The Incidence and Anatomy of Accessory Pudendal Arteries as Depicted on Multidetector-Row CT Angiography: Clinical Implications of Preoperative Evaluation for Laparoscopic and Robot-Assisted Radical Prostatectomy

OBJECTIVE: To help preserve accessory pudendal arteries (APAs) and to ensure optimal postoperative sexual function after a laparoscopic or robot-assisted radical prostatectomy, we have evaluated the incidence of APAs as detected on multidetector-row CT (MDCT) angiography and have provided a detailed anatomical description. MATERIALS AND METHODS: The distribution of APAs was evaluated in 121 consecutive male patients between February 2006 and July 2007 who underwent 64-channel MDCT angiography of the lower extremities. We defined an APA as any artery located within the periprostatic region running parallel to the dorsal vascular complex. We also subclassified APAs into lateral and apical APAs. Two radiologists retrospectively evaluated the origin, course and number of APAs; the final APA subclassification based on MDCT angiography source data was determined by consensus. RESULTS: We identified 44 APAs in 36 of 121 patients (30%). Two distinct varieties of APAs were identified. Thirty-three APAs (75%) coursed near the anterolateral region of the prostatic apex, termed apical APAs. The remaining 11 APAs (25%) coursed along the lateral aspect of the prostate, termed lateral APAs. All APAs originated from the internal obturator artery and iliac artery or a branch of the iliac artery such as the inferior vesical artery. The majority of apical APAs arose from the internal obturator artery (84%). Seven patients (19%) had multiple APAs. CONCLUSION: APAs are more frequently detected by the use of MDCT angiography than as suggested by previous surgical studies. The identification of APAs on MDCT angiography may provide useful information for the surgical preservation of APAs during a laparoscopic or robot-assisted radical prostatectomy.

Non-Calcified Ductal Carcinoma in Situ: Ultrasound and Mammographic Findings Correlated with Histological Findings

PURPOSE: To evaluate radiological findings of non-calcified ductal carcinoma in situ (DCIS) and to correlate those with histological features. MATERIALS AND METHODS: From July 2002 to March 2006, 22 patients with histologically-proven non-calcified DCIS were included. Mammography was obtained in 19 patients, ultrasound in 18 patients, and both examinations in 15 patients. Radiological findings were evaluated according to the Breast Imaging Reporting and Data System by American College of Radiology. Histological tumor subtype and Van Nuys classification of DCIS were assessed. RESULTS: Histological subtypes consisted of mixed type in 11 patients (50%), comedo in 4 (18%), cribriform in 4 (18%), papillary type in 2 (9%), and solid in one (5%). According to Van Nuys classification, group 3 DCIS was observed in 13 (59%) patients. In the 19 patients who underwent mammography, 13 patients presented with abnormal findings: focal asymmetry in 7 patients (37%), masses in 4 (21%), skin thickening in one (5%), and architectural distortion in one (5%). In the 18 patients who had received breast ultrasound, a mass was present in 15 (83%) patients and ductal changes in 3 patients (17%). Sixty percent of patients with masses on ultrasound had group 3 DCIS and 100% of patients with ductal change had group 1 DCIS (p=0.017). CONCLUSION: Diagnosis of non-calcified DCIS by mammography is not an easy task due to the lack of typical malignant calcifications or masses. High resolution ultrasound can be useful for detecting non-calcified DCIS, and ultrasound findings are correlated with histological features.

Tuberculous Spondylitis vs Pyogenic Spondylitis: Focusing on the Discriminative MR Findings for Differentiation

PURPOSE: The purpose of this study is to analyze the most discriminative MR findings for making the differential diagnosis of tuberculous and pyogenic spondylitis. MATERIALS AND METHODS: Sixty MR scans of 18 pyogenic spondylitis patients and 42 tuberculous spondylitis patients were retrospectively reviewed. The statistical analysis was performed using stepwise discriminant analysis and Student's T-test. RESULTS: The patients with tuberculous spondylitis had a significantly higher incidence of MRI findings as follows (p <0.05): smooth margin of a paraspinal mass/abscess in 67% [28/42] of the tuberculous spondylitis patients vs 6% [1/18] in the pyogenic spondylitis patients, mild endplate erosion in 52% [22/42] vs 38% [7/18], respectively, the presence of paraspinal mass/abscess in 100% [42/42] vs 6% [1/18], respectively, central dark signal intensity of the abscess in 86% [36/42] vs 39% [7/18]), respectively, subligamentous spread in 81% [34/42] vs 50% [9/18]), respectively, severe vertebral collapse in 20% [8/42] vs 11% [2/18]), respectively, and posterior extension in 62% [26/42] vs 33% [6/18]), respectively. Among of them, the significant discriminative MR findings were the margin of a paraspinal mass, the grade of endplate erosion and the presence or absence of a paraspinal mass in that order. CONCLUSION: In the differentiation of tuberculous and pyogenic spondylitis, the margin of the paraspinal mass, the grade of endplate erosion and the presence or absence of a paraspinal mass are the most three discriminating MR findings in that order.

