Diagnostic Value of 64-Slice Dual-Source CT Coronary Angiography in Patients with Atrial Fibrillation: Comparison with Invasive Coronary Angiography

Objective

We wanted to evaluate the image quality and diagnostic value of 64-slice dual-source computed tomography (DSCT) coronary angiography in patients with atrial fibrillation (Afib).

Materials and Methods

The coronary arteries of 22 Afib patients seen on DSCT were classified into 15 segments and the imaging quality (excellent, good, moderate and poor) and significant stenoses (≥ 50%) were evaluated by two radiologists who were blinded to the conventional coronary angiography (CAG) results. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) for detecting important coronary artery stenosis were calculated. McNemar test was used to determine any significant difference between DSCT and CAG, and Cohen''s Kappa statistics were calculated for the intermodality and interobserver agreement.

Results

The mean heart rate was 89 ± 8.3 bpm (range: 80-118 bpm). A range from 250 msec to 300 msec within the RR interval was the optimal reconstruction interval for the patients with Afib. The respective overall sensitivity, specificity, PPV and NPV values were 74%, 97%, 81% and 96% for reader 1 and 72%, 98%, 85% and 96% for reader 2. No significant difference between DSCT and CAG was found for detecting a significant stenosis (reader 1, p = 1.0; reader 2, p = 0.727). Cohen''s Kappa statistics demonstrated good intermodality and interobserver agreement.

Conclusion

64-slice DSCT coronary angiography provides good image quality in patients with atrial fibrillation without the need for controlling the heart rate. DSCT can be used for ruling out significant stenosis in patients with atrial fibrillation with its high NPV for detecting in important stenosis.     

Effect of Heart Rate and Coronary Calcification on the Diagnostic Accuracy of the Dual-Source CT Coronary Angiography in Patients with Suspected Coronary Artery Disease

Objective

To evaluate the diagnostic accuracy of a dual-source computed tomography (DSCT) coronary angiography, with a particular focus on the effect of heart rate and calcifications.

Materials and Methods

One hundred and nine patients with suspected coronary disease were divided into 2 groups according to a mean heart rate (< 70 bpm and ≥ 70 bpm) and into 3 groups according to the mean Agatston calcium scores (≤ 100, 101-400, and > 400). Next, the effect of heart rate and calcification on the accuracy of coronary artery stenosis detection was analyzed by using an invasive coronary angiography as a reference standard. Coronary segments of less than 1.5 mm in diameter in an American Heart Association (AHA) 15-segment model were independently assessed.

Results

The mean heart rate during the scan was 71.8 bpm, whereas the mean Agatston score was 226.5. Of the 1,588 segments examined, 1,533 (97%) were assessable. A total of 17 patients had calcium scores above 400 Agatston U, whereas 50 had heart rates ≥ 70 bpm. Overall the sensitivity, specificity, positive predictive values (PPV) and negative predictive values (NPV) for significant stenoses were: 95%, 91%, 65%, and 99% (by segment), respectively and 97%, 90%, 81%, and 91% (by artery), respectively (n = 475). Heart rate showed no significant impact on lesion detection; however, vessel calcification did show a significant impact on accuracy of assessment for coronary segments. The specificity, PPV and accuracy were 96%, 80%, and 96% (by segment), respectively for an Agatston score less than 100% and 99%, 96% and 98% (by artery). For an Agatston score of greater to or equal to 400 the specificity, PPV and accuracy were reduced to 79%, 55%, and 83% (by segment), respectively and to 79%, 69%, and 85% (by artery), respectively.

Conclusion

The DSCT provides a high rate of accuracy for the detection of significant coronary artery disease, even in patients with high heart rates and evidence of coronary calcification. However, patients with severe coronary calcification (> 400 U) remain a challenge to diagnose.     

Prospectively Electrocardiogram-Gated High-Pitch Spiral Acquisition Mode Dual-Source CT Coronary Angiography in Patients with High Heart Rates: Comparison with Retrospective Electrocardiogram-Gated Spiral Acquisition Mode

Objective

To assess the image quality and effective radiation dose of prospectively electrocardiogram (ECG)-gated high-pitch spiral acquisition mode (flash mode) of dual-source CT (DSCT) coronary angiography (CTCA) in patients with high heart rates (HRs) as compared with retrospectively ECG-gated spiral acquisition mode.

Materials and Methods

Two hundred and sixty-eight consecutive patients (132 female, mean age: 55 ± 11 years) with mean HR > 65 beats per minute (bpm) were prospectively included in this study. The patients were divided into two groups. Collection was performed in group A CTCA using flash mode setting at 20-30% of the R-R interval, and retrospectively ECG-gated spiral acquisition mode in group B. The image noise, contrast-to-noise ratio (CNR), image quality scores, effective radiation dose and influencing factors on image quality between the two groups were assessed.

