Imaging evaluation of hereditary renal tumors: a pictorial review.

More than 10 hereditary renal tumor syndromes (HRTSs) and related germline mutations have been reported with HRTS-associated renal and extrarenal manifestations with benign and malignant tumors. Radiologists play an important role in detecting solitary or multiple renal masses with or without extrarenal findings on imaging and may raise the possibility of an inherited predisposition to renal cell carcinoma, providing direction for further screening, intervention and surveillance of the patients and their close family members before the development of potentially lethal renal and extrarenal tumors. Renal cell carcinomas (RCCs) associated with von Hippel-Lindau disease are typically slow growing while RCCs associated with HRTSs, such as hereditary leiomyomatosis and renal cell carcinoma syndrome, are highly aggressive. Therefore, radiologists need to be familiar with clinical and imaging findings of renal and extrarenal manifestations of HRTSs. This article reviews clinical and imaging findings for the evaluation of patients with well-established HRTSs from a radiologist's perspective to facilitate the clinical decision-making process for patient management.

Gradual enhancement pattern of tracheobronchial adenoid cystic carcinoma on multiphasic dynamic computed tomography†:†a case series.

Tracheobronchial adenoid cystic carcinoma is a rare malignancy. To the best of our knowledge, its enhancement pattern on multiphasic contrast-enhanced multidetector computed tomography has not been reported. Herein, we report the computed tomography findings of three consecutive cases of tracheobronchial adenoid cystic carcinoma. All lesions presented a gradual enhancement pattern on multiphasic contrast-enhanced computed tomography. We speculate that the gradual enhancement pattern on multiphasic contrast-enhanced computed tomography could potentially serve as a characteristic imaging feature and may therefore be a clue to diagnose tracheobronchial adenoid cystic carcinoma. J. Med. Invest. 67 : 378-381, August, 2020.

A Clinical Study Evaluating an Aspiration-type Semi-Automatic Cutting Biopsy Needle (SCIRO-1702).

An aspiration-type semi-automatic cutting biopsy needle enables tissue cutting during application of negative pressure, which is expected to contribute to a larger amount of specimen. The aim of the present study was to evaluate this novel needle in a clinical setting. Patients who underwent image-guided percutaneous biopsy for lung or renal masses were enrolled. Cutting biopsy was performed with and without aspiration during each procedure. The specimens were weighed using an electronic scale. The weights were compared between specimens obtained with and without aspiration using a paired t-test. The data from 45 lung and 30 renal biopsy procedures were analyzed. In lung biopsy, the mean±standard deviation weights of specimens obtained with and without aspiration were 2.20±1.05 mg and 2.24±1.08 mg, respectively. In renal biopsy, the mean weights were 6.52±2.18 mg and 6.42±1.62 mg, respectively. The weights were not significantly different between specimens obtained with and without aspiration either in lung (p=0.799) or renal (p=0.789) biopsies. The application of negative pressure with the aspiration-type semi-automatic cutting biopsy needle did not contribute to an increase in the amount of the specimen obtained in lung and renal biopsies.

The Diagnostic Capacity of Pre-treatment 18F-FDG PET/CT for Predicting the Extranodular Spread of Lymph Node Metastases in Patients with Oral Squamous Cell Carcinoma.

The aim of this study was to evaluate the ability of pretreatment 90-min 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) to predict the extranodular spread of lymph node metastases in oral squamous cell carcinoma. We retrospectively reviewed the cases of 56 patients who underwent pretreatment 18F-FDG PET/CT and surgery with neck dissection. Maximum standardized uptake value, metabolic tumor volume, and total lesion glycolysis were measured for the 56 primary sites and maximum standardized uptake value was measured for 115 lymph node levels. Extranodular spread was present at 9 lymph node levels in 7 patients. Significant differences were found in metabolic tumor volume and total lesion glycolysis of the primary site, and in lymph node maximum standardized uptake value, between patients with and without extranodular spread (p<0.05). Combining primary site total lesion glycolysis and lymph node maximum standardized uptake volume at their respective optimal cutoffs, the sensitivity, specificity, and accuracy for predicting extranodular spread were 89%, 92%, and 92%, respectively. Pretreatment 18F-FDG PET/CT is useful for predicting extranodular spread in patients with oral squamous cell carcinoma. The combined use of primary site total lesion glycolysis and lymph node maximum standardized uptake value showed greater predictive value than either predictor singly.

