Right-sided Injection Research Articles

Local Injection for Treating Mood Disorders (LIFT-MOOD): A Pilot Feasibility RCT of Stellate Ganglion Block for Treatment-Resistant Depression

Background With nearly one-third of patients with major depressive disorder being resistant to available antidepressants, there is a need to develop new treatments for this population. Stellate ganglion block (SGB) is a procedure used to block sympathetic input to the central autonomic system; it has been administered to treat several conditions, including pain. Recently, indications for SGB have extended and the potential benefits for psychiatric disorders are under investigation. Methods The Local Injection For Treating Mood Disorders (LIFT-MOOD) study investigated the feasibility of a trial of 2 right-sided injections of bupivacaine 0.5% (7 mL) at the stellate ganglion in participants with treatment-resistant depression (TRD) using a randomized, placebo-controlled, pilot trial. Ten participants were randomized in a 1:1 allocation to receive active treatment or placebo (saline). Primary feasibility outcomes included recruitment rate, withdrawal, adherence, missing data, and adverse events. As a secondary, exploratory objective, we explored the efficacy of SGB in improving symptoms of depression by calculating the change in scores from baseline to follow-up on day 42 for each treatment group. Results The recruitment rate was reasonable and sufficient, retention and adherence were high, missing data were low, and adverse events were mild and temporary. Both treatment groups demonstrated decreases in Montgomery-Åsberg Depression Rating Scale scores, compared to baseline, by the end of the study. Conclusion This study supports the feasibility of a confirmatory trial of SGB in participants with TRD. Conclusions regarding efficacy cannot be made based on this preliminary study due to the small number of participants who completed active treatment. Larger-scale randomized controlled trials with long-term follow-ups and alternate sham procedures are needed to assess the efficacy and duration of symptom improvement with the use of SGB in TRD.

Functional lateralization in the prefrontal cortex of dopaminergic modulation of memory consolidation.

There is increasing evidence of functional lateralization within the rat brain. Here, we have examined the lateralization of dopamine (DA) function in the medial prefrontal cortex (PFC) in relation to memory consolidation in the novel object recognition test (NOR). Male Wistar rats received single bilateral or unilateral injections into prelimbic-PFC of agonists (SKF81297; 0.2 µg, quinpirole; 1 µg, SB277,011; 0.5 µg) and antagonists (SCH23390; 3 µg, L-741,626; 1 µg, 7-OH-DPAT; 3 µg) at DA D1, D2, or D3 receptors, immediately following the exposure trial in the NOR, and were tested either 1 or 24 h later for discrimination between a novel and a familiar object. As previously reported, bilateral injection of a D1 antagonist (SCH23390, 3 µg/side), a D2 antagonist (L-741,626, 1 µg/side) or a D3 agonist (7-OH-DPAT, 3 µg/side) impaired NOR at 1 h, while a D1 agonist (SKF81297, 0.2 µg/side), a D2 agonist (quinpirole, 1 µg/side) or a D3 antagonist (SB277,011, 0.5 µg/side) improved NOR at 24 h. The same effects were seen with left-sided unilateral injections. No effects were seen with right-sided unilateral injections. Endogenous DA release in the prelimbic-PFC promotes memory consolidation in the NOR, but only on the left side of the brain.

Driving reaction times in patients with foot and ankle pathology before and after image-guided injection: pain relief without improved function.

