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Purpose: Malalignment of syndesmosis is generally associated with a poor outcome, yet occurs at a high rate in malleolar ankle fractures. In this study, we examine whether malreduction of syndesmosis injury associated with malleolar ankle fracture can be avoided using Weber's three indexes in the mortise view., Materials and Methods: Of 156 patients with malleolar ankle fracture who underwent surgery from December 2012 to March 2016 at two medical facilities, 24 patients who received syndesmotic screw fixation were included in the study. Fractures were Danis-Weber types B and C in 8 (8/134, 6.0%) and 16 (16/22, 72.7%) patients, respectively. Using axial computed tomography (CT), we calculated the difference between injured and non-injured sides for each of three parameters: tibiofibular clear space (TFCS), anterior tibiofibular interval (ATF), and fibular rotation (θ fib ). Malreduction was diagnosed if one or more of the three parameters had an abnormal value. Weber's three indexes in the mortise view on the injured side were used to determine whether reduction of syndesmosis was performed successfully. Consistency between the evaluation of reduction of syndesmosis in axial CT images and reevaluation of mortise views was examined by calculation of sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV)., Results: The rate of malreduction of syndesmosis in axial CT images was 29.2% (7/24). Re-evaluation in the mortise view confirmed malreduction of syndesmosis in six of the seven subjects, all of whom also had malreduction based on axial CT images. The one subject in whom malreduction could not be detected in a mortise view showed an abnormal value only for ATF. Use of the mortise view for perioperative diagnosis had a sensitivity of 0.857, specificity of 1.000, PPV of 1.000, and NPV of 0.944., Conclusion: The results of our study show that malreduction of syndesmosis can be avoided by careful interpretation of intraoperative perspective mortise views based on Weber's three indexes. To increase the diagnostic accuracy further, it is important to detect anteroposterior deviation of the fibula in intraoperative lateral views., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Purpose: The purpose of this study was to observe long-term osseous healing of the cleavage space between bone fragments after intraoral vertical ramus osteotomy using computed tomographic (CT) values., Patients and Methods: CT examinations were performed to observe long-term osseous healing immediately after intraoral vertical ramus osteotomy and at 6 months, 1 year, and 2 years postoperatively. Bone fragments were observed on the interior and lateral sides. CT values between bone fragments were used to measure the range of each point within a 1.7- × 1.7-mm square, and the mean of the measurements was calculated., Results: CT values between bone fragments increased significantly over time at 1 month, 6 months, 1 year, and 2 years after surgery., Conclusions: Osseous healing in the cleavage between bone fragments after intraoral vertical ramus osteotomy was successful according to CT values., (Copyright © 2013 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.)

Background: Rugby is a collision sport with a high risk of shoulder injury. Although traumatic anterior shoulder instability is common, the long-term effects of rugby and joint instability on the shoulder have not been described; thus, this study assessed the effects of rugby itself, and joint instability, on the glenoid cavity., Materials and Methods: Both sides of the shoulders from 25 rugby players and 17 control patients with unilateral shoulder instability were prospectively evaluated by means of computed tomography osteoabsorptiometry, which represents the distribution of mineralization in subchondral bone plate (DMSB) as a marker of the long-term loading history of a joint. For the quantitative analysis, intergroup differences of maximum Hounsfield unit (HU) values in 7 areas on the glenoid were assessed in the uninjured intact shoulder to characterize the influence of rugby. Side-to-side differences of the HUs in each area were assessed in each participant to characterize the effects of shoulder instability. For the qualitative analysis, associations between the patterns of each DMSB and each group were assessed by means of correspondence analysis., Results: All examined areas on the glenoid had a significantly higher HUs in rugby players. Shoulder instability affected the HUs in both groups. A qualitative analysis demonstrated that the maximum HU tended to be shifted more inferiorly in rugby players and in the unstable shoulders., Conclusions: Rugby affects the shoulder joint, regardless of any history of instability, suggesting that "rugby shoulder" tends to involve degenerative changes, such as osteoarthritis or labral tears., (Copyright © 2013 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Mosby, Inc. All rights reserved.)

Objective: To determine the accuracy of postmortem computed tomography (PMCT) for the assessment of causes in nontraumatic deaths in children., Study Design: We enrolled cases of nontraumatic deaths of infants and children who underwent PMCT at a single center. The presumed cause of death determined by PMCT was prospectively compared with the clinical and pathological diagnoses of deaths., Results: Thirty-eight cases were enrolled for analysis. Among them, seven cases also underwent conventional medical autopsy. PMCT revealed an identifiable cause of death in accordance with the clinical diagnosis of death in 16 cases of the 38 cases (the concordance rate was 42%) and in accordance with the autopsy cause of death in four of the seven autopsy cases (the concordance rate was 57%). Among eight cases with unknown cause of death by clinical diagnosis, four cases (50%) were identified with cardiac tamponade as a cause of death (one case) and intracranial hemorrhage suggesting abuse (3 cases)., Conclusions: PMCT seems to be a promising technique that might serve as a substitute for conventional medical autopsy and give us the complementary information to clinical diagnoses particularly in cases of child abuse. Larger multicenter trials are worthwhile to validate the general feasibility of PMCT.

