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1.  Multidetector CT imaging of pleura: comparison of two contrast infusion protocols 
The British Journal of Radiology  2011;84(1005):796-799.
Objectives
Imaging of the pleura by multidetector CT (MDCT) can be challenging. There is no clear evidence or guidelines on contrast infusion parameters for imaging pleura. We compared two contrast protocols for assessing pleural pathology on MDCT.
Methods
This was a prospective study in which consecutive patients with MDCT for suspected pleural disease on chest radiograph were randomised into two groups. The first group received 150 ml of intravenous contrast at a rate of 2.5 ml s–1 and the second group received 100 ml at 2 ml s–1. Images were acquired after a 60 s delay. Hounsfield units of the pleura, thoracic aorta, main pulmonary artery, portal vein and superior mesenteric artery were measured and analysed by two independent readers.
Results
40 patients (20 in each group) who had pleural enhancement on MDCT were included for final analysis. The mean pleural enhancement value was 83 HU (Group A) vs 59 HU (Group B) (p = 0.0004). The mean aortic enhancement was 241 HU (A) vs 141 HU (B) (p<0.0001); main pulmonary artery enhancement was 208 HU (A) vs 139 HU (B) (p<0.0002); portal venous enhancement was 169 HU (A) vs 115 HU (B) (p<0.0001); and the superior mesenteric artery enhancement was 215 HU (A) vs 128 HU (B) (p<0.0001).
Conclusion
Enhancement of the pleura and major vessels was significantly higher in the group receiving more contrast at a greater infusion rate. This technique of a single scan through the entire pleural surface with a delayed acquisition is promising. When pleural disease is suspected, contrast infusion protocols should be modified to achieve the best results and clinicians should be encouraged to specifically request a “pleural CT”.
doi:10.1259/bjr/55980445
PMCID: PMC3473793  PMID: 21159803
2.  MRI versus 64-row MDCT for diagnosis of hepatocellular carcinoma 
AIM: To compare the diagnostic capability of multidetector computed tomography (MDCT) and magnetic resonance imaging (MRI) for the detection of hepatocellular carcinoma (HCC) tumour nodules and their effect on patient management.
METHODS: A total of 28 patients (25 male, 3 female, mean age 67 ± 10.8 years) with biopsy-proven HCC were investigated with 64-row MDCT (slice 3 mm native, arterial and portal-venous phase, 120 mL Iomeprol, 4 mL/s, delay by bolus trigger) and MRI (T1fs fl2d TE/TR 2.72/129 ms, T2tse TE/TR 102/4000 ms, 5-phase dynamic contrast-enhanced T1fs fl3d TE/TR 1.56/4.6, Gadolinium-DTPA, slice 4 mm). Consensus reading of both modalities was used as reference. Tumour nodules were analyzed with respect to number, size, and location.
RESULTS: In total, 162 tumour nodules were detected by consensus reading. MRI detected significantly more tumour nodules (159 vs 123, P < 0.001) compared to MDCT, with the best sensitivity for early arterial phase MRI. False-negative CT findings included nodules ≤ 5 mm ( n = 5), ≤ 10 mm ( n = 17), ≤ 15 mm ( n = 12 ), ≤ 20 mm ( n = 4 ), and 1 nodule > 20 mm. MRI missed 2 nodules ≤ 10 mm and 1 nodule ≤ 15 mm. On MRI, nodule diameters were greater than on CT (29.2 ± 25.1 mm, range 5-140 mm vs 24.1 ± 22.7 mm, range 4-129 mm, P < 0.005). In 2 patients, MDCT showed only unilobar tumour spread, whereas MRI revealed additional nodules in the contralateral lobe. Detection of these nodules could have changed the therapeutic strategy.
CONCLUSION: Contrast-enhanced MRI is superior to 64-row MDCT for the detection of HCC nodules. Patients should be allocated to interventional or operative treatment according to a dedicated MRI-protocol.
doi:10.3748/wjg.15.6044
PMCID: PMC2797660  PMID: 20027676
American Association for the Study of Liver Diseases; European Association for the Study of the Liver; Hepatocellular carcinoma; Multidetector computed tomography; Magnetic resonance imaging
3.  Detection of small (≤ 2 cm) pancreatic adenocarcinoma and surrounding parenchyma: correlations between enhancement patterns at triphasic MDCT and histologic features 
BMC Gastroenterology  2014;14:16.
Background
The aim is to assess the time-density curves (TDCs) and correlate the histologic results for small (≤ 2 cm) PDA and surrounding parenchyma at triphasic Multidetector-row CT (MDCT).
Methods
Triphasic MDCT scans of 38 consecutive patients who underwent surgery for a small PDA were retrospectively reviewed. The TDCs were analyzed and compared with histologic examination of the PDA and pancreas upstream/downstream in all cases. Three enhancement patterns were identified: 1) enhancement peak during pancreatic parenchymal phase (PPP) followed by a rapid decline on portal venous phase (PVP) and delayed phase (DP) at 5 minutes (type 1 pattern: normal pancreas); 2) maximum enhancement in PVP that gradually decreases in DP (type 2 pattern: mild chronic pancreatitis or PDA with mild fibrous stroma); 3) progressive enhancement with maximum peak in DP (type 3 pattern: severe chronic pancreatitis or PDA with severe fibrous stroma). A p value less than 0.05 was considered statistically significant. Sensitivity was calculated for PDA detection and an attenuation difference with the surrounding tissue of at least 10 HU was considered.
