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PubMed1979

Clinical indicators of left main coronary artery disease in unstable angina.

Two hundred consecutive catheterized patients with unstable angina pectoris were reviewed to find clinical and noninvasive indicators of left main coronary artery disease (greater than or equal to 50% lesion). Thirty-five patients (17.5% of total) had left main coronary artery disease. There were no differences between patients with and without left main coronary artery disease in age, sex, results of resting electrocardiogram, congestive heart failure, dyspnea during pain, duration of longest pain, arrhythmias, response to medical therapy, or other risk factors. Crescendo angina pectoris (worsening of pre-existing angina), transient ST-segment depression with pain, simultaneous anterior and inferior ST changes during pain, and fluoroscopic calcification of the left main coronary artery were all significantly more common in patients with left main coronary artery disease. However, low sensitivity or low predictive value, or both, limit the usefulness of these clinical predictors. Left main coronary artery disease cannot be reliably predicted in patients with unstable angina pectoris before coronary arteriography.

Angina Pectoris↗
PubMed1986

New approaches to the diagnosis and treatment of venous obstruction.

Diagnosis of chronic venous obstruction has hitherto depended on phlebographic assessment alone. The pitfalls in this method are noted and two simple hemodynamic techniques for measurement of venous obstruction are described. The techniques are easily performed, have a high degree of sensitivity and specificity, and are particularly useful in assessing various therapeutic approaches to venous obstruction. Our experience with a variety of surgical procedures for venous obstruction is described. Two such new procedures, primary arteriovenous fistula and perforator bypass for peripheral venous obstruction, are described in detail.

Adult↗
PubMed2002

Intravascular ultrasound scan evaluation of the obstructed vein.

PURPOSE: The purpose of this study was the comparison of intravascular ultrasound scanning (IVUS) with transfemoral venography in the assessment of chronic iliac vein obstruction. METHODS: IVUS and standard, single-plane, transfemoral venography were performed in 304 consecutive limbs during balloon dilation and stenting of an obstructed iliac venous segment. The appearance of the obstruction was described, and the degree of stenosis (maximal diameter reduction) was estimated with venography and IVUS. The stenotic area was derived with diameter calculations (pir(2)) and also was measured with the built-in software of the IVUS apparatus before and after dilation and stenting in 173 limbs. Preoperative hand/foot differential pressure and preoperative dorsal foot venous and intraoperative transfemoral hyperemia-induced pressure elevations after intra-arterial injection of papaverine hydrochloride were measured. RESULTS: With IVUS, fine intraluminal and mural details were detected (eg, trabeculation, frozen valves, mural thickness, and outside compression) that were not seen with venography. The median stenosis (with diameter reduction) on venographic results was 50% (range, 0 to 100%) and on IVUS results was 80% (range, 25% to 100%). In a comparison with IVUS as the standard, venography had poor sensitivity (45%) and negative predictive value (49%) in the detection of a venous area stenosis of >70%. The actual stenotic area was more severe when measured directly with IVUS (0.31 cm(2); range, 0 to 1.68 cm(2)) versus derived (0.36 cm(2); range, 0 to 3.08 cm(2); P <.001), probably as a result of the noncircular lumen geometry of the stenosis. No correlation was found between any of the preoperative or intraoperative pressure measurements and degree of stenosis with or without collaterals. When collaterals were present, a more severe stenosis (median, 85%; range, 25% to 100%) was observed (versus a 70% stenosis in the absence of collaterals; range, 30% to 99%; P <.001), along with actual stenotic area (with collaterals: median, 0.24 cm(2); range, 0 to 1.18 cm(2); without collaterals: median, 0.45 cm(2); range, 0.02 to 1.68 cm(2); P <.01) and a higher rate of hyperemia-induced pressure gradient (> or =2 mm Hg; with collaterals, 34%; without collaterals, 11%; P <.05). CONCLUSION: Venous IVUS appears to be superior to single-plane venography for the morphologic diagnosis of iliac venous outflow obstruction and is an invaluable assistance in the accurate placement of venous stents after venoplasty. No preoperative or intraoperative pressure test appears to adequately measure the hemodynamic significance of the stenosis. In lieu of adequate hemodynamic tests, IVUS determination of morphologically significant stenosis appears to be presently the best available method for the diagnosis of clinically important chronic iliac vein obstruction. Collateral formation should perhaps be looked on as an indicator of a more severe stenosis, although significant obstruction may exist with no collateral formation.

