MRI and PSMA PET/CT of Biochemical Recurrence of Prostate Cancer.

Prostate cancer may recur several years after definitive treatment, such as prostatectomy or radiation therapy. A rise in serum prostate-specific antigen (PSA) level is the first sign of disease recurrence, and this is termed biochemical recurrence. Patients with biochemical recurrence have worse survival outcomes. Radiologic localization of recurrent disease helps in directing patient management, which may vary from active surveillance to salvage radiation therapy, androgen-deprivation therapy, or other forms of systemic and local therapy. The likelihood of detecting the site of recurrence increases with higher serum PSA level. MRI provides optimal diagnostic performance for evaluation of the prostatectomy bed. Prostate-specific membrane antigen (PSMA) PET radiotracers currently approved by the U.S. Food and Drug Administration demonstrate physiologic urinary excretion, which can obscure recurrence at the vesicourethral junction. However, MRI and PSMA PET/CT have comparable diagnostic performance for evaluation of local recurrence after external-beam radiation therapy or brachytherapy. PSMA PET/CT outperforms MRI in identifying recurrence involving the lymph nodes and bones. Caveats for use of both PSMA PET/CT and MRI do exist and may cause false-positive or false-negative results. Hence, these techniques have complementary roles and should be interpreted in conjunction with each other, taking the patient history and results of any additional prior imaging studies into account. Novel PSMA agents at various stages of investigation are being developed, and preliminary data show promising results; these agents may revolutionize the landscape of prostate cancer recurrence imaging in the future. ©RSNA, 2023 Quiz questions for this article are available through the Online Learning Center. See the invited commentary by Turkbey in this issue. The slide presentation from the RSNA Annual Meeting is available for this article.

Evaluation of Multiparametric Shear Wave Elastography Indices in Malignant and Benign Breast Lesions.

RATIONALE AND OBJECTIVES: To evaluate the shear wave elastography indices (multiparametric SWE) of breast lesions based on patient and lesion dependent features and assess the contribution of different elastographic parameters to radiological diagnosis. MATERIALS AND METHODS: Effect of patient-dependent (age and menopausal status) and lesion-dependent (distance from the areola, quadrant location, size, depth, margin and shape) factors on SWE parameters (Vmean, Vsd, Vmax, Vmin) in benign breast lesions were assessed. Only mass lesions were included in the study. Sensitivity, specificity, PPV, NPV and cut-off values for each elastography parameter was calculated. RESULTS: A total of 496 mass lesions of breast were evaluated. 467 of the lesions were benign and 29 were malignant. There was no significant relationship among SWE indices and age, menopausal status, lesion shape and distance to the areola in benign lesions (p>0.05). SWE indices were found to be associated with lesion margin, depth from the skin, and lesion size in benign lesions (p<0.05). All BI-RADS 3 lesions that underwent biopsy were benign (n:35); 23.5% of 4a lesions were malignant (n:4/17) and all 4b-4c-5 lesions were malignant (n:25/25). The cut-off values for malignant lesions were: Vmean 3.38 m/s, Vsd 0.81, Vmax 6.87 m/s, Vmin 1.53 m/s. All SWE parameters were statistically significant in predicting malignancy on ROC analysis, Vmax was the most sensitive (96.3%) and specific (94.7%) parameter. Cut-off values for Vmax was 6.87 m/s with an accuracy rate of 94.7%, and 3.37 m/s for Vmean and 0.8 for Vsd with 92.5% accuracy. CONCLUSION: The SWE parameters to predict malignancy in breast lesions can be affected by lesion dependent features, whereas no significant effect of patient's age or menopausal status on stiffness of the lesions was observed. Vmax had the highest sensitivity for predicting malignancy.

Machine Learning-Based Multiparametric Magnetic Resonance Imaging Radiomics for Prediction of H3K27M Mutation in Midline Gliomas.

