Megha Nayyar

Role of contrast-enhanced ultrasound (CEUS) in evaluation of thermal ablation zone.

PurposeThermal ablation has emerged as a mainstay therapy for primary and metastatic liver malignancy. Percutaneous thermal ablation is usually performed under CT and/or ultrasound guidance. CT guidance frequently utilizes iodinated contrast for tumor targeting, with additional radiation and contrast required at the end of the procedure to ensure satisfactory ablation margins. Contrast-enhanced ultrasound (CEUS) is an imaging technique utilizing microbubble contrast agents to demonstrate blood flow and tissue perfusion. In this study, we performed a retrospective review to assess the utility of CEUS in the immediate post ablation detection of residual tumor.MethodsSixty-four ablations were retrospectively reviewed. 6/64 ablations (9.4%) had residual tumor on the first follow-up imaging after thermal ablation. There were two groups of patients. Group 1 underwent standard protocol thermal ablation with CT and/or ultrasound guidance. Group 2 not only had thermal ablation with a protocol identical to group 1, but also had CEUS assessment at the conclusion of the procedure to ensure satisfactory ablation zone.ResultsThe residual tumor rate in group 1 was 16.7% and the residual tumor rate in group 2 was 0%. The difference between the groups was statistically significant with a p value of 0.023. The results suggest that using CEUS assessment immediately after the ablation procedure reduces the rate of residual tumor after thermal ablation.ConclusionCEUS evaluation at the end of an ablation procedure is a powerful technique providing critical information to the treating interventional radiologist, without additional nephrotoxic contrast or ionizing radiation.

CT prediction of the Fuhrman grade of clear cell renal cell carcinoma (RCC): towards the development of computer-assisted diagnostic method

PurposeThere are distinct quantifiable features characterizing renal cell carcinomas on contrast-enhanced CT examinations, such as peak tumor enhancement, tumor heterogeneity, and percent contrast washout. While qualitative visual impressions often suffice for diagnosis, quantitative metrics if developed and validated can add to the information available from standard of care diagnostic imaging. The purpose of this study is to assess the use of quantitative enhancement metrics in predicting the Fuhrman grade of clear cell RCC.Materials and methods65 multiphase CT examinations with clear cell RCCs were utilized, 44 tumors with Fuhrman grades 1 or 2 and 21 tumors with grades 3 or 4. After tumor segmentation, the following data were extracted: histogram analysis of voxel-based whole lesion attenuation in each phase, enhancement and washout using mean, median, skewness, kurtosis, standard deviation, and interquartile range.ResultsStatistically significant difference was observed in 4 measured parameters between grades 1–2 and grades 3–4: interquartile range of nephrographic attenuation values, standard deviation of absolute enhancement, as well as interquartile range and standard deviation of residual nephrographic enhancement. Interquartile range of nephrographic attenuation values was 292.86 HU for grades 1–2 and 241.19 HU for grades 3–4 (p value 0.02). Standard deviation of absolute enhancement was 41.26 HU for grades 1–2 and 34.66 HU for grades 3–4 (p value 0.03). Interquartile range was 297.12 HU for residual nephrographic enhancement for grades 1–2 and 235.57 HU for grades 3–4 (p value 0.02), and standard deviation of the same was 42.45 HU for grades 1–2 and 37.11 for grades 3–4 (p value 0.04).ConclusionOur results indicate that absolute enhancement is more heterogeneous for lower grade tumors and that attenuation and residual enhancement in nephrographic phase is more heterogeneous for lower grade tumors. This represents an important step in devising a predictive non-invasive model to predict the nucleolar grade.

Active Surveillance of Small Renal Masses: A Review on the Role of Imaging With a Focus on Growth Rate.

Objective This study aimed to systematically summarize the current literature in the field of active surveillance for small renal masses, with the primary focus being the role of imaging in the primary decision-making and subsequent follow-up. Materials A systematic review of the electronic databases PubMed and Web of Knowledge was performed according to Preferred Reporting Items for Systematic Reviews and Meta-analysis statement guidelines. Variables were extracted from the data set and included the following: (1) patient demographics, (2) tumor characteristics, and (3) study design. Results Twenty-one articles studying imaging in active surveillance of small renal masses were selected. Seventy-two percent (15/21) of studies were retrospective; 19% (4/21) were prospective; and 9% (2/21) studies were bidirectional. Mean age of patients was 69 years (range, 57–81 years). A total of 1386 patients were in the study; 59% of patients were men. Mean follow-up was 39 months (range, 18.8–91.5 months). Sixty-seven percent of masses discussed in this review were followed up using more than one imaging modality; 19% consistently used computed tomography for follow-up whereas the remaining 14% did not specify what imaging modality was used. Imaging studies were reviewed by the investigators centrally in 86% (18/21). In 14% of the studies, only imaging report was reviewed. Biopsy was performed in 24% of masses. Mean growth rate for all tumors was 0.27 cm/y (range, 0.06–0.7 cm/y). For studies where growth rate of benign and malignant masses were differentiated, mean growth rate for benign masses was 0.3 cm/y and mean growth rate for malignant masses was 0.35 cm/y. Conclusions Growth rate is often used as a discriminant in following up a small renal mass in patients undergoing active surveillance. However, there is great variability in growth rate and it alone is not an adequate marker for determining whether the tumor is malignant. Because very few studies specified radiological characteristics of small renal masses, future studies can be done to better characterize masses.

