mL Of Nonionic Contrast Material Research Articles

Radiological Arterial Anatomy in Mature Microminipigs as a Pre-clinical Research Model in Interventional Radiology.

To define the radiological arterial anatomy in mature microminipigs as a pre-clinical research animal model in interventional radiology. Five female microminipigs (weighing 20.9 ± 2.9kg) were used in this study. Under general anesthesia, computed tomography (CT) angiography was performed using a 16-slice CT scanner. CT was performed 12s after initiation of an intravenous injection of 40ml of nonionic contrast media at 3.0ml/second using a power injector. The transverse CT angiography images were evaluated using a digital imaging and communication in medicine viewer, and the diameters of the following 41 arteries were measured.: ascending aorta, descending aorta, thoracoabdominal aorta, abdominal aorta, pulmonary artery trunk, both pulmonary, brachiocephalic artery, short common bicarotid, both common carotid artery, subclavian, bronchial, internal mammary, celiac, common hepatic, left lateral hepatic, middle hepatic, left hepatic, gastroduodenal, cranial duodenopancreatic, splenic, left gastric, cranial mesenteric, ileocolic , bilateral colic artery, caudal mesenteric, cranial rectal, renal, both external iliac arteries, internal iliac common trunk, and both internal iliac and femoral arteries. The microminipigs' vascular anatomy was the same as domestic pig anatomy and similar to human anatomy. The diameter of the aorta (ascending to abdominal) was 17.1-7.0mm, iliac and femoral arteries (internal iliac common trunk to femoral artery): 5.5-3.8mm, pulmonary arteries: 9.3-14.7mm, and major first aortic branches (e.g., celiac or brachiocephalic artery): 2.2-9.2mm. This study defined the microminipig arterial anatomy in the trunk.

Comparison of Intravascular Injection Rate Between Blunt and Sharp Needles During Cervical Transforaminal Epidural Block

Background: Cervical transforaminal epidural block (CTEB) is a useful option in the diagnosis and treatment of cervical radicular pain. However, inadvertent intravascular injection can lead to severe neurologic complications. Blunt needles are considered to displace instead of penetrate vessels because of their dull needle tip. Objectives: To investigate whether there is a difference between blunt and sharp needles in intravascular injection rates during CTEB. Study Design: Prospective, randomized, clinical trial. Setting: A tertiary hospital in South Korea. Methods: After institutional review board approval, 108 patients undergoing CTEB for treatment of radicular pain resulting from spinal stenosis and herniated nucleus pulposus were randomly assigned to one of 2 needle groups (blunt needle or sharp needle). The needle position was confirmed using biplanar fluoroscopy, and 2 mL of nonionic contrast medium was injected to detect intravascular injection. Intravascular injection was defined as the contrast medium spreading out through the vascular channel during injection under realtime fluoroscopy. This study was registered in ClinicalTrials.gov. Results: The intravascular injection rate was not significantly different between the blunt needle and sharp needle groups (35.2% vs. 33.3%, P > 0.05). The procedure time was longer in the blunt needle group than in the sharp needle group (101.00 ± 12.4 seconds vs. 56.67 ± 8.3 seconds, P < 0.001). Limitations: This was a single-center study. Additionally, the physicians could not be blinded to the type of needle used. Conclusions: In the present study, use of a blunt needle did not reduce the rate of intravascular injection during CTEB compared to use of a sharp needle. In addition, procedure time significantly increased with blunt needle use compared to sharp needle use. Key words: Analgesia, bleeding, blunt needle, cervical spine, clinical trials, complications, intravascular injection, radiculopathy, sharp needle, transforaminal epidural block

Digital subtraction angiography vs. real-time fluoroscopy for detection of intravascular injection during transforaminal epidural block.

BackgroundTransforaminal epidural block (TFEB) is an effective treatment option for radicular pain. To reduce complications from intravascular injection during TFEB, use of imaging modalities such as real-time fluoroscopy (RTF) or digital subtraction angiography (DSA) has been recommended. In this study, we investigated whether DSA improved the detection of intravascular injection during TFEB at the whole spine level compared to RTF.MethodsWe prospectively examined 316 patients who underwent TFEB. After confirmation of final needle position using biplanar fluoroscopy, 2 mL of nonionic contrast medium was injected at a rate of 0.5 mL/s under RTF; 30 s later, 2 mL of nonionic contrast medium was injected at a rate of 0.5 mL/s under DSA.ResultsThirty-six intravascular injections were detected for an overall rate of 11.4% using RTF, with 45 detected for a rate of 14.2% using DSA. The detection rate using DSA was statistically different from that using RTF (p=0.004). DSA detected a significantly higher proportion of intravascular injections at the cervical level than at the thoracic (p=0.009) and lumbar (p=0.011) levels.ConclusionDuring TFEB at the whole spine level, DSA was better than RTF for the detection of intravascular injection. Special attention is advised for cervical TFEB, because of a significantly higher intravascular injection rate at this level than at other levels.