OBJECTIVE: H3K27M mutation in gliomas has prognostic implications. Previous magnetic resonance imaging (MRI) studies have reported variable rates of tumoral enhancement, necrotic changes, and peritumoral edema in H3K27M-mutant gliomas, with no distinguishing imaging features compared with wild-type gliomas. We aimed to construct an MRI machine learning (ML)-based radiomic model to predict H3K27M mutation in midline gliomas. METHODS: A total of 109 patients from 3 academic centers were included in this study. Fifty patients had H3K27M mutation and 59 were wild-type. Conventional MRI sequences (T1-weighted, T2-weighted, T2-fluid-attenuated inversion recovery, postcontrast T1-weighted, and apparent diffusion coefficient maps) were used for feature extraction. A total of 651 radiomic features per each sequence were extracted. Patients were randomly selected with a 7:3 ratio to create training (n = 76) and test (n = 33) data sets. An extreme gradient boosting algorithm (XGBoost) was used in ML-based model development. Performance of the model was assessed by area under the receiver operating characteristic curve. RESULTS: Pediatric patients accounted for a larger proportion of the study cohort (60 pediatric [55%] vs. 49 adult [45%] patients). XGBoost with additional feature selection had an area under the receiver operating characteristic curve of 0.791 and 0.737 in the training and test data sets, respectively. The model achieved accuracy, precision (positive predictive value), recall (sensitivity), and F1 (harmonic mean of precision and recall) measures of 72.7%, 76.5%, 72.2%, and 74.3%, respectively, in the test set. CONCLUSIONS: Our multi-institutional study suggests that ML-based radiomic analysis of multiparametric MRI can be a promising noninvasive technique to predict H3K27M mutation status in midline gliomas.

Effect of Quantitative and Semi-quantitative Elastography Methods for the Management of Borderline Lesions on Ultrasonography.

BACKGROUND: Elastography (strain or shear-wave) is a method that estimates tissue stiffness. INTRODUCTION: The aim of this study is to evaluate the quantitative and semi-quantitative ultrasound elastography methods for the diagnosis of BI-RADS 4a and BI-RADS 3 lesions, which are borderline for biopsy and follow-up. MATERIALS AND METHODS: 175 consecutive women with 193 ultrasound-visible breast lesions were classified on Conventional B-mode Ultrasonography (CUS) according to the BI-RADS scoring system. Quantitative and semiquantitative values from ultrasound elastography in the form of strain Elastography Ratio (SER), shear Wave Elastography (SWE) and Shear Wave Elastography Ratio (SWER) were obtained. The lesions categorized as BI-RADS 4a and BI-RADS 3 on ultrasound were subsequently re-categorized according to the elastography values. RESULTS: Except for the 13 BI-RADS 2 lesions, the remaining 180 lesions were biopsied. Pathology showed 83 lesions to be benign and 97 to be malignant. The sensitivity and specificity of the CUS were 96.9% and 75.0%, respectively with an accuracy of 86.0%. Cut-off points calculated based on ROC curves were 56.8 kPa for SWE, 3.53 for SWER and 3.81 for SER. When we downgraded BIRADS 4a lesions based on elastography results, the specificity (CUS+SER 96.9%, CUS+SWE 91.7%, and CUS+SWER 90.6%) and the accuracy (CUS+SER 95.3%, CUS+SWE 92.7%, and CUS+SWER 92.2%) were shown to be better than CUS. When we upgraded BI-RADS 3 lesions based on elastography results, the sensitivity of combined sets of SWE (99,0%) and SWER (100,0%) was better than CUS. CONCLUSION: The rate of false-negative biopsies can be decreased with the combined use of elastography and ultrasonography.

The temporal course of COVID-19 anosmia and relation to other clinical symptoms.

OBJECTIVE: This study aimed to define the clinical course of anosmia in relation to other clinical symptoms. METHODS: 135 patients with COVID-19 were reached by phone and subsequently included in the study. Olfactory functions were evaluated using a questionnaire for assessment of self-reported olfactory function. Patients were divided into four subgroups according to the presence of olfactory symptoms and temporal relationship with the other symptoms: group1 had only olfactory complaints (isolated, sudden-onset loss of smell); group2 had sudden-onset loss of smell, followed by COVID-19 related complaints; group3 initially had COVID-19 related complaints, then gradually developed olfactory complaints; and group4 had no olfactory complaints. RESULTS: In total, 59.3% of the patients interviewed had olfactory complaints during the disease course. The olfactory dysfunction severity during COVID-19 infection was significantly higher in group1 compared to groups 2 and 3. In groups1-3, the odor scores after recovery from COVID-19 disease were significantly lower compared to the status prior to disease onset. The residual olfactory dysfunction was similar between groups1 and 2, but was more evident than group3. Mean duration for loss of smell was 7.8 ± 3.1 (2-15) days. Duration of loss of smell was longer in groups1 and 2 than in group3. Odor scores completely returned back to the pre-disease values in 41 (51.2%) patients with olfactory dysfunction. Rate of complete olfactory dysfunction recovery was higher in group3 compared to groups1 and 2. CONCLUSION: In isolated anosmia cases, anosmia is more severe, and complete recovery rates are lower compared to the patients who have other clinical symptoms. LEVEL OF EVIDENCE: Level 4.

