Enhanced detection of blood flow in the normal canine prostate using an ultrasound contrast agent

A meta-analysis evaluating contrast-enhanced intraoperative ultrasound (CE-IOUS) in the context of surgery for colorectal liver metastases

BACKGROUND

This study aimed to assess the outcomes of contrast-enhanced intraoperative ultrasound (CE-IOUS) for patients with colorectal liver metastases (CRLMs) undergoing surgery.

METHOD

A thorough literature search was performed in PubMed, Scopus, and Cochrane databases, in accordance with the PRISMA guidelines. The Odds Ratio, Weighted Mean Difference, and 95% Confidence Interval were evaluated, by means of Random-Effects model.

RESULTS

Eleven articles met the inclusion criteria and incorporated 497 patients. The present study shows that CE-IOUS is associated with higher sensitivity and accuracy compared with multidetector computed tomography (MDCT), magnetic resonance imaging (MRI), and intraoperative ultrasound (IOUS) in identifying CRLMs (p < 0.05). The positive predictive value was similar among the different modalities. Furthermore, new CRLMs were identified by CE-IOUS, thus affecting the surgical plan in 128 patients (51.8% of the patients with new CRLMs). Moreover, 91 patients (71%) underwent a more extensive hepatectomy and 15 patients (11.7%) were considered non-operable. Two alternative contrast agents, Sonazoid and Sonovue, were employed with similar sensitivity (p > 0.05).

CONCLUSION

These outcomes suggest the superiority of the CE-IOUS over MDCT, MRI, and IOUS for the staging of patients with CRLMs undergoing surgery. However, they should be treated with caution given the small number of the included studies.

Enhanced patterns on intraoperative contrast-enhanced ultrasonography predict outcomes after curative liver resection in patients with hepatocellular carcinoma

PURPOSE

This study aimed to clarify what hepatocellular carcinoma (HCC) phenotype, as categorized by intraoperative contrast-enhanced ultrasonography (CEUS), showed a high risk of recurrence after hepatic resection.

METHODS

Patients who underwent initial curative hepatectomy with intraoperative CEUS for a single HCC nodule were retrospectively assigned to three patterns of fine (FI), vascular (VA), and irregular (IR) according to the maximum intensity projection pattern based on intraoperative CEUS. Staining was performed for Ki-67, pyruvate kinase type M2 (PKM2), and vascular endothelial growth factor (VEGF) to assess the tumor proliferative activity, tumor glucose metabolism, and angiogenesis, respectively.

RESULTS

Of 116 patients, 18, 50, and 48 were assigned to the FI, VA and IR patterns, respectively. IR patients demonstrated a significantly worse prognosis for both the recurrence-free survival (RFS) and overall survival (OS) (P = 0.0002, 0.0262, respectively) than did patients with other patterns. A multivariate analysis revealed an IR pattern in intraoperative CEUS to be an independent predictive factor for a poor RFS, and major hepatectomy and an IR pattern were independent predictive factors for a poor OS. An IR pattern was closely related to the tumor size (≥ 3.3 cm) and poor histological differentiation and showed a high Ki-67 index, low VEGF expression, and high PKM2 expression.

CONCLUSION

IR-pattern HCCs as classified by intraoperative CEUS may be associated with a higher risk of recurrence and worse outcomes in HCC patients after hepatic resection than other patterns.

Contrast-Enhanced Intraoperative Ultrasound Improved Sensitivity and Positive Predictive Value in Colorectal Liver Metastasis: a Systematic Review and Meta-Analysis

BACKGROUND

The diagnostic accuracy of imaging modalities in colorectal cancer liver metastases (CRLM) has improved in recent years, therefore the role of current imaging techniques needs to be defined.

OBJECTIVE

The aim of this study was to assess the diagnostic performance of magnetic resonance imaging, preoperative imaging (magnetic resonance imaging or computed tomography), intraoperative ultrasound, and contrast-enhanced intraoperative ultrasound in the detection of CRLM.

