Comparison of Image Quality using Various Quantitative Evaluation Methods between Sequence and Spiral scan during Brain CT

손인철(In-Chul Son),이기백(Ki-Baek Lee) 대한CT영상기술학회 2020 대한CT영상기술학회지 Vol.22 No.2

두부 CT검사에는 고식적 방식과 나선형 방식이 있다.두부 CT검사 시 고식적 방식이 나선형 방식에 비해 화질이 더 우수하여 더 많이 사용되어왔다. 그러나 이러한 우수한 화질이라는 평가는 주로 정성적으로 평가한 것이 대부분이었으며 이는 객관성이 떨어진다는 제한점이 있다. 이에 본 연구는 다량한 정량적 평가를 하기 위하여 고식적 방식과 나선형 방식, 즉 2가지 검사방법을 동시에 시행한 적이 있는 환자 20명을 대상으로 CT Number, 영상 잡음, 대조도 대 잡음비 등 다양한 정량적 평가를 하였다. 또한 저대조도, 영역백질, 회백(질)의 구분을 위하여 ACR 팬텀의 모듈 2를 관전류초를 변화시키며 히스토그램 및 그래프를 이용해 두부 CT 영상 화질을 비교하였다. 후향적 환자 연구 시 CT Number, 영상 잡음, 대조도 대 잡음비 각각의 결과는 고식적 방식과 나선형 방식 순서로 31.73 ± 3.96 vs 31.92 ± 3.25, 3.53 ± 0.63 vs 4.1 ± 0.54, 275.82 ± 43.49 vs 239.76 ± 31.88이었다. 팬텀 연구의 경우 고식적 스캔 방식이 나선형 스캔 방식에 비해 보고자 하는 CT Number를 잘 표현했고 그래프화하였을 때 높은 첨도를 가지고 있었다. 결과적으로 고식적 방식이 나선형 방식에 비하여 우수한 화질을 가졌고, 히스토그램 기반으로 분석한 수치와 그래프를 이용한 방법은 영상 평가의 도구로 사용 시 유용할 수 있을 것이라 판단된다. There are two scan methods such as sequence and spiral scan in CT examination.I n Brain CT, the sequence scan mode has been utilized more than the spiral mode due to having better image quality.H owever, this evaluation of image quality was mainly subjective assessment and had some limitation.S o, we tried to analyze the image quality of brain CT between the sequence and spiral mode with 20 patients data and an ACR phantom by using various quantitative evaluation such as CT number, image noise, contrast to noise ratio (CNR), and histogram-based analysis.E ach result of CT number, image noise, CNR between two modes (Sequence vs Spiral) were as follows: 31.73 ± 3.96 vs 31.92 ± 3.25, 3.53 ± 0.63 vs 4.1 ± 0.54, 275.82 ± 43.49 vs 239.76 ± 31.88. Overall quantitative image quality of the sequence mode were better than the spiral mode in the study of patient images.A lso, histogram analysis by using the ACR phantom represented higher figures of targeted CT number in the sequence mode than the spiral mode. Additionally, all graphs of phantom images with the sequence scan had high profiles.A s a results, the sequence scan mode had better quantitative image quality and histogram based evaluation was proven by very useful method to distinguish the low contrast resolution between different two vague portions.

