Biomedical subjects
Publications and source records attributed to Hakan Ay.
We present the case of a patient who attempted suicide by ingesting matchstick heads (55% potassium chlorate). The patient presented to the emergency room with loss of consciousness, and MR imaging revealed symmetric hyperintense signal within the deep gray matter and medial temporal lobes. The patient improved after undergoing conventional treatment and hyperbaric oxygen.
PURPOSE: To compare the diagnostic accuracy of computed tomography (CT) and magnetic resonance (MR) imaging in a consecutive series of patients at presentation to the emergency department with symptoms of acute stroke. MATERIALS AND METHODS: Clinical data and images obtained in 691 consecutive patients with suspected acute stroke were examined. Results of first and second head CT and brain diffusion-weighted (DW) and conventional MR imaging were compared with each other and with the final neurologic discharge diagnosis. RESULTS: Five hundred seventy-three patients underwent CT at presentation, with 42% sensitivity (95% CI: 37%, 46%) and 91% specificity (95% CI: 82%, 96%). A total of 173 patients underwent a second CT examination, with 77% sensitivity (95% CI: 70%, 84%) and 79% specificity (95% CI: 49%, 95%). Of 498 MR images, 411 were DW, with 94% sensitivity (95% CI: 1%, 96%) and 97% specificity (95% CI: 88%, 100%), and 87 were conventional, with 70% sensitivity (95% CI: 58%, 81%) and 94% specificity (95% CI: 70%, 100%). By using DW MR imaging in the early period (<6 hours after presentation to emergency department), a 97% sensitivity (95% CI: 92%, 100%) and a 100% specificity (95% CI: 69%, 100%) were achieved, compared with 58% (29%-84%) and 100% (16%-100%), respectively, with conventional MR imaging, and 40% (35%-45%) and 92% (84%-97%), respectively, with CT. Negative predictive value was higher with DW MR imaging (73%) than with conventional (42%) MR imaging or CT (24%). In studies conducted within 12 hours, DW MR imaging achieved substantially superior accuracy than did CT. After 12 hours, accuracy was equivalent. CONCLUSION: In the diagnosis of stroke in the early period (<12 hours after presentation), DW MR imaging is superior to conventional MR imaging and CT.
Progressive clinical deterioration over a period of weeks coupled with MRI evidence of infarction growth is quite uncommon. In this report, we describe a patient with an occluded left anterior cerebral artery (ACA) at the origin of the A2 segment. His symptoms attributable to a posteriorly located small infarction within the ACA territory slowly progressed during the following 8 weeks. A follow-up MRI revealed that the infarction had expanded to involve the whole region of the left ACA. Occasional patients like ours indicate that stroke is a dynamic disorder with an extremely variable clinical course and state of tissue injury.
OBJECTIVE: Diffusion-weighted imaging (DWI) conveys temporal as well as anatomic information about brain infarction, and is therefore well suited to identify ischemic injury that has occurred simultaneously, or closely linked in time, with a transient ischemic attack (TIA). We aimed to determine the proportion and clinical characteristics of patients with TIA who harbor infarction(s) on DWI. METHODS: Using T(2)-weighted imaging (T(2)-WI), fast fluid attenuated inversion recovery (FLAIR), and DWI, we studied 57 consecutive patients presenting with acute focal neurologic symptoms lasting less than 24 h. RESULTS: A hyperintense DWI lesion was identified in a vascular territory appropriate to the symptoms in 27 patients (47%). Lesions judged to be clinically appropriate on T(2)-WI and FLAIR overlapped with a DWI lesion in 41 and 48% of patients, respectively. Independent predictors of infarction on DWI were previous nonstereotypic TIAs, presentation with motor symptoms, and identified stroke mechanism. CONCLUSION: DWI establishes that recent infarction occurs in almost half of patients with the clinical syndrome of TIA and this subgroup is more likely to harbor an underlying cardiac or cerebrovascular abnormality.