Angioplasty, Balloon↗
PubMed2001

Orthotopic intestinal transplantation using the cuff method in rats: a histopathological evaluation of the anastomosis.

Segmental small intestine transplantation (SIT) in rats, using a cuff technique, has achieved a high success rate. However, there have been few reports on the influence of the foreign body reaction to polyethylene cuff on vessel anastomoses and graft after SIT. This study involves the histopathological examination of the site of cuff anastomosis and grafts in the short- and long-term survival of segmental SIT. The data obtained from the suture anastomosis model also served as a control. One week after heterotopic segmental SIT using the cuff technique, orthotopic continuations were carried out in syngeneic combination. Twenty-five of 30 rats surviving >200 days (83.3%) were examined for vessel anastomosis. All arterial anastomoses were patent, but the portovenous anastomoses in 10 grafts (33%) were totally occluded and were associated with the formation of collateral vessels. Histopathological examination demonstrated good patency of the artery and vein anastomotic site in the short term, but granulation, fibrosis, and neovascularization at the anastomosis site surrounding the cuffs in the long-surviving group. However, the grafts appeared to be intact, with normal features of the villi. On the contrary, the site of the sutured anastomosis in the long-survival rats showed no inflammatory reaction. Although a polyethylene cuff caused foreign body reaction, the graft blood supplies were maintained by collateral vessels. Considering the low mortality and high success rate, polyethylene cuff is good for short-term study and an alternative method for long-term SIT experiments.

Anastomosis, Surgical↗
PubMed1998

Preoperative identification of viable myocardium: effectiveness of nitroglycerine-induced changes in myocardial Sestamibi uptake.

In order to predict tissue viability in infarcted myocardial areas, changes induced by nitroglycerine infusion on Sestamibi myocardial uptake were evaluated in 37 patients with previously confirmed myocardial infarction undergoing coronary artery bypass grafting, and compared with echocardiographic and perfusional changes occurring after the operation. The improvement of Sestamibi uptake after nitroglycerine correctly classified 24/26 (92%) patients showing postoperative improvement of wall motion in the infarcted area, whereas 24/31 (77%) patients with nitroglycerine-induced increase in Sestamibi uptake had improved wall motion after operation. The presence of collateral flow to the infarcted area was associated with a significantly (P < 0.01) higher increase in Sestamibi uptake both during nitroglycerine infusion and postoperatively. An increase in wall motion score after operation was associated with a significantly higher (P < 0.05) increase in Sestamibi uptake score during nitroglycerine infusion. Thus, the results of this study suggest that Sestamibi perfusional myocardial scintigraphy during nitroglycerine infusion is capable of assessing viable but chronically hypoperfused myocardium and predicting postoperative wall motion and perfusional improvement, to yield the best results in patients with evidence of collateral circulation that supplies the infarcted area.

Aged↗
PubMed1995

[Lateral upper arm flap: topographic-anatomic study for clinical use as vascular pedicled transplant].