Results

There were no significant differences in image quality scores and proportions of non-diagnostic coronary artery segments between two groups (image quality scores: 1.064 ± 0.306 [group A] vs. 1.084 ± 0.327 [group B], p = 0.063; proportion of non-diagnostic coronary artery segments: segment-based analysis 1.52% (group A) vs. 1.74% (group B), p = 0.345; patient-based analysis 7.5% (group A) vs. 6.7% (group B), p = 0.812). The estimated radiation dose was 1.0 ± 0.16 mSv in group A and 7.1 ± 1.05 mSv in group B (p = 0.001).

Conclusion

In conclusion, in patients with HRs > 65 bpm without cardiac arrhythmia, the prospectively high-pitch spiral-acquisition mode with image-acquired timing set at 20-30% of the R-R interval provides a similar image quality and low rate of non-diagnostic coronary segments to the retrospectively ECG-gated low-pitch spiral acquisition mode, with significant reduction of radiation exposure.     

Coronary Artery Disease in Asymptomatic Young Adults: Its Prevalence According to Coronary Artery Disease Risk Stratification and the CT Characteristics

Objective

We aimed at evaluating the prevalence and CT characteristics of occult coronary artery disease (CAD) in young Korean adults under 40 years of age by performing coronary CT angiography (CCTA).

Materials and Methods

We retrospectively enrolled 112 consecutive asymptomatic subjects (90 men, mean age: 35.6 ± 3.7 years) who underwent CCTA as part of a general health evaluation. We classified the subjects into three National Cholesterol Education Program risk categories and we assessed the plaque characteristics on CCTA according to the number of involved vessels, the location and type of plaques and vascular remodeling.

Results

Twelve individuals had CAD (11%, 11 men). The prevalence of CAD was significantly higher in the subgroups with moderate (22%) or high (25%) risk than that in the low risk subgroup (5%) (p < 0.05). Nine patients had single-vessel disease and three patients had two-vessel disease. The most common location for plaque was the proximal left anterior descending coronary artery (60%). All the patients had non-significant stenosis and plaque, including the non-calcified (27%), mixed (47%) and calcified (27%) types. Positive vascular remodeling was identified in all the patients with non-calcified or mixed plaques.

Conclusion

The prevalence of occult CAD was not negligible in the asymptomatic young adults with moderate to high risk, and this suggests the importance of management and risk factor modification in this population. All the patients had non-significant stenosis, and one fourth of the plaques did not show calcification.     

Myocardial bridging as evaluated by 16 row MDCT

Purpose

The purpose of this study is to find out the prevalence, appearance and clinical symptoms of myocardial bridging (MB) by MDCT coronary angiography (CTA).

Materials and methods

A total of 280 (50 females) consecutive patients followed with coronary artery disease or postoperative stent and bypass control, underwent CTA performed by 16-MDCT scanner between January 2006 and April 2006. Short axis multiplanar reformatted images were evaluated. MBs were classified as complete and incomplete bridges with respect to continuity of the myocardium over the tunneled segment of left anterior descending artery (LAD) in interventricular groove and the cut-off value is 1.3 mm. Patients diagnosed with MB on CTA who had prior catheter angiography studies were re-evaluated for the presence of MB.

Results

One hundred and twenty MBs [98 (81.6%) on LAD, 2 (1.6%) on diagonal branch, 11 (9.1%) on obtuse marginal, 4 (3.3%) on right coronary artery, 5 (4.1%) on ramus intermedius artery] were detected in 108 (38.5%) patients. Eighty-five (70.8%) of bridged segments in 79 (28.2%) patients were complete and the rest [35 (29.2%) in 34 (12.1%) patients] were incomplete. In 12 patients two MBs (either on different arteries or on the same artery) were detected. The length of bridged segments in patients with complete and incomplete MBs varied between 4–50.9 mm (mean 18 mm) and 4–37.3 mm (mean 13.6 mm), respectively, and the depth of myocardium over the artery ranged between 1–6.4 mm (mean 2.3 mm) and 1–1.2 mm (mean 1 mm), respectively. Thirty (27.7%) out of 108 patients, in whom MB was detected on CTA, were found to have correlative catheter angiography studies, retrospectively and MB was detected only in 4 (13.3%) out of 30 patients.

Conclusion

MDCT coronary angiography is a non-invasive, efficient method in the diagnosis of MB avoiding the procedural risks that catheter angiography carries. MDCT coronary angiography allows direct visualization of the bridge itself and may thus give the opportunity to differentiate between complete and incomplete myocardial bridges.     

