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Background: Obstructive sleep apnea syndrome (OSAS) is associated with augmented sympathetic nerve activity and cardiovascular diseases. However, the interaction between coronary artery plaque characteristics and sympathetic nerve activity remains unclear. The purpose of this study was to clarify the relationships between coronary artery plaque characteristics, sleep parameters and single- and multi-unit muscle sympathetic nerve activity (MSNA) in OSAS patients., Methods and results: A total of 32 OSAS patients who underwent full-polysomnography participated in this study. The coronary plaque volume was calculated with 320-slice coronary computed tomography (CT). Single- and multi-unit MSNA were obtained during the daytime within 1 week from full-polysomnography. Patients were divided into 2 groups according to their apnea-hypopnea index (AHI) score (mild-moderate group, AHI <30; and severe group, AHI ≥30). There were no group differences in risk factors for atherosclerosis; however, severe AHI patients showed significantly high single-unit MSNA, and low- and intermediate-attenuation plaque volumes. In regression analysis, the plaque volume of any CT value was not associated with single- or multi-unit MSNA; only AHI significantly correlated with low-attenuation plaque volume (R=0.52, P<0.05)., Conclusions: Our findings provided the evidence that AHI is an independent predictor for low-attenuated, vulnerable plaque volume, but not daytime MSNA, in patients with OSAS.

Background: We evaluated whether X-map, a novel imaging technique, can visualize ischemic lesions within 20 hours after the onset in patients with acute ischemic stroke, using noncontrast dual-energy computed tomography (DECT)., Materials and Methods: Six patients with acute ischemic stroke were included in this study. Noncontrast head DECT scans were acquired with 2 X-ray tubes operated at 80 kV and Sn150 kV between 32 minutes and 20 hours after the onset. Using these DECT scans, the X-map was reconstructed based on 3-material decomposition and compared with a simulated standard (120 kV) computed tomography (CT) and diffusion-weighted imaging (DWI)., Results: The X-map showed more sensitivity to identify the lesions as an area of lower attenuation value than a simulated standard CT in all 6 patients. The lesions on the X-map correlated well with those on DWI. In 3 of 6 patients, the X-map detected a transient decrease in the attenuation value in the peri-infarct area within 1 day after the onset., Conclusions: The X-map is a powerful tool to supplement a simulated standard CT and characterize acute ischemic lesions. However, the X-map cannot replace a simulated standard CT to diagnose acute cerebral infarction., (Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.)

Rationale and Objectives: To evaluate the clinical utility of three-dimensional (3D) computed tomography (CT) for predicting pleural invasion by peripheral lung cancer., Materials and Methods: CT findings (tumor size, vertical diameter, length and area of the interface between tumor and the pleura, ratios of length and area [Rarea] of interface between tumor and the pleura to tumor size, angle between the tumor and adjacent pleura, presence or absence of pleural thickening, and originally developed 3D pleural patterns) in 201 consecutive patients with lung cancer of ≤3 cm in contact with pleural surface were correlated with pathologic findings. Logistic modeling was used for determining the significant factors for prediction of pleural invasion, and receiver operating characteristic (ROC) curves were used for investigating diagnostic capability of significant factors, resulting in a recommendation to the optimal criteria for predicting pleural invasion and to the optimal threshold for differentiating parietal from visceral invasion., Results: Sixty-one (30%) of the 201 patients had pathologically verified pleural invasion. Logistic modeling revealed that the 3D pleural pattern was the only significant factor (P < .001; relative risk of 7.34). Among every combination of the 3D patterns, skirt-like pattern showed the highest accuracy of 77% for predicting pleural invasion. In differentiating parietal from visceral pleural invasion, ROC analysis revealed that Rarea was optimal for differentiating parietal from visceral pleural invasion, and the highest accuracy of 77% was obtained with a cut-off value of 13.4 for this criterion., Conclusions: Computer-aided 3D CT analysis of the pleura was useful for predicting pleural invasion., (Copyright © 2015 AUR. Published by Elsevier Inc. All rights reserved.)

Objective: The purpose of our study was to develop a simple noninvasive technique for nodal staging using routine preoperative computed tomography (CT)., Materials and Methods: The institutional review board approved this retrospective study, and written informed consent to perform the initial and follow-up CT studies was obtained from all patients. Preoperative CT findings (n=218 patients with resectable non-small cell lung cancer) and pathological diagnoses after surgical resection were evaluated. Using CT images, lymph node section area, circumference, and lesion attenuation values (LAVs) were drawn freehand, and the short axis (SA) and long axis (LA) were measured using caliper software. Receiver operating characteristic (ROC) curves were then used to analyze the section area, circumference, and LAVs., Results: Based on ROC curves, two cut-off values, lymph node section area >30 mm(2) and circumference >25 mm, showed greater sensitivity for nodal staging than the conventional criterion of lymph node SA ≥10 mm or the LA, SA/LA ratio or LAVs. Using lymph node section area >30 mm(2) for diagnosis, the sensitivity, specificity, and accuracy of nodal staging were 90.5%, 56.3%, and 58.3%, respectively. Using lymph node circumference >25 mm, the values were 76.2%, 70.4%, and 70.8%, respectively., Conclusion: Lymph node section area >30 mm(2) and circumference >25 mm can serve as supportive criteria used by radiologists and surgeons to determine nodal staging. If these CT criteria are met, use of a more sensitive procedure such as positron emission tomography or mediastinoscopy is recommended., Concise Abstract: CT is used routinely during preoperative management of lung cancer. Based on ROC analyses, the cut-off values for surface area, circumference, the SA/LA ratio, and LAVs for diagnosis of lymph node metastasis were 30 mm(2), 25 mm, 0.65, and 50 Hounsfield units, respectively. Our findings indicate that lymph node surface area >30 mm(2) and circumference >25 mm are supportive criteria that can be used by radiologists and thoracic surgeons to determine nodal staging and surgical indications., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Surgical resection is the accepted standard of care for patients with non-small cell lung cancer (NSCLC). Several imaging modalities play central roles in the detection and staging of the disease. The aim of this review is to evaluate the utility of computed tomography (CT), magnetic resonance imaging (MRI), positron emission tomography (PET) and PET/CT for NSCLC staging. Radiographic staging refers to the use of CT as a non-invasive diagnostic technique. However, while the vast majority of patients undergo only CT, CT is a notoriously inaccurate means of tumor and nodal staging in many situations. PET/CT clearly improves the staging, particularly nodal staging, compared to CT or PET alone. In addition, as a result of the increased soft-tissue contrast, MRI is superior to CT for distinguishing between tissue characteristics. Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA), which is a minimally invasive technique, also has pathological diagnostic potential. Extensive research and the resultant improvements in the understanding of genetics, histology, molecular biology and oncology are transforming our understanding of lung cancer, and it is clear that imaging modalities such as CT, MRI, PET and PET/CT will have an important role in its preoperative management. However, thoracic surgeons should also be aware of the limitations of these techniques.

