Inherent variability of CT lung nodule measurements in vivo using semiautomated volumetric measurements.

OBJECTIVE: The objective of our study was to evaluate repeatability and reproducibility of lung nodule volume measurements using volumetric nodule-sizing software. MATERIALS AND METHODS: Fifty nodules, less than 20 mm in diameter, in 29 patients were scanned with 1.25-mm collimation using MDCT (time 1 = T1). During the same session, two additional scans, using identical technique, were obtained through each nodule (T2, T3). Three observers working independently then obtained volumetric measurements using a semiautomated volumetric nodule-sizing software package. Qualitative nodule characterization was also performed. The Bland-Altman method for assessing measurement agreement was used to calculate the 95% limits for agreement for nodule volumes at T1, T2, and T3. RESULTS: Automated nodule segmentation was successful in 438 (97%) of 450 measurements. Forty-three nodules were available for final evaluation. Twenty-six nodules had well-defined edges, and 17 had irregular or spiculated margins. Seventeen were freestanding, 16 were juxtapleural, and 10 were juxtavascular in location. Average nodule volume was 345.5 mm(3) (range, 49.3-1,434 mm(3)). The mean interobserver variability (repeatability) was 0.018% (SD = 0.73%), and the SD of the mean for the three contemporaneous scans (reproducibility) was 13.1% (confidence limits, +/- 25.6%). SD and confidence limits narrowed as volumes increased. CONCLUSION: Volumetric measurements show minimal interobserver variability (0.018%) but an interscan SEM of 13.1% (confidence limits, +/- 25.6%). Repeatability and reproducibility of volumetric measurements are better than those of linear measurements reported in the literature.

Variability of the pulmonary oblique fissures presented by high-resolution computed tomography.

The purpose of the study was to evaluate the radiological anatomy of oblique fissures (OFs) on high-resolution computed tomography (HRCT) scans. We retrospectively reviewed HRCT scans of 144 patients with normal lung parenchyma. The uppermost level of OFs with respect to the ribs, configuration (concave, straight, convex and others), orientation (medial or lateral facing), rotation and completeness of OFs were recorded. The most cranial level of the left OF was seen between the third and sixth ribs, and all but one were seen above or at the same level as the right OF. The uppermost extent of the OF was between the third and fourth intercostal space and seventh rib on the right lung. Only 2.2% of the right and 1.6% of the left OFs followed a parallel course to the ribs. The configuration of the OFs was generally concave in the upper zones (85.8% on the right and 72.1% on the left) and convex in the middle and lower lung zones (79.3% on the right and 73.9% on the left); 62.5% of the right and 59.7% of the left OFs were incomplete. Suprahilar portions of both OFs (98.9% on the right and 96.7% on the left) and the infrahilar portion of the right OF (54.2%) were generally facing laterally, whereas the infrahilar portion of the left OF was facing medially (80.9%). Angles of the MFs differed at the upper and lower levels. We detected reversal of 21 OFs in their craniocaudal course. In conclusion, the radiological anatomy of the right OF differs from the left OF. The uppermost extent of the left OF is almost always higher than the right. Thus, higher position of the right OF compared with the left almost always indicates a pathological process. Assessment of the angles of the OFs or comparison of the two sides cannot be used for the diagnosis of parenchymal disease like atelectasis. Occasionally, the classical propeller-like configuration is disrupted by the reverse course of the caudal part of the OF.

CT of deep venous thrombosis and pulmonary embolus: does iso-osmolar contrast agent improve vascular opacification?

PURPOSE: To prospectively compare the vascular attenuation achieved with the iso-osmolar dimeric contrast agent iodixanol with that achieved with the nonionic monomeric contrast agent iohexol for computed tomographic (CT) venography after CT pulmonary angiography. MATERIALS AND METHODS: Institutional review board approval and informed consent were obtained, and 51 consecutive patients undergoing CT pulmonary angiography and CT venography were recruited. A 130-mL dose of iodixanol 320 was injected intravenously at a rate of 4 mL/sec and followed by injection of 50 mL of saline. CT venography was performed after 3.5 minutes. From prior studies, 51 patients of similar weight were picked as control subjects. They received a similar iodine load with iohexol 300 and were studied with a similar technique. Section thickness was 1.25 mm for pulmonary emboli and 5 mm for deep venous thrombosis. Test and control group characteristics (ie, sex, age, and weight) were not significantly different (P >.05). Additionally, in test patients who had undergone CT pulmonary angiography and CT venography during the two preceding years, current and previously obtained CT scans were compared (ie, paired studies). Regions of interest were measured in four pulmonary artery and four lower extremity vein locations by two independent observers. RESULTS: Iodixanol increased average attenuation by 7 HU (P <.05) in the lower extremities and decreased average attenuation by 42 HU (P <.05) in the pulmonary arteries. In the 11 paired studies, similar results were obtained. CONCLUSION: Iodixanol caused a modest but statistically significant improvement in venous attenuation and a decrease in arterial attenuation. The diagnostic importance of this small increase in venous attenuation is not clear.