Peritoneal lymphomatosis (PL) is an extensive lymphomatous infiltration of the intraperitoneal portion of the subperitoneal space, which is a rare presentation of lymphoma. Using CT or MRI findings alone, it is difficult to differentiate between lymphomatosis, carcinomatosis, and other pathological entities.We experienced two PL cases and herein report the FDG-PET/CT findings. High FDG uptakes were found in omental and peritoneal infiltration, gastric wall involvement, and lymph node involvement in the epiphrenic region, although retroperitoneal lymph node involvement was absent. Systemic abnormal FDG uptakes suggested PL rather than carcinomatosis, and FDG-PET/CT findings were useful for the diagnoses.

Objectives: To retrospectively assess the utility of semi-automated measurements by stratification of CT values of tumour size, CT value and doubling time (DT) using thin-section computed tomography (CT) images. The post-surgical outcomes of favourable and problematic tumours (more advanced p stage than IA, post-surgical recurrence or mortality from lung cancer) were compared using the measured values. The computed DTs were compared with manually measured values., Methods: The study subjects comprised 85 patients (aged 33-80 years, 48 women, 37 men), followed-up for more than 5 years postoperatively, with 89 lung lesions, including 17 atypical adenomatous hyperplasias and 72 lung cancers. DTs were determined in 45 lesions., Results: For problematic lesions, whole tumour diameter and density were >18 mm and >-400 HU, respectively. The respective values for the tumour core (with CT values of -350 to 150 HU) were >15 mm and >-70 HU. Analysis of tumour core DTs showed interval tumour progression even if little progress was seen by standard tumour volume DT (TVDT)., Conclusion: Software-based volumetric measurements by stratification of CT values provide valuable information on tumour core and help estimate tumour aggressiveness and interval tumour progression better than standard manually measured 2D-VDTs.

Purpose: We evaluated the relationship between internal thoracic artery (ITA) stenosis anastomosed to the left anterior descending artery (LAD) and the degree of LAD stenosis using 320-detector row computed tomography (320-ADCT) and adenosine thallium-201 myocardial perfusion scintigraphy (Tl-201-MPS)., Methods: We included 101 patients who underwent coronary artery bypass grafting (CABG) using ITA grafts; 320-ADCT and adenosine Tl-201-MPS were performed 2-3 months after CABG. Clinical parameters, degree of LAD stenosis, and regional myocardial ischemia of the LAD territory were compared between patients without ITA stenosis (Group A) and with ITA stenosis (Group B)., Results: Thirty patients (30%) had ≤75% LAD stenosis, and 9 patients (30%) showed significant ITA stenosis. Regional ischemia was noted in 23 patients (23%). There were no differences in clinical parameters between the 2 groups. Twenty-two patients (24%) in Group A and 8 patients (89%) in Group B had ≤75% LAD stenosis (P <0.002). No Group B patients had regional myocardial ischemia of the LAD territory., Conclusion: We concluded that ≤75% LAD stenosis significantly influences ITA stenosis, without associated regional myocardial ischemia of the LAD territory. Non-invasive 320-ADCT and adenosine Tl-201-MPS for ITA evaluation may be useful for long-term follow-up of patients after CABG.

Oxide-nitride-oxide (ONO) layer structures are widely used for charge storage in flash memory devices. The ONO layer interfaces should be as flat as possible, so measurement of the nanoscale roughness of those interfaces is needed. In this study, quantification of an ONO film from a commercially available flash memory device was carried out with a pillar-shaped specimen using scanning transmission electron microscopy (STEM) and computed tomography. The ONO area contained only low Z- and low STEM-contrast materials, which makes high-quality reconstruction difficult. The optimum three-dimensional reconstruction was achieved with an STEM annular dark-field detector inner collection angle of 32 mrad, a sample tilt range from -78° to +78° and 25 iterations for the simultaneous iterative reconstruction technique.

