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Background: Chilaiditi's sign is an incidental radiographic finding, associated with intestinal disposition located between liver and right diaphragm. It is considered as an acquired rather than a congenital condition and the prevalence ranges from 1.18% to 2.4% according to recent adult retrospective studies. The aspects of this rare entity with regards to a 7-month-old male initially misdiagnosed as diaphragmatic hernia is discussed., Case Presentation: A 4-month-old Caucasian male was misdiagnosed with a congenital diaphragmatic hernia owing to previous hospitalization with complaints of respiratory tract infection. On admission 3 months later, he was free of any signs and symptoms of intestinal obstruction or respiratory distress. Thorax computed tomography revealed Chilaiditi's sign. A diagnostic laparoscopy was regarded necessary to evaluate the anatomical details. The most prominent finding was the lack of muscle fibers and almost transparent appearance of the medial aspect of the partially eventrated right hemidiaphragm. Owing to delicate anatomical presentation, diaphragmatic plication was considered hazardous. The patient is doing well and under follow-up., Conclusions: It is obvious that Chilaiditi's sign is not always a completely incidental finding of no consequence, and may indicate an underlying congenital diaphragmatic pathology, clearly defined by laparoscopic evaluation in this case., (© 2024. The Author(s).)

This study investigated recurrence rates and treatment efficacy based on tomographic findings during a long-term follow-up after primary spontaneous pneumothorax (PSP) treatment. We retrospectively analyzed patients with PSP treated at our hospital between 2003 and 2020. Patients were categorized into 2 groups based on computed tomography (CT) findings: group 1 (no bulla/bleb) and group 2 (bullae-bleb <3 cm). Data on demographics, recurrence, treatment methods, and outcomes were also collected and compared. A total of 251 PSP cases were evaluated, predominantly male (93.6%) with a mean age of 29.23 ± 1.14 years. Most cases (57%) occurred on the right side. Recurrence rates were highest within the first year (77.8%), with the first and second recurrences occurring at rates of 26% and 27.3%, respectively. In group 1 (n = 117), conservative treatment was applied in 15 cases, tube thoracostomy in 81, autologous blood pleurodesis (ABP) in 19, and surgery in 12. Recurrence rates were 46.6%, 21%, 5.3%, and 8.3%, respectively. In group 2 (n = 134), the recurrence rates were 50%, 32.7%, 20%, and 3.1%, respectively (P < .001). No mortality was observed for any patient. The treatment groups included conservative (n = 19), thoracostomy (n = 179), ABP (n = 34), and surgical (n = 44) groups. Recurrence rates were 47.3%, 27.4%, 11.8% (group 1: 5.3%, group 2: 20%, P = .035), and 4.5% (0% vs 6.3%), respectively. ABP effectively reduced recurrence in group 1 PSP patients without bullae or blebs on CT, potentially avoiding surgery. Video-assisted thoracoscopic surgery should be preferred in group 2 cases with bullae or blebs to minimize recurrence. These results underscore the importance of tailoring treatment strategies based on CT findings to optimize PSP management outcomes., Competing Interests: The authors have no conflicts of interest to disclose., (Copyright © 2024 the Author(s). Published by Wolters Kluwer Health, Inc.)

To identify the radiological parameters which may help to predict the success of ureteral access sheath (UAS) placement during retrograde intrarenal surgery (RIRS).The study included 49 patients in whom failure ureteral access sheath placement in RIRS and 49 control group patients who were successfully placement between January 2023 and December 2023. The age, gender, body mass index (BMI), non-contrast computed tomography (NCCT), and kidney ureter bladder (KUB) radiographs were compared between the two groups. Measurements of the anteroposterior (ap) diameter of the pelvic inlet, anteroposterior diameter of the pelvic outlet, interspinous distance diameter were taken from non-contrast computed tomography (NCCT), while pelvic anteroposterior diameter and pelvic lateral diameter were measured from kidney ureter bladder (KUB) radiography. There were no significant differences between the groups in age, gender, body mass index, ap pelvic inlet diameter, ap pelvic outlet, and interspinous distance diameter. However, a statistically significant difference was found between the pelvic ap diameter and pelvic lateral diameter values measured on the KUB radiography. The values for pelvic ap diameter and pelvic lateral diameter measured in the KUB radiographs can be used to predict the likelihood of UAS passage during RIRC procedures. However, further studies with larger patient groups are needed to establish a cut-off value., (© 2024. The Author(s).)

Purpose: To evaluate the role of certain radiological parameters and patient characteristics in predicting the success of endoscopic treatment in ureteral stricture disease., Methods: Fifty one adult patients with ureteral stricture disease (< 1 cm) after developing due to upper ureteral stones with ureteroscopic laser disintegration were included and in addition to stone and patient parameters, radiological parameters including ureteral wall thickness (UWT) at the impacted stone site were also measured on computed tomography (CT) images. Patients were divided into two groups: Group 1: Patients with endoscopic treatment success and Group 2: Patients with endoscopic treatment failure. The possible relationship between the UWT values and other radiological parameter was comparatively evaluated., Results: Mean UWT value assessed at the treated stone site was significantly higher in cases unresponsive to endoscopic treatment with values of 2.77 ± 1.03 mm and 4.25 ± 1.32 mm in Group 1 and 2 respectively. A cut off value 3.55 mm for UWT was found to be highly predictive for endoscopic treatment failure., Conclusions: Our current results indicated that assessment of UWT value at the obstructing stone could be helpful enough to predict the likelihood of failure following endoscopic management of strictures with high sensitivity and specificity. Evaluation of this particular parameter could let the endourologists to look for more rational treatment alternatives with necessary measures taken on time., (© 2024. The Author(s).)