A Comparative Study of Breast Cancer of Korean Women according to Age in Radiological, Pathological, and Clinical Findings / 한국유방암학회지

PURPOSE: The incidence of breast cancer is continuously increasing in Korea, and the age of the initially detected breast cancer is younger than western people. The purpose of this study was to compare radiological, pathological, and clinical findings of breast cancers according to age and then contribute to the basis of screening program of breast cancer. METHODS: Retrospectively, the 325 patients who had pathologically confirmed breast cancer were included in this study. The patients were classified into 6 groups according to age, 20~29, 30~39, 40~49, 50~59, 60~69, and more than 70 years. We evaluated the radiological findings of 325 cases of mammography and 144 cases of breast ultrasonography, classified as four types; mass, microcalcification, others, and non-detected lesion, and then analyzed radiological findings according to age. We evaluated pathological and clinical findings according to age and compared with radiological findings. We used Mantel-Haenszel's chi 2 test and trend test for comparison according to age. RESULTS: The incidence of breast cancer was 61 cases (19%) in 30~39 years, 122 (38%) in 40~49 years, 92 (28%) in 50~59 years. Most of breast cancer was invasive ductal carcinoma, 258 (79%) and in situ carcinoma was 32 (10%). Most of in situ carcinoma was detected in 20~59 years, 31/32 (97%). Mammography showed mass in 237 (73%), microcalcification in 45 (14%), other finding in 13 (4%), and non-detected lesion in 30 (9%). Twenty-one (47%) of 45 cases with microcalcification were in situ carcinoma and most of in situ carcinoma was presented as microcalcification on mammography, 21/32 (66%). In twenty-eight of 30 cases (93%) with non-detected lesion on mammography, breast cancer was detected on ultrasonography. In terms of clinical findings, there was no symptom in 12/32 (38%) with in situ carcinoma and 57/258 (22%) with invasive ductal carcinoma. CONCLUSION: The incidence of breast cancer is abruptly increasing from 4th decades and there is no significant difference in radiological and clinical findings according to age. But, most of in situ carcinoma was detected in 20~59 years and presented as microcalcification on mammography. Thus, Screening mammography should be considered from 4th decades.

Spiral CT Findings of Chromophobe Renal Cell Carcinoma: Correlation with Pathologic Features and Prognosis

PURPOSE: To describe the spiral CT findings of CRCC and to correlate these with the pathologic features, nuclear grading, tumor staging, and prognosis. MATERIALS AND METHODS: We encountered eleven cases of CRCC among 167 cases of histopathologically proven RCC, retrospectively evaluating the spiral CT findings of CRCC including tumor size, internal texture, attenuation, margin, and the involvement of veins or lymph nodes. In addition, the CT findings were correlated with the pathologic features, Fuhrman's nuclear grade, Robson's staging, and the prognosis. Between 27 and 80 (mean, 49.6) months later, the follow-up CT scans of tea patients were examined for tumor recurrence. RESULTS: All tumors, which ranged in size from 2.5 to 15 (mean, 7.7) cm, were solid and well demarcated from renal parenchyma. Pre-contrast CT scans showed that their attenuation was equal to (n=1) or slightly lower (n=10) than that of renal parenchyma, and on early and delayed phase post-contrast enhanced scans, attenuation was low in all cases. In three, focal areas in which attenuation was lower than in the rest of the tumor were observed; histopathologically, these represented hyalinization. There was neither venous nor lymph node involvement, and no distant metastasis. Histopathologic examination demonstrated cystic change (n=1), hemorrhage or necrosis (n=5), complete encapsulation (n=3) and perirenal fat infiltration (n=3). Nuclear grading was II (n=6) or III (n=5), and tumor staging was I (n=8) or II (n=3). Among the five cases in which the nuclear grade was III, three were stage I and two were stage II. Follow-up scans showed no evidence of tumor recurrence, and all patients survived. CONCLUSION: Pre-, early- and late-phase post-contrast enhonced spiral CT scans showed that the attenuation of a CRCC was lower than that of renal parenchyma. Even where the nuclear grade was higher, a well-demarcated soild mass was observed, the tumor stage was lower and the prognosis better.