Background: Many studies have reported that transverse computed tomography (CT) imaging findings correlate with prognosis of patients with small peripheral lung neoplasm with lepidic growth. However, no studies have examined this correlation with the aid of three-dimensional (3D) CT data., Purpose: To determine the most efficacious imaging factor for differentiation of lepidic growth type lung neoplasms with good prognosis from those with poor prognosis., Material and Methods: We evaluated CT findings, nodule patterns, SUVmax on FDG-PET/CT, as well as nodule volume and ratios of solid parts to nodule volume that were semi-automatically measured on CT images of 64 pulmonary nodules of ≤ 2 cm in 60 consecutive patients (24 men and 36 women; mean age, 65 years). For logistic modeling, we used all of the significant factors observed between the neoplasms with good and with poor prognosis as independent variables to estimate the statistically significant factors for discriminating invasive adenocarcinomas with lepidic growth (lesions with poor prognosis, n=42) from the other neoplasms, including preinvasive lesions (lesions with good prognosis, n=22), resulting in a recommendation for the optimal criterion for predicting lesions with poor prognosis., Results: The logistic regression model identified the ratio of the solid part to the whole volume of a pulmonary nodule as the only significant factor (P=0.04) for differentiating lepidic growth type lung neoplasms with good prognosis from those with poor prognosis. A ratio of 0.238 or more showed the highest discriminatory accuracy of 84% with 91% sensitivity and 76% specificity., Conclusion: Computer-aided analyses of pulmonary nodules proved most useful for establishing the optimal criterion for differentiation of lepidic growth type lung neoplasms with good prognosis from those with poor prognosis., (© The Foundation Acta Radiologica 2013 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.)

Background: Ground-glass opacity (GGO) is reported to be characteristic to lepidic growth of neoplasm in subsolid nodules. In solid nodules of lung cancer, however, there is no characteristic feature to be reported., Purpose: To study if there are any thin-section CT findings characteristic to tumor histology or if they are only related to tumor size in solid nodules of the lung cancer., Material and Methods: This study included 106 solid peripheral lung cancers of 3 cm or smaller (56 adenocarcinomas, 33 squamous cell carcinomas, and 17 small cell carcinomas) in which 16-slice CT with 1 mm collimation was performed before surgery. Six morphologic findings (presence or absence of lobulation, coarse spiculation, air bronchogram, cavity, pleural tag, and pleural-based lesion) and four measurements (ratio of the greatest transverse and vertical diameter to the shortest transverse diameter and density of lobulation and coarse spiculation) on thin-section CT images were evaluated. Density of lobulation (coarse spiculation) was defined as the ratio of lobulation (coarse spiculation) number to the greatest transverse diameter of a nodule., Results: Air bronchogram (P < 0.01) was the only significant factor for predicting lung adenocarcinoma. The prevalence of air bronchogram was significantly greater in adenocarcinoma than in squamous cell carcinoma (P < 0.01) or small cell carcinoma (P < 0.01). As the tumor size advanced, significantly positive linear trends were seen in the prevalence of lobulation (P < 0.01), coarse spiculation (P < 0.01), and pleural tag (P < 0.01), and the mean values of density of lobulation (P < 0.01) and coarse spiculation (P < 0.01), while the significant negative linear trend was seen in the ratio of vertical diameter to the shortest transverse (P = 0.02)., Conclusion: Air bronchogram on thin-section CT is characteristic feature of solid adenocarcinoma of the lung. However, other thin-section CT findings are irrelevant to tumor histology and related only to tumor size.

Purpose: To investigate the clinicopathological features and prognosis in patients with adenocarcinoma of the lung with scattered consolidation (ALSC)., Materials and Methods: Between January 2006 and March 2010, 139 consecutive patients with lung adenocarcinoma of ≤3 cm, who underwent pulmonary resection for lung cancer, were investigated retrospectively. Radiologic classification was based on the findings of thin-section CT such as the presence of consolidation or ground-glass opacity (GGO). Type I (n=15) and Type II (n=14), showed a pure GGO and a mixed GGO with consolidation <50%, respectively. Type IV (n=38) and Type V (n=52) showed a mixed GGO with consolidation ≥50% and a pure consolidation, respectively. Type III (n=20) was the adenocarcinoma of the lung with scattered consolidation (ALSC). The clinicopathological features and prognosis of ALSC was investigated with comparative analysis and survival analysis., Results: Because of the similar recurrence rate for Type I and Type II (P=1.000), Type IV and Type V (P=0.343), we merged Type I and Type II as Type I+II, Type IV and Type V as Type IV+V, respectively. In the 20 (14.4%) patients with ALSC, lymph node metastasis was not observed, and it was rare in lymphatic invasion and vascular invasion. On the basis of IASLC/ATS/ERS 2011 classification, 80% of the ALSC were preinvasive lesions. In Noguchi classification, there was no significant difference between Type I+II and ALSC (P=0.260). The prognosis of ALSC was similar to Type I+II (P=0.408), but better than Type IV+V (P=0.040)., Conclusion: Adenocarcinoma of the lung with scattered consolidation (ALSC) on thin-section CT was a relatively favorable prognostic factor., (Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.)

Rationale and Objectives: The aim of this study is to assess the usefulness of computer-aided three-dimensional (3D) measurement of volume and computed tomography (CT) attenuation values of nodes for diagnosing nodal metastases of lung cancer., Materials and Methods: We measured three diameters, their ratios, volume, and CT values in 3D images of 191 nodes (64 malignant; 162 of <1 cm in short diameter) in 26 consecutive patients who underwent contrast-enhanced, thin-section, multidetector row CT before surgery. We separately studied statistically significant factors in a group of all nodes and in another group of nodes of <1 cm in short diameter with logistic modeling and evaluated their diagnostic accuracy., Results: Significant factors were CT values (P < .001) and short diameter (P = .001) for the total node group, and CT values (P = .030) and 3D volume (P = .035) for the <1 cm node group. Optimal 83% accuracy was obtained with a criterion of short diameter of >7.4 mm and CT values of >103 Hounsfield unit (HU) for the total node group, whereas optimal 76% accuracy was obtained with a criterion of 3D volume of >1282 mm(3) or CT values of >103 HU for the <1 cm node group., Conclusion: 3D measurement may be useful for diagnosing nodal metastases., (Copyright © 2013 AUR. All rights reserved.)

Background: Radiological discrimination of histologic subtypes of small peripheral adenocarcinoma of the lung is clinically important. Although there are many articles in which CT findings were used for this purpose, there are only a few reports on the capability of FDG PET-CT findings for histologic classification of this tumor., Purpose: To investigate the correlation between visual assessment or maximum standard uptake values (SUVmax) on F18-FDG PET-CT and histology grading of small peripheral adenocarcinoma of the lung., Material and Methods: Proportions of positive PET-CT diagnoses and SUVmax were retrospectively reviewed on 96 solitary pulmonary nodules of ≤2 cm in 90 consecutive patients. Tumors were classified into four groups according to Noguchi's classification (group 1 [n = 10], atypical adenomatous hyperplasia and type A tumors; group 2 [n = 12], type B tumors; group 3 [n = 42], type C tumors; group 4 [n = 32], types D, E, and F tumors). Proportions of positive PET-CT diagnoses and mean SUVmax of lesions among four groups were compared using trend tests to examine if there is a significant linear correlation with the progression of the histology grading of tumors. Then, an optimal threshold of SUVmax was proposed to best discriminate tumors of poor (groups 3 and 4) from good (groups 1 and 2) prognosis., Results: There was a significant linear trend for both visual assessment (P < 0.01) and SUVmax (P < 0.01). A SUVmax of 0.42 showed the highest accuracy of 84% with 95% sensitivity and 50% specificity for predicting tumors of poor prognosis. A SUVmax of 2.05 showed 100% specificity with 49% sensitivity, and 60% accuracy. Positive visual diagnoses showed accuracy of 83% with 90% sensitivity and 59% specificity., Conclusion: Visual assessment and SUVmax on PET-CT correlated well with the histology grading of small peripheral adenocarcinoma of the lung.