Defects of the laryngopharynx and the oral cavity after cancer ablation are increasingly reconstructed by free microvascular anastomosed tissue transfer. Besides the jejunum transplant, we use the free radial forearm flap frequently. This flap is suitable for restoring intraoral and pharyngeal integrity. Major disadvantages are the requirement of a skin graft to obtain wound closure and the cosmetic deformity. The lateral upper arm free flap is intended as alternative method for the fasciocutaneous tissue transfer. Based on our dissection of ten cadavers we demonstrate the anatomy of the flap, the harvesting technique, and present data of vascular pedicle length, vessel calibers, and flap size. The vessel calibers of the profund brachial artery (mean = 2.5 mm) and its terminal branch, the posterior radial collateral artery (mean = 1.8 mm), are comparable to the radial artery. The pedicle length can be extended up to 13 cm by using a lateral approach. The subcutaneous tissue volume was 1.3 cm in average, and compared to the radial flap rather thick. Because of its bulky and strong fascia, the lateral arm flap seems to be useful as a fasciafat flap in facial augmentation and as a fascia flap in soft tissue reconstruction. Disadvantageous are the difficult dissection technique and the loss of sensitivity on the lateral aspect of the forearm. Where a fasciocutaneous flap is indicated, we prefer the radial forearm flap.

Arm↗
PubMedDate not supplied

Gradient echo MRI of portal vein thrombosis.

The MR appearance of thrombosis of the portal vein and its branches using gradient echo (GRE) sequences is described. The study consists of two separate parts. In the first part, five normal volunteers were examined to select the optimal section plane for each portal vessel to be studied. Given the "time of flight" effect of GRE sequences, a scan plane perpendicular to the direction of flow was used to obtain maximal signal enhancement of flowing blood. In the second part of the study, 13 patients with thrombosis of the portal system diagnosed by Doppler sonography, CT, and digital subtraction angiography were examined with the GRE technique. Gradient echo MR confirmed the presence and defined the extent of vessel thrombosis with high diagnostic accuracy. In addition, it proved accurate in detecting portosystemic collaterals. We concluded that the GRE technique can be effectively used as a complement to conventional SE MR to further delineate portal vessels.

Adult↗
PubMed2004

[Transforming and transmitting auditory information].

A mechanism of transforming and transmitting auditory information has been introduced taking into consideration the course of occurrences on molecular level in auditory cell itself. Physical energy of the sound wave is changed into bioelectric energy of the inside of the auditory cell owing to the generated electrochemical gradient. The change of the cell membrane potential which has been caused by the energy of the sound wave influences the change of the calcium level in the cell and at a further stage energetistic processes, enzymatic proteins activity and also it regulates the exocytosis of the mediator. The relationship between the generation of the transmitter and its secretion, and the stimulation of the auditory cell has been discussed. The role of afferent and efferent innervation in the generation of the fast and slow contraction of auditory cells has been noticed. Other phenomena accompanying the process of hearing have also been noticed. They are: Coding information, pre- and post-synaptic inhibition, facilitation of impulse transmission along nervous pathways, collateral inhibition, convergence and divergence. The mechanism of stimulating the receptors in the other senses has been described. A hypothesis has been put forward about the possibility of existence of a mechanism activating ionic canals of the cell membrane of auditory cells other than purely mechanical one connected with tip-links. The mechanism mentioned above may be based on inducing conformational changes of canal proteins, especially potassium canals, by the energy of the sound wave. There is a probability that there exist sound sensitive molecules in the ear as just as there exist light sensitive molecules in the organ of sight. The ability of basement membrane to transmit auditory information, especially on the verge of auditory threshold has been questioned.

Animals↗
PubMed1999

Sensitivity studies of beam directionality, beam size, and neutron spectrum for a fission converter-based epithermal neutron beam for boron neutron capture therapy.