Diagnostic Accuracy of Multidetector Computed Tomography in Detection of Esophageal Varices.

ObjectiveTo determine the diagnostic accuracy of multidetector computed tomography (MDCT) in the detection of esophageal varices by taking endoscopy as the reference standard.Materials and methodsThis was a cross-sectional prospective study conducted at the Department of Radiology, Aga Khan University Hospital, (AKUH) Karachi, for the duration of 12 months from August 1, 2014 to July 31, 2015. One hundred ninety-six patients with a suspicion of chronic liver disease/cirrhosis undergoing 64 slice MDCT were enrolled in our study and underwent computed tomography (CT) scanning in the Department of Radiology at AKUH. Biphasic CT was performed with images obtained during the hepatic arterial phase (30-second delay) and the portal venous phase (65-second delay) after the intravenous (IV) injection of 120 mL of nonionic contrast material at a rate of 3.5 mL/s. The presence of esophageal varices was evaluated on MDCT with endoscopy as gold standard. The sensitivity, specificity, negative predictive value and positive predictive value, and accuracy of MDCT were assessed against the gold standard.ResultsOur results yielded an MDCT sensitivity of 98.96%, specificity of 100%, positive predictive value (PPV) of 100%, negative predictive value (NPV) of 66.67%, and diagnostic accuracy of 98.97% for esophageal varices in chronic liver disease (CLD) patients.ConclusionThe rate of detection of esophageal varices in patients with chronic liver disease on MDCT in our country is comparable to the international data and we advocate that MDCT should be used as a screening tool in patients with chronic liver disease to exclude esophageal varices.

Clinical Impact of Radioguided Localization in the Treatment of Solitary Pulmonary Nodule

Incidental solitary pulmonary nodules (SPNs) have become an increasingly common CT finding worldwide. Although there are currently many imaging strategies for evaluating SPNs, the differential diagnosis and management of SPNs remains complex because of overlap between benign and malignant processes. Moreover, transbronchial or percutaneous CT-guided biopsies do not always allow definitive diagnoses. In such cases, video-assisted thoracic surgery (VATS) has become the preferred surgical procedure for diagnosis and, in selected cases, for treatment of indeterminate SPNs. The difficulties in localizing smaller, deeper, and ground-glass nodules have been approached with different techniques. The aim of this study was to report 20 years of experience with radioguided thoracoscopic resection of SPNs at the Regional Centre of Nuclear Medicine of Pisa. Three hundred ninety-five patients with SPNs less than 2 cm and deeper than 5 mm below the visceral pleura underwent CT-guided injection of a suspension composed of 0.1 to 0.2 mL Tc-labeled human albumin macroaggregates (Tc-MAA) and of 0.2 to 0.3 mL of nonionic contrast medium into or adjacent to the SPN. During VATS, the pulmonary area with the highest target/background ratio identified by an 11-mm-diameter collimated thoracoscopic gamma probe was resected. From 1997 to 2016, approximately 395 patients with SPN underwent VATS wedge resection using the radioguided technique. Mean SPN size was 13 mm (range, 5-20 mm) with mean distance of 15 mm (range, 6-39 mm) from the visceral pleura. Mean VATS procedural time was 40 minutes (range, 20-90 minutes), with an average time of 3 minutes (range, 1-5 minutes) to localize the nodule. Neither mortality nor major perioperative complication was reported. The success rate of VATS with radioguidance in our series was 99%. Histological examination revealed 206 benign lesions (52%), 59 primary lung tumors (15%), and 130 metastatic nodules (33%). This study demonstrates that radioguided SPN localization by VATS is a feasible, safe, and rapid procedure with highly successful rate of SPN resection.