Foot and ankle pathology is common in the driving population. Local anesthetic steroid injections are frequent ambulatory treatments. Brake reaction time (BRT) has validated importance in motor vehicle safety. There are no prior studies examining the effect of foot and ankle pathology and injection treatment on the safe operation of motor vehicles. We studied BRT in patients with foot and ankle musculoskeletal disease before and after image-guided injection treatment. A total of 37 participants were enrolled. Image-guided injections of local anesthetic and steroid were placed into the pathological anatomical location of the right or left foot and ankles. A driving reaction timer was used to measure BRTs before and after injection. Patients suffering right "driving" and left "nondriving" pathology as well as a healthy control group were studied. All patients reported >90% pain relief postinjection. All injections were confirmed to be accurate by imaging. Post hoc Bonferonni analysis demonstrated significant difference between the healthy group and the right-sided injection group (P = .008). Mean BRT for healthy controls was 0.57 ± 0.11 s. Patients suffering right foot and ankle disease displayed surprisingly high BRTs (0.80 ± 0.23 s preinjection and 0.78 ± 0.16 s postinjection, P > .99). Left nondriving foot and ankle pathology presented a driving hazard as well (BRT of 0.75 ± 0.12 s preinjection and 0.77 ± 0.12 s postinjection, P > .99). Injections relieved pain but did not significantly alter BRT (P > .99 for all). Patients suffering chronic foot and ankle pathology involving either the driving or nondriving side have impaired BRTs. This preexisting driving impairment has not previously been reported and exceeds recommended cutoff safety values in the United States. Despite symptom improvement, there was no statistically significant change in BRT following image-guided injection in either foot and ankle. Therapeutic, Level II: Prospective Comparative Study.

Telencephalic organization of the olfactory system in homing pigeons (Columba livia)

Pigeons use olfactory cues to navigate over unfamiliar areas, and any impairment of the olfactory system generates remarkable reduction of homing performance. Lesion and deprivation studies suggest a critical involvement of the right nostril and thus, the right olfactory bulb (OB) and the left piriform cortex (CPi) for initial orientation. This functional pattern suggests that OB and CPi are asymmetrically connected with a stronger projection from the right OB to the left CPi. However, the structural organization of the olfactory system is not unequivocally clarified yet. Thus, we re-analyzed the system by antero- and retrograde tract tracing with biotinylated dextran amine and choleratoxin subunit B, and we especially evaluated quantitative differences in the number of cells in the OB innervating the left and right CPi. Our anterograde tracing data verified a strong bilateral input to the CPi, and the prepiriform cortex (CPP), as well as small projections to the ipsilateral medial septum and the dorsolateral corticoid area and the nucleus taeniae of the amygdala in both hemispheres. Apart from the bilateral bulbar afferents, CPi in turn receives unequivocal input from the ipsilateral CPP, hyperpallium densocellulare, dorsal arcopallium, and from a cluster of cells located within the frontolateral nidopallium. Thus, an indirect connection between OB and CPi is only mediated by the CPP. For quantitative analysis of bulbar input to the CPi, we counted the number of ipsi- and contralaterally projecting neurons located in the OB after injections into the left or right CPi. Retrogradely labeled cells were found bilaterally in the OB with a higher number of ipsilaterally located cells. The bilaterality index did not differ after left- or right-sided CPi injections indicating that the functional lateralization of the olfactory system is not simply based on differences in the number of projecting axons of the major processing stream.

Treatment of Debilitating Cremasteric Synkinesia With Intracremasteric Botulinum-A Toxin Injections

To describe the surgical technique of botulinum-A toxin injection into the cremasteric muscles of a 26-year-old male with bilateral cremasteric muscle spasms causing significant pain and limitation of activity. This pain has been refractory to multiple previous therapies, including inguinal nerve blocks and bilateral orchidopexies with cremasteric muscle lysis. Multiple imaging modalities revealed no obvious pathology for this significant bilateral pain. Genitourinary examination revealed hyper-retractile testes with changes consistent with bilateral orchidopexies and was otherwise normal. The patient has undergone 3 outpatient staged injections of botulinum-A toxin into the bilateral cremasteric muscles after spermatic cord block with 1% lidocaine. One hundred units of botulinum-A toxin mixed into 10 mL of sterile normal saline were used for each injection staged 6 weeks apart. The patient tolerated all injections without apparent side effects. After the first injection into his left side, his baseline pain scores were reduced from 8 out of 10 to 3 out of 10 on a standard 10-point pain scale. He reported maximal efficacy 2 weeks after each injection, with dissipation over 4-6 weeks. After 2 left-sided and 1 right-sided injections, his baseline pain was 2 to 4 of 10, equal bilaterally, and he was back to rigorous activity with some limitations. Direct injection of botulinum-A toxin into the cremasteric muscle is a viable treatment option for the rare patient with debilitating and painful cremasteric spasms refractory to other therapies.

