MATERIALS AND METHODS. Of 222 patients with novel S-OIV (H1N1) infection seen from May 2009 to July 2009, 66 patients (30%) who underwent chest radiographs formed the study population. Group 1 patients (n = 14) required ICU admission and advanced mechanical ventilation, and group 2 (n = 52) did not. The initial radiographs were evaluated for the pattern (consolidation, ground-glass, nodules, and reticulation), distribution, and extent of abnormality. Chest CT scans (n = 15) were reviewed for the same findings and for pulmonary embolism (PE) when performed using IV contrast medium.

RESULTS. Group 1 patients were predominantly male with a higher mean age (43.5 years versus 22.1 years in group 2; p < 0.001). The initial radiograph was abnormal in 28 of 66 (42%) subjects. The predominant radiographic finding was patchy consolidation (14/28; 50%) most commonly in the lower (20/28; 71%) and central lung zones (20/28; 71%). All group 1 patients had abnormal initial radiographs; extensive disease involving ≥ 3 lung zones was seen in 93% (13/14) versus 9.6% (5/52) in group 2 (p < 0.001). No group 2 patients had > 20% overall lung involvement on initial radiographs compared with 93% of group 1 patients (13/14). PEs were seen on CT in 5/14 (36%) of group 1 patients.

CONCLUSION. Chest radiographs are normal in more than half of patients with S-OIV (H1N1) and progress to bilateral extensive air-space disease in severely ill patients, who are at a high risk for PE.

CONCLUSION. The most common radiographic and CT findings in seven patients with S-OIV infection are unilateral or bilateral ground-glass opacities with or without associated focal or multifocal areas of consolidation. On MDCT, the ground-glass opacities and areas of consolidation had a predominant peribronchovascular and subpleural distribution, resembling organizing pneumonia.

CONCLUSION. Radiography showed peripheral lung opacities. CT revealed peripheral ground-glass opacities suggesting peribronchial injury. These imaging findings raised suspicion of S-OIV despite negative H1N1 influenza rapid antigen test results from two nasopharyngeal swabs; subsequently, those results were proven to be false-negatives by reverse transcriptase polymerase chain reaction. This case suggests a role for CT in the early recognition of severe S-OIV.

CONCLUSION. Diseases of the thoracic lymphatic system have a wide variety of unique radiographic manifestations, all of which can be explained by the underlying pathophysiology and relationship to the normal distribution of lymphatics in the chest.

MATERIALS AND METHODS. Two reviewers were blinded to the patient groups and evaluated images of 15 coronary artery segments for each patient using 320-MDCT. The images were printed on glossy paper and scored subjectively as 1 or 2, meaning of diagnostic quality, or 3, meaning poor quality.

RESULTS. No statistical difference between the groups was noted in patient age: The mean age of the patients with atrial fibrillation was 67 years (age range, 52–82 years) and that of the patients in sinus rhythm was 59 years (36–86 years) (p = 0.3). Scores of 1 and 2 (diagnostic quality) were assigned to 100% in sinus rhythm and 96% in atrial fibrillation (p < 0.05). Scores of 3 were seen only in the atrial fibrillation group (7/175, 4%). Segment 15, the distal circumflex artery, was the segment that was most frequently assigned a score of 3 (2/7, 28.6%). A discrepancy in the two reviewers' scores was seen in 25 segments (7%), requiring joint consensus. The segments that most frequently required consensus reading were segments 12 and 15. The overall mean image quality score for all three coronary arteries in atrial fibrillation was 1.25 ± 0.47 (SD) and 1.08 ± 0.26 in sinus rhythm (p < 0.001). The median effective dose was 19.28 and 13.55 mSv in the atrial fibrillation and sinus rhythm groups, respectively.

CONCLUSION. The analysis of our initial experience shows that imaging in patients with atrial fibrillation is possible using 320-MDCT, with images of most segments obtained being of diagnostic quality. Segment 15 was the most difficult to see on 320-MDCT because of the small caliber of the vessel; poor visualization of that segment mostly occurred in the setting of a dominant right coronary arterial system.

SUBJECTS AND METHODS. The cases of 28 children with ASD initially diagnosed with TTE who were scheduled for cardiac CT for evaluation for insertion of an Amplatzer septal occluder under TEE guidance were reviewed. The patients were divided into a group with small ASD (long axis < 1.5 cm) and a group with large ASD (long axis ≥ 1.5 cm). Measurements of the ASD obtained at TTE, cardiac CT, and TEE were compared. Kappa statistics were used to correlate the diagnostic value of cardiac CT assessed by two independent reviewers.