Results
PDA showed type 2 pattern in 5/38 cases (13.2%) and type 3 pattern in 33/38 cases (86,8%). Pancreas upstream to the tumor had type 2 pattern in 20/38 cases (52,6%) and type 3 pattern in 18/38 cases (47,4%). Pancreas downstream to the tumor had type 1 pattern in 19/25 cases (76%) and type 2 pattern in 6/25 cases (24%). Attenuation difference between tumor and parenchyma upstream was higher of 10 UH on PPP in 31/38 patients (sensitivity = 81.6%), on PVP in 29/38 (sensitivity = 76.3%) and on DP in 17/38 (sensitivity = 44.7%). Attenuation difference between tumor and parenchyma downstream was higher of 10 UH on PPP in 25/25 patients (sensitivity = 100%), on PVP in 22/25 (sensitivity = 88%) and on DP in 20/25 (sensitivity = 80%). Small PDAs were isodense to the pancreas upstream to the tumor, and therefore unrecognizable, in 8 cases (8/38; 21%) at qualitative analysis and in 4 cases (4/38; 10,5%) at quantitative analysis.
Conclusions
The quantitative analysis increases the sensitivity for detection of small PDA at triphasic MDCT.
doi:10.1186/1471-230X-14-16
PMCID: PMC3903041  PMID: 24447719
Pancreas; Pancreas; Neoplasms; Helical Computed Tomography (CT); Triphasic Helical CT; Quantitative analysis
4.  Optimising the scan delay for arterial phase imaging of the liver using the bolus tracking technique 
Objective:
To optimize the delay time before the initiation of arterial phase scan in the detection of focal liver lesions in contrast enhanced 5 phase liver CT using the bolus tracking technique.
Patients and Methods:
Delay - the interval between threshold enhancement of 100 hounsfield unit (HU) in the abdominal aorta and commencement of the first arterial phase scan. Using a 16 slice CT scanner, a plain CT of the liver was done followed by an intravenous bolus of 120 ml nonionic iodinated contrast media (370 mg I/ml) at the rate of 4 mL/s. The second phase scan started immediately after the first phase scan. The portal venous and delay phases were obtained at a fixed delay of 60 s and 90 s from the beginning of contrast injection. Contrast enhancement index (CEI) and subjective visual conspicuity scores for each lesion were compared among the three groups.
Results:
84 lesions (11 hepatocellular carcinomas, 17 hemangiomas, 39 other hypervascular lesions and 45 cysts) were evaluated. CEI for hepatocellular carcinomas appears to be higher during the first arterial phase in the 6 seconds delay group. No significant difference in CEI and mean conspicuity scores among the three groups for hemangioma, other hypervascular lesions and cysts.
Conclusion:
The conspicuity of hepatocellular carcinomas appeared better during the early arterial phase using a bolus tracking technique with a scan delay of 6 seconds from the 100 HU threshold in the abdominal aorta.
doi:10.2349/biij.7.2.e12
PMCID: PMC3265150  PMID: 22287986
Arterial phase imaging of the liver; bolus tracking technique
5.  Automatic Bolus Tracking Versus Fixed Time-Delay Technique in Biphasic Multidetector Computed Tomography of the Abdomen 
Iranian Journal of Radiology  2014;11(1):e4617.
Background
Bolus tracking can individualize time delay for the start of scans in spiral computed tomography (CT).
Objectives
We compared automatic bolus tracking method with fixed time-delay technique in biphasic contrast enhancement during multidetector CT of abdomen.
Patients and Methods
Adult patients referred for spiral CT of the abdomen were randomized into two groups; in group 1, the arterial and portal phases of spiral scans were started 25 s and 55 s after the start of contrast material administration; in group 2, using the automatic bolus tracking software, repetitive monitoring scans were performed within the lumen of the descending aorta as the region of interest with the threshold of starting the diagnostic scans as 60 HU. The contrast enhancement of the aorta, liver, and spleen were compared between the groups.
Results
Forty-eight patients (23 males, 25 females, mean age=56.4±13.5 years) were included. The contrast enhancement of the aorta, liver, and spleen at the arterial phase was similar between the two groups (P>0.05). Regarding the portal phase, the aorta and spleen were more enhanced in the bolus-tracking group (P<0.001). The bolus tracking provided more homogeneous contrast enhancement among different patients than the fixed time-delay technique in the liver at portal phase, but not at the arterial phase.
Conclusions
The automatic bolus-tracking method, results in higher contrast enhancement of the aorta and spleen at the portal phase, but has no effect on liver enhancement. However, bolus tracking is associated with reduced variability for liver enhancement among different patients.
doi:10.5812/iranjradiol.4617
PMCID: PMC3955856
Multidetector Computed Tomography; Tomography, Spiral Computed
6.  Enhancement patterns of hepatocellular carcinomas on multiphasic multidetector row CT: comparison with pathological differentiation 
The British Journal of Radiology  2012;85(1017):e573-e583.
Objective
The objective of this study was to determine the incidence of typical and atypical enhancement patterns of hepatocellular carcinomas (HCCs) on multiphasic multidetector row CT (MDCT) and to correlate the enhancement patterns and morphological image findings of HCC with the degree of tumour differentiation.
Methods
MDCT images of 217 patients with 243 surgically proven HCCs were evaluated through consensus reading by two radiologists. Our MDCT protocol was composed of precontrast, arterial, portal and delayed phases. The reviewers analysed the CT images for degree of attenuation; relative timing of washout; presence of dysmorphic intratumoral vessels, aneurysms and necrosis; tumour size; tumour margin; presence of pseudocapsule; intratumoral heterogeneity; and determined enhancement pattern. The imaging features were correlated with tumour differentiation using Fisher's exact test or the χ2 test.