Comparison of one-side and bilateral intracavernosal papaverine injection on a Doppler study of the penis

Intracavernosal injection of a vasodilating agent, followed by color Doppler ultrasonography of the penis, is used to diagnose vascular impotence. The vasodilating agent is usually injected into one of the corpora cavernosa and the peak systolic velocity (PSV) of the cavernosal arteries is measured on both sides, presuming that the connection between the two cavernosal bodies will distribute the drug uniformly on both sides and will consequently affect the cavernosal arteries and sinusoids equally. According to our experience, the PSV of the injection side is higher than that of the contralateral side. This difference could affect the results of the evaluation. In this study, our objective was to compare the results of both-side injections with those of one-side injection. A total number of 60 patients with a normal Doppler study of the penis were enrolled in the study and were randomly divided into three groups. In the first and second group, 60 mg papaverine was injected into the right and left corpus cavernosa each. In the third group, half of the dose was injected into each side. The mean maximum PSV was measured and compared in each group. The mean maximum PSV in the group with the right-side injection was 47.7+/-10.8 and 40.3+/-9.2 on the right and left side, respectively. The mean maximum PSV in the group with the left side injection was 44.4+/-7.1 and 51.4+/-7.1 on the right and the left side, respectively. The mean maximum PSV in the group with bilateral injection was 47+/-9.9 on the right side and 46.7+/-10.7 on the left side. In the first two groups, there was significant difference between the mean maximum PSV of the right and left cavernosal arteries, but in the third group, there was no significant difference between the mean maximum PSV of both side cavernosal arteries. Injecting papaverine in only one corpus cavernosum, despite a perfect postinjection manipulation of the penis, will affect the sinusoids and cavernosal artery at the same side of the injection more than the contralateral side. This results in a higher increase in the blood flow and PSV on that side and results in an artifactual difference between the velocity of the right and left side, which could ultimately exaggerate or mask the actual difference between the two sides. Dividing the total dose of the vasodilating agent and injecting half of the dose into each corpus cavernosum separately prevents artifactual difference between blood flow and velocity on the right and left side.

Language assessment in Wada test: Comparison of methohexital and amobarbital

Introduction Methohexital has replaced amobarbital during Wada testing at many centers. The objective of our study was to compare the use of methohexital and amobarbital during Wada testing regarding language and memory lateralization quotients as well as speech arrest times. Methods A chart review of 582 consecutive patients undergoing 1041 Wada-procedures was performed (left = 60, right = 63, bilateral = 459). Language lateralization was calculated based on duration of speech arrest using a laterality index, defined as ( L − R)/( L + R). Memory lateralization was expressed as percentage of retained objects and laterality quotient. Results Language and memory lateralization revealed a similar distribution with amobarbital and methohexital. Speech arrest after left and right-sided injection was significantly longer in the amobarbital group as compared to the methohexital group. Language lateralization did not differ in the two groups. Percentage of retained memory items was higher in the methohexital group and there were fewer presented test items in the methohexital group. Discussion Language and memory testing during the Wada test can successfully be performed with methohexital instead of amobarbital. The shorter half-life of methohexital allows repeated injections and shorter interhemispheric testing intervals, but also shortens the testing window.

