Pulmonary Transit Time Assessment by CEUS in Healthy Rabbits: Feasibility, and the Effects of UCAs Dilution Concentration.

To evaluate the inter-observer variability and the intra-observer repeatability of pulmonary transit time (PTT) measurement using contrast-enhanced ultrasound (CEUS) in healthy rabbits, and assess the effects of dilution concentration of ultrasound contrast agents (UCAs) on PTT. Thirteen healthy rabbits were selected, and five concentrations UCAs of 1:200, 1:100, 1:50, 1:10, and 1:1 were injected into the right ear vein. Five digital loops were obtained from the apical 4-chamber view. Four sonographers obtained PTT by plotting the TIC of right atrium (RA) and left atrium (LA) at two time points (T1 and T2). The frame counts of the first appearance of UCAs in RA and LA had excellent inter-observer agreement, with intra-class correlations (ICC) of 0.996, 0.988, respectively. The agreement of PTT among four observers was all good at five different concentrations, with an ICC of 0.758-0.873. The reproducibility of PTT obtained by four observers at T1 and T2 was performed well, with ICC of 0.888-0.961. The median inter-observer variability across 13 rabbits was 6.5% and the median variability within 14 days for 4 observers was 1.9%, 1.7%, 2.2%, 1.9%, respectively; The PTT of 13 healthy rabbits is 1.01 ± 0.18 second. The difference of PTT between five concentrations is statistically significant. The PTT obtained by a concentration of 1:200 and 1:100 were higher than that of 1:1, while there were no significantly differences in PTT of a concentration of 1:1, 1:10, and 1:50. PTT measured by CEUS in rabbits is feasible, with excellent inter-observer and intra-observer reliability and reproducibility, and dilution concentration of UCAs influences PTT results.

Outcome of autologous platelet concentrate and gas tamponade compared to heavy silicone oil tamponade in persistent macular hole surgery.

PURPOSE: Persistence represents the major reason for failure of primary macular hole repair. A variety of surgical approaches are available for treating persistent macular holes. To compare clinical outcome of re-pars plana vitrectomy combined with autologous platelet concentrate and sulfur hexafluoride 20% gas tamponade with heavy silicone oil in persistent macular hole. METHODS: Records of 48 consecutive eyes with persistent macular holes which underwent re-pars plana vitrectomy with either heavy silicone oil (35 eyes, persistent macular-hole minimum linear diameter: 518.8 ± 171.1 µm) or autologous platelet concentrate and sulfur hexafluoride 20% (13 eyes, persistent macular hole-minimum linear diameter: 454.1 ± 211.3 µm) were reviewed retrospectively. All patients underwent measurements of anatomical persistent macular hole characteristics evaluated by optical coherence tomography and visual function. Cases in which anatomical success failed after first re-pars plana vitrectomy were treated with the other surgical techniques, comparable to a cross-over design. RESULTS: Persistent macular hole closure rate was 57.1% with autologous platelet concentrate and sulfur hexafluoride 20% and 45.7% with heavy silicone oil (p = 0.102). Functional results were comparable when persistent macular hole closure was achieved (p ⩾ 0.741), but significantly better for the autologous platelet concentrate with sulfur hexafluoride 20% group when persistent macular hole closure failed (p = 0.019). CONCLUSION: Re-pars plana vitrectomy combined with autologous platelet concentrate and sulfur hexafluoride 20% seems to achieve at least non-inferior persistent macular hole closure rates and comparable functional results when compared to heavy silicone oil, suggesting autologous platelet concentrate and sulfur hexafluoride 20% as a safe surgical alternative in persistent macular hole. Especially when persistent macular hole closure failed, autologous platelet concentrate with sulfur hexafluoride 20% seems to be superior regarding visual outcome.

Effect of Aqueous Dynamics on Gas Behavior Following Retinal Reattachment Surgery.

BACKGROUND AND OBJECTIVE: To determine how the gas concentration in air required to achieve full postoperative vitreous cavity fill varies in different aqueous outflow states. MATERIALS AND METHODS: A mathematical model was used to estimate gas dynamics. The change in gas bubble volume over time was calculated in an eye with normal aqueous outflow, ocular hypertension (OHT), and OHT with apraclonidine treatment. RESULTS: The concentration required was higher for all gases to achieve a full postoperative fill in OHT eyes versus normal eyes. Optimal gas concentrations were 22.6% for SF6, 13.9% for C2F6, and 11.6% for C3F8. Despite this, in OHT, the fill achieved was 95%, 95%, and 94% for SF6, C2F6, and C3F8, respectively. With apraclonidine, percentage fill improved for all gases. CONCLUSIONS: This is the first study to show aqueous outflow affects bubble size and indicates eyes with reduced outflow are at risk of underfill. This can ultimately affect surgical success. [Ophthalmic Surg Lasers Imaging Retina. 2020;51:522-528.].

