Intravenous Contrast Administration Research Articles

Imaging characteristics of minimal fat renal angiomyolipoma with histologic correlations

ObjectivesTo review our experience with minimal fat angiomyolipomas (AMLs) and correlate the confirmed pathologic diagnosis with preoperative radiologic features to evaluate the feasibility of an accurate diagnosis preoperatively. On rare occasions, renal AMLs contain minimal amounts of fat that are not identified on cross-sectional imaging. MethodsFrom November 1998 to August 2003, 6 patients (seven lesions) underwent renal surgery with the preoperative diagnosis of renal cell carcinoma as determined by preoperative imaging studies, and the finding of AML was unexpected. A single pathologist and radiologist reviewed all pathologic specimens and radiologic examinations. The characteristic findings were recorded and compared with those in published reports. ResultsPathologic review of the specimens demonstrated microscopic amounts of mature adipocytes, abnormally thickened blood vessels, and smooth muscle cells in all seven lesions. The mean estimated fat content was 4.1% (range 3% to 10%). Hounsfield unit measurement of the lesions on unenhanced computed tomography images revealed all lesions to be hyperdense relative to the normal kidney parenchyma and enhanced by at least 90 Hounsfield units or more with the administration of intravenous contrast. Enhancement was homogenous throughout each of the seven masses. ConclusionsMinimal fat renal AML tumors are typically hyperdense relative to the normal kidney parenchyma and demonstrate homogenous enhancement with the administration of intravenous contrast on computed tomography. These results may have important implications when planning partial versus radical nephrectomy by open or minimally invasive techniques.

Optimization of indirect arthrography of the knee by application of external heat: Initial experience

To examine the potential utility of applying heat to increase the uptake of intravenous gadolinium (Gd) contrast into the knee joint in order to optimize MR arthrography. At 1.5T, 16 knees in eight patients without prior surgery, injury, or pain were examined before and 30 minutes after intravenous administration of Gd contrast (0.1 mM/kg). Between scans a heating pad was applied to the anterior aspect of eight randomly selected knees (the contralateral knee served as the control). Initial and postcontrast imaging consisted of identical axial T1-weighted sequences (TR/TE = 500/14 msec) without fat suppression. On the initial and postcontrast images, regions of interest (ROIs) were placed at identical locations in the suprapatellar pouch and the intercondylar notch by a reader blinded to the treated side. The values at these two locations were averaged and the change in joint signal intensity was calculated. The differences between the heated and unheated knees were also calculated. Seven of the eight knees treated with heat had increased joint enhancement compared to the contralateral control, with percentage changes in joint signal intensity (heated knee vs. control) of +38%, +80%, +121%, +145%, +150%, +164%, and +177%. Overall there was a doubling of signal intensity (125%) on the heated side compared to the contralateral control (with significance at P = 0.039). One patient was excluded because of a prior knee injury. The application of external heat increases uptake of intravenously administered Gd contrast into the knee joint, and may help to optimize indirect MR arthrography at a relatively low cost.

Virtual Colonoscopy by MRI: State-of-the-Art and Future Directions

MR colonography has been shown to be an appropriate diagnostic tool for the detection of colorectal lesions. The technique is based on the acquisition of T1-weighted sequences after the administration of water enema and the intravenous administration of paramagnetic contrast. This article describes the technical requirements for MR colonoscopy and the procedures of data acquisition and image interpretation. The advantages and drawbacks of MR colonoscopy also are outlined.

Venous Air Embolism from Intravenous CT Contrast Administration

3 23-year-old male pedestrian presented to the emerency department after being struck by a car. Abdominal T scan with contrast revealed no intraabdominal injuies, but air fluid level was seen in the inferior vena cava A) with air extending into the left renal vein (B). Beause these findings were not present in the correspondng precontrast images of the scan (C, D), a diagnosis of atrogenic air embolism was made and the patient was dmitted to the ICU for close observation. Contrast enhanced CT scan has emerged as the leading iagnostic modality to identify intraabdominal injuries. Indvertent injection of air is a recognized complication of ntravenous CT contrast administration, occurring in up to 1% of patients. Accidental injection of as little as 100 cc f air has been reported to be fatal. Major morbidity is aused by entrapment of air in the right ventricular outflow ract, precipitating circulatory failure. Mild-to-moderate air embolism usually does not require ny intervention other than close observation. In severe