RESULTS. After cardiac CT, six patients were excluded from occluder implantation; therefore, 22 patients (seven boys, 15 girls; mean age, 4.95 years; range, 2–11 years) were included in the study. There were no significant differences in the ages and sexes of the patients in the two groups, but pulmonary-to-systemic blood flow ratio in the large-ASD group was significantly greater than that in the small-ASD group (3.54 ± 1.43 vs 1.89 ± 0.36; p = 0.001). With respect to long- and short-axis lengths of the ASD, interatrial septum, and four rims and to detection of rim deficiency, neither group had a significant difference between cardiac CT findings at ventricular end-systole and TEE findings. The long axis of the ASD in the large-ASD group measured at cardiac CT at end-systole and TEE was significantly longer than the long axis measured at TTE (p = 0.012). A high diagnostic score with good interobserver correlation ( = 0.674–0.750) validated the feasibility of cardiac CT in the assessment of ASD for closure with an Amplatzer septal occluder.

CONCLUSION. The long axis of a large ASD can be underestimated at TTE. Cardiac CT seems comparable with TEE in the assessment of ASD and is helpful in noninvasive evaluation for Amplatzer septal occluder implantation, especially for large ASD.

CONCLUSION. Coronary MDCTA has provided an opportunity for noninvasive evaluation of the coronary arteries in patients with HIES. These coronary abnormalities vary from tortuosity to ectatic dilation and focal aneurysms of the coronary arteries. Such an evaluation has potential value in identifying new aspects of this disease and thereby providing better understanding of the pathophysiology of the disorder.

MATERIALS AND METHODS. Patient characteristics, radiology report content, additional imaging performed, final diagnosis, and diagnostic adequacy were recorded for pregnant patients consecutively referred for lung scintigraphy or pulmonary CTA according to physician preference. Measurements of pulmonary arterial enhancement were performed on all pulmonary CTA images of pregnant patients. Lung scintigraphy and pulmonary CTA studies deemed inadequate for diagnosis at the time of image acquisition were further assessed, and the cause of diagnostic inadequacy was determined. The relative contribution of the inferior vena cava to the right side of the heart was measured on nondiagnostic CTA images and compared with that on CTA images of age-matched nonpregnant women, who were the controls.

RESULTS. Twenty-eight pulmonary CTA examinations were performed on 25 pregnant patients, and 25 lung scintigraphic studies were performed on 25 pregnant patients. Lung scintigraphy was more frequently adequate for diagnosis than was pulmonary CTA (4% vs 35.7%) (p = 0.0058). Pulmonary CTA had a higher diagnostic inadequacy rate among pregnant than nonpregnant women (35.7% vs 2.1%) (p < 0.001). Transient interruption of contrast material by unopacified blood from the inferior vena cava was identified in eight of 10 nondiagnostic pulmonary CTA studies.

CONCLUSION. We found that lung scintigraphy was more reliable than pulmonary CTA in pregnant patients. Transient interruption of contrast material by unopacified blood from the inferior vena cava is a common finding at pulmonary CTA of pregnant patients.

CONCLUSION. In this article, we summarize the basic concepts, protocols, and techniques that we use for CT-guided core biopsy of lung lesions to assist radiologists in obtaining diagnostic specimens while reducing preventable complications.

SUBJECTS AND METHODS. Patients with suspected myocardial scar were examined on a 1.5-T MR scanner for myocardial late enhancement after the administration of gadopentetate dimeglumine using a segmented 2D PSIR turbo FLASH sequence followed by a navigator-gated 3D PSIR turbo FLASH sequence. Image quality was scored by two independent readers using a 4-point Likert scale (0 = poor, nondiagnostic; 1 = fair, diagnostics may be impaired; 2 = good, some artifacts but not interfering in diagnostics; 3 = excellent, no artifacts). Scars were compared quantitatively in volume and graded qualitatively on the basis of size (area) and location.

RESULTS. Thirty-three patients were scanned using both techniques. In 25 patients, the quality of the 3D PSIR images was acceptable. Scars were detected in 12 patients. Hyperenhanced scar volumes (p = 0.43), qualitative analysis of scar area (p = 0.78), and scar location (p = 0.68) were similar for both techniques. More small hyperenhanced scars, corresponding mostly to nonischemic distribution patterns, were detected using 3D PSIR than 2D PSIR. Although 2D and 3D results were found to be highly correlated for scar volume, Bland-Altman analysis indicated a systematic smaller infarct volume on the 2D PSIR scans (R² = 0.84).

CONCLUSION. Free-breathing 3D PSIR turbo FLASH imaging is a promising technique for the assessment of left ventricular scar particularly for scar quantification and the detection of small nonischemic scars in the myocardium.