Imaging diagnostic methods except for mammograms are not recommended for follow-up of postoperative breast cancer patients in order to detect small recurrences because of the poor survival improvement in earlier randomized trials. However, the use of new imaging modalities may improve survival by detection of small isolated regional lymph node recurrences which are potentially curable. Between April 2006 and December 2008, we used PET-CT to find small recurrences in follow-up of 1,907 postoperative breast cancer patients. A total of 3,280 PET-CT imagings were performed. The median age at PET-CT imaging was 58 years, with a median 48-month interval from definitive surgery to the PET-CT imaging. Twenty-two patients were found to have isolated ipsilateral regional recurrences only by PET-CT (axillary node recurrences in 6, infraclavicular node recurrences in 5, supraclavicular node recurrences in 6, and parasternal node recurrences in 5). All of those recurrences were missed by palpation or were nonpalpable. The pathological lymph node status at the definitive surgery for the primary breast cancer of 22 patients with the isolated ipsilateral regional lymph node recurrences was positive in 17 patients. If patients are limited to those who had pathologically positive node(s) at definitive surgery, the incidence of patients with isolated regional lymph node recurrences found only by PET-CT would be 2.6% (17/663 patients). Seventeen other asymptomatic cancers including contralateral breast cancers were found only by PET-CT. Early detection of isolated loco-regional recurrences of breast cancer is suggested to result in improved survival. Therefore, the use of PET-CT in follow-up of postoperative node-positive breast cancer patients may improve their survival because of early detection of isolated regional lymph node recurrences which are still potentially curable, and screening of other asymptomatic cancers.

Objective: Sentinel node biopsy (SNB) is indicated for axillary lymph node metastasis-negative cases (N0), but clarification of the indication may increase treatment efficiency. Fluorine-18-labeled 2-fluoro-2-deoxy-D-glucose positron emission tomography (FDG-PET) may have a high positive predictive value in diagnosis of axillary lymph node metastasis., Methods: Ninety-two breasts/axillae were analyzed retrospectively in 90 patients (median age 54.6-year old, median primary tumor 1.7 cm). FDG-PET/computed tomography was used to indicate SNB in N0 cases. Axillary lymph node dissection (ALND) was performed in cases that were axillary lymph node metastasis-positive (PET N+) on FDG-PET/CT., Results: Seventy-four (80.4%) and 18 (19.6%) of the 92 axillae were diagnosed as metastasis-negative (PET N0) and PET N+, respectively, by FDG-PET/CT. SNB was performed in 51 of the 74 PET N0 axillae. ALND was performed in 23 PET N0 axillae (at the patients' request) and in all 18 PET N+ axillae. Of the 74 PET N0 axillae, 14 were metastasis-positive (pN+) and 60 were pN0 pathologically, and of the 18 PET N+ axillae, 13 were pN+ and five were pN0. The sensitivity and specificity of FDG-PET/CT for diagnosis of axillary metastasis were 48.1 and 92.3%, respectively, and the positive and negative predictive values were 72.2 and 81.1%, respectively., Conclusion: The positive detection rate on FDG-PET/CT was insufficient for determining an indication of SNB. However, use of an appropriate cut-off for SUV(max) (the positive rate was 90.9% with a cut-off of 2.0) and exclusion of surgically biopsied cases may achieve a clinically applicable positive detection rate.

Background: Magnetic resonance imaging mammography is performed to determine the extent of lesions and to detect occult lesions, but preoperative diagnosis by breast computed tomography (CT) is less common., Methods: We performed a retrospective study of detection of mammographically occult multiple lesions using breast CT. The subjects were 407 female patients (median age: 56 years old; median tumor size: 1.9 cm) with breast cancer who underwent preoperative, contrast-enhanced breast CT., Results: CT detected 73 incidental-enhanced breast nodules (median size: 0.8 cm) in 73 patients that were undetectable by conventional methods. Age, size of the main lesion or laterality of lesions did not differ between patients with and without incidental nodules, but the frequency of mastectomy was significantly higher in those with incidental nodules. Of the 73 incidental nodules, 22 (30%) were in the same quadrant as the main lesion, 26 (36%) were in other quadrants and 25 (34%) were in the opposite breast. On qualitative diagnosis by CT, 48 were suspected to be malignant (66%), 17 benign (23%) and eight non-specific (11%). In histological evaluation of 44 of the 48 nodules suspected to be malignant, 24 were malignant (invasive carcinoma: 22, non-invasive carcinoma: 2); of seven of the 17 nodules suspected to be benign, all were benign; and of three of the eight non-specific nodules, one was non-invasive carcinoma. The discovery rate of clinically and mammographically occult multiple lesions by preoperative breast CT was 6%., Conclusion: We conclude that breast CT is useful for the detection of occult lesions and choice of surgical procedure.

We report two cases of occult breast cancer in which masses were completely nonpalpable and positron emission tomography-computed tomography (PET-CT) was extremely helpful in identifying the primary tumor. Case 1 involved a 56-year-old woman with enlarged lymph nodes 3 cm in size in the axilla. Based on excisional biopsy, axillary lymph node metastasis of breast cancer was suspected but an obvious primary tumor in the breast was not identifiable on mammography, contrast-enhanced CT, or ultrasonography. Faint accumulation of fluorodeoxyglucose (FDG) was noted only on PET-CT, so the site was considered to be the primary site, and operation was performed. As a result of postoperative pathological examination, ductal carcinoma in-situ (DCIS) was diagnosed. Case 2 involved a 55-year-old woman with enlarged lymph nodes 3 cm in size in the axilla. Based on the excisional biopsy, axillary lymph node metastasis of breast cancer was suspected. In this case as well, an obvious primary tumor was not identifiable with palpation or mammography. On PET-CT, faint accumulation of FDG was noted in the vicinity of the CD regions, or upper and lower outer quadrants. When contrast-enhanced CT and ultrasonography were performed, a faint nodular opacity less than 1 cm in size corresponding to this site was found and diagnosed as the primary site, operation was subsequently performed. Pathologic diagnosis indicated invasive cancer. PET-CT is a helpful option for the diagnosis of occult breast cancer with primary sites that conventional imaging studies have difficulty identifying.

Objective: The aim of this study was to evaluate the efficacy of the objective radiologic analysis of high-resolution computed tomographic images of small peripheral non-small cell lung cancer and to select the candidates for curative limited resection., Methods: High-resolution computed tomographic images of 146 surgically resected T1 N0 M0 peripheral non-small cell lung cancers were analyzed by using National Institutes of Health image software and classified on the basis of the percentage of ground-glass opacity within the tumor., Results: Eighty-seven percent of tumors with ground-glass opacity ratios of 90% to 100% (type I) were diagnosed as noninvasive bronchioloalveolar carcinoma, whereas 55.6% of tumors with ground-glass opacity ratios of 50% to 89% (type II) consisted of adenocarcinoma. Tumors with ground-glass opacity ratios of 50% or more (type I/II) had no nodal involvement, whereas nodal metastases were identified in 20.0% of tumors with ground-glass opacity ratios of 10% to 49% (type III) and 24.4% of tumors with ground-glass opacity ratios of less than 10% (type IV). No tumors with ground-glass opacity ratios of 50% or more showed vessel infiltration, except for one lesion with a ground-glass opacity ratio of 50%. The 3-year disease-free survival was 97.7% for type I/II, 86.1% for type III, and 78.5% for type IV tumors., Conclusions: The objective quantitative radiologic analysis with National Institutes of Health image software exhibited a good correlation with the histologic classification, pathologic invasiveness, and postoperative outcome of small peripheral lung cancer. Patients with tumors that have ground-glass opacity ratios of greater than 50% are considered to be possible candidates for limited pulmonary resection.

