Ml Of Contrast Medium Research Articles

Coronary artery disease and aortic stenosis: small steps to cross the border to full interventional treatment in selected high-risk patients

More than 50% of the 240 patients referred for TAVI had CAD with primarily advanced stages of disease. Most of the patients have already been treated either with PCI or CABG before TAVI. Surprisingly CAD was firstly detected during TAVI evaluation in almost one-third of the patients, whereas the necessity to treat CAD by PCI was limited to only eleven (17%) patients. Despite the higher risk profile of patients with AS and concomitant CAD, the mortality rate at 30 days and follow-up of 248±239 days did not differ respectively. In the study by Wenaweser and Pilgrim, almost two-thirds of the 256 patients had CAD 6 . In contrast to Gautier et al, 35% of the pati- ents received CAD treatment by PCI, 23 patients as staged and 36 patients as concomitant procedure. The DUKE jeopardy score to assess myocardium at risk and the SYNTAX score were used to guide CAD treatment strategy via PCI. There was no significant difference with regard to the VARC safety endpoints between the TAVI and the TAVI+PCI group, as well as for the staged and conco- mitant approach. It has to be underlined that all cause mortality in the PCI group was almost double compared to the TAVI group (10.2% vs. 5.6%) without reaching the level of significance, most likely due to the limited patient number. In this paper, the low rates of significant renal failure stage 3 according to the RIFLE criteria is noticeable given the relatively high amounts of contrast medium used in all groups. Even if the SYNTAX score was comparable, 330±140 mL of contrast medium were used only for PCI in the staged intervention group. It appears that more complex procedures were possibly performed at two different time points. Another inter- pretation might be the operator-dependent cautious use of contrast medium during a concomitant approach.

Accuracy of Intra-Articular Injection of the Glenohumeral Joint: A Modified Anterior Approach

This study examined the accuracy of our modified anterior approach to the glenohumeral joint using arthrography. Two hundred fifty-six consecutive patients with adhesive capsulitis received the glenohumeral joint injection: a mixture of 1 mL of 40 mg of triamcinolone hexacetonide, 2 mL of 2% lidocaine, 3 mL of contrast medium (Ioxitalamate), and 4 mL of normal saline solution, for a total of 10 mL, through a modified anterior approach. Anteroposterior, lateral, and axial arthrography after each injection was performed to determine the accuracy and patterns of the injection. The injection was judged to be successful if some of the contrast medium was placed within the joint. There were 78 male and 178 female patients, and the mean age was 54 years (range, 28 to 87 years). In 232 of the 256 patients (90.6%), the injection was deemed to have reached the glenohumeral joint, and these cases were considered successful. Among these patients, the contrast medium was shown only in the joint in 189 (73.8%), whereas in 43 (16.8%) it was shown both in and out of the joint. Of the 24 misguided injections, 15 (5.9%) had anterior placement, 6 (2.3%) had posterior placement, and 2 (0.8%) had superior placement, whereas the material was located in all portions outside the joint in 1 (0.4%). This study showed that our modified anterior approach had an accuracy greater than 90% for the intra-articular injection of the glenohumeral joint without radiographic guidance.

Body Size-Adapted Dose of Contrast Material and Scanning Protocol in 320-Detector Row CT Coronary Angiography

Because an increase in patient body size produces lower vessel attenuation and higher image noise in computed tomography coronary angiography (CTCA), a protocol in which the dose of contrast material was adapted to the body weight, and tube voltage and current were adapted to the body mass index (BMI) was evaluated. A total of 136 patients who underwent CTCA were assigned to 1 of 2 protocols; the patients received 40 mL of contrast material (A; n = 52), or 0.7 mL/kg of contrast material (B; n = 84). Tube voltage and current were adapted to the BMI. In group A, there was no significant correlation between BMI and image noise (r = -0.21, P = 0.15). However, BMI correlated inversely with contrast-to-noise ratio (CNR; right coronary artery, r = -0.29, P < 0.05; left main coronary artery, r = -0.33, P < 0.05) and image quality score (r = -0.55, P < 0.001). In group B, there was no significant correlation between BMI and image noise (r = -0.14, P = 0.21), CNR (right coronary artery: r = -0.09, P = 0.45; left main coronary artery: r = -0.07, P = 0.55), and image quality score (r = 0.03, P = 0.79). Use of a body size-adapted dose of contrast material and scanning protocol results in similar CNR and image quality independent of individual BMI.

