Feasibility and safety of bipolar radiofrequency track cautery during percutaneous image-guided abdominal biopsy procedures.

PURPOSE: The purpose of this study was to assess the feasibility and safety of using a bipolar radiofrequency track cautery device during percutaneous image-guided abdominal biopsy procedures in at-risk patients. METHODS: Forty-two patients (26-79 years old; female 44%) with at least one bleeding risk factor who underwent an abdominal image-guided (CT or US) biopsy and intended bipolar radiofrequency track cautery (BRTC) were retrospectively studied. An 18G radiofrequency electrode was inserted through a 17G biopsy introducer needle immediately following coaxial 18G core biopsy, to cauterize the biopsy track using temperature control. Bleeding risk factors, technical success, and adverse events were recorded. RESULTS: BRTC was technically successful in 41/42 (98%) of procedures; in one patient, the introducer needle retracted from the liver due to respiratory motion prior to BRTC. BRTC following percutaneous biopsy was applied during 41 abdominal biopsy procedures (renal mass = 12, renal parenchyma = 10, liver mass = 9, liver parenchyma = 5, splenic mass or parenchyma = 4, gastrohepatic mass = 1). All patients had one or more of the following risk factors: high-risk organ (spleen or renal parenchyma), hypervascular mass, elevated prothrombin time, renal insufficiency, thrombocytopenia, recent anticoagulation or anticoagulation not withheld for recommended interval, cirrhosis, intraprocedural hypertension, brisk back bleeding observed from the introducer needle, or subcapsular tumor location. No severe adverse events (grade 3 or higher) occurred. Two (2/41, 5%) mild (grade 1) bleeding events did not cause symptoms or require intervention. CONCLUSION: Bipolar radiofrequency track cautery was feasible and safe during percutaneous image-guided abdominal biopsy procedures. IRB approval: MBG 2022P002277.

Integration of fully automated computer-aided pulmonary nodule detection into CT pulmonary angiography studies in the emergency department: effect on workflow and diagnostic accuracy.

PURPOSE: To assess the feasibility of implementing fully automated computer-aided diagnosis (CAD) for detection of pulmonary nodules on CT pulmonary angiography (CTPA) studies in emergency setting. MATERIALS AND METHODS: CTPA of 48 emergency patients was retrospectively reviewed. Fully automated CAD nodule detection was performed at the scanner and results were automatically submitted to PACS. A third-year radiology resident (RAD1) and a cardiothoracic radiologist with 6 years' experience (RAD2) reviewed the scans independently to detect pulmonary nodules in two different sessions 8 weeks apart: session 1, CAD was reviewed first and then all images were reviewed; session 2, CAD was reviewed last after all images were reviewed. Time spent by RAD to evaluate image sets was measured for each case. Fisher's exact test and t test were used. RESULTS: There were 17 male and 31 female patients with mean ± SD age of 48.7 ± 16.4 years. Using CAD at the beginning was associated with lower average reading time for both readers. However, difference in reading time did not reach statistical significance for RAD1 (RAD1 94.6 s vs. 102.7 s, P > 0.05; RAD2 61.1 s vs. 76.5 s, P < 0.05). Using CAD at the end significantly increased rate of RAD1 and RAD2 nodule detection by 34% (2.52 vs. 2.12 nodule/scan, P < 0.05) and 27% (2.23 vs. 1.81 nodule/scan, P < 0.05), respectively. CONCLUSION: Routine utilization of CAD in emergency setting is feasible and can improve detection rate of pulmonary nodules significantly. Different methods of incorporating CAD in detecting pulmonary nodules can improve both the rate of detection and interpretation speed.

Tricky Findings in Liver Transplant Imaging: A Review of Pitfalls With Solutions.

Orthotopic liver transplantation is the preferred treatment for end-stage liver disease. Imaging plays an important role in the follow-up of transplant recipients by identifying a variety of complications. Posttransplant liver imaging can be challenging with altered vascular and nonvascular postoperative findings closely mimicking pathologies. A thorough knowledge of these common imaging findings in a posttransplant liver is essential for the radiologist to avoid erroneous diagnoses and unnecessary workup. We focus on such imaging findings and provide tips to avoid misinterpretation.

