Radiation Dose Reduction without Compromise to Image Quality by Alterations of Filtration and Focal Spot Size in Cerebral Angiography

OBJECTIVE: Different angiographic protocols may influence the radiation dose and image quality. In this study, we aimed to investigate the effects of filtration and focal spot size on radiation dose and image quality for diagnostic cerebral angiography using an in-vitro model and in-vivo patient groups. MATERIALS AND METHODS: Radiation dose and image quality were analyzed by varying the filtration and focal spot size on digital subtraction angiography exposure protocols (1, inherent filtration + large focus; 2, inherent + small; 3, copper + large; 4, copper + small). For the in-vitro analysis, a phantom was used for comparison of radiation dose. For the in-vivo analysis, bilateral paired injections, and patient cohort groups were compared for radiation dose and image quality. Image quality analysis was performed in terms of contrast, sharpness, noise, and overall quality. RESULTS: In the in-vitro analysis, the mean air kerma (AK) and dose area product (DAP)/frame were significantly lower with added copper filtration (protocols 3 and 4). In the in-vivo bilateral paired injections, AK and DAP/frame were significantly lower with filtration, without significant difference in image quality. The patient cohort groups with added filtration (protocols 3 and 4) showed significant reduction of total AK and DAP/patient without compromise to the image quality. Variations in focal spot size showed no significant differences in radiation dose and image quality. CONCLUSION: Addition of filtration for angiographic exposure studies can result in significant total radiation dose reduction without loss of image quality. Focal spot size does not influence radiation dose and image quality. The routine angiographic protocol should be judiciously investigated and implemented.

Clinical Analysis of Refractory Epistaxis / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Epistaxis is a frequently seen disease in the field of otorhinolaryngology. However, many patients have to revisit the hospital because of the failure of the initial treatment, in which cases, the inconvenience is greater due to more severe bleeding. We studied epistaxis patients who visited our service during the last 10 years to analyze the causes of visits and the possible countermeasures. SUBJECTS AND METHOD: We studied retrospectively the clinical cases of 616 emmergency patients and 65 patients admitted for the treatment of epistaxis during the last 10 years, from August 1995 to July 2004. The group I, 505 patients (74.2%), improved with only one treatment. The group II, 176 patients (25.8%), showed refractory epistaxis following the initial treatment. RESULTS: In the group I, Kisselbach's area (68.1%) was the most common site to be treated, followed by Woodruff's area (13.5%), anterior end of inferior turbinate (8.3%), and superior portion of septum (2.0%). In the group II, the most frequent area to be treated was Woodruff's area (46.0%), followed by Kisselbach's area (31.8%), superior portion of septum (4.6%), anterior end of inferior turbinate (4.0%). CONCLUSION: The most important factor in the failure of primary care was because the precise area of bleeding was not found at the time of initial treatment. Therefore, it is important that we must check the areas by endoscope carefully to decrease the failure of initial treatment of epistaxis.

A Case of Condyloma Acuminatum of Pharynx / 대한이비인후과학회지

Condyloma acuminatum is one of the four types of common human venereal diseases that have viral etiology. Also known as a "moist wart", condyloma acuminatum is most often seen on the mucosal surface of the anogenital area. However, occurrences on the mucosal surface of head and neck regions are quite rare. We have recently encountered a case of condyloma acuminatum on the mucosal surface of pharynx, verified by histologic examination. We report a case of condyloma acuminatum on the mucosal surface of pharynx with a review of related literatures.

The Change of Lung Volume after Uvulopalatopharyngoplasty in Obstructive Sleep Apnea Patients / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: The objective of this research was to study the change of lung volume after uvulopalatopharyngoplasty (UPPP) in obstructive sleep apnea (OSA) patients. MATERIALS AND METHOD: Eight OSA patients were participated in this study. These patients were treated with UPPP at Seoul adventist hospital. Vital capacity (VC), inspiratory capacity (IC), expiratory residual volume (ERV) and FEV1, FEV1/FVC, FEV25-75% were determined by standard spirometry at the preoperative, at 3 postoperative days and 1 postoperative month. RESULTS: Vital capacity (VC) was significantly larger at 3 post-operative days (3.58+/-0.87 L, mean+/-SD) than those at pre-operative (3.12+/-0.69 L, mean+/-SD) in the patient with OSA (p=0.047). FEV 1 (L) was larger at 3 post-operative days (2.91+/-0.76 L, mean+/-vSD) than those at pre-operative (2.68+/-0.85 L, mean+/-vSD), but was not significantly correlated statically (p=0.249). CONCLUSION: We found significant correlation between preopeative and postoperative VC, IC.

