The purpose of this study was to determine the morphological and dynamic features of normal pulmonary valve by using dual-source CT. Thirty patients who underwent dual-source CT angiography with right ventricular outflow tract well-opacified were enrolled. Ten phases of images were reconstructed at 10% R-R interval, and pulmonary valve area and pulmonary annular diameter were measured on all 10 phases. As the pulmonary valve opened, its orifice appeared as oval or proximate triangle. As the pulmonary valve closed, it appeared as "Y-shape". Pulmonary valve opened from 10% to 30% phases, with maximum pulmonary valve area of (4.74 +/- 0.69) cm2 in 10% phase. Pulmonary valve closed from 40% to 90% phases. Pulmonary annular diameter varied with cardiac cycle, with maximum pulmonary annular diameter of (2.36 +/- 0.24) cm in 0% phase and minimum pulmonary annular diameter of (1.82 +/- 0.32) cm in 40% phase (P < 0.001). The proximal phase for assessing pulmonary valve was 70% phase. Dual-source CT may evaluate the morphological and dynamic features of normal pulmonary valve.
Adult ; Female ; Humans ; Iohexol ; analogs & derivatives ; Male ; Middle Aged ; Pulmonary Valve ; anatomy & histology ; diagnostic imaging ; physiology ; Tomography, Spiral Computed ; methods

OBJECTIVE: To evaluate the nature and imaging appearance of incidental enhancing breast lesions detected on a routine contrast-enhanced chest CT. MATERIALS AND METHODS: Twenty-three patients with incidental enhancing breast lesions on contrast-enhanced chest CT were retrospectively reviewed. The breast lesions were reviewed by unenhanced and enhanced CT, and evaluated by observing the shapes, margins, enhancement patterns and backgrounds of breast lesions. A histopathologic diagnosis or long-term follow-up served as reference standard. RESULTS: Sixteen (70%) patients had malignant breast lesions and seven (30%) had benign lesions. In 10 patients, the breast lesions were exclusively detected on contrast-enhanced CT. Using unenhanced CT, breast lesions with fibroglandular backgrounds were prone to be obscured (p < 0.001). Incidental primary breast cancer showed an non-significant trend of a higher percentage irregular margin (p = 0.056). All of the four incidental breast lesions with non-mass-like enhancement were proven to be malignant. CONCLUSION: Routine contrast-enhanced chest CT can reveal sufficient details to allow for the detection of unsuspected breast lesions, in which some cases may be proven as malignant. An irregular margin of incidental enhancing breast lesion can be considered a suggestive sign of malignancy.
Aged ; Breast Diseases/radiography ; Breast Neoplasms/*radiography/secondary ; *Contrast Media ; Female ; Humans ; *Incidental Findings ; Iohexol/*analogs & derivatives/diagnostic use ; Middle Aged ; *Radiography, Thoracic ; *Tomography, X-Ray Computed

OBJECTIVE: To evaluate the effect of thin overlapping reconstruction on the attenuation of small (< or = 3 cm) renal cysts in the nephrographic phase of multidetector CT (MDCT). MATERIALS AND METHODS: We scanned a phantom kidney containing spheres of various sizes (10, 20, and 30 mm) using both 4- and 16-channel MDCT scanners, and reconstructed images with various slice thickness (T, mm) and intervals (I, mm). The attenuation increase (AI) was measured for each sphere in 240-HU diluted solution of contrast material and compared with the attenuation in 35-HU solution. RESULTS: On the 4-channel MDCT, thin overlapping reconstruction (T/I = 3/1, compared with 5/5) lowered the AI as much as 17 HU in the 10 mm-sphere and 6 HU in the 20 mm-sphere (p < 0.05). Thin slicing alone was also effective; however overlapping alone was not. On the 16-channel MDCT, AI in the 10 mm-sphere was significantly lower than on the 4-channel MDCT with T/I = 5/5 (p < 0.05), however thinner slicing or overlapping did not affect the attenuation significantly in all of the spheres. CONCLUSION: The effect of thin overlapping reconstruction on minimizing falsely elevated attenuation in the nephrographic phase was significant only in cysts < or =20 mm on the 4-channel MDCT.
Tomography, X-Ray Computed/*methods ; *Radiographic Image Interpretation, Computer-Assisted ; Phantoms, Imaging ; Kidney Diseases, Cystic/*radiography ; Iohexol/analogs & derivatives/diagnostic use ; Humans ; Contrast Media

OBJECTIVETo investigate the feasibility of using lower iodine concentration (270 mgI/ml) contrast medium, lower X-ray tube voltage (100 kVp) and iterative reconstruction (IR) to reduce both iodine load and radiation dose but keep the image quality of coronary CT angiography (CCTA).