A Slowly Growing Extraparenchymal Mass: Imaging Considerations

Abstract: Solitary fibrous tumor of the pleura (SFTP) is a rare primary pleural neoplasm that most commonly arises from visceral pleural surfaces. SFTPs consist of spindle cells embedded within variable amounts of connective tissue, and may stain positive for vimentin and antibodies to CD 34. Grossly, SFTPs often are attached to pleural surfaces via a pedicle. Most SFTPs are benign, although malignant degeneration may occur in approximately 40% of lesions. Histopathologically, malignancy is favored when high mitotic counts (greater than 4–10 per high power fields), pleomorphism, high cellularity with crowding and overlapping nuclei, tumor giant cells, necrosis, and hemorrhage are encountered. Chest radiography may show a peripheral mass that may show characteristics suggestive of an extraparenchymal location: obtuse angles with the chest wall associated with a circumscribed border on one side of the lesion and a fading margin on the other side. Cross sectional imaging findings of SFTP include a variable sized mass in contact with the chest wall or diaphragm that shows enhancement following intravenous contrast administration. Calcification and effusion are uncommon. Magnetic resonance imaging may show decreased T1 and T2 signal, consistent with the fibrous nature of the lesion. The treatment of choice for SFTP is wide surgical resection.

Differentiating Colonic Diverticulitis from Colon Cancer: The Value of Computed Tomography in the Emergency Setting

The purpose of this study was to establish practical diagnostic criteria to differentiate colonic diverticulitis from colon cancer by computed tomography (CT) in the emergency department (ER). Helical CT scans of 40 patients admitted to the ER with the clinical diagnosis of diverticulitis and 14 patients diagnosed with colon cancer were retrospectively reviewed. In total, 18 imaging parameters were analyzed and were compared between the 2 groups of patients. Thirteen parameters were found to be statistically significant for the diagnosis of colonic diverticulitis in excluding colon cancer: pericolic infiltration (p < 0.001); presence of lymph nodes (p < 0.001); inflamed diverticula (p = 0.001); non-inflamed diverticula (p = 0.001); degree of enhancement (p = 0.001); intestinal obstruction (p = 0.001); involved wall thickness (p = 0.005); lymph node size (p = 0.007); fascial thickening (p = 0.009); pattern of enhancement (p = 0.012); involved length (p = 0.014); free air (p = 0.035); and abscess formation (p = 0.042). Among these parameters, the most valuable imaging findings for diverticulitis were the presence of non-inflamed diverticulum, inflamed diverticulum, mild degree of enhancement, and small lymph node size. Three were found to have high specificity but low sensitivity: target enhancement pattern; abscess formation; and free air. When colonic obstruction is present, colon cancer is more likely than diverticulitis. Specific CT criteria help to differentiate colonic diverticulitis from colon cancer. CT scan with intravenous contrast administration would be the best noninvasive imaging modality in the ER for the accurate diagnosis and appropriate management of such disease.

A thoracoscopically resected case of mediastinal parathyroid cyst.

A 67-year-old male visited his physician because of a 2-month history of cough and sputum. An abnormal shadow at the left upper mediastinum on chest x-ray film was detected, and the patient was referred to our department for further examination. Chest x-ray film revealed a round shadow at the left upper posterior mediastinum. Computed tomography(CT)revealed a uniform iso density mass about 4 cm in diameter, with a well-defined border. After the intravenous contrast administration, a slight peripheral enhancement was seen around the mass. On magnetic resonance imaging, the mass was hypointense in T1-weighting and hyperintense in T2-weighting. The contrast pattern was the same as that observed in the CT scan. On sagittal and coronal sections, the mass was adjacent to the aortic arch. Although a benign tumor was mostly suspected based on imaging findings, a malignant tumor was also possible. Accordingly, we resected this mass with video-assisted thoracoscopy. Findings at operation were a cystic mass. The pathological findings were compatible with benign parathyroid cyst, which was suspected to be the cystic degeneration of a parathyroid adenoma.