Effect of Heart Rate and Body Mass Index on the Interscan and Interobserver Variability of Coronary Artery Calcium Scoring at Prospective ECG-Triggered 64-Slice CT

Objective

To test the effects of heart rate, body mass index (BMI) and noise level on interscan and interobserver variability of coronary artery calcium (CAC) scoring on a prospective electrocardiogram (ECG)-triggered 64-slice CT.

Materials and Methods

One hundred and ten patients (76 patients with CAC) were scanned twice on prospective ECG-triggered scans. The scan parameters included 120 kV, 82 mAs, a 2.5 mm thickness, and an acquisition center at 45% of the RR interval. The interscan and interobserver variability on the CAC scores (Agatston, volume, and mass) was calculated. The factors affecting the variability were determined by plotting it against heart rate, BMI, and noise level (defined as the standard deviation: SD).

Results

The estimated effective dose was 1.5 ± 0.2 mSv. The mean heart rate was 63 ± 12 bpm (range, 44-101 bpm). The patient BMIs were 24.5 ± 4.5 kg/m² (range, 15.5-42.3 kg/m²). The mean and median interscan variabilities were 11% and 6%, respectively by volume, and 11% and 6%, respectively, by mass. Moreover, the mean and median of the algorithms were lower than the Agatston algorithm (16% and 9%, respectively). The mean and median interobserver variability was 10% and 4%, respectively (average of algorithms). The mean noise levels were 15 ± 4 Hounsfield unit (HU) (range, 8-25 HU). The interscan and interobserver variability was not correlated with heart rate, BMI, or noise level.

Conclusion

The interscan and interobserver variability of CAC on a prospective ECG-triggered 64-slice CT with high image quality and 45% of RR acquisition is not significantly affected by heart rate, BMI, or noise level. The volume or mass algorithms show reduced interscan variability compared to the Agatston scoring (p < 0.05).     

Abnormal Motion of the Interventricular Septum after Coronary Artery Bypass Graft Surgery: Comprehensive Evaluation with MR Imaging

Objective

To define the mechanism associated with abnormal septal motion (ASM) after coronary artery bypass graft surgery (CABG) using comprehensive MR imaging techniques.

Materials and Methods

Eighteen patients (mean age, 58 ± 12 years; 15 males) were studied with comprehensive MR imaging using rest/stress perfusion, rest cine, and delayed enhancement (DE)-MR techniques before and after CABG. Myocardial tagging was also performed following CABG. Septal wall motion was compared in the ASM and non-ASM groups. Preoperative and postoperative results with regard to septal wall motion in the ASM group were also compared. We then analyzed circumferential strain after CABG in both the septal and lateral walls in the ASM group.

Results

All patients had normal septal wall motion and perfusion without evidence of non-viable myocardium prior to surgery. Postoperatively, ASM at rest and/or stress state was documented in 10 patients (56%). However, all of these had normal rest/stress perfusion and DE findings at the septum. Septal wall motion after CABG in the ASM group was significantly lower than that in the non-ASM group (2.1±5.3 mm vs. 14.9±4.7 mm in the non-ASM group; p < 0.001). In the ASM group, the degree of septal wall motion showed a significant decrease after CABG (preoperative vs. postoperative = 15.8±4.5 mm vs. 2.1±5.3 mm; p = 0.007). In the ASM group after CABG, circumferential shortening of the septum was even larger than that of the lateral wall (-20.89±5.41 vs. -15.41±3.7, p < 0.05)

Conclusion

Abnormal septal motion might not be caused by ischemic insult. We suggest that ASM might occur due to an increase in anterior cardiac mobility after incision of the pericardium.     

The Diagnostic Accuracy, Image Quality and Radiation Dose of 64-Slice Dual-Source CT in Daily Practice: a Single Institution's Experience

Objective

We wanted to evaluate the image quality, diagnostic accuracy and radiation exposure of 64-slice dual-source CT (DSCT) coronary angiography according to the heart rate in symptomatic patients during daily clinical practice.

Materials and Methods

We performed a retrospective search for the DSCT coronary angiography reports of 729 consecutive symptomatic patients. For the 131 patients who underwent invasive coronary angiography, the image quality, the diagnostic performance (sensitivity, specificity, positive predictive value [PPV] and negative predictive value [NPV] for detecting significant stenosis ≥ 50% diameter) and the radiation exposure were evaluated. These values were compared between the groups with differing heart rates (HR): mean HR < 65 or ≥ 65 and HR variability (HRV) < 15 or ≥ 15.