Ten patients who underwent conventional coronary angiography (CA) were examined with both 8- and 16-slice multidetector-row computed tomography (MDCT) angiography within 6 months, and visibility and image quality of 16-slice MDCT-CA were compared with those of 8-slice MDCT-CA directly. In 136 segments determined by conventional CA, 101 (74.3%) and 126 (92.6%) segments were judged assessable by 8- and 16-slice MDCT-CA, respectively. Segment visibility in the right coronary and left circumflex arteries, as well as distal segments and small segments with diameters of <3.0 mm, was higher using 16-slice MDCT-CA than that of 8-slice MDCT-CA. As causes for invisibility in segments considered to be invisible, adjacent structures, as well as small diameters, were reduced by 16-slice MDCT-CA, suggesting that high spatial resolution contributes to higher visibility; however, nonassessable segments due to extensive calcium by 8-slice MDCT-CA were also judged nonassessable by 16-slice MDCT-CA.

The usefulness of multidetector-row computed tomography (MDCT) for visualization of coronary arteries has been reported; however, little is known about the diagnostic capability of noninvasive coronary angiography (CA) using 8-detector row CT. We investigated the visualization and diagnostic values of 8-slice MDCT-CA. Twenty-five consecutive patients who underwent conventional CA were investigated. The entire heart was scanned for approximately 20 seconds. Images were created using different reconstruction methods (half-scan and multisectors) followed by image creation during different time windows of the cardiac cycle. The data set containing the fewest artifacts was selected, then reformatted images were created and evaluated. In 348 segments in 25 subjects as determined by conventional CA, 258 segments (74.1%) were judged visible by MDCT-CA. Lower visibility was observed in segments with smaller diameters. Visibility in segments with diameters of > or =2.0 mm was 85.8% (212 of 247 segments). Patients with higher mean heart rates and a larger range of heart rate alteration during the breath-holding scan time had lower visibility. The most frequent cause for invisibility was "adjacent structure" (47%), followed by "small diameter" (33%), and "motion artifact" (16%), suggesting that motion artifacts were reduced by multisector reconstruction and search for the best-optimized time window. MDCT-CA detected 27 of 37 significant stenotic lesions (73%) that had a diameter reduction of >50% and correctly judged 226 of 311 segments (72.7%) as normal. Sensitivity, specificity, and accuracy of the visualized segments by MDCT-CA was 90% (27 of 30 segments), 99.1% (226 of 228 segments), and 98.1% (253 of 258 segments), respectively. Low visibilities in the left circumflex artery and distal and small segments are limitations of 8-slice MDCT-CA because of limited spatial resolution.

Objective: We studied the role of the first follow-up diagnostic CT for differentiating benign and malignant lesions in indeterminate solitary pulmonary nodules revealed at CT screening for lung cancer in which a total of 13,786 CT examinations (46% in women and 54% in men; 46% were smokers; mean age, 62 years) were performed., Materials and Methods: We reviewed thin-section CT findings on the initial diagnostic CT (lesion size; percentages of ground-glass-opacity areas of lesion; and presence or absence of lobulation, spiculation, air bronchogram, cavity, satellite lesions, pleural tag, concave margins, polygonal shape, and peripheral subpleural lesion) in 80 pulmonary nodules (36 malignancies and 44 benign lesions) of 80 patients. We evaluated changes in size (regression, no change, or growth) on the first follow-up CT performed 42-120 days (mean, 93 days) after the initial CT., Results: The greatest accuracy (81%) with 89% sensitivity and 75% specificity for determining malignancy was attained with a combined criterion of growth of lesions or predominantly ground-glass-opacity lesions. Of all criteria that were specific to malignancy, the greatest sensitivity (50%) was achieved with a combination of growth or no change in size of lesions and predominantly ground-glass opacity and no concave margins. Of all criteria that were specific to benign lesions, the greatest sensitivity (45%) was attained with a combination of lesion regression or polygonal shape., Conclusion: Follow-up CT findings were useful, and a combination of findings on initial CT and follow-up CT was optimal for differentiating benign and malignant pulmonary nodules.

Objective: We investigated the imaging findings and progression of replacement lung neoplasms that were revealed on thin-section CT and serial CT., Materials and Methods: We evaluated the age of patients and thin-section CT findings (lesion size; percentage of ground-glass opacity areas; and presence or absence of solid portions, lobulation, coarse spiculation, air bronchogram, cavity, multiplicity, and pleural tags) in 73 lesions (11 atypical adenomatous hyperplasias, 17 type A [Noguchi's classification], 18 type B, and 27 type C small peripheral adenocarcinomas). We compared the serial findings of 48 of 73 lesions on low-dose screening CT (n = 21) or thin-section CT (n = 27) obtained at a mean interval of 450 days (range, 85-951 days). Progression from atypical adenomatous hyperplasia through type A to type B and then to type C tumor was studied using trend tests., Results: A significant linear trend was seen for lesion size (r = 0.55; p < 0.001), percentages of ground-glass opacity areas (r = 0.75; p < 0.001), and the prevalence of lobulation (p < 0.001), spiculation (p = 0.001), air bronchogram (p = 0.023), cavity (p = 0.046), pleural tag (p < 0.001), and solid portions (p < 0.001). In general from serial CT assessment, lesions were recognized first as a ground-glass opacity nodule (56% of 48 lesions) with subsequent increase in size (75%), then solid portions appeared in the nodule (17%), and finally solid portions increased (23%) with occasional augmentation of tissue contraction (6%)., Conclusions: CT analysis revealed stepwise progression of replacement-type lung neoplasms.

Radiologic and pathologic findings correlate well in many pediatric neurologic disorders. However, there are some exceptions. Radiologic techniques are unable to visualize or identify pathologic changes in some diseases (e.g. status marmoratus and subdural fluid collection), whereas pathologic examination fails to clarify the histologic substrate of radiologic abnormalities in other conditions (e.g. Fukuyama-type congenital muscular dystrophy and neurofibromatosis type 1). Although studies to solve these issues have met with practical difficulties, important progress has recently been made on some disorders such as Fukuyama-type congenital muscular dystrophy and acute necrotizing encephalopathy.

