Comparative evaluation of shear wave elastography elasticity values in thyroid nodules with cytology results and TI-RADS scoring in differentiation of benign-malignant nodules.

PURPOSE: The aim of this prospective study was to investigate the diagnostic performance of shear wave elastography (SWE) in differentiating benign and malignant thyroid nodules and their correlation with the American College of Radiology Thyroid Imaging Reporting and Data System (ACR TI-RADS). METHODS: This prospective study included 370 thyroid nodules in 308 patients aged 18-70 years. All the patients underwent B-mode ultrasound (US), Doppler examination, and SWE and were given an ACR TI-RADS risk score before fine needle aspiration biopsy (FNAB) and/or surgery. The correlation between SWE parameters and ACR TI-RADS categories was investigated statistically and compared with histopathologic results. Additionally, the diagnostic performance of SWE was evaluated to distinguish malignant and benign thyroid nodules. RESULTS: One hundred and thirty-five of the 370 thyroid nodules were malignant, and 235 nodules were benign. The mean shear wave velocity (SWV) value of the malignant nodules (3.70 ± 0.98 m/s) was statistically higher than that of the benign nodules (2.70 ± 0.37 m/s). The best cutoff value of the mean SWV for differentiating benign and malignant nodules was found to be 2.94 m/s (sensitivity 90.4%, specificity 89.9%, positive predictive value 81.3%, negative predictive value 94.1%, p < 0.001). The average score of the nodules according to the ACR TI-RADS was 3.57 ± 1.83 in benign nodules and 7.38 ± 2.69 in malignant nodules (p ≤ 0.001). CONCLUSION: This study showed that combining SWE and TI-RADS improves the specificity of TI-RADS alone in differentiating benign and malignant nodules.

Diffusion-weighted MRI at 3T in Endometrial Cancer: Correlation of Apparent Diffusion Coefficient with Histopathological Prognostic Parameters.

OBJECTIVE: To evaluate the value of apparent diffusion coefficient (ADC) for the differentiation of histological subtypes in endometrial cancer, and to assess if ADC values correlate with histopathological parameters. STUDY DESIGN: Descriptive study. PLACE AND DURATION OF STUDY: Department of Radiology, Faculty of Medicine, Ondokuz Mayis University between January 2016 and December 2019. METHODOLOGY: Eighty-three patients (mean age: 60.28 ± 9.07) with endometrial cancer underwent diffusion-weighted imaging (DWI) at 3T before surgery. The mean ADC (ADCmean) and minimum ADC (ADCmin) values of the tumours were assessed to predict histological subtype of endometrial cancer, grade of tumour, presence of myometrial invasion, lower uterine segment involvement, cervical involvement, lymphovascular invasion, and lymph node metastasis. RESULTS: Sixty patients (72.3%) were diagnosed with endometrioid carcinoma, and 23 patients (27.7%) were diagnosed with non-endometrioid carcinoma. The median ADCmean/ADCmin of endometrioid and non-endometrioid tumours were 0.72/0.58 ×10-3 mm2/s and 0.82/0.63 ×10-3 mm2/s, respectively. ADCmean and ADCmin were significantly different between endometrioid and non-endometrioid tumours (p=0.016 and p=0.048). For the endometrioid carcinomas, ADCmean and ADCmin were significantly different between low-grade (G1 and G2) and high-grade (G3) tumours (ADCmean/ADCmin = 0.75/0.65 vs. 0.59/0.49 x10-3 mm2/s, p=0.010 and p=0.013). Myometrial invasion, lymphovascular invasion, cervical involvement, lower uterine involvement, serosal involvement and lymph node metastasis were not significantly associated with ADC values. CONCLUSION: ADC measurements were useful for differentiating endometrioid and non-endometrioid carcinomas. High-grade endometrioid carcinomas had significantly lower ADC values compared to low-grade ones. Key Words: Endometrial cancer, Diffusion-weighted MRI, Apparent diffusion coefficient, Prognostic factors, Histological grade.

Comparison of 5 Thyroid Ultrasound Stratification Systems for Differentiation of Benign and Malignant Nodules and to Avoid Biopsy Using Histology as Reference Standard.

