Thuomas Ka

Degenerative changes following anterior cervical discectomy and fusion evaluated by fast spin-echo MR imaging.

Purpose: To review pre- and postoperative fast spin-echo (FSE) MR images of disc herniation and spondylosis in patients after spinal cervical surgery. Material and Methods: Data were reviewed of 68 patients after anterior discectomy and fusion (ADF) operations using the Cloward technique with solid single level (C5–C6 or C6–C7) or 2-level fusions (C5–C7). The average interval from surgery to review was 37 months. Age- and sex-matched controls without neck problems were examined. Results: Preoperatively, the fusion groups had a higher incidence of protruded disc, and anterior and posterior osteophytes at the levels to be fused than the controls. Postoperatively, there was a significantly higher incidence of posterior osteophytes at the fused levels compared with the controls. Furthermore, the disc herniations and anterior osteophytes at the levels above and below the operated segments were more frequent in the fusion group. Conclusion: ADF causes acceleration of the degenerative changes at the fused level and at the levels below and above the fused segments.

Progressive Brain Compression Changes in Vital Physiological Variables, Correlated with Brain Tissue Water Content and Brain Tissue Displacement. Experimental MR Imaging in Dogs

Continuous recording of vital physiological variables and sequential MR imaging were performed simultaneously during continuous expansion of an epidural rubber balloon over the left hemisphere in anaesthetised dogs. Balloon expansion led to a progressive and slightly nonlinear rise in intracranial CSF pressures and a fall in local perfusion pressures. Changes in systemic arterial pressure, pulse rate, and respiration rate usually appeared at a balloon volume of 4% to 5% of the intracranial volume (reaction volume), together with a marked transtentorial pressure gradient and MR imaging changes consistent with tentorial herniation. Respiratory arrest occurred at a balloon volume of approximately 10% of the intracranial volume (apnoea volume), which was associated with occlusion of the cisterna magna, consistent with some degree of foramen magnum herniation. Increase in tissue water was observed beginning at approximately the reaction volume, presumably due to ischaemic oedema, due to the fall in perfusion pressures.

Fast Spin-Echo MR Assessment of Patients with Poor Outcome Following Spinal Cervical Surgery

PURPOSE The aim of the investigation was to evaluate poor outcome following spinal and cervical surgery. MATERIAL AND METHODS A total of 146 consecutive patients operated with anterior discectomy and fusion (ADF) with the Cloward technique were investigated. Clinical notes, plain radiography, CT, and fast spin-echo (FSE) images were retrospectively evaluated. RESULTS Some 30% of the patients had unsatisfactory clinical results within 12 months after surgery; 13% had initial improvement followed by deterioration of the preoperative symptoms, while 14.4% were not improved or worsened. Disc herniation and bony stenosis above, below, or at the fused level were the most common findings. In 45% of patients, surgery failed to decompress the spinal canal. In only 4 patients was no cause of remaining myelopathy and/or radiculopathy found. FSE demonstrated a large variety of pathological findings in the patients with poor clinical outcome after ADF. Postoperatively, patients with good clinical outcome had a lower incidence of pathological changes. CONCLUSION FSE is considered the primary imaging modality for the cervical spine. However, CT is a useful complement in the axial projection to visualize bone changes.

MR imaging of experimental subdural bleeding : Correlates of brain deformation and tissue water content, and changes in vital physiological parameters

Purpose: To evaluate morphological and physiological changes during acute lethal subdural bleeding in 2 models of anaesthetized dogs. Material and Methods: In model I, blood from the aorta was led into a collapsed subdural rubber balloon while in model II, the blood was directed into the subdural compartment over the left cerebral frontoparietal lobe. Eight vital physiological parameters were continuously registered. MR imaging visualized the compression and displacement of cerebral tissue, and assessed the dynamic changes in cerebral tissue water. Results: In model I, tissue herniation and compression of cerebral ventricles led to death at a haematoma volume corresponding to 8% of the intracranial volume. In model II, the extravasated blood progressed infratentorially and into the spinal sac with a volume that was 3 times larger than that of the lethal haematoma. Tissue water increased almost linearly during bleeding in both models. Conclusion: The high level of mortality after acute subdural haematoma is caused by a reduction in intracranial volume tolerance with a critical decrease in cerebral perfusion pressure, resulting in a fatal cerebral ischaemia.

Retraction of publication

Retracted: Pathophysiology of Metabolic Syndrome The Editor of the electronic Journal of the International Federation of Clinical Chemistry and Laboratory Medicine (eJIFCC) has retracted the article “Pathophysiology of Metabolic Syndrome” by Aganović and Dušek, which was published in eJIFCC. 2007 Feb 26;18(1):3-6 [1]. Upon notice from a reader, based on similarity index analysis, it was found that more than half the text is a copy of a previously published paper by Eckel et al [2].

Book Review: MRI: Principles and ArtifactsMRI: Principles and Artifacts. (Part of the Raven MRI Teaching File.) Edited by HendrickR. E., RussP. D. & SimonJ. H.. 304 pages. ISBN 0-88167-709-4. Raven Press, New York1993. Price: USD 88.50.

This years Nuclear Medicine Annual provides a number of well updated, clearly written reviews describing recent advantages on a number of different subjects within the interesting field of nuclear medicine. The articles are well illustrated and they all provide extensive current reference lists. But none of the articles contains any short summary that could be of importance for providing a quick introduction to a subject the reader may not be so familiar with. The book can be recommended both to physicians working within the area of nuclear medicine, and to those interested in the various topics, even if not especially interested in nuclear medicine. The first chapter givesan updated review of radio labeled antibodies and their potential use in colorectal adenocarcinomas and ovarian carcinomas. This chapter is critical about other imaging techniques including CT and MR imaging whereas it describes immune scintigraphy in an uncritical way. All theoretical advantages and possibilities with that technique are described as if they were already clinically shown to be true, and no limitations of the technique are discussed. The clinical utility of the technique, which has theoretically been promising for decades but has not yet found its proper role, will probably benefit from constructive criticism rather than from too much enthusiasm. SPECT perfusion brain scan findings in a number of dementias, including Alzheimers disease, are well described, and the results are compared and complemented with those seen with other imaging techniques in a balanced way. The tremendous developments of the imaging techniques allowing evaluation of various infections are well described, and there are extensive chapters about the diagnostic applications of radioaerosols in the evaluation of pulmonary diseases and the advantages and disadvantages of myocardial perfusion imaging. The possible benefit that patients with AIDS can derive from nuclear medicine imaging are provided in the chapter about nuclear medicine in HIV-related diseases, which also gives a short but good overview of the epidemiology, pathogenesis and virology of the diseases. There is also a section about the use of other radiologic techniques in the diagnosis of AIDS and AIDS-related complications. The book ends with 2 shorter chapters, the first about divideddose administration of 1 for thyroid remnant ablation after surgery for thyroid cancer. The recommendations given are clear, and although as yet of more importance for the U.S. medical system, they may find applicability with decreasing economy in many other countries. Consequently, this chapter uses mCi instead of MBq, reflecting that it is written for an American audience. The last chapter is a very interesting description of the adrenergic nervous system of the heart as revealed by scintigraphic methods.