Objective: We studied the prognostic importance of high-resolution CT (HRCT) findings in lung adenocarcinomas., Patients and Methods: HRCT findings (lesion size, percentage of ground-glass opacity (GGO) areas of lesion, and presence or absence of lobulation, coarse spiculation, air space, pleural tag, and multiplicity of lesion), clinical data (age and surgical method), and pathologic findings (tumor subtypes and presence or absence of nodal metastasis) in 64 consecutive patients with 64 peripheral adenocarcinomas of 20 mm or less (mean, 13 mm), including 36 women and 28 men with a mean age of 64 years were analyzed and correlated with survival of the patients using Kaplan-Meier method and stepwise Cox proportional hazards modeling. Follow-up periods of the patients ranged from 6 to 45 months (mean, 22 months). Tumors were classified into six subtypes (types A-F) according to tumor growth patterns defined by Noguchi et al., Results: Six (9%) of the 64 patients died of lung cancer. In univariate analyses, a significant difference was noted for lesion size (P=0.043), the percentage of GGO areas (P=0.005), and tumor subtypes (P=0.006). Lesion size of <15 mm (n=35), a lesion with GGO areas of >57% (n=36), and type A (n=16) or type B adenocarcinomas (n=16) indicated a significantly better survival. In multivariate analyses using these three parameters as independent variables, the percentage of GGO areas was the only significant independent factor for survival (P=0.044, relative risk=0.95)., Conclusion: GGO areas measured on HRCT may have an independent prognostic significance of small adenocarcinomas of the lung.

Objective: We evaluated the clinical usefulness of virtual CT gastroendoscopy (VCTGE)., Methods: The subjects were 124 patients with endoscopically identified gastric lesions. VCTGE images were obtained using a GE-Navigator. We evaluated VCTGE in the visualization of gastric lesions for their presence and morphology., Results: The detection rate of all gastric lesions by VCTGE was 76% (94 of 124 patients). The smallest detectable early gastric cancer was II c measuring 10 x 8 mm. The detection rates of each gastric lesion by VCTGE were 73% in early gastric cancer, and 90% in advanced gastric cancer. VCTGE imaging in the advanced gastric cancer was good in 12 (30%), fair in 25 (60%) and poor in 4 (10%). VCTGE imaging in early gastric cancer was good in 20 (46%), fair in 12 (27%) and poor in 12 (27%). The significance P level was 0.005 between the evaluation of the imaging of advanced and early gastric cancer., Conclusions: VCTGE visualized the characteristics of diverse gastric lesions and was considered useful for the detection and the diagnosis of these lesions.

Objective: The purpose of this study was to determine the correlation between high-resolution CT morphologic features of small peripheral lung adenocarcinomas and tumor growth patterns., Materials and Methods: We examined high-resolution CT morphologic features of 59 small, surgically resected peripheral lung adenocarcinomas (diameter, 6-20 mm) that were detected on screening for lung cancer using low-dose helical CT. Among these adenocarcinomas, 14 (24%) were visible and 45 (76%) were invisible on conventional chest radiography. The correlation between high-resolution CT morphologic features and tumor growth patterns was analyzed., Results: Sixteen (94%) of 17 type A (Noguchi's classification) adenocarcinomas appeared as nodules of pure ground-glass attenuation (high-resolution CT type I). Ten (71%) of 14 type B tumors appeared as heterogeneous, low-attenuation nodules (type II). Seven (29%) of 24 type C tumors appeared as nodules with ground-glass attenuation in the periphery and a high-density central zone (type III), and 12 (50%) of 24 type C tumors appeared as homogeneous nodules with soft-tissue density (type IV). Among tumors with a replacement growth pattern, the size and CT values of type C tumors were larger than those of type A or type B tumors (p < 0.05), whereas the percentage of ground-glass attenuation and retained air space in type C tumors was smaller than those in type A or type B tumors (p < 0.01). All (100%) four type D tumors appeared to be homogeneous nodules with soft-tissue density (type IV)., Conclusion: Small peripheral lung adenocarcinomas shown on CT exhibit four high-resolution CT patterns that corresponded to the histopathologic findings of different tumor growth patterns.

Purpose: To compare the effect of compression of spiral low-dose CT images by the Joint Photographic Experts Group (JPEG) and wavelet algorithms on detection of small lung cancers., Material and Methods: Low-dose spiral CT images of 104 individuals (52 with peripheral lung cancers smaller than 20 mm and 52 control subjects) were used. The original images were compressed using JPEG or wavelet algorithms at a ratio of 10:1 or 20:1. Five radiologists interpreted these images and evaluated the image quality on a high-resolution CRT monitor. Observer performance was studied by receiver operating characteristic (ROC) analysis., Results: There was no significant difference in the detection of cancers measuring 6 to 15 mm in uncompressed images and in those compressed by either of the algorithms, although the quality of images compressed at 20:1 with the wavelet algorithm was somewhat inferior. A lower diagnostic accuracy was noted using images compressed by the JPEG or wavelet algorithms at 20:1 in detecting lung cancers measuring 6 to 10 mm and cancers measuring from 6 to 15 mm with ground-glass opacity., Conclusion: Compression of low-dose CT images at a ratio of 10:1 using JPEG and wavelet algorithms does not compromise the detection rate of small lung cancers.

The aim of this study was to evaluate the usefulness of annual screening for lung cancer by low-dose computed tomography (CT) and the characteristics of identified lung cancers. Subjects consisted of 5483 general population aged 40-74 years, who received initial CT scans in 1996, followed by repeat annual scans for most subjects in 1997 and 1998, with a total of 13 786 scans taken during 1996-1998. Work-up examinations for patients with suspicious lesions were conducted using diagnostic CTs. The initial screening in 1996 detected suspicious nodules in 279 (5.1%) of 5483 subjects, and 22 (8%) were confirmed surgically to have lung cancer. Corresponding figures in 1997 and 1998 screening studies were 173 (3.9%) of 4425 and 25 (14%) of 173, and 136 (3.5%) of 3878 and 9 (7%) of 136, respectively. The sensitivity and specificity of detecting surgically confirmed lung cancer were 55% (22/40) and 95% (4960/5199) in 1996 and 83% (25/30) and 97% (4113/4252) in 1997 screening, respectively. 88% (55/60) of lung cancers identified on screening and surgically confirmed were AJCC stage IA. Our trial allowed detection of nearly 11 times the expected annual number of early lung cancers. Repeat CT allowed the detection of more aggressive, rapidly growing lung cancers, compared to those in the initial screening., (Copyright 2001 Cancer Research Campaign.)

We describe herein the CT features of atypical adenomatous hyperplasia (AAH) of the lung and its histopathological characteristics. Among 17,919 individuals screened for lung cancer by CT scanning, ten AAH nodules were detected in nine asymptomatic subjects. On high-resolution CT, the lesions measured from 6 x 6 mm to 15 x 17 mm and their CT number ranged from -500 to -760 HU. The AAHs appeared as round nodules with smooth and distinct borders and showed a ground-glass opacity. Plain chest radiographs failed to identify all lesions. Histopathologically, AAH lesions showed atypical epithelial cell proliferation along slightly thickened alveolar septa. Whereas it is often easy to differentiate these nodules from inflammatory and benign lung lesions, histopathological examination remains at present the only method to differentiate AAH from lung cancers.