Detection of Intravascular Injection During Cervical Transforaminal Epidural Injection: A Comparison of Digital Subtraction Angiography and Real Time Fluoroscopy

Background: Transforaminal epidural injection (TFEI) with local anesthetics and steroids are effective in treating spinal radicular pain. However, inadvertent intravascular injection can lead to severe neurologic complications. To reduce complications of intravascular injection, use of imaging modality, such as real-time fluoroscopy (RTF) or digital subtraction angiography (DSA), has been recommended. DSA is an imaging technique that can clearly visualize the blood vessels from surrounding bones or dense soft tissues by subtracting the pre-contrast image from the image after injecting contrast medium. Objective: In this study, we investigated whether there is a difference between RTF and DSA in the detection of intravascular injection during cervical TFEI. Study Design: Clinical study. Setting: Pain clinic in South Korea. Methods: We prospectively examined 137 cervical TFEIs on 128 patients who have a radiating pain from spinal stenosis and herniated nucleus pulposus. The needle position was confirmed using biplanar fluoroscopy and 2 mL of nonionic contrast medium was injected at the rate of 0.5 mL/sec under RTF. Thirty seconds later, 2 mL of nonionic contrast medium was injected at the rate of 0.5 mL/sec under DSA. Intravascular injection was defined as contrast medium spreading throughout the vascular channel during injection of contrast medium under RTF and DSA. This study is registered in the ClinicalTrials.gov (NCT03040648). Results: The detection rate of intravascular injection in RTF was not statistically different compared to that in DSA (30.7 % vs. 34.3%, P > 0.05). Limitations: We injected 2 mL of contrast medium at the rate of 0.5 mL/sec. Further studies about the ideal injection speed and volume of contrast medium for improvement of detection of intravascular injection during TFEI are needed. This study was a single center study. Therefore, multi-center studies are needed to obtain the high level of evidence. Additionally, the procedural pain physician was not blinded to the type of imaging modality, such as RTF and DSA, to detect intravascular injection. To minimize this confirmation bias and provide homogenous procedural conditions for TFEI, the same procedural physician performed all 137 injections. Conclusions: In this study, there is no significant difference in detection rate of intravascular injection between RTF and DSA during cervical TFEI. Key words: Analgesia, bleeding, clinical trials, complications, diagnostic equipment, epidural, radiculopathy, spine

Transient global amnesia after epiduroscopy in a failed back surgery syndrome patient: Case report

Epiduroscopy (EDS) allows diagnosis and treatment of spinal nerve root pathology by a fiberoptic device inserted percutaneously in the epidural space. Transient global amnesia syndrome (TGA) is defined by an abrupt onset of an anterograde and retrograde amnesia that lasts up to 24 h, although mild subclinical neuropsychological deficits, with concomitant vegetative symptoms, can last for days after the episode. To our knowledge no cases of TGA in association with EDS have been recognized. We present a case of a 54-year-old man who was admitted for EDS, having experienced two times the failed surgery for spinal and left leg pain. During the EDS, 10 ml of non-ionic contrast media (CM) was injected to confirm the inside lesions. The epidural adhesions were gently broken down and drugs were injected around any inflamed nerve roots. Immediately after EDS, the patient experienced a TGA with loss of memory for the recent procedure and an impaired ability to retain new information. There were no signs of confusion or altered conscious level or seizure activities and neurological examination was normal. At 24 h a cranial computerized tomography (cCT) without CM showed “abnormal contrast enhancement at subarachnoid liquoral spaces levels”, then at 72 h cCT control was normal. The patient was discharged on the seventh day with perioperative lacunar amnesia persisting at this time. Herein, we sought a possible relationship between neurotoxic effect of CM and TGA in a patient emotionally stressed, even if the CM dose was given as a normal clinical range.

Injectate Volumes Needed to Reach Specific Landmarks and Contrast Pattern in Kambin's Triangle Approach with Spinal Stenosis

