100 years and running: the medical imaging revolution

Abstract

1995 marks the centenary of Roentgen's discovery of the X-ray. Many of the techniques in use today (eg, computed tomography, [CT]) are only a couple of decades old. Few radiologists can now keep abreast of the entire specialty, so there is increasing technique-based or system-based specialisation. Among the technique-based specialties, CT provides single-breathhold volume imaging with spiral data acquisition; the result is three dimensional and wonderfully clear. The thorax and liver can be visualised rapidly without registration artifacts, and pulmonary emboli identified directly (Radiology 1993; 188: 618). Development of very small catheters and specialised gnidewires, as described by Rees, has allowed interventional radiology techniques to probe further into the vascular system. Schenck et al showed that interventional techniques with open-MRI systems are now possible. Nuclear medicine techniques such as whitecell scintigraphy are replacing barium methods for assessment of inflammatory bowel disease. More specific isotope-receptor labelling is providing increasingly targeted information--eg, in inflammation, as shown by Jamar. Large clinical trials of positron-emission tomography (PET) are proving the ability of this technique to identify small f oc i of tumour and to differentiate recurrent malignancy from fibrosis. Crossfertilisation between PET and single-photon emission tomography (SPET) methods may make these techniques more widely available• Technical advances likewise predominate among the system-based specialties. For gastrointestinal imaging, cross-sectional techniques encroach on barium studies and endoscopy. Magnetic resonance cholangiopancreatography has improved substantially, as Laubenberger showed, and may replace purely diagnostic endoscopic retrograde cholangio-pancreatography procedures. Ultrasound can detect the increased arterial perfusion caused by colorectal hepatic metastases (Radiology 1995; 195:113). MRI and interventional techniques dominate developments in neuroradiology. Interventional procedures carry fewer complications than conventional neurosurgery for aneurysms in the posterior circulation, and some lesions previously deemed inoperable are now amenable to neuroradiological intervention (J Neurol Neurosurg Psychiatry, in press). Tumour imaging has benefited from many of the technical advances; modern CT, as shown by Vinnicombe, has provided better data about normal lymph nodes, and MRI gives new insights in breast imaging, detection of tumour recurrence, and implant complications now being established indications•