Clinical Implementation of the New MEDRAD XDS Contrast Extravasation Detector for Multidetector Computed Tomography

Background Increased speeds of computed tomography (CT) acquisition and concomitant increased intravenous (IV) bolus injection rates have placed patients at greater risk of contrast extravasation. Purpose To assess the efficacy of the MEDRAD XDS extravasation detector by recording the incidence of contrast extravasation in high-risk patients during CT angiography. Material and Methods We prospectively collected data on 25 adults ages 45 to 85 years (mean=65 years), all of whom were considered to be at high risk of having a contrast extravasation. All patients underwent CT angiography with power-injected IV contrast injection introduced via an antecubital venous line. Details recorded included patient age and weight, contrast volume, flow rate, maximum injector pressure, image quality, and extravasation incidence and volume. The size of the most commonly used cannula was 20 gauge and the flow rates ranged from 4.0 to 6 mL/second. Results The XDS device alerted the clinicians to five episodes of extravasation. These were identified at an early stage of the injection with no more than 8 mL of contrast material having been introduced. Conclusion The utility of this device has been demonstrated and its employment should reduce extravasated contrast volumes with minimum discomfort to high-risk patients.

High incidence of nephropathy in neurosurgical patients after intra-arterial administration of low-osmolar and iso-osmolar contrast media

Percutaneous endovascular examinations and interventions require significant amounts of iodinated contrast media (CM) and have been reported to be complicated by an increased incidence of post-contrast nephropathy. To evaluate renal function, the incidence of post-contrast nephropathy, and risk factors after interventional procedures in neurosurgical patients after intra-arterial administration of a low-osmolar contrast medium (LOCM) versus an iso-osmolar contrast medium (IOCM). This single-center, prospective, randomized, double-blinded study included 92 patients in its final analysis (mean age 49.6 ± 12.6 years, 29.3% men, mean eGFR 97.8 ± 26.3 mL/min/1.73 m(2)). LOCM was used in 48 patients (52.2%) and IOCM in 44 patients (47.8%). The patients were given an average of 151.2 ± 52.1 mL of contrast medium intra-arterially. Serum creatinine (SCr), urinary N-acetyl-β-glucosaminidase (NAG) excretion, and creatinine clearance (CCr) were measured at baseline, and on days 1 and 3 after the procedure. Baseline risk factors, renal functional parameters, and average CM doses were not statistically different between the two groups. SCr, NAG, and CCr values did not differ significantly between the LOCM and IOCM groups on days 1 and 3 after CM administration. Nephropathy developed in 21 cases (22.8%): 13 (27.1%) after LOCM use and 8 (18.2%) after IOCM; (P = NS). The only significant risk factors of CIN were the diabetes (P = 0.0466) and atherosclerosis (P = 0.0498). We found a high incidence of nephropathy in neurosurgical patients after intra-arterial CM administration. The renal function values and incidence of nephropathy following LOCM administration were not statistically different from those following IOCM administration.

Changes of the internal diameter of coronary artery bypass grafts in the postoperative course: Assessment based on X-ray computed tomography

The authors used x-ray computed tomography (x-ray CT) for following up the changes of the internal diameter of coronary artery bypass grafts. After the level of the bifurcation of the truncus pulmonalis had been detected by localizing scans from the ascending aorta to the apex of the left ventricle (scanning time, three seconds; slice thickness, 5 mm) 30 mL of contrast medium was injected at a rate of 3 mL/sec via the antecubital vein. Five scans were obtained consecutively, starting eight seconds after initiation of the contrast medium injection. On the basis of two x-ray CT scans (for ± six and thirty-six ± twenty months after surgery) and a selective graft angiogram (twelve ± fifteen months after surgery), 21 patients (20 men, mean age fifty-five ± eight years) were included with a total of 35 saphenous vein grafts. The findings were compared with intraoperative electromagnetic flow meter measurements.