MATERIALS AND METHODS

Eligible trials published before 30 March 2020 were identified from the EMBASE, PubMed, Web of Science, and Cochrane Library databases, and descriptive and quantitative data were extracted. Study quality was evaluated for the identified studies and a random-effects model was used to determine the integrated diagnosis estimation. Meta-regression was implemented to explore the possible contributors to heterogeneity.

RESULTS

Overall, 13 studies were included for analysis, comprising 682 patients with a total of 2303 liver lesions. The pooled sensitivity, specificity, and diagnostic odds ratio of contrast-enhanced intraoperative ultrasound were 0.94 (95% confidence interval [CI] 0.89-0.97), 0.83 (95% CI 0.67-0.92), and 79 (95% CI 32-196), respectively. The overall weighted area under the curve was 0.96 (95% CI 0.94-0.97). In univariate meta-regression analysis, disappearing liver metastasis, contrast agent, and Kupffer phase were the potent sources of heterogeneity; however, in multivariate meta-regression, no definite variable was the source of the study heterogeneity.

CONCLUSION

Contrast-enhanced intraoperative ultrasound demonstrated a high sensitivity and specificity for screening CRLM.

Ejaculation effect on blood testosterone and prostatic pulsed-wave Doppler ultrasound in dogs

Local vessels ultrasonography evaluates prostatic physio-pathologic states. Testosterone promotes tissue and vascular growth. Knowing variables on prostatic vasculature is crucial to correctly apply Pulsed-Wave exam. The study aims to assess how ejaculation and blood testosterone affect Pulsed-Wave indexes. Serial blood testosterone dosages and Pulsed-Wave exams were performed in 20 dogs, immediately before (T0) and after (T1) ejaculation and 6 hr later (T2). Arteria prostatica cranialis, Arteriola capsularis, Arteriola trabecularis and Arteriola parenchimalis were evaluated and mean Pulsatility and Resistivity Index, Systolic-Peak, End-Diastolic and Mean Velocity calculated. Data were grouped by time and vessel (ANOVA, p ≤ 0.05). At T1, Resistivity Index significantly lowered in A. prostatica cranialis, A. trabecularis and A. parenchimalis but grew in A. capsularis; Pulsatility Index had the same pattern, but not significant in A. parenchimalis; Systolic Peak Velocity, End-Diastolic Velocity, Mean Velocity significantly rose in A. capsularis and A. trabecularis. No indexes differed at T0 and T2. Testosterone did not differ at T0 (10.93 ± 7.05 ng/ml), T1 (12.71 ± 7.29) and T2 (10.54 ± 6.63). Results stated the risen prostatic vascular flow postejaculation, affecting Pulsed-Wave. Due to semi-rigid capsule, impairing vasodilation of other vessels, only A. capsularis indexes increased. Intimal cushions of A. prostatica cranialis kept velocities fixed; A. capsularis and A. trabecularis lack of intimal cushions, thus velocities grew. In A. parenchimalis, precapillary sphincters opening allows increased flow redistribution in vasodilated parenchymal bed, keeping velocities fixed. As testosterone, not affected by ejaculation, did not peak, vascular changes are not due to testosterone itself. These physiological effects of ejaculation suggest proper sexual rest before Pulsed-Wave exam planned to explore suspected prostatic neovascularization.

New malignant grading system for hepatocellular carcinoma using the Sonazoid contrast agent for ultrasonography

BACKGROUND

The ultrasonography contrast agent Sonazoid provides parenchyma-specific contrast imaging (Kupffer imaging) based on its accumulation in Kupffer cells. This agent also facilitates imaging of the fine vascular architecture in tumors through maximum intensity projection (MIP). We examined the clinical utility of the malignancy grading system for hepatocellular carcinoma (HCC) using a combination of 2 different contrast-enhanced ultrasonography images.

