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BACKGROUND: In acute ischemic stroke (AIS), collateral status (CS) is an important predictor of favorable outcomes in patients with AIS. Among quantitative cerebral perfusion parameters, relative cerebral blood flow (rCBF) is considered an accurate perfusion-based indicator of CS. This study investigated the relationship between admission laboratory values, baseline characteristics, and CS as assessed by rCBF in patients with AIS-large vessel occlusion. METHODS AND RESULTS: In this retrospective multicenter study, consecutive patients presenting with AIS secondary to anterior circulation large vessel occlusion who underwent pretreatment computed tomography perfusion were included. The computed tomography perfusion data processed by RAPID (IschemaView, Menlo Park, CA) generated the rCBF. Binary logistic regression models assessed the relationship between patients' baseline characteristics, admission laboratory values, and poor CS. The primary outcome measure was the presence of poor CS, which was defined as rCBF <38% at a lesion size ≥27 mL. Between January 2017 and September 2022, there were 221 consecutive patients with AIS-large vessel occlusion included in our study (mean age 67.0±15.8 years, 119 men [53.8%]). Logistic regression showed that male sex (odds ratio [OR], 2.98 [1.59-5.59]; P=0.001), chronic kidney disease (OR, 5.18 [2.44-11.0]; P<0.001), admission National Institutes of Health Stroke Scale score ≥12 (OR, 5.17 [2.36-11.36]; P<0.001), and systolic blood pressure <140 (OR, 2.00 [1.07-3.76]; P=0.030) were associated with poor CS. CONCLUSIONS: Higher stroke severity on admission with National Institutes of Health Stroke Scale score ≥12, systolic blood pressure <140, chronic kidney disease, and male sex are statistically significantly associated with poor CS in patients with AIS due to anterior circulation large vessel occlusion as defined by rCBF <38%.
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Circulación Cerebrovascular , Circulación Colateral , Accidente Cerebrovascular Isquémico , Humanos , Masculino , Femenino , Anciano , Circulación Cerebrovascular/fisiología , Estudios Retrospectivos , Persona de Mediana Edad , Accidente Cerebrovascular Isquémico/fisiopatología , Accidente Cerebrovascular Isquémico/diagnóstico por imagen , Anciano de 80 o más Años , Imagen de Perfusión/métodos , Angiografía por Tomografía Computarizada , Angiografía Cerebral/métodosRESUMEN
BACKGROUND: Collateral status (CS) plays a crucial role in infarct growth rate, risk of postthrombectomy hemorrhage, and overall clinical outcomes in patients with acute ischemic stroke (AIS) secondary to anterior circulation large-vessel occlusions (LVOs). Hypoperfusion intensity ratio has been previously validated as an indirect noninvasive pretreatment imaging biomarker of CS. In addition to imaging, derangements in admission laboratory findings can also influence outcomes in patients with AIS-LVO. Therefore, our study aims to assess the relationship between admission laboratory findings, baseline characteristics, and CS, as assessed by hypoperfusion intensity ratio in patients with AIS-LVO. METHODS AND RESULTS: In this retrospective study, consecutive patients presenting with AIS secondary to anterior circulation LVO who underwent pretreatment computed tomography perfusion were included. The computed tomography perfusion data processed by RAPID (Ischema View, Menlo Park, CA) generated the hypoperfusion intensity ratio. Binary logistic regression models were used to assess the relationship between patients' baseline characteristics, admission laboratory findings, and poor CS. A total of 221 consecutive patients with AIS-LVO between January 2017 and September 2022 were included in our study (mean±SD age, 67.0±15.8 years; 119 men [53.8%]). Multivariable logistic regression showed that patients with AIS caused by cardioembolic and cryptogenic causes (adjusted odds ratio [OR], 2.67; 95% CI, 1.20-5.97; P=0.016), those who presented with admission National Institutes of Health Stroke Scale score ≥12 (adjusted OR, 3.12; 95% CI, 1.61-6.04; P=0.001), and male patients (adjusted OR, 2.06; 95% CI, 1.13-3.77; P=0.018) were associated with poor CS. CONCLUSIONS: Stroke caused by cardioembolic or cryptogenic causes, admission National Institutes of Health Stroke Scale score of ≥12, and male sex were associated with poor CS, as defined by hypoperfusion intensity ratio in the patients with AIS-LVO.