Computed tomographic anatomy of the equine stifle joint

To provide a detailed computed tomography (CT) reference of the anatomically normal equine stifle joint. Sample-16 hind limbs from 8 equine cadavers; no horses had evidence of orthopedic disease of the stifle joints. CT of the stifle joint was performed on 8 hind limbs. In all limbs, CT was also performed after intra-articular injection of 60 mL of contrast material (150 mg of iodine/mL) in the lateral and medial compartments of the femorotibial joint and 80 mL of contrast material in the femoropatellar joint (CT arthrography). Reformatted CT images in the transverse, parasagittal, and dorsal plane were matched with corresponding anatomic slices of the 8 remaining limbs. The femur, tibia, and patella were clearly visible. The patellar ligaments, common origin of the tendinous portions of the long digital extensor muscle and peroneus tertius muscle, collateral ligaments, tendinous portion of the popliteus muscle, and cranial and caudal cruciate ligaments could also be consistently evaluated. The cruciate ligaments and the meniscotibial ligaments could be completely assessed in the arthrogram sequences. Margins of the meniscofemoral ligament and the lateral and medial femoropatellar ligaments were difficult to visualize on the precontrast and postcontrast images. CT and CT arthrography were used to accurately identify and characterize osseous and soft tissue structures of the equine stifle joint. This technique may be of value when results from other diagnostic imaging techniques are inconclusive. The images provided will serve as a CT reference for the equine stifle joint.

A new method using MRI to delineate areas of head and neck cancer targeted by intra-arterial infusion via a superficial temporal artery

To determine whether anticancer drugs delivered via arterial infusion can permeate entire tumors using a new MRI flow check method. We infused 20 ml of contrast medium (2 ml of Gd-GDPA plus 18 ml of normal saline) over a period of 10 min using a continuous injection pump, then immediately performed MRI using a 1.5 T unit. Images were obtained in 5-mm-thick continuous sections in two or three planes (axial, coronal, and sagittal) depending on the extent of the tumor, and enhanced fast gradient echo 3 D (EFGRE3D) images with a special inversion at lipids were photographed using a neurovascular array coil. The new MRI flow check method delineated an area of tongue cancer perfused with drugs more accurately than conventional methods.The MRI flow check method provides accurate information about areas of arterial infusion.

Stenosis Asymmetry Index (SAI) between symptomatic and asymptomatic patients in the analysis of carotid arteries. A study using CT angiography

Extracranial carotid artery stenosis is accepted as a significant risk factor for cerebrovascular events. The purpose of this paper was to evaluate whether the Stenosis Asymmetry Index (SAI) between carotid arteries (in symptomatic and asymptomatic patients) can be considered a further parameter in the stroke risk stratification. 60 consecutive symptomatic (males 36; median age 64) patients and 60 non symptomatic patients matched for gender and age, were analyzed using a 40-detector-row CT angiography. Each patient was analyzed by injecting 80 mL of contrast material at a 5 mL\s flow rate. Stenosis degree of 240 carotids was calculated according to NASCET method. For each patient, the ratio between the most severe stenosis and the contralateral was calculated to obtain the SAI. Multiple logistic regression analysis was performed and ROC curve was also calculated. Results of our study indicate a mean SAI of 1.48 (± 0.35 SD) in the asymptomatic group and a mean SAI of 1.69 (± 0.53 SD) in the symptomatic group with a statistically significant difference (p value=0.0204). The multiple logistic regression analysis did not find statistically significant association between SAI and symptoms. The ROC curve analysis indicated that an SAI value of 1.8 has a specificity of 84.31% presence of cerebral symptoms whereas using a 1.2 SAI we obtained a sensitivity of 88.24%. Results of our study suggest that a SAI>1.8 has a good sensitivity in identifying the association with cerebrovascular events.