METHODS

We studied 121 histologically confirmed cases of HCC (well-differentiated, 45; moderately differentiated, 70; poorly differentiated, 6). The results of Kupffer imaging were classified as (1) iso-echoic pattern or (2) hypo-echoic pattern. The MIP patterns produced were classified into one of the following categories: fine, tumor vessels were not clearly visualized and only fine vessels were visualized; vascular, tumor vessels were visualized clearly; irregular, tumor vessels were thick and irregular. Based on the combined assessment of Kupffer imaging and the MIP pattern, the samples were classified into 4 grades: Grade 1 (iso-fine/vascular), Grade 2 (hypo-fine), Grade 3 (hypo-vascular), and Grade 4 (hypo-irregular).

RESULTS

The distribution of moderately and poorly differentiated HCCs was as follows: Grade 1, 4 % (1/24); Grade 2, 52 % (15/29); Grade 3, 85 % (44/52); and Grade 4, 100 % (16/16). The grading system also predicted portal vein invasion in 72 resected HCCs: Grade 1, 0 % (0/4); Grade 2, 13 % (1/8); Grade 3, 23 % (11/48); and Grade 4, 67 % (8/12).

CONCLUSIONS

This new malignant grading system is useful for estimation of histological differentiation and portal vein invasion of HCC.

Contrast-enhanced ultrasonography evaluation of radiofrequency ablation of the prostate: a canine model

BACKGROUND AND PURPOSE

Currently, there is no reliable method of monitoring the propagation of radiofrequency lesions in real time. We report our animal experience using contrast-enhanced ultrasonography (CEUS) to evaluate the lesion produced by radiofrequency ablation (RFA) in a canine model and investigate the feasibility to predict these lesions.

MATERIALS AND METHODS

Five male beagle dogs underwent RFA of the prostate. Radiofrequency was delivered under transrectal ultrasonography guidance. We created a lesion in the right and left lateral lobes of canine prostate. Post-RFA lesion size was measured with conventional ultrasonography and contrast-enhanced low-mechanical index perfusion imaging (ESAOTE DU8, CnTI) with a second-generation contrast agent (Sonovue). The prostates were assessed for a contrast void corresponding to the ablated tissue. All dogs were then immediately killed, and the prostates were harvested for pathologic analysis. The gross RFA lesions were measured to compare lesion size with that measured using CEUS.

RESULTS

The RFA lesions could not be imaged accurately in real time with conventional grayscale or power Doppler sonography. With CEUS imaging, a clear lesion was identified at the site of each RFA application. As measured by CEUS, the lesions volume averaged 1.30 +/- 0.50 cm(3), compared with 1.32 +/- 0.53 cm(3) by measurement in the gross specimen (p = 0.324).

CONCLUSIONS

CEUS appears to be an accurate modality for immediate monitoring of RFA procedure. Further study is necessary to assess the clinical utility of CEUS for monitoring RFA of localized prostate cancer.

Usefulness of Sonazoid contrast-enhanced ultrasonography for hepatocellular carcinoma: comparison with pathological diagnosis and superparamagnetic iron oxide magnetic resonance images

OBJECTIVE

We investigated the usefulness of Sonazoid contrast-enhanced ultrasonography (Sonazoid-CEUS) in the diagnosis of hepatocellular carcinoma (HCC). The examination was performed by comparing the images during the Kupffer phase of Sonazoid-CEUS with superparamagnetic iron oxide magnetic resonance (SPIO-MRI).

METHODS

The subjects were 48 HCC nodules which were histologically diagnosed (well-differentiated HCC, n=13; moderately differentiated HCC, n=30; poorly differentiated HCC, n=5). We performed Sonazoid-CEUS and SPIO-MRI on all subjects. In the Kupffer phase of Sonazoid-CEUS, the differences in the contrast agent uptake between the tumorous and non-tumorous areas were quantified as the Kupffer phase ratio and compared. In the SPIO-MRI, it was quantified as the SPIO-intensity index. We then compared these results with the histological differentiation of HCCs.