Aim: To provide a comprehensive analysis for accurate screw size selection and insertion angle during surgical procedures., Material and Methods: In this retrospective study, a total of 120 patients participated, resulting in the analysis of 240 occipital condyles using coronal, sagittal, and axial planes on CT scans. Statistical evaluation was performed using the Wilcoxon rank-sum test, with p < 0.05 considered statistically significant., Results: The mean sagittal length and height were measured at 17.2 ± 1.7 mm and 9.1 ± 1.5 mm, respectively. The average condyle angle, a crucial factor for screw insertion, was assessed at 38.0 ± 5.5 mm in length, 19.6 ± 2.6 mm in width, and 9.5 ± 1.0 mm in height. Condyle height in the anterior and posterior hypoglossal canals was measured at 10.8 ± 1.4 mm and 9.0 ± 1.4 mm, respectively. Screw angle and condyle width were statistically smaller in females compared to the male population., Conclusion: The OC is a significant anatomical structure in the craniovertebral junction, playing a crucial role in stability. The obtained morphological values are applicable to the Turkish population and offer statistically significant findings for preoperative planning involving occipital condyle screw instrumentation.

Purpose: Computational dosimetry software is routinely used to evaluate the organ and effective doses from computed tomography (CT) examinations. Studies have shown a significant variation in dose estimates between software in adult cohorts, and few studies have evaluated software for pediatric dose estimates. This study aims to compare the primary organ and effective doses estimated by four commercially available CT dosimetry software to thermoluminescent dosimeter (TLD) measurements in a 1-year-old phantom., Methods: One hundred fifteen calibrated LiF (Mg, Cu, P)-TLD 100-H chips were embedded within an anthropomorphic phantom representing a 1-year-old child at positions that matched the approximate location of organs within an infant. The phantom was scanned under three protocols, each with whole-body coverage. The mean absorbed doses from 25 radiosensitive organs and skeletal tissues were determined from the TLD readings. Effective doses for each of the protocols were subsequently calculated using ICRP 103 formalism. Dose estimates by the four Monte Carlo-based dose calculation systems were determined and compared to the directly measured doses., Results: Most organ doses determined by computation dosimetry software aligned to phantom measurements within 20%. Additionally, comparisons between effective doses are calculated using computational and direct measurement methods aligned within 20% across the three protocols. Significant variances were found in bone surface dose estimations among dosimetry methods, likely caused by differences in bone tissue modeling., Conclusion: All four-dosimetry software evaluated in this study provide adequate primary organ and effective dose estimations. Users should be aware, however, of the possible estimated uncertainty associated with each of the programs., (© 2022 The Authors. Journal of Applied Clinical Medical Physics published by Wiley Periodicals, LLC on behalf of The American Association of Physicists in Medicine.)

Background: In patients with hydrocephalus who undergo ventriculoperitoneal shunt placement, the ventricular catheter tip position is one of the most important prognostic factors influencing shunt survival. The aim of this study was to present our findings of ventriculoperitoneal shunt placement performed with intraoperative computed tomography (CT) and to evaluate the effect of intraoperative CT-based image guidance on optimal catheter positioning and overall shunt survival., Methods: Of the study enrolled 345 patients with hydrocephalus who underwent ventriculoperitoneal shunt placement for the first time between 2008 and 2018. Ventricular catheters were inserted freehand via the Kocher point into the lateral ventricle in all patients. In 163 patients, intraoperative CT was performed to confirm the tip position. In this group of patients, if the tip position was nonoptimal, the catheter was ejected and reinserted during the surgery. In the remaining 182 patients, the tip position was assessed with routine postoperative CT. The effect of performing intraoperative CT on catheter tip positioning and shunt failure was investigated., Results: Nonoptimal tip position was significantly correlated with shunt dysfunction even when excluding nonobstructive causes (P < 0.001). In the intraoperative CT group, 11 ventricular catheters (6.7%) were intraoperatively repositioned. The repositioning significantly improved the optimal tip position rate from 54% to 58.3% (P = 0.007). Intraoperative CT usage also showed direct correlation with shunt survival (P = 0.006)., Conclusions: Intraoperative CT is an effective tool for increasing the rate of optimal tip positioning and thereby overall shunt survival., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Background Percutaneous ablation for cT1 renal cell carcinoma (RCC) remains underused, partially because of heterogeneous and limited long-term outcomes data assessing recent cryoablation methods. Purpose To report intermediate- to long-term outcomes of image-guided percutaneous cryoablation of cT1 RCC and to compare outcomes for CT versus MRI guidance. Materials and Methods This HIPAA-compliant retrospective single-institution study assessed patients who underwent percutaneous cryoablation for solitary pathology-proven cT1 RCC between August 2000 and July 2017. Tumors (cT1a, n = 282; cT1b, n = 25; size range, 0.6-6.5 cm; median size, 2.5 cm) underwent cryoablation with CT ( n = 155) or MRI ( n = 152) guidance. Primary end points of overall survival (OS), disease-specific survival (DSS), imaging-confirmed disease-free survival (DFS), and local progression-free survival (LPFS) were calculated by using Kaplan-Meier analysis. Secondary end points of technique efficacy and adverse event rate were also calculated. Primary and secondary end points for CT and MRI guidance were compared by using univariable regression analysis. Results A total of 307 patients (mean age, 68 years ± 11 [standard deviation]; 192 men) were evaluated. Median clinical follow-up lasted 95 months (range, 8-219 months), and median imaging follow-up lasted 41 months (range, 0-189 months). Survival metrics at 3, 5, 10, and 15 years, respectively, included OS of 91% (95% confidence interval [CI]: 88%, 94%), 86% (95% CI: 82%, 90%), 78% (95% CI: 73%, 84%), and 76% (95% CI: 69%, 83%); DSS of 99.6% (95% CI: 99%, 100%), 99% (95% CI: 98%, 100%), 99% (95% CI: 98%, 100%), and 99% (95% CI: 98%, 100%); DFS of 94% (95% CI: 92%, 97%), 91% (95% CI: 88%, 96%), 88% (95% CI: 83%, 93%), and 88% (95% CI: 83%, 93%); and LPFS of 97% (95% CI: 94%, 99%), 95% (95% CI: 93%, 98%), 95% (95% CI: 93%, 98%), and 95% (95% CI: 93%, 98%). Survival did not significantly differ between CT and MRI guidance, with univariable Cox regression analysis hazard ratios of 0.97 (95% CI: 0.57, 1.67; P = .92) for OS, 0.63 (95% CI: 0.26, 1.52; P = .30) for DFS, and 0.83 (95% CI: 0.26, 2.74; P = .77) for LPFS. Primary and secondary technique efficacy were 96% and 99%, respectively. Overall adverse event rate was 14% (43 of 307), including 11 grade 3 events and three grade 4 events according to the Common Terminology Criteria for Adverse Events. Conclusion Percutaneous CT- and MRI-guided cryoablation of cT1 renal cell carcinoma had similar excellent intermediate- and long-term outcomes. © RSNA, 2020 Online supplemental material is available for this article. See also the editorial by Georgiades in this issue.