The experimental study on bowel ischemia in closed loop obstruction by using multi-phase spiral CT

目的 探讨螺旋CT增强多期扫描对实验性闭袢性肠梗阻肠壁缺血的诊断价值.方法新西兰大白兔24只,分为3组,每组8只;取10～15 cm长小肠结扎两端成闭袢,同时结扎闭袢肠段的引流静脉;于模型制成后0.5 h(A组)、1～2 h(B组)和3～5 h(C组)行螺旋CT多期扫描.采用盲法对比分析CT表现与肠壁组织病理改变的关系.结果 A组 7只及B组 4只兔闭袢肠壁增强扫描出现持续强化,C组8只的闭袢肠壁均无明显持续强化.CT值测量:在增强前、增强后的动脉期、静脉期和延迟期A组闭胖肠壁的CT值分别为 (56.3±4.3)HU,(139.5±17.9)HU,(145.1±12.6)HU和 (124.9±10.5)HU;B组分别为 (58.8±5.6)HU,(82.5±13.7)HU,(101.0±20.3)HU和 (95.0±16.4)HU;C组分别为 (62.1±7.8)HU,(63.9±6.6)HU,(59.5±4.40)HU和 (59.6±6.9) HU.在平扫时,A组、B组、C组闭袢肠壁之间的CT值差异无统计学意义(P>0.05).在增强后的同一时期内,无论是在动脉期、静脉期或是延迟期,A组闭袢肠壁的CT值最大,B组次之,C组最小,而且差意有统计学意义(P 0.05).与病理组织学对照,肠壁无坏死组出现持续强化征象的发生率(11/13)明显高于肠壁坏死组 (1/11)(P<0.05).结论螺旋CT多期增强扫描可评价肠壁不同时间的缺血,持续强化主要见于肠壁缺血的早期阶段,而已坏死的肠壁在增强各期均无强化。

Frontiers in Cardiovascular Magnetic Resonance

Cardiovascular magnetic resonance (MR) is emerging as a multipurpose imaging modality for the assessment of cardiovascular disease in general and ischemic heart disease in particular. Currently, the pace of innovation is rapid, and the modality is changing from one that is used primarily as a research tool to one that is increasingly used in routine clinical practice. The process of innovation includes not only improvements in scanner hardware, such as coil and gradient technology, and the development of new contrast agents but also the development of novel pulse sequences. The concept of the pulse sequence, in which programming changes at the scanner can lead to fundamental changes in activating tissue, is unique to MR and gives this modality the potential to assess a vast number of biological parameters. Cardiovascular MR promises to play an important clinical and investigational role in both vascular and cardiac systems. Current and potential future applications of cardiovascular MR will be discussed with a particular focus on ischemic heart disease. Multidetector-row computed tomography, another promising and complementary noninvasive imaging technology, will be discussed briefly in relation to cardiovascular MR for the assessment of atherothrombotic disease. ### Nomenclature and Evolving Imaging Assessment Atherothrombosis is a systemic or multiterritory arterial disease that primarily affects the large- and medium systemic arteries, including the aorta and the carotid, coronary, and peripheral arteries. Although the epicardial coronary arteries appear to be the most susceptible to atherothrombosis,1,2 intramyocardial arteries are relatively resistant. The concept of multiterritory atherothrombosis has been addressed in 2 large studies of symptomatic patients that showed that at entry into the studies, 3% to 8% had symptomatic atherothrombotic disease in all 3 main arterial districts and 23% to 32% had disease in 2 districts.3,4 From a structural point of view, the 4 main components of the atherothrombotic plaques are as follows: (1) fibrocellular, …

Resonancia magnética cardíaca: aplicaciones clínicas

Cardiovascular disease is the most frequent cause of mortality in the developed countries and represents a serious social, economic and health problem. Although very diverse, useful techniques exist for diagnosing cardiac diseases, it is frequently necessary to ask for more than one test to reach a specific diagnosis. Magnetic resonance is a harmless, well tolerated and safe technique, which is currently available in the majority of hospitals. This technique makes it possible in a single exploration to study the anatomy of the heart and to make a qualitative, semi-quantitative and quantitative assessment of the parameters of cardiac function. It provides information of cardiac and vascular anatomy and function in complex congenital cardiopathies. Besides, with the administration of intravenous contrast, it enables knowledge to be gained of myocardial viability in ischaemic cardiopathy. Hence, cardiac magnetic resonance is emerging as one of the most promising techniques for the study of congenital and acquired cardiac pathology.