Apolipoprotein E gene polymorphism in renal transplant recipients: effects on lipid metabolism, atherosclerosis and allograft function.

INTRODUCTION: Atherosclerosis is a serious complication and leading cause of mortality in renal transplant recipients (RTRs). Hyperlipidemia may be associated with progression of renal disease and chronic allograft dysfunction. Similarities in the pathogenesis of glomerulosclerosis and atherosclerosis have been proposed. Apolipoprotein (apo) E gene code forms three major isoforms (E2, E3, and E4) with variable effects on lipid metabolism. PATIENTS AND METHODS: A total of 118 patients, at a mean age of 40 +/- 8 yr, were included in the study. Apo E genotyping was carried out on genomic DNA using polymerase chain reaction and restriction enzyme. Carotid artery intima media thickness and atherosclerotic plaques were evaluated by B-mode ultrasonography. The plasma levels of lipids and lipoproteins and acute phase reactants were also studied. Allograft function was evaluated by measuring serum creatinine and creatinine clearance values. RESULTS: The frequencies of E2, E3, and E4 alleles were 0.10, 0.78, and 0.12 respectively. Carotid artery atherosclerosis was found in 25% of E2 carriers, 30% of E3 carriers, and 57% of E4 carriers. Total cholesterol, total triglyceride, low-density lipoprotein, very low-density lipoprotein, apo B 100 levels were found to be higher in apo E4 carriers. Median apo A1 level was higher and allograft functions were better in apo E2 carriers (p < 0.05). Multiple regression analysis showed that allograft functions were negatively correlated with elevated acute phase reactants (p < 0.01) and only the age, but not the apo E genotypes, was an independent risk factor for atherosclerotic vascular disease (p < 0.01). DISCUSSION: The pathogenetic events linking lipid metabolism and allograft functions and development of atherosclerosis are complex and multifactorial in RTRs. Our results showed that apo E genotypes have influences on lipids, lipoproteins and allograft functions. The ultimate role of apo E4 gene polymorphism as a risk factor for development and progression of atherosclerosis in RTRs should be sought in further studies.

[Radiologic investigation of vertebrobasilar insufficiency and quantification of vertebrobasilar flow with magnetic resonance imaging]. / Vertebrobaziler yetmezligin tanisinda radyolojik inceleme ve vertebrobaziler akimin MRG ile ölçümü.

PURPOSE: To evaluate the contribution of cervical spine radiograms, Doppler US, cervical and cranial MRI, MRA and two dimensional quantification flow in the diagnosis of vertebrobasilar insufficiency. MATERIALS AND METHODS: We prospectively examined 25 patients having signs of vertebrobasilar insufficiency (16 females and 9 males, aged 34 to 74 years) and 25 controls of the same age and sex with MRI, MRA, Doppler US and cervical radiograms. Cervical spine radiograms were evaluated for the presence of degenerative changes, osteophytes and loss of height. The flow velocities of the basilar artery and vertebral arteries were measured with two dimensional quantification flow, using time-velocity graphics achieved by means of a region of interest drawn on transverse sections of the vessels. Posterior circulation in farcts and slow flow in vertebrobasilar system arteries were investigated on brain MR images and the presence of cervical osteophytes, spinal cord compression and the effect of the presence of degenerative changes on vertebral arteries were evaluated on cervical MR images. Paired samples T-test, independent samples T-test, Wilcoxon W, Mann-Whitney U and chi-square tests were used for statistical analysis. The significance level was taken at p below 0.05. RESULTS: From the statistical analysis, we found that there were more pathologic findings on MRA within the patient group compared with the controls (p = 0.002). The velocities measured by MRI were significantly affected by the presence of unknown bright objects on brain MR images, osteophytes on cervical MR images, loss of height and the presence of osteophytes on radiograms in patients having VBI signs, when compared to the controls. In both groups, the measurements of flow velocity in vertebral arteries by Doppler US did not correlate with the measurements by two dimensional quantification flow. CONCLUSION: Among the methods we used in our study, MRA was the most specific in the diagnosis of patients with vertebrobasilar insufficiency. However, two dimensional quantification flow can be used as a noninvasive but indirect method to investigate the influence of several factors on the hemodynamics.

Evaluation of breast microcalcifications according to Breast Imaging Reporting and Data System criteria and Le Gal's classification.