Hemisphere-specific Episodic Memory Networks in the Human Brain: A Correlation Study between Intracarotid Amobarbital Test and [18F]FDG-PET

Abstract The purpose of the present study was to explore the brain regions involved in human episodic memory by correlating unilateral memory performance estimated by the intracarotid amobarbital test (IAT) and interictal cerebral metabolism measured by [18F]fluorodeoxyglucose positron emission tomography ([18F]FDG-PET). Using this method, regional alterations of cerebral metabolism associated with epilepsy pathophysiology are used to predict hemisphere-specific episodic memory function, hence, investigate the differential distribution of memory in each hemisphere. Sixty-two patients with unilateral temporal lobe epilepsy (35 left and 27 right) were studied using [18F]FDG-PET with complementary voxel-based statistical parametric mapping (SPM) and region-of-interest (ROI) methods of analysis. Positive regression was analyzed in SPM with a series of different thresholds (p = .001, .01 or .05) with a correction to 100 voxels. IAT memory performance in which left hemisphere was tested by right-sided injection of amobarbital correlated with [18F]FDG uptake in left lateral and medial temporal regions, and in the left ventrolateral frontal cortex. Right IAT memory performance correlated with [18F]FDG uptake in the right inferior parietal lobule, right dorsolateral frontal cortex, right precentral gyrus, and caudal portion of the right anterior cingulate cortex. ROI analysis corroborated these results. Analyses carried out separately in patients with left (n = 50) and nonleft (n = 12) dominance for language showed that in the nonleft dominant group, right IAT scores correlated with right fronto-temporal regions, whereas left total memory scores correlated with left lateral and medial temporal regions. The findings indicate that (i) episodic memory is subserved by more widespread cortical regions beyond the core mesiotemporal lobe memory structures; (ii) there are different networks functional in the two hemispheres; and (iii) areas involved in memory may be different between patients with left and nonleft dominance for language, particularly in the right hemisphere.

Subtilisin-like proprotein convertase activity is necessary for left–right axis determination in Xenopus neurula embryos

Signaling by members of TGF-beta superfamily requires the activity of a family of site-specific endopeptidases, known as Subtilisin-like proprotein convertases (SPCs), which cleave these ligands into mature, active forms. To explore the role of SPCs in lateral plate mesoderm (LPM) differentiation in Xenopus, two SPC inhibitors, decanoyl-Arg-Val-Lys-Arg-chloromethylketone (Dec-RVKR-CMK) and hexa-arginine, were injected into the left and right LPM of Xenopus neurulae. Left-side injection caused heart-specific left-right reversal, and this phenotype was rescued by co-injection of mature Nodal protein. In contrast, right-side injection caused left-right reversal of both the heart and gut. Tailbud embryos were less sensitive to SPC inhibitors than neurula embryos. Injection of inhibitors into either side of neurula embryos completely abolished expression of the left-LPM-specific genes, Xnr-1, antivin, and pitx2. SPC1 enzyme (Furin) was injected into the left or right LPM of mid-neurula embryos to determine the effect of enhancing SPC activity. Left-side injection of SPC1 did not cause a significant left-right reversal of the internal organs. However, right-side injection of SPC1 strongly induced the expression of Xnr-1 and pitx2 in the right LPM, and caused 100% left-right reversal of both the heart and gut. These results suggest that moderate level of SPC activity in the right LPM of the neurulae is necessary for proper left-right specification. Taken together, SPC enzymatic activity must be present in both LPMs for expression of the left-handed genes and left-right axis determination of the heart and gut in Xenopus embryos.

Xenopus nodal related-1 is indispensable only for left-right axis determination

In Xenopus, multiple nodal-related genes are expressed in the organizer region. Among them, only Xenopus nodal related-1 (Xnr-1) is expressed unilaterally in the left lateral plate mesoderm (LPM) at late neurula-early tailbud stage. To elucidate the essential role of Xnr-1 for left-right specification, loss of function experiments using antisense morpholino oligonucleotides (MOs) targeting three different regions of Xnr-1 were performed. Left-side injection of Xnr-1 MO suppresses the left-side specific genes such as Xnr-1, Xenopus antivin (lefty) and Xenopus pitx2 and randomizes cardiac and visceral left-right orientation. In contrast, paraxial bilateral expression of Xnr-1 along the posterior notochord is not affected by the Xnr-1 MO. In embryos injected with the Xnr-1 MO, morphology of dorsal axial structures is normal and dorsal expression of sonic hedgehog and TGF-beta5 is not changed. Right-side injection of Nodal protein, or polyethyleneimine-based gene transfer of Xnr-1 mRNA in the right LPM induces Xnr-1 and pitx2 in the same side and fully (more than 90%) reverses situs of the internal organs. Left-side injection of Nodal protein restores normal left-right orientation in the embryos that were injected with Xnr-1 MO into the left blastomere and would cause randomization of the left-right axis without the Nodal injection. Taken together, unilateral expression of Xnr-1 in the left LPM directs the orientation of the left-right axis by driving the left-specific gene cascade. Knockdown of Xnr-1 function by the MOs suggests that Xnr-1 is indispensable only for the left-right orientation and dispensable for other embryonic axes probably owing to the redundancy in the function of multiple Xnrs.

