Machine Learning for Adrenal Gland Segmentation and Classification of Normal and Adrenal Masses at CT.

Background Adrenal masses are common, but radiology reporting and recommendations for management can be variable. Purpose To create a machine learning algorithm to segment adrenal glands on contrast-enhanced CT images and classify glands as normal or mass-containing and to assess algorithm performance. Materials and Methods This retrospective study included two groups of contrast-enhanced abdominal CT examinations (development data set and secondary test set). Adrenal glands in the development data set were manually segmented by radiologists. Images in both the development data set and the secondary test set were manually classified as normal or mass-containing. Deep learning segmentation and classification models were trained on the development data set and evaluated on both data sets. Segmentation performance was evaluated with use of the Dice similarity coefficient (DSC), and classification performance with use of sensitivity and specificity. Results The development data set contained 274 CT examinations (251 patients; median age, 61 years; 133 women), and the secondary test set contained 991 CT examinations (991 patients; median age, 62 years; 578 women). The median model DSC on the development test set was 0.80 (IQR, 0.78-0.89) for normal glands and 0.84 (IQR, 0.79-0.90) for adrenal masses. On the development reader set, the median interreader DSC was 0.89 (IQR, 0.78-0.93) for normal glands and 0.89 (IQR, 0.85-0.97) for adrenal masses. Interreader DSC for radiologist manual segmentation did not differ from automated machine segmentation (P = .35). On the development test set, the model had a classification sensitivity of 83% (95% CI: 55, 95) and specificity of 89% (95% CI: 75, 96). On the secondary test set, the model had a classification sensitivity of 69% (95% CI: 58, 79) and specificity of 91% (95% CI: 90, 92). Conclusion A two-stage machine learning pipeline was able to segment the adrenal glands and differentiate normal adrenal glands from those containing masses. © RSNA, 2022 Online supplemental material is available for this article.

Can 3-Phase Computed Tomography Urography Be Used to Characterize Adrenal Nodules? Results in 145 Patients.

OBJECTIVE: The aim of the study is to determine whether computed tomography (CT) urography (CTU) can characterize incidental adrenal nodules. METHODS: This retrospective cohort study was performed at an academic medical center. Patients were identified by free text search of CTU reports that contained the terms "adrenal mass" "adrenal nodule" and "adrenal lesion." Computed tomography urography technique consisted of unenhanced images and postcontrast images obtained at 100 seconds and 15 minutes. The final cohort included 145 patients with 151 adrenal nodules. Nodules were considered lipid-rich adenomas or myelolipomas based on unenhanced imaging characteristics. Absolute and relative washout values were calculated for the remaining nodules, using a cutoff of 60% and 40%, respectively, to diagnose adenomas. Reference standard for lipid-poor adenomas and malignant nodules was histopathology or imaging/clinical follow-up. Mann-Whitney U test was used for comparison of continuous variables, and Fisher exact test was used for categorical variables. RESULTS: One hundred nodules were lipid-rich adenomas and 3 were myelolipomas. Forty-eight nodules were indeterminate at unenhanced CT, corresponding to 39 lipid-poor adenomas and 9 malignant nodules based on reference standards. Both absolute and relative washout correctly characterized 71% of nodules (34/48), with a sensitivity of 67% and specificity of 89%. Overall, 91% of all adrenal nodules (137/151) were correctly characterized by CTU alone. Lipid-poor adenomas were smaller than malignant nodules ( P < 0.01) and were lower in attenuation on unenhanced and delayed images ( P < 0.01). CONCLUSIONS: Adrenal nodules detected at 3-phase CTU can be accurately characterized, potentially eliminating the need for subsequent adrenal protocol CT or magnetic resonance imaging.

Should Renal Mass Biopsy Be Performed prior to or Concomitantly with Thermal Ablation?