Objective: We evaluated the partial volume effect in PET/CT images and developed a simple correction method to address this problem., Methods: Six spheres and the background in the phantom were filled with F-18 and we thus obtained 4 different sphere-to-background (SB) ratios. Thirty-nine cervical lymph nodes in 7 patients with papillary thyroid carcinoma (15 malignant and 24 benign) were also examined as a preliminary clinical study. First, we developed recovery coefficient (RC) curves normalized to the maximum counts of the 37-mm sphere. Next, we developed a correction table to determine the true SB ratio using three parameters, including the maximum counts of both the sphere and background and the lesion diameter, by modifying the approximation formula of the RC curves including the point-spread function correction. The full width at half maximum in this formula is estimated with the function of the SB ratio., Results: In the phantom study, a size-dependent underestimation of the radioactivity was observed. The degree of decline of RC was influenced by the SB ratio. In preliminary clinical examination, the difference in the SUV(max) between malignant and benign LNs thus became more prominent after the correction. The PV correction slightly improved the diagnostic accuracy from 95 to 100%., Conclusions: We developed a simple table lookup correction method for the partial volume effect of PET/CT. This new method is considered to be clinically useful for the diagnosis of cervical LN metastasis. Further examination with a greater number of subjects is required to corroborate its clinical usefulness.

Objective: The aims of this retrospective study were to evaluate the incidence of residual lymph node (LN) metastases in high-risk papillary thyroid cancer (PTC) patients receiving adjuvant I-131 therapy, especially in those without I-131 accumulation, and to evaluate the clinical usefulness of F-18 FDG PET/CT to detect those lesions., Methods: The 37 PTC patients receiving adjuvant I-131 therapy were retrospectively evaluated. We examined the incidence of residual LN metastasis and compared the accumulation of F-18 FDG and I-131 in those lesions, and compared the serum thyroglobulin (Tg) levels between patients with and without residual LN metastases., Result: A total of 33 lesions were diagnosed as residual LN metastases in 9 patients. FDG accumulated in all of the lesions, but 19 lesions (57.6%) of them had no I-131 accumulation. The SUVmax was significantly higher in lesions without I-131 accumulation than in lesions with I-131 accumulation (6.6 +/- 2.8 vs. 4.2 +/- 1.8; P = 0.007). The serum Tg levels were significantly higher in patients with residual LN metastases than in patients without it (709.9 +/- 1470.8 vs. 25.6 +/- 37.1 ng/mL; P = 0.005). The incidence of residual LN metastasis was significantly higher in patients with a detectable serum Tg level than in patients without it (35.0% vs. 0%, P = 0.03)., Conclusion: These results indicate that the residual LN metastasis was relatively common in high-risk PTC patients receiving adjuvant I-131 therapy whose serum Tg levels remained detectable, and those lesions often had no I-131 accumulation. FDG-PET/CT would be recommended for PTC patients with detectable serum Tg levels to detect residual LN metastases.

Objective: The goal of this study was to investigate the utility of multidetector-row computed tomography (MDCT) and adenosine triphosphate stress cardiac single photon emission computed tomography (ATP-SPECT) in evaluating coronary artery disease (CAD) in patients scheduled for non-cardiac surgery., Patients and Methods: We routinely performed echocardiography and exercise stress electrocardiography as preoperative cardiac screening examinations for patients scheduled for non-cardiac surgery under general anesthesia. Of 848 consecutive preoperative patients (Non-invasive Group), 49 patients with abnormalities of these screening examinations had MDCT and ATP-SPECT. Of 809 consecutive preoperative patients studied at an earlier time (Invasive Group), 58 patients with abnormalities of these screening examinations had cardiac catheterization as an additional cardiac examination., Results: The number of patients in the non-invasive and invasive subgroups having additional screening examinations was comparable, and there was no significant difference in perioperative cardiac events between the two subgroups. Based on results of the additional tests in the two subgroups, preoperative prophylactic invasive treatment for CAD was carried out in a small number of patients, again with no significant differences between the groups. However, total medical expenses for the additional cardiac examinations were significantly reduced in the non-invasive subgroup compared with the invasive subgroup (140,030+/-34,800 vs. 187,170+/-26,120 yen, respectively, p=0.0002)., Conclusion: Non-invasive examination prior to noncardiac surgery using MDCT and ATP-SPECT in a subgroup of patients suspected of having CAD appears to be a useful screening procedure. Compared with invasive cardiac catheterization, CT testing has comparable diagnostic utility without an increase in perioperative cardiac events, and in addition, it has an improved cost-benefit profile.