Hepatocellular Carcinoma: Comparison Study on Detecting Tumor Vascularity among Various Imaging Techniques

PURPOSE: To compare the detectability of tumor vascularity using triphasic spiral CT, angiography, CT during hepatic arteriography(CTHA) and single-level dynamic CTHA(SLD-CTHA). MATERIALS AND METHODS: Seventy-nine pathologically confirmed nodular hepatocellular carcinomas(HCCs) in 77 patients were included in this study. Sixty patients were male and 17 were female, and their ages ranged from 31 to 77 (average, 57.4) years. HCCs were classified into three groups according to the size: less than 2 cm (n=20), 2 -4 cm (n=32), and more than 4 cm (n=27) in diameter. If a portion of tumor demonstrated greater enhancement than surrounding liver parenchyma, vascularity was deemed to be present. Detectability by each imaging technique was compared according to size and overall. RESULTS: Hypervascularity was frequently detected by SLD-CTHA [90.9%(40/44)], followed by CTHA[88.0%(66/75)], angiography [80.3%(61/76)], triphasic spiral CT [72.4%(42/58)]. In the less than 2 cm group, detectability rates for triphasic spiral CT, angiography, CTHA and SLD-CTHA were 53.3%(8/15), 55.6%(10/18), 76.5%(13/17) and 87.5%(6/7), respectively. while the 2 -4 cm group demonstrated corresponding figures of 71.4%(15/21), 78.1%(25/32), 84.4%(27/32) and 86.4%(19/22). In the more than 4 cm group, the rate for triphasic spiral CT was 86.4%(19/22), while for angiography, CTHA and dynamic CTHA, it was 100%. CONCLUSION: In the detection of hypervascularity of HCC, SLD-CTHA showed the highest rate, followed by CTHA, angiography, and triphasic spiral CT. In HCCs less than 4 cm in diameter, the corresponding ordering was SLD-CTHA, CTHA, angiography and triphasic spiral CT, but in HCCs of more than 4 cm, angiography, CTHA and SLD-CTHA detected hypervascularity equally well. Lesion size most affected the findings of angiography.

CT Staging of Renal Cell Carcinoma Using the Revised 1997 TNM Staging Criteria: In Comparison with the Previous One

PURPOSE: To assess the accuracy of preoperative CT staging of RCC and to compare the relationship between T stage and the incidence of metastasis on the basis of the old (1992) and the new (1997) UICC & AJCC tumor classification system. MATERIALS AND METHODS: In 112 cases of surgically resected RCC, the stagings of preoperative CT scans were de-termined retrospectively by two radiologists and were compared with the results of pathologic examinations. In 70 cases which had been followed up over three years after surgery, the incidence of metastasis at initial diagnosis and during the follow-up period was assessed. All cases were reconsidered, and using the old and the new TNM classification, the incidence of metastasis was compared. RESULTS: According to the old TNM classification, 5 cases (4%) were staged at T1, 73(65%) at T2, 21(19%) at T3a, 9(8%) at T3b, 0 at T3c, and 4(4%) at T4. Using the new TNM classification, we also staged 54 cases (48%) at T1 and 24(21%) at T2. Overall, using this new classification, CT correctly staged 79% of patients (88/112) overstaged 15%(17/112) and understaged 6%(7/112) . CT had a sensitivity of 84% and specificity of 91% in new T1 tumors, 71% and 95%, respectively, in new T2 tumors, 69% and 88% in T3a tumors, 78% and 98% in T3b tumors, and 75% and 99% in T4 tumors. CT had a sensitivity of 44% and a specificity of 99% in old T1 tumors, and 82% and 71%, respectively, in old T2 tumors. The incidence of metastasis in CT-staged (cT) tumors was 0% (0/4) in old cT1, 8% (3/39) in new cT1, 29% (4/14) in new cT2, 67% (6/9) in cT3a, and 75% (6/8) in cT3b. CONCLUSION: In the staging of T1 tumors, CT is more sensitive when the new TNM classification is used. Even though the cut off point between T1 and T2 tumors had been in creased from 2.5 to 7.0 cm, T1 tumors staged according to the new system did not show a significantly higher incidence of metastasis than those staged according to the old.

Preoperative CT Assessement of Esophageal Carcinoma: Comparison between the Patients with and without Recurrence of Esophageal Carcinoma after Surgical Resection

PURPOSE: To determine whether preoperative CT is helpful in predicting the development of recurrent tumor following surgical resection in patients with esophageal cancer. MATERIALS AND METHODS: Thirty patients with esophageal cancer in whom preoperative CT of the chest had been performed were included in the study. All had undergone esophagectomy, esophagogastrostomy and lymph node dissection at our institution between 1995 and 1997. They were divided into two groups according to the development of tumor recurrence during the follow-up period of three years. Sixteen patients (group I) suffered tumor recurrence, while the other 14 (group II) remained tumor-free after surgery. In each group, a review of the preoperative CT scans indicated the length, thickness, location and margin of the tumor, and the presence or absence of lymphadenopathy in the mediastinum and/or upper abdomen. Differences in preoperative CT findings between the two groups were assessed by statistical testing. RESULTS: Lymphadenopathy of the mediastinum and/or upper abdomen was seen in 11 (69%) of 16 patients in group I and three (21%) of 14 in group II (p.05). In group I, five esophageal tumors were located in the middle esophagus and eleven in the lower esophagus. In group II, such tumor was located one in the upper esophagus, six in the middle esophagus, and seven in the lower esophagus (p>.05). CONCLUSION: Patients with preoperative CT findings of lymphadenopathy and/or an indistinct primary tumor margin are more likely to develop tumor recurrence following surgical resection than those without these findings.

