Imaging findings during and after percutaneous cryoablation of hepatic tumors.

Objective: Imaging plays a key role in the assessment of patients before, during, and after percutaneous cryoablation of hepatic tumors. Intra-procedural and early post-procedure imaging with CT and MRI is vital to the assessment of technical success including adequacy of ablation zone coverage. Recognition of the normal expected post-procedure findings of hepatic cryoablation such as ice ball formation, hydrodissection, and the normal appearance of the ablation zone is crucial to be able to differentiate from complications including vascular, biliary, or non-target organ injury.

Acute Nonhemorrhagic Adrenal Infarction in Pregnancy: 10-Year MRI Incidence and Patient Outcomes at a Single Institution.

Objective: The purpose of this study was to retrospectively investigate the MRI incidence of nonhemorrhagic adrenal infarction in pregnant women undergoing MRI evaluation of acute abdominal or flank pain, assess the MRI features quantitatively, and report patient outcomes.

Materials And Methods: All abdominal MRI examinations of pregnant women with acute pain at one institution from May 2005 to April 2015 were reviewed. The adrenals were evaluated for abnormal morphologic and signal intensity characteristics described in the literature characterizing nonhemorrhagic adrenal infarction and were compared with the contralateral adrenal by paired t tests.

Percutaneous Image-Guided Cryoablation of Hepatic Tumors: Single-Center Experience With Intermediate to Long-Term Outcomes.

Objective: The purpose of this article is to report our intermediate to long-term outcomes with image-guided percutaneous hepatic tumor cryoablation and to evaluate its technical success, technique efficacy, local tumor progression, and adverse event rate.

Materials And Methods: Between 1998 and 2014, 299 hepatic tumors (243 metastases and 56 primary tumors; mean diameter, 2.5 cm; median diameter, 2.

Hepatobiliary phase MRI: impact on planning image-guided liver tumor ablations.

Purpose: To assess the impact of hepatobiliary phase images obtained during intravenous gadoxetate disodium-enhanced liver MRI in the planning of image-guided liver tumor ablations.

Methods: This institutional review board-approved retrospective study included 34 patients (21 men, 13 women, ages 25-80) who underwent 36 liver MRI examinations with gadoxetate disodium within 12 weeks prior to image-guided thermal ablation of 62 liver tumors during 36 procedures. Visibility of bile ducts, subdivided by branch order, on hepatobiliary phase images was compared to standard MRI sequence images by an attending abdominal radiologist and fellow.

Cross-sectional imaging of congenital and acquired abnormalities of the portal venous system.

Knowing the normal anatomy, variations, congenital and acquired pathologies of the portal venous system are important, especially when planning liver surgery and percutaneous interventional procedures. The portal venous system pathologies can be congenital such as agenesis of portal vein (PV) or can be involved by other hepatic disorders such as cirrhosis and malignancies. In this article, we present normal anatomy, variations, and acquired pathologies involving the portal venous system as seen on computed tomography (CT) and magnetic resonance imaging (MRI).

Hepatic Microwave Ablation Zone Size: Correlation with Total Energy, Net Energy, and Manufacturer-Provided Chart Predictions.

Purpose: To determine whether total energy (TE) reaching the microwave (MW) applicator or net energy (NE) exiting the applicator (after correcting for reflectivity) correlates better with hepatic MW ablation zone dimensions than manufacturer-provided chart predictions.

Materials And Methods: Single-applicator, nonoverlapping ablations of 93 liver tumors (0.7-5.

Incidence and clinical sequelae of portal and hepatic venous thrombosis following percutaneous cryoablation of liver tumors.

Purpose: To assess the incidence and sequelae of portal and hepatic venous thrombosis after percutaneous cryoablation of hepatic tumors.

Methods: From November 1998 through December 2010, 223 hepatic tumors were cryoablated during 170 ablation procedures in 135 patients. 24-h post-procedure MR images were reviewed retrospectively by two abdominal radiologists in consensus to identify tumor ablations that developed one or more new portal or hepatic venous thromboses in or outside the ablation zone.

Three-dimensional quantitative assessment of ablation margins based on registration of pre- and post-procedural MRI and distance map.

Purpose: Contrast-enhanced MR images are widely used to confirm the adequacy of ablation margin after liver ablation for early prediction of local recurrence. However, quantitative assessment of the ablation margin by comparing pre- and post-procedural images remains challenging. We developed and tested a novel method for three-dimensional quantitative assessment of ablation margin based on non-rigid image registration and 3D distance map.