RESULTS

The Kupffer phase ratio decreased as the HCCs became less differentiated (P<0.0001; Kruskal-Wallis test). The SPIO-intensity index also decreased as HCCs became less differentiated (P<0.0001). A positive correlation was found between the Kupffer phase ratio and the SPIO-MRI index (r=0.839). In the Kupffer phase of Sonazoid-CEUS, all of the moderately and poorly differentiated HCCs appeared hypoechoic and were detected as a perfusion defect, whereas the majority (9 of 13 cases, 69.2%) of the well-differentiated HCCs had an isoechoic pattern. The Kupffer phase images of Sonazoid-CEUS and SPIO-MRI matched perfectly (100%) in all of the moderately and poorly differentiated HCCs.

CONCLUSION

Sonazoid-CEUS is useful for estimating histological grading of HCCs. It is a modality that could potentially replace SPIO-MRI.

Contrast-enhanced intraoperative ultrasonography equipped with late Kupffer-phase image obtained by sonazoid in patients with colorectal liver metastases

AIM: To find occult metastases during hepatectomy in patients with colorectal cancer liver metastases (CRCLM), contrast-enhanced intraoperative ultrasonography (CE-IOUS) was performed using a new microbubble agent, sonazoid, which provides a parenchyma-specific contrast image based on its accumulation in the Kupffer cells.

METHODS: Eight patients with CRCLM underwent CE-IOUS using sonazoid before hepatectomy. The liver was investigated during a late Kupffer-phase imaging, which is a valuable characteristic of sonazoid.

RESULTS: CE-IOUS using sonazoid provided the early vascular- and sinusoidal-phase images for

10 min followed by the late Kupffer-phase image up to 30 min after the injection of sonazoid. IOUS did not provide new findings of metastatic lesion in the 8 patients. However, during the late Kupffer-phase image of sonazoid, a metastatic lesion was newly found in two of the 8 patients. These newly detected lesions were removed by an additional hepatectomy and histopathologically diagnosed as a metastasis.

CONCLUSION: CE-IOUS using sonazoid can allow surgeons to investigate the whole liver with enough time and to find new metastases intraoperatively.

Contrast Enhanced Ultrasound for Radio Frequency Ablation of Canine Prostates: Initial Results

PURPOSE

We determined the feasibility of contrast enhanced ultrasound for radio frequency ablation of the entire prostate as a method of minimally invasive treatment for prostate cancer in a canine model.

MATERIALS AND METHODS

Approval of the Institutional Animal Use and Care committee was obtained. Initially 5 dogs (group 1) were tested using variable power (5 to 30 W), time (4 to 12 minutes), bolus (0.01 to 0.04 ml/kg) and infusion (3 to 11 ml per minute at 0.015 microl/kg) injections of an ultrasound contrast agent with conventional grayscale power Doppler and pulse inversion harmonic imaging to establish optimal parameters. Subsequently 4 dogs (group 2) underwent entire prostate ablation using parameters based on group 1. The size of the thermal lesions and residual viable tissue was measured with ImageJ software (National Institutes of Health, Bethesda, Maryland) on ultrasound and pathological study. Linear regression and Student's t test were used for statistical analysis.

RESULTS

A bolus of 0.04 ml/kg, an infusion of 11 ml per minute at 0.015 microl/kg and the contrast enhanced pulse inversion harmonic imaging mode were ranked best for guiding ablation. Thermal lesion volume was proportional to ablation power and time. There was no significant difference in measured thermal lesion size in group 1 between ultrasound and pathological findings (mean +/- SD 1.51 +/- 0.74 and 1.46 +/- 0.74 cm3, p = 0.56) or in residual viable tissue in group 2 (0.43 +/- 0.043 and 0.41 +/- 0.291 cm3, p = 0.21). The average volume of prostate ablation achieved in group 2 was 96.3%.

CONCLUSIONS

Contrast enhanced pulse inversion harmonic imaging is able to guide, monitor and control radio frequency ablation of the entire prostate.

