Contrast Injection Technique Research Articles

Excimer laser coronary angioplasty combined with drug-coated balloon in the treatment of in-stent restenosis.

The aim of this study is to investigate the safety and efficacy of excimer laser coronary angioplasty (ELCA) combined with drug-coated balloons(DCBs) in the treatment of in-stent restenosis (ISR), and to explore whether the contrast injection technique would improve the neointimal tissue ablation of ELCA. We studied patients diagnosed with ISR between January 2019 and October 2022 at two medical centers. These patients underwent DCB angioplasty guided by optical coherence tomography (OCT). Based on whether ELCA was performed before DCB treatment, patients were categorized into two groups: the ELCA + DCB group and the DCB group. All patients underwent clinical follow-up 1 year after the procedure. The primary endpoint was the 1-year rate of target lesion revascularization (TLR), which was defined as any repeat percutaneous intervention or bypass surgery on the target vessel conducted to address restenosis or other complications related to the target lesion. The secondary endpoints including immediate luminal gain (ΔMLA, defined as the difference in minimum lumen area before and after the intervention). A total of 85 lesions in 75 patients were included. The mean age of the study population was 64.2 ± 12.0 years, with 81.3% male. Baseline clinical characteristics were well-balanced, and procedural success was 100% in both groups. The ELCA + DCB group (n = 24) exhibited a greater ΔMLA compared to the DCB group (n = 61) (3.57 ± 0.79 mm² vs. 2.50 ± 1.06 mm², [95% confidence interval,CI: 0.57-1.69], p < 0.001), The reduction in 1-year TLR was more frequently observed in patients from the ELCA + DCB group compared to the DCB group (hazard ratio 0.33 [95% CI: 0.11-0.99]; log-rank p = 0.048). The exploratory analysis showed that ELCA with contrast infusion is associated with greater acute lumen gain compared to ELCA with saline infusion (p < 0.001). The combination of ELCA and DCB is a safe and effective treatment strategy for in-stent stenosis. Additionally, compared with saline injection, ELCA with contrast injection is associated with greater acute lumen gain. However, the optimal contrast agent concentration and long-term outcome of the contrast injection technique need confirmation through larger sample sizes and prospective studies.

"The microcatheter contrast injection technique": A novel technique to detect the proximal end of a thrombus in mechanical thrombectomy.

Background: An aspiration catheter needs to attach to a thrombus in order to achieve first-pass recanalization by mechanical thrombectomy (MT) for acute ischemic stroke (AIS), particularly that using a direct aspiration first pass technique. The meniscus sign, which is defined as meniscoid contrast opacification indicating the proximal edge of a thrombus, has been suggested to contribute to successful recanalization. In some cases, the meniscus sign is not detected following an injection of contrast medium through a guiding catheter. To precisely identify the location of a thrombus, we use "the microcatheter contrast injection (MCI) technique," which accurately shows the proximal edge of a thrombus. We herein introduce this novel technique and discuss its efficacy in MT. Methods: In cases without the meniscus sign, a microcatheter was advanced to the distal end of contrast opacification, and contrast medium was injected through the microcatheter to detect the meniscus sign. An aspiration catheter was then advanced to the thrombus indicated by the meniscus sign and slowly withdrawn under aspiration. Results: 29 patients underwent MT for AIS using the MCI technique. Even in cases without the meniscus sign on initial angiography, the MCI technique accurately revealed the proximal edge of the thrombus. Moreover, middle cerebral artery occlusion due to atherosclerotic stenosis and displacement of the aspiration catheter and thrombus axis were detected using this technique. Conclusions: The MCI technique may effectively reveal the exact site of a thrombus and increase the success rate of first-pass recanalization.

Shoulder magnetic resonance arthrography in dogs: Comparison of craniolateral and caudolateral approach for ultrasound-guided contrast injection.