Catecholamine Surge during Image-Guided Ablation of Adrenal Gland Metastases: Predictors, Consequences, and Recommendations for Management.

Purpose: To identify retrospectively predictors of catecholamine surge during image-guided ablation of metastases to the adrenal gland.

Materials And Methods: Between 2001 and 2014, 57 patients (39 men, 18 women; mean age, 65 y ± 10; age range, 41-81 y) at two academic medical centers underwent ablation of 64 metastatic adrenal tumors from renal cell carcinoma (n = 27), lung cancer (n = 23), melanoma (n = 4), colorectal cancer (n = 3), and other tumors (n = 7). Tumors measured 0.

Radiation dose during CT-guided percutaneous cryoablation of renal tumors: Effect of a dose reduction protocol.

Purpose: To estimate and compare the radiation dose using a standard protocol and that of a dose reduction protocol in patients undergoing CT-guided percutaneous cryoablation of renal tumors.

Materials And Methods: An IRB-approved, HIPAA-compliant retrospective study of 97 CT-guided cryoablation procedures to treat a solitary renal tumor in each of 97 patients (64 M, 33 F; range 31-84 yrs) was performed. Fifty patients were treated using a standard dose protocol (kVp=120, mean mAs=180, monitoring scans every 3 min during freezes), and an additional 47 patients were treated using a dose reduction protocol (kVp=100, mean mAs=100, monitoring scans less frequently than every 3 min during freezes).

Nonhemorrhagic Adrenal Infarction With Magnetic Resonance Imaging Features During Pregnancy.

Background: Adrenal infarction is an infrequent cause of severe abdominal pain during pregnancy. The magnetic resonance imaging (MRI) features of adrenal infarction have not previously been thoroughly described.

Cases: A 20-year-old woman, gravida 1 para 0, presented at 27 4/7 weeks of gestation with sudden-onset right upper quadrant and flank pain.

Graphics Processing Unit-Accelerated Nonrigid Registration of MR Images to CT Images During CT-Guided Percutaneous Liver Tumor Ablations.

Rationale And Objectives: Accuracy and speed are essential for the intraprocedural nonrigid magnetic resonance (MR) to computed tomography (CT) image registration in the assessment of tumor margins during CT-guided liver tumor ablations. Although both accuracy and speed can be improved by limiting the registration to a region of interest (ROI), manual contouring of the ROI prolongs the registration process substantially. To achieve accurate and fast registration without the use of an ROI, we combined a nonrigid registration technique on the basis of volume subdivision with hardware acceleration using a graphics processing unit (GPU).

MRI in local staging of rectal cancer: an update.

Preoperative imaging for staging of rectal cancer has become an important aspect of current approach to rectal cancer management, because it helps to select suitable patients for neoadjuvant chemoradiotherapy and determine the appropriate surgical technique. Imaging modalities such as endoscopic ultrasonography, computed tomography, and magnetic resonance imaging (MRI) play an important role in assessing the depth of tumor penetration, lymph node involvement, mesorectal fascia and anal sphincter invasion, and presence of distant metastatic diseases. Currently, there is no consensus on a preferred imaging technique for preoperative staging of rectal cancer.

Percutaneous cryoablation of hepatic tumors adjacent to the gallbladder: assessment of safety and effectiveness.

Purpose: To assess safety and effectiveness of percutaneous image-guided cryoablation of hepatic tumors adjacent to the gallbladder.

Materials And Methods: Twenty-one cryoablation procedures were performed to treat 19 hepatic tumors (mean size, 2.7 cm; range, 1.

CT-guided percutaneous cryoablation of central lung tumors.

Purpose: Cryoablation has been successfully used to treat lung tumors. However, the safety and effectiveness of treating tumors adjacent to critical structures has not been fully established. We describe our experience with computed tomography (CT)-guided percutaneous cryoablation of central lung tumors and the role of ice ball monitoring.

Contrast-enhanced CT and MR imaging of renal vessels.

In the evaluation of renal vessels, the accepted diagnostic gold standard digital subtraction angiography is now being challenged by state of the art CT and MR imaging. Currently in many centers, cross-sectional imaging modalities are being used as a first line diagnostic tool to evaluate arterial and venous system of the kidneys and conventional angiography has been reserved only for therapeutic intervention. CT and MR imaging display not only the lumen of the vessel as in conventional angiography, but also allow the visualization of the vessel wall, renal parenchyma, collecting system, and other adjacent soft tissue structures.