Results

Among the 729 patients, the CT reports showed no stenosis or insignificant coronary artery stenosis in 72%, significant stenosis in 26% and non-diagnostic in 2%. For the 131 patients who underwent invasive coronary angiography, 95% of the patients and 97% of the segments were evaluable, and the overall per-patient/per-segment sensitivity, the perpatient/per-segment specificity, the per-patient/per-segment PPV and the per-patient/per-segment NPV were 100%/90%, 71%/98%, 95%/88% and 100%/97%, respectively. The image quality was better in the HR < 65 group than in the HR ≥ 65 group (p = 0.001), but there was no difference in diagnostic performance between the two groups. The mean effective radiation doses were lower in the HR < 65 or HRV < 15 group (p < 0.0001): 5.5 versus 6.7 mSv for the mean HR groups and 5.3 versus 9.3 mSv for the HRV groups.

Conclusion

Dual-source CT coronary angiography is a highly accurate modality in the clinical setting. Better image quality and a significant radiation reduction are being rendered in the lower HR group.     

Combined Fluoroscopy- and CT-Guided Transthoracic Needle Biopsy Using a C-Arm Cone-Beam CT System: Comparison with Fluoroscopy-Guided Biopsy

Objective

The aim of this study was to evaluate the usefulness of combined fluoroscopy- and CT-guided transthoracic needle biopsy (FC-TNB) using a cone beam CT system in comparison to fluoroscopy-guided TNB (F-TNB).

Materials and Methods

We retrospectively evaluated 74 FC-TNB cases (group A) and 97 F-TNB cases (group B) to compare their respective diagnostic accuracies according to the size and depth of the lesion, as well as complications, procedure time, and radiation dose.

Results

The sensitivity for malignancy and diagnostic accuracy for small (< 30 mm in size) and deep (≥ 50 mm in depth) lesions were higher in group A (91% and 94%, 92% and 94%) than in group B (73% and 81%, 84% and 88%), however not statistically significant (p > 0.05). Concerning lesions ≥ 30 mm in size and < 50 mm in depth, both groups displayed similar results (group A, 91% and 92%, 80% and 87%; group B, 90% and 92%, 86% and 90%). Pneumothorax occurred 26% of the time in group A and 14% for group B. The mean procedure time and patient skin dose were significantly higher in group A (13.6 ± 4.0 minutes, 157.1 ± 76.5 mGy) than in group B (9.0 ± 3.5 minutes, 21.9 ± 15.2 mGy) (p < 0.05).

Conclusion

Combined fluoroscopy- and CT-guided TNB allows the biopsy of small (< 30 mm) and deep lesions (≥ 50 mm) with high diagnostic accuracy and short procedure times, whereas F-TNB is still a useful method for large and superficial lesions with a low radiation dose.     

Evaluation of Tracheobronchial Diseases: Comparison of Different Imaging Techniques

Objective

To compare the clinical utility of the different imaging techniques used for the evaluation of tracheobronchial diseases.

Materials and Methods

Forty-one patients with tracheobronchial diseases [tuberculosis (n = 18), bronchogenic carcinoma (n = 10), congenital abnormality (n = 3), post-operative stenosis (n = 2), and others (n = 8)] underwent chest radiography and spiral CT. Two sets of scan data were obtained: one from routine thick-section axial images and the other from thin-section axial images. Multiplanar reconstruction (MPR) and shaded surface display (SSD) images were obtained from thin-section data. Applying a 5-point scale, two observers compared chest radiography, routine CT, thin-section spiral CT, MPR and SSD imaging with regard to the detection, localization, extent, and characterization of a lesion, information on its relationship with adjacent structures, and overall information.

Results

SSD images were the most informative with regard to the detection (3.95±0.31), localization (3.95±0.22) and extent of a lesion (3.85±0.42), and overall information (3.83±0.44), while thin-section spiral CT scans provided most information regarding its relationship with adjacent structures (3.56±0.50) and characterization of the lesion (3.51±0.61).

Conclusion

SSD images and thin-section spiral CT scans can provide valuable information for the evaluation of tracheobronchial disease.     

Diagnosing Small Hepatic Cysts on Multidetector CT: an Additional Merit of Thinner Coronal Reformations

Objective

We wanted to validate the additional merit of the thinner coronal reformation images from multidetector CT (MDCT) for making the diagnosis of hepatic cysts.

Materials and Methods

For the 90 benign hepatic cysts confirmed on MRI, the transverse (5-mm thickness) and additional coronal (2-mm thickness) reformation images from MDCT were compared with each other in terms of the Hounsfield units (HUs) and the size of each hepatic cyst.

Results

The attenuations (mean: 17.2 HUs, standard deviation: ± 14.4) on the thinner coronal images were significantly lower than those (mean: 40.7 HUs; standard deviation: ± 20.6) on the thicker transverse images for the small hepatic cysts (≤ 10 mm on the transverse image, p < 0.01). Twenty-three (79%) of the 29 cysts between 5 mm and 10 mm and 21 (51%) of 41 lesions up to 5 mm showed a mean HU value of 20 or less on the coronal reformation images.