OBJECTIVE: We aimed to compare the thyroid ultrasound risk stratification systems (RSSs) of the American College of Radiology (ACR) Thyroid Imaging Reporting and Data System (TI-RADS), European TI-RADS, Korean TI-RADS, and American Thyroid Association (ATA), American Association of Clinical Endocrinologists, American College of Endocrinology, and Associazione Medici Endocrinologi guidelines to differentiate benign from malignant thyroid nodules and to avoid unnecessary fine needle aspiration (FNA). METHODS: The records of 1143 nodules ≥1 cm that underwent FNA biopsy and thyroidectomy between 2012 and 2020 at our institution were reviewed. Ultrasound categories and FNA recommendation indications of 5 international RSSs were compared with histopathological findings as benign or malignant. The ultrasound categories and recommended FNA indications, the proportion of the avoidable FNA procedures, and false negative rates (FNRs) by different systems were compared with each other. RESULTS: Of the 1143 nodules, 45% had thyroid malignancy. FNA recommendation and ultrasound risk classification of ATA guidelines had the highest area under curves of 0.619, and 0.715, respectively. ACR TI-RADS, American Association of Clinical Endocrinologists/American College of Endocrinology/Associazione Medici Endocrinologi guidelines, European TI-RADS, ATA guidelines, and Korean TI-RADS would have avoided FNA for 34.7%, 31%, 25.7%, 20%, and 6% of nodules with an FNR of 24%, 28.5%, 22%, 7.2%, and 1.9%, respectively. CONCLUSION: Our findings showed that all RSSs classified the nodules appropriately for malignancy. ATA guidelines had the highest area under curves and a low FNR, whereas ACR TI-RADS would have spared more patients from FNA with a high FNR.

Discrimination of papillary renal cell carcinoma from benign proteinaceous cyst based on iodine and water content on rapid kV-switching dual-energy CT.

PURPOSE: We aimed to evaluate whether rapid kV-switching dual energy CT (rsDECT) can discriminate between papillary renal cell carcinoma (RCC) and benign proteinaceous cysts (BPCs) based on iodine and water content. METHODS: Twenty-four patients with histopathologically proven papillary RCC and 38 patients with 41 BPCs were retrospectively included. Patients with BPCs were eligible for inclusion when the cysts were stable in size and appearance for at least 2 years or proved to be a cyst on ultrasound or MRI. All patients underwent delayed phase (70-90 s) rsDECT. Iodine and water content of each lesion was measured on the workstation. RESULTS: Of papillary RCC patients, 4 (16%) were female and 20 (84%) were male. Mean tumor size was 39±20 mm. Mean iodine and water content was 2.08±0.7 mg/mL and 1021±14 mg/mL, respectively. Of BPC patients, 9 were female and 29 were male. Mean cyst size was 20±7 mm. Mean iodine and water content was 0.82±0.4 mg/mL and 1012±14 mg/mL, respectively. There were significant differences between iodine and water contents of papillary RCCs and BPCs (P < 0.001). The best cutoff of iodine content for differentiating papillary RCC from BPC was 1.21 mg/mL (area under the curve [AUC]=0.97, P < 0.001, sensitivity 96%, specificity 88%, positive predictive value [PPV] 82%, negative predictive value [NPV] 97%, accuracy 91%,); the best cutoff of water content was 1015.5 mg/mL (AUC=0.68, P = 0.016, sensitivity 83%, specificity 56%, PPV 52%, NPV 85%, accuracy 66%). CONCLUSION: An iodine content threshold of 1.21 mg/mL accurately differentiates papillary RCC from BPCs on a single postcontrast rsDECT. Despite having a high sensitivity, water content has inferior diagnostic accuracy.

Evaluation of artifacts generated by titanium, zirconium, and titanium-zirconium alloy dental implants on MRI, CT, and CBCT images: A phantom study.