전산화단층촬영장치의 발달에 따른 검사 변화 추이

김민철(Min Cheol Kim),임청환(Cheong Hwan Lim) 대한CT영상기술학회 2011 대한CT영상기술학회지 Vol.13 No.1

목 적 1996년 이후부터 CT가 건강보험급여대상이 되면서 이용률과 보급률이 더욱 증가되고 있으며 검사범위의 확대, 검사시간의 단축, 반복검사의 용이성, 이용의 편리성, 결과의 신뢰성, 장치의 구조적인 요소 및 검사 시행 횟수의 증가 등으로 검사량이 증가되고 있는 실정이다. 대상 및 방법 CT 검사 건수의 증가요인으로 새로운 CT장비의 개발과 더불어 급격한 장비도입 증가 추세가 있으므로 이에 본 연구에서는 서울시 소재 K대학병원의 CT검사를 연도별/부위별 검사 건수 및 비율을 분석 하였으며, CT 장비의 도입시기에 따른 부위별 검사비율의 차이점을 파악하여 CT검사의 변화를 조사 분석하였다. 결 과 CT검사 변화 추이는 CT장비가 처음으로 도입되어 현재까지 운영되어 오고 있는 K 대학병원을 조사 연구한 결과 위와 같은 요인들로 인하여 1995년 Spiral CT가 도입되면서 Extremity검사가 가능해졌고, 2004년과 2006년 Multi slice CT의 도입으로 인하여 Heart검사가 가능해졌고, Head 검사는 3,4세대 장비를 사용하던 시기에 가장 많은 검사를 하였고, 다음은 Spiral 장비 시기, 그 다음이 MDCT 장비 시기 순으로 감소하였다(F = 69.52, p < .001). Chest 검사(F = 90.56, p < .001)와 Abdomen 검사(F = 191.43, p < .001), Spine 검사(F = 8.02, p < .01)는 Head 검사와는 달랐다. MDCT 장비 시기에 가장 많이 검사를 하고 있으며 그 다음은 Spiral 시기, 다음은 3,4 세대 장비 시기 순으로 감소하였다. 결국 장비의 발전에 따른 도입 시기에 따라 검사 변화의 추이가 변화됨을 알 수 있다. 결 론 이상의 본 연구 결과에서 고가의료영상 진단 장비인 CT의 세대별 발달장비 도입 시기에 따른 우리나라 CT의 현황과 검사건수의 변화를 파악하여, 의료기관의 장비도입에 따른 검사변화를 조사 분석하여 제시하여 고가의료장비 수급의 정책수립의 계기 및 기여하고자 한다. CT has become health insurance since 1996, its utilization factor and penetration rate have been increasing. Test rate increases by cause for expanding test range, shorter test hours, easy repeating test, convenient using, reliability results, its structured elements, and frequency of test. Developing new CT equipment and growing introduction CT, according to increasing frequency of CT test. Therefore, analyses CT test rate by year and tested parts, practiced in Seoul K University hospital. The study also grasps the difference of test rate by the year CT equipment introduced, and processes the change of CT test. CT changes get analyzed basis on K University Hospital, which introduced CT the first and still managing until these days. In 1995, Spiral CT was introduced, which in turns that being capable of Extremity test. In 2004 and 2006, Heart test could be possible, according to introduce Multi slice CT. There were much head tests practiced when third and forth generations equipments got used. The next, following the third and fourth generation using, is Spiral CT and MDCT used times (F = 69.52, p < .001). Chest test (F = 90.56, p < .001), Abdomen test (F = 191.43, p < .001), and Spine test (F = 8.02, p < .01) was different to Head test. In other words, much of tests are frequent with this order (max to min): MDCT, Spiral, and third and fourth generation equipments. Eventually, CT test changes following the time when CT introduced by development. The study understands the change of CT condition and test frequency of Korea by the time when the CT became introduced for each generation. And the study investigates the CT test changes by introducing equipments in hospitals. The outcomes of the study become presented and make a contribution to policy making for high priced medical equipments’ supply and demand.

위질환에서 나선식 CT를 이용한 횡단 CT 영상과 3D 입체영상의 소견 및 역할

이동호 대한영상의학회 1996 대한영상의학회지 Vol.35 No.5

Purpose : The purpose of this study is to assess the efficacy of axial CT imaging and 3D imaging by spiral CTin the detection and evaluation of gastric lesion. Materials and Methods : Seventy-seven patients withpathologically-proven gastric lesions underwent axial CT and 3D imaging by spiral CT. There were 49 cases ofadvanced gastric carcinoma(AGC), 21 of early gastric carcinoma (EGC), three of benign ulcers, three of leiomyomas, and one case of lymphoma. Spiral CT was performed with 3-mm collimation, 4.5 mm/sec table feed, and 1-1.5-mmreconstruction interval after the ingestion of gas. 3D imaging was obtained using the SSD technique, and onanalysis a grade was given(excellent, good, poor). Axial CT scan was performed with 5-mm collimation, 7mm/sectable feed, and 5-mm reconstruction interval after the ingestion of water. Results : Among 49 cases of AGC, excellent 3D images were obtained in seven patients (14.3%), good 3D images in 30(61.2%), and poor 3D images in12(24.5%). Among the 12 patients with poor images, the cancers were located at the pyloric antrum in eight cases, were AGC Borrmann type 4 in three cases, and EGC-mimicking lesion in one case. Using axial CT scan alone, Borrmann's classification based tumor morphology were accurately identified in 67.3% of cases, but using 3Dimaging, the corresponding figure was 85.7%. In 33 cases receiving surgery, good correlation between axial CT scanand pathology occurred in 72.7% of T class, and 69.7% of N class. Among 21 cases of EGC, excellent 3D images wereobtained in three patients (14.3%), good 3D images in 14 (66.7%), and poor 3D images in two (9.5%). The other twocases of EGC were not detected. By axial CT scan, no tumor was detected in four cases, and there were two doubtfulcases. 3D images of three benign ulcers were excellent in one case and good in two. 3D images of three leiomyomasand one lymphoma were excellent. Conclusion : Combined axial CT imaging and 3D imaging by spiral CT has thepotential to accurately diagnose gastric lesions other than AGC Borrmann type 4 or tumors located at the pyloricantrum.