Results
Among 243 HCCs, 137 (56.4%) showed the typical enhancement pattern of HCC, which is arterial enhancement and washout on portal or equilibrium phase images. In the arterial phase, 190 of 243 (78.2%) HCCs showed hypervascularity, with approximately three quarters of poorly differentiated (PD) (34 of 45, 75.6%) and moderately differentiated (MD) HCCs (92 of 123, 74.8%) showing washout during the portal or delayed phases, vs only 50% of well-differentiated (WD) HCCs (11 of 22; p<0.048). The presence of intratumoral vessels and aneurysms, tumour necrosis, attenuation of precontrast, the relative timing of washout, intratumoral attenuation heterogeneity, tumour margin and tumour size were correlated with the pathological differentiation of HCCs (p<0.05).
Conclusion
A typical enhancement of HCCs on MDCT was not unusual (43.6%) and WD and PD HCCs account for most of the atypical enhancement patterns. Early washout favoured MD and PD HCCs rather than WD HCCs, whereas in our study the presence of intratumoral aneurysm was a highly specific finding for PD HCC.
doi:10.1259/bjr/86767895
PMCID: PMC3487070  PMID: 22919011
7.  Evaluation of coronary atheroma by 64-slice multidetector computed tomography: Comparison with intravascular ultrasound and angiography 
The Canadian Journal of Cardiology  2009;25(11):641-647.
BACKGROUND:
Recent improvements in multidetector computed tomography (MDCT) with 64-slice scanners have allowed acquisition of a coronary study in 5 s to 6 s, with good temporal and spatial resolution. Previous studies have reported an underestimation of plaque burden by MDCT. Whether shorter scan times can allow correct assessment of plaque volume requires comparison with intravascular ultrasound (IVUS).
METHODS:
Patients (n=30) scheduled for coronary angiography also underwent MDCT and IVUS examinations within 96 h. MDCT examination was performed with a 64-slice scanner. Nitroglycerin was administered before all imaging procedures. MDCT, quantitative coronary angiography (QCA) and IVUS analyses were performed by observers blinded to other results. Plaque volumes were determined by MDCT and IVUS in one vessel, and maximum percentage diameter stenosis was identified in each coronary segment by MDCT and QCA.
RESULTS:
The mean (± SD) plaque volume was determined to be 179.1±78.9 mm3 by MDCT and 176.1±87.9 mm3 by IVUS. There was a strong positive correlation for plaque volume between MDCT and IVUS (r=0.84, P<0.0001). Percentage diameter stenosis assessed by MDCT and QCA also correlated well (r=0.88 per patient and r=0.87 per vessel, P<0.0001 for both). The maximum percentage diameter stenosis per vessel was 38.1±30.2% with MDCT and 34.1±27.6% with QCA. The sensitivity and specificity of MDCT in detecting stenoses above 50% per vessel were 100% and 91.0%, respectively.
CONCLUSIONS:
Plaque volumes measured by 64-slice MDCT and IVUS correlate well, without systematic underestimation. The sensitivity and specificity of MDCT to detect stenoses greater than 50% by QCA are excellent with the administration of nitroglycerin before imaging.
PMCID: PMC2776562  PMID: 19898696
Angiography; Atherosclerosis; Coronary disease; Tomography; Ultrasonics
8.  Multidetector row CT for imaging the paediatric tracheobronchial tree 
Pediatric Radiology  2007;37(6):515-529.
The introduction of multidetector row computed tomography (MDCT) scanners has altered the approach to imaging the paediatric thorax. In an environment where the rapid acquisition of CT data allows general hospitals to image children instead of referring them to specialist paediatric centres, it is vital that general radiologists have access to protocols appropriate for paediatric applications. Thus a dramatic reduction in the delivered radiation dose is ensured with optimal contrast bolus delivery and timing, and inappropriate repetition of the scans is avoided. This article focuses on the main principles of volumetric CT imaging that apply generically to all MDCT scanners. We describe the reconstruction techniques for imaging the paediatric thorax and the low-dose protocols used in our institution on a 16-slice detector CT scanner. Examples of the commonest clinical applications are also given.
doi:10.1007/s00247-007-0434-0
PMCID: PMC1891645  PMID: 17457581
Volumetric; Multidetector CT; Tracheobronchial tree; Children
9.  Hepatocellular carcinoma in cirrhotic patients at multidetector CT: hepatic venous phase versus delayed phase for the detection of tumour washout 
The British Journal of Radiology  2011;84(1001):403-412.
Objectives
Our aim was to compare retrospectively hepatic venous and delayed phase images for the detection of tumour washout during multiphasic multidetector row CT (MDCT) of the liver in patients with hepatocellular carcinoma (HCC).
Methods
30 cirrhotic patients underwent multiphasic MDCT in the 90 days before liver transplantation. MDCT was performed before contrast medium administration and during hepatic arterial hepatic venous and delayed phases, images were obtained at 12, 55 and 120 s after trigger threshold. Two radiologists qualitatively evaluated images for lesion attenuation. Tumour washout was evaluated subjectively and objectively. Tumour-to-liver contrast (TLC) was measured for all pathologically proven HCCs.