ObjectiveTo identify the volumes of contrast material needed to reach the specific landmarks and contrast pattern during Kambin's triangle approach (KB-A) in lumbar spinal stenosis.MethodSixty patients undergoing KB-A were investigated. Fifty-six patients were included in this study. KB-A were performed with the use of contrast-enhanced fluoroscopic visualization. After confirming the appropriate spinal needle position, a slow injection of up to 5.0 ml of nonionic contrast material was carried out. Under intermittent fluoroscopic guidance, contrast volumes were recorded as flow reached specific anatomic landmarks: ipsilateral inferior or superior neural foramen.ResultsAfter 2.0 ml of contrast was injected, 93.2% of KB-A cases spread to the medial aspect of the inferior pedicle of the corresponding level of injection and 86.3% of KB-A spread to the medial aspect of the superior pedicle of the corresponding level of injection. After 3 ml of contrast was injected, 95.3% of KB-A spread to cover both the medial aspect of the inferior pedicle and the superior pedicle of the corresponding level of injection. A volume of 2 ml of injectate reaches the anterior epidural space 100% of the time.ConclusionThis study demonstrates injectate volumes needed to reach the specific anatomic landmarks in KB-A. A volume of 3.0 ml of injectate reaches both the medial aspect of theinferior pedicle and the superior pedicle 94.6% of the time. Therefore, Interventionalists may consider a 1-level instead of a 2-level injection for patients with a bleeding risk or for 2 level central pathology.

Injectate Volumes Needed to Reach Specific Landmarks in Lumbar Transforaminal Epidural Injections

To identify the volumes of contrast material needed to reach specific landmarks during lumbar transforaminal epidural injections (L-TFEIs). Prospective, nonrandomized, observational human study. Academic/private pain management practice. Sixty-nine patients undergoing L-TFEIs were investigated. Sixty patients were included in this study. L-TFEIs were performed with the use of contrast-enhanced fluoroscopic visualization. After the appropriate spinal needle position was confirmed, up to 5.0 mL of nonionic contrast material was slowly injected. Under biplanar fluoroscopic guidance, contrast volumes were recorded as flow reached specific anatomic landmarks: ipsilateral neural foramen, ipsilateral disks superior and inferior to the injected level, and across the midline of the spinous process. After 1.1 mL of contrast was injected, 100% of L-TFEIs spread to the medial aspect of the superior pedicle (PED) of the corresponding level of injection. After 2.8 mL of contrast was injected, 95% of L-TFEIs spread to the superior aspect of the superior intervertebral disk (IVD) of the corresponding level of injection. After 3.6 mL of contrast was injected, 95% of L-TFEIs spread to the inferior aspect of the inferior IVD of the corresponding level of injection. After 3 mL of contrast was injected, 88% of L-TFEIs spread to cover both the superior and inferior IVDs of the corresponding level of injection. After 4 mL of contrast was injected, 93% of L-TFEIs spread to cover both the superior and inferior IVDs of the corresponding injection. After 4 ml of contrast was injected, 55% of L-TFEIs spread beyond the midline of the spinous process, but barely. This study demonstrates injectate volumes needed to reach specific anatomic landmarks in L-TFEIs. A volume of 4.0 mL of injectate reaches both the superior aspect of the superior IVD and the inferior aspect of the inferior IVD 93% of the time.

ECHO-COLOR DOPPLER, MAGNETIC RESONANCE ANGIOGRAPHY AND COMPUTED TOMOGRAPHY ANGIOGRAPHY: WHAT IS THE BEST TECHNIQUE TO CHARACTERIZE RENAL ARTERY STENOSIS?: PP.18.209

Purpose: Renal artery stenosis represents the narrowing of the main renal artery that supplies the kidney. Depending on the degree of stenosis, patients can develop hypertension. Our purpose was to compare the role and the diagnostic efficacy of Echo-Color Doppler (ECD), Magnetic Resonance Angiography (MRA) and Multi-Detector-Row CT angiography (MDCTA) in the study of patients with renal artery stenosis (RAS). Materials and Methods: 11 patients (6 males; 5 females, mean age: 49 years) for a total of 22 renal arteries were analysed by using ECD MDCTA and MRA. The following features were analysed: presence or absence of stenosis, stenosis position (ostial, proximal, central, distal, braches) and the degree of the stenosis. CT scans were obtained after intravenous bolus administration of 110–140 mL of non-ionic contrast material using a 3–6 mL/sec flow rate. We assessed every patient by using axial scans, multiplanar reconstruction (MPR), maximum intensity projection (MIP) and volume rendering (VR) techniques. MRA were performed by using a superconducting 1.5 Tesla Magnet. ECD exams were performed by using a dedicated system with a 11 Mhz probe. Results: USECD detected 3 RSA, MRA detected 4 RAS and MDCTA detected 6 RAS The highest number of stenosis found in the ostial localization (p < 0.001). Conclusions: MDCTA is an highly accurate technique to asses renal artery stenosis. Our data underlined that the site where the radiologist has to look for detect RAS is in ostial position. MRA and ECD determine suboptimal results.