OBJECTIVE: The aim of this study was to assess artifacts generated by zirconium, titanium, and titanium-zirconium alloy implants on magnetic resonance imaging(MRI), computed tomography(CT), and cone beam computed tomography(CBCT) and to correlate the findings to the dose-area product and exposure factors on CT and CBCT. STUDY DESIGN: Three phantoms were built by embedding zirconium, titanium, and titanium-zirconium implants in ultrasound gel. MRI, CT, and CBCT images were acquired by using multiple sequences and settings. For MRI, "artifact" was described as the length of signal void beyond the limits of the implant. For CT and CBCT, "artifact" was calculated by subtracting the gray level of the darkest pixel from the level of the lightest pixel. RESULTS: On MRI, zirconium implants had minor distortion artifacts, whereas titanium and titanium-zirconium implants created extensive artifacts (P < .05). On CT and CBCT, artifacts were less prominent with titanium and titanium-zirconium implants compared with zirconium (P < .05). Titanium grade 5 implants with 0.3 and 0.4 mm3 voxels produced the least severe artifacts. CONCLUSIONS: MRI images were less affected by artifacts from zirconium implants, whereas CT and CBCT images showed less severe artifacts from titanium and titanium-zirconium alloy implants. CT generated greater artifacts compared with CBCT. Larger CBCT voxel sizes reduced the dose-area product and the severity of artifacts.

Usefulness of rapid kV-switching dual energy CT in renal tumor characterization.

PURPOSE: To investigate whether iodine content can discriminate between benign or malignant renal tumors, malign tumor subtypes, low-grade and high-grade tumors on rapid kv-switching dual-energy CT (rsDECT). METHODS: This prospective study enrolled 95 patients with renal tumors who underwent rsDECT for tumor characterization between 2016 and 2018. Attenuation on true and virtual unenhanced images, absolute enhancement and enhancement ratio and iodine content of each lesion on nephrographic phase iodine density images were measured. Histopathological diagnosis was obtained following either surgery or core biopsy. RESULTS: Eighty-five tumors were renal cell carcinoma (RCC) (56 clear cell, 20 papillary, 9 chromophobe) and 10 were benign (6 angiomyolipoma,4 oncocytoma). 46 tumors were low-grade and 23 high-grade. There was significant difference between iodine content of clear cell and non-clear cell (papillary + chromophobe) RCC (p < 0.001). However, no significant iodine content differences were found between papillary and chromophobe RCC, benign and malignant tumors, low-grade and high-grade tumors. The best cut-off iodine content for differentiating clear cell from non-clear cell RCC was 3.2 mg/ml and clear cell from papillary RCC was 2.9 mg/ml with a high sensitivity and specificity. Also, significant difference was found between attenuation values of true and virtual unenhanced images (p = 0.007). Mean iodine content, absolute enhancement and enhancement ratio were highly correlated. CONCLUSION: rsDECT contributes to renal tumor characterization by showing higher iodine content in clear cell RCCs compared with non-clear cell RCCs.

Discrimination of oncocytoma and chromophobe renal cell carcinoma using MRI.

PURPOSE: We aimed to evaluate magnetic resonance imaging (MRI) features, including signal intensities, enhancement patterns and T2 signal intensity ratios to differentiate oncocytoma from chromophobe renal cell carcinoma (RCC). METHODS: This retrospective study included 17 patients with oncocytoma and 33 patients with chromophobe RCC who underwent dynamic MRI. Two radiologists independently reviewed images blinded to pathology. Morphologic characteristics, T1 and T2 signal intensities were reviewed. T2 signal intensities, wash-in, wash-out values, T2 signal intensity ratios were calculated. Sensitivity and specificity analyses were performed. RESULTS: Mean ages of patients with oncocytoma and chromophobe RCC were 61.0±11.6 and 58.5±14.0 years, respectively. Mean tumor size was 60.6±47.3 mm for oncocytoma, 61.7±45.9 mm for chromophobe RCC. Qualitative imaging findings in conventional MRI have no distinctive feature in discrimination of two tumors. Regarding signal intensity ratios, oncocytomas were higher than chromophobe RCCs. Renal oncocytomas showed higher signal intensity ratios and wash-in values than chromophobe RCCs in all phases. Fast spin-echo T2 signal intensities were higher in oncocytomas than chromophobe RCCs. CONCLUSION: Signal intensity ratios, fast spin-echo T2 signal intensities and wash-in values constitute diagnostic parameters for discriminating between oncoytomas and chromophobes. In the excretory phase of dynamic enhanced images, oncocytomas have higher signal intensity ratio than chromophobe RCC and high wash-in values strongly imply a diagnosis of renal oncocytoma.

Efficacy of perfusion CT in differentiating of pancreatic ductal adenocarcinoma from mass-forming chronic pancreatitis and characterization of isoattenuating pancreatic lesions.