Differentiation of Small (≤ 4 cm) Renal Masses on Multiphase Contrast-Enhanced CT by Deep Learning.

OBJECTIVE. This study evaluated the utility of a deep learning method for determining whether a small (≤ 4 cm) solid renal mass was benign or malignant on multiphase contrast-enhanced CT. MATERIALS AND METHODS. This retrospective study included 1807 image sets from 168 pathologically diagnosed small (≤ 4 cm) solid renal masses with four CT phases (unenhanced, corticomedullary, nephrogenic, and excretory) in 159 patients between 2012 and 2016. Masses were classified as malignant (n = 136) or benign (n = 32). The dataset was randomly divided into five subsets: four were used for augmentation and supervised training (48,832 images), and one was used for testing (281 images). The Inception-v3 architecture convolutional neural network (CNN) model was used. The AUC for malignancy and accuracy at optimal cutoff values of output data were evaluated in six different CNN models. Multivariate logistic regression analysis was also performed. RESULTS. Malignant and benign lesions showed no significant difference of size. The AUC value of corticomedullary phase was higher than that of other phases (corticomedullary vs excretory, p = 0.022). The highest accuracy (88%) was achieved in corticomedullary phase images. Multivariate analysis revealed that the CNN model of corticomedullary phase was a significant predictor for malignancy compared with other CNN models, age, sex, and lesion size. CONCLUSION. A deep learning method with a CNN allowed acceptable differentiation of small (≤ 4 cm) solid renal masses in dynamic CT images, especially in the corticomedullary image model.

Post-ablation syndrome after percutaneous cryoablation of small renal tumors: A prospective study of incidence, severity, duration, and effect on lifestyle.

PURPOSE: To prospectively investigate the incidence, severity, duration, and effect on lifestyle of post-ablation syndrome (PAS) after percutaneous renal cryoablation. MATERIALS AND METHODS: We enrolled 39 patients (27 male and 12 female; mean age, 62 years) who underwent 40 CT-guided cryoablation sessions for pathologically proven renal cancer (mean size, 20 mm) between December 2015 and December 2017. Four symptoms attributable to PAS, i.e., fever, nausea, vomiting, malaise, and the synergistic effect of these symptoms on lifestyle by 21 days after ablation were evaluated using a questionnaire. Symptoms were graded according to the common toxicity criteria of adverse events. RESULTS: The incidences of fever, nausea, vomiting, and malaise were 100% (40/40), 20% (8/40), 20% (8/40), and 63% (25/40), respectively. Most (78/81, 96%) symptoms had begun by day 2. The highest grade of fever per session was 0 (defined as ≥37.0 °C and <38.0 °C) (n = 24), 1 (n = 15), or 2 (n = 1); that of nausea was 2 (n = 8); that of vomiting was 1 (n = 7) or 3 (n = 1); and that of malaise was 1 (n = 14) or 2 (n = 11). Most (76/81, 94%) symptoms had resolved by day 8. The average values for the maximum scores of interference with general activity and work were 3.6 and 1.1, respectively. CONCLUSION: All symptoms were generally early-onset and self-limiting, with minimal impact on lifestyle and resolution by day 8. The clinical course and impact of PAS should be acknowledged by practitioners who manage patients undergoing renal cryoablation.

Imaging an intrapulmonary solitary fibrous tumor with CT and F-18 FDG PET/CT.

Intrapulmonary solitary fibrous tumors (SFTs) are extremely rare neoplasms. We report a case of an intrapulmonary SFT and describe the findings of computed tomography (CT) and F-18 fluorodeoxyglucose positron emission tomography. The case indicates that a benign intrapulmonary SFT can present as a ground-glass nodule in the early stages of disease and may appear as a well-defined, lobular, homogeneously enhanced mass with slow growth on chest CT images. To our knowledge, this is the first report describing the natural course of an intrapulmonary SFT over 16 years based on the findings of chest CT and F-18 fluorodeoxyglucose positron emission tomography/CT.

Chemoradiotherapy for locally advanced lung cancer patients with interstitial lung abnormalities.