Shoulder joint disease is a common cause of forelimb lameness in dogs. To diagnose this condition, shoulder magnetic resonance arthrography (MRA) is performed, which involves the injection of contrast agents into the shoulder joint space under ultrasound (US)-guidance. The objective of this study was to compare the craniolateral and caudolateral approaches for shoulder MRA using US-guided injection techniques, and investigate their clinical feasibility in dogs. Forty shoulder joints from 10 adult beagles were studied in two repetitions. The craniolateral (n = 20) and caudolateral (n = 20) injection techniques were applied randomly under US-guidance. The shoulder MRA was conducted immediately after the contrast agents was injected. The procedure time (scan and injection time), number of attempts, joint distension and degree of extraarticular extravasation were recorded and compared between the two groups. The results showed that the caudolateral approach had significantly more contrast agents extravasation compared to the craniolateral approach (p < 0.05). However, there were no significant differences between the two groups in terms of procedure time (scan time p = 0.80, injection time p = 0.74), number of attempts (p = 0.70) and joint distension (p = 0.23). The craniolateral approach of US-guided contrast injection techniques for shoulder MRA minimizes damage to the juxta-articular structures and reduces extraarticular extravasation, resulting in good-quality images. This study demonstrates the feasibility and advantages of the craniolateral approach under US-guidance for shoulder MRA in dogs.

Geometrically independent contrast dilution gradient (CDG) velocimetry using photon-counting 1000 fps High Speed Angiography (HSA) for 2D velocity distribution estimation.

Previous studies have demonstrated the efficacy of contrast dilution gradient (CDG) analysis in determining large vessel velocity distributions from 1000 fps high-speed angiography (HSA). However, the method required vessel centerline extraction, which made it applicable only to non-tortuous geometries using a highly specific contrast injection technique. This study seeks to remove the need for a priori knowledge regarding the direction of flow and modify the vessel sampling method to make the algorithm more robust to non-linear geometries. 1000 fps HSA acquisitions were obtained in vitro with a benchtop flow loop using the XC-Actaeon (Varex Inc.) photon-counting detector, and in silico using a passive-scalar transport model within a computational fluid dynamics (CFD) simulation. CDG analyses were obtained using gridline sampling across the vessel, and subsequent 1D velocity measurement in both the x- and y-directions. The velocity magnitudes derived from the component CDG velocity vectors were aligned with CFD results via co-registration of the resulting velocity maps and compared using mean absolute percent error (MAPE) between pixels values in each method after temporal averaging of the 1-ms velocity distributions. Regions well-saturated with contrast throughout the acquisition showed agreement when compared to CFD (MAPE of 18% for the carotid bifurcation inlet and MAPE of 27% for the internal carotid aneurysm), with respective completion times of 137 seconds and 5.8 seconds. CDG may be used to obtain velocity distributions in and surrounding vascular pathologies provided the contrast injection is sufficient to provide a gradient, and diffusion of contrast through the system is negligible.

Radio-carpal wrist MR arthrography: comparison of ultrasound with fluoroscopy and palpation-guided injections.

To compare ultrasound- (US), fluoroscopy- (FL), and palpation-guided contrast injection techniques used for dorsal radio-carpal wrist MRA. Patients with chronic wrist pain were randomized as to which injection technique they underwent into three groups of 50 participants. Dorsal radio-carpal contrast injection was performed under US, FL guidance (one radiologist for each), or palpation guidance by an orthopedic surgeon. The three techniques were compared by procedure time, success rate, number of attempts needed, frequency and grade of extravasation, joint distension, and MRA image quality. Additionally, any change from baseline wrist pain was recorded using the visual analog scale (VAS) at five time points (immediately, 8h, 24h, 48h, and 1week) after injection. One hundred and fifty patients (83 males and 67 females; mean age 29 ± 6.5years) were included. Success rates for US- and FL-guided injections were 100%, while palpation-guided approach was significantly less successful (72%) (P = 0.02) with significantly more frequent extravasation (56%)(P < 0.001). US guidance was the least time-consuming (6.5 ± 1.6min) compared to FL guidance (12.5 ± 1.9min) and palpation guidance (8 ± 1.2min) (all P < 0.001). The mean number of joint puncture attempts was significantly lower with imaging-guided techniques (1.1 ± 0.24 and 1.2 ± 0.4 for US and FL, P = 0.23) compared to palpation-guided one (1.6 ± 0.8) (P = 0.007). The largest increases in baseline-pain were 8-h post-injection, and US guidance was the least painful at all-time points (all P < 0.05). Joint distension and image quality were significantly better with imaging-guided techniques (P < 0.001 and P = 0.003). US-guided radio-carpal injection is a less time-consuming, more tolerable, and successful radiation-free method when compared to FL guidance. Palpation-guided injections require multiple attempts to enter the joint with high failure rates and frequent extravasation.