PURPOSE: To determine diagnostic yield of renal biopsies performed in patients referred for image-guided tumor ablation (IGTA) and the frequency with which biopsy results would have obviated the need for subsequent ablation. MATERIALS AND METHODS: Retrospective review of an internal ablation database of a single institution revealed 401 consecutive percutaneous renal mass IGTAs performed from April 2000 to April 2015. Of 401 ablations, 32 were excluded, yielding 369 ablation events in 342 patients, which represented the study cohort. Patients were subdivided into groups according to whether or not biopsy was performed. Lesions were categorized according to size, malignancy/benignity, and pathology. RESULTS: IGTA was performed with biopsy for 317/369 (85.9%) and without biopsy for 52/369 (14.1%) lesions. Overall diagnostic yield for percutaneous biopsy was 94.3% (299/317). Based on biopsy results, 82.6% (262/317) were classified as malignant or suspicious, 9.5% (30/317) were classified as likely benign, and 2.2% (7/317) were classified as definitively benign. Only definitively benign lesions were designated as obviating the need for IGTA. IGTA was supported by biopsy results in the remaining 97.8% (310/317), including renal cell carcinomas, oncocytic neoplasms, metastases, and nondiagnostic biopsy results. CONCLUSIONS: Biopsy of renal masses with suspicious imaging features rarely (2.2%) obviated the need for IGTA. For patients who have undergone counseling and have elected to forgo active surveillance and surgical options, biopsy can safely be performed concomitantly with ablation.

Incidentally Detected Bilateral Adrenal Nodules in Patients Without Cancer: Is Further Workup Necessary?

OBJECTIVE: The purpose of this study was to determine the rate of malignancy in incidentally detected bilateral adrenal masses in patients with no known history of cancer. MATERIALS AND METHODS: A retrospective search of CT reports of patients with incidentally detected bilateral adrenal nodules was performed from January 1, 2002, to January 1, 2014. Patients were excluded if they had a known cancer or suspected functioning adrenal tumor; 161 patients were included. Nodules were characterized as benign or malignant on the basis of imaging features at the index CT examination, imaging features at subsequent adrenal protocol CT or MRI, imaging stability for a minimum of 1 year, or clinical follow-up of a minimum of 2 years. RESULTS: Mean nodule size was 1.8 cm (range, 0.7-4.9 cm). There were no cases of primary or secondary adrenal malignancy (95% CI, 0.00-0.023). The nodules diagnosed on index CT scans were 73 adrenal adenomas and two myelolipomas. Seventy-four nodules were subsequently characterized as adrenal adenomas on the basis of imaging findings. Of the 113 indeterminate nodules that had imaging follow-up, 111 were stable at the latest follow-up examination. One nodule grew 26% over 8.1 years, and the other grew 59% over 12.4 years. Clinical follow-up of patients with 60 indeterminate nodules revealed no evidence of adrenal malignancy. CONCLUSION: No case of malignancy was found in 322 incidentally detected bilateral adrenal nodules at CT of patients without known cancer. Imaging follow-up of such lesions may be unnecessary.

Automated Delivery of Clinical Follow-Up to the Radiologist via E-Mail: Feasibility Study of a New Information Technology Algorithm.

OBJECTIVE: The purposes of this study were to develop an automated process for radiologists to obtain clinical follow-up on radiology reports via HIPAA-compliant e-mail and to determine what follow-up data were collected and whether they were relevant to the radiology reports. CONCLUSION: The algorithm generated high-yield follow-up data for radiologists that may improve patient care by facilitating radiologist engagement and self-assessment.

Renal Cell Carcinoma: Comparison of RENAL Nephrometry and PADUA Scores with Maximum Tumor Diameter for Prediction of Local Recurrence after Thermal Ablation.

Purpose To evaluate the performance of the radius, exophytic or endophytic, nearness to collecting system or sinus, anterior or posterior, and location relative to polar lines (RENAL) nephrometry and preoperative aspects and dimensions used for anatomic classification (PADUA) scoring systems and other tumor biometrics for prediction of local tumor recurrence in patients with renal cell carcinoma after thermal ablation. Materials and Methods This HIPAA-compliant study was performed with a waiver of informed consent after institutional review board approval was obtained. A retrospective evaluation of 207 consecutive patients (131 men, 76 women; mean age, 71.9 years ± 10.9) with 217 biopsy-proven renal cell carcinoma tumors treated with thermal ablation was conducted. Serial postablation computed tomography (CT) or magnetic resonance (MR) imaging was used to evaluate for local tumor recurrence. For each tumor, RENAL nephrometry and PADUA scores were calculated by using imaging-derived tumor morphologic data. Several additional tumor biometrics and combinations thereof were also measured, including maximum tumor diameter. The Harrell C index and hazard regression techniques were used to quantify associations with local tumor recurrence. Results The RENAL (hazard ratio, 1.43; P = .003) and PADUA (hazard ratio, 1.80; P < .0001) scores were found to be significantly associated with recurrence when regression techniques were used but demonstrated only poor to fair discrimination according to Harrell C index results (C, 0.68 and 0.75, respectively). Maximum tumor diameter showed the highest discriminatory strength of any individual variable evaluated (C, 0.81) and was also significantly predictive when regression techniques were used (hazard ratio, 2.98; P < .0001). For every 1-cm increase in diameter, the estimated rate of recurrence risk increased by 198%. Conclusion Maximum tumor diameter demonstrates superior performance relative to existing tumor scoring systems and other evaluated biometrics for prediction of local tumor recurrence after renal cell carcinoma ablation. © RSNA, 2016.