Nodular Hepatocellular Carcinoma: Findings of Single-Level Dynamic CT During Hepatic Arteriography

PURPOSE: To evaluate the hemodynamics of nodular hepatocellular carcinoma (HCC) using single-level dynamic CT during hepatic arteriography (CTHA) according to the size of the nodule. MATERIALS AND METHODS: Forty 40 patients with nodular HCC confirmed histologically or radiologically underwent single-level dynamic CTHA. Contrast media was injected via the hepatic artery for 20 seconds at a rate of 1.2 ml/sec. Images were obtained prior to this and thereafter at 3-second intervals until 30 seconds after the start of injection, and additional images at 45 and 60 seconds. The CTHA findings were retrospectively reviewed, and cases were assigned to one of three groups, according to the size of the tumor [ 5 cm (group III, n =16)]. We focused on onset time of contrast enhancement (CE), peak CE time and density, and duration of plateau. The patterns of CE were classified as homogeneous, heterogeneous, peripheral, or "nodule in nodule ". RESULTS: The onset time of CE was 3 seconds and mean peak CE time was 18.8 seconds. A plateau was noted in all groups (mean duration, 6.8 seconds). Mean peak CE time and density were 16.5 seconds and 294.1 HU in group I, 18.5 seconds and 324.1 HU in group II, and 20.1 seconds and 114.0 HU in group III. The most frequent pattern of CE (83%) was homogeneous, and this was found in group I. The small HCC group (group I) showed a faster mean peak CE time than the large group (group III) (p < 0.05), and this latter showed a lower peak CE density than the other groups (p < 0.05). In groups II and III, "nodule in nodule "(72%) and heterogeneous patterns (69%) were, respectively, the most frequent findings. CONCLUSION: Single-level dynamic CTHA is useful in evaluating the hemodynamics of HCC.

What is the Best MR Sequence to Evaluate

PURPOSE: To determine the best MR sequence for evaluation of the anatomical structures of normal kidney. MATERIALS AND METHODS: Twenty normal volunteers (M:F=15:5) took part in this study, and for each, seven sequences were performed. The T1 weighted sequences were conventional spin echo T1 (Conv-SET1), turbo spin echo T1 (TSET1), and fast low angle shot (FLASH), while the T2 weighted sequences were turbo spin echo T2 (TSET2), half-Fourier acquisition single-shot turbo spin echo (HASTE), true-fast imaging with steady-state precession (True-FISP), and echoplanar imaging (EPI). The study involved quantitative and qualitative analysis. In quantitative analysis, CNRs between cortex and adjacent fat tissue, and between cortex and medulla were calculated from SNR (signal to noise ratio), and the CNRs of sequences were statistically compared. In quantative analysis, three radiologists collectively evaluated kidney outline, corticomedullary division, the renal vessels, the pelvis/ureter, and artifacts. For each sequence a grade was assigned, and for each parameter the grades were compared. RESULTS: Between cortex and adjacent fat, the highest CNR was shown by TSET1, followed by Conv-SET1,while among T2 sequences, the CNR shown by TSET2 was highest. Between cortex and medulla, the CNR demonstrated by the three T1 sequences showed no statistically significant difference. Among T2 sequences, however, HASTE showed the highest CNR, followed by EPI, and statistically, the findings for these two were significantly different from those of other T2 sequences. Among T1 sequences, FLASH provided the best kidney outline, though among T2-sequences there was no statistically significant difference. FLASH was also the best for cortico-medullary distinction, while for this purpose the best T2 sequence was HASTE. True-FISP was best for the evaluation of renal vessels, and HASTE for evaluating the pelvis and ureter. Artifacts were most prominent on Conv SET1. CONCLUSION: For evaluating the shape of the kidney, the best T2 sequence was TSET2, but the best T1 sequence could not be determined. For cortico-medullary differentiation, the best T1 sequence was FLASH and the best T2 sequence was HASTE. For the evaluation of renal vessels, True-FISP was best, and for the pelvis and ureter, HASTE. Artifacts were most prominent on Conv-SET1.