Comparative Analysis of Artery Anatomy Evaluated by Postmortem Tomography, CT Angiography, and Postmortem and Predeath CT Scans

To date, no study has been performed analyzing changes in the vascular system comparing paired examinations of patients alive and after death with the use of cardiopulmonary bypass and computed tomography (CT) angiography. The aim of this study was to analyze in a large series (38 patients) the aorta and its branches by CT (without contrast) and CT angiography of patients still alive and after death comparing their diameters and length variations. The variation between invivo tomography and virtopsy methods was greater in the evaluation of distances between vascular segments than in the diameters; less than 30% of the distances evaluated in the entire study had acceptable variation between methods, regardless of the use of contrast scans. We observed better repeatability rates in the comparison between invivo and postmortem contrast-enhanced examinations. Comparing the examinations of the still alive individuals with the contrast-enhanced tomography after death, we observed a higher concordance rate. The best variations between the methods were observed in the evaluation of the diameters in the contrast-enhanced examination of the ascending aorta, aortic arch, thoracic aorta, and thoracoabdominal transition. The measurements obtained in postmortem angiography images partially reflect the vascular anatomy of the main branches in the thoracoabdominal region invivo. However, postmortem CT without contrast was not performed in the same comparison. We believe that adjustments to the contrast injection technique may eventually improve these results.

Utility of the Contrast Injection Technique Using the Diluted Test Injection Method and the Test Bolus Tracking Method in the Coronary CT Angiography

Although the test bolus tracking method is available as a predicting method of scan timing in the coronary computed tomography (CT) angiography, it is known that there is a problem of scan timing due to the use of a part of test bolus method. The diluted test bolus method was adopted for test bolus, and as a result of using in combination with the test bolus tracking method, it showed a higher contrast enhancement compared with the test bolus tracking method; a stable contrast enhancement with less variation in CT number was obtained. The CT number at the peak in the test scan and the CT number of the main scan showed a high correlation. The contrast injection technique using the diluted test bolus method and the test bolus tracking method is a useful method in the coronary CT angiography. We named this contrast injection technique diluted test bolus tracking method.

Simplified split-bolus intravenous contrast injection technique for pediatric abdominal CT

PurposeTo investigate pediatric abdominal CT using a simplified split-bolus (Split group) contrast injection compared with a single bolus (Control group). MethodsRadiation dose, image quality and diagnostic accuracy were compared. ResultsSplit group demonstrated lower effective dose (2.46 vs. 2.85mSv, p=0.002) and noise levels in aorta, liver and portal vein (p<0.001). There was one false-negative case of portal vein obliteration in the Split group. ConclusionsA simple method of split-bolus intravenous contrast injection technique can provide adequate and homogeneous enhancement in pediatric abdominal CT.

Estimation of time to peak contrast enhancement of the aorta and liver for dual-phase computed tomography on the basis of contrast medium arrival time, injection duration, and injection technique in dogs.