The purpose of this study was to determine the effects of tumour density and tumour type on the visibility of small peripheral lung cancers on chest radiographs. We retrospectively evaluated the visibility of 63 small (< or = 20 mm) peripheral lung cancers on chest radiographs. 48 (76%) were detected in our low dose CT screening for lung cancer and 15 (24%) in routine clinical examination. Analysis was based on tumour optical contrast, gradient at the tumour margin, CT values and tumour type. There were 31 (49%) visible cancers and 32 (51%) invisible cancers on chest radiographs. Visible tumours had an optical density of 0.1-0.3 OD and a gradient of 0.03-0.11 OD mm-1. The mean size of visible tumour (14.3 mm) was larger than that of invisible tumour (11.1 mm; p < 0.001). The mean CT value (-140 HU) of visible tumour was higher than that of invisible tumour (-490 HU; p < 0.001). The detection rates of adenocarcinomas with lepidic growth (0% for type A, 29% for type B and 68% for type C) were less than those with hilic growth (100% for types D-F). All squamous and small cell carcinomas with hilic growth were visible on chest radiographs, but the numbers of each were small. In summary, tumour type influenced the contrast, gradient, CT values and margin of the tumour. Small adenocarcinomas with a lepidic tumour growth were less well seen on chest radiographs compared with small lung cancers with hilic tumour growth.

CT has recently been used in mass screening for lung cancer. Small cancers have been identified but the growth characteristics of these lesions are not fully understood. We identified 82 primary cancers in our 3-year mass CT screening programme, of which 61 were examined in the present study. The volume doubling time (VDT) was calculated based on the exponential model using successive annual CT images or follow-up CT images. All cases were also examined in the hospital by high resolution CT (HRCT). Lesions were divided into three types based on HRCT characteristics: type G (n = 19), ground glass opacity (GGO); type GS (n = 19), focal GGO with a solid central component; and type S (n = 23), solid nodule. 18 (95%) lesions of type G, 18 (95%) of type GS and 7 (30%) of type S were invisible on conventional chest radiographs. The mean size of the tumour was 10 mm, 11 mm and 16 mm for type G, type GS and type S, respectively. Most tumours (80%) were adenocarcinomas; 78% of these were GGO (type G and GS). Mean VDT values were 813 days, 457 days and 149 days for type G, type GS and type S, respectively; these are significantly different from each other (p < 0.05). Our results show that annual mass screening CT for 3 successive years resulted in the identification of a large number of slowly growing adenocarcinomas that were not visible on chest radiographs.

Since Castleman and Towne [Castleman and Towne, Hyperplasia of mediastinal lymph nodes, New Engl. J. Med. 250 (1954), 26-30] first described hyperplasia of the mediastinal lymph nodes in 1954, many cases of Castleman's disease have been reported. Lesions originating in the spleen arc extremely rare, and we here describe the imaging appearances for such a case, and discuss with a brief review of the literature.

Background/aims: Dysplastic nodules diagnosed pathologically exhibit various hemodynamic patterns. To evaluate these differences in their hemodynamics, we observed basement membrane formation of sinusoids., Methodology: For 12 low-grade dysplastic nodules, 24 high-grade dysplastic nodules and 16 hepatocellular carcinomas, both computed tomography during arterial portography and CT arteriography were performed preoperatively. Resected specimens were examined immunohistochemically for COL IV (type IV collagen) and laminin to observe basement membrane formation. We compared their hemodynamics on computed tomography during arterial portography and CT arteriography with the expressions of COL IV and laminin., Results: All of the low-grade dysplastic nodules were not hypervascular on CT arteriography, and negative for COL IV and laminin. All of the hepatocellular carcinomas were hypervascular on CT arteriography, and positive for COL IV and laminin. High-grade dysplastic nodules exhibit four hemodynamic patterns on CT during Arterial Portography/CT arteriography. All of 7 iso/iso and 5 iso/hypo nodules were negative for COL IV and laminin. Of the 9 hypo/hyper nodules, which exhibited hemodynamics similar to hepatocellular carcinoma, COL IV was identified in 7 and laminin identified in 8 nodules. Of the 3 hypo/hypo nodules, COL IV and laminin were identified in one., Conclusions: In high-grade dysplastic nodules, most cases exhibited a correlation between the hemodynamic patterns and the degree of the sinusoidal basement formation.

Purpose: To determine the optimal tube current for spiral CT for lung cancer screening., Material and Methods: Low-dose spiral CT images from 20 subjects were obtained with 50 mA, 25 mA, 10 mA and 5 mA tube currents. The accuracy in detecting 21 nodules measuring 3 to 14 mm in diameter was tested using receiver operating characteristics (ROC) to determine the diagnostic accuracy and statistical significance., Results: Compared with 50 mA, 25 mA showed no statistical difference. A significant difference was seen between 50 mA and 5 mA images and between 25 mA and 10 mA images, in the detection of lung parenchymal nodular lesions., Conclusion: Approximately 25 mA is the optimal tube current for the detection of pulmonary nodules as it allows a reduction of the radiation dose without sacrificing diagnostic accuracy.

Purpose: We reviewed the radiologic and clinical data in patients with metastatic disease to the thyroid gland and assessed the role of radiologic techniques in this disorder., Method: The findings on US (n = 11), CT (n = 7), MRI (n = 6), palpation or US-guided fine needle aspiration (FNA) biopsy, and clinical records were reviewed in 11 cases of pathologically verified metastatic tumors of the thyroid gland., Results: Five patients had palpable thyroid nodules and six had nonpalpable nodules discovered incidentally with imaging procedures. Three patients had no known malignancies at the time of diagnosis of thyroid tumors. Correct diagnosis was obtained in 10 of the 11 cases with FNA biopsy. Thyroid metastases were detected in all of the cases with US and MRI and six of the seven cases with CT. Thyroid metastases were solitary (n = 5) or multiple (n = 6), and about half of them measured <2 cm in diameter. These tumors typically had well defined margins and no calcification and sometimes had cystic portions. Multiple nodules within the same patient were radiologically quite similar to each other. On US, metastases appeared as hypoechoic or markedly hypoechoic areas without halo, on CT as low density areas, and on MRI as areas of varying signal intensities. Half of the metastases showed hypointensity on either T2-weighted images or gadolinium-enhanced T1-weighted images. The tumors involved lymph nodes in 10 cases and other remote organs in 5. Level I or II or parotid nodes were involved in six cases., Conclusion: These radiologic features may alert clinicians to a possibility of metastatic thyroid cancer. US combined with US-guided FNA biopsy is suitable for early diagnosis of metastases to the thyroid gland.

Conventional chest radiography (CXR) is a poor diagnostic tool for detecting lung cancers at a surgically curable stage. To determine the visibility of peripheral small lung cancers on CXR, we retrospectively examined the usefulness of CXR using a consecutive series of 44 cases detected on CT screening and later confirmed by histopathology. All cases had been detected by low dose CT during a population based screening trial for lung cancer. The control group consisted of 48 chest radiographs of normal subjects. Tumour diameters ranged from 6 mm to 45 mm, with 95% (42/44) < or = 20 mm, and 5% (2/44) > 20 mm. CXR failed to detect 77% (34/44) of all cancers, including 79% (33/42) < or = 20 mm and 50% (1/2) > 20 mm. Of the 42 lung cancers < or = 20 mm, 74% (31/42) were located in the well penetrated lung zones and 71% (22/31) of these were missed on CXR. 26% (11/42) were concealed by hilar vessels, mediastinum, heart or diaphragm, and all (11/11) of these were missed on CXR. 93% (39/42) of the lung cancers < or = 20 mm were adenocarcinomas and 79% (31/39) of these were missed on CXR. 7% (3/42) were epidermoid carcinomas or small cell carcinomas and 66% (2/3) of these were missed on CXR. The overall accuracy of interpretation on CXR for lung cancers was 61%, sensitivity was 23% and specificity 96%. Although there was an association between presence of lung cancer and positive reading of CXR (chi 2 test of association, p < 0.05), the percentage of positive readings was only 23%. Thus, CXR was poor at visualizing CT detectable lung cancers of < or = 20 mm diameter, which are usually of very low density, and cannot be relied upon for detection of surgically curable small lung cancer.