Efficacy of transvaginal contrast-enhanced MRI in the early staging of cervical carcinoma

The objective of this study was to evaluate the efficacy of transvaginal contrast for local staging of cervical carcinoma. Fifty patients diagnosed with cervical carcinoma prospectively underwent magnetic resonance (MR) imaging before and after vaginal opacification (VO) with a mixture of 25 ml saline and 25 ml barium. T2-weighted (T2W) TSE images in axial and sagittal planes were compared before and after vaginal opacification. Dynamic T1W images in sagittal and fat-suppressed T1W images in transverse planes were also evaluated after intravenous contrast administration. Involvement of vaginal wall, lumen, and fornices; parametrium; rectum; and bladder were noted. Changes in local tumor staging and in treatment planning were also assessed after vaginal opacification. MR results were later compared with surgical pathological findings. Twenty-eight patients who went through surgical staging were included in the study. VO did not change any of the MR interpretations in 14 patients (50%). Correct staging was achieved with T2W TSE images with and without VO (in sagittal and transverse planes) in 78.5% and 50% of the patients, respectively. VO correctly lowered staging in seven and increased it in three patients compared with sagittal standard T2W images. Treatment planning was also changed in four (14%) of these patients. When overall accuracy of MR staging to indicate the appropriate treatment was evaluated, patients would have received the proper treatment in 90% and 79% of the cases when only T2W sagittal images with and without VO were evaluated, respectively. Dynamic gradient-echo images in sagittal planes and postcontrast T1W images in transverse planes evaluated with T2W series after VO, accomplished correct staging in 23 (82%) of the patients. MRI staging in early cervical cancer may be difficult and overestimated, especially if the tumor is slightly extended into the proximal vagina. Use of vaginal contrast medium is an easy, well-tolerated, and effective method to better delineate the borders of the tumor. It increases the specificity and accuracy of MR staging by showing the exact relation of the tumor with the vaginal wall and beyond.