INTRODUCTION: Although chemoradiotherapy for locally advanced lung cancer has the potential for cure, treatment is avoided in patients with interstitial lung disease because of the risk for severe radiation pneumonitis. Interstitial lung abnormalities (ILA) can be evaluated using high-resolution computed tomography (HRCT) to assess interstitial changes. In this study, we retrospectively examined the feasibility and efficacy of chemoradiotherapy for locally advanced lung cancer patients with ILA. METHODS: Patients who underwent chemoradiotherapy for locally advanced lung cancer at Okayama University Hospital between 2012 and 2015 were reviewed retrospectively. HRCT prior to treatment was evaluated by one pulmonologist and two radiologists using a sequential reading method. RESULTS: Of the 77 patients enrolled in this study, ILA was present in 25 (32.5%) and indeterminate ILA in 24 patients; 28 patients did not have ILA. Desaturation at rest (SpO2 < 95%) and honeycombing on HRCT were not observed in ILA patients. Only one patient with ILA had a low vital capacity (%VC < 80%). Severe radiation pneumonitis (≥Grade 2) occurred in 36.0% of the patients with ILA, but it was controllable; Grade 4 or 5 was not observed. Multivariate analysis showed that >25% of the lung volume receiving >20 Gy was risk factors of severe radiation pneumonitis, but ILA was not. The 2-year survival rates of patients with and without ILA were 56.8% and 74.1%, respectively, but the difference was not significant (P = 0.33). CONCLUSIONS: Chemoradiotherapy was feasible and effective in some patient population with ILA without desaturation, low VC and honeycombing on HRCT.

A rapid caliber change in the inferior vena cava during multiphasic contrast-enhanced computed tomography may signal an acute anaphylactic reaction to nonionic contrast medium.

Severe anaphylactic reactions to an intravenous nonionic iodine contrast medium (NICM) are uncommon but can result in permanent morbidity or death if not managed appropriately. An anaphylactic reaction to an NICM typically manifests as clinical symptoms that include an itchy nose, sneezing, and skin redness. To our knowledge, a rapid change in the caliber of the inferior vena cava (IVC) during multiphasic contrast-enhanced computed tomography (CT) has not been reported. Here, we report the computed tomographic findings in three cases of hypovolemic shock caused by an anaphylactic reaction to an NICM. We suspect that a decrease in caliber of the IVC during multiphasic contrast-enhanced CT may be a predictor of an allergic-like reaction to an NICM. Patients in whom physicians and radiographers detect a rapid caliber change in the IVC during multiphasic contrast-enhanced CT should be managed carefully.

Delayed hydronephrosis due to retroperitoneal hematoma after a seatbelt injury: A case report.

RATIONALE: Hydronephrosis caused by retroperitoneal hematoma after a seatbelt injury is a unique clinical entity. PATIENT CONCERNS: A 21-year-old man, who had been wearing a seatbelt, was brought to our hospital after a motor vehicle collision, complaining of abdominal pain. Computed tomography (CT) revealed retroperitoneal hematoma in the upper pelvic region. Since he was hemodynamically stable throughout admission, he was managed conservatively. Seventeen days after initial discharge, the patient revisited our emergency department due to right back pain. DIAGNOSES: CT scans indicated retroperitoneal hematoma growth resulting in hydronephrosis of the right kidney. INTERVENTIONS: Laparoscopic drainage of the retroperitoneal hematoma was successfully performed. OUTCOMES: His symptoms resolved after the surgery. Follow-up CT scans three months later demonstrated complete resolution of the hydronephrosis and retroperitoneal hematoma. LESSONS: Our case highlights a patient with delayed hydronephrosis because of retroperitoneal hematoma expansion after a seatbelt injury.

Utility of second-generation single-energy metal artifact reduction in helical lung computed tomography for patients with pulmonary arteriovenous malformation after coil embolization.