MATERIALS AND METHODS. Sixty-two patients with mechanical valves (37 single-disc, 27 bileaflet; 59 aortic, 5 mitral) were evaluated with ECG-gated 64-MDCT and transthoracic echocardiography; a subset of 10 patients underwent cinefluoroscopy. Two readers independently interpreted each study.

RESULTS. The mean age of the patients was 46.4 ± 14.4 years; 50 were men and 12 were women. There was excellent correlation, and differences between CT readers were absent to small in measuring the opening angle (r = 0.96, p < 0.001; 76.7 ± 9.0° vs 76.8 ± 9.6°, p = 0.73), annulus diameter (r = 0.96, p < 0.001; 25.9 ± 3.3 vs 25.9 ± 3.2 mm, p = 0.62), and geometric orifice area (r = 0.98, p < 0.001; 3.8 ± 0.9 vs 3.6 ± 0.8 cm², p < 0.001). There was strong correlation without difference in opening angle between CT and cinefluoroscopy (r = 0.77, p < 0.001; 79.2° ± 9.8° vs 77.2° ± 15.5°, p = 0.45). Compared with manufacturer specifications, CT reported opening angles that were smaller for single-disc valves (n = 36, 67.4° ± 5.7° vs 75°, p < 0.001) and similar for bileaflet valves (n = 42 for 21 valves, 83.8° ± 3.9° vs 85°, p = 0.05), valves, with small underestimation with CT versus specifications in annulus diameter (n = 41; r = 0.75, p < 0.001; 26.4 ± 3.0 vs 27.5 ± 3.3 mm, p = 0.003), and geometric orifice area (n = 35; r = 0.90, p < 0.001; 3.7 ± 0.7 vs 3.8 ± 0.8 cm², p = 0.04). Each disc closed fully on CT; none had more than mild regurgitation on echocardiography.

CONCLUSION. CT can measure the size and function of mechanical valves with high interobserver agreement and results similar to specifications. The opening angle with CT strongly correlates with cinefluoroscopy. CT is promising for the assessment of mechanical valves.

MATERIALS AND METHODS. We used 60 chest radiographs; 30 depicted solitary pulmonary nodules, and 30 showed no nodules. A stratified random-sampling scheme was used to select the images from the standard digital image database developed by the Japanese Society of Radiologic Technology. The mean diameter of the 30 pulmonary nodules was 14.7 ± 4.1 (SD) mm. Receiver operating characteristic analysis was used to evaluate observer performance in the detection of pulmonary nodules first on the chest radiographs without and then on the radiographs with rib suppression. Seven board-certified radiologists and five radiology residents participated in this observer study.

RESULTS. For all 12 observers, the mean values of the area under the best-fit receiver operating characteristic curve for images without and with rib suppression were 0.816 ± 0.077 and 0.843 ± 0.074; the difference was statistically significant (p = 0.019). The mean areas under the curve for images without and with rib suppression were 0.848 ± 0.059 and 0.883 ± 0.050 for the seven board-certified radiologists (p = 0.011) and 0.770 ± 0.081 and 0.788 ± 0.074 for the five radiology residents (p = 0.310).

CONCLUSION. In the detection of pulmonary nodules, evaluation of a combination of rib-suppressed and original chest radiographs significantly improved the diagnostic performance of radiologists over the use of chest radiographs alone.

SUBJECTS AND METHODS. Perfusion CT was performed on an MDCT scanner with 50 mL of iodinated contrast material injected at 4 mL/s. The quality of each functional map was rated from 0 to 3 for 123 patients with confirmed lung cancer. A subset of images was independently reviewed by two radiologists to measure interobserver and intraobserver variability. Perfusion parameters and tumor response were assessed for 35 patients with non–small cell lung cancer who underwent chemoradiation therapy. Progression-free survival and overall survival were analyzed for 22 patients who underwent repeated perfusion CT after therapy.

RESULTS. Image quality was graded 2 (moderate) or 3 (good) in 68.2% of cases. High interobserver and intraobserver correlations of perfusion parameters were found on qualified images. The patients who responded to chemoradiation therapy had significantly greater blood flow (p = 0.023) than patients who did not respond. The median progression-free survival period of the patients with an increased permeability–surface area product was 4.7 months, significantly lower than the median progression-free survival period of 19.0 months among patients with a decreased permeability–surface area product (p < 0.001). The median overall survival period was 10.6 months for the group with an increased permeability–surface area product, significantly lower than the 19.3 months for the group with a decreased permeability–surface area product (p = 0.004).

CONCLUSION. Non–small cell lung cancer with higher perfusion is more sensitive to chemoradiation therapy than that with lower perfusion. After chemoradiation therapy, findings at perfusion CT are a significant predictor of early tumor response and overall survival among patients with non–small cell lung cancer.