False Aneurysm of the Ascending Aorta Caused by a Sternal Wire

HomeCirculationVol. 111, No. 2False Aneurysm of the Ascending Aorta Caused by a Sternal Wire Free AccessReview ArticlePDF/EPUBAboutView PDFView EPUBSections ToolsAdd to favoritesDownload citationsTrack citationsPermissions ShareShare onFacebookTwitterLinked InMendeleyReddit Jump toFree AccessReview ArticlePDF/EPUBFalse Aneurysm of the Ascending Aorta Caused by a Sternal Wire Markus F. Müller, MD and Judit Ferencz, MD Markus F. MüllerMarkus F. Müller From the Department of Radiology, Sahlgrenska University Hospital, Gothenburg, Sweden. Search for more papers by this author and Judit FerenczJudit Ferencz From the Department of Radiology, Sahlgrenska University Hospital, Gothenburg, Sweden. Search for more papers by this author Originally published18 Jan 2005https://doi.org/10.1161/01.CIR.0000153382.09835.C9Circulation. 2005;111:e14A 75-year-old man was admitted to our hospital with chest pain and B symptoms. Three years earlier, he had undergone radio- and chemotherapy because of a malignant lymphoma of the left femur. During this time, the patient was clinically in remission. On admission, echocardiography revealed pericardial effusion and a 4-cm tumor in the right atrial appendage. Staging was completed with computed tomography of the thorax and abdomen, which confirmed the findings from the ultrasound examination. Open biopsy via median sternotomy was performed to make a diagnosis; the histological diagnosis was recidivation of the lymphoma. Postoperatively, the patient complained repeatedly of pain in the sternal region. Chest x-ray (Figure 1) showed that the fourth sternal wire protruded into the anterior mediastinum. ECG-gated computed tomography of the chest after intravenous contrast administration (Figure 2) depicted a false aneurysm between the 2 wires of the sternum cerclage originating from the anterior circumference of the ascending aorta. Download figureDownload PowerPointFigure 1. Posteroanterior (A) and lateral (B) chest x-ray after open biopsy of the mediastinal tumor. Note the protrusion of the fourth sternal wire (arrow, B) into the anterior mediastinum.Download figureDownload PowerPointFigure 2. Axial (A) and sagittally reformatted (B) ECG-gated computed tomography after intravenous contrast administration. The false aneurysm (arrow) of the ascending aorta is depicted between the wires of the sternum cerclage.FootnotesCorrespondence to Markus F. Müller, MD, Department of Radiology, Sahlgrenska University Hospital, Sahlgrenska, 413 45 Gothenburg, Sweden. E-mail [email protected] Previous Back to top Next FiguresReferencesRelatedDetailsCited By Ethier T, Bisleri G, Ribeiro I and Payne D (2020) Surgical Removal of Migrated Broken Sternal Wire Using Endoscopic Assistance, The Annals of Thoracic Surgery, 10.1016/j.athoracsur.2019.05.030, 109:2, (e107-e108), Online publication date: 1-Feb-2020. Marshall K and Weese S (2018) Man With Chest Pain and Lump in Neck, Annals of Emergency Medicine, 10.1016/j.annemergmed.2017.08.060, 71:2, (169-188), Online publication date: 1-Feb-2018. Herman K, Schoepf U, Bradley S and Hlavacek A (2010) Sternal erosion detected by computed tomographic angiography before repeat sternotomy in an adolescent with congenital heart disease, Journal of Cardiovascular Computed Tomography, 10.1016/j.jcct.2009.11.005, 4:1, (66-69), Online publication date: 1-Jan-2010. Dawson D, Clarke N and Banning A (2008) Management of the ascending aortic pseudo-aneurysms— A single centre experience, International Journal of Cardiology, 10.1016/j.ijcard.2007.06.071, 130:1, (92-95), Online publication date: 1-Oct-2008. Bachet J, Pirotte M, Laborde F and Guilmet D (2007) Reoperation for Giant False Aneurysm of the Thoracic Aorta: How to Reenter the Chest?, The Annals of Thoracic Surgery, 10.1016/j.athoracsur.2006.12.044, 83:5, (1610-1614), Online publication date: 1-May-2007. January 18, 2005Vol 111, Issue 2 Advertisement Article InformationMetrics https://doi.org/10.1161/01.CIR.0000153382.09835.C9PMID: 15657379 Originally publishedJanuary 18, 2005 PDF download Advertisement SubjectsComputerized Tomography (CT)

Avaliação hepática e esplênica por ressonância magnética em pacientes portadores de esquistossomose mansônica crônica

OBJETIVO: Avaliar, qualitativa e quantitativamente, as alterações morfológicas hepáticas e esplênicas por ressonância magnética (RM) em pacientes portadores de esquistossomose mansônica crônica, e a reprodutibilidade do método na avaliação hepatoesplênica destes pacientes. MATERIAIS E MÉTODOS: Realizou-se estudo prospectivo em 28 pacientes esquistossomóticos submetidos à RM de abdome superior. Os exames foram realizados em equipamento com alto campo (1,5 T), utilizando-se bobina de corpo e bomba injetora para a administração do contraste endovenoso, e interpretados por dois examinadores independentes, que avaliaram a presença de alterações morfológicas hepáticas e esplênicas. A concordância interobservador e intra-observador foram medidas pelo teste kappa e pelo teste do coeficiente de correlação intraclasses. RESULTADOS: As variáveis qualitativas e quantitativas apresentaram boa concordância interobservador e intra-observador (kapa &gt; 0,65 e r &gt; 0,66, respectivamente). A maior concordância interobservador foi obtida para o diâmetro ântero-posterior do baço (r = 0,98). Os observadores identificaram redução do lobo hepático direito, aumento do lobo hepático esquerdo e caudado associado a esplenomegalia em quase todos os pacientes, e alargamento de fissuras, heterogeneidade do parênquima hepático, irregularidade de contornos, vasos periféricos hepáticos e fibrose periportal em mais de 82% dos pacientes. CONCLUSÃO: As alterações morfológicas hepáticas caracterizam-se pela redução do lobo direito e aumento dos lobos caudado e esquerdo, e as esplênicas, pela presença de esplenomegalia e nódulos sideróticos. A RM apresenta elevada reprodutibilidade na avaliação dessas alterações em pacientes com esquistossomose mansônica crônica.