Dual-energy computed tomographic angiography of head and neck with dual-source computed tomography: image quality and radiation dose

To investigate the image quality and radiation dose of dual-energy (DE) computed tomographic angiography (CTA) of head and neck. We retrospectively analyzed two groups of patients (both n=30) undergoing 64-slice spiral CTA of cervical and cranial regions with different scan protocols. The DE group was obtained with 140/80 kVp, 64/272 mAs, 0.6 pitch, 80 ml of contrast medium, and caudal-cranial scan orientation. The single-energy (SE) group was obtained with 120 kVp, 220 mAs, 1.2 pitch, 60 ml of contrast medium and cranial-caudal scan orientation. The image quality and radiation dose were compared. The attenuation values and noises were measured on transverse images at 4 different vessels (the distal part of common carotid artery and adjacent vein in same axial image; the M1 segment of middle cerebral artery and sigmoid sinus or confluence of sinus in same image) and two muscles: erector spinae presenting average soft tissue enhancement and supraspinatus muscle presenting regions of great artifact. In cranial region the arterial enhancement and venous contamination were similar (P=0.1427,P=0.1116) . In cervical region the arterial enhancement was similar (P=0.9414) . DE group had significantly greater venous contamination (P<0.0001) , while the mean attenuation value of common carotid artery was still 127 Hu higher than that of jugular vein. No matter artifact of soft tissue was obvious or not, the noise of DE group was significantly less than that of SE group (both P<0.0001) , and the soft tissue enhancement was similar (P=0.0760,P=0.0793) . The radiation dose required for bone-subtraction angiography was significantly less in DE group than in SE group (P<0.0001) . DE group has comparable image quality to SE group and less scan dose for bone-subtraction. DE-CTA has great potential in clinical application. "

Correlation between dual-phase dynamic multi-detector CT findings and fibrosis within lung adenocarcinoma tumors

We focused on fibrosis within lung adenocarcinoma tumors in order to retrospectively analyze correlations with dual-phase contrast enhanced dynamic CT findings. We evaluated 89 patients with stage I lung adenocarcinoma who underwent dynamic CT scans (80-96 mL of contrast material, 2.5-3 mL/s injection) and tumor resections. Attenuation values of both the early phase (21-37 s after injection) and the delay phase (91-95 s) of enhanced CT minus the baseline plain CT attenuation were calculated as ΔEarly and ΔDelay. An early enhancement ratio was defined as ΔEarly/ΔDelay×100. These enhancement patterns were compared with patient and tumor characteristics, including scar grades that were the degrees of fibrosis within tumors evaluated semi-quantitatively by pathologists. From multivariate analysis, only the tumor scar grade showed significant correlations with ΔEarly (p<0.001) and the early enhancement ratio (p<0.001). For ΔEarly and the early enhancement ratio, there were significant differences among 4 groups based on tumor scar grades (p=0.003 and p=0.006, respectively); a higher scar grade tumor tended to show lower enhancement at the early phase. There was a significant negative correlation between the amount of fibrosis and the enhancement grade at the early phase of contrast enhanced dynamic CT in stage I lung adenocarcinoma. Dynamic CT findings could be modified by the degree of fibrosis within a lung tumor.

Inverse-direction scanning improves the image quality of whole carotid CT angiography with 64-MDCT

The purpose of this prospective study was to clarify whether reducing the incidence of perivenous artifacts through craniocaudal scanning improves the quality of 64-multidetecter computed tomography (MDCT) angiography images of the whole carotid artery. Forty patients underwent MDCT angiography in the caudocranial (n=20) or craniocaudal (n=20) direction in 2007. All patients were injected with 75 ml of contrast media followed by a 35-ml saline chaser bolus at 4.0 ml/s in the right antecubital vein. Maximum intensity projection (MIP) images were scored according to image quality on a scale of 1-5. Bilateral arterial and venous attenuation was measured on 10 separated slices. We compared the mean image quality score of the two groups (i.e. those scanned caudocranially and those scanned craniocaudally). We analyzed the correlation between vascular attenuation and mean image quality. Compared with the caudocranial group, the craniocaudal group had higher image quality scores (median, 3.70 vs. 3.40; 95% CI, 3.50-3.96 vs. 3.06-3.60; p<0.05), higher arterial attenuation (median, 550 HU vs. 489 HU; range, 270-686 vs. 302-574; p<0.05), and lower maximum venous attenuation (median, 436 vs. 1452 HU; range, 250-617 vs. 377-2044; p<0.01). Multiple regression analysis revealed that the most significant correlation factor with image quality was minimum arterial attenuation (R2=0.42, p<0.001) measured near the brachiocephalic artery. In the caudocranial group only, there was a negative correlation between right brachiocephalic venous attenuation and minimum arterial attenuation. Compared with conventional caudocranial scanning, craniocaudal scanning improves the image quality of 64-MDCT angiography images of the whole carotid artery.