Study Design: A multicenter cohort study was performed retrospectively., Objective: To identify radiographic predictors for the development of myelopathy in patients with ossification of the posterior longitudinal ligaments (OPLL)., Summary of Background Data: The pathomechanism of myelopathy in the OPLL remains unknown. Some patients with large OPLL have not exhibited myelopathy for a long periods of time. Predicting the course of future neurologic deterioration in asyptomatic patients with OPLL is difficult at their initial visit., Methods: A total of 156 OPLL patients from 16 spine institutes with an average of 10.3 years of follow-up were reviewed. Subjects underwent a plain roentgenogram, computed tomography (CT), and magnetic resonance imaging of the cervical spine during the follow-up. The trauma history of the cervical spine, maximum percentage of spinal canal stenosis in a plain roentgenogram and CT, range of motion of the cervical spine, and axial ossified pattern in magnetic resonance imaging or CT were reviewed in relation to the existence of myelopathy., Results: All 39 patients with greater than 60% spinal canal stenosis on the plain roentgenogram exhibited myelopathy. Of 117 patients with less than 60% spinal canal stenosis, 57 (49%) patients exhibited myelopathy. The range of motion of the cervical spine was significantly larger in patients with myelopathy than in those of without it. The axial ossified pattern could be classified into 2 types: a central type and a lateral deviated type. The incidence of myelopathy in patients with less than 60% spinal canal stenosis was significantly higher in the lateral deviated-type group than in the central-type group. Fifteen patients of 156 subjects developed trauma-induced myelopathy. Of the 15 patients, 13 had mixed-type OPLL and 2 had segmental-type OPLL., Conclusion: Static and dynamic factors were related to the development of myelopathy in OPLL.

Background/purpose: The cause of extrahepatic portal hypertension in children has not been clarified. Our aim was to determine the morphological features of the extrahepatic portal vein in children with extrahepatic portal hypertension by 3-dimensional computed tomographic portography and to clarify the etiology of this disorder., Materials and Methods: Six patients ranging in age from 10 to 18 years (median age, 12.8 years) who had portal hypertension presented with hematemesis. They underwent intravenous computed tomographic portography using a helical computed tomography scanner and 3-dimensional image reconstruction., Results: The extrahepatic portal vein was visualized in all patients by 3-dimensional computed tomographic portography. None of the patients showed extrahepatic portal vein obstruction or cavernous transformation. All patients had a tortuous eta-shaped extrahepatic portal vein, and a line could be drawn through the flexures of the portal vein to the hepatic hilum., Conclusion: In children, extrahepatic portal hypertension is not caused by extrahepatic portal vein obstruction and may be of embryological origin.

The presentation of the surgical anatomy of anorectal malformation by standard anatomical figures is not suitable for individual anorectoplasty. It is essential to understand the anatomy of the pelvic muscle (striated muscle complex: SMC) including the external anal sphincter and their three-dimensional (3D) configuration in each patient. Thus, we studied the SMC three-dimensionally with multidetector-row helical computed tomography (MRH-CT) preoperatively, and evaluated its usefulness. Fourteen patients with anorectal malformations before anorectoplasty (types: high n=6, intermediate n=2, low n=6) and two patients without anorectal malformations as controls (total: male n=8, female n=8) were investigated. An image of pelvic region was prepared with a slice thickness of 0.5 mm and a reconstruction pitch of 0.5 mm. A 3D reconstruction on a conventional personal computer (PC) was made with a volume rendering method, and assisted by our own software. The SMC was analyzed with three modified modes of 3D reconstruction corresponding to the surrounding tissues. A length of the parasagittal muscle, and both the sagittal and transverse width of the vertical fibers in the SMC at the connection to the parasagittal muscle were measured on a 3D image and then compared among three different types and controls. To eliminate variations in age, a length index was used to allow comparison. The 3D configuration of the SMC was different in every case. The arranged image mode, which displayed the SMC and the pelvic bones simultaneously, enabled to use conventional knowledge in cysto-urethrography. The length of the parasagittal muscle was longest in the high type but the width of the vertical fibers was smallest. Anatomical figures of the SMC including the external anal sphincter were clearly demonstrated on a PC in every anorectal malformation by our program. A 3D reconstruction image provides positional information on the SMC for the body surface and pelvic bone at the same time. Both a 3D image and positional information with MRH-CT offers the surgeon a simulated operative profile of the SMC superior to CT or magnetic resonance imaging slices alone.

Background and Purpose: Our purpose was to evaluate the visualization of the artery of Adamkiewicz (AKA) and the anterior spinal artery (ASA) by using multi-detector row CT. Preoperative detection of the AKA and ASA is important for prevention of ischemic complications of thoracoabdominal aortic surgery., Methods: Data from contrast-enhanced CT of the abdomen of 19 consecutive patients with known or suspected liver disease were evaluated. The scanning range was set from the level of the diaphragm to the lower edge of the liver. After bolus injection of contrast material (100 mL of iohexol, 350 mgI/mL, 5 mL/s), arterial phase scans were obtained by using a four-channel multi-detector row CT scanner. The scanning parameters included a detector row configuration of 4 x 2 mm, a pitch of 5:1, a gantry rotation speed of 0.5 s, 120 kVp, and 150 mAs. Arterial phase coronal multiplanar reconstruction scans obtained parallel to the spinal cord were evaluated by two neuroradiologists. The detectability of ASA and AKA was analyzed., Results: The AKA was visualized on the scans of 13 of 19 patients (68%). The segmental level of AKA origin ranged from T10 to L2. The AKA originated from the left side in nine patients (69%) and the right side in four patients (31%). The ASA was visualized on the scans of all patients (100%). For 16 of the 19 patients, the ASA was detected in its full length from the cranial edge of the scan range. However, the ascending branch of the ASA distal to the junction of the AKA was not detected for the remaining three patients., Conclusion: The AKA and ASA can be visualized by using multi-detector row CT with the use of IV administered contrast material. Multi-detector row CT could be a useful tool in the evaluation of spinal vascular structures.