Xenopus neurula left-right asymmetry is respeficied by microinjecting TGF-beta5 protein.

A variety of TGF-beta-related ligands regulate the left-right asymmetry of vertebrates but the involvement of TGF-betas in left-right specification has not been reported. We assessed whether TGF-beta signaling is involved in the left-right specification of Xenopus post-gastrula embryos by microinjecting Xenopus TGF-beta5 protein into the left or right flank of neurula-tailbud embryos. Injection on the right side of neurulae caused left-right reversal of the internal organs in 93% of the embryos, while injection on the left side caused less than 5% left-right reversal. Expression of Xenopus nodal related-1 (Xnr-1 ), Xenopus antivin and Xenopus Pitx2, which are normally expressed on the left, was unaltered by the left-side injection. In contrast, right-side injection into neurulae induced the expression of these genes predominantly on the right side. Right-side injection into tailbud embryos caused bilateral expression of these handed genes. Time course analysis of asymmetric gene expression revealed that Xnr-1 could be induced by TGF-beta5 at late neurula stage, while antivin and Pitx2 could be induced by TGF-beta5 at the latertail bud stage. Injection of the antisense morpholino oligonucleotide against Xenopus TGF-beta5 into the left dorsal blastomere inhibited the normal left-handed expression of Xnr-1 and Pitx2, and caused the organ reversal in the injected embryos. These results suggest that normal left-right balance of endogenous TGF-beta5 signaling in the neurula embryo may be needed to determine the laterality of the asymmetric genes and to generate the correct left-right axis.

Helical CT evaluation of the perirenal space and its boundaries: a cadaveric study.

To determine whether the perirenal spaces communicate across the midline and with the pelvic extraperitoneal spaces. Helical CT was used to guide the sequential injection of 100-mL intravenous boluses of dilute contrast medium, up to 300 mL, into the perirenal space of eight embalmed cadavers (three male, five female; mean age at death, 82 years; range, 72-93 years), with four left-sided and four right-sided injections. All images were acquired after the final injection (300 mL total) to facilitate coronal and sagittal reconstruction of relevant images. All images were reviewed to assess the flow pathways of contrast medium from the perirenal space to other retroperitoneal spaces. In three cadavers that received left perirenal space injections and in two cadavers that received right perirenal space injections, communication was seen with the contralateral perirenal space through an area anterior to the aorta and inferior vena cava. In three cadavers that received right perirenal space injections, contrast material flowed from the right perirenal space to outline the bare area of the liver. Communication between the perirenal and pelvic extraperitoneal spaces was seen in all eight cadavers; contrast material extended into the pelvic extraperitoneal and presacral spaces. These findings show that the perirenal spaces communicate with each other across the midline and with the pelvic extraperitoneal spaces. Clinical implications are that perinephric collections can potentially flow into the pelvis or across the midline.