PURPOSE: Multidetector computed tomography (MDCT) is routinely used in the diagnosis of pancreatic ductal adenocarcinoma (PDAC), but it may be inadequate in some cases, especially mass-forming chronic pancreatitis (MFCP) and isoattenuating pancreatic lesions. Perfusion CT (pCT) may help resolve this problem. The aim of this study was to evaluate whether pCT could help differentiating PDAC from MFCP and in characterization of isoattenuating pancreatic lesions. MATERIALS AND METHODS: This prospective study included 89 cases of pancreatic lesions detected by MDCT and further analyzed with pCT. Sixty-one cases with final pathological diagnosis PDAC and 12 cases with MFCP were included from the study. Blood volume (BV), blood flow (BF), mean transit time (MTT), and permeability surface area product (PS) maps were obtained. Perfusion values obtained from the lesions and normal parenchyma were compared. RESULTS: Compared with normal parenchyma, BV, BF, PS were lower and MTT was longer in PDAC and MFCP (p < 0.05). Compared with MFCP, BV, BF, PS were lower and MTT was longer in PDAC (p < 0.001). Compared with normal parenchyma, BV, BF, PS were lower and MTT was longer in isoattenuating lesions, (p < 0.001). Cutoff values of 7.60 mL/100 mL, 64.43 mL/100 mL/min, 28.08 mL/100 mL/min for BV, BF, PS, respectively, provided 100% sensitivity and specificity and 7.47 s for MTT provided 98.3% sensitivity, 80% specificity for distinguishing PDAC from MFCP. CONCLUSION: pCT is a useful technology that can be helpful in overcoming the limitations of routine MDCT in diagnosing PDAC and characterization of isoattenuating lesions.

A First Report of Synchronous Intracapsular and Extracapsular Hepatic Adenoma.

Although the gallbladder is the most common site of ectopic liver, it has been reported in many other organs, such as kidney, adrenal glands, pancreas, omentum, stomach, esophagus, mediastinum, lungs, and heart. Hepatocytes in an ectopic liver behave like normal hepatocytes; furthermore, they can be associated with the same pathological findings as those in the main liver. Ectopic liver in the gallbladder can undergo fatty change, hemosiderosis, cholestasis, cirrhosis, hemangioma, focal nodular hyperplasia, adenoma, and even carcinogenesis. The incidence of extracapsular hepatic adenoma is not known, but only two cases have been reported. Here, we provide the first case report of synchronous multiple intracapsular and extracapsular hepatic adenomas. A 60-year-old woman with multiple hepatic adenomas and one 7 × 5 × 5 cm ectopic hepatic adenoma attached to the gallbladder fundus complicated with abdominal pain is presented.

Caesarean Scar Choriocarcinoma: Ultrasound and Magnetic Resonance Imaging Findings.

Primary gestational choriocarcinoma in a uterine caesarean section scar (CSS) is an extremely rare entity, and its timely diagnosis and treatment is crucial in order to prevent related complications and metastatic disease. Herein, we report on a 33-year-old female who was referred to our department with an initial diagnosis of ectopic pregnancy. Transabdominal ultrasound and magnetic resonance imaging (MRI) demonstrated a nodular mass on CSS. The final histopathological diagnosis was CSS choriocarcinoma.

Comparison of intrahepatic vein-to-liver parenchyma and intercostal muscle-to-liver parenchyma strain ratios in the assessment of liver fibrosis: which one should we use?

PURPOSE: The aims of this study were to investigate whether there is a difference in diagnostic value between vein to parenchyma strain ratio (VPSR) and muscle to parenchyma strain ratio (MPSR). METHODS: VPSR and MPSR were calculated via sonoelastography, and were recorded for comparison with histopathology. ROC analysis, the Mann-Whitney U test, the Kruskal-Wallis test, and Spearman's rank correlation test were used for statistical analysis. RESULTS: The study included 59 cases of individuals who underwent biopsy (29 women, 30 men). When the threshold value for VPSR was set at 3.23, the sensitivity was 96.2% and the specificity was 83.3% (p < 0.001, F ≥ 1). When the threshold value was set at 3.01 for MPR, the sensitivity was 88.7% and the specificity was 83.3% (p < 0.001, F ≥ 1). The areas under the curve values were VPSR 0.95 and MPSR 0.92 for F ≥ 1, VPSR 0.94 and MPSR 0.92 for F ≥ 2, and VPSR 1.00 and MPSR 0.76 for F = 3 (p < 0.001). The Spearman's correlation coefficient was 0.75, and a high positive concordance was found between VPSR and MPSR (p < 0.001). CONCLUSIONS: In this study, a high positive correlation was observed between two strain ratios, and VPSR was found to be more reliable than MPSR in determining liver fibrosis.