Conclusion

By reducing the partial volume effect, routine coronal reformation of MDCT with a thinner section thickness can provide another merit for making a confidential diagnosis of many small sub-centimeter hepatic cysts, and these small cysts are not easily characterized on the conventional transverse images.     

Detection of Small Hypervascular Hepatocellular Carcinomas in Cirrhotic Patients: Comparison of Superparamagnetic Iron Oxide-Enhanced MR Imaging with Dual-Phase Spiral CT

Objective

To compare the performance of superparamagnetic iron oxide (SPIO)-enhanced magnetic resonance (MR) imaging at 1.5T and dual-phase spiral computed tomography (CT) for the depiction of small hypervascular hepatocellular carcinomas (HCCs).

Materials and Methods

Forty-three patients with 70 small nodular HCCs (5-20 mm; mean, 13.7 mm) were examined. Diagnosis was based on the results of surgical biopsy in 22 patients and by the combined assessment of MR imaging, lipiodol CT, alpha feto-protein levels, and angiographic findings in 21. MR imaging consisted of respiratory-triggered turbo spin-echo T2-weighted imaging, T1-weighted fast low-angle shot, and T2*-weighted fast imaging with steady-state precession imaging before and after SPIO enhancement. CT imaging was performed with 5-mm collimation and 1:1.4 pitch, and began 30 and 65 secs after the injection of 150 mL of contrast medium at a rate of 3 mL/sec. Two blinded observers reviewed all images independently on a segment-by-segment basis. Diagnostic accuracy was evaluated using receiver operating characteristics (ROC) analysis.

Results

The mean areas (Az) under the ROC curves were 0.85 for SPIO-enhanced MR imaging and 0.79 for dual-phase spiral CT (p < .05). The mean sensitivity of SPIO-enhanced MR imaging was significantly higher than that of CT (p < .05), i.e. 70.6% for MR imaging and 58.1% for CT. MR imaging had higher false-positive rates than dual-phase spiral CT, but the difference was not statistically significant (3.7% vs 3.3%) (p > .05).

Conclusion

SPIO-enhanced MR imaging is more sensitive than dual-phase spiral CT for the depiction of small hypervascular hepatocellular carcinomas.     

Evaluation of Anterior Ethmoidal Artery by 320-Slice CT Angiography with Comparison to Three-Dimensional Spin Digital Subtraction Angiography: Initial Experiences

Objective

To explore the usefulness of 320-slice CT angiography (CTA) for evaluating the course of the anterior ethmoidal artery (AEA) and its relationship with adjacent structures by using three-dimensional (3D) spin digital subtraction angiography (DSA) as standard reference.

Materials and Methods

From December 2008 to December 2010, 32 patients with cerebrovascular disease, who underwent both cranial 3D spin DSA and 320-slice CTA within a 30 day period from each other, were retrospectively reviewed. AEA course in ethmoid was analyzed in DSA and CTA. In addition, adjacent bony landmarks (bony notch in medial orbital wall, anterior ethmoidal canal, and anterior ethmoidal sulcus) were evaluated with CTA using the MPR technique oriented along the axial, coronal and oblique coronal planes in all patients. The dose length product (DLP) for CTA and the dose-area product (DAP) for 3D spin DSA were recorded. Effective dose (ED) was calculated.

Results

The entire course of the AEA was seen in all 32 cases (100%) with 3D spine DSA and in 29 of 32 cases (90.1%) with 320-slice CTA, with no significant difference (p = 0.24). In three cases where AEA was not visualized on 320-slice CTA, two were due to the dominant posterior ethmoidal artery, while the remaining case was due to diminutive AEA. On MPR images of 320-slice CT, a bony notch in the orbital medial walls was detected in all cases (100%, 64 of 64); anterior ethmoidal canal was seen in 28 of 64 cases (43.8%), and the anterior ethmoidal sulcus was seen in 63 of 64 cases (98.4%). The mean effective dose in CTA was 0.6 ± 0.25 mSv, which was significantly lower than for 3D spin DSA (1.3 ± 0.01 mSv) (p < 0.001).

Conclusion

320-slice CTA has a similar detection rate for AEA to that of 3D spin DSA; however, it is noninvasive, and may be preferentially used for the evaluation of AEA and its adjacent bony variations and pathologic changes in preoperative patients with paranasal sinus diseases.     

High-Definition Computed Tomography for Coronary Artery Stent Imaging: a Phantom Study

Objective

To assess the performance of a high-definition CT (HDCT) for imaging small caliber coronary stents (≤ 3 mm) by comparing different scan modes of a conventional 64-row standard-definition CT (SDCT).