Intra-arterial contrast-enhanced ultrasound (IA CEUS) for localization of hepatocellular carcinoma (HCC) supply during transarterial chemoembolization (TACE): a case series

Transarterial chemoembolization (TACE) is a proven catheter-based locoregional therapy for treatment of hepatocellular carcinoma (HCC). Drug-eluting bead TACE involves delivering micrometer-sized particles preloaded with doxorubicin directly to the tumor via its arterial blood supply and results in vascular embolization with intra-tumoral drug release. Effective therapy requires mapping of the tumor arterial supply, which in some cases cannot be accomplished with conventional angiographic techniques alone. Contrast-enhanced ultrasound (CEUS) is an imaging technique which utilizes microbubble contrast agents to demonstrate blood flow and tissue perfusion, enabling tumor visualization in real time. CEUS with intravenous contrast administration is well established for evaluation of HCC. Intra-arterial (IA) CEUS, on the other hand, is an emerging technique that allows more selective evaluation of the arterial supply to the tumor. The three cases in this report illustrate the utility of intra-procedural IA CEUS during TACE. Specifically, IA CEUS aided TACE in cases where the HCC showed poor arterial enhancement, an extrahepatic arterial supply, and a portal venous supply, respectively.

Cross-sectional imaging following surgical interventions for stress urinary incontinence in females

Stress urinary incontinence (SUI) is a condition in which the weakness of the pelvic floor muscles causes unintentional loss of urine. For patients who are unable to achieve symptomatic improvement from lifestyle modification and pharmacotherapy, surgical placement of the pelvic slings or the use of urethral bulking agents has been shown to provide tremendous symptomatic improvement. Learning to recognize the pelvic slings and to identify their complications on imaging is invaluable; however, this is challenging because of the change in the local anatomy after surgical placement of the sling. In this paper, we present CT and MR imaging to demonstrate the surgical and non-surgical treatments of female SUI and their complications. Through this pictorial essay, our goal is to familiarize radiologists with recognizing the various forms of treatment for SUIs, the relevant pelvic anatomy, and complications that may occur secondary to the surgical placement of the pelvic slings.

Composite liver tumors: a radiologic-pathologic correlation

Bi-phenotypic neoplasm refers to tumors derived from a common cancer stem cell with unique capability to differentiate histologically into two distinct tumor types. Bi-phenotypic hepatocellular carcinoma-cholangiocarcinoma (HCC-CC), although a rare tumor, is important for clinicians to recognize, since treatment options targeting both elements of the tumor are crucial. Imaging findings of bi-phenotypic HCC-CC are not specific and include features of both HCC and CC. A combination of imaging and immuno-histochemical analysis is usually needed to make the diagnosis.

Atypical central neurocytoma with metastatic craniospinal dissemination: a case report.

Central neurocytomas comprise nearly half of adult intraventricular neoplasms. The median age of onset is 34 years. It is typically a low-grade neoplasm (World Health Organization grade II), although some cases of malignant neurocytomas have been described. We present a rare case of an atypical central neurocytoma with craniospinal dissemination, including both imaging and pathologic findings.

Multidimensional Interactive Radiology Report and Analysis: standardization of workflow and reporting for renal mass tracking and quantification

A conventional radiology report primarily consists of a large amount of unstructured text, and lacks clear, concise, consistent and content-rich information. Hence, an area of unmet clinical need consists of developing better ways to communicate radiology findings and information specific to each patient. Here, we design a new workflow and reporting system that combines and integrates advances in engineering technology with those from the medical sciences, the Multidimensional Interactive Radiology Report and Analysis (MIRRA). Until recently, clinical standards have primarily relied on 2D images for the purpose of measurement, but with the advent of 3D processing, many of the manually measured metrics can be automated, leading to better reproducibility and less subjective measurement placement. Hence, we make use this newly available 3D processing in our workflow. Our pipeline is used here to standardize the labeling, tracking, and quantifying of metrics for renal masses.