Doxorubicin-Loaded QuadraSphere Microspheres: Plasma Pharmacokinetics and Intratumoral Drug Concentration in an Animal Model of Liver Cancer

The purpose of this study was to evaluate, in vitro and in vivo, doxorubicin-loaded poly (vinyl alcohol-sodium acrylate) copolymer microspheres [QuadraSphere microspheres (QSMs)] for transcatheter arterial delivery in an animal model of liver cancer. Doxorubicin loading efficiency and release profile were first tested in vitro. In vivo, 15 rabbits, implanted with a Vx-2 tumor in the liver, were divided into three groups of five rabbits each, based on the time of euthanasia. Twenty-five milligrams of QSMs was diluted in 10 ml of a 10 mg/ml doxorubicin solution and 10 ml of nonionic contrast medium for a total volume of 20 ml. One milliliter of a drug-loaded QSM solution containing 5 mg of doxorubicin was injected into the tumor feeding artery. Plasma doxorubicin and doxorubicinol concentrations, and intratumoral and peritumoral doxorubicin tissue concentrations, were measured. Tumor specimens were pathologically evaluated to record tumor necrosis. As a control, one animal was blandly embolized with plain QSMs in each group. In vitro testing of QSM doxorubicin loadability and release over time showed 82-94% doxorubicin loadability within 2 h and 6% release within the first 6 h after loading, followed by a slow release pattern. In vivo, the doxorubicin plasma concentration declined at 40 min. The peak doxorubicin intratumoral concentration was observed at 3 days and remained detectable till the study's end point (7 days). Mean percentage tumor cell death in the doxorubicin QSM group was 90% at 7 days and 60% in the bland QSM embolization group. In conclusion, QSMs can be efficiently loaded with doxorubicin. Initial experiments with doxorubicin-loaded QSMs show a safe pharmacokinetic profile and effective tumor killing in an animal model of liver cancer.

Comparison of multidetector CT with F-18-FDG-PET and SPECT in the assessment of myocardial viability in patients with myocardial infarction: A preliminary study

Objective To evaluate the ability of MDCT to detect a nonviable myocardium in patients with myocardial infarction (MI). Methods and material This study included 17 patients with MI in the acute ( n = 13) or chronic stage ( n = 4). MDCT, SPECT, and F-18-FDG-PET were performed in 10 patients during the acute stage and in 2 during the chronic stage of MI. MDCT and SPECT were performed in 13 patients with acute stage and in 4 with chronic stage of MI. Sixteen-slice MDCT was performed 10 min after injection of 120 mL of nonionic contrast media. MDCT, SPECT and PET images were analyzed using a 17-segment model. The depth of hyperenhancement >2/3 was defined as nonviable at MDCT. Results MDCT and SPECT were concordant in localizing the MI in 84.2% (272/323 segments) and were discordant in 15.8% (51/323). MDCT and PET were concordant in localizing MI in 89.2% (182/204) and discordant in 10.8% (22/204). The sensitivity, specificity and diagnostic accuracy of MDCT in determining the nonviable segments were 70.4%, 85.3%, 81.4% as compared with PET, respectively, and 69.4%, 81.8%, 79.9% compared with SPECT, respectively, and 73.5%, 79.4%, 78.4% compared with combined PET and SPECT, respectively. MDCT findings suggested nonviability in additional 16 segments (5.0%) and 7 segments (3.4%) where MI was not detected on SPECT and FDG-PET, respectively. Conclusion MDCT is useful for determining myocardial viability in patients with myocardial infarction and more sensitive than SPECT and FDG-PET in detecting a nonviable myocardium.

Diagnostic sensitivity of multidetector-row spiral computed tomography angiography in the evaluation of type-ii endoleaks and their source: comparison between axial scans and reformatting techniques