Renal Embolization and Nephrectomy in a Single Surgical Act in High-Risk Renal Tumor Pathology

Renal artery embolization is a procedure that has been shown to be useful as a concomitant treatment for the resection of large renal tumors. Over the years, preoperative renal artery embolization concomitant with nephrectomy as a treatment option has proved to be useful in reducing morbi-mortality rates; however this procedure is not exempt from significant iatrogenia. Performing this technique in conjunction with nephrectomy in a single surgical act helps to maintain the advantages of this treatment, which in turn considerably reduces the associated morbi-mortality rates. This study presents seven patients selected by the Urology Service in a nonconsecutive manner who underwent renal artery embolization concomitant with nephrectomy in a single surgical procedure for large renal tumors, thus presenting a variation to the usual techniques to improve and simplify the procedure. General data were obtained from all patients including age, gender, characteristics of the tumor, and symptomatology at the time of diagnosis. For all the cases, use of resources was analyzed in terms of duration of surgery, the amount of iodinated contrast medium used during the embolization procedure, and the mean duration of hospital and intensive care unit stay. Complications were evaluated with respect to general morbi-mortality associated with the complete procedure, hematic losses during the procedure, transfusion requirements, and renal function (calculated by measuring preoperative and 48-hour postoperative serum creatinine levels). All patients reported having symptoms at the time of diagnosis, all of them had tumors measuring >13cm in diameter (major). In all the cases, 100% technical success was obtained with the embolization and nephrectomy. The mean duration of surgery in the case of embolization with coils was 45 minutes, and 25 minutes in the case of embolization with Amplatzer. Amean volume of 115 mL of contrast medium was used in the case of embolization with coils, whereas for the other cases, a mean volume of 71 mL of iodinated contrast was used. Among all the patients, only two of them required to be cared at the intensive care unit during 24 hours. On an average, reported blood loss was 380 mL. During the procedure, two patients (28.6%) required a transfusion of two units of red cells. No cases of perioperative or postoperative mortality were reported. With respect to morbidity, only one patient (14.3%) experienced a complication in the form of a superficial infection of the surgical wound, which was later resolved by antibiotic therapy. One patient (14.3%) presented a slightly higher preintervention level of creatinine (1.42). Two patients (28.6%), both of whom underwent embolization by using coils, experienced deterioration of postoperative renal function. Preoperative embolization of the renal artery as a coadjuvant treatment option in high-risk renal neoplasia has clear technical benefits for the subsequent nephrectomy and also medical benefits for the patients. Performing both the procedures concomitantly as a single surgical act seems to retain the advantages of the embolization procedure, by reducing mortality rates and producing little associated morbidity. Technically, embolization with Amplatzer plugs seems to be faster and easier as compared with embolization with coils.

Establishment of temporomandibular joint puncture technique in rats usingin vivomicro-computed tomography (R_mCT®)

The aim of the report was to establish puncture techniques for the temporomandibular joint (TMJ) cavity in rats. The experimental sample comprised 30 male Sprague-Dawley rats. Under general anaesthesia the superior joint cavity of the rat was punctured either laterally (lateral puncture technique (LPT), n = 11), anteriorly (anterosuperior puncture technique (ASPT), n = 13) or anteroinferior puncture technique (AIPT), n = 6) using a 27-gauge needle. After the tip of the needle was confirmed by micro-CT (R-mCT®, Rigaku, Tokyo, Japan) located on the mandibular fossa, 0.05 ml of contrast media was injected under micro-CT fluoroscopic guidance. After confirmation that the joint cavity was filled with contrast media, micro-CT imaging was carried out. The puncture for LPT was accurate in 5 of the 11 animals. The ASPT was accurate in all 13 animals. The AIPT punctured 3 of the 6 animals. Furthermore, the ASPT and AIPT demonstrated improved preservation of the needle; it was harder to detach the needle, which led to greater stability. These results suggest that ASPT assisted by R-mCT® is useful for basic research, including drug discovery and pathogenesis of TMJ diseases.