Current Guidelines for the Diagnosis and Management of Hepatocellular Carcinoma: A Comparative Review.

OBJECTIVE: The purpose of this article is to review aspects of guidelines pertinent to radiologists involved in the diagnosis or treatment of hepatocellular carcinoma. CONCLUSION: Early diagnosis and treatment of hepatocellular carcinoma are important because only 10% of patients meet the criteria for curative therapy at the time of diagnosis. Several organizations have developed guidelines for screening, diagnosis, and treatment of hepatocellular carcinoma. Radiologists play a pivotal role in every aspect of these guidelines.

Threshold for Enhancement in Treated Hepatocellular Carcinoma on MDCT: Effect on Necrosis Quantification.

OBJECTIVE: The objective of our study was to determine whether the conventionally used enhancement threshold of 10 HU for assessing tumor viability in treated hepatocellular carcinoma (HCC) lesions is valid. MATERIALS AND METHODS: To distinguish pseudoenhancement from enhancement in a tumor, we used an in vivo model: The attenuation of 54 hepatic cysts during the unenhanced and portal venous phases of MDCT, similar to what may be observed in HCC with central necrosis, was used to determine the threshold for pseudoenhancement. To validate this model, we compared the attenuation value of liver parenchyma in this cohort with that of 22 HCCs during the late arterial phase of enhancement. We tested the effect of this pseudoenhancement on quantifying necrosis in HCC compared with the conventionally used threshold of 10 HU. RESULTS: Values of enhancing HCC tissue on arterial phase MDCT (mean, 121.3 HU) were comparable with normal liver parenchyma on venous phase MDCT (117.3 HU) (p = 0.27). The threshold of 17.1 HU was the best threshold for the detection of pseudoenhancement in cysts (99% accuracy, 100% sensitivity, and 98% specificity). When this threshold was used instead of the conventional threshold of 10 HU, the mean necrosis proportion of treated HCC increased from 34.0% to 42.6% and the mean viable tumor proportion decreased from 66.0% to 57.4%. The quantification of viable HCC tissue based on 10 HU and the quantification of viable HCC tissue based on 17.1 HU were found to be significantly different (p < 0.0001). CONCLUSION: The threshold of 17.1 HU may be the appropriate cutoff for nonenhancement in a necrotic HCC. Use of this threshold may potentially affect how response to therapy is quantified and categorized.

CT of the Abdomen with Reduced Tube Voltage in Adults: A Practical Approach.

Recent innovations in computed tomographic (CT) hardware and software have allowed implementation of low tube voltage imaging into everyday CT scanning protocols in adults. CT at a low tube voltage setting has many benefits, including (a) radiation dose reduction, which is crucial in young patients and those with chronic medical conditions undergoing serial CT examinations for disease management; and (b) higher contrast enhancement. For the latter, increased attenuation of iodinated contrast material improves the evaluation of hypervascular lesions, vascular structures, intestinal mucosa in patients with bowel disease, and CT urographic images. Additionally, the higher contrast enhancement may provide diagnostic images in patients with renal dysfunction receiving a reduced contrast material load and in patients with suboptimal peripheral intravenous access who require a lower contrast material injection rate. One limitation is that noisier images affect image quality at a low tube voltage setting. The development of denoising algorithms such as iterative reconstruction has made it possible to perform CT at a low tube voltage setting without compromising diagnostic confidence. Other potential pitfalls of low tube voltage CT include (a) photon starvation artifact in larger patients, (b) accentuation of streak artifacts, and (c) alteration of the CT attenuation value, which may affect evaluation of lesions on the basis of conventional enhancement thresholds. CT of the abdomen with a low tube voltage setting is an excellent radiation reduction technique when properly applied to imaging of select patients in the appropriate clinical setting.

Performance of tumor growth kinetics as an imaging biomarker for response assessment in colorectal liver metastases: correlation with FDG PET.