Introduction: To assess the performance of pre-ablation computed tomography texture features of adrenal metastases to predict post-treatment local progression and survival in patients who underwent ablation using machine learning as a prediction tool., Materials and Methods: This is a pilot retrospective study of patients with adrenal metastases undergoing ablation. Clinical variables were collected. Thirty-two texture features were extracted from manually segmented adrenal tumors. A univariate cox proportional hazard model was used for prediction of local progression and survival. A linear support vector machine (SVM) learning technique was applied to the texture features and clinical variables, with leave-one-out cross-validation. Receiver operating characteristic analysis and the area under the curve (AUC) were used to assess performance between using clinical variables only versus clinical variables and texture features., Results: Twenty-one patients (61% male, age 64.1 ± 10.3 years) were included. Mean time to local progression was 29.8 months. Five texture features exhibited association with progression (p < 0.05). The SVM model based on clinical variables alone resulted in an AUC of 0.52, whereas the SVM model that included texture features resulted in an AUC 0.93 (p = 0.01). Mean overall survival was 35 months. Fourteen texture features were associated with survival in the univariate model (p < 0.05). While the trained SVM model based on clinical variables resulted in an AUC of 0.68, the SVM model that included texture features resulted in an AUC of 0.93 (p = 0.024)., Discussion: Pre-ablation texture analysis and machine learning improve local tumor progression and survival prediction in patients with adrenal metastases who undergo ablation.

Purpose: The main objective of the study was to examine the morphometric development of the facial canal in temporal bones aged from one to 18 years for pediatric otosurgeons and neurosurgeons., Methods: The study was performed on 41 patients including cochlear implantation cases (20 females and 21 males) with a mean age of 6.44 ± 5.79 years. All the measurements belonging to the facial canal including the length, width and angles of its segments were performed using the data of computed tomography assessment., Results: The numerical data of the facial canal segments were not different in terms of sexes or sides, statistically (p > 0.05). The width of the labyrinthine segment (p = 0.145), the length of the tympanic segment (p = 0.555), the first (p = 0.067) and second (p = 0.060) genu angles seemed to reach adult size at two years of age. In addition, the length of the labyrinthine segment (p = 0.064) and the width of the mastoid segment (p = 0.264) seemed to attain adult size at four years, while the width of the meatal foramen (p = 0.264) seemed to arrive adult size at seven years. However, the length of the mastoid segment and the width of the tympanic segment were developing independently of increasing age between 1 and 18 years., Conclusion: Our data suggested that, contrary to the general acceptance in the literature, the dimension of the facial canal segments show remarkable changes during the transition from intrauterine life to adult life. The regression equations representing the facial canal growth dynamic in children may be useful for otosurgeons to estimate the size of its segments and to prevent iatrogenic injury during early childhood surgeries such as cochlear implantation., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Background: Aneurysmal bone cyst (ABC) is a benign bone tumor. Curettage and bone grafting is the common treatment. Here, we retrospectively evaluate nine patients treated with denosumab., Procedure: Nine patients with ABC, mostly pelvic and vertebral, treated with denosumab were analyzed retrospectively. A 70 mg/m 2 denosumab dose was used weekly in the first month, and then monthly. Clinical and radiological responses to treatment were evaluated., Results: In all patients, clinical symptoms including pain and limping regressed completely within 3 months. Radiological evaluation revealed changes in lesion size and content. In six patients, overall volume reduction in the range of 18-82% was detected. Decreases in the size and number of cysts were detected in eight patients. In five patients, fat signal appeared on follow-up imaging. No major side effects were observed during treatment. Median follow-up time after treatment was 15 months. At 5 months, severe hypercalcemia was observed in two patients due to rebound increase in osteoclastic activity. Subsequent to denosumab treatment, three patients underwent surgery for clinical or radiological recurrence., Conclusions: Our results showed that denosumab provided a meaningful clinical and radiological improvement in ABC. It may be a treatment option, especially in spinal and pelvic tumors with potentially high surgical morbidity. However, late rebound hypercalcemia may restrict its use. Studies with more cases are required for routine use of denosumab in ABC., (© 2017 Wiley Periodicals, Inc.)