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Circulación Cerebrovascular , Circulación Colateral , Accidente Cerebrovascular Isquémico , Humanos , Masculino , Femenino , Anciano , Estudios Retrospectivos , Persona de Mediana Edad , Circulación Cerebrovascular/fisiología , Accidente Cerebrovascular Isquémico/fisiopatología , Accidente Cerebrovascular Isquémico/etiología , Accidente Cerebrovascular Isquémico/diagnóstico por imagen , Anciano de 80 o más Años , Imagen de Perfusión/métodos , Angiografía por Tomografía ComputarizadaRESUMEN
BACKGROUND: While the diagnosis of frontotemporal dementia (FTD) is based mostly on clinical features, [18F]-FDG PET has been investigated as a potential imaging golden standard in ambiguous cases, with arterial spin labeling (ASL) MRI gaining recent interest. PURPOSE: The purpose of this study is to conduct a systematic review and meta-analysis on the diagnostic performance of ASL MRI in FTD patients and compare it to that of [18F]-FDG PET. DATA SOURCES: A systematic search of PubMed, Scopus and EMBASE was conducted until March 13, 2024. STUDY SELECTION: Inclusion criteria were: original articles, patients with FTD and/or its variants, use of ASL MR perfusion imaging with or without [18F]-FDG PET, presence of sufficient diagnostic performance data. Exclusion criteria were: meeting abstracts, comments, summaries, protocols, letters and guidelines, longitudinal studies, overlapping cohorts. DATA ANALYSIS: The quality of eligible studies was assessed using the Quality Assessment of Diagnostic Accuracy Studies-2. Pooled sensitivity, specificity, and diagnostic odds ratio (DOR) for [18F]-FDG PET and ASL MRI were calculated, and a summary receiver operating characteristic curve was plotted. DATA SYNTHESIS: Seven eligible studies were identified, which included a total of 102 FTD patients. Aside from some of the studies showing at worst an unclear risk of bias in patient selection, index test, flow and timing, all studies showed low risk of bias and applicability concerns in all categories. Data from 4 studies was included in our meta-analysis for ASL MRI and 3 studies for [18F]-FDG PET. Pooled sensitivity, specificity and DOR were 0.70 (95% CI: 0.59-0.79), 0.81 (95% CI: 0.71-0.88) and 8.00 (95% CI: 3.74-17.13) for ASL MRI, and 0.88 (95% CI: 0.71-0.96), 0.89 (95% CI: 0.43-0.99) and 47.18 (95% CI: 10.77-206.75) for [18F]-FDG PET. LIMITATIONS: The number of studies was relatively small, with a small sample size. The studies used different scanning protocols as well as a mix of diagnostic metrics, all of which might have introduced heterogeneity in the data. CONCLUSIONS: While ASL MRI performed worse than [18F]-FDG PET in the diagnosis of FTD, it exhibited a decent diagnostic performance to justify its further investigation as a quicker and more convenient alternative. ABBREVIATIONS: 3DPCASL, 3D pseudocontinuous ASL; AD, Alzheimer's disease; ASL, arterial spin labeling; AUC, area under the curve; CI, confidence interval; DOR, diagnostic odds ratio; FN, false negative; FP, false positive; FTD, frontotemporal dementia; LE, limbic encephalitis; NLR, negative likelihood ratio; PASL, pulsed ASL; PLD, post-label delay; PLR, positive likelihood ratio; PRISMA, PSP, progressive supranuclear palsy; Preferred Reporting Items for Systematic Reviews and Meta-Analysis; SROC, summary receiver operative characteristic; TN, true negative; TP, true positive; QUADAS-2, Quality Assessment of Diagnostic Accuracy Studies-2.
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PURPOSE: Radiology faculty across various specialties have been reported to receive an average of 20.7 invitations to submit manuscripts to bogus journals and 4.1 invitations to speak at unsuitable events over a two-week span. Radiology trainees also receive a fair number of unsolicited invitations from unknown senders to submit manuscripts and speak at meetings. Trainees can be more vulnerable to predatory invitations due to potential naivety. We aimed to determine the prevalence of these spam invitations received by radiology trainees. MATERIAL AND METHODS: The designed survey for evaluating the experience of radiology trainees regarding phishing scams of predatory publications and conferences was sent to radiology residency and neuroradiology fellowship program leadership to redistribute amongst their trainees, and was advertised on social media platforms. The survey was first sent out on September 28, 2023, and was closed two weeks later October 12, 2023. Spearman's correlation, univariable and multivariable linear regression analyses were performed. RESULTS: Our study included 151 respondents who completed the survey. Of the survey respondents, 53 % reported receiving unsolicited emails from predatory publications (mean = 6.76 ± 7.29), and 32 % reported receiving emails from fraudulent conferences (mean = 5.61 ± 5.77). Significant positive correlation was observed between number of unsolicited email invitations with number of PubMed indexed publications, number as corresponding author, number in open access journals and number of abstract presentations. CONCLUSIONS: Trainees in radiology receive many unsolicited invitations to publish papers as well as to present at meetings that are not accredited. This could lead to wasted time and financial resources for unsuspecting trainees.