Contrast-enhanced MRI of the menisci of the knee using ultrashort echo time (UTE) pulse sequences: imaging of the red and white zones.

The objective of this study was to demonstrate the red and white zones of the meniscus of the knee using MRI. Ultrashort echo time (UTE) pulse sequences with an initial TE of 0.08 ms and later echoes at 5.95 ms, 11.08 ms and 17.70 ms were used to image the meniscus of the knee in two normal subjects before and after intravenous administration of gadodiamide. Difference images were formed by subtraction of later echo images from the first. The difference images showed obvious enhancement in an area consistent in location and dimensions with the red zone of the meniscus. Regions of interest placed within this area, central to it (corresponding to the white zone), and peripheral to it (corresponding to perimeniscal tissue) all showed increases in signal intensity after intravenous contrast administration. The greatest change in signal intensity in these regions of interest was seen with the shortest TE and in perimeniscal tissue on the original images. The increase in signal intensity was greatest in the red zone on the difference images. Using UTE pulse sequences and difference images derived from them, it is possible to visualize enhancement selectively in the red zone of the meniscus. Less obvious but significant changes in signal intensity were also present in the white zone.

Systematic review of the impact of N-acetylcysteine on contrast nephropathy

The efficacy of N-acetylcysteine (NAC) for preventing contrast nephropathy is uncertain. We performed a systematic review and meta-analysis to assess the efficacy of NAC for preventing contrast nephropathy after administration of intravenous contrast media. Data were obtained from searching MEDLINE (1969-2003) and EMBASE (1988-2003), Cochrane Controlled Clinical Trial Registry (2002, Volume 3), and conference proceedings. We considered all randomized studies that compared changes in renal function between groups that received and did not receive NAC. Studies in which the control group also received active therapy were excluded, although co-intervention directed at both groups was permitted. Two reviewers independently extracted quantitative and qualitative data. Disagreements were resolved by consensus with the aid of a third party. Fifteen studies with a total of 1776 patients satisfied inclusion and exclusion criteria. Contrast nephropathy was typically defined by an increase in serum creatinine of 0.5 mg/dL within 24 to 48 hours of contrast administration. The pooled random effect relative risk was 0.65 (0.43-1.00, P= 0.049), indicating that NAC significantly reduced the incidence of contrast nephropathy. However, the effect of NAC was not statistically significant in several prespecified subgroup analyses, and the results were not robust to the addition of hypothetical new or unidentified randomized trials. There was evidence of significant heterogeneity in NAC effect across studies (Q = 26.3, P= 0.02). Random effects meta-regression did not implicate identified differences in participant or study characteristics as responsible for the observed heterogeneity. NAC may reduce the incidence of acutely increased serum creatinine after administration of intravenous contrast, but this finding was of borderline statistical significance, and there was significant heterogeneity between trials. Before NAC becomes the standard of care for all patients receiving intravenous contrast, new randomized trials evaluating its effect on clinically relevant outcomes are required.