Objective: Limited data exist on the incidence of contrast induced nephropathy (CIN) and its impact on in-hospital prognosis of patients diagnosed with acute pulmonary embolism (APE) using contrast computerized tomography pulmonary angiography (CTPA). In this study, we examined the frequency of nephropathy after CTPA in APE patients and its link to in-hospital adverse outcomes., Methods: This was a retrospective study of 189 patients (mean age 67+16years, 48% male) with APE who underwent CTPA. CIN was defined as a≥0.5mg/dl and/or ≥25% increase in serum creatinine levels >48hours after CTPA. Patients were divided into two groups according to the presence or absence of CIN to compare clinical characteristics, risk factors, and in-hospital adverse events., Results: Twenty-four (13%) of the patients were diagnosed with CIN. Patients with CIN were older (73±17 vs. 67±15years, P=.01) and had higher rates of heart failure (17% vs. 6%, P=.04). Preexisting renal dysfunction and advanced age were found to be independent predictors of CIN (OR: 4.2, 95% CI: 1.5-11.9, P=.006; OR: 3.2, 95% CI: 1.1-9.8, P=.03 respectively). The in-hospital adverse event rate was significantly higher in patients with CIN (16.7% vs. 2.4%, P=.001). A multivariate analysis revealed CIN as an independent predictor of in-hospital adverse event rate (OR: 6.1, 95%CI: 1.2-29.3, P=.02)., Conclusion: CIN is associated with a higher in-hospital adverse event rate in APE patients diagnosed using CTPA. This is first large study to focus specifically on CIN in patients diagnosed with APE using CTPA., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Purpose: We aimed to evaluate the effectiveness of the brain region imaging in FDG-PET/CT scanning of patients with suspected or diagnosed lung cancer., Materials and Methods: We performed the study retrospectively on the medical charts of 427 patients. We divided the FDG-PET/CT field of view (FOV) into four major imaging regions: brain, head-neck, abdomen and pelvis. Metastatic findings on these regions were checked and determined the potential of these findings to affect the chemotherapy or radiotherapy protocol or surgical management. If metastatic findings had a potential to modify these parameters, we named this situation as "clinical contribution". Considering the number of bed positions of these regions, we calculated the clinical contribution of each region and named as "effective clinical contribution". Then, we calculated the metastatic findings, clinical contribution, and effective clinical contribution ratios., Results: We found different brain metastasis ratios for lung cancer, solitary pulmonary mass (SPM), and solitary pulmonary nodule (SPN) groups (8.7, 2.8 and 0.9 %, respectively). In addition, the clinical contribution and effective clinical contribution ratios in the brain region for these three groups were 6.4, 2.8, 0.0 and 6.4, 2.8, 0.0 %, respectively. The highest metastatic findings (30.6 %) and clinical contribution (9.8 %) ratios were found in the abdomen region of the lung cancer group. However, the highest effective clinical contribution ratio (6.8 %) was found in the brain region within the same group., Conclusions: The addition of the brain region to the limited whole-body FOV in FDG-PET/CT scanning seems to be effective in the lung cancer and SPM groups, but not in the SPN group.

Introduction: F-Fluorodeoxyglucose (F-FDG) PET/CT represents an imaging modality that is gaining increasingly more prominence in screening, staging, and therapeutic monitoring of malignant diseases. An incidental focus of uptake in different regions of the body is not an uncommon finding during PET/CT imaging. Patients with incidental gastrointestinal tract findings comprise ∼3% of the overall patient group. The aim of the current study was to provide contributory information in relation to the answer on the most appropriate approach in cases with incidental colonic F-FDG uptake., Patients and Methods: A retrospective examination was performed on PET/CT results of 5258 patients. Of these, 152 were recommended to undergo colonoscopy because of the presence of suspicious foci and 31 underwent colonoscopy within 60 days with biopsy from all visible lesions. These dates were also examined., Results: Of the 24 patients undergoing colonoscopy with a suspicion of malignancy, five (20.83%) had no pathological findings. Of the 19 (79.17%) cases with a pathological finding in endoscopy, histopathology showed a benign lesion in five (20.83%), premalignant lesion in seven (29.17%), and a malignant lesion in seven (29.17%). Among seven patients undergoing colonoscopy because of a suspicion of inflammatory bowel disease, five were free of pathological signs and two patients with pathological endoscopy findings had nonspecific inflammation as documented by histopathological examination., Conclusion: Colonoscopic and histopathological examination of the increased foci of colonic F-FDG uptake incidentally detected at PET/CT seems to be a plausible approach.

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). Multiple Wilcoxon Mann-Whitney (rank-sum) tests were used to compare dose-length product (DLP) between the two groups. Fisher's exact test was used to compare technique effectiveness at 12 months post ablation between the two groups., Results: Median DLP for the standard protocol group was 4833.5 mGy*cm (range, 1667-8267 mGy*cm); median DLP for the dose reduction group was 2648 mGy*cm (range, 850-7169 mGy*cm), significantly less than that of the standard protocol group (p<0.01). The technique effectiveness for the dose reduction group was not significantly different from that of the standard protocol group at 12 month follow up (p=0.434)., Conclusion: The radiation dose during percutaneous CT-guided cryoablation of renal tumors was substantial in both the standard and the dose reduction groups; however, it was significantly lower with the protocol change that reduced dose parameters and decreased the number of CT scans., (Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.)

Bilateral adrenalectomy is currently the only available treatment for adrenocorticotropic hormone (ACTH)-dependent Cushing's syndrome (ectopic ACTH syndrome) that is refractory to pharmacologic therapy. We describe two patients with refractory ectopic ACTH syndrome who were treated with CT-guided percutaneous microwave ablation of both hyperplastic adrenal glands in a single session: O ne was not a surgical candidate, and the other had undergone unsuccessful surgery. Following the procedure, both patients achieved substantial decreases in serum cortisol, symptomatic improvement, and decreased anti-hypertensive medication requirements.

Wegener's granulomatosis is a necrotising granulomatous vasculitis which has a variable manifestations in the chest that are best described on computed tomography. Imaging findings may include masses or nodules, which may cavitate; consolidations and ground-glass opacities. Wegener's granulomatosis can mimic pneumonia, malignancy, and noninfectious inflammatory diseases. The purpose of this pictorial essay is to demonstrate the characteristic computed tomography findings of pulmonary Wegener's granulomatosis.

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., Materials and Methods: Eight patients with 11 malignant central lung tumors (nine metastatic, two primary; mean, 2.6 cm; range, 1.0-4.5 cm) located adjacent to mediastinal or hilar structures were treated using CT-guided cryoablation in 10 procedures. Technical success and effectiveness rates were calculated, complications were tabulated and intraprocedural imaging features of ice balls were described., Results: All procedures were technically successful; imaging after 24 hours demonstrated no residual tumor. Five tumors recurred, three of which were re-ablated successfully. A hypodense ice ball with well-defined margin was visible during the first (n=6, 55%) or second (n=11, 100%) freeze, encompassing the entire tumor in all patients, and abutting (n=7) or minimally involving (n=4) adjacent mediastinal and hilar structures. Pneumothorax developed following six procedures (60%); percutaneous treatment was applied in three of them. All patients developed pleural effusions, with one patient requiring percutaneous drainage. Transient hemoptysis occurred after six procedures (60%), but all cases improved within a week. No injury occurred to mediastinal or hilar structures., Conclusion: CT-guided percutaneous cryoablation can be used to treat central lung tumors successfully. Although complications were common, they were self-limited, treatable, and not related to tumor location. Ice ball monitoring helped maximize the amount of tumor treated, while avoiding critical mediastinal and hilar structures.