OBJECTIVE To evaluate the accuracy of estimating time to peak enhancement (TPE) of the aorta and liver parenchyma on the basis of contrast medium arrival time in the aorta, injection duration, and injection technique in dogs. ANIMALS 18 dogs of specific body weight categories (≥ 2 dogs/category) with no liver abnormalities detected via CT. PROCEDURES Dogs were randomly assigned within weight categories to receive contrast medium IV at a fixed injection rate (5 mL/s) or fixed injection duration (20 seconds). Time-contrast attenuation curves were generated from dynamic CT scans acquired at the hepatic hilus. Data collected for contrast medium arrival time and injection duration were used to estimate TPEs of the aorta and liver, and results were compared with the observed TPEs for the aorta and liver. RESULTS Contrast medium arrival time, injection duration, and injection technique were significantly associated with observed values for aortic TPE and explained 96.1% of variation in TPE. For the fixed rate technique, the regression equation for estimating aortic TPE was 0.8 × (injection duration + contrast medium arrival time) + 1.6. For the fixed duration technique, the regression equation changed by only the constant (-2.6). However, the hepatic TPE estimated from the 3 predictor variables was not significantly different from the mean of observed TPEs. CONCLUSIONS AND CLINICAL RELEVANCE Aortic TPE could be accurately estimated from contrast medium arrival time, injection duration, and injection technique in dogs with apparently healthy livers. The regression equations derived from this relationship can be used to improve the efficiency of dual-phase CT of the liver in dogs.

Spinal arteriovenous shunts: accuracy of shunt detection, localization, and subtype discrimination using spinal magnetic resonance angiography and manual contrast injection using a syringe.

The object of this study was to evaluate the accuracy of fast 3D contrast-enhanced spinal MR angiography (MRA) using a manual syringe contrast injection technique for detecting and evaluating spinal arteriovenous shunts (AVSs). This was a retrospective study of 15 patients and 20 spinal MRA and catheter angiography studies. The accuracy of using spinal MRA to detect spinal AVS, localize shunts, and discriminate the subtype and dominant arterial feeder of the AVS were studied. There were 14 pretherapeutic and 6 posttherapeutic follow-up spinal MRA and catheter spinal angiography studies. The spinal AVS was demonstrated in 17 of 20 studies. Spinal MRA demonstrated 100% sensitivity for detecting spinal AVS with no false-negative results. A 97% accuracy rate for AVS subtype discrimination and shunt level localization was achieved using this study's diagnostic criteria. The detection of the dominant arterial feeder was limited to 9 of these 17 cases (53%). The fast 3D contrast-enhanced MRA technique performed using manual syringe contrast injection can detect the presence of a spinal AVS, locate the shunt level, and discriminate AVS subtype in most cases, but is limited when detecting small arterial feeders.

Value of triple rule-out CT in the emergency department

BackgroundTriple-rule-out (TRO) computed tomographic (CT) angiography is a recent technique for evaluation of the coronary arteries, aorta, pulmonary arteries, and adjacent intrathoracic structures simultaneously for patients with acute chest pain. ObjectivesTo assess the validity and efficacy of Triple-rule-out (TRO) computed tomographic (CT) angiography in diagnosis of different vascular causes of chest pain in the emergency department. MethodsBetween April 2013 and December 2014, 40 patients presenting with non-specific acute chest pain to the emergency department performed Triple-rule-out (TRO) computed tomographic (CT) angiography utilizing a biphasic contrast injection technique. The CT angiographic images were interpreted prospectively for detection of any pulmonary, coronary or aortic vascular abnormalities. ResultsThe study revealed 20 cases (50%) with only coronary lesions, 5 cases (12.5%) with only pulmonary lesions, 10 cases (25%) with only aortic lesions and 3 cases (7.5%) with combined coronary/aortic lesions. 2 cases (5%) showed no significant vascular abnormality. ConclusionAn optimized TRO protocol with concomitant reduced radiation exposure and efficient contrast agent administration provides a reliable tool for evaluation of coronary, aortic and pulmonary arteries in the emergency department.