Differential diagnosis of cardiac masses using contrast echocardiographic perfusion imaging

ObjectivesWe investigated the usefulness of echocardiographic contrast perfusion imaging in differentiating cardiac masses. BackgroundTwo-dimensional echocardiography is the primary diagnostic modality for cardiac masses. However, differentiation between the different types of cardiac masses may be difficult at times. We hypothesized that echocardiographic contrast perfusion imaging would differentiate the neo-vascularization of malignancies from the avascularity of thrombi and the sparse vascularity of stromal tumors. MethodsSixteen patients with cardiac masses underwent power-modulation imaging after echocardiographic intravenous contrast administration. Pixel intensities in the mass and an adjacent section of myocardium were analyzed visually and by dedicated software. All masses had a pathologic diagnosis or resolved after anticoagulation. In a subset of patients, video-intensity curves of contrast replenishment in the mass and myocardium over time were generated. The post-impulse steady-state pixel intensity (A) and initial rate of contrast replenishment after impulse (β) were compared with an index of blood vessel area on pathology. ResultsIn seven of 16 patients, contrast enhancement resulted in greater pixel intensity in the mass than in the adjacent myocardium. All of these masses were classified pathologically as malignant (n = 6) or benign and vascular (n = 1). Nine masses demonstrated decreased pixel intensity, compared with the myocardium, and were diagnosed pathologically as myxomas (n = 2) or thrombi (n = 5), or they resolved with anticoagulation (n = 2). For the subset of patients, β correlated with the vessel area index (r = 0.60). ConclusionsEchocardiographic contrast perfusion imaging aids in the differentiation of cardiac masses. Compared with the adjacent myocardium, malignant and vascular tumors hyper-enhanced, whereas stromal tumors and thrombi hypo-enhanced.

Dark-lumen MR colonography.

Magnetic resonance colonography (MRC) has been shown to be an appropriate diagnostic tool for the detection of colorectal pathologies. Recently, dark-lumen MRC has been introduced. This technique is based on the acquisition of a T1-weighted sequence after the administration of water enema and the intravenous administration of paramagnetic contrast. This report describes the underlying techniques of dark-lumen MRC concerning data acquisition and image interpretation. Furthermore, it points out the advantages of this approach as compared with conventional endoscopy or other MR methods. Possible improvements in the future such as the implementation of fecal tagging strategies to avoid bowel cleansing are discussed.

Acute contrast reaction management by radiologists: a local audit study.

Consultant radiologists and trainees must possess knowledge of optimal acute management of anaphylactic/anaphylactoid contrast reactions because patient survival depends upon prompt initial management. The aim of the present study is to assess the knowledge of first-line management of these reactions among radiologists. Within one working day, and without prior knowledge, radiology consultants and trainees within four teaching hospitals in a major Australian capital city were asked to complete a confidential questionnaire regarding acute resuscitation management. Scenarios were presented of an adult who developed life-threatening symptoms of anaphylaxis immediately after intravenous contrast administration, ventricular fibrillation and profound bradycardia. Questions were asked with regards to adrenaline, corticosteroid, antihistamines, intravenous volume expansion, cardio-pulmonary rescuscitation and knowledge of the emergency telephone number. Sites were assessed for presence of an anaphylaxis management chart and also when each participant last completed a resuscitation course. Forty-two participants were recruited. Overall, 53% of questions were answered correctly. Only 43% knew the adrenaline dose and if an incorrect dose was administered it was more likely to be an overdose. Notable inadequacies were also discovered with corticosteroid, atropine, antihistamine doses and intravenous fluid use. Only 26% had completed a resuscitation course in the past 2 years. Forty-five percent knew the emergency telephone number and 55% of rooms using intravenous contrast contained an immediately visible chart for contrast reaction management. Radiologist and trainee knowledge of immediate life-threatening contrast reaction management is deficient. Severe contrast reactions are uncommon with today's use of non-ionic contrast, but they still occur. Experience in the management of anaphylaxis can only come from regular, compulsory training.

A simple position to provide better imaging of upper ureteral stones close to the crista iliaca during extracorporeal shock wave lithotripsy using the Siemens Lithostar.