PURPOSE: The quality of images acquired using single-energy metal artifact reduction (SEMAR) on helical lung computed tomography (CT) in patients with pulmonary arteriovenous malformation (PAVM) after coil embolization was retrospectively evaluated. MATERIALS AND METHODS: CT images were reconstructed with and without SEMAR. Twenty-seven lesions [20 patients (2 males, 18 females), mean age 61.2 ± 11.0 years; number of embolization coils, 9.8 ± 5.0] on contrast-enhanced CT and 18 lesions of non-enhanced lung CT concurrently performed were evaluated. Regions of interest were positioned around the coils and mean standard deviation value was compared as noise index. Two radiologists visually evaluated metallic coil artifacts using a four-point scale: 4 = minimal; 3 = mild; 2 = strong; 1 = extensive. RESULTS: Noise index was significantly improved with SEMAR versus without SEMAR (median [interquartile range]; 194.4 [161.6-211.9] Hounsfield units [HU] vs. 243.9 [220.4-286.0] HU; p < 0.001). Visual score was significantly improved with SEMAR versus without SEMAR (Reader 1, 3 [3] vs.1 [1]; Reader 2, 3 [3] vs.1 [1]; p < 0.001). Significant differences were similarly demonstrated on lung CT (p < 0.001). CONCLUSION: SEMAR provided clear chest CT images in patients who underwent PAVM coil embolization.

CT fluoroscopy-guided renal tumour cutting needle biopsy: retrospective evaluation of diagnostic yield, safety, and risk factors for diagnostic failure.

OBJECTIVES: To evaluate retrospectively the diagnostic yield, safety, and risk factors for diagnostic failure of computed tomography (CT) fluoroscopy-guided renal tumour biopsy. METHODS: Biopsies were performed for 208 tumours (mean diameter 2.3 cm; median diameter 2.1 cm; range 0.9-8.5 cm) in 199 patients. One hundred and ninety-nine tumours were ≤4 cm. All 208 initial procedures were divided into diagnostic success and failure groups. Multiple variables related to the patients, lesions, and procedures were assessed to determine the risk factors for diagnostic failure. RESULTS: After performing 208 initial and nine repeat biopsies, 180 malignancies and 15 benign tumours were pathologically diagnosed, whereas 13 were not diagnosed. In 117 procedures, 118 Grade I and one Grade IIIa adverse events (AEs) occurred. Neither Grade ≥IIIb AEs nor tumour seeding were observed within a median follow-up period of 13.7 months. Logistic regression analysis revealed only small tumour size (≤1.5 cm; odds ratio 3.750; 95% confidence interval 1.362-10.326; P = 0.011) to be a significant risk factor for diagnostic failure. CONCLUSION: CT fluoroscopy-guided renal tumour biopsy is a safe procedure with a high diagnostic yield. A small tumour size (≤1.5 cm) is a significant risk factor for diagnostic failure. KEY POINTS: • CT fluoroscopy-guided renal tumour biopsy has a high diagnostic yield. • CT fluoroscopy-guided renal tumour biopsy is safe. • Small tumour size (≤1.5 cm) is a risk factor for diagnostic failure.

Preoperative short hookwire placement for small pulmonary lesions: evaluation of technical success and risk factors for initial placement failure.

OBJECTIVES: To retrospectively evaluate the technical success of computed tomography fluoroscopy-guided short hookwire placement before video-assisted thoracoscopic surgery and to identify the risk factors for initial placement failure. METHODS: In total, 401 short hookwire placements for 401 lesions (mean diameter 9.3 mm) were reviewed. Technical success was defined as correct positioning of the hookwire. Possible risk factors for initial placement failure (i.e., requirement for placement of an additional hookwire or to abort the attempt) were evaluated using logistic regression analysis for all procedures, and for procedures performed via the conventional route separately. RESULTS: Of the 401 initial placements, 383 were successful and 18 failed. Short hookwires were finally placed for 399 of 401 lesions (99.5%). Univariate logistic regression analyses revealed that in all 401 procedures only the transfissural approach was a significant independent predictor of initial placement failure (odds ratio, OR, 15.326; 95% confidence interval, CI, 5.429-43.267; p < 0.001) and for the 374 procedures performed via the conventional route only lesion size was a significant independent predictor of failure (OR 0.793, 95% CI 0.631-0.996; p = 0.046). CONCLUSIONS: The technical success of preoperative short hookwire placement was extremely high. The transfissural approach was a predictor initial placement failure for all procedures and small lesion size was a predictor of initial placement failure for procedures performed via the conventional route. KEY POINTS: • Technical success of preoperative short hookwire placement was extremely high. • The transfissural approach was a significant independent predictor of initial placement failure for all procedures. • Small lesion size was a significant independent predictor of initial placement failure for procedures performed via the conventional route.

