Neuroradiology back to the future: head and neck imaging.

SUMMARY: Imaging of the head and neck was initially described within the first year after Roentgen's discovery of the x-ray and was used to localize foreign bodies in the head and neck area, including the orbital, laryngeal, and esophageal regions. Subsequently, x-rays were used to evaluate the air-filled paranasal sinuses, the pneumatized temporal bone, and the upper aerodigestive tract. Special views for evaluating these structures were developed by early investigators. As contrast agents were developed, a variety of invasive procedures were developed to assess the structures of the head and neck. CT and MR imaging were applied to the extracranial head and neck slightly later than the brain and spine; these modalities revolutionized head and neck radiology, finally allowing assessment of the deeper structures of this complex anatomic region.

Neuroradiology back to the future: spine imaging.

Although radiography of the spine began shortly after Roentgen's discovery in 1895, there was little written in the medical literature about spine imaging until nearly 25 years later with the development of myelography, first by using air and then a variety of positive contrast agents. The history of spine imaging before CT and MR imaging is, in large part, a history of the development of contrast agents for intrathecal use. The advent of CT and, more important, MR imaging revolutionized spine imaging. The spinal cord and its surrounding structures could now be noninvasively visualized in great detail. In situations in which myelography is still necessary, advances in contrast agents have made the procedure less painful with fewer side effects. In this historical review, we will trace the evolution of spine imaging that has led to less invasive techniques for the evaluation of the spine and its contents and has resulted in more rapid, more specific diagnosis, therapy, and improved outcomes.

Neuroradiology back to the future: brain imaging.

The beginning of neuroradiology can be traced to the early 1900s with the use of skull radiographs. Ventriculography and pneumoencephalography were introduced in 1918 and 1919, respectively, and carotid angiography, in 1927. Technical advances were made in these procedures during the next 40 years that lead to improved diagnosis of intracranial pathology. Yet, they remained invasive procedures that were often uncomfortable and associated with significant morbidity. The introduction of CT in 1971 revolutionized neuroradiology. Ventriculography and pneumoencephalography were rendered obsolete. The imaging revolution continued with the advent of MR imaging in the early 1980s. Noninvasive angiographic techniques have curtailed the use of conventional angiography, and physiologic imaging gives us a window into the function of the brain. In this historical review, we will trace the origin and evolution of the advances that have led to the quicker, less invasive diagnosis and resulted in more rapid therapy and improved outcomes.

Cerebral blood flow alterations in pain-processing regions of patients with fibromyalgia using perfusion MR imaging.

BACKGROUND AND PURPOSE: Widespread pain sensitivity in patients with FM suggests a CNS processing problem. The purpose of this study was to assess alterations in perfusion as measured by DSC in a number of brain regions implicated in pain processing between patients with FM and healthy controls. MATERIALS AND METHODS: Twenty-one patients with FM and 27 healthy controls underwent conventional MR imaging and DSC. For DSC, 12 regions of interest were placed in brain regions previously implicated in pain processing. rCBF values were calculated for each region of interest. Subjects answered mood/pain coping questionnaires and underwent clinical/experimental pain assessment. RESULTS: There were significant correlations between the thalamic rCBF values and the pain-control beliefs of FM subjects. The strength of the relationship between clinical pain measures and thalamic rCBF values increased after adjusting for pain-control beliefs. There was a significantly different distribution pattern of rCBF values across various brain regions between the FM group and the healthy controls. There was a lower degree of correlation in the FM group between the thalamic rCBF values and the other brain regions relative to the healthy controls. CONCLUSIONS: Significant correlations were found between thalamic rCBF values and pain belief values. These data suggest that there are baseline alterations of brain perfusion in patients with FM. rCBF values of the thalami exhibited lower correlations with respect to other brain regions thought to be involved in pain processing compared with those in healthy controls.

Development of a protocol for coronal reconstruction of the maxillofacial region from axial helical CT data.

Using a fresh frozen cadaver head, a series of axial helical CT scans were obtained using varying imaging parameters both before and after traumatizing the head. The appearance of reformatted coronal images was optimized for the lowest radiation dose. A protocol for imaging the maxillofacial region was developed that produced diagnostic coronal reconstructed images from the axial helical CT data.

MRA in cerebrovascular disease.

Stroke is a major cause of disability and death each year in the United States. Most cases result from atherosclerotic disease at the carotid bifurcations. The risk of such events can be reduced by carotid endarterectomy in both symptomatic and asymptomatic patients with severe occlusive disease documented by imaging studies. A noninvasive means of determining the degree of stenosis is desirable due to morbidity, mortality, and cost associated with catheter angiography. At the present time the main role of MRA is as a screening test to determine who should undergo catheter angiography.

Magnetic resonance imaging of massive bone allografts with histologic correlation.

OBJECTIVE: The objective of this study was to better understand the MRI appearance of massive bone allografts. DESIGN: The MRI findings of three massive bone allografts imaged in vivo were correlated with the histologic findings following removal of the allografts. A fourth allograft, never implanted, was imaged and evaluated histologically. PATIENTS: Allografts were placed for the treatment of primary or recurrent osteosarcoma. RESULTS AND CONCLUSIONS: The in-vivo allografts have a heterogeneous appearance on MRI which we attribute to the revascularization process. Fibrovascular connective tissue grows into the graft in a patchy, focal fashion, down the medullary canal from the graft-host junction and adjacent of the periosteum. The marrow spacers are initially devoid of normal cellular elements and occupied by fat and gelatinous material. This normal postoperative appearance of massive bone allografts must be interpreted as recurrent neoplasm or infection in the allograft. Recognition of these complications rests on features outside the marrow.

MR imaging appearance of intraperitoneal gelatin sponge in mice.

Intraperitoneal gelatin sponge can mimic a mass lesion on magnetic resonance (MR) images. To determine the MR imaging characteristics of gelatin sponge over time, a 15 x 10 x 4-mm piece of gelatin sponge soaked in saline was surgically implanted in the peritoneal cavity of 14 mice. Two mice underwent a sham operation. Contiguous axial spin-echo images of the abdomen were obtained with T1-weighted, spin-density, and T2-weighted sequences preoperatively and over a 6-week period postoperatively. Gelatin sponge initially appears as a heterogeneous mass of low signal intensity on T1-weighted images and increasing intensity on spin-density and T2-weighted images, containing multiple round foci of very low signal intensity, attributable to air, at all sequences. Over time, signal intensity further increases and becomes more homogeneous on spin-density and T2-weighted images, although foci of air persist to 3 weeks. By 2-4 weeks, the mass is no longer discrete. Foci of air should help differentiate gelatin sponge from tumor and add gelatin sponge to the differential diagnosis of abscess.