원저 접수번호 :08-102(2 차 pdf) 건국대학교의학전문대학원영상의학교실, 신경과학교실 a 최영칠신현준최진영 a T and MR Imaging nalysis of alcification Suspensions of Different Types and oncentrations Young-hil hoi, MD, Hyun-Joon Shin, MD, Jin-Yong hoi, MD a Department of Radiology and Neurology a, School of Medicine, Konkuk University, hungju, Korea ackground: High-density calcifications on T images can appear as high signals on T1-weighted MR images, but with differing extents and degrees. This study investigated T and MR images of calcifications of various types and concentrations. Methods: We analyzed T and MR images of two cases of bilateral basal ganglia calcifications and experimental suspensions of calcifications of different types and concentrations. Results: The density of T calcifications increased in proportion to their concentration regardless of their type. However, the MR signals differed with the types and concentrations of calcification. high signal was one of the most noticeable signs on T1-weighted MR images for calcium phosphate, and it increased for concentrations up to 0.2 g/ml before leveling off. The signal for all types of calcification decreased on T2-weighted and especially fluid-attenuated inversion recovery (FLIR) images. onclusions: High signals are characteristic of calcification on T1-weighted MR images, and are often stronger than those on T images. low signal appears consistently on FLIR MR images regardless of the calcification type. These findings might be helpful in evaluating calcifications apparent in MR images. J Korean Neurol ssoc 27(2):158-162, 2009 Key Words: rain, alcification, omputed tomography, Magnetic resonance 서론 뇌 T에서고밀도를보이는석회화중일부는뇌 MRI T1 강조영상에서고신호강도를보이는것으로알려져있으나, 1-4 그범위와정도는 T와 T1 강조 MRI 에서차이가있다. T2 강조 MRI 에서석회화는 T2 단축과저신호강도를보이는것으로되어있으나, 1,2,4 액체감쇄반전회복영상 (Fluid ttenuated Inversion Recovery: FLIR) 영상에서어떻게나타나는지에대해서나 MRI 에서석회화를정확히반영하는영상기법에대한연구는 Received November 5, 2008 Revised December 23, 2008 ccepted December 31, 2008 *Jin-Yong hoi, MD Department of Neurology, School of Medicine, Konkuk University 620-5 Gyohyeon 2-dong, hungju-si, hungbuk, 380-704, Korea Tel: +82-43-840-8231 Fax: +82-43-854-2625 E-mail: jychoinr@kku.ac.kr 찾지못했다. 이에저자들은석회화가종류와농도에따라 MRI 의여러영상에서어떻게나타나고, T에서는어떻게보이는지를비교측정하여석회화가있는병변에대한 MRI 의판독에도움을주고자하였다. 대상과방법 뇌 T에서양측바닥핵에고밀도의석회화가관찰되는환자 2명의 MRI T1강조영상, T2강조영상및 FLIR 영상을관찰하였다. 인산칼슘 (calcium phosphate, ahpo 4), 탄산칼슘 (calcium carbonate, ao 3) 과수산기인회석 (hydroxylapatite, 3a 3 (PO 4) 2a(OH) 2) 을초음파겔 ( 주성분은물과소량의 polyacrylic acid) 에섞어다양한농도의현탁액을만들었다. 초음 158
D D Figure 1. 30-year-old woman with hypoparathyroidism (case 1).. High densities are seen on both sides of the basal ganglia on T images without contrast enhancement.. High signals appear on a broader area in T1-weighted MR images than on T images.. The signal intensities on both sides of the basal ganglia decrease slightly on MR images. D. Decreased signals appear on both sides of the basal ganglia on fluid attenuated inversion recovery T2-weighted MR images. 파겔은수분을함유함과동시에시약들이가라앉지않게하기위하여사용되었다. 농도는시약의무게를전체부피로나눈 g/ml 를사용하였고농도의범위는시약이함유되지않은대조표준 (0) 에서 0.01, 0.02, 0.05, 0.1, 0.2, 0.5 g/ml 으로하여각각을유리용기에담아 T와 MRI 영상을얻었다. 이후에인산칼슘만대조표준, 0.1, 0.2, 0.3, 0.4, 0.5 g/ml 의농도로만들어 MRI 영상을얻었다. 