A patient with a 2-year history of pain in the left arm, and decreased strengths unrelieved by non-steroidal anti-inflammatory therapy, was being referred for repeating radiography. The radiologic examinations have demonstrated a unique pattern of non-contiguous osteolysis in the left elbow, proximal and distal radius, ulna, wrist, carpal bones, proximal and distal metacarpals and phalanges. Multi-site biopsies were being performed and confirmed the diagnosis of massive osteolysis. To our knowledge, this is the first case in which multifocal, non-contiguous osteolysis with skip lesions without associated nephropathy and without a hereditary pattern is being described in one extremity.

Objective: The purpose of this study was to investigate myocardial findings of F-fluorodeoxyglucose PET/computed tomography (F-FDG PET/CT) after thoracic radiotherapy., Methods: F-Fluorodeoxyglucose PET/CT examination was performed in 38 patients at least 4 months after radiotherapy. Patients with known cardiac diseases, high cardiovascular risk factors, or diabetes mellitus were excluded., Results: On visual analysis, 28 patients were seen to have regional myocardial F-FDG uptake (74%), five patients were seen to have diffuse myocardial F-FDG uptake (13%), and five patients were seen to have no significant myocardial F-FDG uptake (13%). Regions of interest were drawn on irradiated and nonirradiated segments of the myocardium. The standardized uptake value measurements of the 28 patients with regional myocardial F-FDG uptake revealed significantly higher values in the irradiated segments in comparison with nonirradiated segments (P<0.001)., Conclusion: Annular or focal increased F-FDG uptake in irradiated myocardial segments may be observed after thoracic radiotherapy. These myocardial uptake regions were not consistent with the vascular territory of coronary arteries, and the patients had no prior myocardial infarction or coronary artery disease. The patients with a history of thoracic radiotherapy, who showed increased F-FDG uptake on PET/CT, especially in the basal myocardium, should be followed up cautiously for the early diagnosis of cardiac events.

The role of positron emission tomography/CT (PET/CT) in diagnosis and follow-up of newborns with hypoxic ischaemic encephalopathy has been documented before; however, this is the first presentation of elder children with both diagnostic and follow-up PET/CT results as far as we know.

Purpose: To estimate effective dose during CT-guided cryoablation of liver tumors, and to assess which procedural factors contribute most to dose., Materials and Methods: Our institutional review board approved this retrospective, HIPAA-compliant study. A total of 20 CT-guided percutaneous liver tumor cryoablation procedures were performed in 18 patients. Effective dose was determined by multiplying the dose length product for each CT scan obtained during the procedure by a conversion factor (0.015mSv/mGy-cm), and calculating the sum for each phase of the procedure: planning, targeting, monitoring, and post-ablation survey. Effective dose of each phase was compared using a repeated measures analysis. Using Spearman correlation coefficients, effective doses were correlated with procedural factors including number of scans, ratio of targeting distance to tumor size, anesthesia type, number of applicators, performance of ancillary procedures (hydrodissection and biopsy), and use of CT fluoroscopy., Results: Effective dose per procedure was 72±18mSv. The effective dose of targeting (37.5±12.5mSv) was the largest component compared to the effective dose of the planning phase (4.8±2.2mSv), the monitoring phase (25.5±6.8mSv), and the post-ablation survey (4.1±1.9mSv) phase (p<0.05). Effective dose correlated positively only with the number of scans (p<0.01)., Conclusions: The effective dose of CT-guided percutaneous cryoablation of liver tumors can be substantial. Reducing the number of scans during the procedure is likely to have the greatest effect on lowering dose., (Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.)

Haemophagocytic lymphohistiocytosis (HLH) is a rare immune disorder that predominantly affects macrophages and T lymphocytes and leads to multiple organ disease and death. The characteristic pathological finding in the bone marrow and the other affected tissues is haemophagocytosis of macrophages (macrophages digesting erythrocyte). Primary (hereditary) and secondary (acquired) forms of the disease are present. A patient with documented HLH disease revealed by positron emission tomography/CT is reported in this paper.

Positron emission tomography/CT examination was performed to 62-year-old male patient with diagnosis of Hodgkin lymphoma for treatment response which revealed complete response. During re-evaluation process of this patient in our department, asymmetrical brain metabolism defect of right thalamus and hipometabolism of right parietal lobe was observed. This finding was confirmed with additional CT imaging as a subacute infarct tissue.

Purpose: To develop a technique for guiding percutaneous biopsies of abdominal masses in a positron emission tomography (PET)/computed tomography (CT) scanner, and test its feasibility and safety in patients., Materials and Methods: The authors conducted a prospective study in 12 patients who were in need of both a diagnostic (18)F-fluoro-deoxy-D-glucose (FDG) PET/CT scan and a percutaneous biopsy of an abdominal mass, located in the liver (n = 7), presacral soft tissue (n = 2), lymph node (n = 2), and kidney (n = 1). After completion of the PET/CT scan, with the patient remaining on the table, a one-table-position PET/CT scan was obtained with a radiopaque grid in place, and the biopsy procedure was planned. Then, a biopsy needle was placed into the mass using one-table-position CT scan registered to the planning PET scan. Masses were sampled after confirming accurate positioning of the needle tips with a final one-table-position PET/CT scan. Negative results were confirmed independently with follow-up imaging., Results: All biopsy procedures yielded diagnostic results; nine were positive for malignancy, and three were negative (fibrosis, steatosis, and Escherichia coli infection). One non-FDG-avid mass biopsy yielded a malignant result. Seven masses were either invisible or poorly depicted with unenhanced CT scan, and two masses contained FDG avidity in only a portion of the mass. There were no complications., Conclusions: Although our data are preliminary, this initial experience suggests that abdominal masses can undergo successful biopsy in a PET/CT scanner. PET/CT guidance may be helpful when performing biopsy on FDG-avid masses that are either not visible with unenhanced CT or are FDG avid in only a portion., (Copyright © 2011 SIR. Published by Elsevier Inc. All rights reserved.)