We report here two fully documented cases of hamatometacarpal fracture-dislocation following trauma and treated in our hospital. In our cases, the patients suffered hamate fracture in association with metacarpal dislocation. In the first case, a dorsal oblique fracture of the hamate was associated with a dorsal dislocation of the base of the fourth metacarpal. In the second case, a dorsal oblique fracture of the hamate was not associated with a dorsal dislocation of the base of the fifth metacarpal. This diagnosis should be suspected on initial review of plain radiographs, which must include an oblique view because of diagnostic difficulty for this injury. We recommend three dimensional computed tomography (3D-CT) in any patient presenting with pain after blunt trauma to the hand to prevent in diagnosis. Open reduction and internal fixation of the fracture is indicated and relevant for displaced fracture.

We report a 15-year-old girl with nutcracker syndrome (NCP) in whom three-dimensional helical computed tomography (3D helical CT) was useful for diagnosis; angiographic imaging using 3D helical CT provided fine outlines of the vascular structures in NCP, i.e., a compression of the left renal vein between the aorta and the superior mesenteric artery and the abnormal acute angle between them. Thus, a 3D helical CT enables precise depiction of the anatomical characteristics of renal vasculature and, therefore, may be a useful alternative imaging technique instead of conventional examinations, such as invasive venography or digital subtraction angiography. Further study in a large number of children with vascular abnormalities would be worthwhile.

We performed thoracoscopic biopsies of small pulmonary nodules in 13 patients by placing hookwires adjacent to the target nodules under computed tomographic (CT) guidance. Biopsies were successfully performed in 10 of the 13 patients. Placement of individual hookwires for this purpose took from 20 to 50 minutes (30 minutes on average). Excisional biopsies of individual nodules required 20 to 60 minutes (37 minutes on average). Although pneumothorax developed in one patient, treatment was not considered necessary. This biopsy technique was unsuccessful in 3 cases, in 2 of which the hookwire became dislodged, and in 1 of which the target nodule was not contained in the resected specimen. These experiences seemed to underscore the importance of placing CT-guided hookwires more deeply into lung tissue near the target nodules. The technique appears to be useful for thoracoscopic biopsies of peripheral pulmonary nodules that otherwise would be difficult to identify by endoscopic probing forceps.

Objective: The purpose of this study was to use helical CT to elucidate the anatomy and clinical importance of cholecystic venous drainage., Subjects and Methods: We performed helical CT of the upper abdomen during injection of contrast medium through a superselectively catheterized cholecystic artery (cholecystic artery CT) in 28 patients, all of whom were surgical candidates for suspected hepatobiliary abnormality. In nine of these patients, CT during arterial portography (CTAP) was also performed., Results: Cholecystic venous blood most frequently entered peripheral portal branches of hepatic segment V (27 of 28 patients, 96%) and segment IV (26 of 28, 93%). In order of decreasing frequency, cholecystic venous blood also drained to segments I, VI, VIII, III, and VII. Cholecystic venous blood subsequently drained into the middle hepatic vein (21 of 28, 75%) or right hepatic vein (20 of 28, 71%). In two patients with adenocarcinoma involving the gallbladder associated with multiple liver metastases, cholecystic venous drainage was seen around each metastatic focus. In the nine patients in whom both cholecystic artery CT and CTAP were performed, nontumorous portal perfusion defects were attributable to cholecystic venous drainage., Conclusion: Recognition of cholecystic venous drainage as a possible pathway for spread of disease from the gallbladder to the liver and also as one of the causes of non-tumorous portal perfusion defects seen on CTAP is important.

Background: To compare the value of helical computed tomography (CT) and various pulse sequences of magnetic resonance (MR) imaging in the detection and staging of small pancreatic adenocarcinoma., Methods: Small pancreatic adenocarcinomas (< or = 2 cm in diameter) in eight patients were evaluated with both helical CT and MR imaging. Five MR imaging pulse sequences that included fat-suppressed T1-weighted images and dynamic study using fast multiplanar spoiled gradient-recalled technique were compared for the tumor detectability. To evaluate the tumor vascularity, angiographic findings were also investigated., Results: Helical CT delineated the tumor in five cases, and MR imaging depicted the tumor in seven cases. MR imaging could detect the tumor of 0.8 cm in diameter clearly. Although helical CT and dynamic MR imaging missed the tumor of 2 cm with relative hypervascularity, fat-suppressed T1-weighted MR imaging demonstrated it precisely. As for the tumor staging, MR imaging was equal or slightly superior to helical CT., Conclusion: MR imaging is the first modality of choice to evaluate small pancreatic adenocarcinoma, and fat-suppressed T1-weighted images and dynamic study must be performed.