Empirical and Theoretical Characterization of the Diffusion Process of Different Gadolinium-Based Nanoparticles within the Brain Tissue after Ultrasound-Induced Permeabilization of the Blood-Brain Barrier.

Low-intensity focused ultrasound (FUS), combined with microbubbles, is able to locally, and noninvasively, open the blood-brain barrier (BBB), allowing nanoparticles to enter the brain. We present here a study on the diffusion process of gadolinium-based MRI contrast agents within the brain extracellular space after ultrasound-induced BBB permeabilization. Three compounds were tested (MultiHance, Gadovist, and Dotarem). We characterized their diffusion through in vivo experimental tests supported by theoretical models. Specifically, by estimation of the free diffusion coefficients from in vitro studies and of apparent diffusion coefficients from in vivo experiments, we have assessed tortuosity in the right striatum of 9 Sprague Dawley rats through a model correctly describing both vascular permeability as a function of time and diffusion processes occurring in the brain tissue. This model takes into account acoustic pressure, particle size, blood pharmacokinetics, and diffusion rates. Our model is able to fully predict the result of a FUS-induced BBB opening experiment at long space and time scales. Recovered values of tortuosity are in agreement with the literature and demonstrate that our improved model allows us to assess that the chosen permeabilization protocol preserves the integrity of the brain tissue.

Ultrasound-Induced Blood-Spinal Cord Barrier Opening in Rabbits.

The blood-spinal cord barrier (BSCB) considerably limits the delivery and efficacy of treatments for spinal cord diseases. The blood-brain barrier can be safely opened with low-intensity pulsed ultrasound when microbubbles are simultaneously administered intravenously. This technique was tested on the BSCB in a rabbit model in this work. Twenty-three segments of spinal cord were sonicated with a 1-MHz unfocused pulsed ultrasound device and compared with non-sonicated segments. BSCB disruption was assessed using Evan's blue dye (EBD) extravasation. Tolerance was assessed by histologic analysis. An increased EBD concentration indicating BSCB disruption was clearly observed in sonicated segments compared with controls (p = 0.004). On one animal, which received 10 sonications, repetitive BSCB disruptions revealed no evidence of cumulative toxicity. BSCB can be disrupted using an unfocused pulsed ultrasound device in combination with microbubbles without neurotoxicity even in case of repeated sonications.

The Influencing Factors of Venous Intravasation During Transvaginal Four-dimensional Hysterosalpingo-contrast Sonography With SonoVue.

Transvaginal 4-D hysterosalpingo-contrast sonography with SonoVue (TV 4-D HyCoSy) is the preferred imaging method for evaluating tubal patency. However, venous intravasation in 4-D HyCoSy may affect the diagnosis of tubal patency. The objective of this study was to analyze influencing factors of venous intravasation during TV 4-D HyCoSy. This study included 643 infertile patients who underwent TV 4-D HyCoSy. We analyzed the relationship between the incidence of venous intravasation and patients' basic clinical data, endometrial thickness, inspection timing (clean day of menstruation) and tubal patency. A total of 169 (26.28%) patients exhibited intravasation during TV 4-D HyCoSy. The following are risk factors for venous intravation: secondary infertility, type C + C, type B + C and type B + B in bilateral fallopian tubal patency grouping; endometrial thickness ≤5.45 mm; and taking TV 4-D HyCoSy after menstruation ≤6 d. Infertility duration, intrauterine lesions, a history of pelvic inflammatory disease and a history of pelvic surgery were uncorrelated with venous intravasation. To reduce the incidence of venous intravasation, TV 4-D HyCoSy should be performed 7-10 d after menstruation or when endometrial thickness is thicker than 5.45 mm.

Intravasation Affects the Diagnostic Image Quality of Transvaginal 4-Dimensional Hysterosalpingo-Contrast Sonography With SonoVue.