Purpose: To determine if tumor fluorine-18 fluorodeoxyglucose ((18)F-FDG) activity is dissipated by radiofrequency (RF) ablation or cryoablation during tumor ablation guided by positron emission tomography/computed tomography (PET/CT)., Materials and Methods: This prospective study enrolled 12 patients (9 women and 3 men, 39-65 years old), each with at least one (18)F-FDG-avid liver, perihepatic, or lung tumor. Six patients (experimental group) underwent percutaneous PET/CT-guided RF ablation (n = 3) or cryoablation (n = 3). Six patients (control group) underwent diagnostic PET/CT-guided percutaneous biopsy. At a mean time of 103.5 minutes after a single intravenous (18)F-FDG dose, preprocedure and postprocedure PET/CT scans, separated by a mean time interval of 83.4 minutes, were obtained in all patients. Target tumor maximum standardized uptake value (TSUVmax) and ratio (SUVratio) of TSUVmax to normal liver average standardized uptake value (LSUVavg) were measured on all scans. Percentage changes in TSUVmax and SUVratio from preprocedure to postprocedure scans were compared for both groups and analyzed using the Student t test (P < .05 considered statistically significant)., Results: For all patients in both groups, TSUVmax and SUVratio increased from preprocedure to postprocedure PET/CT scans without statistically significant differences. The mean percentage increase in TSUVmax for the ablation group was 32.5% (range 8.2%-46.7%) and for the biopsy group was 24.6% (3.7%-42.4%; P = .45). The mean percentage increase in SUVratio for the ablation group was 47.9% (18.8%-69.6%) and for the biopsy group was 37.6% (9.4%-65%; P = .37)., Conclusions: Tumor (18)F-FDG activity is not dissipated by percutaneous RF ablation or cryoablation. When performing (18)F-FDG PET/CT-guided RF ablation or cryoablation, changes in target tumor (18)F-FDG activity cannot be used to monitor treatment effects., (Copyright © 2011 SIR. Published by Elsevier Inc. All rights reserved.)

Purpose: To determine whether a non-rigid registration (NRR) technique was more accurate than a rigid registration (RR) technique when fusing pre-procedural contrast-enhanced MR images to unenhanced CT images during CT-guided percutaneous cryoablation of renal tumors., Methods: Both RR and NRR were applied retrospectively to 11 CT-guided percutaneous cryoablation procedures performed to treat renal tumors (mean diameter; 23 mm). Pre-procedural contrast-enhanced MR images of the upper abdomen were registered to unenhanced intra-procedural CT images obtained just prior to the ablation. RRs were performed manually, and NRRs were performed using an intensity-based approach with affine and Basis-Spline techniques used for modeling displacement. Registration accuracy for each technique was assessed using the 95% Hausdorff distance (HD), Fiducial Registration Error (FRE) and the Dice Similarity Coefficient (DSC). Statistical differences were analyzed using a two-sided Student's t-test. Time for each registration technique was recorded., Results: Mean 95% HD (1.7 mm), FRE (1.7 mm) and DSC (0.96) using the NRR technique were significantly better than mean 95% HD (6.4 mm), FRE (5.0 mm) and DSC (0.88) using the RR technique (P < 0.05 for each analysis). Mean registration times of NRR and RR techniques were 15.2 and 5.7 min, respectively., Conclusions: The non-rigid registration technique was more accurate than the rigid registration technique when fusing pre-procedural MR images to intra-procedural unenhanced CT images. The non-rigid registration technique can be used to improve visualization of renal tumors during CT-guided cryoablation procedures.

Rationale and Objectives: The aim of this study was to develop non-rigid image registration between preprocedure contrast-enhanced magnetic resonance (MR) images and intraprocedure unenhanced computed tomographic (CT) images, to enhance tumor visualization and localization during CT imaging-guided liver tumor cryoablation procedures., Materials and Methods: A non-rigid registration technique was evaluated with different preprocessing steps and algorithm parameters and compared to a standard rigid registration approach. The Dice similarity coefficient, target registration error, 95th-percentile Hausdorff distance, and total registration time (minutes) were compared using a two-sided Student's t test. The entire registration method was then applied during five CT imaging-guided liver cryoablation cases with the intraprocedural CT data transmitted directly from the CT scanner, with both accuracy and registration time evaluated., Results: Selected optimal parameters for registration were a section thickness of 5 mm, cropping the field of view to 66% of its original size, manual segmentation of the liver, B-spline control grid of 5 × 5 × 5, and spatial sampling of 50,000 pixels. A mean 95th-percentile Hausdorff distance of 3.3 mm (a 2.5 times improvement compared to rigid registration, P < .05), a mean Dice similarity coefficient of 0.97 (a 13% increase), and a mean target registration error of 4.1 mm (a 2.7 times reduction) were measured. During the cryoablation procedure, registration between the preprocedure MR and the planning intraprocedure CT imaging took a mean time of 10.6 minutes, MR to targeting CT image took 4 minutes, and MR to monitoring CT imaging took 4.3 minutes. Mean registration accuracy was <3.4 mm., Conclusions: Non-rigid registration allowed improved visualization of the tumor during interventional planning, targeting, and evaluation of tumor coverage by the ice ball. Future work is focused on reducing segmentation time to make the method more clinically acceptable., (Copyright © 2010 AUR. Published by Elsevier Inc. All rights reserved.)