Interreader Agreement of Prostate Imaging Reporting and Data System Version 2 Using an In-Bore MRI-Guided Prostate Biopsy Cohort: A Single Institution's Initial Experience.

OBJECTIVE: The purpose of this study is to determine the interobserver agreement of the Prostate Imaging Reporting and Data System version 2 (PI-RADSv2) for diagnosing prostate cancer using in-bore MRI-guided prostate biopsy as the reference standard. MATERIALS AND METHODS: Fifty-nine patients underwent in-bore MRI-guided prostate biopsy between January 21, 2010, and August 21, 2013, and underwent diagnostic multiparametric MRI 6 months or less before biopsy. A single index lesion per patient was selected after retrospective review of MR images. Three fellowship-trained abdominal radiologists (with 1-11 years' experience) blinded to clinical information interpreted all studies according to PI-RADSv2. Interobserver agreement was assessed using Cohen kappa statistics. RESULTS: Thirty-eight lesions were in the peripheral zone and 21 were in the transition zone. Cancer was diagnosed in 26 patients (44%). Overall PI-RADS scores were higher for all biopsy-positive lesions (mean ± SD, 3.9 ± 1.1) than for biopsy-negative lesions (3.1 ± 1.0; p < 0.0001) and for clinically significant lesions (4.2 ± 1.0) than for clinically insignificant lesions (3.1 ± 1.0; p < 0.0001). Overall suspicion score interobserver agreement was moderate (κ = 0.45). There was moderate interobserver agreement among overall PI-RADS scores in the peripheral zone (κ = 0.46) and fair agreement in the transition zone (κ = 0.36). CONCLUSION: PI-RADSv2 scores were higher in the biopsy-positive group. PI-RADSv2 showed moderate interobserver agreement among abdominal radiologists with no prior experience using the scoring system.

Effectiveness and safety of computed tomography-guided radiofrequency ablation of renal cancer: a 14-year single institution experience in 203 patients.

OBJECTIVES: To define effectiveness and safety of CT-guided radiofrequency ablation (RFA) of renal tumours and prognostic indicators for treatment success. METHODS: Patients with a single treatment of a solitary, biopsy-proven renal tumour with intent to cure over a 14-year period were included (n = 203). Probability of residual disease over time, complication rates and all-cause mortality were assessed in relation to multiple variables. RESULTS: Mean tumour size was 2.5 cm (range 1.0-6.0). Mean follow-up was 34.1 months (range 1-131). There was an increase in likelihood of residual disease for tumours ≥3.5 cm (P < 0.05), clear cell subtype of renal cell carcinoma (P ≤ 0.005) and maximum treatment temperature ≤70 °C (P < 0.05). There was a decrease in likelihood of residual disease for exophytic tumours (P = 0.01) and no difference based on age, gender, tumour location or type of radio freqency (RF) electrode used. Major complications occurred in 3.9 %. Median post-treatment survival was 7 years for patients with tumours <4 cm, and 5-year overall survival was 80 %. Probability of minor complication increased with tumour size (P = 0.03), as did all-cause mortality (P = 0.005). CONCLUSIONS: CT-guided RFA is safe and effective for early-stage renal cancer, particularly for exophytic tumours measuring <3.5 cm. Overall 5-year survival with tumours <4 cm is comparable to partial nephrectomy. KEY POINTS: • Prognostic indicators for success of CT-guided RFA of renal tumours are reported. • Tumour size ≥3.5 cm confers an increased risk for residual tumour. • Clear cell renal cell carcinoma subtype confers increased risk for residual tumour. • Tmax <70 °C within the ablation zone confers increased risk for residual tumour. • Exophytic tumours have a lower probability of residual disease.