Background: Although helical computed tomography (HCT) has been widely employed for the evaluation of pancreatic tumors, its capability in the diagnosis of peripancreatic arterial invasion has not been established., Methods: HCT with a sequential cine-display was carried out in 34 patients with solid pancreatic tumors and 28 control subjects without angiographic abnormality. The HCT scans were compared with angiograms., Results: All major arteries (celiac, superior mesenteric, splenic, gastroduodenal) and superoanterior pancreaticoduodenal arteries were well demonstrated by HCT in control subjects. However, posterior pancreaticoduodenal arcades and other smaller arteries were poorly identified. Although 19 major arterial invasions were equally diagnosed by HCT and angiography in patients with pancreatic tumors, only 4 of 11 minor arterial invasions were correctly diagnosed by HCT., Conclusions: Although HCT has some limitations in the evaluation of minor peripancreatic arteries, it can provide enough information for making a decision about conducting pancreatic surgery.

Purpose: The purpose of this study was to evaluate the performance of helical CT in preoperative T-staging in patients with gastric cancer., Method: A total of 71 patients with an established diagnosis of gastric cancer [75 lesions, 46 early (T1) and 29 advanced (T2 or more) cancers] were evaluated with helical CT. Helical CT was performed with 5-mm slice thickness at 5-mm/s table incrementation. Using the volumetric data by helical scanning, axial CT images (5-mm slice thickness at 5-mm intervals) and multiplanar reconstruction (MPR) images were obtained. CT findings were compared with histopathologic studies of the resected specimen., Results: Sensitivity of helical CT for gastric cancer was 26% (12 of 46) for early and 100% (29 of 29) for advanced cancer. Three lesions were misdiagnosed as gastric cancer by helical CT. Histopathologically, all early gastric cancers detected by helical CT were either polypoid or elevated types or showed massive invasion of the submucosal layer. The differentiation between T1 cancer with massive submucosal invasion and advanced cancer was difficult. The differentiation between T2 and T3 cancer was possible in 73% (19 of 26) and between T1/T2 and T3/T4 (extraserosal invasion) in 83% (34 of 41). Overall T-staging was correct in 66% (27 of 41). MPR images improved the detection rate (three lesions) or increased confidence in T-staging (eight lesions) over axial CT images., Conclusion: When helical CT detected gastric cancer that was not a polypoid or elevated type with underlying normal-appearing gastric wall, it was either T1 cancer with massive invasion of the cancer cells into the submucosal layer or advanced cancer. However, differentiation between these two stages was difficult on CT. Diagnosis of serosal invasion was not markedly improved by helical CT. MPR images increased confidence in the staging of certain gastric cancers, such as those in locations where CT images are susceptible to partial volume averaging effects.

Objective: To analyze CT findings of Bellini duct carcinoma, a rare variant of renal cell carcinoma., Materials and Methods: The CT findings of five cases of Bellini duct carcinoma were reviewed and the findings were recorded., Results: In all cases the affected kidneys maintained the normal outer contours. In four cases the renal masses protruded into the central sinuses. Contrast enhancement was minimal in four cases., Conclusion: Bellini duct carcinoma should be suspected in cases with these CT findings.

Objective: Our goal was to elucidate the CT and MRI findings of inflammatory pseudotumors of the spleen., Methods: The CT and MRI findings of three patients with inflammatory pseudotumors of the spleen were reviewed and compared with the pathologic findings., Results: On the early phase of CT, the masses were hypodense to the normal spleen, and on the delayed phase, they demonstrated delayed enhancement. On T1-weighted MR images, the masses were isointense to the normal spleen, and on T2-weighted images, the masses had heterogeneous low signal intensities. After administration of Gd-DTPA, the masses showed delayed enhancement., Conclusion: Inflammatory pseudotumors of the spleen were characterized by low signal intensity on T2-weighted MR images and delayed enhancement after contrast material administration on CT and MRI. The fibrous stroma may contribute to these unusual findings.