INTRODUCTION/OBJECTIVE: Our aim was to evaluate the positive predictive value (PPV) of the analysis of breast microcalcifications according to Breast Imaging Reporting and Data System (BI-RADS) and Le Gal's classification in identification of malignancy, and to assess the interobserver agreement using these criteria. METHODS AND MATERIAL: Eighty-two patients with breast microcalcifications on their screening mammograms underwent surgical excision after a needle localization at our institution between July 1993 and June 2000. The mammograms were examined by two experienced mammographers retrospectively and independently. Each observer noted the morphology, distribution, associated findings, final assessment categories of microcalcifications according to BI-RADS criteria and the morphologic type of microcalcifications according to Le Gal's classification. The PPVs for each radiologist and the interobserver agreement were determined by using these data and histologic findings. RESULTS: Histopathologic results yielded malignancy in 25 (30%) cases. The evaluation of microcalcifications according to BI-RADS criteria revealed PPVs of 17% and 25% for category 4 lesions, and 68% and 44% for category 5 lesions. In the assessment of microcalcifications according to Le Gal's classification, the PPV of type 4 lesions was 45% (for both observers), whereas the PPVs of type 5 lesions were 70% and 50%. The interobserver agreement was fair in evaluation of morphology of microcalcifications (kappa:0.31), distribution of microcalcifications (kappa:0.29), final assessment categories (kappa:0.27), and moderate in evaluation of associated findings (kappa:0.48) by using BI-RADS lexicon. It was higher for the assessment of milk of calcium and round microcalcifications than other typically benign microcalcifications, and for fine linear or fine linear branching microcalifications than other probably malignant calcifications. There was a fair interobserver agreement (kappa:0.30) in the description of the morphologic type of microcalcifications according to Le Gal's classification. DISCUSSIONS AND CONCLUSION: In our study, both BI-RADS lexicon and Le Gal's classification did not succeed expectedly in reducing the ambiguity in assessment of breast microcalcifications. Further studies and perhaps development of new methods are required to improve accuracy and standardization in mammographic interpretation.

Mammographic features of nonpalpable spiculated lesions.

OBJECTIVE: To evaluate the mammographic features of nonpalpable spiculated lesions in order to find differentiating findings between malignant and benign pathologies. MATERIALS AND METHODS: Standard mammograms of 27 patients with 28 nonpalpable spiculated lesions were evaluated retrospectively. Two dimensions of dense centre of the spiculated lesions were measured and the mean dimensions were compared in analysing the malignant and benign features. Fine radiolucent lines between dense spicules were noted. RESULTS: Thirteen spiculated lesions (46.4%) were malignant and 15 were benign. Eleven malignant lesions (84.6%) have dense centre larger than 5 mm, whereas only four benign lesions (26.7%) had a dense core larger than 5 mm. There were fine radiolucent lines parallel to dense spicules in 5 malignant lesions (38.5%) and in 13 benign lesions (86.7%). Only one invasive carcinoma and one radial scar with florid ductal epithelial hyperplasia and papillomatosis had punctate calcifications. The sensitivity and specificity of the dense core larger than 5 mm for malignancy were 84.6% and 73.3%, respectively. The sensitivity of radiolucent lines for benign lesions was 86.7% and the specificity was 61.5%. CONCLUSION: When the dense centre of a nonpalpable spiculated lesion is larger than 5 mm, the probability of malignant pathology increases. The fine radiolucent lines between dense spicules may indicate benign etiology. However, there is no reliable mammographic feature differentiating benign spiculated lesions from carcinomas. Therefore, all of them should be diagnosed pathologically unless they are postsurgical.

CT for the diagnosis of venous thromboembolic disease.

Spiral CT, venous ultrasound, ventilation-perfusion scanning, and D-dimer tests are routinely used in the diagnosis of venous thromboembolic disease. Advances in multidetector spiral CT and the combination of CT pulmonary angiography and venography as a one-step evaluation of venous thromboembolic disease have markedly improved detection of subsegmental emboli and deep pelvic venous thrombi and decreased the role of conventional pulmonary angiography. As CT has improved, many have questioned what "gold standard" CT should be compared with. Recent clinical outcome studies suggest that CT results are as good as pulmonary angiography and conventional imaging algorithms. Because the sensitivity of CT pulmonary angiography now exceeds 85%, it also appears that it is also more cost effective than other diagnostic approaches.

CT for thromboembolic disease.

Pulmonary embolism (PE) and deep venous thrombosis (DVT) constitute the two clinical manifestations of venous thromboembolic disease (VTE). The recent innovation of computed tomography venography (CTV) in conjunction with CT pulmonary arteriography (CTPA) provides a single noninvasive diagnostic test that can evaluate both components of VTE. PE is often an underestimated, underdiagnosed, and, consequently, undertreated disease entity. Herein, we review the epidemiology of thromboembolic disease, the diagnostic algorithm used in evaluation of patients with suspected VTE, and protocols for performing CTPA and CTV. Interpretation of these examinations is discussed in detail, because CTPA may pose new challenges to the practicing radiologist.