OBJECTIVES: We aim to retrospectively analyze the diagnostic image quality of transvaginal 4-dimensional hysterosalpingo-contrast sonography from infertile patients and determine the significant influencing factors. METHODS: A total of 445 patients visiting infertility clinics were included in the study, of which 167 were primary infertile and 278 were secondary infertile. The factors were recorded, including age; examination time; infertility type; history of pelvic inflammatory disease, pelvic surgery, intrauterine surgery, and ectopic pregnancy; endometrial thickness; uterine position; ovarian position; 2-dimensional image quality; intravasation quantity, position, and time; balloon volume; and the dosage of contrast agent or the sterile saline solution. All the factors were compared among different diagnostic image quality groups. The method of rank logistic regression analysis was adopted to analyze the risk factors affecting the diagnostic image quality. RESULTS: Among the 445 infertile patients, 124 (27.9%) patients had intravasation occur during transvaginal 4-dimensional hysterosalpingo-contrast sonography. The diagnostic image quality between the 2 sonographers was consistent (Cronbach's alpha, 0.993). Different intravasation quantities, positions, and times; increased of balloon volume; and history of pelvic surgery were substantial risk factors for the diagnostic image quality. The diagnostic image quality diminished with the increase of intravasation. In the patient with cornual intravasation, the diagnostic image quality was substantially worse than that with non-cornual intravasation. Moreover, early onset of intravasation seriously affected the diagnostic image quality. CONCLUSIONS: In conclusion, intravasation affected the diagnostic image quality, especially early cornual massive intravasation.

Acoustic Characterization and Enhanced Ultrasound Imaging of Long-Circulating Lipid-Coated Microbubbles.

OBJECTIVES: A long-circulating lipid-coated ultrasound (US) contrast agent was fabricated to achieve a longer wash-out time and gain more resistance against higher-mechanical index sonication. Systemic physical, acoustic, and in vivo imaging experiments were performed to better understand the underlying mechanism enabling the improvement of contrast agent performance by adjusting the physical and acoustic properties of contrast agent microbubbles. METHODS: By simply altering the gas core, a kind of US contrast agent microbubble was synthesized with a similar lipid-coating shell as SonoVue microbubbles (Bracco SpA, Milan, Italy) to achieve a longer wash-out time and higher inertial cavitation threshold. To bridge the structure-performance relationship of the synthesized microbubbles, the imaging performance of the microbubbles was assessed in vivo with SonoVue as a control group. The size distribution and inertial cavitation threshold of the synthesized microbubbles were characterized, and the shell parameters of the microbubbles were determined by acoustic attenuation measurements. All of the measurements were compared with SonoVue microbubbles. RESULTS: The synthesized microbubbles had a spherical shape, a smooth, consistent membrane, and a uniform distribution, with an average diameter of 1.484 µm. According to the measured attenuation curve, the synthesized microbubbles resonated at around 2.8 MHz. Although the bubble's shell elasticity (0.2 ± 0.09 N/m) was comparable with SonoVue, it had relatively greater viscosity and inertial cavitation because of the different gas core. Imaging studies showed that the synthesized microbubbles had a longer circulation time and a better chance of fighting against rapid collapse than SonoVue. CONCLUSIONS: Nano/micrometer long-circulating lipid-coated microbubbles could be fabricated by simply altering the core composition of SonoVue microbubbles with a higher-molecular weight gas. The smaller diameter and higher inertial cavitation threshold of the synthesized microbubbles might make it easier to access deep-seated organs and give prolonged imaging enhancement in the liver.

Differentiation of Inflammatory from Fibrotic Ileal Strictures among Patients with Crohn's Disease through Analysis of Time-Intensity Curves Obtained after Microbubble Contrast Agent Injection.

The aim of the study described here was to assess whether the analysis of time-intensity curves obtained after microbubble contrast agent injection could differentiate inflammatory from fibrotic ileal strictures among patients with Crohn's disease. Sixty-five consecutive patients (40 male and 25 female; mean age ± SD, 42.2 ± 12.22 y) with stricture of the terminal ileal loop from Crohn's disease were scanned after microbubble injection. Time-intensity curves were obtained from quantitative analysis, and peak enhancement, rise time, time to peak, area under the time-intensity curve (AUC), AUC during wash-in (AUCWI) and AUC during wash-out (AUCWO) were compared between patients with inflammatory strictures and patients with fibrotic strictures. Inflammatory (n = 40) and fibrotic (n = 25) strictures differed (p < 0.05) in peak enhancement, wash-in rate, wash-in perfusion index, AUC, AUCWI and AUCWO. The quantitative analysis of small bowel wall contrast enhancement after microbubble contrast agent injection may differentiate inflammatory from fibrotic ileal strictures in patients with Crohn's disease.