Redo Operations for Recurrent Dissection After Operation for Type A Aortic Dissection / 대한흉부외과학회지

BACKGROUND: Stanford type A aortic dissection after graft replacement of ascending aorta and/or aortic arch required careful follow-up due to progression of the enlarged false lumen or the recurrence of dissection. From June 1984 to June 2000, 124 patients underwent operations for type A aortic dissection. Among them, 6 patients underwent reoperation due to recurred aneurysm or dissection. We evaluated that the causes of reoperation, including Marfan syndrome, the approach and result of reoperation, and strategy to reduce the risk of reoperation. MATERIAL AND METHOD: The first operation was done on acute stage in 4 cases, and chronic stage in 2 cases. There were Marfan syndromes in 3 cases. The entry site was the ascending aorta for all cases except one who underwent Bentall operation(n=3) or ascending aorta graft replacement(n=2). In one case, Bentall operation and total arch replacement was performed due to chronic type A dissection with multiple fenestrations. Mean interval of reoperation was 67.6months(range 5 months to 14 year 4months) after the first operation. Reoperations were performed with recurrence of dissection(n=4), threatening aneurysmal evolution of persisting dissection(n=1), and false aneurysm with infection(n=1). The redo operation involved the hemiarch in 1 case, distal ascending to total arch and descending thoracic aorta in 4 cases, and only descending thoracic aorta in 1 case. RESULT: There were Marfan syndromes in 18 patients. The mean age in type A dissection was 56.7 years and that in the first operation of reoperation cases was 32.2 years. Especially in 3 patients with Marfan syndrome, the mean age was 29 years. All patients who underwent reoperation survived. Postoperative complications were bleeding and tracheostomy in 1, mediastinitis in 1 and transient delirium in 1 case. Postoperatively, all the patients were followed-up in regular interval. Five patients were evaluated with computerized tomography, 1- 79months(mean: 31.5months) after the reoperation. The false lumen had regressed in 1 cases, persisted without progression in 4 cases. CONCLUSION: The clinical results of reoperation after type A aortic dissection operation were satisfactory. In younger patients with Marfan syndrome, the risk of reoperation was high. Careful and regular follow-up for the persistent false lumen is necessary.

Long-Term Results of Atrial Fibrillation Surgery with Mitral Valvular Disease / 대한흉부외과학회지

BACKGROUND: With mitral valvular heart disease, chronic atrial fibrillation(AF) is not likely to return to sinus rhythm after the operation. We evaluate the long term results and factors in recurrence of AF after modified Maze operation with mitral valve surgery. MATERIAL AND METHOD: From 1990 to 1996, 35 patients with chronic AF underwent modified Maze operation with mitral valve procedure in patients with chronic AF. The mean duration of AF was 7.7 +/-4.5 years. The concomitant operations were 34 mitral valve replacement(with 4 tricuspid annuloplasty and 3 tricuspid valve replacement)and 1 mitral valve repair. We analyzed the long term results and factors in recurrence of AF. RESULT: At immediate postoperatively, 33 of the 35 patients(93.9%) were converted to sinus rhythm. There was one operative death. However, AF recurred in 12 out of 35 patients during hospitalization and AF in these 12 patients were treated with antiarrhythmic drugs and electrical defibrillation 2-3 months later. Two out of twelve patients were failed in conversion to sinus rhythm after cessation of medication with side effects. During follow-up(71.1 +/-17.5 months, range 3-9 years), AF recurred in 9 patients and overall conversion rate to sinus rhythm was 73.5%. Predictors of postoperative AF included: duration of preoperative AF(maintenance group: recurrence group=6.3 years VS. 10.3 years, p=0.008) and cardiothoracic ratio on preoperative chest X-ray(0.58 VS. 0.72, p=0.009). CONCLUSION: AF surgery with mitral valve procedure increase the chance of recovery into sinus rhythm, reduce the incidence of atrial arrhythmia, and reduce the left atrial size with decreasing wall stress simultaneously. In order to decrease the incidence of postoperative arrhythmia, proper modification of the surgery with medical therapy should be considered.