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Congresos como Asunto , Internado y Residencia , Radiología , Radiología/educación , Humanos , Encuestas y Cuestionarios , Edición/estadística & datos numéricos , Correo Electrónico , Fraude , Femenino , Masculino , Publicaciones Periódicas como AsuntoRESUMEN
RATIONALE AND OBJECTIVES: The number of international medical graduates (IMGs) entering radiology residencies and neuroradiology fellowships averaged 9.7% and 20.9% from 2021 to 2023, respectively. We aimed to determine whether IMG graduates are populating leadership roles at a proportionate rate in diagnostic radiology (DR) and neuroradiology. MATERIALS AND METHODS: We surveyed 191 DR program directors, 94 neuroradiology program directors (PDs), 192 chairs of radiology, and 91 directors of neuroradiology inquiring about their original citizenship and medical school (American Medical Graduates [AMG] vs IMG). We reviewed institutional websites to obtain missing data and recorded H indices for each person using Scopus. RESULTS: We confirmed the original citizenship and medical school location in 61-75% and 93-98% of each leadership group. We found that 16.2% of DR program directors, 43.7% of neuroradiology PDs, 28.5% of Chairs, and 40.6% of neuroradiology directors were not originally US citizens. The IMG rate was 18/188 (9.6%), 20/90 (22.2%), 26/186 (14.0%), and 19/85 (22.4%) for the same groups respectively. The most common country of origin and medical school cited was India for all leadership groups. IMGs had a median H index of 14 while AMG 10, significantly different (p = 0.021) CONCLUSION: Compared to the rate of diagnostic and neuroradiology trainees entering from 2021 to 2023, IMGs are proportionately represented at the leadership positions studied. The H index of the IMGs was higher than AMG. We conclude that IMGs have made substantial and proportionate inroads in radiology and neuroradiology leadership.
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BACKGROUND: Cervical spine computed tomography (CSCT) scans are frequently performed in older emergency department (ED) trauma patients based on the 65-year-old high-risk criterion of the Canadian Cervical Spine Rule (CCR). We sought to determine the positivity rate of CSCT scans in symptomatic and asymptomatic patients to assess the current applicability of age in the CCR. METHODS: We reviewed CSCT ED reports from two institutional hospitals from 2018 to 2023. The primary variable was age; however, we also recorded fracture types and sites and type of treatments. Patients were separated into symptomatic and asymptomatic cohorts. We used a Fisher's exact test to compare variables between the asymptomatic and symptomatic groups and chi-square tests for comparison between age groups. RESULTS: Of 9455 CSCTs performed in patients ≥ 65 years, 192 (2.0%) fractures were identified (113 females); 28 (0.30%) were in asymptomatic patients. The rates of fractures (1.6%) and asymptomatic fractures (0.18%) were lowest in the 65- to 70-year age group. There were no distinguishing features as to the level or part of the vertebra fractured or surgical treatment rate between asymptomatic and symptomatic patients. CONCLUSIONS: Cervical spine fractures in posttrauma patients ≥ 65 years are uncommon, with the lowest incidence in those 65 to 70 years old. Excluding asymptomatic individuals aged 65-70 from routine CSCT presents a minimal risk of missed fractures (0.18%). This prompts consideration for refining age-based screening and integrating shared decision making into the clinical protocol for this demographic, reflecting the low incidence of fractures and the changing health profile of the aging population.