Background: Because of its poor prognosis, the diagnosis of hepatocellular carcinoma with sarcomatous change (HCCSC) is clinically important. The purpose of this study is to elucidate the characteristic CT findings of HCCSC., Methods: Two-phased dynamic incremental CT images of six histologically proven HCCSC were retrospectively reviewed., Results: All tumors (100%) exhibited peripheral enhancement on delayed CT images. Lymphadenopathy was observed in 100% (six of six patients); intrahepatic metastases, in 83% (five of six). Both metastatic lesions showed findings similar to those of the primary hepatic tumors, such as peripheral enhancement. Histopathological delayed and/or prolonged peripherally enhanced areas consisted of viable cancer cells with sarcomatous changes., Conclusions: The appearance of HCCSC on CT is that of an irregularly demarcated intrahepatic mass with delayed or prolonged peripheral enhancement, frequently with intrahepatic metastases and lymphadenopathy.

Purpose: To determine the efficacy of helical computed tomography (CT) in the detection of lymphadenopathy in patients with gastric cancer., Materials and Methods: Helical CT (5-mm section thickness, 5-mm/sec table incrementation) was performed in 58 patients (39 men, 19 women; mean age, 63.8 years) with gastric cancer; 1,082 lymph nodes (138 positive, 944 negative for metastasis) were resected at surgery. Findings at CT and resection were compared. Sensitivity for detecting lymph nodes was evaluated according to nodal size and presence of metastasis., Results: Seven (1.1%) of 649 lymph nodes 1-4 mm, 160 (45.1%) of 355 nodes 5-9 mm, and 56 (72%) of 78 nodes larger than 9 mm were detected at CT. For nodes of at least 5 mm, sensitivity for detecting metastasis-positive nodes (79 [75.2%] of 105 nodes) was higher than that for detecting metastasis-negative nodes (137 [41.8%] of 328; P < .01). Differences between positive and negative nodes in CT attenuation (110 HU +/- 25 vs 66 HU +/- 32) and short-to-long axis ratios (0.81 +/- 0.15 vs 0.57 +/- 0.15; P < .001) were significant., Conclusion: Helical CT is effective for detection of metastatic lymphadenopathy from gastric cancer. CT attenuation and lymph-node configuration aid in diagnosis of malignant adenopathy.

Rationale and Objectives: To elucidate the characteristic clinicopathologic features of hepatocellular carcinomas (HCCs) undetected on two-phased incremental computed tomography (CT)., Methods: Computed tomographic scans of 115 surgically resected small (< or = 3 cm) HCCs from 83 patients were performed 45 seconds and 6 minutes after the administration of contrast material. These scans were compared with corresponding angiographic and histopathologic findings., Results: Eighty HCCs (70%) were depicted on the early images; 73 (63%) on the delayed images; and 89 (77%) using two-phased incremental CT. The small HCCs undetected on the early images but seen histologically had the following characteristics: (1) absence of a fibrous capsule, (2) well-differentiated tumor, (3) replacing growth patterns of the tumors, (4) lack of fatty metamorphosis and/or clear cell changes, (5) hypovascular on angiography. Those not seen on delayed images had the following characteristics: (1) absence of a fibrous capsule, (2) replacing growth patterns, and (3) presence of portal tracts in the tumors., Conclusions: The replacing growth pattern and the presence of portal tracts correlate with the undetectability on CT. For HCCs undetected on CT, treatment methods must be considered carefully, because the HCCs may be receiving transsinusoidal and portal blood supplies.

We retrospectively studied the CT findings of renal tuberculosis in 27 cases (32 kidneys). As a characteristic CT finding, nodular lesions were recognized in 20 kidneys. Low density nodules were found in three kidneys, isodensity nodules in seven, and high density nodules in 10. In a case examined by follow-up five years later, the low and isodensity nodules changed to high density nodules with decreasing volume. Ultrasound demonstrated the high density nodules as low-echo mass lesions. These nodular lesions corresponded with the localized foci in the renal parencyma and/or pyocalyx. We consider that the density differences in nodular lesions reflect the process of water absorption from the caseous necrotizing materials of tuberculosis.

In order to grade pathologic factors that influence CT findings in hepatocellular carcinomas (HCCs), the CT-pathologic correlation was assessed statistically using univariate and multivariate analyses of 75 lesions. CT findings of early and delayed phase scans using two-phase dynamic incremental CT (TDICT) were compared with pathologic findings in resected specimens to calculate a category score for each pathologic finding. According to category scores, histopathologic differentiation and growth pattern were the major determinants of tumor density. Determinants of the internal structure of tumors were cytological variants, histologic differentiation, and macroscopic classification, in that order. Macroscopic classification, histologic differentiation, fibrous capsule characteristics, and growth pattern were important in descending order for tumor margins. Histologic differentiation was the most important factor for determining TDICT findings in HCCs. The CT findings were modified by parenchymal liver disease and cytologic variants.