More Than 95% Reversal of Left–Right Axis Induced by Right-Sided Hypodermic Microinjection of Activin into Xenopus Neurula Embryos

In recent years, genes that show left–right (L-R) asymmetric expression patterns have been identified one after another in vertebrate gastrula–neurula embryos. However, we still have little information about when the irreversible L-R specification is established in vertebrate embryos. In this report, we show that almost 100% of the embryos develop to be L-R-inverted larvae after microinjection of activin molecules into the right lateral hypodermic space of Xenopus neurula embryos. After right-side injection of 10–250 pg activin protein, both early neurulae just after gastrulation movement (stage 13–14) and late neurulae just before neural tube closure (stage 17–18) showed almost 100% reversal of the heart and gut L-R axes. At higher doses of activin, more than 90% of the L-R-inverted embryos showed L-R reversal of both heart and gut. The survival ratio of the right-injected 4-day embryos was 90% on average. In the left-injected embryos, the occurrence of L-R inversion was less than 2% as observed in normal untreated siblings (1.7%). When the same amount of activin (1–50 pg) was microinjected into both sides of neurula embryos, the incidence of L-R inversion was reduced to 58%. The injection of activin along the dorsal midline in the trunk region also randomized the visceral L-R axis. Injection of activin into the right side changed normal left-handed expression of Xnr-1 to right-handed or bilateral expression. In contrast, left-handed expression of Pitx2 was switched to the right side by right activin injection. This is the first report of a method that achieves complete inversion of the visceral L-R axis by treatment of embryos at the neurula stage. Activin not only acts on the neurulae to cancel the original L-R specification up to the late neurula stage, but also rebuilds a new L-R axis whose left side coincides with the injection side. It is suggested that the left and right halves of neurulae have equal potential for L-R differentiation.

The Wada test: prediction of focus lateralization by asymmetric and symmetric recall

Purpose: The intracarotid amytal test is commonly used as a predictor of memory dysfunctioning after anterior temporal lobe resection (ATL) for intractable epilepsy. Asymmetry in memory scores can provide focus lateralizing information. In this study the predictive value of a set of Wada test parameters was analyzed, including patients with symmetrical memory scores. Methods: The Wada test was carried out in 226 patients undergoing ATL (94 L, 132 R). Data were collected on item recognition (five items), story recall, amytal dose, presentation time, EEG and arterial filling of amytal. A logistic regression analysis was performed on these data in order to find a set of variables which could best predict the side of seizure onset. Results: The analysis yielded four variables, i.e. both memory scores, story recall after right-sided injection and presentation time of stimuli after left-sided injection which could correctly predict seizure lateralization in 85% of the cases. Misclassification was lower for right foci than for left foci. Seizure outcome was four times more favourable in the correctly classified patients. Conclusions: The results suggest that prediction of focus lateralization in temporal lobe epilepsy can be fairly exact even if left/right memory scores are equal. Performing the Wada test with only five memory items keeps the time window of active amytal short enough and gives accurate information about contralateral temporal lobe functioning. The classification scheme can be useful in predicting a lowered chance of seizure freedom.

Suboptimal contrast-enhanced carotid MR angiography from the left brachiocephalic venous stasis.

The purpose of this study was to evaluate left brachiocephalic venous stasis and its relationship to suboptimal contrast-enhanced carotid magnetic resonance angiography (MRA). Two groups of patients (group 1, 475 patients; group 2, 159 patients) were examined by contrast-enhanced carotid MRA. Dynamic images of four serial phases were obtained by a three-dimensional fast low-angle shot (3D-FLASH) MRA sequence after bolus injection of 20 ml of gadolinium chelate. In group 1, 43 (9.1%) of 475 cases failed in optimal visualization of carotid arteries because of venous stasis. Left-side injection of contrast media was significantly related to venous stasis (42/43) (P < 0.0001). The patients with venous stasis had a higher mean age (54. 8 +/- 1.5 vs. 60.7 +/- 2.9 years) and higher incidence of hypertension (52.8% vs. 72.1%; P < 0.05). Venous stasis was found at the left brachiocephalic vein (42/43). Compression of the left brachiocephalic vein between the sternum and aorta was confirmed in four cases by venography, chest computed tomography, and magnetic resonance imaging. In group 2, right-side injection did not cause venous stasis at all. The results of this study suggest that use of the right arm for contrast media injection is preferable in the absence of contraindications. J. Magn. Reson. Imaging 1999;10:503-509.