Results
48 HCCs were detected at MDCT. 46 of the 48 tumours (96%) appeared as either hyper- or isoattenuating during the hepatic arterial phase subjective washout was present in 15 HCCs (33%) during the hepatic venous phase and in 35 (76%) during the delayed phase (p<0.001, McNemar’s test). Objective washout was present in 30 of the 46 HCCs (65%) during the hepatic venous phase and in 42 of the HCCs (91%) during the delayed phase (p=0.001). The delayed phase yielded significantly higher mean TLC absolute values compared with the hepatic venous phase (−16.1±10.8 HU vs −10.5±10.2 HU; p<0.001).
Conclusions
The delayed phase is superior to the hepatic venous phase for detection of tumour washout of pathologically proven HCC in cirrhotic patients.
doi:10.1259/bjr/18329080
PMCID: PMC3473662  PMID: 21081569
10.  Characteristics of paraesophageal varices: A study with 64-row multidetector computed tomography portal venography 
AIM: To identify the characteristics of morphology, location and collateral circulation involved in paraesophageal varices (para-EV) of portal hypertension patients with 64-row multidetector computed tomography (MDCT).
METHODS: Fifty-two of 501 patients with portal hypertensive cirrhosis accompanied with esophageal varices were selected for 64-row MDCT examination after the observation of para-EV. The CT protocol included unenhanced, arterial and portal phases with a slice thickness of 0.625 mm and a scanning field of 2 cm above the bifurcation to the lower edge of kidney. The CT portal venography (CTPV) was reformatted on AW4.3 workstation. The characteristics of origination, location, morphology and collateral circulation in para-EV were observed.
RESULTS: Among the 52 cases of para-EV, 50 showed the originations from the posterior branch of left gastric vein, while the others from the anterior branch. Fifty cases demonstrated their locations close to the esophageal-gastric junction, and the other two cases were extended to the inferior bifurcation of the trachea. The circuitous pattern was observed in 16 cases, while reticulated pattern was seen in 36 cases. Collateral circulation identified 4 cases of single periesophageal varices (peri-EV) communication, 3 cases of single hemiazygous vein, one case of single inferior vena cava, 41 cases of mixed type (collateral communications of at least 2 of above mentioned types) and 3 cases of undetermined communications. Among all the cases, 43 patients showed the communications between para-EV and peri-EV, while hemiazygous vein (43 cases) and inferior vena cava (5 cases) were also involved.
CONCLUSION: Sixty-four-row multidetector computed tomography portal venography could display the location, morphology, origin, and collateral types of para-EV, which provides important and referable information for clinical management and disease prognosis.
doi:10.3748/wjg.14.5331
PMCID: PMC2744066  PMID: 18785288
Computer tomography; Portal venography; Paraesophageal varices; Hepatic cirrhosis; Portal hypertension
11.  Effect of Thin Overlapping Reconstruction on the Attenuation of Small (≤ 3 cm) Renal Cysts in the Nephrographic Phase of MDCT: a Phantom Study 
Korean Journal of Radiology  2006;7(4):275-280.
Objective
To evaluate the effect of thin overlapping reconstruction on the attenuation of small (≤ 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 ≤ 20 mm on the 4-channel MDCT.
doi:10.3348/kjr.2006.7.4.275
PMCID: PMC2667614  PMID: 17143031
Kidney; Cyst; Computed tomography (CT); Pseudoenhancement
12.  Correlation between Aortic Wall Thickness and Coronary Artery Disease by 64 Slice Multidetector Computed Tomography 
Introduction: Atherosclerotic cardiovascular disease is a dispersed pathology involving the coronary arteries, carotid arteries, aorta and peripheral arteries. It has been previously suggested that coronary and aortic atherosclerosis may be associated. Imaging of the aorta and the aortic wall can be performed by various imaging modalities including state-of-the-art multidetector computer tomography (MDCT). This study aimed to investigate a possible association between the MDCT-measured thickness of the thoracic aorta and the presence of coronary artery disease (CAD) as well as its severity.
Methods: Three hundred and fifty candidates of coronary computer tomography angiography (CTA) with signs and symptoms suggestive of CAD were recruited in Tabriz Parsian and Iran CTA Centers. Contrast-enhanced MDCT examinations were performed using a 64 detector scanner. Maximum aortic wall thickness in the mid-portion of descending thoracic aorta (region of pulmonary trunk to diaphragm) was measured perpendicular to the center of the vessel.
Results: CAD was confirmed in 189 cases (54%) and the remaining 161 cases served as controls. The mean age of the cases, as well as the percentage of male subjects was significantly higher in the CAD group. The mean aortic wall thickness was also significantly higher in the patient group (2.21±0.63 mm vs. 1.88±0.58 mm; P<0.001). In multivariate analysis, however, the two groups turned up comparable as to the aortic wall thickness (P=0.31). The optimal cut-off point of aortic wall thickness was ≥2 mm in discriminating between CAD+ and CAD- groups, with a corresponding sensitivity and specificity of 65% and 57%, respectively. There was no significant association between aortic wall thickness and the severity of CAD (the number of significantly occluded coronary arteries).
Conclusion: Aortic wall thickness is apparently neither an independent predictor of CAD nor is it associated with the severity of CAD in candidates of CTA.
doi:10.5681/jcvtr.2013.020
PMCID: PMC3825395  PMID: 24252983
Coronary Artery Disease; Multidetector Computer; Tomography; Aortic Wall Thickness
13.  Evaluation of Reperfused Myocardial Infarction by Low-Dose Multidetector Computed Tomography Using Prospective Electrocardiography (ECG)-Triggering: Comparison with Magnetic Resonance Imaging 
Yonsei Medical Journal  2010;51(5):683-691.