CT Radiation: Key Concepts for Gentle and Wise Use.

Use of computed tomography (CT) in medicine comes with the responsibility of its appropriate (wise) and safe (gentle) application to obtain required diagnostic information with the lowest possible dose of radiation. CT provides useful information that may not be available with other imaging modalities in many clinical situations in children and adults. Inappropriate or excessive use of CT should be avoided, especially if required information can be obtained in an accurate and time-efficient manner with other modalities that require a lower radiation dose, or non-radiation-based imaging modalities such as ultrasonography and magnetic resonance imaging. In addition to appropriate use of CT, the radiology community also must monitor scanning practices and protocols. When appropriate, high-contrast regions and lesions should be scanned with reduced dose, but overly zealous dose reduction should be avoided for assessment of low-contrast lesions. Patients' cross-sectional body size should be taken into account to deliver lower radiation dose to smaller patients and children. Wise use of CT scanning with gentle application of radiation dose can help maximize the diagnostic value of CT, as well as address concerns about potential risks of radiation. In this article, key concepts in CT radiation dose are reviewed, including CT dose descriptors; radiation doses from CT procedures; and factors and technologies that affect radiation dose and image quality, including their use in creating dose-saving protocols. Also discussed are the contributions of radiation awareness campaigns such as the Image Gently and Image Wisely campaigns and the American College of Radiology Dose Index Registry initiatives.

How I do it: managing radiation dose in CT.

Computed tomography (CT) is an imaging test that is widely used worldwide to establish medical diagnoses and perform image-guided interventions. More recently, concern has been raised about the risk of carcinogenesis from medical radiation, with a focus on CT. The purpose of this article is to (a) describe the importance of educating radiology personnel, patients, and referring clinicians about the concerns over CT radiation, (b) describe commonly used CT parameters and radiation units, (c) discuss the importance of establishing a dedicated radiology team to manage CT radiation, and (d) describe specific CT techniques to minimize radiation while providing diagnostic examinations.

Clinical indications, safety, and effectiveness of percutaneous image-guided adrenal mass biopsy: an 8-year retrospective analysis in 160 patients.

PURPOSE: To assess indications, safety, and effectiveness of percutaneous adrenal mass biopsy in contemporary practice. METHODS: This institutional review board-approved, retrospective study included all patients undergoing percutaneous image-guided adrenal mass biopsies at an academic health system from January 6, 2015, to January 6, 2023. Patient demographics, biopsy indications, mass size, laboratory data, pathology results, and complications were recorded. Final diagnoses were based on pathology or ≥ 1 year of imaging follow-up when biopsy specimens did not yield malignant tissue. Test performance calculations excluded repeat biopsies. Continuous variables were compared with Student's t test, dichotomous variables with chi-squared test. RESULTS: A total of 160 patients underwent 186 biopsies. Biopsies were indicated to diagnose metastatic disease (139/186; 74.7%), for oncologic research only (27/186; 14.5%), diagnose metastatic disease and oncologic research (15/186; 8%), and diagnose an incidental adrenal mass (5/186; 2.7%). Biopsy specimens were diagnostic in 154 patients (96.3%) and non-diagnostic in 6 (3.8%). Diagnostic biopsies yielded malignant tissue (n = 136), benign adrenal tissue (n = 12), and benign adrenal neoplasms (n = 6) with sensitivity = 98.6% (136/138), specificity = 100% (16/16), positive predictive value = 100% (136/136), and negative predictive value = 88.9% (16/18). Adverse events followed 11/186 procedures (5.9%) and most minor (7/11, 63.6%). The adverse event rate was similar whether tissue was obtained for clinical or research purposes (10/144; 6.9% vs. 1/42; 2.4%, p = 0.27), despite more specimens obtained for research (5.8 vs. 3.7, p < 0.001). CONCLUSION: Percutaneous adrenal mass biopsy is safe, accurate, and utilized almost exclusively to diagnose metastatic disease or for oncologic research. The negative predictive value is high when diagnostic tissue samples are obtained. Obtaining specimens for research does not increase adverse event risk.