After endovascular stent-graft placement, several complications may occur. Retrograde filling of the aneurysm (type-II endoleak) is the most common. To evaluate the accuracy, image quality, and interobserver agreement of multidetector-row spiral computed tomography angiography (MDCTA) in the diagnosis of type-II endoleak, by using various types of reformatting techniques in comparison to regular axial images. Twenty-four patients who had had endovascular repair of an infrarenal abdominal aortic aneurysm with stent graft were retrospectively studied. In 12 of 24 patients, a type-II endoleak was found. CT scans were obtained after intravenous administration of 130 ml of nonionic contrast material using a 4-6-ml/s flow rate. All patients were investigated with axial scans, multiplanar reconstruction (MPR), maximum intensity projection (MIP), shaded-surface display (SSD), and volume-rendering (VR) techniques. For each patient and for each reconstruction method, the image quality of the scans was scored as 0 for bad quality, 1 for poor quality, 2 for good quality, and 3 for excellent quality images. Two radiologists reviewed the CT images independently. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated for each reconstruction method, with the axial images as the reference method. Interobserver agreement and kappa value were also recorded. MPR showed the highest sensitivity (83% and 67% for observers 1 and 2, respectively), PPV (91% and 80% for observers 1 and 2, respectively), and NPV (85% and 71% for observers 1 and 2, respectively), whereas VR showed the highest specificity (92% for both observer 1 and 2). Reformatting techniques provide good-quality images; nevertheless, their efficacy in the study of type-II endoleak was found to be suboptimal in comparison to regular axial images. The MPR technique is probably the best choice in conjunction with axial images.

Multidetector-Row CT Angiography Diagnostic Sensitivity in Evaluation of Renal Artery Stenosis

The aim of this study was to assess the image quality and interobserver agreement of various multidetector-row computed tomographic angiography postprocessing techniques in the diagnosis of renal artery stenosis (RAS). We studied 36 patients (21 men and 15 women; mean age, 49 years) who underwent computed tomography angiography to assess renal arteries for suspected RAS. Patients were analyzed by using a multidetector-row computed tomography. Computer tomographic scans were obtained after intravenous bolus administration of 110 to 140 mL of nonionic contrast material using a 4- to 6-mL/s flow rate. We assessed every patient by using axial scans, multiplanar reconstruction (MPR), maximum intensity projection (MIP), and volume rendering (VR) techniques. For each patient and for each reconstruction method, the image quality of the main renal artery was scored as 0 for bad-quality, 1 for poor-quality, 2 for good-quality, and 3 for excellent-quality images. Two radiologists reviewed computed tomographic images independently. We calculated interobserver agreement and kappa value. We correlated the stenosis degree observed by the 2 readers with the type of reconstruction used. Overall number of renal arteries studied was 72, and we detected 24 RAS. Quality images obtained an overall (averaged between the 2 observers) value of 133 of 216, 163 of 216, and 145 of 216 for MPR, MIP, and VR, respectively. Our data underlined a statistical difference between MPR images and VR images (P < 0.001). Moreover, we noticed that the images classified as excellent were obtained from a vessel with 350 Hounsfield units or higher. Kappa value was good in MIP and VR methods evaluation but poor with the use of MPR. Reformatting techniques usually provided a high visual impact, and in our study, MIP and VR showed the best diagnostic interobserver agreement in quality and reproducibility of stenosis degree.

Optimal dose and injection duration (injection rate) of contrast material for depiction of hypervascular hepatocellular carcinomas by multidetector CT

The aim of this study was to investigate the optimal dose and injection duration of contrast material (CM) for depicting hypervascular hepatocellular carcinomas (HCCs) during the hepatic arterial phase with multidetector row computed tomography (CT). The study population consisted of 71 patients with hypervascular HCCs. After unenhanced scans, the first (early arterial phase, or EAP), second (late arterial phase, or LAP), and third (equilibrium phase) scanning was started at 30, 43, and 180 s after injection of contrast material (CM). During a 33-s period, patients with a body weight < or =50 kg received 100 ml of non-ionic CM with an iodine concentration of 300 mg I/ml; patients whose body weight was >50 kg received 100 ml of CM with an iodine concentration of 370 mg I/ml. First, we measured enhancement in the abdominal aorta and tumor-to-liver contrast (TLC) during the EAP and LAP. Next, to investigate the relation between aortic enhancement and TLC during the LAP, two radiologists visually assessed the conspicuity of hypervascular HCCs during the LAP using a 3-point scale: grade 1, poor; grade 2, fair; grade 3, excellent. Finally, to examine the effect of the CM dose and injection duration on aortic enhancement during the EAP, we simulated aortic enhancement curves using test bolus data obtained for 10 HCC patients and the method of Fleischmann and Hittmair. A relatively strong correlation was observed between aortic enhancement during the EAP and TLC during the LAP (correlation coefficient r = 0.75, P < 0.001). The 95% confidence intervals for the population mean for aortic enhancement during EAP in patients with tumor conspicuity grades of 1, 2, and 3 were 188.5, 222.4; 228.8, 259.3; and 280.2, 322.5 HU (Hounsfield Unit), respectively. Thus, we considered the lower limit of the aortic enhancement value for excellent depiction of HCCs during EAP to be 280 HU. To achieve an aortic enhancement value of >280 HU for aortic enhancement simulations during EAP, the injection duration should be <25 s for patients receiving a CM dose of 1.7 ml/kg with 300 mg I/ml iodine and <30 s for those receiving 2.0 ml/kg. For excellent depiction of hypervascular HCCs during the hepatic arterial phase, the injection duration should be <25 s in patients receiving a CM dose of 1.7 ml/kg with 300 mg I/ml iodine and <30 s for patients receiving 2.0 ml/kg.