Combined Assessment of Aortic Root Anatomy and Aortoiliac Vasculature With Dual-Source CT as a Screening Tool in Patients Evaluated for Transcatheter Aortic Valve Implantation

The objective of our study was to investigate the feasibility, image quality, and clinical implications of a combined dual-source CT angiography (CTA) protocol to assess aortic root anatomy and aortoiliac vasculature in patients with severe aortic stenosis evaluated for transcatheter aortic valve implantation. Eighty consecutive patients (47 women and 33 men; mean age, 82.3 ± 7.8 [SD] years) with severe aortic stenosis evaluated for transcatheter aortic valve implantation underwent a combined single-dose contrast-enhanced dual-source CTA protocol (body weight < 70 kg, 110 mL of contrast medium; ≥ 70 kg, 130 mL) consisting of ECG-gated dual-source CTA of the chest with integrated cardiac CT and ungated CTA of the abdomen and pelvis. Two independent observers measured the dimensions of the aortic root and the aortoiliac vasculature and rated image quality semiquantitatively. Vessel attenuation was assessed. Amenability to transfemoral access was evaluated on the basis of vessel diameter (> 7 mm), anatomy, and the presence of vascular disease. Image quality of the aortic root was diagnostic in all 80 patients, and image quality of the aortoiliac vasculature was diagnostic in 79 patients. Vascular attenuation was greater than 200 HU at any vessel level. The mean diameter of the aortic annulus was 24.1 ± 2.9 (SD) mm. Inter- and intraobserver correlations for aortic root and aortoiliac measurements were high (r = 0.93-0.99). Aortic root dimensions were suitable for transcatheter aortic valve implantation in 65 patients (81%). Thirty-eight patients (48%) were deemed amenable to instant transfemoral access without another vasculature intervention. The dimensions of the aortic root and the aortoiliac vasculature can be assessed with a combined single-dose contrast-enhanced dual-source CTA protocol, thereby allowing determination of patient eligibility for transcatheter aortic valve implantation, prosthesis sizing, and evaluation of the access route in one examination.

Contrast Opacification Using a Reduced Volume of Iodinated Contrast Material and Low Peak Kilovoltage in Pulmonary CT Angiography: Objective and Subjective Evaluation

The purpose of our study was to evaluate whether a reduced volume of iodinated contrast material for pulmonary CT angiography (CTA) using a low peak kilovoltage (kVp) technique yields equivalent opacification in all vessels. Four hundred fifty-two consecutive pulmonary CTA patients (265 women and 187 men; age range, 18-91 years; mean age, 56.2 years) were retrospectively evaluated. Patients were grouped into those receiving 125 mL (n = 229) and 75 mL (n = 223) of 370 mg I/mL iodinated contrast material. Low kVp was used in all patients. Hounsfield units were measured at lobar, posterobasal segment, posterobasal ramus, and medial basal subsegmental ramus in the left lower lobe. Three thoracic radiologists blinded to contrast dose independently and randomly evaluated the quality of enhancement using a 3-point scale at the same levels. The two-sample Student's t test was used to compare contrast opacification between groups; Spearman's correlation and the C-statistic were used to assess objective and subjective measurements. Interreader agreement was measured using Kendall's coefficient. Mean contrast opacification differences between 125 mL versus 75 mL were not statistically significant (p > 0.21) at the lobar, segmental, and posterior basal rami, although the mean trended (p = 0.07) toward higher opacification of the medial basal ramus among 75 mL patients. Across all four pulmonary artery segments, there was good concordance between subjective and objective measurements, significantly higher than the null value of 0.50 (p > 0.05). For subsegmental arteries, concordance between objective and subjective measures was greater for the 75 mL group (p < 0.05). There was good interreader concordance, with a concordance coefficient of 0.70 (95% CI, 0.66-0.74). Both objective and subjective measures of contrast opacification support a reduction from 125 to 75 mL of contrast medium required for pulmonary CTA.