Reducing radiation dose at CT colonography: decreasing tube voltage to 100 kVp.

PURPOSE: To assess the effect of a decrease in tube voltage from 120 kVp to 100 kVp on dose, contrast-to-noise ratio (CNR), and three-dimensional (3D) image quality in patients undergoing computed tomographic (CT) colonography as well as to determine how these changes are affected by patient size. MATERIALS AND METHODS: This HIPAA-compliant and institutional review board-approved retrospective study included 63 consecutive patients who underwent CT colonography and who waived informed consent. Scanning was performed with patients in the supine (120 kVp) and prone (100 kVp) positions, with other parameters unchanged. Volume CT dose index (CTDI(vol)), dose-length product (DLP), image noise, attenuation of selected materials, and CNR were compared with the Wilcoxon matched-pairs signed rank test. Two readers blinded to tube voltage independently assessed 3D endoluminal image quality. The k coefficients were calculated for interobserver agreement. Average image quality ratings were compared with the Wilcoxon signed rank test. All recorded data were stratified by patient anteroposterior diameter to determine effects of patient size. RESULTS: Decreasing tube voltage from 120 to 100 kVp resulted in a 20% decrease in CTDI(vol) (P < .001) and a 16% decrease in DLP (P < .001). Image noise increased by 32% (P < .001). Mean attenuation of tagged fluid increased from 395 to 487 HU (P < .001). There was no change in mean CNR of tagged fluid (17.1 at 120 kVp, 16.8 at 100 kVp; P = .37), regardless of patient size. The 3D image quality decreased slightly from a median score of 5 out of 5 to 4 out of 5 (P < .001). There was substantial interobserver agreement. CONCLUSION: A decrease in tube voltage from 120 to 100 kVp results in a significant decrease in radiation dose but only a minimal decrease in 3D image quality at all patient sizes. © RSNA, 2012.

Utility of MRI after inconclusive ultrasound in pediatric patients with suspected appendicitis: retrospective review of 60 consecutive patients.

OBJECTIVE: The purpose of this study is to examine the utility of appendix MRI in evaluation of pediatric patients with right lower quadrant pain and inconclusive appendix sonography findings. MATERIALS AND METHODS: A search of the radiology electronic database was performed for all appendix MRI examinations performed of pediatric patients within 24 hours after inconclusive appendix sonography from December 1, 2009, through April 26, 2012. Sixty patients underwent appendix MRI within 24 hours of inconclusive sonography and represented the study cohort. MRI examinations were reviewed independently by two radiologists blinded to the diagnosis and were graded as "positive," "negative," or "indeterminate" for acute appendicitis. The final diagnosis was established by review of the surgical and pathology reports and patients' electronic medical records. RESULTS: Ten of 60 patients (17%) had acute appendicitis. Both readers graded the same 12 examinations as positive and the same 48 examinations as negative for acute appendicitis, with a kappa value of 1.00 (expected agreement, 0.695). No MRI examination was interpreted as indeterminate. The sensitivity and specificity of MRI for acute appendicitis in children with inconclusive appendix ultrasound findings were 100% (95% CI, 0.72-1.00) and 96% (95% CI, 0.87-0.98), respectively. The positive predictive value for the examination was 83%, the negative predictive value was 100%, and overall test accuracy was 97%. CONCLUSION: Our study shows that MRI has a sensitivity of 100% and specificity of 96% for appendicitis in pediatric patients after inconclusive appendix sonography. We think that MRI may supplant CT as the secondary modality to follow inconclusive appendix sonography.

Effect of patient size on mean sterile water attenuation during multiphase CT examinations.