In Vitro of MR Imaging of the Resected Normal Gastric Wall: Radiologic-Histologic Correlation

PURPOSE: To evaluate normal human gastric wall layers in vitro using magnetic resonance*(MR) imaging, to correlate the results with the histologic findings, and to determine the optimal technique for evaluation of the gastric wall. MATERIALS AND METHODS: Forty-one normal resected gastric specimens obtained from 25 patients were dissected and placed in a polyethylene tube filled with normal saline. MR imaging with four MR sequences, T1-weighted FLASH*(T1FLASH), fat-saturated T1-weighted FLASH, T2-weighted TSE*(T2TSE), and True-FISP, was performed. The number of gastric wall layers and signal intensity of each layer were determined, and after correlating MR images with the histologic findings, the conspicuity of each layer*(mucosa, submucosa, and muscle), the distinction between each layer, and overall image quality were assessed. RESULTS: The gastric wall was shown by TIFLASH to have two (n=6, 14-6%), three (n=31, 75.6%) and four layers (n=4, 9.8%); by fat-saturated TIFLASH to have two (n=6, 14.6%) and three (n=35, 85.4%) ; by T2TSE to have three (n=24, 58.5%), four (n=11, 26.8%), and five (n=6, 14.6%); and by True-FISP to have one (n=2, 4.9%), two (n=8, 19.5%), three (n=23, 56%), four (n=4, 9.8%), and five (n=4, 9.8%) . The signal intensity of each layer at T1FLASH and fat-saturated T1FLASH was high-intermediate from the lumen in two-layer cases, high-low-high/intermediate in three-layer cases, and high-low-high-intermediate in four-layer cases. The signal intensity of each layer at T2TSE was intermediate/high-low-intermediate in three-layer cases, intermediate low-high-intermediate/low in four-layer cases, and low-high-low-high-low in five-layer cases. Three-layered gastric wall corresponded mostly to mucosa, submucosa, and muscle from the inner to outer layers, respectively. T1FLASH, fat-saturated T1FLASH, and T2TSE were superior to True-FISP in evaluating the gastric wall. T1FLASH and fat-saturated T1FLASH were the best sequences for demonstrating mucosa (p<0.05), and T2TSE was the best for submucosa and the distinction between this and muscle (p<0.05). Both T1FLASH and T2TSE provided the best overall image quality (p<0.05). CONCLUSION: In-vitro MR imaging is an excellent technique for the evaluation of layers of normal gastric wall. T2TSE is the sequence which best demonstrates the conspicuity of submucosa, the distinction between submucosa and muscle, and overall image quality.

Pseudolesions around the Gallbladder Fossa: Comparison of Frequency and Radiological Characteristics in Multiphasic CT, CTAP, and CTHA

PURPOSE: The purpose of this study is to compare the frequency with which pseudole-sions around the gallbladder (GB) fossa are revealed by multiphasic CT, by CT during arterial portography (CTAP), and by CT during hepatic arteriography (CTHA) and to determine their radiological characteristics. MATERIALS AND METHODS:Multiphasic CT, CTAP, and CTHA examinations of 81 patients without pathology of the GB and around the GB fossa were evaluated for pseudolesion around the GB fossa. The definition of pseudolesion was as follows: 1) hyperattenuation during the arterial phase and isoattenuation during the delayed phase of multipha-sic CT, or perfusion defect on CTAP and hyperattenuation on CTHA; 2) no Lipiodol tagging on Lipiodol CT; 3) all findings observed adjacent to the gallbladder fossa; and 4) no interval change on follow-up CTAP and CTHA. We compared the frequency of pseudolesions around the GB fossa, as seen on multiphasic CT, CTAP, and CTHA, and determined their size, location, and shape, as revealed by CTHA. RESULTS: The frequency of pseudolesion was 2.5% (2/81) on multiphasic CT, while on CTAP or CTHA, the frequency was 53.1% (43/81), and 58 pseudolesions were identi-fied. Of 58 pseudolesions, 56 were revealed by CTAP and 57 by CTHA. Forty-nine of 58 pseudolesions were larger and all pseudolesions showed more contrast to parenchyma on CTHA than on CTAP. The location of pseudolesions was segment V(32 of 58), IV (25 of 58), and VI (1 of 58), and their size ranged from 5 to 30 (mean, 17.5)mm. Pseudolesions were wedge-shaped (48 of 58), oval (6 of 58), bandlike (3 of 58), or round (1 of 58). CONCLUSION: CTAP and CTHA frequently revealed pseudolesion around the GB fossa. The radiological characteristics of these modalities help differentiate pseudolesions from true tumoral hepatic lesions.