The retrobulbar sinus is superior to the lateral tail vein for the injection of contrast media in small animal cardiac imaging

Cardiac perfusion studies using computed tomography are a common tool in clinical practice. Recent technical advances and the availability of dedicated small animal scanners allow the transfer of these techniques to the preclinical sector in general and to mouse models of cardiac diseases in particular. This necessitates new requirements for contrast injection techniques as a rapid transport of contrast media from the intravenous access to the animal heart. Clinical contrast agents containing high iodine concentrations are used within small animal studies although they exhibit a high viscosity which might limit their transport within the vasculature. The authors provide a comparison of the transport of contrast media following an injection into the lateral tail vein and an injection into the retrobulbar sinus and discuss the anatomy involved. The temporal evolution of a contrast bolus and its invivo distribution is visualized. It is demonstrated that injecting contrast agents into the lateral tail vein of mice results in a retrograde blood flow to the liver veins and therefore does not deliver a detectable contrast bolus to the heart, and thus it cannot be used for cardiac perfusion studies. By contrast, boli injected into the retrobulbar sinus are rapidly transported to the heart and provide ventricular contrast enabling perfusion studies similar to those in human patients. The results demonstrate that an injection into the retrobulbar sinus is superior to an injection into the lateral tail vein for the delivery of contrast boli to the animal heart, while all drawbacks of an injection into the lateral tail vein are overcome.

Review of catheter venography protocols in the evaluation of chronic cerebrospinal venous insufficiency

Catheter venography has been considered to be the gold standard in the evaluation of venous pathology. Chronic cerebrospinal venous insufficiency (CCSVI) has recent- ly been described as a condition characterised by the presence of multiple stenotic lesions of the main pathways of extracranial venous drainage, especially the internal jugular veins and the azygos vein. The primary screening diagnostic method to identi- fy the venous lesions has been Doppler sonography. Once the abnormalities are iden- tified by the non-invasive method, patients undergo catheter venography to confirm the presence of venous lesions with the aim of performing treatment, which has main- ly been balloon angioplasty. Since the inception of CCSVI, several venographic pro- tocols to evaluate the internal jugular and azygos veins have been described, but none of them have been scientifically validated. The purpose of this review is to analyse the most recent catheter venography protocols reported for the diagnosis and manage- ment of CCSVI. The materials and methods sections of the most recently published series describing catheter venography for the evaluation and management for CCSVI were reviewed. The technical details, including venous access selection site, catheter selection, ideal catheter position, contrast injection techniques, and interpretation of venographic findings, were reviewed. Comments on each of the technical factors are presented. Final comments with proposed techniques are presented.

The influence of noise on BOLD-mediated vessel size imaging analysis methods.

Vessel size imaging (VSI) is a magnetic resonance imaging (MRI) technique that aims to provide quantitative measurements of tissue microvasculature. An emerging variation of this technique uses the blood oxygenation level-dependent (BOLD) effect as the source of the imaging contrast. Gas challenges have the advantage over contrast injection techniques in that they are noninvasive and easily repeatable because of the fast washout of the contrast. However, initial results from BOLD-VSI studies are somewhat contradictory, with substantially different estimates of the mean vessel radius. Owing to BOLD-VSI being an emerging technique, there is not yet a standard processing methodology, and different techniques have been used to calculate the mean vessel radius and reject uncertain estimates. In addition, the acquisition methodology and signal modeling vary from group to group. Owing to these differences, it is difficult to determine the source of this variation. Here we use computer modeling to assess the impact of noise on the accuracy and precision of different BOLD-VSI calculations. Our results show both potential overestimates and underestimates of the mean vessel radius, which is confirmed with a validation study at 3T.