PURPOSE: To correlate RECIST, volumetric criteria, and tumor growth kinetics at multidetector-computed tomography with tumor metabolic activity at FDG PET in colorectal liver metastases (CRCLM) treated with bevacizumab-based chemotherapy. METHODS: Thirty-two CRCLM in 20 patients treated with bevacizumab-based chemotherapy were evaluated. Pre- and post-treatment CT scans were used to calculate reciprocal of doubling time (RDT), percentage change in the lesion's longest transaxial diameter (RECIST 1.1), and percentage change in the tumor volume. The accuracy of these parameters in predicting response based on standard uptake value analysis at FDG PET was assessed. Data were analyzed using Spearman's correlation, student's t, Mann-Whitney, Wilcoxon signed-rank, and Fisher's exact tests. RESULTS: According to FDG PET, 24/32 (75%) lesions were categorized as responders and 8/32 (25%) lesions as nonresponders. Based on RDT, 26/32 (81.25%) lesions were classified as responders and 6/32 (18.75%) lesions as nonresponders. Response classification according to RDT and FDG PET was concordant in 30/32 (93.75%) lesions, whereas RECIST 1.1 and volumetric criteria were concordant with FDG PET for 20/32 (62.5%) and 21/32 (65.63%) lesions, respectively. A strong association was found between RDT and response based on FDG PET (odds ratio = 127.4; 95% CI 5.54-2997; P < 0.0001). CONCLUSIONS: Tumor growth kinetics may be an effective imaging biomarker for response evaluation in CRCLM.

CT of Atypical and Uncommon Presentations of Hepatocellular Carcinoma.

OBJECTIVE: The purpose of this article is to familiarize radiologists with uncommon presentations of hepatocellular carcinoma (HCC) with an emphasis on the CT spectrum of atypical appearances. CONCLUSION: HCC is the fifth most common neoplasm worldwide and the second most common cause of cancer-related death. In many cases, HCC can be confidently diagnosed with noninvasive imaging. However, there are numerous unusual appearances of HCC with which the radiologist must be familiar.

Reproducibility of mRECIST in assessing response to transarterial radioembolization therapy in hepatocellular carcinoma.

UNLABELLED: The purpose of our study was to evaluate the reproducibility of Modified Response Evaluation Criteria in Solid Tumors (mRECIST) in hepatocellular carcinoma (HCC) lesions undergoing transarterial radioembolization (TARE) therapy and to determine whether mRECIST reproducibility is affected by the enhancement pattern of HCC. One hundred and three HCC lesions from 103 patients treated with TARE were evaluated. The single longest diameter of viable tumor tissue was measured by two radiologists at baseline; response to therapy was evaluated according to mRECIST. The enhancement pattern of HCC lesions was correlated with their mRECIST response. The response rate between mRECIST and RECIST 1.1 was compared. Wilcoxon signed-rank test, paired t test, Lin's concordance correlation coefficient (ρc ), Bland-Altman plot, kappa statistics, and Fisher's exact test were used to assess intra- and interobserver reproducibilities and to compare response rates. There were better intra- than interobserver agreements in the measurement of single longest diameter of viable tumor tissue (bias = 0 cm intraobserver versus bias = 0.3 cm interobserver). For mRECIST, good intraobserver (ĸ = 0.70) and moderate interobserver (ĸ = 0.56) agreements were noted. The mRECIST response for HCC lesions with homogeneous enhancement at both baseline and follow-up imaging showed better intra- and interobserver agreements (ĸ = 0.77 and 0.60, respectively) than lesions with heterogeneous enhancement at both scans (ĸ = 0.54 and 0.40, respectively). In the early follow-up period mRECIST showed a significantly higher response rate than RECIST (40.8% versus 3.9%; P = 0.025). CONCLUSIONS: In HCC patients treated with TARE, mRECIST captures a significantly higher response rate compared with RECIST; it also demonstrates acceptable intra- and interobserver reproducibilities for HCC lesions treated with TARE, and mRECIST reproducibility may be lower for HCC lesions with heterogeneous distribution of the viable tumor tissue.