MATERIALS AND METHODS. Cardiac CT was performed in 35 patients with ACS: 24 patients with acute myocardial infarction (AMI) and 11 patients with unstable angina pectoris (UAP). We reconstructed 2D myocardial images at diastolic and systolic phases using the same raw data as those used for coronary CT angiography. The CT number in the myocardium was used as an estimate of ischemia. The myocardium was shown using a color scale that depicts faint low-density areas more clearly than gray scale. We evaluated the variations in myocardial enhancement during the cardiac cycle in the territory of the culprit lesion. In addition, we classified patients on the basis of the transmurality of myocardial enhancement and examined whether this feature correlates with myocardial damage.

RESULTS. Myocardial imaging at systole showed myocardial hypoenhancement in territories of the culprit lesion in 91% of patients with ACS, 96% of patients with AMI, and 75% of patients with UAP. The hypoenhancement areas at systole tended to be more extensive than those at diastole. The transmural extent of hypoenhancement at systole correlated with myocardial damage, which was shown by myocardial biomarkers.

CONCLUSION. CT myocardial imaging can be used to assess myocardial ischemia in the appropriate region of ACS with high sensitivity.

CONCLUSION. We propose a methodical diagnostic approach to determining the visceroatrial situs and cardiac configuration that predicts the probability and types of associated congenital heart disease.

CONCLUSION. The characteristic CT findings of hydrocarbon pneumonitis after diesel fuel siphonage are the presence of air–space consolidations with predominant right middle lobe involvement and areas of low attenuation within consolidation. Occasionally, bronchoalveolar lavage is needed to confirm the diagnosis of hydrocarbon pneumonitis by the presence of lipid-laden macrophages on the basis of a history of diesel fuel aspiration.

MATERIALS AND METHODS. Over a 4-year period, 36 patients with symptomatic pericardial effusion were treated with CT-guided percutaneous placement of an indwelling pericardial catheter, for a total of 39 CT-guided tube pericardiostomy procedures. Thirty-three patients (92%) had undergone major cardiothoracic surgery, and three patients (8%) had undergone minimally invasive procedures. The medical records were retrospectively reviewed for clinical presentation, surgical history, imaging studies performed, procedural details, fluid characterization, and outcome. Charge comparison was performed with the American Medical Association Current Procedural Terminology codes and information acquired from the billing department at our facility.

RESULTS. All 39 CT-guided tube pericardiostomy procedures were performed successfully without clinically significant complications. After 33 of the 39 procedures (85%), symptoms did not recur after the catheter was removed. Three of 36 patients (8%) had a recurrence of pericardial effusion. Comparison of procedure charges showed an 89% saving over intraoperative pericardial window procedures and no significant difference compared with ultrasound-guided tube pericardiostomy. Eight patients (21% of procedures) needed pleural drainage procedures, all of which were performed in the CT suite immediately after the tube pericardiostomy procedure.

CONCLUSION. CT-guided tube pericardiostomy is a safe and effective alternative to surgical drainage in the care of patients with clinically significant pericardial effusion after cardiothoracic surgery and has the additional benefit of substantial cost savings.

SUBJECTS AND METHODS. Thirty-seven patients underwent black-blood fat-suppressed T2-weighted, rest perfusion, and late gadolinium-enhanced MRI 5.4 ± 3.1 days after the onset of acute myocardial infarction. On T2-weighted MR images, the signal intensity in relation to that of remote myocardium was determined in the late gadolinium-enhanced and periinfarction areas. Segment-based analysis was performed to determine whether the presence of microvascular obstruction influences the detection of myocardial edema.

RESULTS. The averaged signal intensity in the late gadolinium-enhanced area without microvascular obstruction was significantly higher than the signal intensity in remote normal myocardium (relative signal intensity, 1.83 ± 0.50; p < 0.001). In contrast, the signal intensity in the microvascular obstruction area on T2-weighted images was not significantly different from the signal intensity in remote myocardium (relative signal intensity, 1.14 ± 0.26). The percentages of late gadolinium-enhanced segments with high signal intensity on T2-weighted MR images were 95% (73/77) without microvascular obstruction and 30% (22/73) with microvascular obstruction.

CONCLUSION. With T2-weighted MRI, infarction-associated edema can be reliably detected in infarct lesions without microvascular obstruction. Microvascular obstruction, however, does not necessarily exhibit high signal intensity on T2-weighted MRI. Careful attention is required in interpretation of cardiac MR images of patients who have experienced acute myocardial infarction and undergone percutaneous coronary intervention. The findings on T2-weighted MR images can be substantial underestimates of the extent of acute myocardial infarction.