Venous thromboembolic disease: where does multidetector computed tomography fit?

Introduction of helical CT started a new era in the diagnosis of PE. It is noninvasive and readily available. Developments in helical CT technology (particularly introduction of multidetector scanners) improved image quality by decreasing the scanning time and slice thickness. With the addition of indirect CT venography to CT pulmonary angiography, CT also took the role of venous ultrasound, thus creating a single examination for diagnosis of VTD. On the other hand, CT is not perfect at all circumstances, especially in the evaluation of subsegmental arteries. Careful selection of patients for imaging studies will save time, cost, and radiation.

Comparison of low-dose and standard-dose helical CT in the evaluation of pulmonary nodules.

The purpose of this study was to investigate the diagnostic accuracy of low-dose helical computed tomography by comparing the number of nodules detected at low- and standard-dose CT. The prospective study included 25 patients who were referred to CT scan for the assessment of pulmonary metastases. All patients underwent CT examinations at both standard- (200 mA, 120 kV, collimation 5 mm, table feed 10 mm per rotation) and low-dose (50 mA, 120 kV, collimation 5 mm, table feed 10 mm per rotation). The number of nodules detected at each protocol was recorded. The size of the nodules was measured electronically and categorized as <3, 3-4.9, 5-6.9, 7-9.9, and >/=10 mm. Finally, the nodules detected at only standard- or low-dose CT were assessed for the underlying causes of discrepancy. In 25 patients, 533 nodules were detected at standard-dose, whereas 518 nodules were observed at low-dose CT. There were no statistically significant differences in the number of nodules detected at standard- or low-dose CT ( p>0.05). Four hundred ninety-one (87.7%) nodules were detected at both standard- or low-dose CT, 42 (7.5%) nodules were observed only at standard-dose CT, and 27 (4.8%) nodules were seen only at low-dose CT. The sensitivity of low-dose CT was 92.5% for all nodules, 88.1% for nodules <5 mm, and 97.4% for nodules >/=5 mm. No significant image artifact interfering with nodule detection was observed at low-dose CT. The low-dose CT protocol used in this study provided images of adequate quality; thus, it can be used reliably in the detection or exclusion of pulmonary nodules.

Renal involvement in multifocal osteosarcoma.

A rare case of multifocal osteosarcoma metastatic to kidney, lung and lymph nodes is presented. Radiological findings included multiple foci of sclerotic lesions involving the axial and peripheral skeleton, a heterogeneous renal mass with areas of calcification, multiple pulmonary metastases with pneumothorax, and partially calcified enlarged mediastinal and abdominal lymph nodes.

Treatment and follow-up of pulmonary alveolar microlithiasis with disodium editronate: radiological demonstration.

A 9-year-old girl with pulmonary alveolar microlithiasis is presented. She was asymptomatic except for failure to thrive. Plain chest radiographs on admission showed sand-like opacities with calcific densities throughout both lung fields, predominantly in the lower zones. A black pleural line was also seen between the ribs and lung parenchyma. High-resolution CT (HRCT) revealed diffuse ground-glass opacities throughout both lungs, micronodular densities, interlobular septal thickening, linear calcifications along the pleura and a few scattered subpleural cysts. Disodium editronate, which is known to inhibit the microcrystal growth of hydroxyapatite, was started at 10 mg/kg per day orally. After 1 year of therapy, considerable regression of the calcific densities was detected on chest radiographs and HRCT scans.

Anatomy of the minor fissure: assessment with high-resolution CT and classification.

The aims of this study were to investigate the anatomy of the minor fissure and its variations on high-resolution CT (HRCT) sections and to propose a detailed classification. The prospective study included 67 patients who were referred to CT for various indications. High-resolution CT examinations (1.5-mm collimation) were obtained through the region of the minor fissure. The CT scans were assessed for the presence, completeness, and configuration of the minor fissure. Various configurations of the minor fissure were classified into four major types, based on whether the highest portion of the middle lobe upper surface was medial (type I), lateral (type II), posterior (type III), or central (type IV). Minor fissure was identified in 65 (97%) of 67 patients, and absent in 2 (3%) cases. The fissure was incomplete in 35 (54%) of 65 patients. Type-I minor fissure is seen in 28 (43%) patients, type II in 22 (34%), type III in 5 (8%), and type IV in 2 (3%) patients. Because the majority of the fissure was absent in 8 (12%) of 35 patients with incomplete fissure, they were considered indeterminate. Comprehensive knowledge of the various configurations of the minor fissure is helpful in correct localization of a lesion and its extension. In equivocal cases, limited thin-section CT scans through the fissure delineate the anatomy more clearly and provide greater degree of precision in localizing pulmonary lesions.