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RATIONALE AND OBJECTIVES: Literature shows that discrimination has been pervasive in the field of medicine. The aim of this study was to collect experiences related to discrimination among US radiology residents, including type and source, as well as the residents' perception on lectures about discrimination and harassment. We also explored the barriers to reporting, and suggested strategies to overcome them. MATERIAL AND METHODS: Following Institutional Review Board (IRB) approval, an online survey was sent to program directors and coordinators across the US, who were asked to forward the link to their radiology residents. A reminder email was sent over a period of 4 months. The participants were reassured the survey was confidential and anonymous. RESULTS: Among the respondents, the most reported types of discrimination were based in gender, race and nationality, the majority of which not being reported. The most common perpetrators were attending radiologists, co-residents, technologists, and patients. The main barriers for reporting were fear of retaliation, confidentiality concerns, and skepticism about a positive outcome. CONCLUSION: Our study examines some experiences of discrimination shared by residents during their training, with gender and race being the most common causes. This sheds light into a hidden and unspoken issue and highlights the need for more active discussions in radiology on microaggressions and implicit bias. Our data can guide future studies as well as residency programs to build effective strategies to address discrimination, aiming for sustainable changes.
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Internado y Residencia , Radiología , Humanos , Masculino , Femenino , Radiología/educación , Encuestas y Cuestionarios , Estados Unidos , Adulto , Actitud del Personal de SaludAsunto(s)
Traumatismos Vertebrales , Heridas no Penetrantes , Humanos , Rayos X , Radiografía , Imagen por Resonancia Magnética , Traumatismos Vertebrales/diagnóstico por imagen , Tomografía Computarizada por Rayos X , Vértebras Cervicales/diagnóstico por imagen , Vértebras Cervicales/lesiones , Heridas no Penetrantes/diagnóstico , Estudios RetrospectivosRESUMEN
OBJECTIVE: For patients presenting with acute ischemic stroke (AIS) caused by large vessel occlusions (LVO), mechanical thrombectomy (MT) is the treatment standard of care in eligible patients. Modified Thrombolysis in Cerebral Infarction (mTICI) grades of 2b, 2c, and 3 are all considered successful reperfusion; however, recent studies have shown achieving mTICI 2c/3 leads to better outcomes than mTICI 2b. This study aims to investigate whether any baseline preprocedural or periprocedural parameters are predictive of achieving mTICI 2c/3 in successfully recanalized LVO patients. METHODS: We conducted a retrospective multicenter cohort study of consecutive patients presenting with AIS caused by a LVO from 1 January 2017 to 1 January 2023. Baseline and procedural data were collected through chart review. Univariate and multivariate analysis were applied to determine significant predictors of mTICI 2c/3. RESULTS: A total of 216 patients were included in the study, with 159 (73.6%) achieving mTICI 2c/3 recanalization and 57 (26.4%) achieving mTICI 2b recanalization. We found that a higher groin puncture to first pass time (OR = 0.976, 95%CI: 0.960-0.992, p = 0.004), a higher first pass to recanalization time (OR = 0.985, 95%CI: 0.972-0.998, p = 0.029), a higher admission NIHSS (OR = 0.949, 95%CI: 0.904-0.995, p = 0.031), and a lower age (OR = 1.032, 95%CI: 1.01-1.055, p = 0.005) were associated with a decreased probability of achieving mTICI 2c/3. INTERPRETATION: A lower groin puncture to first pass time, a lower first pass to recanalization time, a lower admission NIHSS, and a higher age were independent predictors of mTICI 2c/3 recanalization.