Computed tomography scans, including thin-section high-resolution computed tomography (HRCT), occasionally fail to differentiate between small non-cancerous nodules from lung cancers. We describe nine such lesions ( < 20 mm in diameter) initially identified through our screening program for lung cancer using CT scanning. Pathological diagnoses included nodular fibrosis (n = 4), granuloma (n = 1), cryptococcoma (n = 1), localised organising pneumonia (n = 1), inflammatory pseudo-tumour (n = 1) and sclerosing haemangioma (n = 1). High-resolution CT findings, together with MRI findings with contrast-enhanced dynamic studies, were retrospectively evaluated. Additional cases should be identified and radiologically characterised in order to reduce the number of non-cancerous tumours that are treated by unnecessary surgery.

We studied the CT and MR images of a patient with Japanese encephalitis. The first symptom was general malaise with high fever. The diagnosis of meningoencephalitis was made by spinal tap and clinical presentation. CT on the third day of illness showed no significant findings. MRI on the fifth day of illness demonstrated that the left thalamus and bilateral putamen were hyperintense on T2-weighted images. On CT one month later, the density in the thalamus and bilateral putamen was normal. MRI two month later showed high signal intensity only in the left thalamus. The patient recovered, but was judged to have dementia according to the simple dementia scale of Hasegawa. Flaccid paralysis was observed during the acute period.

The aim of this study was to clarify the thin-section CT features of small peripheral carcinomas of the lung on the basis of pathologic findings of tumor growth patterns. Thin-section CT and pathologic correlation was evaluated in 19 patients with surgically verified small peripheral carcinomas of the lung ( < 20 mm in size) that had been detected in a screening trial for lung cancer using spiral CT. Four thin-section CT types of nodules were observed: (a) type L1 (4 of 19, 21 %), a fairly well-defined nodule with ground-glass attenuation, corresponding to tumor lepidic growth without alveolar collapse; (b) type L2 (4 of 19, 21 %), a partly lobulated nodule with a low but inhomogeneous attenuation, corresponding to tumor lepidic growth with scattered foci of alveolar collapse; (c) type L3 (4 of 19, 21 %), an ill-defined nodule with an irregularly shaped higher-density central zone in a ground-glass attenuation peripheral zone, accompanied by convergence of the bronchovascular structures from the surrounding lung parenchyma, which corresponded to desmoplastic response in the central zone and to tumor lepidic growth in the peripheral zone; and (d) type H (7 of 19, 37 %), a well-defined nodule with a solid homogeneous attenuation, corresponding to tumor hilic growth. Thin-section CT features of small peripheral carcinomas of the lung can be classified into four types, based on the density distribution of the tumor, which reflect the histologic findings.

Rationale and Objectives: To investigate the pattern of physiological pulmonary geometric changes in the longitudinal direction due to respiration., Materials and Methods: Spiral CT scans of the lung were obtained in 20 normal subjects at maximal inspiration and expiration, each with a table feed time of 10 mm/sec, collimation of 10 mm, and continuous sections of 5 mm in thickness. Utilizing the pulmonary vessels or bronchi as the reference points and comparing the points of these structures shown on the CT images taken at both respiratory phases, the distance of excursion in the longitudinal direction during respiration was examined. Excursion of pulmonary structures was examined from the upper edge of the manubrium to the top of the diaphragm in three lung zones in the coronal direction., Results: A significant linear correlation between the distance from the upper edge of the manubrium to the structure and the distance of its excursion was found for all three lung zones (r = 0.84, p < 0.01 for the anterior zone; r = 0.89, p < 0.01 for the middle zone; r = 0.91, p < 0.01 for the posterior zone). The mean value of displacement in posterior zone was significantly greater (p < 0.01) than that in the middle zone, which was significantly greater (p < 0.01) than that in the anterior zone at each level., Conclusion: We have described the normal longitudinal displacement patterns of the pulmonary structures due to respiration. These findings may be applied to the diagnosis of pulmonary diseases.

Thirty-one cases of small hepatocellular carcinoma (HCC) under 3 cm in diameter underwent Spiral CT with bolus injection of contrast medium (Dynamic Spiral CT). Dynamic Spiral CT was compared with CT after intra-arterial injection of iodized oil (Lipiodol-CT). The detectability of 79 nodules of small HCC on early phase images of Dynamic Spiral CT was 49.4% (32.6% for those under 1 cm in diameter, 58.3% for 1-2 cm, 91.7% for 2-3 cm). The detectability of small HCCs above the hilum of the liver was better than that below the hilum. Five lesions were detected only on delayed CT images, but not on early phase CT images. Dynamic Spiral CT is useful for detecting hypervascular small HCCs, and both early phase and delayed CT images must be obtained.

Thalamic hyperdensity on computer-associated tomography (CT) has been reported as a disease-specific finding for GM2-gangliosidosis. However, a boy with the typical clinical symptoms and enzyme defect of infantile GM1-gangliosidosis had hyperdense thalamic lesions at 12 months of age. At the age of 34 months, the thalamus showed atrophy and the hyperdensity was restricted to the medial part of the thalamus, which exhibited increased intensity on T1-weighted and decreased intensity on T2-weighted images. Thalamic hyperdensity may be specific not only to GM2-gangliosidosis but also to GM1-gangliosidosis.

CT was used to measure changes in cerebral gray and white matter tissue densities associated with normal aging, using a cross-sectional design, in order to provide normative data for comparisons with abnormal aging such as dementias of Alzheimer's and vascular types. Cerebral compartmental densities were measured using plain CT, and their perfusion values were recorded during stable xenon inhalation (CT-CBF), among 81 neurologically and cognitively normal volunteers of different ages. Results led to the conclusion that cortical gray matter tissue densities progressively decline (polio-araiosis) after age 60. Cortical polio-araiosis is coupled with regional hypoperfusion but not with cortical atrophy. It is speculated that the cortical hypodensity identified by CT imaging parallels declines in cortical synaptic density, as reported from autopsy studies using anti-synaptophysin staining of cerebral cortex obtained from normal people above and below age 60. The coupling of cortical hypoperfusion with polio-araiosis is believed to reflect age-related reductions of cortical metabolic demands as reported by PET. During normal aging leuko-araiosis correlates directly with cortical atrophy, suggesting that anterograde axonal degeneration resulting from cortical neuronal dearborization play a role in its causation.

41 patients (30 men, 11 women, mean age 65.3 +/- 9.7 years) with probable ischemic vascular dementia diagnosed according to stated clinical criteria at least 3 months after hospital discharge and among a few nonhospitalized subjects with thorough clinical, neurovascular and neuroimaging workup have been followed for the past 7 years with serial measures of neurological and cognitive status and cerebral blood flow using stable xenon-enhanced CT. Cognitive impairments correlated with cerebral ischemia rather than CT measurements of infarcted brain volume. A minimum of one follow-up was required and follow-up intervals ranged from 4 months to 6.6 years (mean 3.4 +/- 1.6 years). 9 patients (22.0%) were lost to follow-up, 4.9% died, 9.8% became incapacitated by additional strokes, 2.4% by cancer and 4.9% moved away. Cross-sequential designs adjust for problems of attrition. Mortality rates of 1.4%/year during 1986-1993 are significantly lower than 2.0%/year between 1983 and 1986. Declines in mortality are attributed to control of risk factors and antiplatelet treatment of atherosclerotic cerebral vascular disease and anticoagulant treatment of patients with cardiogenic embolism.