Convection-enhanced selective excitotoxic ablation of the neurons of the globus pallidus internus for treatment of parkinsonism in nonhuman primates.

Selective treatment of central nervous system (CNS) structures holds therapeutic promise for many neurological disorders, including Parkinson's disease (PD). The ability to inhibit or augment specific neuronal populations within the CNS reliably by using present therapeutic techniques is limited. To overcome this problem, the authors modeled and developed a method in which convection was used to deliver compounds to deep brain nuclei in a reproducible, homogeneous, and targeted manner. To determine the feasibility and clinical efficacy of convective drug delivery for treatment of a neurological disorder, the investigators selectively ablated globus pallidus internus (GPi) neurons with quinolinic acid (QA), an excitotoxin, in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced model of primate parkinsonism. After the parameters of convective distribution to the GPi were confirmed by infusion of biotinylated albumin into the GPi of a primate (Macaca mulatta), seven adult monkeys of this species were rendered either fully parkinsonian by intravenous injections of MPTP (five animals) or hemiparkinsonian by a right-sided intracarotid injection of this agent (two monkeys). Using convection-enhanced delivery to the GPi, animals were infused with either QA (three fully parkinsonian, two hemiparkinsonian) or saline (two fully parkinsonian). The three fully parkinsonian animals that underwent GPi lesioning with QA had substantial improvement of PD symptoms, manifested by a marked increase in activity (34 +/- 2.5%; mean +/- standard deviation) and dramatic improvement of parkinsonian clinical scores. In contrast, the control animals did not improve (activity monitor change = -1.5 +/- 0.5%). The two hemiparkinsonian animals that underwent QA lesioning of the GPi had dramatic recovery of extremity use. Histological examination revealed selective neural ablation of GPi neurons (mean loss 87%) with sparing of surrounding gray and white matter structures. No animal developed worsening signs of PD or neurological deficits after infusion. Convection-enhanced delivery of QA permits selective, region-specific (GPi), and safe lesioning of neuronal subpopulations, resulting in dramatic improvement in parkinsonian symptomatology. The properties of convection-enhanced delivery indicate that this method could be used for chemical neurosurgery for medically refractory PD and that it may be ideal for cell-specific therapeutic ablation or trophic treatment of other targeted structures associated with CNS disorders.

Asymmetrical or heterogeneous enhancement of the internal jugular veins in contrast-enhanced CT of the head and neck.

With faster CT scanners, asymmetric/heterogeneous enhancement (ASHE) of the internal jugular veins (IJVs) is frequently encountered in the absence of pathology. We investigated the frequency, side, pattern and significance of ASHE in 200 patients with various head and neck lesions. Non-ionic contrast medium (300 mgI/ml) was infused into a forearm vein (right, n = 100); left, n = 100). Forty seconds after contrast medium injection, contiguous 5-mm-thick sections were obtained craniocaudally from the skull base to the aortic arch. CT machines with two different scanning cycle times (3 s, n = 100; 2 s, n = 100) were used. ASHE of the IJVs was observed in 51 patients (25.5%); the patient group receiving a right-sided injection with a 2-s scan cycle machine, showing a higher frequency (44%). ASHE was divided into four patterns: homogeneous low density, focal low density, heterogenous opacification and fluid-fluid level formation. ASHE was frequently observed in routine contrast-enhanced CT of the head and neck. Frequency of ASHE increased when the scanning cycle was shorter. We should be aware of this phenomenon to avoid its misinterpretation as venous thrombosis or other pathology.