Sensitivity studies of epithermal neutron beam performance in boron neutron capture therapy are presented for realistic neutron beams with varying filter/moderator and collimator/delimiter designs to examine the relative importance of neutron beam spectrum, directionality, and size. Figures of merit for in-air and in-phantom beam performance are calculated via the Monte Carlo technique for different well-optimized designs of a fission converter-based epithermal neutron beam with head phantoms as the irradiation target. It is shown that increasing J/phi, a measure of beam directionality, does not always lead to corresponding monotonic improvements in beam performance. Due to the relatively low significance, for most configurations, of its effect on in-phantom performance and the large intensity losses required to produce beams with very high J/phi, beam directionality should not be considered an important figure of merit in epithermal neutron beam design except in terms of its consequences on patient positioning and collateral dose. Hardening the epithermal beam spectrum, while maintaining the specific fast neutron dose well below the inherent hydrogen capture dose, improves beam penetration and advantage depth and, as a desirable by-product, significantly increases beam intensity. Beam figures of merit are shown to be strongly dependent on beam size relative to target size. Beam designs with J/phi approximately 0.65-0.7, specific fast neutron doses of 2-2.6x10(-13) Gy cm2/n and beam sizes equal to or larger than the size of the head target produced the deepest useful penetration, highest therapeutic ratios, and highest intensities.

Biophysical Phenomena↗
PubMed1989

Electrophysiological characterization of putative C1 adrenergic neurons in the rat.

Recent studies in the rat have demonstrated that at least two populations of sympathoexcitatory reticulospinal neurons reside in the nucleus reticularis rostroventrolateralis. It appears that only one of these populations consists of C1 adrenergic neurons. The present study used both double-labeling (one retrograde tracer and immunohistochemistry) and triple-labeling (two retrograde tracers and immunohistochemistry) to determine if C1 adrenergic neurons, which are immunoreactive for phenylethanolamine N-methyltransferase, exhibit a projection pattern that is sufficiently unique to permit the electrophysiological discrimination between C1 adrenergic and non-adrenergic neurons in the nucleus reticularis rostroventrolateralis. Double-labeling experiments indicated that 71% (range: 53-80) of phenylethanolamine-N-methyltransferase-immunoreactive neurons in the nucleus reticularis rostroventrolateralis could be retrogradely labeled from the thoracic cord, as were 76% (range: 67-94) following tracer injection in the central tegmental tract at pontine levels. Triple-labeling experiments indicated that 88% (range: 82-93) of nucleus reticularis rostroventrolateralis neurons with projections to both spinal cord and central tegmental tract were phenylethanolamine-N-methyltransferase-immunoreactive. Single-unit recording, in nucleus reticularis rostroventrolateralis, was used to identify antidromic potentials elicted from stimulation sites in the spinal cord and/or central tegmental tract. Since clonidine is known to reduce central adrenaline turnover, sensitivity to this drug was used to identify putative adrenergic neurons. Twenty-six nucleus reticularis rostroventrolateralis neurons with axonal projections to both the ipsilateral spinal cord and the central tegmental tract were recorded in halothane-anesthetized rats. All these cells were barosensitive, pulse-modulated, and 16 of the 16 cells tested exhibited a 66 +/- 8% reduction in activity upon the intravenous administration of clonidine (20 micrograms/kg). Most (13 out of 16) exhibited a strong respiratory modulation. The conduction velocity of their spinal collateral was generally low (0.9 +/- 0.1 m/s) and their firing rate moderate (7.4 +/- 1.2 spikes/s). Forty-three nucleus reticularis rostroventrolateralis cells with axonal projections exclusively to the thoracic cord were studied for comparison. These cells were strongly barosensitive and pulse-synchronous, had a high discharge rate (25 +/- 3 spikes/s) and a moderate conduction velocity (3.4 +/- 0.3 m/s). Only one of the 15 cells tested was inhibited by clonidine and only two to these 15 cells exhibited a detectable respiratory modulation. Thus barosensitive nucleus reticularis rostroventrolateralis neurons with axonal projections to both the spinal cord and the central tegmental tract likely belong to the C1 adrenergic cell group. It is concluded that this subgroup of adrenergic neurons probably subserves a vasomotor function.