Quantitative Differences Between the First and Second Injection of Contrast Agent in Contrast-Enhanced Ultrasonography of Feline Kidneys and Spleen.

Contrast-enhanced ultrasound is a valuable and safe technique for the evaluation of organ perfusion. Repeated injections of ultrasound contrast agent are often administered during the same imaging session. However, it remains unclear if quantitative differences are present between the consecutive microbubble injections. Therefore, the first and second injection of contrast agent for the left renal cortex, renal medulla and the splenic parenchyma in healthy cats were compared. A lower peak intensity and area under the curve were observed for the first injection of contrast agent in the feline kidney, both for the renal cortex and medulla, and spleen. Moreover, for the renal cortex, the time-intensity curve was steeper after the second injection. Findings from the present study demonstrate that a second injection of contrast agent provides stronger enhancement. The exact mechanism behind our findings remains unclear; however, saturation of the lung macrophages is believed to play an important role.

Straight Vessel Pattern and Rapid Filling Time: Characteristic Findings on Contrast-Enhanced Sonography of Testicular Lymphoma.

Six patients with 7 lesions that were histologically confirmed as primary testicular lymphoma were preoperatively investigated with a standardized sonographic protocol including contrast-enhanced sonography. Duplex and contrast-enhanced sonography showed marked hypervascularization in all 7 lesions. On contrast-enhanced sonography, the filling time of lymphomatous lesions was significantly shorter than the filling time of a size-matched sample of 10 patients with seminomas (P < .0001). The sonographic hallmarks of testicular lymphoma in our case series were as follows: (1) sharply demarcated homogeneous hypoechoic testicular lesions with marked hypervascularization; (2) a rapid (<7 seconds) filling time of contrast bubbles; and (3) a straight and parallel course of intralesional vessels on contrast-enhanced sonography.

Reliability, repeatability, and reproducibility of pulmonary transit time assessment by contrast enhanced echocardiography.

BACKGROUND: The aim of this study is to investigate the inter and intra-rater reliability, repeatability, and reproducibility of pulmonary transit time (PTT) measurement in patients using contrast enhanced ultrasound (CEUS), as an indirect measure of preload and left ventricular function. METHODS: Mean transit times (MTT) were measured by drawing a region of interest (ROI) in right and left cardiac ventricle in the CEUS loops. Acoustic intensity dilution curves were obtained from the ROIs. MTTs were calculated by applying model-based fitting on the dilution curves. PTT was calculated as the difference of the MTTs. Eight raters with different levels of experience measured the PTT (time moment 1) and repeated the measurement within a week (time moment 2). Reliability and agreement were assessed using intra-class correlations (ICC) and Bland-Altman analysis. Repeatability was tested by estimating the variance of means (ANOVA) of three injections in each patient at different doses. Reproducibility was tested by the ICC of the two time moments. RESULTS: Fifteen patients with heart failure were included. The mean PTT was 11.8 ± 3.1 s at time moment 1 and 11.7 ± 2.9 s at time moment 2. The inter-rater reliability for PTT was excellent (ICC = 0.94). The intra-rater reliability per rater was between 0.81-0.99. Bland-Altman analysis revealed a bias of 0.10 s within the rater groups. Reproducibility for PTT showed an ICC = 0.94 between the two time moments. ANOVA showed no significant difference between the means of the three different doses F = 0.048 (P = 0.95). The mean and standard deviation for PTT estimates at three different doses was 11.6 ± 3.3 s. CONCLUSIONS: PTT estimation using CEUS shows a high inter- and intra-rater reliability, repeatability at three different doses, and reproducibility by ROI drawing. This makes the minimally invasive PTT measurement using contrast echocardiography ready for clinical evaluation in patients with heart failure and for preload estimation.

Surface Charge Measurement of SonoVue, Definity and Optison: A Comparison of Laser Doppler Electrophoresis and Micro-Electrophoresis.