Percutaneous imaging-guided cryoablation of liver tumors: predicting local progression on 24-hour MRI.

Objective: The purpose of this study was to determine which MRI features observed 24 hours after technically successful percutaneous cryoablation of liver tumors predict subsequent local tumor progression and to describe the evolution of imaging findings after cryoablation.

Materials And Methods: Thirty-nine adult patients underwent technically successful imaging-guided percutaneous cryoablation of 54 liver tumors (hepatocellular carcinoma, 8; metastases, 46). MRI features pertaining to the tumor, ablation margin, and surrounding liver 24 hours after treatment were assessed independently by two readers.

Percutaneous treatment of hepatocellular carcinoma in patients with cirrhosis: a comparison of the safety of cryoablation and radiofrequency ablation.

Purpose: To compare the safety of image-guided percutaneous cryoablation and radiofrequency ablation in the treatment of hepatocellular carcinoma in patients with cirrhosis.

Materials And Methods: This retrospective HIPAA-compliant study received institutional review board approval. Forty-two adult patients with cirrhosis underwent image-guided percutaneous ablation of hepatocellular carcinoma from 2003 to 2011.

Renal transplant complications: diagnostic and therapeutic role of radiology.

Kidney was the first and is the most frequently transplanted organ. Despite improved surgical techniques and transplantation technology, complications do occur and, if left untreated, may lead to catastrophic consequences. Renal transplantation complications may be vascular (eg, renal artery and vein stenosis and thrombosis, arteriovenous fistula, and pseudoaneurysms); urologic (eg, urinary obstruction and leak, and peritransplantation fluid collections, including hematoma, seroma, lymphocele, and abscess formation); and nephrogenic, including acute tubular necrosis, graft rejection, chronic allograft nephropathy, and neoplasm.

The use of cryoablation in treating liver tumors.

Percutaneous image-guided tumor ablation techniques have been used as an alternative method for patients with unresectable liver tumors. Although all techniques avoid morbidity and mortality of major surgery and have advantage of preserving non-tumoral liver parenchyma, cryoablation currently is the only percutaneous ablation technique allowing intraprocedural monitoring because of visibility of its ablation effect with computed tomography and MRI. Cryoablation uses extremely low temperatures to induce local tissue necrosis to treat both primary and metastatic liver tumors.

Successful percutaneous radiologic management of renal cell carcinoma tumor seeding caused by percutaneous biopsy performed before ablation.

A case is reported of the successful image-based detection, diagnosis, and percutaneous ablation of tumor seeding in a 61-year-old man that was caused by percutaneous biopsy of a renal cell carcinoma performed before cryoablation and was not detected until 4 years after the biopsy procedure. Although tumor seeding is a rare complication after percutaneous biopsy or ablation, this case emphasizes the importance of imaging surveillance of the needle tract used during both biopsy and ablation procedures, provides guidance on measures that can be used to minimize the occurrence of tumor seeding, and demonstrates that entirely radiologic management can be successful.

MRI assessment of percutaneous ablation of liver tumors: value of subtraction images.

Purpose: To evaluate the value of subtraction images when using MRI to assess liver tumors treated with percutaneous ablation.

Materials And Methods: Following percutaneous ablation of 35 liver tumors, two abdominal radiologists, blinded to outcomes, independently reviewed follow-up MRI examinations for tumoral enhancement suggestive of residual/recurrent tumor and rated their confidence level. After one year, the readers reviewed the same examinations with added subtraction images.

Imaging features of bone metastases in patients with gastrointestinal stromal tumors.

Purpose: To determine the prevalence and imaging features of bone metastases in patients with gastrointestinal stromal tumors (GISTs).

Materials And Methods: The medical records of 190 patients with pathologically proven GISTs were reviewed, and patients with bone metastases were identified. Computed tomography (CT) scans of the chest, abdomen, and pelvis were examined for features of bone metastases, and findings were correlated with the results of positron-emission tomography (PET) and histopathology.

Radiofrequency ablation: technique and clinical applications.

Radiofrequency ablation is the most commonly used percutaneous ablation technique and well-documented in the literature on focal therapies. It has become the image-guided ablation method of choice because of its efficacy, safety, and ease of use. Radiofrequency ablation has shown promise in treating selected solid tumors, particularly those involving the liver, kidneys, lungs, and the musculoskeletal system.