Characterization of tumor imaging with microbubble-based ultrasound contrast agent, sonazoid, in rabbit liver

In order to investigate improvement of hepatic tumor detectability by Sonazoid with phase inversion imaging, the contrast effects on the liver of metastatic carcinoma-model rabbits were evaluated by videodensitometry and visual assessment. Correlation between the contrast enhancement of Sonazoid and histopathology was examined using the same animals. Electron microscopy was performed on hepatic tissue from another healthy rabbits to identify the distribution of Sonazoid microbubbles. As a result, all tumors were smaller than 12 mm in diameter, and after intravenous injection of Sonazoid, they were surrounded with a ring of enhanced signal during the early phase (up to 30 s), followed by a clear contrast defect during the delayed phase (after 10 min). Histopathologic observation revealed that the ring-enhancement was caused by neovasculature in the tumor, and the contrast defects corresponded to living and dead parts of tumors, which lack Kupffer cells. Videodensitometric differences between tumor and healthy tissue markedly increased at delayed phase, and visual detectability of tumors was improved when Sonazoid was used. Ultrastructural analysis showed microbubble-like structures in Kupffer cells, which indicated that Sonazoid microbubbles were taken up with these cells. In conclusion, Sonazoid, used with phase inversion imaging, greatly increases the detectability of small hepatic tumors by highlighting neovascularity at early phase and providing clear contrast defects due to absence of Kupffer cells, which take up Sonazoid microbubbles, at delayed phase.

Vaskuläre Bildgebung mittels kontrastverstärkter Sonographie in der experimentellen Anwendung

The possibility of employing contrast-enhanced ultrasound for sensitive detection of perfusion has resulted in new forms of application in fundamental medical biological research that go far beyond mere preclinical evaluation of these techniques. This contribution explains the methods for visualization and quantification of perfusion with contrast-enhanced sonography and provides an overview of how these functional examinations have been used to date. The procedure is generally considered indicated when information on tissue perfusion using ultrasound is required. This topic is also gaining increasing clinical interest, e.g., for assessment of myocardial, cerebral, and renal perfusion or for monitoring therapy. Among the various new treatment procedures that have been investigated in animal models with ultrasound, particularly pro-angiogenic and antiangiogenic therapy approaches predict promising new fields for application of contrast-enhanced ultrasound.

Extraglandular and intraglandular vascularization of canine prostate

The literature on the vascularization of the canine prostate is reviewed and the clinical significance of prostate morphology is described. Scanning Electron Microscopy (SEM), combined with improved corrosion casting methods, reveal new morphological details that promise better diagnostics and treatment but also require expansion of clinical nomenclature. A proposal is made for including two previously unnamed veins in Nomina Anatomica Veterinaria (NAV). The canine prostate has two lobes with independent vascularization. Each lobe is supplied through the left and right a. prostatica, respectively. The a. prostatica sprouts three small vessels (cranial, middle, and caudal) towards the prostate gland. A. prostatica is a small-size artery whose wall structure is similar to the arteries of the muscular type. V. prostatica is a small-size valved vein. The canine prostate has capsular, parenchymal, and urethral vascular zones. The surface vessels of the capsule are predominantly veins and the diameter of arterial vessels is larger than that of the veins. The trabecular vessels are of two types: direct and branched. The prostate parenchyma is supplied by branches of the trabecular vessels. The periacinary capillaries are fenestrated and form a net in a circular pattern. The processes of the myoepithelial cells embrace both the acins and the periacinar capillaries. In the prostate ductal system. there are spermatozoa. The prostatic part of the urethra is supplied by an independent branch of a. prostatica. The prostatic urethral part is drained by v. prostatica, the vein of the urethral bulb and the ventral prostate veins. M. urethralis begins as early as the urethral prostatic part. The greater part of the white muscle fibers in m. urethralis suggest an enhanced anaerobic metabolism.