Microbubble (MB) contrast-enhanced ultrasonography is a promising tool for targeted molecular imaging. It is important to determine the MB surface charge accurately as it affects the MB interactions with cell membranes. In this article, we report the surface charge measurement of SonoVue, Definity and Optison. We compare the performance of the widely used laser Doppler electrophoresis with an in-house micro-electrophoresis system. By optically tracking MB electrophoretic velocity in a microchannel, we determined the zeta potentials of MB samples. Using micro-electrophoresis, we obtained zeta potential values for SonoVue, Definity and Optison of -28.3, -4.2 and -9.5 mV, with relative standard deviations of 5%, 48% and 8%, respectively. In comparison, laser Doppler electrophoresis gave -8.7, +0.7 and +15.8 mV with relative standard deviations of 330%, 29,000% and 130%, respectively. We found that the reliability of laser Doppler electrophoresis is compromised by MB buoyancy. Micro-electrophoresis determined zeta potential values with a 10-fold improvement in relative standard deviation.

Efficacy of contrast-enhanced ultrasound washout rate in predicting hepatocellular carcinoma differentiation.

The aim of this retrospective study was to evaluate the efficacy of contrast-enhanced ultrasound (CEUS) washout rate in predicting hepatocellular carcinoma (HCC) differentiation. Two hundred seventy-one patients underwent liver resection for HCC between April 2008 and December 2012 after being examined by CEUS using the contrast agent SonoVue with a low mechanical index (<0.1) in a routine procedure. Contrast agent washout rates obtained from video images were divided into four categories from slow to fast: WR1 = no washout in all phases (slowest); WR2 = washout after 120 s from contrast injection (late-phase washout); WR3 = washout between 41 and 120 s from contrast injection (portal venous washout); WR4 = washout before 40 s from contrast injection (fastest washout rate). HCC nodules were graded as well, moderately and poorly differentiated. Spearman rank correlation and χ(2)-tests were used to assess group relationships and differences. Receiver operating characteristic curve analysis was used to determine the diagnostic predictive value of CEUS. Among the 271 patients, 18 (6.6%) had well differentiated, 150 (55.4%) had moderately differentiated and 103 (38.0%) had poorly differentiated HCC. Statistical tests indicated that washout rate was significantly correlated with tumor differentiation (p < 0.05), and the poorly differentiated HCCs had earlier washout. At the cutoff point of WR4, CEUS based on washout rate performed poorly in distinguishing poorly differentiated from moderately and well-differentiated HCCs, with a sensitivity, specificity and accuracy (area under the curve) of 24%, 97% and 0.68, respectively. However, at the cutoff point of WR2, the sensitivity, specificity and accuracy of CEUS in differentiating well-differentiated HCC from other HCCs were significantly better: 98%, 78% and 0.96, respectively. Thus, CEUS washout rate may have a role in identifying patients with well-differentiated HCC.

Ventilation/perfusion ratios measured by multiple inert gas elimination during experimental cardiopulmonary resuscitation.

BACKGROUND: During cardiopulmonary resuscitation (CPR) the ventilation/perfusion distribution (VA /Q) within the lung is difficult to assess. This experimental study examines the capability of multiple inert gas elimination (MIGET) to determine VA /Q under CPR conditions in a pig model. METHODS: Twenty-one anaesthetised pigs were randomised to three fractions of inspired oxygen (1.0, 0.7 or 0.21). VA/ Q by micropore membrane inlet mass spectrometry-derived MIGET was determined at baseline and during CPR following induction of ventricular fibrillation. Haemodynamics, blood gases, ventilation distribution by electrical impedance tomography and return of spontaneous circulation were assessed. Intergroup differences were analysed by non-parametric testing. RESULTS: MIGET measurements were feasible in all animals with an excellent correlation of measured and predicted arterial oxygen partial pressure (R(2) = 0.96, n = 21 for baseline; R(2) = 0.82, n = 21 for CPR). CPR induces a significant shift from normal VA /Q ratios to the high VA /Q range. Electrical impedance tomography indicates a dorsal to ventral shift of the ventilation distribution. Diverging pulmonary shunt fractions induced by the three inspired oxygen levels considerably increased during CPR and were traceable by MIGET, while 100% oxygen most negatively influenced the VA /Q. Return of spontaneous circulation were achieved in 52% of the animals. CONCLUSIONS: VA /Q assessment by MIGET is feasible during CPR and provides a novel tool for experimental purposes. Changes in VA /Q caused by different oxygen fractions are traceable during CPR. Beyond pulmonary perfusion deficits, these data imply an influence of the inspired oxygen level on VA /Q. Higher oxygen levels significantly increase shunt fractions and impair the normal VA /Q ratio.