Purpose
To evaluate the potential of prospective electrocardiography (ECG)-gated 64-slice multidetector computed tomography (MDCT) for evaluation of myocardial enhancement, infarct size, and stent patency after percutaneous coronary intervention (PCI) with stenting in patients with myocardial infarction.
Materials and Methods
Seventeen patients who were admitted with acute myocardial infarction were examined with prospective ECG-gated 64-slice cardiac MDCT and magnetic resonance (MR) imaging after reperfusion using PCI with stenting. Cardiac MDCT was performed with two different phases: arterial and delayed phases. We evaluated the stent patency on the arterial phase, and nonviable myocardium on the delayed phase of computed tomography (CT) image, and they were compared with the results from the delayed MR images.
Results
Total mean radiation dose was 7.7 ± 0.5 mSv on the two phases of CT images. All patients except one showed good patency of the stent at the culprit lesion on the arterial phase CT images. All patients had hyperenhanced area on the delayed phase CT images, which correlated well with those on the delayed phase MR images, with a mean difference of 1.6% (20 ± 10% vs. 22 ± 10%, r = 0.935, p = 0.10). Delayed MR images had a better contrast-to-noise ratio (CNR) than delayed CT images (27.1 ± 17.8% vs. 4.3 ± 2.1%, p < 0.001).
Conclusion
Prospective ECG-gated 64-slice MDCT provides the potential to evaluate myocardial viability on delayed phase as well as for stent patency on arterial phase with an acceptable radiation dose after PCI with stenting in patients with myocardial infarction.
doi:10.3349/ymj.2010.51.5.683
PMCID: PMC2908876  PMID: 20635442
Prospective ECG-gated MDCT; magnetic resonance imaging; myocardial infarction; delayed enhancement imaging
14.  Validation of Multi-Detector Computed Tomography as a Non-Invasive Method for Measuring Ovarian Volume in Macaques (Macaca fascicularis) 
American journal of primatology  2010;72(6):530-538.
The purpose of this study was to validate low radiation dose, contrast-enhanced, multi-detector computed tomography (MDCT) as a non-invasive method for measuring ovarian volume in macaques. Computed tomography scans of four known-volume phantoms and nine mature female cynomolgus macaques were acquired using a previously described, low radiation dose scanning protocol, intravenous contrast enhancement, and a 32-slice MDCT scanner. Immediately following MDCT, ovaries were surgically removed and the ovarian weights were measured. The ovarian volumes were determined using water displacement. A veterinary radiologist who was unaware of actual volumes measured ovarian CT volumes three times, using a laptop computer, pen display tablet, hand-traced regions of interest, and free image analysis software. A statistician selected and performed all tests comparing the actual and CT data. Ovaries were successfully located in all MDCT scans. The iliac arteries and veins, uterus, fallopian tubes, cervix, ureters, urinary bladder, rectum, and colon were also consistently visualized. Large antral follicles were detected in six ovaries. Phantom mean CT volume was 0.702±SD 0.504 cc and the mean actual volume was 0.743±SD 0.526 cc. Ovary mean CT volume was 0.258±SD 0.159 cc and mean water displacement volume was 0.257±SD 0.145 cc. For phantoms, the mean coefficient of variation for CT volumes was 2.5%. For ovaries, the least squares mean coefficient of variation for CT volumes was 5.4%. The ovarian CT volume was significantly associated with actual ovarian volume (ICC coefficient 0.79, regression coefficient 0.5, P = 0.0006) and the actual ovarian weight (ICC coefficient 0.62, regression coefficient 0.6, P = 0.015). There was no association between the CT volume accuracy and mean ovarian CT density (degree of intravenous contrast enhancement), and there was no proportional or fixed bias in the CT volume measurements. Findings from this study indicate that MDCT is a valid non-invasive technique for measuring the ovarian volume in macaques.
doi:10.1002/ajp.20807
PMCID: PMC3741054  PMID: 20131358
macaque; menopause; ovary volume; computed tomography; MDCT
15.  Pre-operative evaluation of peritoneal deposits using multidetector computed tomography in ovarian cancer 
The British Journal of Radiology  2011;84(997):38-43.
Objective
In the management of epithelial ovarian cancer (EOC), the identification of peritoneal deposits is the most important prognostic factor. We conducted a prospective study to evaluate the role of multidetector CT (MDCT) in identifying peritoneal deposits pre-operatively.
Methods
38 previously untreated patients (median age 50 years; range 26–70 years) were evaluated with contrast-enhanced MDCT of the abdomen and pelvis. All CT scans were performed on a four-slice MDCT scanner with thin-slice image acquisition. Multiplanar coronal, sagittal or oblique images were constructed and all images were reviewed by at least two radiologists. The extent of disease was determined and mapped for all areas of the abdomen and pelvis. CT scans were reviewed and compared with surgical findings. Peritoneal deposits and thickening were separately noted for each of the nine segments of the abdomen and pelvis (i.e. bilateral hypochondria, bilateral lumbar, bilateral iliac fossa, epigastrium, umbilical region and hypogastrium) and were mainly used to determine the accuracy of MDCT in the depiction of peritoneal carcinomatosis.
Results
Sensitivity, specificity, positive and negative predictive values and accuracy of CT in the detection of peritoneal deposits were similar to those reported in the literature. The most common anatomical sites to have peritoneal deposits were the pouch of Douglas (18 cases) and the right subdiaphragmatic region (18 cases).