실험에서 T (prospeed, GE, US) 는집단별로촬영하여그밀도를측정하였고, MRI (magnum 1.0, medison, Korea) 는 T1 강조영상 (spin echo sequence, TR 450 ms, TE 12.7 ms), T2 강조영상 (fast spin echo sequence, echo train length 12, TR 4400 ms, TE 108 ms) 과 FLIR 영상 (fast spin echo sequence, echo train length 8, TR 9000 ms, TI 2200 ms, TE 96 ms) 을얻어각각의상대명암도를측정하였다. T 와 MRI 는모두 3회측정하여그평균값을사용하였다. Figure 2. 29-year-old man with Down s syndrome (case 2).. Layered high densities are seen on both sides of the basal ganglia on T images without contrast enhancement.. The high signals are less obvious on T1-weighted MR images than on T.. Weak low signals are seen on T2-weighted MR images. D. Relatively prominent low signals are seen on fluid attenuated inversion recovery MR images. 결과 뇌 T 에서양측바닥핵에고밀도의석회화를보인 2명중첫증례는부갑상샘기능저하증으로확인된 30세여자였고, 두번째증례는다운증후군환자로양측에미성숙바닥핵석회화를보인 29세남자였다. 이들은모두 T에서는양측바닥핵에고밀도가있었고, MRI T1 강조영상에서는고신호강도, T2강조영상과 FLIR 영상에서는저신호강도를보였다. 그러나첫증례에서는 T 의고밀도보다 T1 강조 MRI 에서고신호강도의범위가더넓고뚜렷했으며, T2 강조영상과 FLIR 영상에서보이는저신호는이보다는뚜렷하지않았다 (Fig. 1). 두번째증례에서는 T의고밀도보다 T1 강조 MRI 의고신호강도가뚜렷하지않았으나, FLIR 영상에서뚜렷한저신호강도를보였다 (Fig. 2). 인산칼슘, 탄산칼슘과수산기인회석을각농도별로만든후촬영한 T 에서 (Fig. 3) 이들각각의밀도는농도에따라증가하였으며석회화의종류에의한차이는크지않았다 (Fig. 4). 인산칼슘, 탄산칼슘과수산화칼슘을각농도별로만든후촬영한 MRI 영상에서는 T1 강조영상에서인산칼슘은농도가증가함에따라신호가증가하였으나탄산칼슘과수산기인회석 J Korean Neurol ssoc Volume 27 No. 2, 2009 159
최영칠신현준최진영 Figure 4. graph based on different T densities. Their densities increased in proportion to the concentrations do not correspond to the types of calcification. Figure 3. T images of calcium suspensions with different concentrations. The upper left corner is the hydroxylapatite group, the right side is the calcium carbonate group, and the bottom is the calcium phosphate group, arranged from the top left to the bottom right, with concentrations of 0 g/ml, 0.01 g/ml, 0.02 g/ml, 0.05 g/ml, 0.1 g/ml, 0.2 g/ml, and 0.5 g/ml. 은큰변화가없었다 (Fig. 5). T2 강조영상에서인산칼슘은 0.1 g/ml 까지는신호가약간증가하나그후는감소경향이있었고, 탄산칼슘은뚜렷한변화가없었으며, 수산기인회석은농도의증가에따라신호가감소하는경향이확실했다. FLIR 영상에서는 T2 강조영상에서보였던양상이더뚜렷하게나타났다 (Fig. 6). 두번째실험의결과로이전실험의 MRI 에서일정한경향의신호를보였던인산칼슘을일정간격의농도로만들어서얻은 MRI (Fig. 7) 에서인산칼슘은 T1 강조영상에서 0.2 g/ml 까지 신호의증가가뚜렷하고. 그이후는비슷한고신호강도를유지하였으며, T2 강조영상과 FLIR 영상에서는 0.1 g/ml 이후농도의증가에따라신호의감소경향이뚜렷하였다 (Fig. 8). 고찰 MRI T1 강조영상에서두개내석회화가고신호강도를보인다는보고와실험들은이전부터있었다. Dell 등은가성부갑상샘기능저하증환자의 MRI T1 강조영상에서바닥핵에고신호강도가보이는석회화를갖는경우를보고하고인산칼슘의현탁액을사용한실험모형에서농도가증가함에따라 T1 및 T2 이완시간이감소한다고하였다. 1 또한 Henkelman 등은뇌조직에 MRI T1 강조영상에서고신호강도를보이는석회화침착이있는경우들을제시한후, 미립자로된수산화인회석과탄산칼슘을다양한농도로만들어 T1과 T2 이완성과표면적을구하여표면적이큰석회화입자가큰 T1 이완성을보이고 T2는감소하였으 Figure 5. MR images of calcium suspensions with various concentrations arranged in the same sequence as Figure 3.. T1-weighted images of the calcium phosphate group show a distinct high signal at higher concentration.. T2-weighted images show that the signal decreases as the concentration increases in the hydroxylapatite group. The rest shows low signals at higher density.. Fluid attenuated inversion recovery images show a clear decrease of signals as the concentration increases in the hydroxylapatite and calcium carbonate groups. low signal is also observed with the calcium phosphate group with a high concentration. 160
