Perfusion MRI before and after acetazolamide administration for assessment of cerebrovascular reserve capacity in patients with symptomatic internal carotid artery (ICA) occlusion: comparison with <Superscript>99m</Superscript>Tc-ECD SPECT

Introduction Impaired cerebral vascular reserve (CVR) in patients with symptomatic internal carotid artery (ICA) occlusion is regarded as a possible indication for performing extra-/intracranial (EC/IC) bypass surgery. As perfusion MR imaging (MRI) can demonstrate cerebral haemodynamics at capillary level, our hypothesis was that perfusion MRI could be used in these patients for the evaluation of CVR following acetazolamide challenge in a similar way to single photon emission CT (SPECT) and might provide additional information. Methods Enrolled in the study were 12 patients (mean age 61.3 years; 11 male, 1 female) with symptomatic unilateral ICA occlusion proven by angiography. Both perfusion MRI and 99m-technetium-ethyl-cysteinate dimer (^99mTc-ECD) SPECT were performed before and after injection of acetazolamide (Diamox ,1000 mg i.v.). CVR parameters including regional cerebral blood flow (rCBF) and volume (rCBV), and mean transit times (MTT) were measured by perfusion MRI. Results The patients with impaired CVR proven by SPECT (n = 9) had a negative mean rCBF increment (−46.52%), negative rCBV increment (−13.5%) and delayed MTT (mean +2.98 s), respectively, on the occluded side (Student’s t-test all P < 0.05). The patients with sufficient CVR (n = 3) had a mean rCBF increment of 1.2%, a decrement of rCBV of 10.46%, and a mean MTT shortening of 0.27 s following the acetazolamide injection. Conclusions Perfusion MRI before and after acetazolamide administration compares favourably with ^99mTc-ECD SPECT for the detection of impaired CVR. The impact that perfusion MRI studies (before and after acetazolamide administration) might have on the treatment decision in patients with ICA occlusion has yet to be determined by a prospective study. The first and second author contributed equally to this study.     

An air gun pellet retained in the heart: a case report

We report the rare case of an air gun pellet retained within the myocardium. The pellet passed through the right ventricle and the interventricular septum and was retained in the posterior left ventricular wall. The patient presented with cardiac tamponade requiring urgent surgical treatment. The case report is followed by a review of the pertinent literature.     

Vertical infraclavicular brachial plexus blockade

Brachial plexus blockade is routinously performed by using the axillary route. From clinical experience and anatomical point of view it is known that the axillary approach is not the ideal technique to achieve efficient brachial plexus anesthesia. Regarding the anatomical conditions, it is clear that the mid-retrosubclavian region should be the most appropriate place to apply the local anesthetic agent due to the fact that all three fascicles of the plexus are lying close together. During the past several decades different supra- and infraclavicular approaches have been described but none of them are still in use to a great extent today. Since 1993 we routinely have used the vertical infraclavicular approach, a self developed technique based on detailed anatomic studies. This method of brachial plexus blockade has clearly defined guidelines using simple reproducible landmarks and is performed by applying a strongly vertical puncture at the center line between the ventral apophysis of acromion (lateral landmark) and the jugular notch (medial landmark) directly beneath the clavicula. The patient is lying in a supine position with his forearm relaxed on the chest and his head slightly turned to the contralateral side. The brachial plexus is met in 3 to 4 cm depth. Because of its advantages the vertical infraclavicular blockade has become the most applied technique in upper extremity regional anesthesia in our hospital. The method has a high success rate, low risks, and a high acceptance by both patients and anesthetists. © 2003 Elsevier Inc. All rights reserved.     

Survival and reoperation pattern after 20 years of experience with aortic valve–sparing root replacement in patients with tricuspid and bicuspid valves

Objective

Remodeling or reimplantation are established operative techniques of aortic valve–sparing root replacement. Long-term follow-up is necessary comparing tricuspid and bicuspid aortic valves.

Evaluation of the decellularized pulmonary valve homograft (SynerGraft)

BACKGROUND AND AIM OF THE STUDY: Rejection is thought to contribute to the degeneration of valved homografts. A novel cryopreserved decellularized homograft valve (SynerGraft; CryoLife, Inc.) offers the unique opportunity to gain new insight into the immunology of homograft implantation and its significance for valve function. METHODS: Twenty-four patients (group I; mean age 37 +/- 11 years) underwent implantation of a pulmonary SynerGraft and were examined at one and six months postoperatively; 22 patients (group II; mean age 41 +/- 17 years) with conventional homografts served as controls. Temperature, C-reactive protein (CRP) levels and white blood cell count (WBC) were studied perioperatively. Follow up included echocardiography and anti-human leukocyte antigen (HLA) class I antibody determination. RESULTS: Significantly lower temperatures were measured in group I (p = 0.019). CRP level and WBC each increased postoperatively, but did not differ between groups. During follow up, none of the SynerGraft patients became positive for anti-HLA antibodies, compared with 66% of controls (p = 0.011). Homograft diameter and valve orifice area were decreased significantly at one month after surgery in groups I and II (25 +/- 1 versus 18 +/- 3 mm; 25 +/- 1 versus 19 +/- 2 mm, respectively; p <0.001 both groups). Transvalvular pressure gradients significantly increased during follow up. CONCLUSION: Implantation of the SynerGraft pulmonary homograft appeared safe, and though evidence was found of a reduced immunologic response after SynerGraft implantation this (unexpectedly) did not translate into any hemodynamic advantage. Hence, factors other than rejection appear as the main contributions to the observed functional changes.     

Evidence of a non-motor microlesion effect following deep brain surgery: a case report

We report the case of a patient who developed acute transient psychosis after implantation, but not activation of pallidal deep brain electrodes for generalised dystonia. Psychotic symptoms coincided temporally with postoperative motor improvement induced by the microlesion effect after electode implantation. This finding suggests that the microlesion effect may not be confined to motor improvement, but also comprises non-motor symptoms. In our case, affection of adjacent dopaminergic fibres of passages has to be assumed.