Robotically Driven CT-guided Needle Insertion: Preliminary Results in Phantom and Animal Experiments.

Purpose To evaluate the accuracy of the remote-controlled robotic computed tomography (CT)-guided needle insertion in phantom and animal experiments. Materials and Methods In a phantom experiment, 18 robotic and manual insertions each were performed with 19-gauge needles by using CT fluoroscopic guidance for the evaluation of the equivalence of accuracy of insertion between the two groups with a 1.0-mm margin. Needle insertion time, CT fluoroscopy time, and radiation exposure were compared by using the Student t test. The animal experiments were approved by the institutional animal care and use committee. In the animal experiment, five robotic insertions each were attempted toward targets in the liver, kidneys, lungs, and hip muscle of three swine by using 19-gauge or 17-gauge needles and by using conventional CT guidance. The feasibility, safety, and accuracy of robotic insertion were evaluated. Results The mean accuracies of robotic and manual insertion in phantoms were 1.6 and 1.4 mm, respectively. The 95% confidence interval of the mean difference was -0.3 to 0.6 mm. There were no significant differences in needle insertion time, CT fluoroscopy time, or radiation exposure to the phantom between the two methods. Effective dose to the physician during robotic insertion was always 0 µSv, while that during manual insertion was 5.7 µSv on average (P < .001). Robotic insertion was feasible in the animals, with an overall mean accuracy of 3.2 mm and three minor procedure-related complications. Conclusion Robotic insertion exhibited equivalent accuracy as manual insertion in phantoms, without radiation exposure to the physician. It was also found to be accurate in an in vivo procedure in animals. © RSNA, 2017 Online supplemental material is available for this article.

Disappearance of Renal Cysts Included in Ice Ball During Cryoablation of Renal-Cell Carcinoma: A Potential Therapy for Symptomatic Renal Cysts?

PURPOSE: To retrospectively evaluate the effect of cryoablation of renal-cell carcinoma on nearby renal cysts with the goal to investigate the potential for an alternative therapy to treat symptomatic renal cysts. MATERIALS AND METHODS: The study population comprised 46 cysts (mean size, 12 mm; range, 5-43 mm) that were within or near the ice ball during cryoablation in 22 patients. Size change of each cyst was evaluated via enhanced CT or MR imaging before and 1, 3, 6, and 12 months after cryoablation. Forty-one cysts were also followed after 12 months. Variables including positional relationship between the cyst and the ice ball were evaluated via linear regression analysis using generalized estimating equation models to determine which factors affected cyst shrinkage rate at 12 months. RESULTS: Fifteen, 12, and 19 cysts were completely included in, partially included in, or excluded from the ice ball, respectively. The overall shrinkage rate was 62%, and 57% of cysts (26 of 46) had disappeared at 12 months. Only the relationship between the cyst and the ice ball was significantly (P < .001) associated with cyst shrinkage rate. Cyst disappearance rates at 12 months were 100% (15 of 15), 67% (8 of 12), and 16% (3 of 19) for cysts completely included, partially included, and excluded from the ice ball, respectively. Among the 22 cysts that disappeared at 12 months and continued to be followed, none recurred after 12 months. CONCLUSIONS: All renal cysts that were completely included in the ice ball disappeared after cryoablation, demonstrating the potential utility of cryoablation as an alternative therapy for symptomatic renal cysts.

Imaging of the temporal bone in children using low-dose 320-row area detector computed tomography.

INTRODUCTION: The aim of this study was to compare the image quality obtained using low-dose and standard-dose 320-row temporal bone computed tomography (CT) in paediatric patients. METHODS: Thirteen low-dose CT (120 kV/50 mAs) and nine standard-dose CT (120 kV/100 mAs) images from children up to 5 years of age were compared for their image quality. The noise and signal-to-noise ratio for bone, fat and air were measured. Two observers assessed the overall image quality and ability to visualize 14 small anatomic structures using a 5-point scale, with a score of 3-5 indicating imaging of diagnostic quality. RESULTS: Noise was significantly higher and the signal-to-noise ratio was significantly lower with low-dose CT. Although the overall image quality and visibility of several structures on low-dose CT were significantly reduced when compared with standard-dose CT, all the image quality scores were 3 or >3. The dose-length products for low-dose CT and standard-dose CT were 59.6 mGy·cm and 119.3 mGy·cm, respectively. CONCLUSION: Low-dose CT of the temporal bone using 320-row CT provides images of diagnostic quality for assessment of middle and inner ear anatomy, similar to that provided by the standard-dose protocol, in spite of increased image noise.