Figure 7. MR images of the calcium phosphate suspensions from concentrations of 0.1, 0.2, 0.3, 0.4, and 0.5 g/ml. T1-weighted images are on top, T2-weighted images at the bottom left, and fluid attenuated inversion recovery images at the bottom right. Figure 6. Relative signal intensities of different concentrations on MRI.. graph of relative signal intensity on T1-weight MR images.. graph of relative signal intensity on T2-weight MR images.. graph of relative signal intensity on fluid attenuated inversion recovery MR images. 며, 칼슘입자의농도가무게의 30% 까지 T1 강조영상에서신호가증가하고그후는감소한다고하였다. 2 oyko 등은신경영상에서메트헤모글로빈과관계없는 T1 감소는석회화와대뇌경색의층상괴사에서관찰된다고하였다. 3 그후 vrahami 등은 Fahr 병환자 32명의뇌 T 와 MRI 를비교하여 25명은 T 에서석회화를보이는부위들이 T1 강조 MRI 에서는고신호강도, T2 강조영상에서는저신호또는동등신호강도를보인다고하였으며, 이는석회화결정의표면에근접해있는수소양자의 T1 이완시간의감소에의한다고하였다. 4 그러나 Tenner 등은석회화된뇌수막종과칼슘수산화인회석현탁액으로연구를하여석회화된수막종의 T1 단축은출혈이있는경우라고하였다. 5 Figure 8. Relative signal intensities of calcium phosphate suspensions with different concentrations. On T1-weighted MR images, the signal of calcium phosphate increased up to the concentration of 0.2 g/ml before leveling off, whereas the signal clearly decreased gradually on T2-weighted and FLIR MR images. 이후로두개내석회화는 T1 강조 MRI 에서흔하지않게고신호강도를유발하는병변으로보고되었다. 6-9,10,11 이들은모두이전의연구 1-4 에이론적바탕을둔것으로더이상의실험적연구나새로운사실의제안은찾을수없었다. 저자들의연구에서세가지의석회화를각각일정한농도별로만든현탁액으로 T와 MRI 를하여석회화는종류에큰관계없이농도가증가하면 T에서밀도가증가하나 MRI 에서는종류나농도에따라서다양하게나타나며일정농도이상에서는 T1 강조영상에서고신호강도를, T2 강조영상이나 FLIR 영상에서는저신호강도가나타나는것을확인하였다. 석회화의종류에관계없는 MRI 소견은 FLIR 영상에서농도의증가에따라신호강도가감소하는것이다. 그리고 T1 강조영상에서고신호강도를보이는것이가장눈에띄는소견으로, J Korean Neurol ssoc Volume 27 No. 2, 2009 161
최영칠신현준최진영 인산칼슘의농도가증가함에따라신호강도가증가하였으나, 0.2 g/ml 이상에서는거의비슷한고신호강도를보였다. 또한이경우 T2 강조영상과 FLIR 영상에서는농도가증가함에따라신호강도가감소하였다. 결론적으로석회화는 T에서는종류에관계없이농도의증가에따라고밀도로나타나나, MRI 에서는종류나농도에따라다양하게나타나고그중 FLIR 영상에서농도에따른신호강도의감소가거의일정한소견이며, 종류와농도에따라 T1 강조영상에서고신호강도를보이는경우가있음을알수있었다. 상기결과는 MRI 에서석회화의평가에도움을줄수있을것으로생각한다. REFERENES 1. Dell L, rown MS, Orrison WW, Eckel G, Matwiyoff N. Physiologic intracranial calcification with hyperintensity on MR imaging: case report and experimental model. JNR m J Neuroradiol 1988;9:1145-1148. 2. Henkelman RM, Watts JF, Kuchatczyk W. High signal intensity in MR images of calcified brain tissue. Radiology 1991;179:199-206. 3. oyko O, urger P, Shelburne JD, Ingram P. Non-heme mechanisms for T1 shortening: pathologic, T and MR elucudation. JNR m J Neuroradiol 1992;13:1439-1445. 4. vrahami E, ohn DF, Feibel M, Tadmor R. MRI demonstration and T correlation of the brain in patients with idiopathic intracranial calcification. J Neurol 1994;241:381-384. 5. Tenner MS, Spiller M, Koenig SH, Valsamis MP, hildress S, rown RD 3rd, et al. alcification can shorten T2, but not T1, at magnetic resonance imaging fields. Results of a relaxometry study of calcified humen menigioma. Invest Radiol 1995;30:345-353. 6. Go JL, Zee S. Unique T imaging advantages. Hemorrhage and calcification. Neuroimaging lin N m 1998;8:541-558. 7. aruso RD, Postel G, McDonald S, Sherry RG. High signal on T1-weighted MR imagines of the head: a pictoral essay. lin Imaging 2001;25:312-319. 8. akirer S, Karaarslan E, rslan. Spontaneously T1-hyperintense lesion of the brain MRI: a pictoral review. urr Probl Diagn Radiol 2003; 32:194-217. 9. Warakaulle DR, nslow P. Differntial diagnosis of intracranial lesions with high signal on T1 or low signal on T2-weighted MRI. lin Radiol 2003;58:922-933. 10. Suzuki S, Nishio S, Takata K, Morioka T, Fukui M. Radiation-induced brain calcification: paradoxical high signal intensity in T1-weighted images. cta Neurochir (Wine) 2000;142:801-804. 11. hn JH, Yoo I, Lee R, Lee JH, Lee H, Kim Y, et al. alcification mimicking manganese-induced increased signal intensity in T1-weighted MR images in a patient taking herbal medicine: case report. Neurotoxicology 2003;24:835-838. 162