Conclusion
Despite the improved scanning technology, image reconstruction and viewing ability of MDCT, its overall accuracy for the detection of peritoneal deposits is not significantly improved when compared with conventional CT; however, MDCT is useful in the assessment of disease at specific locations in the abdomen and pelvis.
doi:10.1259/bjr/87415692
PMCID: PMC3473805  PMID: 20858663
16.  Comprehensive evaluation of preoperative patients with aortic valve stenosis: usefulness of cardiac multidetector computed tomography 
Heart  2007;93(9):1121-1125.
Background
Preoperative assessment of patients with aortic valve stenosis (AS) relies on the evaluation of AS severity (aortic valve area, AVA) and left ventricular ejection fraction (LVEF) by echocardiography, and of coronary artery anatomy by coronary angiography.
Aim
To evaluate the feasibility and accuracy of contrast‐enhanced multidetector computed tomography (MDCT), as a single non‐invasive preoperative test, for simultaneous evaluation of the AVA, LVEF and coronary status in patients with AS.
Methods
40 consecutive patients with AS scheduled for aortic valve replacement underwent transthoracic echocardiography, electrocardiogram (ECG)‐gated MDCT and coronary angiography within a time span of 1 week.
Results
MDCT measurements could be performed in all patients. A good correlation but a slight overestimation was observed between mean (SD) AVA measured by MDCT and by echocardiography (0.87 (0.22) vs 0.81 (0.20) cm2, p = 0.01; r = 0.77, p<0.001). Mean difference between methods was 0.06 (0.15) cm2. LVEF measured by MDCT correlated well with, and did not differ from, electrocardiographic measurements (59% (13%) vs 61% (10%), p = 0.34; r = 0.76, p<0.001; mean difference 1% (8%)). Coronary angiography displayed 33 lesions in 13 patients. MDCT correctly identified 26 of these 33 lesions and overestimated three <50% stenosis. On a segment‐by‐segment analysis, MDCT sensitivity, specificity, positive and negative predictive values were 79%, 99%, 90% and 98%, respectively. For each patient, MDCT had a sensitivity of 85% (11/13 patients), a specificity of 93% (25/27 patients) and positive and negative predictive values of 85% (11/13 patients) and 93% (25/27 patients), respectively.
Conclusion
MDCT can provide a simultaneous and accurate evaluation of the AVA, LVEF and coronary artery anatomy in patients with AS. In the near future, with technological improvements, MDCT could achieve an exhaustive and comprehensive preoperative assessment of patients with AS. In addition, for the assessment of AS severity in difficult cases, MDCT could be considered as an alternative to transoesophageal echocardiography or cardiac catheterisation.
doi:10.1136/hrt.2006.107284
PMCID: PMC1955027  PMID: 17483132
17.  CT Coronary Angiography: 256-Slice and 320-Detector Row Scanners 
Current cardiology reports  2010;12(1):68-75.
Multidetector computed tomography (MDCT) has rapidly evolved from 4-detector row systems in 1998 to 256-slice and 320-detector row CT systems. With smaller detector element size and faster gantry rotation speed, spatial and temporal resolution of the 64-detector MDCT scanners have made coronary artery imaging a reliable clinical test. Wide-area coverage MDCT, such as the 256-slice and 320-detector row MDCT scanners, has enabled volumetric imaging of the entire heart free of stair-step artifacts at a single time point within one cardiac cycle. It is hoped that these improvements will be realized with greater diagnostic accuracy of CT coronary angiography. Such scanners hold promise in performing a rapid high quality “triple rule-out” test without high contrast load, improved myocardial perfusion imaging, and even four-dimensional CT subtraction angiography. These emerging technical advances and novel applications will continue to change the way we study coronary artery disease beyond detecting luminal stenosis.
doi:10.1007/s11886-009-0075-z
PMCID: PMC2893879  PMID: 20425186
Computed tomography; Coronary artery disease; Wide area detector; Imaging; Technology
18.  Prospective evaluation of unsuspected pulmonary embolism on contrast enhanced multidetector CT (MDCT) scanning 
Thorax  2006;62(6):536-540.
Aim
To quantify the incidence of unsuspected pulmonary emboli (PE) in an unselected inpatient population undergoing contrast enhanced multidetector CT (MDCT) scanning of the thorax and to assess aetiological factors in their development.
Methods
All inpatients undergoing MDCT scanning of the thorax over a 10 month period were prospectively identified. Patients with previous or suspected current PE were excluded. CT scans were reviewed and the degree of contrast enhancement and presence of PE recorded. Where PE was found, the level of the most proximal thrombus was identified. Patient age, length of admission, slice scan thickness and clinical indication were noted.
Results
547 inpatients who had undergone MDCT scanning were identified. Following exclusions 487 remained, 28 of whom (5.7%) had PE. Unsuspected PE was more common with increasing age, occurring in 9.2% (20/218) of all patients over 70 years and 16.7% (11/66) of those over 80 years (p<0.001). Eighteen of the 28 positive scans (64.3%) were at the segmental or subsegmental level. No other aetiological factor was identified which significantly increased the incidence of unsuspected PE. No significant difference was noted between 4‐slice and 16‐slice MDCT. Nine of the cases of incidental PE (32.1%) were not identified by the original reporting radiologists.