Purpose: To establish the feasibility of performing combined positron emission tomography (PET)/computed tomography (CT)-guided biopsy of abdominal masses by using previously acquired PET/CT images registered with intraprocedural CT images., Materials and Methods: In this HIPAA-compliant institutional review board-approved study, 14 patients underwent clinically indicated percutaneous biopsy of abdominal masses (mean size, 3.3 cm; range, 1.2-5.0 cm) in the liver (n = 6), presacral soft tissue (n = 3), retroperitoneal lymph nodes (n = 2), spleen (n = 2), and pancreas (n = 1). PET/CT images obtained no more than 62 days (mean, 18.3 days) before the biopsy procedure were registered with intraprocedural CT images by using image registration software. The registered images were used to plan the procedure and help target the masses., Results: The image registrations were technically successful in all but one patient, who had severe scoliosis. The remaining 13 biopsy procedures yielded diagnostic results, which were positive for malignancy in 10 cases and negative in three cases., Conclusion: PET/CT-guided abdominal biopsy with use of prior PET/CT images registered with intraprocedural CT scans is feasible and may be helpful when fluorine 18 fluorodeoxyglucose-avid masses that are not seen sufficiently with nonenhanced CT are sampled at biopsy.

Computed tomography (CT) and magnetic resonance imaging (MRI) reliably demonstrate typical features of schwannomas or neurofibromas in the vast majority of dumbbell lesions responsible for neural foraminal widening. However, a large variety of unusual lesions which are causes of neural foraminal widening can also be encountered in the spinal neural foramen. Radiologic findings can be helpful in differential diagnosis of lesions of spinal neural foramen including neoplastic lesions such as benign/malign peripheral nerve sheath tumors (PNSTs), solitary bone plasmacytoma (SBP), chondroid chordoma, superior sulcus tumor, metastasis and non-neoplastic lesions such as infectious process (tuberculosis, hydatid cyst), aneurysmal bone cyst (ABC), synovial cyst, traumatic pseudomeningocele, arachnoid cyst, vertebral artery tortuosity. In this article, we discuss CT and MRI findings of dumbbell lesions which are causes of neural foraminal widening.

CT guided tumor ablation of the liver often suffers from a lack of visualization of the target tumor and surrounding critical structures. This information is available on pre-operative contrast enhanced MR images and a non-rigid registration technique is desirable. However while registration methods have been successfully tested retrospectively on patient data, very few have been incorporated into clinical procedures. A non-rigid registration technique has been evaluated, optimized and validated to be able to perform registration of the liver between MR to CT images, and between intra-operative CT images. The method requires pre-processing and segmentation of the liver, and presents an accuracy of approximately 2 mm. A clinical feasibility study has been conducted in 5 liver ablation cases. The method helps clinicians enhance interventional planning, confirm ablation probe location with respect to the tumor, and in the case of cryotherapy, evaluate tumor coverage by the ice ball.

Some renal masses have higher attenuation than the surrounding renal parenchyma at computed tomography (CT). Their hyperattenuation is usually the result of proteinaceous fluid or densely packed cells. Most hyperattenuating renal masses are benign hemorrhagic or proteinaceous cysts. However, solid enhancing hyperattenuating renal masses may have malignant as well as benign causes. Possible malignant causes include renal cell carcinoma and lymphoma; benign causes include angiomyolipoma with minimal fat. It is important to identify the cause of a hyperattenuating renal mass so as to avoid unnecessary surgical resection or ablation. CT may be useful for diagnosing benign hyperattenuating renal cysts, hematomas, and vascular anomalies that appear masslike. However, some solid, enhancing, hyperattenuating masses cannot be diagnosed confidently with CT alone: Small (< or = 3-cm-diameter), homogeneously enhancing, hyperattenuating renal masses depicted on CT images may be either benign angiomyolipomas with minimal fat or renal cell carcinomas. Magnetic resonance (MR) imaging may be helpful for differentiating between angiomyolipomas with minimal fat and clear cell renal cell carcinomas; however, differentiation between angiomyolipomas with minimal fat and papillary renal cell carcinomas often is not possible on the basis of MR imaging. In such cases, a percutaneous biopsy may be useful for diagnosis. If the results of MR imaging and percutaneous biopsy are not definitive, surgery is warranted., (RSNA, 2007)

Objective: Imaging-guided biopsies of solid pancreatic masses are performed with either CT or endoscopic sonography at our institution. We compared test characteristics of fine-needle aspiration biopsies guided using CT with those guided using endoscopic sonography and secondarily evaluated for an effect of mass size., Materials and Methods: Of 70 solid pancreatic masses, 43 (mean size, 4.4 cm; range, 1.5-10.3 cm) underwent fine-needle (20- to 22-gauge) aspiration biopsy with CT guidance and 27 (mean size, 2.3 cm; range, 1.0-5.0 cm) underwent fine-needle (22-gauge) aspiration biopsy with endoscopic sonography guidance. The diagnostic rate, sensitivity, and negative predictive value (NPV) for each technique were compared using Fisher's exact test before and after stratifying masses by size as small (< or = 3 cm) or large (> 3 cm)., Results: The overall diagnostic rate, sensitivity, and NPV of fine-needle aspiration biopsies guided using CT (97.7%, 94.9%, and 60%, respectively) were not significantly different from those guided using endoscopic sonography (88.9%, 85%, and 57.1%, respectively). Among small masses, the diagnostic rate and sensitivity for biopsies guided using CT (100% and 100%, respectively) were not significantly different from those for biopsies guided using endoscopic sonography (90.9% and 93.8%, respectively). Among large masses, the diagnostic rate and sensitivity (96.6% and 92.3%, respectively) for biopsies guided using CT were not significantly different from those for biopsies guided using endoscopic sonography (83.3% and 50%, respectively)., Conclusion: When biopsying solid pancreatic masses with fine needles, procedures guided with CT and those guided with endoscopic sonography have similar test characteristics regardless of mass size.