Comparison of Aortic Arch and Intravenous Contrast Injection Techniques for C-arm Cone Beam CT: Implications for Cerebral Perfusion Imaging in the Angiography Suite

The ability to perform cerebral perfusion imaging (CPI) in the angiography suite has provided a new tool for diagnosis and treatment of neurovascular patients but requires comparable contrast perfusion to each cerebral hemisphere. In the angiography suite, contrast injection may be performed via an intra-arterial or intravenous (IV) route. The purpose of this study was to investigate whether a difference exists between contrast injection in the aortic arch (AA) and a peripheral vein (IV), particularly in the setting of stroke. Using three canines, both AA and IV injection protocols compatible with CPI were performed prospectively at three time points after creation of a stroke. The common carotid arteries in the resulting image data sets were segmented and the means and distributions of corresponding pixel intensities analyzed with Student's t-test. Using similar techniques, the internal carotid arteries of three patients (one female, two males, ages 69, 29, and 20) undergoing AA contrast injection with cone beam computed tomography (CBCT) cerebral imaging were analyzed and compared retrospectively with those of three random patients (one female, two males, ages 19, 57, and 35) undergoing standard head CT scans using IV contrast administration. All acquisitions followed institutionally approved protocols and informed consent. No statistical significance (P < .05) was found when mean values for the right and left carotid artery pixel intensities were compared in the canine model or the clinical studies in which patients underwent imaging after AA or IV contrast administration. No statistically significant difference exists between right and left carotid artery filling density using either AA or IV contrast injection methods, making both suitable for CPI in the angiography suite.

Experiences of using a single post-contrast CT scan of the chest after biphasic contrast injection

Computed tomographic chest investigations can be enhanced; in many cases, the arterial phase of a post-contrast arterial and delay (60 seconds) study can be omitted when planning the contrast injection and scanning technique carefully. A biphasic contrast injection was used before starting a single 60-second post-contrast scan.

Guidewire biliary cannulation does not reduce post-ERCP pancreatitis compared with the contrast injection technique in low-risk and high-risk patients

Guidewire (GW) cannulation can reduce the risk of post-ERCP pancreatitis (PEP) by avoiding the opacification of the main pancreatic duct. To compare the effects of conventional contrast ERCP and GW cannulation of the common bile duct on the rate of PEP in low- and high-risk patients. Prospective, comparative-intervention single-center study. Tertiary referral center. Patients with biliary disease with an intact papilla were prospectively examined by ERCP. Biliary cannulation using a sphincterotome with contrast injection (ConI) or a hydrophilic GW without contrast injection. Pancreatitis rate in the GW group and the contrast injection (ConI) group. PEP occurred in 60 of 1249 patients (4.8%), 35 of 678 (5.2%) in the GW group and 25 of 571 (4.4%) in the ConI group (not significant). The overall rate of PEP was significantly higher in high-risk patients (12.2%) than in low-risk patients (3.5%) (P < .001), but was similar for the 2 techniques within each of these 2 groups. In patients with unintended main pancreatic duct (MPD) cannulation or opacification, the rate of PEP was not significantly different with the GW (15.2%) and ConI (8.4%) techniques but was associated with a significantly higher rate of pancreatitis (11.9%) than in patients in whom the contrast medium or GW did not enter the MPD (3.5%) (P < .001). Multivariate analysis indicated that more than 10 papillary cannulation attempts, MPD cannulation or opacification, suspected sphincter of Oddi dysfunction, and precut methods were significant risk factors independently associated with PEP. Lack of randomization. For selective cannulation of the CBD, the risk of inducing PEP is similar with the ConI and GW techniques in high-risk and low-risk patients. Any manipulation of the MPD must be considered a high-risk factor for PEP, such as multiple attempts on the papilla or use of the precut method.

Interatrial shunt: diagnosis of patent foramen ovale and atrial septal defect with 64-row coronary computed tomography angiography