Multidetector computed tomography venography: optimum dose of contrast material

The aim of this study was to determine the optimum dose of contrast material for evaluating veins in the lower limbs. A total of 134 patients who underwent multidetector computed tomography (MDCT) due to suspected deep vein thrombosis (DVT) or pulmonary embolism (PE) were included in this study. One hundred milliliters of iopamidol 100 ml, with 370 mg I/ml was administered. The degree of contrast enhancement of veins in the lower limbs was classified on a 4-point scale (grade 1, poor --> 4, excellent). Regions of interest (ROIs) were positioned in the femoral vein and the popliteal vein to measure CT numbers in these veins. Correlations between the CT number in each ROI and body weight were examined. The mean +/- SD body weights of patients by contrast-enhancement grade were as follows: grade 1, 86.3 +/- 10.2 kg; grade 2, 72.6 +/- 10.7 kg; grade 3, 59.7 +/- 8.7 kg; grade 4, 51.3 +/- 7.9 kg. Negative correlations were found between body weight and CT number for both the femoral vein and the popliteal vein. Grade 3 or better contrast enhancement was obtained in 79 of 81 patients (97.5%) weighing <60 kg. For patients weighing <60 kg, 100 ml of contrast material (370 mg I/ml) is considered sufficient for evaluating veins in the lower limbs.

Kidney and Urinary Tract Imaging: Triple-Bolus Multidetector CT Urography as a One-Stop Shop—Protocol Design, Opacification, and Image Quality Analysis

To retrospectively evaluate renal, vascular, and urinary tract visualization following a single postcontrast multidetector computed tomographic (CT) urographic sequence performed with three limited-volume bolus injections. The institutional review board approved this retrospective study. Patient informed consent was waived. Triple-bolus multidetector CT urography was performed in 110 patients. Triple-bolus protocol consisted of 30 mL of contrast material at 2 mL/sec at 0 seconds, 50 mL at 1.5 mL/sec at 435 seconds, 65 mL at 3 mL/sec at 488 seconds, with total abdominal scanning time of 510 seconds. Two independent readers rated urinary tract opacification and qualitatively and quantitatively assessed renal parenchymal and vascular contrast enhancement. Upper urinary tract (UUT) distention was measured by one reader. Interobserver agreement was assessed by using kappa statistics. Complete opacification of the intrarenal collecting system and proximal ureter was achieved in 91% (184 of 202) (kappa = 0.62) and 82% (166 of 202) (kappa = 0.94) of segments, respectively. The distal ureter was not opacified in 21% of the cases (kappa = 0.92), and the bladder was not opacified in 20% of the cases. Mean distention was higher for proximal (3.9 mm) than for distal (3.7 mm) segments. Image quality of renal parenchymal enhancement was excellent in 76% of cases. Arteries showed better contrast enhancement than veins (excellent rating in 89% vs 59% of the cases). Radiation dose calculated for triple-bolus acquisition was 9.8 mSv. Triple-bolus multidetector CT urography is a dose-efficient protocol acquiring corticomedullary-nephrographic-excretory and vascular enhancement phases in a single acquisition and provides sufficient opacification and distention of the UUT. Simultaneously, adequate image quality of renal parenchyma and vascular anatomy is achieved.

Saving Dose in Triple-Rule-Out Computed Tomography Examination Using a High-Pitch Dual Spiral Technique