Endovascular conversion with femorofemoral bypass as a treatment of endotension and aneurysm sac enlargement

We report a case of a patient treated with a Gore Excluder endograft for AAA in November 2003 with subsequent aneurysm sac enlargement in the absence of an identified endoleak. The patient had a Type I endoleak treated with a Palmaz stent at the neck and later developed a Type II endoleak treated with translumbar coil embolization. This was successful with absence of pressure in the sac after the procedure and stable aneurysm size over the next nine months. Surveillance of the patient with both CT and ultrasound then revealed an increase in the aortic sac diameter in the absence of endoleak. A Cook Zenith converter was used to reline this PTFE endograft. Subsequently, imaging showed aneurysm sac shrinkage. This is a report of endotension with aneurysm expansion following Gore Excluder placement which was treated successfully with a dacron endograft.

Multidetector-row computed tomography diagnosis of coronary artery aneurysms and collateral vessel after Kawasaki disease in an adult

A 54-year-old man was referred to our hospital for assessment of an oval calcified mass in the left middle mediastinum on a chest X-ray (Fig. 1). He had an episode of high-grade fever persisting for 10 days when he was 4 years old, but otherwise healthy ever since. His electrocardiogram was normal. Multidetector-row computed tomography (MDCT) was performed with the provisional diagnosis of coronary artery aneurysm. MDCT was performed using an Aquillion 16 (16-detector-row, Toshiba, Japan) with a collimation of 0.5 mm, table feed of 3.2 mm/rotation, 120 kV, 400 mA, and gantry rotation time of 0.4 s. Our scan protocol and image reconstruction method have been reported previously [1]. Metoprolol (40 mg) was given 90 min prior to the scan. Following determination of contrast transit time from the venous injection to the maximum enhancement in the ascending aorta by injecting 15 ml of nonionic contrast medium (Iomeron 350, 100 ml syringe, Eisai, Tokyo, Japan), the remaining contrast medium (85 ml) was injected at a speed of 3.5 ml/s. The heart rate immediately before the scan

Multidetector CT of Pancreas: Effects of Contrast Material Flow Rate and Individualized Scan Delay on Enhancement of Pancreas and Tumor Contrast

To prospectively assess whether high contrast material flow rate (8 mL/sec) and individualized scan delay improve enhancement of normal pancreas with multidetector computed tomography (CT) and, as a result, tumor-to-pancreas contrast of pancreatic adenocarcinoma. Informed consent was obtained in 40 patients (21 women, 19 men; mean age, 67.1 years); the institutional review board approved this protocol. Patients were referred for multidetector CT because they were suspected of having a pancreatic tumor and were randomized to receive 150 mL of nonionic contrast material (300 mg of iodine per milliliter) at a flow rate of 4 mL/sec (n = 21) or 8 mL/sec (n = 19). Patients underwent dynamic scanning at one level every 2 seconds for 66 seconds after intravenous administration of contrast material. Contrast enhancement of pancreas and tumors was measured with circular regions of interest (analysis of variance and Bonferroni-Holm corrected post hoc t tests). Peak contrast enhancement in pancreas was observed significantly earlier (mean +/- standard deviation, 28.7 seconds +/- 3.5 vs 48.2 seconds +/- 5.3; P < .05) and was significantly higher (129.0 HU +/- 25.7 vs 106.2 HU +/- 35.4, P < .05) with a flow rate of 8 mL/sec than with a flow rate of 4 mL/sec. Tumor-to-pancreas contrast greater than 40 HU lasted significantly longer with a flow rate of 8 mL/sec than with a flow rate of 4 mL/sec (26.4 seconds +/- 11.9 vs 8.6 seconds +/- 8.3, P < .05). With a flow rate of 8 mL/sec, an individualized scan delay of 19 seconds after aortic transit time revealed higher tumor-to-pancreas contrast than did a fixed scan delay, and tumor conspicuity was better. With 16-section CT, increased contrast material flow rate of 8 mL/sec and individualized scan delay were associated with improved pancreatic enhancement and tumor-to-pancreas contrast compared with flow rate of 4 mL/sec and fixed scan delay.