METHODSA total of 80 consecutive patients with suspected coronary artery disease were prospectively assigned to one of two groups via computer central system from January to May 2013. The control group (n = 40) was scanned using dual-source CCTA protocols of 120 kV, 370 mgI/ml Iopromide and filtered back projection reconstruction with a vascular algorithm (B26f). The study group (n = 40) was scanned using 100 kV, 270 mgI/ml Iodixanol and sinogram affirmed iterative reconstruction with a vascular algorithm (I26f). Other scan parameters and contrast injection protocol were similar between the two groups. Attenuation in the ascending aorta and coronary arteries along with image noise were measured. Images were reconstructed, measured and graded, and iodine load and effective radiation dose were calculated.

RESULTSThe body mass index ((25.3 ± 3.0) kg/m² vs. (25.4 ± 3.0)kg/m², P = 0.852), image quality scores (4.70 ± 0.52 vs. 4.63 ± 0.59, P = 0.545), mean signal-to-noise ratios (22.2 ± 5.5 vs. 23.6 ± 5.8, P = 0.277), and contrast-to-noise ratios (35.6 ± 17.6 vs. 41.1 ± 17.6, P = 0.163) were similar between the control group and study group. Mean iodine loads were significantly reduced in the study group ((18.49 ± 0.75)g) compared to control group ((25.27 ± 0.94)g), P< 0.001). Mean effective radiation doses were also significantly reduced in the study group ((2.31 ± 0.73) mSv) compared to that in control group ((3.52 ± 1.16) mSv), P< 0.001).

CONCLUSIONUse of low X-ray tube voltage and iterative reconstruction allows lower iodine load and effective radiation dose application at CCTA without image quality reduction.

Algorithms ; Aorta ; Body Mass Index ; Contrast Media ; Coronary Angiography ; Coronary Artery Disease ; Feasibility Studies ; Fluoroscopy ; Humans ; Injections, Intravenous ; Iodine ; Iohexol ; analogs & derivatives ; Tomography, X-Ray Computed ; Triiodobenzoic Acids

OBJECTIVE: The aim of this study was to use fractal dimension (FD) analysis on multidetector CT (MDCT) images for quantifying the morphological changes of the pulmonary artery tree in patients with pulmonary hypertension (PH). MATERIALS AND METHODS: Fourteen patients with PH and 17 patients without PH as controls were studied. All of the patients underwent contrast-enhanced helical CT and transthoracic echocardiography. The pulmonary artery trees were generated using post-processing software, and the FD and projected image area of the pulmonary artery trees were determined with ImageJ software in a personal computer. The FD, the projected image area and the pulmonary artery pressure (PAP) were statistically evaluated in the two groups. RESULTS: The FD, the projected image area and the PAP of the patients with PH were higher than those values of the patients without PH (p < 0.05, t-test). There was a high correlation of FD with the PAP (r = 0.82, p < 0.05, partial correlation analysis). There was a moderate correlation of FD with the projected image area (r = 0.49, p < 0.05, partial correlation analysis). There was a correlation of the PAP with the projected image area (r = 0.65, p < 0.05, Pearson correlation analysis). CONCLUSION: The FD of the pulmonary arteries in the PH patients was significantly higher than that of the controls. There is a high correlation of FD with the PAP.
Adult ; Aged ; Case-Control Studies ; Contrast Media/diagnostic use ; Female ; *Fractals ; Humans ; Hypertension, Pulmonary/*radiography ; Iohexol/analogs & derivatives/diagnostic use ; Male ; Middle Aged ; Pulmonary Artery/*radiography ; Radiographic Image Interpretation, Computer-Assisted/*methods ; *Tomography, Spiral Computed