Gray-scale liver enhancement with Sonazoid (NC100100), a novel ultrasound contrast agent; detection of hepatic tumors in a rabbit model

The liver contrast effects of Sonazoid in two ultrasonographic imaging modes, gray-scale conventional and harmonic, were examined as a time-related study in normal rabbits, and evaluated quantitatively and visually with tumor-model rabbits to estimate the diagnostic potential. Peak enhancement of vessels and parenchyma was observed 1 min after injection in both modes, although signal enhancement in the parenchyma lasted for 120 min compared with rapid decay (5-10 min) in vessels. When Sonazoid was intravenously injected into metastatic carcinoma-model (VX-2) rabbits, all hepatic tumors showed ring enhancement in the early phase followed by clear contrast defects in the delayed phase, because signal enhancement remained only in normal parenchyma. Visual analysis scores for the diagnosis of tumors were improved by Sonazoid injection, and the videodensitometric differences between tumor and normal tissues were significantly greater after injection. Although the harmonic mode tended to show better contrast effects, the conventional mode provided significant contrast enhancement in this hepatic tumor-model. Sonazoid might be useful for the detection of undifferentiated tumors in the liver by making it possible to visualize neovascularity in the early phase and clear contrast defects in the delayed phase, not only in the harmonic but also in the conventional mode.

Contrast-enhanced two- and three-dimensional sonography for evaluation of intra-abdominal hemorrhage

OBJECTIVE

To determine whether a contrast agent enhances sonographic detection of bleeding sites in the abdomen and whether contrast-enhanced three-dimensional sonography provides additional information compared with contrast-enhanced two-dimensional sonography.

METHODS

Bleeding sites were created within the livers (n = 3), spleens (n = 5), and kidneys (n = 3) of 3 dogs. A sonographic contrast agent with vascular and parenchymal enhancement capabilities was administered intravenously at a dose of 0.02 mL/kg. Before and after each contrast agent injection, the bleeding sites were imaged with two- and three-dimensional sonography in gray scale harmonic imaging and color flow modes. Sonographic findings were compared with gross pathologic findings.

RESULTS

Noncontrast-enhanced sonography was not able to show the specific location of the active bleeding in any of the organs evaluated. The contrast agent enhanced the sonographic detection of blood flow in normal vessels and extravasated blood from damaged vessels or organs in all cases. Intrasplenic and intrahepatic hematomas were better identified on delayed imaging sequences because there was marked enhancement of the normal parenchyma, whereas the hematomas remained unenhanced. Reconstructed three-dimensional sonography showed spatial relationships of the bleeding sites and surrounding structures. Gross pathologic findings were consistent with the contrast-enhanced sonographic results.

CONCLUSIONS

Contrast-enhanced sonography improves the detection and evaluation of abdominal bleeding sites. Contrast-enhanced three-dimensional sonography appears to provide additional information when compared with two-dimensional sonography.

Contrast-enhanced power Doppler imaging of normal and decreased blood flow in canine prostates

The purpose of this study was to investigate if Sonazoid, a new ultrasound (US) contrast agent, can improve the delineation of areas with normal and decreased blood flow in the prostate. Sonazoid was administered in the dose range of 0.00625-0.0375 microL microbubbles/kg into five anaesthetised mongrel adult male dogs. Transrectal power Doppler imaging of the prostate was performed in 2-D and 3-D with a C9-5 end-fire probe, using an HDI 3000 scanner. An area of decreased blood flow was created by inducing tissue ablation with a CL60 laser system, to mimic an avascular lesion. A subjective assessment of the intraprostatic vessels and the prostate vascular architecture was performed, with and without Sonazoid, before and after inducing the abnormal site. Visibility of the prostate blood flow improved following Sonazoid injection (p < 0.001). A symmetric, radial vascular pattern was identified in the normal prostate prior to tissue ablation, but only on the enhanced images. After tissue ablation, a disturbance of the normal vascular pattern and identification of areas with lack of blood flow was possible, following Sonazoid injection. Furthermore, the location and size of these areas were verified in all dogs by gross histology examination. Sonazoid enhances the visibility of the prostate vascular architecture and improves, thereby the delineation of areas with normal and decreased blood flow.

