewn presentation. I think they were right. This book is an interesting addition to the bookshelf, but not a compulsive buy.

Colin Roberts

J. Biomed. Engng. 1980, Vol. 2, April 155