Materials and Methods

A cardiac phantom with twelve stents (2.5 mm and 3.0 mm in diameter) was scanned by HDCT and SDCT. The scan modes were retrospective electrocardiography (ECG)-gated helical and prospective ECG-triggered axial with tube voltages of 120 kVp and 100 kVp, respectively. The inner stent diameters (ISD) and the in-stent attenuation value (AV_in-stent) and the in-vessel extra-stent attenuation value (AV_in-vessel) were measured by two observers. The artificial lumen narrowing (ALN = [ISD - ISD_measured]/ISD) and artificial attenuation increase between in-stent and in-vessel (AAI = AV_in-stent - AV_in-vessel) were calculated. All data was analyzed by intraclass correlation and ANOVA-test.

Results

The correlation coefficient of ISD, AV_in-vessel and AV_in-stent between the two observers was good. The ALNs of HDCT were statistically lower than that of SDCT (30 ± 5.7% versus 35 ± 5.4%, p < 0.05). HDCT had statistically lower AAI values than SDCT (15.7 ± 81.4 HU versus 71.4 ± 90.5 HU, p < 0.05). The prospective axial dataset demonstrated smaller ALN than the retrospective helical dataset on both HDCT and SDCT (p < 0.05). Additionally, there were no differences in ALN between the 120 kVp and 100 kVp tube voltages on HDCT (p = 0.05).

Conclusion

High-definition CT helps improve measurement accuracy for imaging coronary stents compared to SDCT. HDCT with 100 kVp and the prospective ECG-triggered axial technique, with a lower radiation dose than 120 kVp application, may be advantageous in evaluating coronary stents with smaller calibers (≤ 3 mm).     

Differentiation of Adrenal Adenoma and Nonadenoma in Unenhanced CT: New Optimal Threshold Value and the Usefulness of Size Criteria for Differentiation

Objective

To determine the optimal threshold for the attenuation values in unenhanced computed tomography (CT) and assess the value of the size criteria for differentiating between an adrenal adenoma and a nonadenoma.

Materials and Methods

The unenhanced CT images of 45 patients at our institution, who underwent a surgical resection of an adrenal masses between January 2001 and July 2005, were retrospectively reviewed. Forty-five adrenal masses included 25 cortical adenomas, 12 pheochromocytomas, three lymphomas, and five metastases confirmed by pathology were examined. The CT images were obtained at a slice thickness of 2 mm to 3 mm. The mAs were varied from 100 to 160 and 200 to 280, while the 120 KVp was maintained in all cases. The mean attenuation values of an adrenal adenoma and nonadenoma were compared using an unpaired t test. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy at thresholds of 10 HU, 20 HU, and 25 HU were compared. The diagnostic accuracy according to the size criteria from 2 cm to 6 cm was also compared.

Results

The twenty-five adenomas showed significantly lower (p < 0.05) attenuation values(mean ± SD; 16.3 ± 14.9) than the nonadenomas (38.1 ± 6.8). Nineteen (90%) of the 20 nonadenomas had attenuation values ranging from 30 to 50 HU. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy for diagnosing adenomas were 36%, 100%, 100%, 56%, and 64%, respectively, at a threshold of 10 HU; 60%, 100%, 100%, 67%, and 78%, respectively, at a threshold of 20 HU; and 72%, 95%, 95%, 73%, and 82%, respectively, at a threshold of 25 HU. The adenomas had a significantly (p < 0.05) smaller diameter (2.44 ± 1.24 cm) than the nonadenomas (5.09 ± 2.37 cm). The size criteria using a diameter of 4-6 cm showed a sensitivity > 90% but a specificity < 70%. Size criteria of 2 or 3 cm had a high specificity of 100% and 80% but a low sensitivity of 20% and 60%.

Conclusion

The threshold attenuation values of 20 or 25 HU in the unenhanced CT appear optimal for discriminating an adrenal adenoma from a nonadenoma. The size criteria are of little value in differentiating adrenal masses because of their low specificity or low sensitivity.     

Spectral CT: Preliminary Studies in the Liver Cirrhosis

Objective

To investigate the value of spectral CT imaging in the diagnosis and classification of liver cirrhosis during the arterial phase (AP) and portal venous phase (PVP).

Materials and Methods

Thirty-eight patients with liver cirrhosis (Child-Pugh class A/B/C: n = 10/14/14), and 43 patients with healthy livers, participated in this study. The researchers used abdominal spectral CT imaging during AP and PVP. Iodine concentration, derived from the iodine-based material-decomposition image and the iodine concentration ratio (IC_ratio) between AP and PVP, were obtained. Statistical analyses {two-sample t test, One-factor analysis of variance, and area under the receiver operating characteristic curve (A [z])} were performed.