This HIPAA-compliant pilot study had internal review board approval; informed consent was waived. The purpose was to determine retrospectively the diagnostic performance of a computer-aided three-dimensional (3D) analytic tool for assessing local recurrences of liver metastases by quantifying shape changes in ablated tumors on computed tomographic (CT) scans for follow-up of radiofrequency (RF) ablation. Positron emission tomographic and long-term CT follow-up images were reference standards. Fifty-six follow-up CT scans of 12 liver metastases (mean size, 4.0 cm) in nine patients treated with RF ablation were retrospectively analyzed. After the 1st month following RF ablation, the 3D analytic tool helped quantify ablated tumor shape variations and revealed recurrences even in the absence of abnormal enhancement (sensitivity, seven of seven; specificity, three of five). The 3D tool would have revealed a recurrence before it was reported clinically in two patients. Although results are preliminary, a 3D analytic tool based on shape may be useful in assessing RF ablation results., ((c) RSNA, 2006.)

Purpose: To retrospectively evaluate whether intravenous furosemide, either alone or in addition to intravenous saline, improved depiction of the normal urinary collecting system at multi-detector row computed tomographic (CT) urography., Materials and Methods: Institutional review board approval for review of patient images and medical records was obtained; informed consent was not required for this HIPAA-compliant study. Excretory phase images from multi-detector row CT urography in 87 patients (44 women, 43 men; age range, 21-83 years; mean, 53 years) were reviewed. Examinations were performed with, in addition to intravenous contrast medium, 250 mL of intravenous normal saline alone (n = 35), both 250 mL of normal saline and 10 mg of intravenous furosemide (n = 26), or 10 mg of furosemide alone (n = 26). Three readers, blinded to the imaging technique used, individually assigned opacification scores to each of six urinary collecting system segments. Urinary distention was assessed by one reader by measuring transverse widths of the proximal, middle, and distal ureteral segments. Mean opacification scores for each segment and mean ureteral width measurements for each technique were compared by using the Student t test., Results: Mean opacification scores achieved with furosemide were significantly higher than those achieved with saline for the middle (P

Objective: To assess the relation between mastoid size and attic blockage in COME patients treated with ventilation tube insertion and prognosis regarding tympanometric compliance and computed tomography findings of temporal bones., Material and Methods: Twenty-four ears of 15 patients with chronic otitis media with effusion were selected prospectively. The ages of patients were between 5 and 13 years old and eight of them were females. All patient received medical treatment for 10 days. Ventilation tubes were inserted with or without adenoidectomy or adenotonsillectomy to the unimproved patients. Postoperative compliances were measured on first day, first week, and first month and the tympanometric results were compared each one with others and with mastoid pneumatization degree using computerized tomographic findings., Results: The hearing thresholds were between 23 and 43 dB in left ears and between 22 and 45 dB in right ears. Mastoid pneumatization and aditus were normal and open in three (12.6%); sclerotic and open in eight (33.3%); sclerotic and blocked in 13 patients (54.1%), when the temporal bones assessed by computerized tomography. The mean compliance values of patients elevated postoperatively in regard with time and this increase was significant. There was a significant statistical relation between mastoid pneumatization and compliance of the ears., Conclusion: Tympanometric assessment may be considered as a valuable and cost-effective method rather than CT in the evaluation of aditus blockage and residual soft tissue of the tympanomastoid region.

Goals: We aimed to determine the role of thorax high-resolution computed tomography (HRCT) in demonstrating the pulmonary vasodilatation in patients with hepatopulmonary syndrome (HPS)., Background: Traditionally, the presence of intrapulmonary vascular dilatations can be detected by using one of the three diagnostic modalities: contrast-enhanced echocardiography, technetium 99 m-labeled macroaggregated albumin scan, and pulmonary angiography., Study: The study group included 10 patients with HPS (Group 1), 12 patients with normoxemic cirrhosis (Group 2), and 12 healthy controls (Group 3). All of the subjects underwent conventional and HRCT of thorax. The diameters of pulmonary trunk, main pulmonary arteries, and right lower lobe basal segmental arteries were measured. The ratios of right lower lobe basal segmental pulmonary artery to bronchus diameter were calculated., Results: The mean diameters of the main pulmonary trunk, right and left main pulmonary arteries were not different between the groups. Mean diameters of right lower lobe basal segmental pulmonary arteries were significantly higher in Group 1 compared with Group 2 (P=0.01) and Group 3 (P=0.002). Mean right lower lobe basal segmental pulmonary artery to bronchus ratios were significantly higher in Group 1 compared with Group 2 (P=0.03) and Group 3 (P<0.001). Group 2 had significantly higher pulmonary artery to bronchus ratios than Group 3 (P<0.001)., Conclusions: Thorax HRCT may be helpful in the diagnosis of HPS by demonstrating the dilated peripheral pulmonary vessels or increased pulmonary artery to bronchus ratios in patients with liver disease and hypoxemia.

Brachial plexus injury in a patient under general anesthesia (GA) is not uncommon, despite careful positioning and, particularly, awareness of the possibility. The mechanism of injury is stretching and compression of the brachial plexus over a prolonged period. Positioning the patient within the computed tomography (CT) gantry for abdominal or chest procedures can simulate a surgical procedure, particularly when GA is used. The potential for brachial plexus injury is increased if the case is prolonged and the patient's arms are raised above the head to avoid CT image degradation from streak artifacts. We report a case of profound brachial plexus palsy following a CT-guided radiofrequency ablation procedure under GA. Fortunately, the patient recovered completely. We emphasize the mechanism of injury and detail measures to combat this problem, such that radiologists are aware of this potentially serious complication.

Liver volume measurement has many clinical and research uses. The purpose of the present study is to evaluate experimentally the accuracy and reproducibility of spiral computed tomography (CT) in measuring liver volume. To determine the accuracy of spiral CT system, nine fresh (non-formalin-fixed) sheep livers were scanned in vitro. The collimation was 7 mm. The CT sections were stored on floppy disks and the images were transferred to the workstation that contained a software for volume measurement. The mean volume is 912+/-497 ml and the actual reference volume is 921+/-527 ml. The correlation between the CT system and actual reference measurement of sheep liver volumes was very strong. The correlation coefficient r was.998 (P<.001) on 7-mm sections. The mean difference between liver volume measurements was 4.95+/-3.23%. As a result, CT scan could be used as a reference noninvasive method for liver volume measurement in clinics.