High radiation doses remain a drawback of current triple-rule-out computed tomography (CT) protocols. With dual source CT, a new high-pitch dual spiral technique offers the possibility to acquire an Electrocardiography (ECG)-gated-synchronized dataset of the whole chest in less than 1 second. The aim of this study was to compare the dose of such a protocol to a standard, nongated chest scan and to a conventional, retrospectively ECG-gated triple-rule-out protocol. Also, the efficacy and dose of this dual spiral protocol was to be compared in patients examined with this high-pitch technique and matched controls scanned with the conventional technique. An anthropomorphic Alderson Rando phantom was equipped with thermoluminescent detectors and scanned with the high-pitch protocol (Siemens Somatom Definition Flash; 2 x 120 kVp, 426 mAseff, 128 x 0.6 mm collimation, pitch 3.2), the nongated chest scan (same scanner; 120 kVp, 160 mAseff, 128 x 0.6 mm, pitch 1.2; equivalent Computed Tomography Dose Index (CTDI) of 7.12 mGy), and the conventional gating technique (Siemens Somatom Definition; 120 kVp, 560 mAseff with ECG pulsing interval at 30%-70% of the R-R cycle, 64 x 0.6 mm, pitch 0.3). Noise was measured in air, central and peripheral soft tissue of the phantom. Conversion factors were determined based on the measured dose and the dose-length products of the scanner. The protocol was then applied with ethics committee approval in 31 patients suffering from acute chest pain. The 120 mL of contrast material (Ultravist 370, Bayer Schering Pharma) was applied at 5 mL/s. Dose was calculated based on the dose-length products and the conversion factor. Image quality was assessed by 2 readers for aorta, pulmonary arteries, and coronary arteries. The results were compared with matched controls scanned with the conventional ECG gating technique and non-ECG gated thorax scans. The dose determined with thermoluminescent dosimeters measurements amounted to 2.65, 2.68, and 19.27 mSv, respectively, for the dual spiral technique, the standard chest scan, and the conventional retrospective technique. There was no significant difference in image noise. Respective conversion factors were 0.0186, 0.0188, and 0.0180 mSv/mGy x cm. In the patient examinations, dose was 4.08 +/- 0.81 mSv with the high-pitch protocol compared with 20.4 +/- 5.3 mSv in the matched controls with the conventional technique, and 4.40 +/- 0.83 mSv for the non-ECG gated thorax scan. Scan times were 0.7 +/- 0.1 seconds for the high-pitch scan and 15 +/- 3 seconds for the conventional chest pain scan. Aorta and pulmonary arteries were depicted in diagnostic quality in both groups. About 84.7% of coronary artery segments were rated as diagnostic in the high-pitch exams (95.4% below 65 bpm and only 72.8% in higher heart rates), whereas 92.9% were diagnostic with the conventional approach. The high-pitch dual spiral technique requires only about one-fifth of the dose of conventional ECG gated triple-rule-out protocols, thus matching that of a standard nongated chest scan. With less than 1 second, the scan time is very short. This protocol can be recommended for patients with unclear chest pain with rhythmic heart rates below 65 bpm.

Diagnostic imaging of traumatic pseudoaneurysm of the thoracic aorta

BackgroundThe purpose of the study was the presentation of findings and diagnostic imaging in patients with traumatic pseudoaneurysms of the thoracic aorta, as a rare consequence of road traffic accidents.Patients and methodsIn 22 years we have found 8 traumatic pseudoaneurysms of the thoracic aorta, out of which 7 (87.5%) in male and 1 (12.5%) in female patients. At the time of accidents the youngest patient was 21 and the oldest was 55 (mean age 33.8 years), and at the moment of diagnosing a pseudoaneurysm they were 26 and 55 years old, respectively (mean age 38.7 years). In all patients chest radiography was performed as well as CT scan, in 6 (75%) patients intra-venous digital subtraction angiography was performed (i.v. DSA) and in 1 (12.5%) MRI. CT was performed with the application of 120 ml, and i.v. DSA with 60 ml of contrast medium, respectively.ResultsIn 8 (100%) patients, who suffered a road traffic accident, and whose chest radiograph showed the enlargement of the aortic knob and widening of the mediastinum, CT, i.v. DSA and MRI revealed a traumatic pseudoaneurysm of the thoracic aorta. Periods of time between the accidents and the initial diagnosis of the pseudoaneurysm varied from 7 days to 18 years (median 2.0 years). The diameter of the pseudoaneurysm was from 4.5 to 9.2 cm (median 5.5 cm). In 7 (87.5%) isthmus was involved, and in 1 (12.5%) descending thoracic aorta, respectively. The chest radiograph revealed marginal calcifications in 4 (50%), and on the CT in 5 (62.5%) patients. Intraluminal thrombosis was found by CT in 2(25%) traumatized patients.ConclusionsTraumatic pseudoaneurysm should be taken into consideration in blunt chest trauma, where a chest radiograph shows suspicious regions. A multislice CT is a diagnostic method of choice.