Results

The mean normalized iodine concentration (NIC) (0.5 ± 0.12) during PVP in the control group was significantly higher than that in the study group (0.4 ± 0.10 on average, 0.4 ± 0.08 for Class A, 0.4 ± 0.15 for Class B, and 0.4 ± 0.06 for Class C) (All p < 0.05). Within the cirrhotic liver group, the mean NIC for Class C during the AP (0.1 ± 0.05) was significantly higher than NICs for Classes A (0.1 ± 0.06) and B (0.1 ± 0.03) (Both p < 0.05). The IC_ratio in the study group (0.4 ± 0.15), especially for Class C (0.5 ± 0.14), was higher than that in the control group (0.3 ± 0.15) (p < 0.05).The combination of NIC and IC_ratio showed high sensitivity and specificity for differentiating healthy liver from cirrhotic liver, especially in Class C cirrhotic liver.

Conclusion

Spectral CT Provides a quantitative method with which to analyze the cirrhotic liver, and shows the potential value in the classification of liver cirrhosis.     

Coronary artery fistula in adults: evaluation with dual-source CT coronary angiography

Objective:

To evaluate the clinical value of dual-source CT (DSCT) coronary angiography in the diagnosis of coronary artery fistula (CAF) in adults.

Methods:

A large cohort of 17,548 patients, who underwent DSCT coronary angiography in our hospital between January 2008 and October 2013, were retrospectively reviewed for CAF. The origin, course and drainage site of CAF and coexisting abnormalities were analysed. The conventional angiography results, treatments and follow-up DSCT images were also evaluated.

Results:

A total of 33 CAFs from 17,548 patients were detected. The incidence of CAF was 0.19% by DSCT. CAF originating from the left coronary artery (LCA) was found in 14 (42.4%) patients, from right coronary artery (RCA) in 4 (12.1%) cases and from both LCA and RCA in 15 (45.5%) patients. The pulmonary artery was the most common site of drainage (28/33, 84.8%). 8 of the 33 (24.2%) cases were associated with aneurysms. Six cases were associated with coronary artery atherosclerosis. Four patients underwent conventional angiography.

Conclusion:

Coronary–pulmonary artery fistula in adults was found more often than in previous studies. CAF commonly originates from LCA or both LCA and RCA in adults. DSCT is a robust tool for investigating the origin, course and drainage site of CAF and coexistent abnormalities.

Advances in knowledge:

A large adult patient cohort who underwent DSCT angiography was reviewed to assess CAFs. Coronary–pulmonary artery fistula in adults was found more often than in previous studies. CAF was observed to originate from the LCA or both coronary arteries in adults. DSCT could clearly depict the fistula origin, course, drainage site and coexisting abnormalities. Conventional angiography results, treatments and follow-up DSCT images were analysed.Coronary artery fistulas (CAFs) are anomalous connections of the coronary arteries. The phenomenon was first described in 1865 by Krause.¹ CAF is considered as a major coronary anomaly by Ogden''s classification.² Most CAFs are congenital. CAFs have an estimated prevalence of 0.002% in the general population; however, they are present in 0.05–0.25% of patients who undergo coronary angiography.^3–5 The traditional diagnosis tool for CAFs is conventional angiography. With the advent of 64-slice multidetector CT in chest and cardiac imaging, the number of incidentally found CAFs has been increasing. The advanced electrocardiogram (ECG)-gated technique of dual-source CT (DSCT) could provide high diagnostic accuracy for the assessment of coronary artery disease.According to prior studies, CAF arises from the right coronary artery (RCA) in approximately 50% of patients.^6–8 In particular, 70% of the CAFs in children (mean age, 2.9 years) originated from the RCA.⁹ In this study, we focused on adult patients. A large cohort of adult patients who underwent DSCT angiography was reviewed to assess CAFs. The CAFs and coexisting abnormalities were analysed.     

Effects of Propranolol on the Left Ventricular Volume of Normal Subjects During CT Coronary Angiography

Objective

The purpose of this study is to determine the effects of propranolol on the left ventricular (LV) volume during CT coronary angiography.

Materials and Methods

The LV volume of 252 normal Chinese subjects (126 subjects with propranolol medication and 126 age- and gender-matched Chinese subjects without medication) was estimated using 64 slices multi-detector CT (MDCT). The heart rate difference was analyzed by the logistic linear regression model with variables that included gender, age, body height, body weight, systolic blood pressure (SBP), diastolic blood pressure (DBP) and the dosage of propranolol. The following global LV functional parameters were calculated: the real-end diastolic volume (EDV), the real-end systolic volume (ESV) and the real-ejection fraction (EF).