Conclusion
PE is an unsuspected finding on contrast enhanced MDCT scanning of the thorax in 5.7% of all inpatients. The incidence is higher in older patients. Most are peripheral and >30% are missed on initial review. PE should be routinely sought in all contrast enhanced MDCT scans of the chest, irrespective of the indication for the CT scan.
doi:10.1136/thx.2006.062299
PMCID: PMC2117210  PMID: 17158631
19.  Value of multidetector computed tomography in the diagnosis of mucosa-associated lymphoid tissue-lymphomas in the parotid gland: A case report and review of the literature 
Oncology Letters  2013;7(3):781-786.
The present study aimed to review the multidetector computed tomography (MDCT) imaging features of eight mucosa-associated lymphoid tissue (MALT)-lymphoma cases of the parotid gland and to explore the diagnostic value of MDCT. A total of eight patients with pathologically confirmed MALT-lymphomas of the parotid gland underwent pre-operative MDCT plain and dual-phase scans. The changes in the CT values and enhancement patterns of the tumors were assessed. Quantitative analysis was performed to determine the CT value changes of the tumors in the various enhanced phases compared with the plain scan. The MALT-lymphomas of the parotid gland exhibited even density isodense or hyperdense nodules, with occasional calcification and necrosis. The dual-phase scan of the MALT-lymphomas revealed a pattern of lower or moderate enhancement, circumambient enhancement or delayed enhancement. The MALT-lymphomas were closely associated with Sjögre’s syndrome and demonstrated malignant features and isodense or hyperdense nodules and lower or moderate enhancement on the CT scans.
doi:10.3892/ol.2013.1769
PMCID: PMC3919924  PMID: 24520295
parotid gland; mucosa-associated lymphoid tissue lymphomas; computer tomography; enhancement
20.  Coronary fly-through or virtual angioscopy using dual-source MDCT data 
European Radiology  2007;17(11):2852-2859.
Coronary fly-through or virtual angioscopy (VA) has been studied ever since its invention in 2000. However, application was limited because it requires an optimal computed tomography (CT) scan and time-consuming post-processing. Recent advances in post-processing software facilitate easy construction of VA, but until now image quality was insufficient in most patients. The introduction of dual-source multidetector CT (MDCT) could enable VA in all patients. Twenty patients were scanned using a dual-source MDCT (Definition, Siemens, Forchheim, Germany) using a standard coronary artery protocol. Post-processing was performed on an Aquarius Workstation (TeraRecon, San Mateo, Calif.). Length travelled per major branch was recorded in millimetres, together with the time required in minutes. VA could be performed in every patient for each of the major coronary arteries. The mean (range) length of the automated fly-through was 80 (32–107) mm for the left anterior descending (LAD), 75 (21–116) mm for the left circumflex artery (LCx), and 109 (21–190) mm for the right coronary artery (RCA). Calcifications and stenoses were visualised, as well as most side branches. The mean time required was 3 min for LAD, 2.5 min for LCx, and 2 min for the RCA. Dual-source MDCT allows for high quality visualisation of the coronary arteries in every patient because scanning with this machine is independent of the heart rate. This is clearly shown by the successful VA in all patients. Potential clinical value of VA should be determined in the near future.
doi:10.1007/s00330-007-0681-3
PMCID: PMC2039819  PMID: 17562048
Virtual angioscopy; Coronary arteries; Coronary fly-through; Post-processing; Dual-source CT
21.  Preoperative and Postoperative Evaluation of Multiple Giant Coronary Aneurysms by the Use of Coronary CT Angiography with 64-MDCT: A Case of Multiple Giant Coronary Aneurysms Treated with Aneurysmectomy and Coronary Artery Bypass Surgery 
Yonsei Medical Journal  2009;50(1):160-163.
A coronary artery aneurysm is an uncommon disorder and is seen as a characteristic dilatation of a localized portion of the coronary artery. Clinical manifestation of a coronary artery aneurysm varies from an asymptomatic presentation to sudden death of a patient. Although coronary aneurysms are typically diagnosed by the use of coronary angiography, a new generation of coronary 64-slice multidetector computed tomography (64-MDCT) scanners have successfully been used for evaluating this abnormality in a noninvasive manner. In the present case, we performed coronary 64-MDCT scanning preoperatively and postoperatively on a patient with multiple giant coronary aneurysms. The use of coronary 64-MDCT may provide an evaluation technique not only for diagnosis but also for follow-up after surgery for this condition.
doi:10.3349/ymj.2009.50.1.160
PMCID: PMC2649873  PMID: 19259365
Coronary aneurysm; computed tomography
22.  Discordance between anatomical and functional coronary stenosis severity 
Netherlands Heart Journal  2007;15(1):5-11.
Background.
New developments have made 16-slice multidetector computed tomography (MDCT) a promising technique for detecting significant coronary stenoses. At present, there is a paucity of data on the relation between fractional flow reserve (FFR) measurement and MDCT stenosis detection.
Objective.
The aim of this study was to investigate the relation between the anatomical severity of coronary artery disease detected by MDCT and functional severity measured by fractional flow reserve (FFR).
Methods.
We studied 53 patients (39 men and 14 women, age 62.5±8.1 years) with single-vessel disease scheduled for percutaneous coronary intervention (PCI). All patients underwent MDCT scanning one day prior to PCI and FFR was measured before PCI in the target vessel.
Results.