The purpose of this study was to analyze the CT findings in lymphangitic carcinomatosis and to determine how the abnormalities seen on CT correlated with histologic findings and the results of pulmonary function tests. Accordingly, we reviewed CT findings in 20 proved cases and correlated them with histologic findings and with results of pulmonary function tests (available in 11). Special attention was given to the extent and degree of thickening of the peripheral and/or axial interstitium as seen on CT. In 15 of 20 patients, CT scans showed marked thickening of axial interstitium and subtle or no thickening of peripheral interstitium (four diffuse and 11 localized). In three cases, CT showed marked thickening of both axial and peripheral interstitium (two diffuse and one localized). In two cases, CT showed marked thickening of peripheral interstitium and subtle or no thickening of axial interstitium (one diffuse and one localized). These CT findings correlated with the pathologic findings. Marked impairment of vital capacity and alveolar-arterial oxygen gradient was observed in three patients (one with diffuse and peripheral interstitial thickening and two with diffuse and both peripheral and axial interstitial thickening). We conclude that CT findings in patients with lymphangitic carcinomatosis are variable and that marked impairment of pulmonary function occurs in patients with diffuse and peripheral interstitial thickening. Marked impairment of pulmonary function can be predicted from CT findings.

A retrospective analysis of the Magnetic resonance (MR) and CT findings in 18 untreated carcinomas of the oral cavity (7), oropharynx (2), hypopharynx (7), and larynx (2) was performed to assess the accuracy in evaluating extraorgan tumor spread and nodal involvement. Surgical and pathologic correlation was available for 13 primary tumors and nodal status was analyzed in 18. Nine primary tumors had extraorgan extension. MR had a tendency to be superior to CT in predicting tumor invasion of the cartilage and muscle. Sensitivity, specificity and accuracy for extraorgan spread of primary tumors were 89%, 100% and 92%, respectively, for MR and 78%, 75% and 77% for CT. Accuracy for nodal classification (83%) and carotid invasion (94%) of MR was equal to that of CT. CT was more sensitive than MR for demonstrating necrosis within the nodes and vice versa for detecting retropharyngeal nodes. MR imaging is a useful radiologic modality in evaluating extraorgan tumor spread and nodal levels of the head and neck carcinomas.

The radiologic findings in eight patients with parotid pseudotumors associated with Sjögren syndrome (CT in eight; MRI in two) were retrospectively analyzed and compared with the findings in three cases with malignant lymphomas. Diagnosis of pseudotumor was obtained by surgery in six cases and by fine-needle aspiration biopsy and radiologic follow-up in the remaining cases. Six cases (75%) had advanced disease and the remaining had early disease. Both solid (75%) and cystic (38%) masses were seen in the patients with pseudotumors. The masses were solitary in 25%, multiple in 75%, unilateral in 25%, and bilateral in 75%. All three lymphomas were solid masses. The lymphomatous masses were not reliably distinguished from the solid pseudotumors.

The neuroradiological findings in four patients with Tay-Sachs disease are described in three phases of the clinical course. The basal ganglia and cerebral white matter show low density on computed tomography and high signal intensity on T2-weighted magnetic resonance imaging in the initial phase. The caudate nuclei are characteristically enlarged and protrude into the lateral ventricles in the first and second phases. The cerebral white matter shows low density on the CT which varies in extent from the second to third phases, and the whole brain becomes atrophic in the last phase. Thus, central nervous system involvement in the disease may begin in basal ganglia as well as in cerebral white matter.

MR imaging and CT were performed prospectively in 35 patients with esophageal carcinoma to determine the resectability of the primary tumors, because at our institution patients with resectable tumors have surgery regardless of the presence of distant metastases. Tumors with evidence of aortic or tracheobronchial invasion on MR or CT were considered to be unresectable. Tracheobronchial invasion was diagnosed when the tumor extended into the lumen of the airway, and aortic invasion was diagnosed when the triangular fat space between the esophagus, aorta, and spine adjacent to the primary tumor was obliterated. Two patients were excluded because of suboptimal MR images produced by motion artifacts. Pathologic proof was obtained from either surgery or autopsy in 31 patients. Of these, six patients (19%) had proved unresectable tumors (three aortic invasion and three tracheobronchial invasion). In all six cases, these features were correctly detected with both MR and CT. One patient had false-positive findings on MR and CT. An indeterminate diagnosis was obtained with MR in three patients and with CT in four patients. These incorrect or indeterminate results were all related to the diagnosis of aortic invasion. No patient had a false-negative result. When indeterminate diagnoses were considered false-positive, sensitivity, specificity, and accuracy for resectability were 100%, 84%, and 87%, respectively, for MR and 100%, 80%, and 84%, respectively, for CT. We conclude that MR and CT have nearly the same accuracy in predicting resectability of tumors in patients with esophageal carcinoma.

We evaluated the sensitivity of CT for detecting mediastinal lymph node metastases in patients with nonsmall cell bronchogenic carcinoma. Computed tomography of 208 cases of surgically proven bronchogenic carcinoma from three institutes was evaluated retrospectively using specific diagnostic criteria. These consisted of two size thresholds for specific mediastinal node regions: 13 mm short transverse diameter for nodes in the subcarinal, precarinal, and tracheobronchial regions and 10 mm for other regions. Based on these criteria, the overall sensitivity of CT was 69%, specificity 94%, and accuracy 86% for detection of metastasis. In cases of adenocarcinoma, sensitivity was 61%, specificity 93%, and accuracy 81%, and in those of squamous cell carcinoma the respective values were 86, 94, and 92%. Comparison between the results using the present criteria with the former criterion of 10 mm short transverse diameter for all mediastinal nodes revealed that the number of false-positive cases decreased markedly. We conclude that more accurate CT evaluation of mediastinal lymph node metastasis in nonsmall cell bronchogenic carcinoma can be achieved with specific size criteria for specific mediastinal regions.

CT findings in 19 patients with anaplastic thyroid carcinoma were compared retrospectively with pathologic findings and the results of palpation. The carcinoma appeared as a large mass of low attenuation accompanied by dense calcification in 58% of the patients; there was necrosis in 74%. Often, adjacent structures were infiltrated. CT correctly showed tumor invasion of the carotid artery (7/7), internal jugular vein (9/10), larynx (5/6), trachea (8/10), esophagus (4/5), mediastinum (5/5), and regional lymph nodes (14/16). Seven patients (50%) had necrotic nodes. CT was superior to palpation in the detection of a primary tumor in one patient and of metastatic nodes in seven patients. It suggested a suitable place for biopsy in two patients, leading to a correct diagnosis. CT altered surgical planning in five patients with intrathoracic extension of the thyroid tumor, and in three patients with laryngeal or esophageal invasion of the tumor. CT can increase diagnostic accuracy in patients with anaplastic thyroid carcinoma by suggesting a likely diagnosis and by indicating an appropriate site for biopsy. It is indispensable in the planning of surgery for patients with this disorder.