Cholangiocarcinoma Arising from a Type VI Biliary Cyst: A Case Report and Review of the Literature.

Cystic dilatations of the cystic duct which are suggested as type VI biliary cysts are very rare and many of them go unrecognized or are confused with other cysts until the operation although they are obvious on imaging studies. They can present with fusiform or saccular dilatations and can be accompanied by common bile duct dilatations. It is important to identify these cysts as they share the same characteristics as the other biliary cyst types and can be complicated with malignancy. We herein present a very unusual case of a cholangiocarcinoma arising from a type VI biliary cyst in a 58-year-old female patient and review the literature. The patient presented with jaundice, weight loss, and abdominal pain. On imaging, the cystic duct and common bile duct were fusiformly dilated and had a wide communication. There was a mass filling the distal parts of both ducts. The patient was urgently operated on after perforation following ERCP. Histopathology was compatible with a type VI biliary cyst and an associated cholangiocarcinoma.

Can a b value of 500 be substituted for a b value of 1000 in the characterization of focal liver lesions?

PURPOSE: Comparison of two different b values in diffusion-weighted magnetic resonance imaging (DWI) for characterization of focal liver lesions. METHODS: A total of 174 focal liver lesions from 100 patients were analyzed using two different b values (500 and 1000 s/mm(2)). The DWI with b values of 500 s/mm(2) (DWI500) and 1000 s/mm(2) (DWI1000) were analyzed using the Mann-Whitney test, kappa statistic, and paired t test with respect to image quality. The statistically significant differences between DWI500 and DWI1000 in the characterization of the lesions with respect to the cutoff ADC values were evaluated via χ (2) test. RESULTS: DWI500 had the highest mean score in the qualitative evaluation of image quality (p < 0.0001) and the highest signal-to-noise ratio (8.7 ± 2.1; p < 0.0001). The sensitivity, specificity, and AUC for discriminating malignant from benign focal lesions on DWI500 and DWI1000 using cutoff ADC values of 1.54 × 10(-3) and 1.38 × 10(-3) s/mm(2) were 95.8%, 92.3%, 0.98, and 93.8%, 92.3%, 0.97, respectively. There was no statistically significant difference in sensitivity, specificity, and AUC values between DWI500 and DWI1000 with respect to the cutoff ADC values (p > 0.05). CONCLUSIONS: The image quality of DWI500 was better than that of DWI1000, and there was no significant difference between DWI500 and DWI1000 in the characterization of the lesions with respect to the cutoff ADC values. The b value of 500 s/mm(2) can be substituted for the b value of 1000 s/mm(2) in the characterization of focal liver lesions.

Comparison of muscle-to-nodule and parenchyma-to-nodule strain ratios in the differentiation of benign and malignant thyroid nodules: which one should we use?

OBJECTIVE: The aim of this study is to investigate the diagnostic accuracy of muscle-to-nodule strain ratio (MNSR) in the differentiation of benign and malignant thyroid nodules and to see if there was a difference between MNSR and parenchyma-to-nodule strain ratios (PNSR) in diagnosis. METHODS: A total of 106 consecutive patients (88 women and 18 men; age range 19-79 years) with thyroid nodules were prospectively examined using ultrasound and sonoelastography before the fine-needle aspiration biopsy. The mean MNSR and PNSR were calculated for each nodule and the elasticity score was determined according to four-point scoring system. RESULTS: According to the four-point scoring system, 44 of the 83 benign nodules had a score of one or two while 22 of the 23 malignant nodules had a score of three or four (p<0.001). Using ROC analysis, the best cutoff point for MNSR 1.85 and for PNSR 3.14 was calculated. The sensitivity and specificity for the MNSR were 95.6%, 92.8%, respectively; for the PNSR were 95.6%, 93.4%, respectively, when the best cutoff points were used (p<0.001). The κ value for the PNSR and MNSR methods was 0.87, which indicated an almost perfect agreement (p<0.001). CONCLUSIONS: Sonoelastography has a high diagnostic accuracy in the differentiation of benign and malignant thyroid nodules. There was no significant difference between MNSR and PNSR in the differentiation of benign and malignant thyroid nodules. Therefore, we think that MNSR could safely be used in situations where PNSR could not be used.