Inflow Stenoses in Dysfunctional Hemodialysis Access Fistulae and Grafts

The aim of the study is to prospectively determine the incidence of inflow stenoses in dysfunctional hemodialysis access arteriovenous fistulae (AVFs) and grafts (AVGs). Contrast-enhanced magnetic resonance angiography (CE-MRA) was performed of 66 dysfunctional AVFs and 35 AVGs in 56 men and 45 women (mean age, 62 years; age range, 31 to 86 years). Complete inflow (from the subclavian artery), shunt region, and complete outflow (including subclavian vein) were shown at CE-MRA. In addition to standard digital subtraction angiography (DSA) of the shunt region and outflow, DSA of the complete inflow was obtained through access catheterization of all cases in which CE-MRA showed an inflow stenosis. Vascular stenosis is defined as greater than 50% decrease in luminal diameter compared with an uninvolved vascular segment located adjacent to the stenosis. Endovascular intervention of stenoses was performed in connection with DSA. CE-MRA showed 19 arterial stenoses in 14 patients (14%). DSA confirmed 18 of these lesions in 13 patients and showed no additional inflow lesions. Of the 13 patients, 7 patients had arterial stenoses only and 6 patients had accompanying stenoses in the shunt region and/or outflow. Referral criteria for the 13 patients to undergo access evaluation had been decreased flow rates (9 patients), steal symptoms (2 patients), and insufficient access maturation (2 patients). Access flow of the 9 patients with a low-flow access improved from 477 +/- 74 mL/min to 825 +/- 199 mL/min after angioplasty. One patient with steal symptoms became symptom free after angioplasty. Endovascular intervention in 3 patients proved to be unsuccessful. Inflow stenoses are not uncommon in dysfunctional hemodialysis access shunts. We suggest that radiological evaluation comprise assessment of the complete arterial inflow.

Frequency and Outcomes of Acute Renal Failure Following Thoracic Aortic Stent-Graft Placement

We assessed the incidence, correlates, and outcomes of acute renal failure (ARF) after thoracic aortic stent-graft placement. Postprocedural ARF is an inherent complication of catheter-based interventional procedures that use intra-arterial contrast agents and has adverse effects on short- and long-term outcomes. However, few data exist on the incidence, predictors, and outcomes of ARF after thoracic aortic stent-graft placement. We analyzed data of 97 patients (64.4 +/- 11.6 years of age; 73% men) who underwent thoracic aortic stent-graft placement from July 1999 to October 2005. Postprocedural ARF was defined as an increase > or = 25% and/or > or = 0.5 mg/dl in preprocedural serum creatinine at 48 hours after the procedure. Baseline estimated glomerular filtration rate was 65 +/- 24 ml/min/1.73 m2. Chronic kidney disease (glomerular filtration rate < or = 60 ml/min/1.73 m2) at baseline was present in 45% of patients. During the stent-graft procedure, patients received 307 +/- 188 ml of nonionic contrast medium. Postprocedural ARF occurred in 33 patients (34%), and 3 required dialysis. Multivariable analysis identified American Society of Anesthesiologists class > 3 (odds ratio 5.53, 95% confidence interval 1.71 to 17.85, p = 0.004) and duration of the stent-graft procedure (odds ratio 1.01, 95% confidence interval 1.001 to 1.014, p = 0.022) as independent predictors of postprocedural ARF. Compared with patients without ARF, those with ARF had markedly higher 30-day (18.2 +/- 6.7% vs 1.6 +/- 1.6%, p = 0.0022) and 1-year (35.2 +/- 8.6% vs 10.1 +/- 3.9%, p = 0.001) mortality. In conclusion, postprocedural ARF is a frequent complication of thoracic aortic stent-graft placement and has a significant adverse effect on 30-day and 1-year survival. Baseline factors identified in our study as associated with increased risk of ARF may facilitate a comprehensive informed consent process by way of patient education. In addition, identification of an at-risk subset may allow modification of reversible periprocedural factors that may help decrease postprocedural ARF.