Ultrasound contrast agents: a promising future

The emerging field of contrast ultrasound has great and untapped potential. Improved vascular enhancement may increase the number and type of diagnostic vascular examinations. Improved vessel depiction may increase examination speed and improve patient throughput. New gray-scale contrast imaging techniques may substantially increase the sonographic detection and characterization of liver, kidney, and other focal parenchymal masses. Contrast ultrasound examinations may increase diagnostic confidence, decrease nondiagnostic studies, and decrease the requirement for additional imaging studies. Further investigation is needed, however, to determine the diagnostic use and cost-effectiveness of this new approach relative to CT, MR imaging, angiography, and conventional ultrasound imaging.

Enhanced visualisation of the normal prostate blood flow in young healthy volunteers using a new ultrasound contrast agent

PURPOSE

To evaluate the sonographic appearance of normal prostate vascularity before and after injection of a new ultrasound contrast agent, Sonazoid (NC100100, Nycomed Amersham).

MATERIAL AND METHODS

Five healthy male volunteers were given three injections of Sonazoid each. Transrectal B-mode, colour Doppler and colour Doppler energy (i.e. power Doppler) imaging was performed. The visibility of the vascular pattern and the vascular architecture of the prostate, including dynamics of contrast inflow and blood flow symmetry, were evaluated.

RESULTS

The depiction of the vascularity was improved in all subjects after injection of Sonazoid for both Doppler modes. No improvement was seen for B-mode. Contrast dynamics within the prostate vessels were demonstrated with a mean time from injection of the ultrasound contrast agent to enhancement of the Doppler signals in the subcapsular arteries of 14+/-1 s (11--17 s), and the ultrasound contrast agent reached the central periurethral veins 4--7 s later. A symmetric, radial, spoke-like intraprostatic vascular pattern could be identified in all subjects using power Doppler imaging and ultrasound contrast agent.

CONCLUSION

Sonazoid improved the detection of normal human prostate vascular anatomy for both colour and power Doppler imaging. Contrast dynamic studies revealed a radial spoke-like intraprostatic vascular pattern. This information might be useful in examination of patients with suspicion of prostate cancer, and needs to be further investigated.

A review of contrast media research in 1999-2000

Contrast media research published during the years 1999 and 2000 is reviewed in this article, in terms of relevance to developments within the field of diagnostic radiology. The primary focus is on publications from the journal Investigative Radiology, which publishes much of the clinical and laboratory research performed in this field. The journals Radiology and the American Journal of Roentgenology are dominant in the field of diagnostic radiology and together publish more than 10 times the number of articles as appear each year in Investigative Radiology. However, in 1999 for example, these two journals together published fewer articles than did Investigative Radiology alone that concerned basic (animal) research with contrast media. Thirty-six percent of the articles in Investigative Radiology in 1999 had a primary focus on contrast media and 18% on basic (animal) research with contrast media. To make this review more complete, articles from other major journals are cited and discussed, as needed, to provide supplemental information in the few areas not well covered by articles in Investigative Radiology. The safety of contrast media is always an important topic and research continues to be performed in this area, both to explore fundamental issues regarding iodinated contrast media and also to establish the overall safety profile of new magnetic resonance (MR) and ultrasound agents. In regard to preclinical investigations, most of the work performed in the last 2 years has been with MR and ultrasound. In MR, research efforts continue to be focused on the development of targeted agents. In ultrasound, research efforts are split between studies looking at new imaging methods and early studies of targeted agents. In regard to the clinical application of contrast media, the published literature continues to be dominated by MR. Investigations include the study of disease in clinical trials and in animal models. A large number of studies continue to be published in regard to new techniques and applications within the field of contrast-enhanced magnetic resonance angiography. This field represents the single, largest new clinical application of contrast media in MR to emerge in the last decade. New clinical research continues to be published regarding the use of contrast media in computed tomography (CT), ultrasound, and x-ray angiography. The introduction of spiral CT (together with the multidetector scanners) has led to greater utilization of this modality, as well as intravenous iodinated contrast media. The number of publications regarding clinical applications of intravenously injected ultrasound contrast agents remains low, with the high expectations in regard to growth (in terms of number of exams using contrast) of the last decade yet to be fulfilled.