Action Potentials↗
PubMed1989

Sequential amplification of dihydrofolate reductase and multidrug resistance genes in Chinese hamster ovary cells selected for stepwise resistance to the lipid-soluble antifolate trimetrexate.

We describe the development of resistance to trimetrexate and piritrexim (BW 301U) by a stepwise selection protocol in Chinese hamster ovary cells. Selection in trimetrexate resulted in initial resistance as a result of dihydrofolate reductase gene amplification. Several trimetrexate-resistant variants that display 250-340-fold and 25-50-fold resistance to lipophilic and hydrophilic antifolates, respectively, were established. Increased antifolate resistance was associated with a prominent overexpression of dihydrofolate reductase as determined from the elevated folate reductase activity, cellular labeling with fluorescein-methotrexate, and steady-state mRNA levels as a result of a consistent dihydrofolate reductase gene amplification. However, upon subsequent incremental increases in trimetrexate, further resistance was also associated with amplification of the multidrug resistance gene. This resulted in overexpression of P-glycoprotein and a subsequent 20-50-fold collateral resistance to pleiotropic drugs such as adriamycin, actinomycin D, vinca alkaloids, etoposide, and colchicine. In contrast, initial resistance following selection with low piritrexim concentrations resulted from an unknown mechanism(s) not involving overproduction of either dihydrofolate reductase or P-glycoprotein. This piritrexim resistance was shared with trimetrexate but not with methotrexate. Upon further selection with piritrexim, resistant variants emerge with amplified dihydrofolate reductase but not with multidrug resistance genes. These variants were subsequently resistant to both hydrophilic and lipophilic folate antagonists but retained sensitivity to pleiotropic drugs. The pattern of resistance with methotrexate, trimetrexate, and piritrexim shared a common mechanism, dihydrofolate reductase gene amplification, but differed regarding the additional amplification of the multidrug resistance gene in trimetrexate-resistant cells as well as the emergence of an additional unknown mechanism(s) of resistance to lipid-soluble antifolates upon initial selection in piritrexim.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed2000

A systematic analysis of factors which may impact upon tomographic perfusion imaging measurements: implications for the use of Tc-99m sestamibi in acute myocardial infarction.

BACKGROUND: The use of acute Tc-99m sestamibi imaging has provided a valuable methodology to assess myocardium at risk and collateral blood flow. OBJECTIVE: The purpose of this study was to determine the impact of physical, physiologic, and reconstruction factors on the extent and severity of Tc-99m sestamibi images in a porcine model of coronary occlusion and reperfusion. METHODS AND RESULTS: Eleven pigs underwent 40 min of coronary occlusion using a balloon catheter followed by reperfusion. Radiolabeled microspheres were injected during occlusion for blood flow determination and 20-30 mCi of Tc-99m sestamibi was injected intravenously for cardiac imaging. Each animal underwent four modes of gamma camera imaging: a cardiac and respiratory gated SPECT study, an ungated SPECT study, a post-mortem SPECT study and an ex-situ study where the heart was sliced into five short axis slices and directly imaged. All animals had extensive wall motion abnormalities at the time of imaging. Myocardial risk area by ex-situ imaging was 32 +/- 9% LV and did not significantly change with the addition of a chest cavity and tomographic reconstruction (post-mortem and gated imaging) or cardiac and respiratory motion (ungated imaging). Defect severity was significantly underestimated with the addition of a chest cavity and tomographic reconstruction but was unaltered by cardiac and respiratory motion. CONCLUSIONS: The assessment of risk area acutely by SPECT Tc-99m sestamibi imaging is unaffected by cardiac motion obviating the necessity for gated imaging. Estimated defect severity (which has been used as a measure of collateral flow) is significantly reduced by the chest wall and tomographic acquisition and reconstruction suggesting a role for scatter and attenuation algorithms for this measure.

Animals↗
PubMed1963

Liver disease and ammonia intoxication.