Tumor growth kinetics versus RECIST to assess response to locoregional therapy in breast cancer liver metastases.

RATIONALE AND OBJECTIVES: The aim of our study was to evaluate changes in growth kinetics of breast cancer liver metastasis in response to locoregional therapy and compare them to Response Evaluation Criteria in Solid Tumors (RECIST). MATERIALS AND METHODS: This Health Insurance Portability and Accountability Act-compliant retrospective study was Institutional Review Board approved. Thirty-four chemorefractory breast cancer liver metastases from 21 patients treated with yttrium-90 ((90)Y) were evaluated. Pre- and posttreatment computed tomography (CT) scans were used to calculate tumor growth kinetics. The growth parameter analyzed was reciprocal of doubling time (RDT). RDT range for stable disease (SD) was defined by the measurement error rate. A negative RDT below the SD range defined response and was categorized as either partial response (PR) or complete response, whereas a positive RDT value above the SD range indicated progressive disease (PD). Comparison was made to tumor response classification according to percentage change in the lesion's maximal diameter per RECIST. Lin's concordance correlation coefficient, Bland-Altman plot, Wilcoxon signed rank test, and Student t test were used for analysis. Significance was set at 0.05. RESULTS: RDT range for SD ranged from -0.46 to +2.17. Six lesions with PR based on RECIST showed PR based on their volumetric growth rate (mean RDT of -17.3 ± 2.6). Similarly, one lesion with PD according to RECIST was categorized as PD based on its growth kinetics (RDT of 10.2). However, 14 (51.85%) lesions classified as SD by RECIST had PR according to growth kinetics (mean RDT of -7.8), six (22.22%) lesions were categorized as SD (mean RDT of 0.8), whereas seven (25.93%) lesions showed PD (mean RDT of 4.5). Growth kinetic parameters were significantly different for lesions with PR when compared to lesions with PD (P < .0001). CONCLUSIONS: In patients with breast cancer liver metastases undergoing locoregional therapy, RECIST categorization may not be an accurate reflection of treatment response.

The combined effect of multidetector-row computed tomographic tube voltage, tube current, and image reconstruction algorithm on the detection of pneumothorax after intervention.

OBJECTIVES: The objective of the study was to determine the lowest multidetector-row computed tomographic radiation dose parameters for the detection of pneumothorax after thoracic intervention. MATERIALS AND METHODS: An anthropomorphic chest phantom containing pneumothoraces was imaged with different tube voltages (80, 100, and 120 kV[p]) and tube currents (10, 20, 40, 75, and 110 mAs). The images were reconstructed with both filtered back projection (FBP) and iterative reconstruction (IR) algorithms. Two blinded radiologists scored images independently for the presence or absence of pneumothorax. Effective dose, image noise, contrast-to-noise ratio, and signal-to-noise ratio were recorded. RESULTS: At radiation dose below 0.48 mSv, sensitivity for the detection of pneumothorax decreased in both reconstruction algorithms (80% for FBP vs 83% for IR; P > 0.05). Interobserver agreement was good (k = 0.78). The IR data sets showed lower image noise as well as higher signal-to-noise ratio and contrast-to-noise ratio when compared with FBP on all acquisition parameters (P < 0.0001). CONCLUSIONS: Very low computed tomographic dose parameters may be suitable for confident detection of small pneumothoraces after intervention.

Cross-sectional imaging of perforated gallbladder.

Gallbladder perforation is a potentially life-threatening condition commonly seen as a complication of acute cholecystitis. Urgent surgical intervention is often needed to reduce serious morbidity and mortality. It presents a diagnostic challenge due to nonspecific symptoms, leading to a delay in diagnosis. Imaging plays a vital role in early identification of this potentially fatal condition and evaluation by more than one imaging modality may be required to make the diagnosis. Knowledge of specific and ancillary imaging findings is crucial to avoid misdiagnosis. In this article, we will review the risk factors, pathophysiology, and surgical classification of gallbladder perforation and discuss the role of multimodality imaging in its diagnosis. Differential diagnoses on imaging will also be discussed.