The aim of this study was to investigate the frequency with which interatrial shunts are found during routine coronary computed tomography (CT) angiography and to describe imaging characterizations of patent foramen ovale (PFO), atrial septal defect (ASD), and atrial septal aneurysm (ASA). A total of 1081 adult patients were evaluated retrospectively for interatrial shunting; 77 were excluded from the study. CT diagnosis of PFO was defined as (1) a channel-like appearance of the interatrial septum (IAS) and (2) a contrast agent jet flow from the left atrium (LA) to the right atrium (RA). ASD was defined as (1) the IAS resembling a membrane with a hole and (2) a contrast jet flow between the two atria. ASA was identified by detecting a minimum 10-mm protrusion of the LA beyond the IAS into the RA. Among 1004 patients, 86 patients (8.6%) were diagnosed to have PFO. Another 23 patients (2.3%) had a hole in the IAS and were diagnosed as having ASD: 21 with an ostium secundum-type ASD and 2 with the sinus venosus type. ASA accompanied ASD in three patients. Electrocardiography-gated CT using the saline-chaser contrast injection technique that is routinely used for coronary arterial imaging can be used to detect interatrial shunts. The technique can also serve as a method for differentiating PFO, ASD, and ASA.

Effect of varying contrast material iodine concentration and injection technique on the conspicuity of hepatocellular carcinoma during 64-section MDCT of patients with cirrhosis

The aim of this study was to compare the intraindividual effects of contrast material with two different iodine concentrations on the conspicuity of hepatocellular carcinoma (HCC) and vascular and hepatic contrast enhancement during multiphasic, 64-section multidetector row CT (MDCT) in patients with cirrhosis using two contrast medium injection techniques. Patients were randomly assigned to one of two groups with an equal iodine dose but different contrast material injection techniques: scheme A, fixed injection duration (25 s), and scheme B, fixed injection flow rate (4 ml s(-1)). For each group, patients were randomised to receive both moderate-concentration contrast medium (MCCM) and high-concentration contrast medium (HCCM) during two CT examinations within 3 months. Enhancement of the aorta, liver and portal vein and the tumour-to-liver contrast-to-noise ratio (CNR) were compared between MCCM and HCCM. 30 patients (mean age 59 years; range 45-80 years; 16 patients in scheme A and 14 in scheme B) with a total of 31 confirmed HCC nodules were prospectively enrolled. For scheme B, the mean contrast enhancement of the aorta and tumour-to-liver CNR were significantly higher with HCCM than with MCCM during the hepatic arterial phase (+350.5 HU vs +301.1 HU, p = 0.001, and +7.5 HU vs +5.5 HU, p = 0.004). For both groups, there was no significant difference between MCCM and HCCM for all other comparisons. For a constant injection flow rate, HCCM significantly improves the conspicuity of HCC lesions and aortic enhancement during the hepatic arterial phase on 64-section MDCT in patients with cirrhosis.

Pancreatic adenocarcinoma: a comparison of automatic bolus tracking and empirical scan delay

To evaluate the efficacy of automatic bolus tracking in multidetector row CT (MDCT) for pancreatic adenocarcinoma as compared with standard scan delay using the fixed duration contrast injection technique. Seventy-nine patients with pancreatic adenocarcinomas underwent three-phase enhanced CT with an individualized scan delay as determined by automatic bolus tracking (protocol 1) or an empiric scan delay (protocol 2). We evaluated enhancement of the aorta, portal vein, hepatic parenchyma, pancreatic parenchyma, and pancreatic adenocarcinoma during each phase. Two radiologists graded the conspicuity of pancreatic adenocarcinoma in the pancreatic parenchymal phase. The results for the different groups were statistically compared. Pancreatic parenchymal enhancement (mean ± standard deviation, 100.2 HU ± 17.6 vs. 88.5 HU ± 22.1; P < 0.05) and tumor-to-pancreas contrast (mean ± standard deviation, 75.3 HU ± 25.0 vs. 63.1 HU ± 24.1; P < 0.05) were significantly greater in protocol 1 than in protocol 2 during pancreatic parenchymal phase. Qualitative results correlated well with quantitative results (reviewer 1: R (s) = 0.78, P < 0.001; reviewer 2: R (s) = 0.66, P < 0.001) The use of automatic bolus tracking with MDCT can significantly improve the degree of contrast enhancement in the pancreatic parenchyma and tumor-to-pancreas conspicuity.