Opacification of Portal Vein on CT during Hepatic Arteriography Via Normal Vascular Flow

PURPOSE: To evaluate the frequency, distribution, and associated factors of the opacified normal portal veinas seen on CT, during hepatic arteriography(CTHA). MATERIALS AND METHODS: One hundred and eighty-nine patientswho underwent both CTHA and CT during arterioportography (CTAP) during a three-year period were reviewed. Ofthese, 66 patients without anomalous hepatic arterial supply and arterioportal (AP) shunt on celiac angiographywere analyzed. Comparing CTHA with CTAP, we determined whether or not the portal vein(PV) is opacified within thesecond-order branch. The degree of contrast enhancement in the stomach, duodenum, and pancreas was graded asfollows : grade I, all three organs were hypodensely enhanced; grade II, some organ were isodensely enhanced, butothers hypodensely ; grade III, all three organs were isodensely enhanced relative to the CHA. The relationshipbetween opacified portal vein (OPV) and the degree of enhancement of the three organs, amount of contrast media,and Child classification was statistically examined. RESULTS: The PV was opacified in 18 of the 66 patients (27%); This was the main PV in 16, right PV in 13, and left PV in two. Of the single branches, the right post posteriorbranch was most commonly opacified. Among 18 patients with OPV, the degree of three organs (stomach, duodenum, andpancreas) was grade I in two, grade II in two, and grade III in 14 while among 48 patients with nonopacified PV, thefindings were grade I in 27, grade II in seven, and grade III in 14. The relationship between OPV and degree ofenhancement of the three organs was statistically significant (p=0.001). There was however, no statisticallysignificant difference between OPV and Child classification and the amount of contrast media. CONCLUSION: PVopacification during CTHA is not rare and this finding should not therfore be regarded as indicator of apathologic conditions such as AP shunt.

Zebra Pattern in CT during Arterial Portography: Analysis of Associated Factors

PURPOSE: To analyze the factors associated with the zebra pattern in CT during arterial portography(CTAP). MATERIALS AND METHODS: In 275 CTAP procedures, the factors associated with the zebra pattern, such as laminar flow in the portal vein, the presence of liver cirrhosis, the artery selected for CTAP, location of the catheter tip in the superior mesenteric artery(SMA), splenic volume, and the existence of an aberrant right hepatic artery(RHA) emerging from the SMA were analyzed. RESULTS: In 106 of 275 procedures (38.5%), a zebra pattern was apparent. Portal venous laminal flow was seen in 92 % of procedures in the group with this pattern and in 63 % in the group without it. Eighty-three of 235 procedures (35.3 %) in which the SMA was injected and 23 of 40(57.5 %) involving splenic artery injection showed the zebra pattern. In 22 of 35(62.8 %) in which the catheter tip was located in the distal SMA and 61 of 200 ( 30.5 %) in which this was at a proximal site, the zebra pattern was evident. Mean splenic volume was less in the group with the zebra pattern. The effect on the zebra pattern of liver cirrhosis and an aberrant RHA emerging from the SMA was not statistically significant. CONCLUSION: In CTAP, the incidence of the zebra pattern was 38.6%, and was related to laminal flow in the portal vein. The pattern is frequently seen in CTAP involving contrast injection via the splenic artery, distal location of a catheter tip in the SMA, and small splenic volume.

An Experimental Study on the Effect of Mixture of Absolute Ethanol and Lipiodol Injected into Normal Liver ofRabbit: CT Features and Histopathologic Changes

PURPOSE: To investigate the safety and usefulness of Lipiodol-percutaneous transhepatic ethanolinjection(L-PEI) and to determine the appropriate concentration of Lipiodol during L-PEI. This was achieved byevalvating CT findings and histopathologic changes according to the concentration of Lipiodol, amount of ethanol,and the time interval after injection into normal rabbit liver. MATERIALS AND METHODS: This experimental studyinvolved 18 New Zealand rabbits under US guidance. They were divided into five groups according to injectedmaterials; two rabbits with 0.4cc of normal saline(group I), six with 0.4cc of ethanol in the left hepaticlobe(group II), and 0.4cc of Lipiodol in the right hepatic lobe(group III), five rabbits with 5%Lipiodol-ethanol(5% vol. of Lipiodol+95% vol. of ethanol), 0.2cc in the right hepatic lobe, and 0.4cc in theleft(group IV); and five rabbits with 10% Lipiodol-ethanol as per group IV(group V). CT was performed immediately,one week, two weeks, and three-four weeks after injection, and pathologic specimens were obtained on the thirdday(acute phase) and during the third or fourth week(chronic phase) after injection. RESULTS: On CT, intrahepaticlocalization of the L-PEI injection site was well demonstrated as a focal high attenuated area which graduallydecreased in attenuation on follow up CT. The opacification of the inferior vena cava by Lipiodol, the lineardistribution of Lipiodol along portal veins or fissures, and peritoneal leakage were clearly demonstrated ingroups III-V, though the effects gradually disappeared during follow-up CT. There was no remarkable difference ingross CT attenuation between group IV and group V. The main pathologic findings during the acute phase of group IIwere coagulation necrosis surrounded by macrophage, inflammatory reaction, and early periportal and subcapsularfibrosis. The findings in group IV and V were similar to those in group II and additional fat vacuoleaccumulations in the necrotic area were also seen. During the chronic phase of group II, areas of necrosis wereabsent or smaller and were surrounded or replaced by more organized fibrosis, macrophage or multinucleated giantcell infiltration. Periportal, subcapsular fibrosis was also found. In group IV and V, the findings were similarto those of group II, though additional fat vacuoles in fibrotic or necrotic areas, foreign body reaction to fatvacuole, regenerating nodule and calcification were also observed. CONCLUSION: L-PEI is more useful for thedetection by CT of an injection site than PEI alone, and with regard to CT and histopathologic findings, there wasno significant difference between the 5% and 10% Lipiodol-ethanol groups. Compared to PEI, L-PEI provoked nosighificant additional hepatic injury; only fatty change and foreign body reaction were noted. Thus, L-PEI is moreuseful than PEI for the management of HCC.