The fluoroscopic image from the second plan (oblique) tube of an upper ureteral stone close to the crista iliaca may be superimposed on the pelvic bones during SWL using the Siemens Lithostar with the patient in the prone position. This creates difficulty in imaging and targeting of the stone and can necessitate using ureteral catheters before treatment and/or intravenous contrast injection during SWL. We describe a very simple, yet effective method for easier visualization of the stone under this circumstance. Between March 1992 and February 2003, we treated 1561 patients with ureteral stones by SWL with the Siemens Lithostar. The stones were localized in the upper ureter in 841. The image of the stone from the second plan (oblique) tube was superimposed on the pelvic bones in 221 in whom visualization of the stone was hardly possible with the standard prone position. By simply rotating the patient 180 degrees on the table, the superimposition of the image of the stone on the pelvic bone was obviated. This resulted in easier and better imaging of the stone during SWL. It also allowed for a clear and superior image to the treating physician during SWL. The energy and shock waves, utilization of anesthesia, number of treatment sessions, auxiliary measures, and complications were noted. Stone load was recorded in square centimeters (cm(2)). Patients were evaluated by intravenous urogram or KUB and ultrasonography when stone-free or CIRF (nonobstructive and noninfectious insignificant fragments < or =4mm) status was noted at the fluoroscopic control 2 to 4 weeks after the last session. Final CIRF decision was made 10-12 weeks after the last session. SWL was regarded as failure if no fragmentation was noted after the 3rd session. Therapy was continued if fragmentation was noted. The median age was 40 (range 5-85). The mean stone burden was 0.8 (range 0.24-2.9) cm(2). No indwelling ureteral stents were placed in any patients before and during treatment. The mean number of shock waves and energy used for the entire patient population was 2007 and 17.5kV, respectively. The median and average treatment session was 1 and 1.7, respectively. A total of 196 patients (89%) were rendered stone-free. Clinically insignificant residual fragments were present in 18 (8%). SWL was unsuccessful in 7 (3%) patients. These stones were removed by ureterorenoscopy. Intravenous contrast administration was not used to facilitate stone targeting during SWL. Anesthesia, in the form of analgesic sedation, was used in 7 (3%) patients. We did not observe any complications and adverse effects. The technique described hereby does not have an affect on coupling; it only provides a superior image of the stone to the treating physician. We advocate its application in all patients with upper ureteral stones close to the crista iliaca when the fluoroscopic image of the stone from the second plan (oblique) tube is superimposed on pelvic bones during SWL in prone position.

The most useful findings for diagnosing acute appendicitis on contrast-enhanced helical CT.

To evaluate the most useful findings to look for in diagnosing acute appendicitis on contrast-enhanced helical CT. Appendiceal helical CT scans with intravenous contrast administration (abdomen, 7-mm collimation; abdominopelvic junction, 5-mm collimation) of 71 patients with surgically proven acute appendicitis and 167 patients with alternative diagnoses were reviewed retrospectively. Three radiologists analyzed the following parameters: enlarged appendix (>6 mm in diameter), appendiceal wall thickening, appendiceal wall enhancement, no identification of the appendix, appendicolith(s), appendiceal intraluminal air, intramural air, extraluminal air, periappendiceal fat stranding, extraluminal fluid, phlegmon, abscess, lymphadenopathy, segmental terminal ileal wall thickening, focal cecal apical thickening, focal colonic wall thickening, and segmental colonic wall thickening. The features that best distinguished appendicitis from alternative diagnoses were selected with stepwise logistic regression analysis. Nine CT findings distinguished acute appendicitis from alternative diagnoses (P < 0.05): enlarged appendix (R = 0.739), appendiceal wall thickening (R = 0.525), periappendiceal fat stranding (R = 0.414), appendiceal wall enhancement (R = 0.404), focal cecal apical thickening (R = 0.171), appendicolith(s) (R = 0.157), extraluminal air (R = 0.050), intramural air (R = 0.043), and phlegmon (R = 0.030). Enlarged appendix (sensitivity, 93%; specificity, 92%), appendiceal wall thickening (sensitivity, 66%; specificity, 96%), periappendiceal fat stranding (sensitivity, 87%; specificity, 74%), and appendiceal wall enhancement (sensitivity, 75%; specificity, 85%) showed the statistically most significant association with acute appendicitis. On 5-mm-section contrast-enhanced helical CT examinations, enlarged appendix, appendiceal wall thickening, periappendiceal fat stranding, and appendiceal wall enhancement were the most useful findings for diagnosing acute appendicitis.