OBJECTIVE: We wanted to evaluate the mural changes by CT on the follow-up examination of patients with active Takayasu arteritis. MATERIALS AND METHODS: The study included 18 patients, (4 males and 14 females), with active Takayasu arteritis. A total of 44 CT examinations were done during the follow-up period (mean: 55.6 months). At the time of the last follow-up CT, the disease, on the basis of the erythrocyte sedimentation rate (ESR), was found to be inactive in five patients and the disease was active and persistent in 13 patients. The thickness and CT attenuation of the aortic wall on the precontrast, arterial and venous phases were measured on the initial and the follow-up CT examinations. The ratio of the mural attenuation over that of the back muscle on the initial CT was compared with the ratio found on the follow-up CT. RESULTS: The initial CT findings included high density and calcifications of the aortic wall in the precontrast images and a thickened wall with enhancements in the arterial and the venous phases. A low-attenuation ring was demonstrated in the venous phase in 15 patients (83%). On the follow-up evaluation, the mean mural thickness decreased significantly from 4.1 mm to 2.4 mm. The mean mural attenuation ratio in the venous phase decreased significantly from 1.9 to 1.3 (p = 0.001). The low attenuation ring was identified in seven patients (39%) who had only with active, persistent Takayasu arteritis. CONCLUSION: The mural changes demonstrated by the follow-up CT evaluations for the patients with active Takayasu arteritis included a decrease of the mural thickness and enhancement, disappearance of the low-attenuation ring on the venous phase, and an increase of the mural attenuation and calcification on the precontrast phase.
Adolescent ; Adult ; *Aortography ; Blood Sedimentation ; Child ; Contrast Media/administration & dosage ; Female ; Follow-Up Studies ; Humans ; Iohexol/administration & dosage/analogs & derivatives ; Male ; Middle Aged ; Pulmonary Artery/radiography ; Retrospective Studies ; Takayasu Arteritis/*radiography ; Tomography, X-Ray Computed

This study was undertaken to compare renal damage, as determined by serum creatinine and degree of apoptosis, caused by iodinated contrast or gadolinium in an acute renal failure (ARF) rat model. Rats were divided into three groups; controls (n=3), a CT contrast medium group (n=9), and an MR contrast medium group (n=9). The CT and MR groups were further subdivided into three groups, namely, low, standard, and high dose subgroups. Renal function was evaluated by determining serum creatinine levels; before ARF, and 48 hr after ARF and contrast administration. Apoptosis was assayed by terminal deoxynucleotidyl transferasemediated dUTP nick-end labeling (TUNEL). No significant creatinine level differences were observed between the CT and MR groups (p=0.116). Degrees of apoptosis in the renal cortex and medulla were more severe in the CT contrast medium group than in the control or MR contrast medium group (p<0.05). The study shows that CT contrast medium did not aggravate renal function more so than MR contrast medium in this ARF rat model. However, apoptosis examination in the renal cortex and medulla indicated that CT contrast medium induced more severe apoptosis than MR contrast medium (p<0.05). We conclude that CT contrast medium can be used for renal imaging studies when subjects are well hydrated and preventive medication is administered.
Animals ; Apoptosis/*drug effects ; Contrast Media/adverse effects ; Creatine/*blood ; Female ; Gadolinium DTPA/*adverse effects ; Iohexol/adverse effects/*analogs and derivatives ; Kidney/*drug effects/*pathology ; Kidney Failure, Acute/*blood/pathology/radiography ; Male ; Rats ; Rats, Sprague-Dawley ; Research Support, Non-U.S. Gov't

OBJECTIVE: We wanted to evaluate the CT findings of epithelial origin ovarian carcinoma according to the degree of histologic differentiation. MATERIALS AND METHODS: This study enrolled 124 patients with 31 well differentiated, 44 moderately differentiated and 95 poorly differentiated carcinomas with epithelial origin. The CT images were retrospectively evaluated with regard to bilateral ovarian involvement, the tumor's nature, lymphadenopathy, adjacent organ invasion, peritoneal tumor seeding, a large amount of ascites and distant metastasis. In cystic, predominantly cystic and mixed tumors, the tumor wall, septa, papillary projection and necrosis in the solid portion were assessed. RESULTS: Bilateral ovarian involvement was more common in the poorly (48%) and moderately (42%) differentiated carcinomas than in the well differentiated carcinomas (7%) (p < 0.05). The frequency of a predominantly solid or solid nature was greater in the moderately and poorly differentiated carcinomas than in the well differentiated carcinomas (p < 0.0001). In the 87 tumors with a cystic, predominantly cystic or mixed nature, septa greater than 3 mm, papillary projection and necrosis in the solid portion were more common in the poorly differentiated carcinoma (91%, 91% and 77%, respectively) than in the moderately (64%, 68% and 34%, respectively) and well differentiated carcinomas (63%, 47% and 27%, respectively) (p < 0.05). Lymphadenopathy, organ invasion, tumor seeding and a large amount of ascites were more common in the poorly differentiated carcinomas (38%, 27%, 73% and 69%, respectively) than in the moderately (13%, 10%, 48% and 45%, respectively) and well differentiated carcinomas (3%, 0%, 10% and 17%, respectively) (p < 0.05). CONCLUSION: Epithelial origin ovarian carcinoma shows different CT findings according to the degree of histologic differentiation.
Ascites/radiography ; Carcinoma/*pathology/*radiography ; Contrast Media ; Female ; Humans ; Iohexol/analogs & derivatives ; Iopamidol ; Lymphatic Metastasis ; Middle Aged ; Neoplasm Invasiveness ; Ovarian Neoplasms/*pathology/*radiography ; Retrospective Studies ; Tomography, Spiral Computed/*methods