Borrmann Type IV Adenocarcinoma versus Gastric Lymphoma: Spiral CT Evaluation

PURPOSE: To distinguish the spiral CT findings of Borrmann type IV adenocarcinoma from those of gastric lymphoma with diffuse gastric wall thickening. MATERIALS AND METHODS: We retrospectively reviewed the spiral CT scans of 30 patients with Borrmann type IV adenocarcinoma and nine with gastric lymphoma with diffuse gastric wall thickening. In all patients the respective condition was pathologically confirmed by gastrectomy. CT scanning was performed after peroral administration of 500-700ml of water. A total of 120-140ml bolus of nonionic contrast material was administered intravenously at a flow rate of 3ml/sec and two-phase images were obtained at 35-45 sec(early phase) and 180 sec(delayed phase) after the start of bolus injection. Spiral CT was performed with 10mm collimation, 10mm/sec table feed and 10mm reconstruction. We evaluated the degree and homogeneity of enhancement of thickened entire gastric wall, and the enhancement pattern of gastric inner layer, as seen on earlyphase CT scans. On early and delayed views, the thickness of gastric wall and the presence of perigastric fat infiltration were determined. The enhancement patterns of gastric inner layer were classified as either continuous or discontinuous thick enhancement, thin enhancement, or nonenhancement. RESULTS: The thickness of gastric wall was 1.2-3.5cm(mean 2.2cm) in cases of adenocarcinoma and 1.2-7.6c m (mean 4cm) in lymphoma. Perigastric fat infiltration was seen in 24 patients with adenocarcinoma(80 %) and four with lymphoma(44%). In those with adenocarcinoma, the degree of enhancement of entire gastric wall was hyperdense in fifteen patients(50%) and isointense in eleven (37 %). Seven patients with lymphoma(78 % ) showed hypodensity. In those with adenocarcinoma, continuous thick enhancement of gastric inner layer was seen in 18 patients(60 %) and discontinuous thick enhancement in nine(30%). In lymphoma cases, no thick enhancement was observed. Thin enhancement of gastric inner layer was demonstrated in three patients with adenocarcinoma( 10 %) and two with lymphoma(22 %). In seven patients with lymphoma(78 %), there was no enhancement. CONCLUSION: The following early-phase findings are highly suggestive of gastric lymphoma: a gastric wall thickness of more than 3 cm; no or minimal perigastric fat infiltration, hypodense enhancement of thickened entire gastric wall; and no or thin enhancement of gastric inner layer.

Assessment of Contrast-enhanced 3D Ultrafast Pulmonary MR Angiography Using Test Injection: Comparison betweenSingle Dose and Double Dose

PURPOSE: Contrast-enhanced 3-D ultrafast MR angiography is a widely accepted MR imaging technique for theevaluation of the carotid artery, aorta, renal artery, mesenteric artery and portal venous system. To esti-mateitsclinical usefulness, single -and double- dose contrast-enhanced 3-D ultrafast pulmonary MR angiography wasassessed after a timing examination was performed. MATERIALS AND METHODS: Twenty volunteers underwentgadolinium-enhanced ultrafast pulmonary MR angiog-raphy( 3-D FISP, TR[msec]/TE[msec]=5.0/2.0, with 25 degrees flipangle). In ten volunteers(single-dose injection group) pulmonary MR angiography was performed after theadminstration of 0.1 mmol/kg(single dose injec-tion group), while the other ten(double-dose injection group) eachreceived, prior to angiography, 0.2 m m o l / kg. In all cases, a timing examination was performed during axialturbo-FLASH imaging(TR/TE/TI=8.5/4.0/100, 1 0 degree flip angle) after injection of the same dose as that used forsubsequent contrast-enhanced pulmonary MR angiography. In both groups, overall image quality, pulmonary arteryvisibility and contrast-to-noise ratio of the pulmonary artery were assessed on the basis of images obtained.RESULTS: With regard to overall image quality, there was no significant statistical difference between the twogroups (P>0.05), and in both, depiction of the central and lobar pulmonary artery was excellent. As regardsdepiction of the segmental artery, the average grading of the single dose injection group was 2.83 +/- 0.32, that ofthe double dose injection group was 2.85 +/-0.3, with no statistical significance(P>0.05). With respect tocon-trast-to-noise ratio of the central, lobar, and segmental arteries, the best results were obtained by thedouble dose injection group(P<0.05). CONCLUSION: Although the contrast-to-noise ratio in the double-dose injectiongroup was better than that in the single-dose group, differences in overall image quality and pulmoanry arterydepiction were not statistically significant. Thus, single-dose, contrast-enhanced 3-D ultrafast pulmonary MRangiography can provide useful images in clinical trials.