Safety of Percutaneous Cryoablation in Patients with Painful Bone and Soft Tissue Tumors: A Single Center Prospective Study (SCIRO-1502).

This single center prospective study is being conducted to evaluate the safety of the cryoablation for patients with pathologically diagnosed painful bone and soft tissue tumors. Enrollment of 10 patients is planned over the 3-year recruitment period. Patients have related local pain after receiving medications or external radiation therapies will be included in this study. Cryoablation will be percutaneously performed under imaging guidance, and a temperature sensor will be used during treatment as necessary. The primary endpoint is prevalence of severe adverse events within 4 weeks after therapy. The secondary endpoint is effectiveness 4 weeks after the procedure.

Fever after lung radiofrequency ablation: Prospective evaluation of its incidence and associated factors.

PURPOSE: To prospectively investigate the incidence of post-lung radiofrequency (RF) ablation fever as well as its associated factors, according to the grade of fever. MATERIALS AND METHODS: A total of 56 patients who underwent 67 lung RF sessions were analyzed. Post-ablation fever (≥ 37.0°C) was graded according to the common toxicity criteria of adverse events v. 4.0. Fever ≥ 37.0°C and <38.0°C was defined as grade 0 fever. The 67 RF sessions were divided into two groups according to the presence of post-ablation fever, and the factors associated with fever were determined using univariate and multivariate analyses. Subsequently, the RF sessions accompanied by post-ablation fever were further divided into two groups according to the grade of fever (grade 0 vs. grade ≥ 1), and the factors associated with the grade of fever were determined. RESULTS: Grade 0, 1, and 2 fever accompanied 36 (54%), 11 (16%), and 2 (3%) sessions, respectively. Post-ablation fever was significantly associated with larger ablated parenchymal volume (P=0.001) and development of pulmonary infiltration (P=0.004). Additionally, development of pulmonary infiltration (P=0.048) was also significantly and independently associated with higher grade of fever in the multivariate analysis. CONCLUSIONS: The incidences of grade 0, 1, and 2 post-ablation fever were 54%, 16%, and 3%, respectively. Larger ablated parenchymal volume and development of pulmonary infiltration were found to be associated with the development of post-ablation fever, with the latter being an independent factor associated with higher grade of fever.

Phrenic nerve injury after radiofrequency ablation of lung tumors: retrospective evaluation of the incidence and risk factors.

PURPOSE: To retrospectively investigate the incidence of and risk factors for phrenic nerve injury after radiofrequency (RF) ablation of lung tumors. MATERIALS AND METHODS: The study included 814 RF ablation procedures of lung tumors. To evaluate the development of phrenic nerve injury, chest radiographs obtained before and after the procedure were examined. Phrenic nerve injury was assumed to have developed if the diaphragmatic level was elevated after the procedure. To identify risk factors for phrenic nerve injury, multiple variables were compared between cases of phrenic nerve injury and randomly selected controls by using univariate analyses. Multivariate analysis was then performed to identify independent risk factors. RESULTS: Evaluation of phrenic nerve injury from chest radiographs was possible after 786 procedures. Evidence of phrenic nerve injury developed after 10 cases (1.3%). Univariate analysis revealed that larger tumor size (≥ 20 mm; P = .014), proximity of the phrenic nerve to the tumor (< 10 mm; P < .001), the use of larger electrodes (array diameter or noninsulated tip length ≥ 3 cm; P = .001), and higher maximum power applied during ablation (≥ 100 W; P < .001) were significantly associated with the development of phrenic nerve injury. Multivariate analysis demonstrated that the proximity of the phrenic nerve to the tumor (< 10 mm; P < .001) was a significant independent risk factor. CONCLUSIONS: The incidence of phrenic nerve injury after RF ablation was 1.3%. The proximity of the phrenic nerve to the tumor was an independent risk factor for phrenic nerve injury.