MDCT analysis could be performed in 52 of 53 patients (98.1%) and all patients had adequate FFR and quantitative coronary angiography (QCA) measurements. The mean stenosis diameters calculated by MDCT and QCA were 67.0±11.6% and 60.8±11.6% respectively. No significant relation was found between MDCT and QCA (r=0.22, p=0.12) The mean FFR in all patients was 0.67±0.18. A relation of r=-0.46 (p=0.0006) between QCA and FFR was found. In contrast, no relation between MDCT and FFR could be demonstrated (r=–0.09, p=0.50). Furthermore, a high incidence of false-positive and false-negative findings was present in both diagnostic modalities.
Conclusion.
There is no clear relation between the anatomical and functional severity of coronary artery disease as defined by MDCT and FFR. Therefore, functional assessment of coronary artery disease remains mandatory for clinical decisionmaking. (Neth Heart J 2007;15:5-11.)
PMCID: PMC1847721  PMID: 17612701
coronary arteriosclerosis; coronary artery disease; tomography (computed); fractional flow reserve
23.  Multi-detector row computed tomography angiography of peripheral arterial disease 
European Radiology  2007;17(12):3208-3222.
With the introduction of multi-detector row computed tomography (MDCT), scan speed and image quality has improved considerably. Since the longitudinal coverage is no longer a limitation, multi-detector row computed tomography angiography (MDCTA) is increasingly used to depict the peripheral arterial runoff. Hence, it is important to know the advantages and limitations of this new non-invasive alternative for the reference test, digital subtraction angiography. Optimization of the acquisition parameters and the contrast delivery is important to achieve a reliable enhancement of the entire arterial runoff in patients with peripheral arterial disease (PAD) using fast CT scanners. The purpose of this review is to discuss the different scanning and injection protocols using 4-, 16-, and 64-detector row CT scanners, to propose effective methods to evaluate and to present large data sets, to discuss its clinical value and major limitations, and to review the literature on the validity, reliability, and cost-effectiveness of multi-detector row CT in the evaluation of PAD.
doi:10.1007/s00330-007-0729-4
PMCID: PMC2077918  PMID: 17882427
Human; Peripheral vascular diseases; Radiography; Tomography; X-ray computed methods; Reproducibility of results; Sensitivity and specificity
24.  Contrast-Enhanced Multidetector Computed Tomography Viability Imaging After Myocardial Infarction 
Circulation  2006;113(3):394-404.
Background
The ability to distinguish dysfunctional but viable myocardium from nonviable tissue has important prognostic implications after myocardial infarction. The purpose of this study was to validate the accuracy of contrast-enhanced multidetector computed tomography (MDCT) for quantifying myocardial necrosis, microvascular obstruction, and chronic scar after occlusion/reperfusion myocardial infarction.
Methods and Results
Ten dogs and 7 pigs underwent balloon occlusion of the left anterior descending coronary artery (LAD) followed by reperfusion. Contrast-enhanced (Visipaque, 150 mL, 325 mg/mL) MDCT (0.5 mm × 32 slice) was performed before occlusion and 90 minutes (canine) or 8 weeks (porcine) after reperfusion. MDCT images were analyzed to define infarct size/extent and microvascular obstruction and compared with postmortem myocardial staining (triphenyltetrazolium chloride) and microsphere blood flow measurements. Acute and chronic infarcts by MDCT were characterized by hyperenhancement, whereas regions of microvascular obstruction were characterized by hypoenhancement. MDCT infarct volume compared well with triphenyltetrazolium chloride staining (acute infarcts 21.1±7.2% versus 20.4±7.4%, mean difference 0.7%; chronic infarcts 4.15±1.93% versus 4.92±2.06%, mean difference −0.76%) and accurately reflected morphology and the transmural extent of injury in all animals. Peak hyperenhancement of infarcted regions occurred ≈5 minutes after contrast injection. MDCT-derived regions of microvascular obstruction were also identified accurately in acute studies and correlated with reduced flow regions as measured by microsphere blood flow.
Conclusions
The spatial extent of acute and healed myocardial infarction can be determined and quantified accurately with contrast-enhanced MDCT. This feature, combined with existing high-resolution MDCT coronary angiography, may have important implications for the comprehensive assessment of cardiovascular disease.
doi:10.1161/CIRCULATIONAHA.105.521450
PMCID: PMC3410562  PMID: 16432071
tomography; heart diseases; imaging; contrast media; myocardial infarction
25.  Role of multidetector computed tomography (MDCT) in patients with ovarian masses 
Objective:
To evaluate the diagnostic accuracy of multidetector 64-slice computed tomography (MDCT) in the diagnosis and differentiation of benign and malignant ovarian masses using histopathology and surgical findings as the gold standard.
Material and methods:
This study was conducted in Aga Khan University Hospital, Karachi, Pakistan. Data was reviewed retrospectively from 1 November 2008 to 12 December 2009. One hundred patients found to have ovarian masses on CT scan were included in the study. CT scan was performed in all these patients after administration of oral and IV contrast. Ovarian masses were classified as benign and malignant on scan findings. Imaging findings were compared with histopathologic results and surgical findings. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and diagnostic accuracy of MDCT were calculated.
Results:
MDCT was found to have 97% sensitivity, 91% specificity, and an accuracy of 96% in the differentiation of benign and malignant ovarian masses, while PPV and NPV were 97% and 91%, respectively.
Conclusion:
MDCT imaging offers a safe, accurate and noninvasive modality to differentiate between benign and malignant ovarian masses.
doi:10.2147/IJWH.S15501
PMCID: PMC3089430  PMID: 21573148
ovarian masses; surgery; MDCT

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