Usefulness of Fat-Suppressed Turbo SE MR Imaging for the Evaluation of Meniscal Tears

PURPOSE: Suppression of the relatively high signal intensity of fat leads to more efficient use of thedynamic range for display of tissue contrast. In order to evaluate meniscal tears, we compared a fat-suppressedturbo spin-echo(FSTSE) sequence with turbo SE(TSE). MATERIALS AND METHODS: One hundred and seven knees in 103consecutive patients referred for MR study of the knee were imaged using both FSTSE and TSE sequence. The turbo SEsequence provided proton density-weighted and T2-weighted images (dual echo technique) with an effectiveecho-train length of five. For fat-suppression, a frequency-selective chemical presaturation pulse was applied.Forty-two knees (84 menisci) were studied arthroscopically and the findings were taken as the reference standard.FSTSE and TSE images were reviewed retrospectively by two radiologists. Next, for each patient, the quality ofFSTSE and TSE images was compared;the former were scored by each reviewer as either superior to, equal to, orinferior to TSE images. RESULTS: Among the 214 menisci evaluated, the results of FSTSE and TSE imaging were verysimilar (kappa index 0.87). Twenty four tears were found during arthroscopy in 84 menisci. FSTSE imaging was moresensitive than TSE (96% versus 83%), though specificity was equal(98%). Among the 107 cases, FSTSE images wererated by both observers as superior to TSE images for overall quality and visualization of the meniscus itself.CONCLUSION: For the evaluation of meniscal tears, FSTSE sequences were more sensitive than those obtained withTSE, and their image quality was superior. For the study of meniscus tears among a large population, FSTSE istherefore more useful than TSE.

CT Findings of Tumor and Mature Cystic Teratoma

PURPOSE: A tumor and mature ovarian cystic teratoma rarely coexist, but since it may affect treatment andprognosis, appropriate pre-surgical diagnosis is important. The purpose of this study was to evaluate thedifference in CT findings between a tumor coexisting with a mature ovarian cystic teratoma and a simple matureovarian cystic teratoma. MATERIALS AND METHODS: CT scans of seven cases of tumor coexisting with mature ovariancystic teratoma were reviewed. In each case, size, margin, nature, septation, solid portion, ascites, invasion,and metastasis were analysed. RESULTS: Coexistent tumors were histopathologically diagnosed as squamous cellcarcinoma in three patients, carcinoid in three, and fibrothecoma in one. In contrast with a simple matureteratoma, a tumor coexisting with a mature cystic teratoma developed in older patients and had a more solidportion, which showed contrast enhancement but did not show calcification or a fat component. Where a tumor andmature cystic teratoma coexisted, ascites and the invasion of adjacent structures were also common. CONCLUSION: If, in an older patient, CT scanning reveals an ovarian cystic tumor with a large solid portion but nocalcification or fat, coexistent tumor should be suspected.

CT Features of Malignant Hepatic Tumors: the Significance of Capsular Retraction

PURPOSE: To evaluate the prevalence of capsular retraction in malignant hepatic tumors and the factorsinvolved. MATERIALS AND METHODS: Between January 1994 and December 1996, we retrospectively reviewed the CT scansof 152 patients with pathologically-proven, peripherally-located, malignant hepatic tumors. We evaluated size,site, portal and hepatic venous obstruction, bile duct dilatation, and liver atrophy in 18 cases involvingcapsular retraction. RESULTS: The overall prevalence of capsular retraction among malignant hepatic tumors was18/152(12%) ; the prevalence was 9/129(7%) in hepatocellular carcinoma, 6/14(43%) in cholangiocarcinoma and3/9(33%) in metastatic cancer ; among cases of cholangiocarcinoma and metastatic cancer, the prevalence washigh(p <0.05). Portal venous obstruction was seen in six patients with hepatocellular carcinoma (a high incidence ;p=0.041) and one with cholangiocarcinoma. Hepatic venous obstruction was demonstrated in one patient withhepatocellular carcinoma and one with cholangiocarcinoma. Among cholangiocarcinoma patients, bile duct obstructionwas seen in four and liver atrophy in three, but among metastatic cancer cases there were no similar findings. CONCLUSION: The main factors causing capsular retraction were portal venous obstruction in hepatocellularcarcinoma and bile duct obstruction and liver atrophy in cholangiocarcinoma.