OBJECTIVE: The purpose of this study was to determine the variability of attenuation measurements in a water phantom included in the FOV during multiphase 64-MDCT. SUBJECTS AND METHODS: Ninety-seven consecutively registered patients undergoing multiphase kidney and liver protocol CT of the abdomen on the same 64-MDCT scanner had a sealed water bottle placed on their anterior abdomen during the examination. Region of interest (ROI) measurements of the mean attenuation (in HU) of the water bottle were made during the unenhanced, dynamic, and delayed phases of contrast enhancement. Generalized estimating equations were used to model mean attenuation in the ROI as a function of cross-sectional patient area, contrast phase, and protocol. Day of month and time of day were covariates. A phantom was created to model the patient study. RESULTS: The mean attenuation values in the water bottle ROIs were -13.1 HU for the kidney protocol and -9.1 HU for the liver protocol in the unenhanced phase, -11.7 HU for the kidney and -9.5 HU for the liver protocol in the dynamic phase, and -11.9 HU for the kidney and 11.0 HU for the liver protocol in the delayed phase. Kidney protocol water bottle ROI attenuation values were lower than the liver values (p = 0.04). In all phases with both protocols, the values differed from 0 HU (all p < 0.0001). Water bottle ROI attenuation decreased as patient cross-sectional area increased (-0.01 HU/cm(2), p < 0.0001). Three patients had absolute water bottle attenuation changes greater than 20 HU between phases. Day of the month (p = 0.08) and time of day (p = 0.93) were not significant factors. Phantom data supported the study findings. CONCLUSION: The mean attenuation of water decreased as patient diameter increased. Both artifactual enhancement and decrease in enhancement greater than 20 HU were found in three larger patients.

Morphologic features of 211 adrenal masses at initial contrast-enhanced CT: can we differentiate benign from malignant lesions using imaging features alone?

OBJECTIVE: The objective of our study was to determine whether morphologic features of adrenal masses detected at initial contrast-enhanced MDCT can differentiate benign from malignant disease. MATERIALS AND METHODS: Two hundred eleven adrenal masses (1-4 cm) detected during standard contrast-enhanced MDCT with a proven final diagnosis were retrospectively identified in 188 patients through a computer search of CT, PET/CT, and pathology reports. Three authors blinded to the diagnoses independently reviewed the contrast-enhanced MDCT images of the adrenal masses and evaluated their morphologic features: lesion margin (smooth, lobulated, or irregular), density (homogeneous or heterogeneous), and additional features of central low density and enhancing rim. Using these criteria, the readers categorized each mass as probably benign, indeterminate, or suspicious. RESULTS: There were 171 (81%) benign and 40 (19%) malignant adrenal masses. All malignant masses were metastases diagnosed in patients with known extraadrenal malignancy. For individual morphologic features in diagnosing malignancy, irregular margins had 30-33% sensitivity and 95-96% specificity and an enhancing rim had 5-13% sensitivity and 98-99% specificity. None of the imaging features was reliable in predicting benignity. When an adrenal mass was deemed suspicious by a reader, the sensitivities for malignancy ranged from 54% to 74% and specificities from 96% to 97%. Notably, no malignant lesions occurred in patients without a known history of cancer. CONCLUSION: At routine contrast-enhanced MDCT, adrenal masses with irregular margins or a thick enhancing rim are likely to be malignant. Smooth margins and homogeneous density can be seen in both benign and malignant adrenal masses and are insufficient for characterization.

Lexicon for adrenal terms at CT and MRI: a consensus of the Society of Abdominal Radiology adrenal neoplasm disease-focused panel.

PURPOSE: Substantial variation in imaging terms used to describe the adrenal gland and adrenal findings leads to ambiguity and uncertainty in radiology reports and subsequently their understanding by referring clinicians. The purpose of this study was to develop a standardized lexicon to describe adrenal imaging findings at CT and MRI. METHODS: Fourteen members of the Society of Abdominal Radiology adrenal neoplasm disease-focused panel (SAR-DFP) including one endocrine surgeon participated to develop an adrenal lexicon using a modified Delphi process to reach consensus. Five radiologists prepared a preliminary list of 35 imaging terms that was sent to the full group as an online survey (19 general imaging terms, 9 specific to CT, and 7 specific to MRI). In the first round, members voted on terms to be included and proposed definitions; subsequent two rounds were used to achieve consensus on definitions (defined as ≥ 80% agreement). RESULTS: Consensus for inclusion was reached on 33/35 terms with two terms excluded (anterior limb and normal adrenal size measurements). Greater than 80% consensus was reached on the definitions for 15 terms following the first round, with subsequent consensus achieved for the definitions of the remaining 18 terms following two additional rounds. No included term had remaining disagreement. CONCLUSION: Expert consensus produced a standardized lexicon for reporting adrenal findings at CT and MRI. The use of this consensus lexicon should improve radiology report clarity, standardize clinical and research terminology, and reduce uncertainty for referring providers when adrenal findings are present.