Efficiency of apparent diffusion coefficients in differentiation of colorectal tumor recurrences and posttherapeutical soft-tissue changes.

OBJECTIVE: To evaluate effectiveness of apparent diffusion coefficient (ADC) values measured by diffusion-weighted magnetic resonance imaging (DW-MRI) in differentiation of colorectal tumor recurrences and posttherapeutical soft tissue changes. METHODS: For this prospective study, 30 patients (22 males, 8 females; age range 30-81 years; mean age 61±12 years) who underwent surgery for colorectal tumors and had a mass detected by computed tomography (CT) and/or MRI during follow-up examinations were divided into 2 groups [17 patients (Group 1) with recurrence and 13 patients (Group 2) with benign fibrosis/granulation tissue]. Final diagnoses were based on histopathological examination in 14 patients and clinical follow-up at least 6 months in the remaining 16. In the latter, the diagnosis of recurrence was made in cases in which the lesion was larger on follow-up CT and MRI; recurrence was ruled out in cases of stable or shrinking lesions without any increase in tumor markers. DW-MRI was performed in the axial plane, for two different b values (b=0 and 800 s/mm(2)). The mean apparent diffusion coefficient (ADC) values were measured by manual delineation of regions of interest on ADC maps. RESULTS: The median ADC values were 1.07 × 10(-3)mm/s(2) (min: 0.82, max: 2.05) and 1.91 × 10(-3)mm/s(2) (min: 1.51, max: 2.22) in Groups 1 and 2, respectively. A statistically significant difference was detected between the two groups (P<0.001). When the threshold value used to determine whether the lesions recurred was 1.48 × 10(-3)mm/s(2) based on ROC analysis, the sensitivity was 82% and the specificity was 100%. There were three patients with a false-negative diagnosis, and the primary histopathological diagnosis of all was mucinous adenocarcinoma. CONCLUSIONS: Because recurrences in mucinous adenocarcinomas have high ADC values, they may show overlap with benign lesions. In the detection of the local recurrence of colorectal neoplasms, with the exception of mucinous adenocarcinomas, ADC measurements are reliable imaging techniques.

Ultrasonography in the evaluation of midpalatal suture in surgically assisted rapid maxillary expansion.

Surgically assisted rapid maxillary expansion (SARME), which combines orthodontics and surgery, is a well-established therapy for transverse maxillary hypoplasia in adults after sutural closure or completion of skeletal maturation. X-rays are usually the preferred monitoring technique for this treatment. Recently, ultrasound scanning has been used successfully in the follow-up of patients undergoing distraction osteogenesis. In this study, ultrasonography (US) was used in the evaluation of bone callus formation in the midpalatal suture in 3 patients undergoing SARME. For each patient, US was performed immediately after active expansion, at 2 and 4 months of the expansion period, at the removal of the expander 6 months later, and at 2 months after expander removal. The results indicated that US might be a useful and accurate method to assess bone fill in the midpalatal suture in patients undergoing SARME. However, further studies are necessary to clarify the US scores in a larger patient group undergoing SARME.

Keratocystic odontogenic tumor: case report with CT and ultrasonography findings.

Keratocystic odontogenic tumor (KCOT) is a benign odontogenic tumor with a potentially aggressive and infiltrative behavior. KCOT is most commonly occurred in mandible and demonstrate a unilocular, round, oval, scalloped radiolucent area, while large lesions may appear multilocular. An important characteristic of KCOT is its propensity to grow in an antero-posterior direction within medullary cavity of bone causing minimal expansion. Definitive diagnosis relies on histological examination. In this report, a KCOT that had an expansion both buccal and lingual cortical bone is described including its features in computed tomography and ultrasonographic exams. The lesion was removed surgically via an intraoral approach under local anesthesia and histologically reported as a KCOT.