대동맥궁 기형 환자에서 나선형 CT를 이용한 3차원 영상 진단의 유용성

김양민,김태훈,김미영 世宗醫學硏究所 2000 世宗醫學 Vol.17 No.2

삼차원 영상 구성에 의한 나선식 전산화단층혈관조영술의 유용성 : 양측성 윌름종양 수술에서의 경험

정병창,이승배,윤상진,오승준,이안기,김인원,최황 大韓泌尿器科學會 1999 Korean Journal of Urology Vol.40 No.3

삼중시기 나선형 CT를 이용한 간경변증 환자에서의 결절성 간세포암의 조영증강양상

김영화,윤종필,김형환,이상진,이혜경,김일영,장유진 순천향의학연구소 1996 Journal of Soonchunhyang Medical Science Vol.2 No.2

We evaluated the contrast enhancement pattern of nodular hepatocelluar carcinoma in liver cirrhosis patients by using three phase spiral CT. We anlayzed 34 nodular hepatocelluar carcinonmas in 11 patients with liver cirrhosis. Three phase spiral CT were obtained at 30(arterial phase), 60(portal phase), 180seconds(delayed phase) after initiation of contrast injection in the rate of 3ml/sec. Nodules are classified according to size, as group A(below 1cm, n=11), group B(1 - 3cm, n=15), group C(above 3cm, n=8). Enhancement pattern of the nodule was analyzed comparing to normal liver parenchyme in each phase., as total high, central high, peripheral high, iso, low, mixed density. We also analyzed the detection rate of the nodules. As a whole the nodules show high density in arterial phase(76%), high density in portal phase(47%) and low density in delayed phase(56%). In group A, the nodules show high(100%) in arterial phase, iso(54%) or high (46%) in portal phase, iso(82%) in delayed phase. In group B, the nodules show high(100%) in arterial phase, high(74%) in portal phase, mixed (60%) in delayed phase. In group C, the nodules show mixed density in all three phase. The most common enhancement pattern in each group was high(arterial phase) - iso(portal phase) - low (delayed phase) in group A(6/11, 54%), high - high - low in group B (5/15, 33%), mixed - mixed - mixed in group C(5/8, 63%). The detection rate of the nodule was highest in arterial phase, and the usefulness of arterial phase comparing to portal or delayed phase was higher in smaller size. In conclusion, hepatocelluar carcinomas show different enhancement pattern according to the size on three phase spiral CT, and this may be helpful in diagnosis of them.

뇌동맥류환자에서의 나선식 CT를 이용한 3D CT 혈관조영술의 이용 및 가치

박세혁,이규호,오세문 대한신경외과학회 1996 Journal of Korean neurosurgical society Vol.25 No.11

We evaluate the detection of cerebral aneurysms with 3-dimensional(3D) computed tomographic angiography(CTA) and compare the results with those of magnetic resonance angiography(MRA) and conventional cerebral angiography(CCA). Ten patients with 12 cerebral aneurysms were studied with spiral CT in conjunction with CCA and MRA. All aneurysms(3-20㎜ in diameter) were seen in CTA, MRA and CCA except 1 aneurysm(3㎜ in diameter) in MRA. CIA demonstrated neck, shape, direction of the aneurysm, and adjacent vascular and bony structures well. Of 12 aneurysms. 4 were seen equally with CCA and MRA. 4 were seen better with CCA owing to flow-related or motion artifact in MRA, and 4 were seen better with MRA. CTA was considered to be superior to CCA and MRA in demonstrating calcification and thrombosis in the aneurysm. 3D CTA with spiral CT is a rapid noninvasive method of visualizing the cerebral aneurysms and is comparable with MRA in demonstrating the aneurysms. We think 3D CTA can be a screening tool for use in the patients with suspected cerebral aneurysms and will be of a value in surgical planning for patients with complex cerebral aneurysms, in demonstrating the anatomy of the aneurysms and surrounding structures.