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Accidente Cerebrovascular Isquémico , Accidente Cerebrovascular , Humanos , Accidente Cerebrovascular/cirugía , Estudios de Cohortes , Accidente Cerebrovascular Isquémico/cirugía , Trombectomía , Estudios Retrospectivos , Resultado del Tratamiento , Infarto CerebralAsunto(s)
Arteriopatías Oclusivas , Isquemia Encefálica , Procedimientos Endovasculares , Accidente Cerebrovascular Isquémico , Accidente Cerebrovascular , Humanos , Accidente Cerebrovascular/terapia , Accidente Cerebrovascular/etiología , Isquemia Encefálica/terapia , Accidente Cerebrovascular Isquémico/etiología , Arteriopatías Oclusivas/etiología , Procedimientos Endovasculares/efectos adversosRESUMEN
OBJECTIVE: Unsolicited invitations to speak at medical meetings have proliferated as a type of spam email and phishing strategy to scam unsuspecting victims. We sought to determine the prevalence of such invitations to questionable meetings and determine the factors associated with receiving such solicitations. MATERIALS AND METHODS: Data was collected for the number of speakers' invitations received over a 2-week period (April -May 2023) by radiologists of different subspecialties, academic ranks, and histories of publications and speaking engagements in the past 2-5 years. We analyzed the number of invitations received based on the variables. RESULTS: Thirty-three of 45 (73.3%) faculty members received 188 inappropriate invitation emails in the 2-week observation period. The mean number of invitation emails was 4.13 for each faculty (SD: 5.03, range 0-20). There was no correlation between the number of invitations and radiologists' subspecialty, academic rank (3.8 ± 5, 3.0 ± 4, and 5.5 ± 5.7 invitations for full, associate, and assistant professors respectively) and previous legitimate speaker invites. Only 6 (3.2%) out of 188 invitations to speak sent to radiologists were for radiology-related meetings. Having more than 10 publications since 2022 was associated with a 5.0 (1.2, 19.4) times higher odds of receiving more than 4 solicitations. CONCLUSIONS: A total of 73.3% of the faculty surveyed received unsolicited invitations to meetings in the 2-week study period and over 96% of the invitations were unrelated to their field of practice. Our results show that publications since 2022 was the most significant factor associated with receiving more solicitations. CLINICAL RELEVANCE/APPLICATION: Invitations to questionable meetings targeting radiologists are frequent and often are unrelated to their specialties. The risk factors for receiving the invitations are unclear. Understanding these risk factors may enable educators especially junior investigators, to be better prepared to appropriately address such solicitations.
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Isquemia Encefálica , Procedimientos Endovasculares , Accidente Cerebrovascular Isquémico , Accidente Cerebrovascular , Humanos , Accidente Cerebrovascular Isquémico/cirugía , Trombectomía , Accidente Cerebrovascular/cirugía , Resultado del Tratamiento , Isquemia Encefálica/complicaciones , Isquemia Encefálica/cirugíaAsunto(s)
Isquemia Encefálica , Procedimientos Endovasculares , Accidente Cerebrovascular , Humanos , Isquemia Encefálica/tratamiento farmacológico , Procedimientos Endovasculares/efectos adversos , Sistema de Registros , Accidente Cerebrovascular/tratamiento farmacológico , Trombectomía , Terapia Trombolítica/efectos adversos , Activador de Tejido Plasminógeno/uso terapéutico , Resultado del TratamientoRESUMEN
It has been well documented that chronic stress can induce atherosclerotic changes, however, the underlying mechanisms is yet to be established. In this regard, this study aimed to elucidate the relation between hypothalamic-pituitary adrenal-axis (HPA-axis), toll-like receptors (TLRs), as well as M1/M2 macrophage ratio and pre-atherosclerotic changes in social isolation stress (SIS) in mice. We used small interfering RNA against the glucocorticoid receptor (GR) to evaluate the relation between HPA-axis and TLRs. C57BL/6J mice were subjected to SIS and RT-PCR, ELISA, flow cytometry, and immunohistochemistry were used to assess the relations between pre-atherosclerotic changes and TLRs, macrophage polarization, pro-inflammatory cytokines, and cell adhesion molecules in aortic tissue. We used TAK-242 (0.3 mg/kg, intraperitoneally), a selective antagonist of TLR4, as a possible prophylactic treatment for atherosclerotic changes induced by SIS. We observed that isolated animals had higher serum concentration of corticosterone and higher body weight in comparison to normal animals. In isolated animals, results of in vitro study showed that knocking-down of the GR in bone marrow-derived monocytes significantly decreased the expression of TLR4. In vivo study suggested higher expression of TLR4 on circulating monocytes and higher M1/M2 ratio in aortic samples. Pathological study showed a mild pre-atherosclerotic change in isolated animals. Finally, we observed that treating animals with TAK-242 could significantly inhibit the pre-atherosclerotic changes. SIS can possibly increase the risk of atherosclerosis through inducing abnormal HPA-axis activity and subsequently lead to TLR4 up-regulation, vascular inflammation, high M1/M2 ratio in intima. Thus, TLR4 inhibitors might be a novel treatment to decrease the risk of atherosclerosis induced by chronic stress.