OBJECTIVE: The purpose of this study was to describe the myocardial enhancement patterns in patients with myocardial infarction using two-phase contrast-enhanced multidetector-row computed tomography (MDCT). MATERIALS AND METHODS: Twenty-three patients with clinically proven myocardial infarction (17 acute myocardial infarction [AMI] and 6 chronic myocardial infarction [CMI]) were examined with two-phase contrast-enhanced ECG-gated MDCT. The presence, location, and patterns of myocardial enhancement on two-phase MDCT images were compared with infarcted myocardial territories determined by using electrocardiogram, echocardiography, thallium-201 single photon emission computed tomography, catheter and MDCT coronary angiography. RESULTS: After clinical assessment, the presence of myocardial infarctions were found in 27 territories (19 AMI and 8 CMI) of 23 patients. Early perfusion defects were observed in 30 territories of all 23 patients. Three territories not corresponding to a myocardial infarction were detected in three patients with AMI and were associated with artifacts. Fourteen of perfusion defects were in the left anterior descending artery territory, four in the left circumflex artery territory, and nine in the right coronary artery territory. Delayed enhancement was observed in 25 territories (17 AMI and 8 CMI) of 21 patients. Delayed enhancement patterns were variable. Transmural early perfusion defects (n =12) were closely associated with transmural late enhancement (n = 5) and subendocardial residual defect with subepicardial late enhancement (n = 5). CONCLUSION: Myocardial infarction showed early perfusion defects and variable delayed enhancement patterns on two-phase contrast-enhanced MDCT. Delayed enhancement technique of MDCT could provide additional information of the location and extent of infarcted myocardium, and could be useful to plan appropriate therapeutic strategies in patients with AMI.
Adult ; Aged ; Aged, 80 and over ; Contrast Media ; Coronary Angiography ; Echocardiography ; Electrocardiography ; Female ; Humans ; Iohexol/analogs & derivatives/diagnostic use ; Male ; Middle Aged ; Myocardial Infarction/*radiography ; Tomography, Emission-Computed, Single-Photon ; Tomography, X-Ray Computed/*methods

OBJECTIVE: This study was designed to determine the optimal mixture ratio of gadolinium and iodinated contrast agent for simultaneous direct MR arthrography and CT arthrography. MATERIALS AND METHODS: An in vitro study was performed utilizing mixtures of gadolinium at six different concentrations (0.625, 1.25, 2.5, 5.0, 10 and 20 mmol/L) and iodinated contrast agent at seven different concentrations (0, 12.5, 25, 37.5, 50, 75 and 92-99.9%). These mixtures were placed in tissue culture plates, and were then imaged with CT and MR (with T1-weighted sequences, proton-density sequences and T2-weighted sequences). CT numbers and signal intensities were measured. Pearson's correlation coefficients were used to assess the correlations between the gadolinium/iodinated contrast agent mixtures and the CT numbers/MR signal intensities. Scatter diagrams were plotted for all gadolinium/iodinated contrast agent combinations and two radiologists in consensus identified the mixtures that yielded the optimal CT numbers and MR signal intensities. RESULTS: The CT numbers showed significant correlation with iodinated contrast concentrations (r = 0.976, p < 0.001), whereas the signal intensities as measured on MR images showed a significant correlation with both gadolinium and iodinated contrast agent concentrations (r = -484 to -0.719, p < 0.001). A review of the CT and MR images, graphs, and scatter diagram of 42 combinations of the contrast agent showed that a concentration of 1.25 mmol/L gadolinium and 25% iodinated contrast agent was the best combination for simultaneous CT and MR imaging. CONCLUSION: A mixture of 1.25 mmol/L gadolinium and 25% iodinated contrast agent was found to be optimal for simultaneous direct MR arthrography and CT arthrography.
*Arthrography ; Contrast Media/*administration & dosage ; Gadolinium/administration & dosage/*diagnostic use ; Iohexol/administration & dosage/*analogs & derivatives/diagnostic use ; *Magnetic Resonance Imaging ; Meglumine/administration & dosage/*diagnostic use ; Organometallic Compounds/administration & dosage/*diagnostic use ; Phantoms, Imaging ; *Tomography, X-Ray Computed