Placement of marker coils at biopsy: usefulness in the localization of poorly visualized renal neoplasms for subsequent CT-guided radiofrequency ablation.

PURPOSE: To determine whether placement of marking coils at biopsy of small renal neoplasms to facilitate localization at subsequent radiofrequency (RF) ablation is safe and can reduce fluoroscopy time during the ablative procedure. MATERIALS AND METHODS: This retrospective study was approved by the hospital institutional review board and was compliant with HIPAA. The requirement to obtain informed consent was waived. A search of the renal RF ablation database (235 patients) identified 23 consecutive patients who had a marking coil placed at biopsy of a renal neoplasm (coil group) and 23 patients who did not have a marking coil placed at biopsy (control group). The patients were matched for tumor characteristics, including size, parenchymal position, location in the kidney, and laterality. All patients underwent subsequent RF ablation. The authors compared computed tomographic (CT) fluoroscopy times and technical success rates between the two groups. Statistical analyses were performed by using a single-tailed paired t test for comparison of CT fluoroscopy times, a two-tailed paired t test for comparison of age and tumor size, and a single-tailed McNemar test for comparison of the technical success rate of ablation. RESULTS: The mean CT fluoroscopy time for the RF ablation procedure was 28 seconds ± 11.7 (standard deviation) for the coil group and 66 seconds ± 85.8 for the control group (P = .025). There was no significant difference in the technical success rates of renal RF ablation. CONCLUSION: For small renal neoplasms that are poorly visualized at unenhanced CT, placement of a metallic marking coil at biopsy facilitates tumor localization, thus reducing CT fluoroscopy time and radiation dose for subsequent RF ablation procedures.

Incidental clinically important extraurinary findings at MDCT urography for hematuria evaluation: prevalence in 1209 consecutive examinations.

OBJECTIVE: The purpose of this study is to describe the prevalence and the characteristics of clinically important incidental extraurinary findings detected at MDCT urography performed for hematuria. MATERIALS AND METHODS: A computer search of CT reports using the term "hematuria" identified 1209 reports of patients who had undergone MDCT urography. The results were retrospectively reviewed to determine unsuspected extraurinary findings that are clinically important or potentially important, warranting further imaging studies or medical or surgical intervention. We further categorized these important findings as acute (i.e., requiring immediate medical attention) or nonacute (i.e., requiring further evaluation in a nonurgent manner). By use of our electronic medical records, these findings were correlated to histologic diagnosis, further imaging evaluation, and clinical information. RESULTS: In 82 of 1209 patients (6.8%), 85 clinically important incidental extraurinary findings were identified. Follow-up evaluation was available for 43 of 85 (50.6%) findings by histologic diagnosis (n = 9), imaging evaluation (n = 31), or clinical information (n = 3). There were 11 (0.9%) examinations with acute findings, of which acute inflammation of the gastrointestinal tract and pancreaticobiliary system were the most common. Seventy-two (5.9%) examinations revealed 74 nonacute but important findings. Lung nodules were the most prevalent, followed by intraabdominal aneurysms and cystic ovarian masses. There were five (0.4%) histologically proven malignant neoplasms. CONCLUSION: The prevalence of clinically important incidental extraurinary findings at MDCT urography performed for hematuria was 6.8%.

Inadvertent ingestion of wire bristles from a grill cleaning brush: radiologic detection of unsuspected foreign bodies.

OBJECTIVE: We report acute onset of either odynophagia or abdominal pain immediately after ingestion of grilled meat in six patients presenting between May 1, 2009, and November 18, 2010. In all six patients, radiologic studies revealed a linear metallic foreign body. Careful history revealed cleaning of the grill with a metallic brush immediately before cooking in all six cases. CONCLUSION: Physicians should be aware of this potential hazard to facilitate accurate and timely diagnosis.

Solid renal masses: effectiveness and safety of image-guided percutaneous radiofrequency ablation.

With increasing emphasis on minimally invasive nephron-sparing techniques for treatment of renal tumors, image-guided percutaneous radiofrequency ablation (RFA) has emerged as a safe and effective method of tumor eradication that may be performed on an outpatient basis, with relatively low morbidity and mortality. This review addresses the clinical and technical considerations, risks, complications, and currently reported efficacy data pertaining to RFA of renal tumors, as well as the standardized approach to treatment and follow-up currently used in our practice.