Two-phase dynamic incremental CT is a technique in which CT scans are obtained 45 sec and 6 min after commencing the rapid bolus injection of contrast medium. We analyzed the contrast enhancement patterns of three types of hepatic tumors (72 hepatomas, 39 hemangiomas, and 28 metastases) in 139 patients to determine if any differences in the patterns are useful in the differential diagnosis of these lesions. Dynamic incremental CT scanning was performed after 100 ml of iodinated contrast material was administered i.v. with a power injector at a rate of 2 ml/sec. A 1-sec scanning time was used with a 1.6-sec inter-scan delay, which allowed table motion between scans. CT scans (eight to 16 sections) were obtained 45-110 sec (early phase) and 6-7 min (delayed phase) after commencing the injection of contrast medium. The enhancement patterns of hepatomas were as follows: 32% were totally hyperdense in the early phase and totally hypodense in the delayed phase, while 24% were totally hypodense in both phases. Most of the hepatomas (88%) appeared as totally hypodense lesions in the delayed phase. In the case of hemangiomas, 56% were peripherally hyperdense in the early phase; in the delayed phase, 36% were isodense and 31% were totally hyperdense. Most hemangiomas (85%) were not totally hypodense in the early phase, and no hemangioma was totally hypodense in both phases. In the early phase, 61% of metastases were hypodense. In the delayed phase, 57% were hypodense. Metastases most commonly were totally hypodense in both phases (43%). We conclude that contrast enhancement patterns of hepatomas, hemangiomas, and metastases seen on two-phase dynamic incremental CT scans are useful in the differential diagnosis of these tumors.

Williams-Campbell syndrome is a rare type of cystic bronchiectasis that is due to defective cartilage of fourth-to sixth-order bronchi. The diagnosis has been made either at autopsy or by bronchographic findings. The article describes an adult case of this syndrome with CT findings that are characteristic of this entity. CT showed areas of emphysematous lung parenchyma distal to the dilated bronchi, suggesting bronchiolitis obliterans secondary to proximal cystic bronchiectasis. These findings are useful in differentiating Williams-Campbell syndrome from other causes of cystic bronchiectasis, thus obviating bronchography.

A case of idiopathic interstitial pneumonia (IIP) with pneumothorax and pneumomediastinum was presented. A 52-year-old male was admitted with the complaint of cough, fever and dyspnea. Chest roentgenogram revealed bilateral reticulonodular shadow and right pneumothorax. Radiological, laboratory and clinical findings were consistent with the diagnosis of acute exacerbation of IIP. Repeated chest CTs showed diffuse interstitial opacities and the presence of pneumothorax and pneumomediastinum. Furthermore, honeycombing and bullous change progressed markedly for two months. The mechanisms of pneumothorax and pneumomediastinum were speculated to be due to the rupture of those cystic lesions which had grown rapidly on follow-up CTs. It was suggested that the formation of honeycombing occurred within a few months and the increasing of honeycombing might be accompanied by so-called acute exacerbation of IIP. We propose that follow-up CTs were useful for the chronological study for interstitial lesions of IIP.

CT findings in ninety-nine patients with trigeminal neuralgia were reviewed. Brain tumors including three trigeminal neurinomas, three meningiomas, one epidermoid, one acoustic neurinoma, were found in eight cases as a cause of symptomatic trigeminal neuralgia. Among seventy-nine patients with idiopathic trigeminal neuralgia, four cases had vascular decompression surgery because of the tortuous, ectatic or anomalous vertebrobasilar artery. Among the other seventy-five non-surgical cases, seventeen cases showed the tortuous and/or ectatic vertebrobasilar artery on CT, and this group of patients showed slightly higher recurrence rate of trigeminal neuralgia after nerve block or medication compared with other non-surgical patients. CT is thought to be a useful screening imaging modality for evaluation of patients with trigeminal neuralgia, and angiography is required for precise evaluation of the compressing vessels when surgical treatment is contemplated.

We reviewed the computed tomographic (CT) findings of postoperative maxillary cyst (POMC) in 64 patients with 79 lesions, and evaluated its diagnostic efficacy. Typical CT finding of POMC was an expansile and homogeneous soft tissue mass with bone erosion. Thin-walled capsule and bony septation were also demonstrated in 72% and 35% of the lesions, respectively. A comparison between conventional tomography and CT has been made in the same subjects for evaluation of the detectability and extension diagnosis of POMC. CT proved to be superior to conventional tomography in diagnosing the presence and the extent of POMC. We conclude that conventional tomography is not necessary in diagnosis of POMC, when full examination of the paranasal sinus is performed by CT.

One hundred thirty-four patients with histo-pathologically proven bronchogenic carcinoma underwent computed tomography (CT) of the thorax and adrenal glands. Prospectively, 23 of the 134 patients had adrenal metastasis, based on CT criteria for enlargement of the gland. Retrospectively, however, some proved to be false positives. In addition, the diagnosis of adrenal metastasis frequently altered the initial staging and the treatment modality. We suggest that valid diagnoses of adrenal metastases on CT scan be made on the basis of altered shape as well as on altered size of the gland.