폐결절의 감별진단 : 이중시기 나선식 조영증강 CT의 유용성 Efficacy of Two-Phase Enhanced Spiral CT

박경주,강두경,황성철,이이형,서정호 아주대학교 의과학연구소 1998 아주의학 Vol.3 No.2

To evaluate the efficacy of two-phase enhanced spiral CT in differentiating between benign and malignant pulmonary nodules, 31 patients with pulmonary nodules with less than 5 cm in diameter underwent spiral CT at unenhanced, early, and late enhanced phases. Enhanced scans were carried out 30(early phase) and 70-180 sec (late phase) after intravenous injection of mixed solution of 100 mL 60% iodinated contrast media and 60 mL normal saline in a rate of 2.5 mL/sec. The pattern, measured degree of enhancement, and nodule-to-muscle enhancement ratio were compared between 17 benign (mean size: 2.8 cm, 15 tuberculomas included) and 14 malignant nodules (mean size: 3.6㎝). The degree of enhancement of nodules was higher in the late enhanced phase than in the early phase. The measured degree of enhancement was significantly greater in malignant nodules in the early (mean±SD: 13.0±10.9 HU) and late (19.0±9.7 HU) enhanced phases than in benign nodules (early: 3.4±4.2HU, late: 7.2±9.6 HU) (p<0.01 by Wilcoxon rank-sum test). Nodule-to-musde enhancement ratio was greater in malignant (2.1±1.2) than in benign nodules (0.5±0.7) in the late enhanced phase (p<0.01). The enhancing pattern of nodules was more efficiently evaluated with the late enhanced images. Most (70%) of the benign nodules showed no enhancement (23%) or thin rim enhancement in the peripheral region (47%). Malignant nodules were enhanced in homogeneous (57%), mosaic (29%), or peripheral pattern with thick enhancing rim (14%). Two-phase enhanced spiral CT is efficient in evaluation of the pattern and the degree of enhancement of pulmonary nodules and useful for noninvasive differential diagnosis.

나선식 CT를 이용한 혐색소형 신세포암과 투명세포형 신세포암의 감별

김홍철,조재호 영남대학교 의과대학 2012 Yeungnam University Journal of Medicine Vol.29 No.1

Background: The purpose of this study was to differentiate chromophobe renal cell carcinoma and clear cell renal cell carcinoma on helical CT. Methods: The CT images of 9 patients histopathologically proven to have chromophobe renal cell carcinoma and 20 patients with clear cell renal cell carcinoma were reviewed. The tumor sizes, margins, enhancement degrees and patterns, presence or absence of calcification, and tumor spread patterns(including perinephric changes, venous invasion, lymphadenopathy, and distant metastasis) were compared. Results: All the chromophobe renal cell carcinomas showed well-demarcated margins. Thechromophobe renal cell carcinomas showed milder enhancements than the clear cell renal cell carcinomas. The sensitivity and specificity for differentiating the chromophobe renal cell carcinoma from the clear cell renal cell carcinoma were 100 and 88%, respectively, when 101 Hounsfield units was used as the cut-off value in the corticomedullary phase, and 95 and 100% when a less-than-three-time enhancement change was used as a cut-off value in the corticomedullary phase(p<0.05). The chromophobe renal cell carcinomas(67%) tended to show a homogeneous enhancement whereas the clear cell renal cell carcinomas(85%) usually showed a heteroge- neous enhancement(p<0.05). Statistical analysis revealed that the frequencies of the tumor spread pattern and calcification in the two subtypes didnot differ significantly(p>0.05). Conclusion: The CT findings of the chromophobe renal cell carcinomascompared to those of the clear cell renal cell carcinomas showed that there were mild enhancements in the corticomedullary phase, homoge- neous enhancements, and well-demarcated margins.

Comparison of Target Localization Error between Conventional and Spiral CT in Stereotactic Radiosurgery

Kim, Jong-Sik,Ju, Sang-Kyu,Park, Young-Hwan 대한방사선치료학회 2000 大韓放射線治療技術學會誌 Vol.12 No.1

The accuracy of the target localization was evaluated by conventional and spiral CT in stereotactic radiosurgerv. Conventional and spiral CT images were obtained with geometrical phantom, which was designed to produce exact three-dimensional coordinates of several objects within 0.1mm error range. Geometrical phantom was attached by BRW headframe, intermediate head ring, and CT localizer. Twentv-seven slices of conventional CT image were scanned at 3 mm slice thickness. Spiral CT images were scanned at 3 mm slice thickness from the pitch value 1 to 3, and twenty-seven slices of image were obtained per each the pitch value. These CT images were transferred to a treatment planning system(X-knife, Radionics) by ethernet, Three-dimensional coordinates of these images measured from the treatment planning system were compared to known values of geometrical phantom. The mean localization error of the target localization of conventional CT was 1.4mm. In case of spiral CT, the error of the target localization was within 1.6mm from the pitch value 1 to 1.3, but was more than 30mm above the pitch value 1.5. In conclusion, as the localization error of spiral CT was increased in high pitch value compared to conventional CT, the application of spiral CT will be with caution in stereotactic radiosurgery.