Influence of repetitive contrast agent injections on functional and molecular ultrasound measurements.

Quantitative contrast-enhanced ultrasound plays an important role in tumor characterization and treatment assessment. Besides established functional ultrasound techniques, ultrasound molecular imaging using microbubbles targeted to disease-associated markers is increasingly being applied in pre-clinical studies. Often, repeated injections of non-targeted or targeted microbubbles during the same imaging session are administered. However, the influence of repeated injections on the accuracy of the quantitative data is unclear. Therefore, in tumor-bearing mice, we investigated the influence of multiple injections of non-targeted microbubbles (SonoVue) on time to peak and peak enhancement in liver and tumor tissue and of vascular endothelial growth factor receptor 2 (VEGFR2)-targeted contrast agents (MicroMarker) on specific tumor accumulation. We found significantly decreasing values for time to peak and a tendency for increased values for peak enhancement after multiple injections. Repeated injections of VEGFR2-targeted microbubbles led to significantly increased tumor accumulation, which may result from the exposure of additional binding sites at endothelial surfaces caused by mechanical forces from destroyed microbubbles.

Doppler perfusion index and contrast-enhanced ultrasound in patients with colorectal cancer liver metastases.

BACKGROUND/AIMS: To assess the value of the Doppler perfusion index (DPI) and contrast agent for the detection of liver metastases in patients with colorectal cancer. METHODOLOGY: DPI was measured in 18 patients with colorectal cancer liver metastases and 18 control subjects. Sixteen patients were underwent contrast-enhanced ultrasonography (CEUS). RESULTS: patients with liver metastases had significantly greater DPI than control group (0.39 +/- 0.10 vs. 0.19 +/- 0.07, p < 0.05). Sixteen liver metastasis lesions underwent a rapid wash-out of contrast agent during the portal venous phase followed by a complete wash-out of SonoVue during the sinusoidal phase and were differentiated as "fast-in and fast-out" contrast enhancement patter. Another 3 lesions which were not found by baseline ultrasonography were detected to be enhancement defects at sinusoidal phases by CEUS. CONCLUSIONS: DPI is a sensitive index in detection of colorectal liver metastases; if used combined with contrast agent, much more occult liver metastasis would be detected by ultrasonography.

siRNA delivery mediated by copolymer nanoparticles, phospholipid stabilized sulphur hexafluoride microbubbles and ultrasound.

The combination of ultrasound (US) and microbubbles (MB) is a promising physical method for improving the nanoparticles (NPs) delivery efficiency. However, few concerns over comparable delivery effect of the passive or active targeting property's NPs mediated by US and MB have limited their translation towards further application. For this, we prepared small interfering RNA (siRNA)-loaded mPEG-PLGA-PLL (siRNA/mPPP) NPs with passive targeting property and siRNA-loaded mPEG-PLGA-PLL-cRGD (siRNA/mPPPR) NPs with active targeting property, and evaluated the effect of US and MB for their delivery efficiency. The experimental results demonstrated that US and MB effectively enhance the siRNA delivery efficiency of the mPPP NPs compared with the mPPP NPs alone. In contrast, an improved delivery efficiency of siRNA was not observed in PC-3 cells treated with the mPPPR NPs mediated by US and MB, suggesting that the delivery efficiency of NPs mediated US and MB also depend on its targeting properties.

Contrast dispersion imaging for cancer localization.

Cancer growth is associated with angiogenic processes in many types of cancer. Several imaging strategies have therefore been developed that target angiogenesis as a marker for cancer localization. To this end, intravascular and extravascular tissue perfusion is typically assessed by dynamic contrast enhanced (DCE) ultrasound (US) and MRI. All the proposed strategies, however, overlook important changes in the microvascular architecture that result from angiogenic processes. To overcome these limitations, we have recently introduced a new imaging strategy that analyzes the intravascular dispersion kinetics of contrast agents spreading through the microvasculature. Contrast dispersion is mainly determined by microvascular multi-path trajectories, reflecting the underlying microvascular architecture. This paper reviews the results obtained for prostate cancer localization by US and MRI dispersion imaging, also presenting the latest new developments and future perspectives.