The relation between ammonia intoxication and liver disease is not clear. Ammonia appears to be relatively non-toxic to normal individuals, whereas some patients with liver disease appear to be exquisitely sensitive to dietary protein, ammonia-releasing substances, and ammonium salts. In an attempt to elucidate this relationship the intravenous LD(50) of ammonium chloride was determined in both normal mice and in those with liver disease produced by a variety of means. Parenchymal damage was created by acute and chronic carbon tetrachloride intoxication, a low-protein, lipotrope-deficient diet, and mouse hepatitis virus. Mice in which the portal vein had been partially ligated and those infected with Schistosoma mansoni developed portal-systemic collateral circulation. Groups of these mice were placed on high-protein diets and ammonia drinking water for periods as long as two months. A combination of both parenchymal damage and collateral circulation was induced in mice either by bile duct ligation or by a combination of schistosomiasis and acute carbon tetrachloride intoxication. When the above groups of mice with liver disease were compared with normal control mice in the same weight range, the LD(50) of ammonium chloride showed no striking change.

Ammonia↗
PubMed1998

[Topographic and anatomic study of lateral upper arm transplants].

An anatomic and topographic study of the lateral upper arm free flap for the clinical use in reconstruction. Defects of the laryngopharynx and the oral cavity after cancer ablation are increasingly reconstructed by free microvascular anastomosed tissue transfer. Besides the jejunum transplant we use the free radial forearm flap frequently. This flap is suitable for restoring intraoral and pharyngeal integrity. Major disadvantages are the requirement of a skin graft to obtain wound closure and the cosmetic deformity. The lateral upper arm free flap is intended as alternative method for the fasciocutaneus tissue transfer. Based on our dissection of ten cadavers we demonstrate the anatomy of the flap, the harvesting technique, and present data of vascular pedicle length, vessel calibers, and flap size. The vessel calibers of the profound brachial artery (X = 2.5 mm) and its terminal branch, the posterior radial collateral artery (X = 1.8 mm), are comparable to the radial artery. The pedicle length can be extended up to 13 cm by using a lateral approach. The subcutaneous tissue volume was 1.3 cm in average, and compared to the radial flap rather thick. Because of his bulky and strong fascia the lateral arm flap seems to be useful as a fascia-fat flap in facial augmentation or as a fascia flap in soft tissue reconstruction. Disadvantageous are the difficult dissection technique and the loss of sensitivity on the lateral aspect of the forearm. Where a fasciocutaneous flap is indicated, we prefer the radial forearm flap.

Arm↗
PubMed1986

Bradykinin-induced atropine-sensitive gastric contractions. Activation of an intramural axon reflex?

Gastric motor responses, recorded as volume changes of an intragastric balloon, were induced by the close i.a. administration of bradykinin (0.75-4 micrograms) in chloralose-anaesthetized cats. The animals were vagotomized and the adrenals were ligated at the outset of the experiments. Prior to autonomic blocking agents bradykinin elicited relaxatory or biphasic motor responses. Following nicotinic ganglionic receptor blockade bradykinin caused predominantly gastric contractions. Such excitatory responses were antagonized by 80-100% by atropine, suggesting a dominant neurogenic component. An hypothesis is put forward that the observed gastric contractions result from a bradykinin-induced activation of an axon reflex arrangement confined to thin sensory nerve fibres which, by substance P release from intramural collaterals, excite postganglionic cholinergic motor neurones.

Animals↗
PubMed1987

Actions of MPTP and MPP+ on synaptic transmission in guinea-pig hippocampal slices.

MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine) causes a Parkinson's disease-like syndrome in man, monkeys, and mice. We studied the effects of MPTP and its metabolite, MPP+, on neuronal properties and synaptic transmission in isolated slices of guinea-pig hippocampus using intra- and extracellular recording methods. Addition of MPTP to the superfusate (50 to 100 microM) produced the following effects: Excitatory postsynaptic potentials and extracellularly recorded population spikes, evoked by stimulation of the Schaffer collaterals were increased in amplitude during the application period (30 min). Within 30 min of washing in normal solution, synaptic transmission was blocked, although axonal population action potentials could still be elicited. The block of synaptic transmission was prevented by prior incubation in pargyline, an inhibitor of monoamine oxidase. The membrane potential and resistance of single pyramidal neurons were virtually unaffected; action potentials elicited by depolarizing intracellular current pulses were also unchanged. MPP+ (50 microM) blocked synaptic transmission during the application period by a pargyline-in-sensitive mechanism. These results suggest that MPP+ blocks synaptic transmission in the hippocampus at a presynaptic site. This effect may be relevant for the acute action of MPTP and may provide some insight into its chronic action on nigrostriatal neurons.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗
PubMed1993

Microglial MHC antigen expression after ischemic and kainic acid lesions of the adult rat hippocampus.

By taking advantage of the specific neuronal and connective organization of the hippocampus and the different susceptibility of hippocampal neurons to transient cerebral ischemia or intraventricular injections of kainic acid (KA), we examined the microglial reactions to different types of neuronal injury. In all areas with neuronal or axonal degeneration, the microglial cells reacted by specific degeneration-related morphological transformations and expression of class I major histocompatibility complex (MHC) antigen. Subpopulations of microglial cells also expressed class II MHC antigen and leukocyte common antigen (LCA) in relation to (1) degenerating nerve cell bodies in the dentate hilus and the CA1 and CA3 pyramidal cell layers, (2) postischemic degeneration of dendrites in the stratum radiatum of CA1, and (3) combined dendritic and axonal degeneration in the stratum radiatum of the KA-lesioned CA3. MHC II and LCA expression was not observed in relation to degeneration of the CA3-derived Schaffer collaterals in CA1 after KA-induced CA3 lesions. In the case of ischemia the degeneration-related reactions were preceded by an early, generalized microglial reaction, which also included areas without subsequent signs of neural degeneration. This reaction, which was transient and characterized by subtle morphological changes and induction of class I MHC antigen only, was presumably triggered by a general postischemic perturbation of the cerebral microenvironment, and not by actual neural degeneration. In conclusion, we found that microglial expression of class I MHC antigen was a sensitive marker of both the general perturbation after ischemia and axonal degeneration distant from the areas of actual nerve cell death.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

MRI of the Stener lesion.

OBJECTIVE: To assess the utility of MR in detecting surgically induced Stener lesions (displaced thumb ulnar collateral ligaments) in cadaveric models. DESIGN: Six cadaver thumbs had ulnar collateral ligament (UCL) tears created surgically. MR examinations (2D STIR and 3D GRASS) were performed identically on all specimens both before displacement (non-Stener) and after displacement (Stener lesion) of the UCL. The MR images were then randomly numbered. Each image was evaluated separately in blinded fashion by four musculoskeletal radiologists for the presence or absence of a Stener lesion. Each radiologist reinterpreted the images after an interval of several days. The interpretation was based on previously published criteria for Stener lesion diagnosis by MR. RESULTS: The sensitivity of GRASS ranged from 0.17 to 0.67 with the most experienced reader scoring the lowest. The specificity of GRASS ranged from 0.33 to 1.0 (most experienced reader 0.67, 0.83). STIR had a sensitivity of 0.00-0.17 and a specificity of 0.53-0.83. The kappa values for inter- and intraobserver agreement were measured. The intraobserver kappa for GRASS was 0.27-0.75 (most experienced reader 0.75). CONCLUSIONS: 2D imaging is probably inadequate for the evaluation of Stener lesions. The most likely reason is that the STIR slice thickness of 3 mm limits resolution of small UCLs. The poor sensitivity and specificity of GRASS as well as poor interobserver agreement suggest that MR may not be sufficiently accurate for Stener lesion evaluation.

Humans↗