Speech localization using repetitive transcranial magnetic stimulation

To evaluate whether repetitive transcranial magnetic stimulation (RTMS) may be used for speech localization, we compared the results from RTMS with the intracarotid amobarbital test (IAT) in 21 patients undergoing surgical treatment (amygdalohippocampectomy or anterior temporal lobe resection) for medically intractable partial epilepsy. None of the patients had aphasia. We stimulated the temporal and frontal cortex on each side at a frequency of 30 Hz for 1 second and increased the intensity until speech was inhibited. A list of words and forward and backward counting were used to test speech function. The IAT was performed on the hemisphere of proposed surgery by unilateral injection and simultaneous regional cerebral blood flow (rCBF) recordings. In one patient, there was doubt about hemisphere dominance and a second bilateral IAT was performed. Fifteen patients had left-sided speech dominance; one, left-sided dominance and a moderate right-sided speech inhibition; two, right-sided speech dominance; and one, bilateral speech representations (bilateral injection at the IAT) with both techniques. One patient showed bilateral with right-sided speech dominance by RTMS and showed right-sided speech inhibition with right-sided injection only at the IAT procedure. One patient differed from the rest, showing bilateral representations with right-sided speech dominance with RTMS and left-sided speech inhibition by IAT with left-sided injection only. The concordance was 95%. None of the patients had seizures provoked by the procedure. We conclude that speech localization with RTMS shows a high concordance with the results from the IAT and may be useful in addition to traditional techniques in speech localization.(ABSTRACT TRUNCATED AT 250 WORDS)

Successful and reproducible myocardial opacification during two-dimensional echocardiography from right heart injection of contrast.

Myocardial contrast echocardiography currently involves intro-arterial injection of contrast. For this technique to have a broader application, it is necessary that myocardial opacification be achieved from a venous injection of contrast. To achieve myocardial opacification after right-side injection of contrast, two groups of open-chest anesthetized dogs were studied. Group 1 included nine dogs in whom microbubbles of various sizes, concentrations, and volumes were injected into the left atrium to determine microbubble characteristics that influence myocardial opacification. Group 2 included eight dogs in whom the effect of the combination of microbubble characteristics and myocardial blood flow on myocardial opacification was evaluated after right atrial injection of contrast. Background-subtracted time-intensity plots were generated from the myocardium to measure peak videointensity. In the group 2 dogs, digital subtraction and color coding were used to further highlight the contrast effect. The number, concentration, and size of the microbubbles all independently affected (p less than 0.01) peak myocardial videointensity after left atrial injection of contrast on multivariate analysis. Highly concentrated microbubbles (4.4 to 5.1 billion/ml) given during dipyridamole-induced coronary hyperemia was most frequently (88%) associated with myocardial opacification after right atrial injection of contrast and was the best predictor of this result on multivariate analysis (chi 2= 9.01, p = 0.003). No changes were noted in left atrial, left ventricular, and pulmonary artery pressures despite injection of large numbers of microbubbles into the right atrium. Successful and reproducible myocardial opacification can be achieved during myocardial contrast echocardiography after right atrial injection of contrast. These findings could have far-reaching implications in the use of myocardial contrast echocardiography in acute and chronic ischemic syndromes in humans.

Two-dimensional contrast echocardiography. I. In vitro development and quantitative analysis of echo contrast agents

To facilitate the passage of echo contrast agents through the microcirculation and the echocardiographic study of myocardial perfusion, ultrasonic energy (sonication) was employed to produce contrast agents consisting of relatively uniform, stable and small (less than 10 mu diameter) gaseous microbubbles suspended in liquid solutions. The size and persistence of the microbubbles was verified by light microscopy and an in vitro system were employed for comparative assessment of peak echo amplitude and echo persistence characteristics of various contrast agents. The study indicated that although a variety of hand-agitated and sonicated contrast agents provided satisfactory echo intensities, sonication was clearly superior to the hand-agitation method, because sonication produced smaller, more uniform and more stable microbubbles that may be suitable for myocardial contrast echocardiography. It is concluded that of the contrast agents examined, sonicated solutions of sorbitol (70%) and dextrose (70%) appeared to have particular potential because of the small sizes of the microbubbles (6 +/- 2 and 8 +/- 3 mu, respectively) and their prolonged in vitro persistence. The use of sonication to produce standardized, small and stable microbubbles should facilitate physiologic passage of the contrast agent through the capillary beds and allow two-dimensional imaging of the left heart myocardium during right-sided, aortic root, coronary sinus or intracoronary contrast injections.