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Aterosclerosis/etiología , Estrés Psicológico/complicaciones , Sulfonamidas/farmacología , Receptor Toll-Like 4/antagonistas & inhibidores , Animales , Aterosclerosis/fisiopatología , Aterosclerosis/prevención & control , Células Cultivadas , Modelos Animales de Enfermedad , Técnicas de Silenciamiento del Gen , Humanos , Sistema Hipotálamo-Hipofisario/fisiopatología , Activación de Macrófagos , Masculino , Ratones , Sistema Hipófiso-Suprarrenal/fisiopatología , Cultivo Primario de Células , Receptores de Glucocorticoides/genética , Receptores de Glucocorticoides/metabolismo , Aislamiento Social/psicología , Estrés Psicológico/inmunología , Estrés Psicológico/metabolismo , Estrés Psicológico/psicología , Sulfonamidas/uso terapéutico , Receptor Toll-Like 4/metabolismo , Regulación hacia ArribaRESUMEN
Social isolation stress (SIS) as a chronic model of early-life stress could induce proconvulsant effects in mice. In the current study, we evaluated the role of opioid receptors (OPRs) agonists and antagonists in pro-conversant effects of SIS and the common pathway between delta-opioid receptors (DORs) and nitric oxide (NO) in stress-induced seizure. For reaching to this goal, we used pentylenetetrazol (PTZ) model of clonic-seizure to measure seizure threshold and administrated selective and non-selective OPRs agonists and antagonists in both social condition (SC) and isolated condition (IC) animals. In the next step, we administrated sub effective dose of naltrindole (NLT, 0.3 mg/kg) with sub-effective doses of nitric oxide synthesis (NOS) inhibitors including L-NAME (10 mg/kg), aminoguanidine (50 mg/kg) and 7-NI (15 mg/kg). Also, we co-administrated sub-effective dose of SNC80 (0.5 mg/kg) with sub-effective dose of l-arg (25 mg/kg) to assess the seizure threshold. In addition, we measured nitrite levels of hippocampus following administration of mentioned drugs in both SC and IC mice. Our findings showed that L-NAME and 7-NI (but not AG) increased anti-convulsant activity of NLT and l-arg increased proconvulsant effects of SNC80 in IC animals. Nitrite assay showed that co-administration of NLT plus sub-effective doses of L-NAME and 7-NI (but not AG) decreased and co-administration of SNC80 with sub-effective dose of l-arg increased nitrite levels of hippocampus in IC mice. This study suggests the role of n-NOS in anti-convulsant effects of NLT and pro-convulsant effects of SNC80 in stress-induced seizure.
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Anticonvulsivantes/farmacología , Hipocampo/efectos de los fármacos , Naltrexona/análogos & derivados , Antagonistas de Narcóticos/farmacología , Óxido Nítrico/metabolismo , Receptores Opioides delta/antagonistas & inhibidores , Convulsiones/prevención & control , Aislamiento Social , Estrés Psicológico/complicaciones , Animales , Modelos Animales de Enfermedad , Hipocampo/metabolismo , Hipocampo/fisiopatología , Masculino , Ratones , Naltrexona/farmacología , Óxido Nítrico Sintasa de Tipo I/metabolismo , Pentilenotetrazol , Receptores Opioides delta/metabolismo , Convulsiones/etiología , Convulsiones/metabolismo , Convulsiones/fisiopatología , Transducción de SeñalRESUMEN
CONTEXT: Previous studies have suggested subtle anatomical brain differences between patients with schizophrenia and healthy control subjects. However, the results are inconsistent and there is no study investigating the various subtypes of this mental disorder separately. AIM: This study was conducted to compare the rate of absence of adhesio interthalamica (AI), a midline brain structure, between 3 subtypes of schizophrenia (paranoid, undifferentiated, and residual) and healthy control group, using magnetic resonance imaging (MRI). MATERIALS AND METHODS: A total of 29 schizophrenia patients (21 men, 8 women) of three subtypes (paranoid, undifferentiated, and residual) were compared with 29 age- and gender-matched healthy controls. All subjects underwent 3-D brain MRI of full coronal series, 1.5-mm slices without interslice gaps. If the grey matter band connecting the thalami could not be identified on two or more coronal adjacent slices, the AI was considered as absent. The results were statistically analyzed. RESULTS: The incidence rate of AI absence in patients with heterogenous subtypes of schizophrenia was was similar to control group, even when patients and controls of each gender were compared separately (P>0.05). In residual subtype, patients showed a significant priority in AI absence in comparison with the control group (P=0.041), which was not seen in paranoid and undifferentiated subtypes (P>0.05). CONCLUSION: Residual subtype of schizophrenia is associated with higher rate of AI absence in this study. Subsequent studies are required to determine if the absence of AI is a cause of residual schizophrenia or an effect.