BACKGROUND AND PURPOSE: Creatine kinase-MB (CK-MB) increases in some patients with stroke, with no clear evidence of an acute coronary syndrome. Its elevations have been suggested to represent a biological marker for stroke-related myocardial injury. Troponin T has superior sensitivity and specificity to CK-MB in revealing minor myocardial injury. Therefore, we studied troponin T levels after stroke to determine whether troponin T increases in parallel to CK-MB. METHODS: We made daily measurements of CK-MB, myoglobin, total creatine kinase (total CK), and troponin T levels up to day 5 in 32 patients with large hemispheric infarction and with no history of coronary heart disease. The daily enzyme levels were compared with those of a control group of 22 patients with neurological diseases other than stroke. RESULTS: Serum CK-MB, myoglobin, and total CK levels were elevated above the cutoff value in 11, 26, and 20 patients with stroke, respectively. These enzyme levels gradually increased within the first 3 days and declined afterward. Troponin T did not exceed the reference range in any patients. One patient had elevated myoglobin and 3 had elevated total CK in the control group. The difference between groups was significant for CK-MB, myoglobin, and total CK at various time points. CONCLUSIONS: Troponin T, a more specific biochemical marker of myocardial injury, does not increase after stroke. Normal troponin T along with elevated CK-MB signifies that CK-MB is not the biological marker for myocytolysis. CK-MB elevations in stroke patients are likely to be noncardiac in origin.
Primary angiitis of the CNS is histopathologically characterized by ischemic lesions and small petechial hemorrhages. Unlike CT or conventional MR imaging, gradient-echo MR imaging depicts these chronic petechial hemorrhages. We herein report the case of biopsy-proved primary angiitis of the CNS in a 42-year-old man; whom gradient-echo MR imaging revealed multiple petechial hemorrhages in the cortical-subcortical brain regions. The identification of petechial hemorrhages by gradient-echo MR imaging promises to be a valuable surrogate marker supporting the diagnosis of primary angiitis of the CNS.
PURPOSE: Tracheal stenosis or neoplastic changes, as well as, traumatic, congenital, or iatrogenic causes may require extensive tracheal resections. Complications like vascularization insufficiency and structural support problems occur nearly in all cases when end-to-end anastomosis of trachea is not feasible. Hyperbaric oxygen (HBO) treatment is a well-known method for the management of grafts and flaps that have vascularization problems. In this study, the effect of hyperbaric oxygen treatment on wound healing after tracheal reconstruction with auricular cartilage graft (ACG) has been evaluated. METHODS: Thirty-two rabbits were divided into 2 groups: study group (n = 16) and control group (n = 16). The anterior halves of the six tracheal rings were resected, and the defects were repaired with autogenic auricular grafts. Hyperbaric 100% pure oxygen was administered to the study group at 2.4 atmospheres of absolute pressure 2 times a day for 1 week. The control group did not receive any therapy except proper control of the wound. RESULTS: It was observed that in the study group, inflammation, fibrosis, and necrosis were less, whereas epithelialization and maturation were early and neovascularization and neochondrification were more than the control group only at specific weeks. But all tracheas in both groups showed excellent healing without graft rejection and excessive granulation tissue formation. Furthermore, there was no statistically difference between the 2 groups. CONCLUSIONS: Auricular cartilage grafts is a valuable management method of tracheal defects, and hyperbaric oxygen treatment is a good supplementary method in healing period of cartilage autografts.
Buerger's disease is a recurrent inflammatory, nonatherosclerotic vasoocclusive disease, which typically affects small and medium-sized arteries, veins, and nerves of the upper and lower extremities. Systemic manifestations involving cerebral, mesenteric, and coronary arteries are exceptional. Moreover, multisystem involvement of 2 or more organs is extremely rare. The authors present a case of Buerger's disease in a patient who subsequently developed cerebral and bowel infarcts as well as cavernomatous transformation of the portal vein. Therefore, Buerger's disease, although rare, does have a chronic aggressive nature in some patients.