Results

The female subjects had a greater decrease of heart rate after taking propranolol. The difference of heart rate was negatively correlated with the dosage of propranolol. The real-EDV, the real-ESV and the real-EF ranged from 48.1 to 109 mL/m², 6.1 to 57.1 mL/m² and 41% to 88%, respectively. There was no significant difference in the SBP and DBP between the groups without and with propranolol medication (123 ± 17 and 80 ± 10 mmHg; 120 ± 14 and 80 ± 11 mmHg, respectively). The real-EDV showed no significant difference between these two groups, but the real-ESV and real-EF showed significant differences between these two groups (69.4 ± 9.3 and 70.6 ± 8.9 mL/m²; 23.5 ± 5.7 and 25.6 ± 3.7 mL/m², 66.5 ± 5.1% and 63.5 ± 4.6%, respectively).

Conclusion

The difference of heart rate is significantly influenced by gender and the dosage of propranolol. Propranolol will also increase the ESV, which contributes to a decreased EF, while the SBP, DBP and EDV are not statistically changed.     

Simple Pulmonary Eosinophilia Evaluated by Means of FDG PET: the Findings of 14 Cases

Objective

We wanted to describe the findings of simple pulmonary eosinophilia with using 18 fluorodeoxyglucose (FDG) positron emission tomography (PET).

Materials and Methods

We analysed the findings of 14 patients who underwent thoracic computed tomography (CT) and PET, and then they were subsequently proven to have simple pulmonary eosinophilia. PET studies were performed in four patients with malignancy to evaluate for cancer metastasis, and PET scans were also done in 10 healthy subjects who underwent volunteer cancer screening. The PET scans were evaluated by using the maximum standardized uptake values (SUVs). The subjects'' CT findings also were reviewed and correlated with the PET findings.

Results

A total of 42 nodules were detected on the CT scans. There were single nodules in three patients and multiple nodules in 11 patients (mean number of nodules: 3, range: 1-10, mean diameter: 9.5 mm ± 4.7). Twelve of 42 (28.6%) nodules showed FDG uptake and their mean maximum SUV was 2.5 ± 1.6 (range: 0.6-5.3). Five of six solid nodules showed FDG uptake (2.2 ± 1.1, range: 0.9-3.6), six of 11 semisolid nodules showed FDG uptake (3.1 ± 1.8, range: 0.6-5.3) and one of 25 pure ground-glass opacity nodule showed a maximum SUV of 0.8. The maximum SUVs of seven nodules in five patients were greater than 2.5. The maximum SUVs were significantly different according to the nodule types (p < 0.001).

Conclusion

Simple pulmonary eosinophilia commonly causes an increase in FDG uptake. Therefore, correlation of the PET findings with the CT findings or the peripheral eosinophil counts can help physicians arrive at the correct diagnosis of simple pulmonary eosinophilia.     

Myocardial Blood Flow and Flow Reserve in Proximal and Mid-to-Distal Lesions of Left Anterior Descending Artery Measured By N-13 Ammonia PET/CT

Purpose

The purpose of this study is to compare the myocardial blood flow (MBF) and flow reserve (MFR) between proximal and mid-to-distal lesions of the left anterior descending artery (pLAD and mdLAD, respectively) using N-13 ammonia positron emission tomography/computed tomography (PET/CT).

Methods

Subjects were 11 patients (six men and five women, mean age 64.5 years) with known coronary artery disease (CAD) involving LAD studied by N-13 ammonia PET/CT. They were divided into two groups by the location of stenotic lesions, i.e. pLAD versus mdLAD. Global and regional MBF and MFR were measured and compared. Characteristics of perfusion defects including the number of involved segments, basal area involvement, location, size, and shape were also compared between the two groups.

Results

The regional MFR in mid-anterior segment was significantly lower in pLAD group (1.80 ± 0.35 vs 2.76 ± 1.13 for pLAD and mdLAD groups, respectively, p = 0.034), while global MFR was not different (2.10 ± 1.10 vs 2.34 ± 0.84). Both stress and rest MBF in LAD territories were not different in both groups. The size of the perfusion defects were significantly larger in pLAD group (44.0 ± 11.5 % vs 21.1 ± 15.8 %, p = 0.041). Other characteristics such as location, basal area involvement, and shape were not significantly different between two groups.

Conclusions

The proximal lesion makes lower MFR in the mid-anterior segment and larger perfusion defect in the LAD territory but comparable MBF compared with mdLAD lesion.

Electronic supplementary material

The online version of this article (doi:10.1007/s13139-013-0208-6) contains supplementary material, which is available to authorized users.