Purpose Bismuth-impregnated latex shields are known to effectively reduce the radiation dose on the lens when performing head computed tomography (CT) scanning. The degree of shielding effect differs depending on how the shield is used. Following a phantom study performed in our institution, the present study prospectively examined the degree of deterioration of image quality in clinical images to determine whether bismuth shielding negatively affects the imaging diagnosis. Material and Method We included a total of 50 patients who underwent head CT scanning with bismuth shielding in our institution and had also undergone previous head CT scanning with the same scan setting. In the patients with shields and without shields, we measured CT values and noise at 22 individual points, and then two radiologists evaluated visual quality. A paired two-sample t-test was used to evaluate significant differences between these two groups. Result We excluded 13 of the 50 patients, because of severe degradation of image quality. CT value in the non-shielded patients were significantly different from those the shielded patients, except at three points; however, the difference was <2 HU except for the eyeballs. Image noise was also significantly different at five points, but the difference was <1 HU. Visual evaluation found a significant decrease in the image quality of the eyeball in the shielded patients, but no other effects were observed. Discussion and conclusion This study showed no significant decrease in the image quality of the head CT, except for the eyeballs. The results indicated that bismuth shielding can be considered an effective technique for reducing lens exposure. With the advancement in the new CT equipment in recent years, dose reduction is being without using shields. If this equipment becomes widespread, bismuth shielding would become unnecessary. However, as this will definitely take some time,, Bismuth shielding remains in significant use.
Background: Atrial fibrillation is a frequently observed arrhythmia that can cause cardiogenic cerebral embolism. However, the rate of detection of atrial fibrillation through 12-lead electrocardiography (ECG) or 24-h Holter ECG monitoring is low. Herein, we reported two cases in which we could detect paroxysmal atrial fibrillation using a patch-type long-term ECG recorder that can record continuously for≤14 days. Case 1: An 83-year-old man with a current history of hypertension, and atrial septal defect had become aware of palpitations. Although the 24-h Holter ECG did not detect arrhythmic events, long-term Holter ECG monitoring successfully recorded the evidence of symptomatic paroxysmal atrial fibrillation. Case 2: A 58-year-old man underwent a regular health checkup at his workplace, and atrial fibrillation was detected. Although the 24-h Holter ECG did not capture any arrhythmic events, long-term Holter ECG monitoring successfully provided diagnostic evidence of asymptomatic paroxysmal atrial fibrillation. Conclusion: Long-term Holter ECG monitoring may improve the clinical management of patients suspected of having cardiac arrhythmia diseases.
An 82-year-old man with a history of myocardial infarction and diabetes mellitus experienced dizziness for which he underwent head magnetic resonance imaging (MRI) that revealed incidental pituitary macroadenoma. Except for the occurrence of central hypothyroidism, the basal levels of pituitary hormones remained normal (TSH: 2.759 μIU/mL, FT4: 0.73 ng/dL, and FT3: 1.92 pg/dL). However, he was referred to our department for the evaluation and treatment of hyponatremia (Na: 123 mEq/mL) for which endocrine stimulation tests were performed. The patient received intravenous bolus injections of 250 μg of thyrotropin-releasing hormone, 100 mg of corticotropin-releasing hormone, and 100 μg of growth hormone-releasing peptide-2 separately on different days. Consequently, panhypopituitarism was detected, and hormone replacement therapy was initiated. Seven days after the last stimulation test, he developed a sudden headache without neuro-ophthalmic signs and impaired consciousness. Neither emergency computed tomography nor MRI performed 1 and 3 h, respectively, after the active episode disclosed any remarkable changes within the pituitary mass. MRI only was performed 24 h after symptom onset in which the T1-weighted image showed a high signal in the pituitary tumor, suggesting pituitary apoplexy (PA). The clinical course indicated the presence of PA, which commonly occurs within 2 days after stimulation tests and rarely thereafter. The symptoms in this patient appeared 7 days after the last stimulation test. Thus, although the involvement of other factors cannot be ruled out, PA might develop as long as 7 days after undergoing endocrine stimulation tests.