Relationship between disease severity and serum IL-6 levels in COVID-19 anosmia.

BACKGROUND: An association between IL-6 levels and cytokine storm syndrome in COVID-19 patients has been suggested. Cases with higher IL-6 levels have more rapid progression and a higher complication rate. On the other hand, COVID-19 cases with anosmia have a milder course of the disease. OBJECTIVE: We aimed to investigate whether there is a relationship between serum IL-6 levels and presence of anosmia in COVID-19 patients. METHODS: Patients with a confirmed diagnosis of COVID-19 based on laboratory (PCR) were stratified into two groups based on presence of olfactory dysfunction (OD). In all cases with and without anosmia; psychophysical test (Sniffin' Sticks test) and a survey on olfactory symptoms were obtained. Threshold (t) - discrimination (d) - identification (i), and total (TDI) scores reflecting olfactory function were calculated. Clinical symptoms, serum IL-6 levels, other laboratory parameters, and chest computed tomography (CT) findings were recorded. RESULTS: A total of 59 patients were included, comprising 23 patients with anosmia and 36 patients without OD based on TDI scores. Patients with anosmia (41.39 ± 15.04) were significantly younger compared to cases without anosmia (52.19 ± 18.50). There was no significant difference between the groups in terms of comorbidities, smoking history, and symptoms including nasal congestion and rhinorrhea. Although serum IL-6 levels of all patients were above normal values (7 pg/mL), patients with anosmia had significantly lower serum IL-6 levels (16.72 ± 14.28 pg/mL) compared to patients without OD (60.95 ± 89.33 pg/mL) (p = 0.026). CONCLUSION: Patients with COVID-19 related anosmia tend to have significantly lower serum levels of IL-6 compared to patients without OD, and the lower IL-6 levels is related to milder course of the disease. With the effect of low cytokine storm and IL-6 level, it may be said that anosmic cases have a milder disease in COVID-19.

Olfactory Cleft Measurements and COVID-19-Related Anosmia.

OBJECTIVE: This study aimed to investigate the differences in olfactory cleft (OC) morphology in coronavirus disease 2019 (COVID-19) anosmia compared to control subjects and postviral anosmia related to infection other than severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). STUDY DESIGN: Prospective. SETTING: This study comprises 91 cases, including 24 cases with anosmia due to SARS-CoV-2, 38 patients with olfactory dysfunction (OD) due to viral infection other than SARS-CoV-2, and a control group of 29 normosmic cases. METHODS: All cases had paranasal sinus computed tomography (CT), and cases with OD had magnetic resonance imaging (MRI) dedicated to the olfactory nerve. The OC width and volumes were measured on CT, and T2-weighted signal intensity (SI), olfactory bulb volumes, and olfactory sulcus depths were assessed on MRI. RESULTS: This study showed 3 major findings: the right and left OC widths were significantly wider in anosmic patients due to SARS-CoV-2 (group 1) or OD due to non-SARS-CoV-2 viral infection (group 2) when compared to healthy controls. OC volumes were significantly higher in group 1 or 2 than in healthy controls, and T2 SI of OC area was higher in groups 1 and 2 than in healthy controls. There was no significant difference in olfactory bulb volumes and olfactory sulcus depths on MRI among groups 1 and 2. CONCLUSION: In this study, patients with COVID-19 anosmia had higher OC widths and volumes compared to control subjects. In addition, there was higher T2 SI of the olfactory bulb in COVID-19 anosmia compared to control subjects, suggesting underlying inflammatory changes. There was a significant negative correlation between these morphological findings and threshold discrimination identification scores. LEVEL OF EVIDENCE: Level 4.

Presurgical detection of brain invasion status in meningiomas based on first-order histogram based texture analysis of contrast enhanced imaging.

OBJECTIVE: Invasion of brain parenchyma by meningioma can be a critical factor in surgical planning. The aim of this study was to determine the diagnostic utility of first-order texture parameters derived from both whole tumor and single largest slice of T1-contrast enhanced (T1-CE) images in differentiating meningiomas with and without brain invasion based on histopathology demonstration. METHODS: T1-CE images of a total of 56 cases of grade II meningiomas with brain invasion (BI) and 52 meningiomas (37 grade I and 15 grade II) with no brain invasion (NBI) were analyzed. Filtration-based first-order histogram derived texture parameters were calculated both for whole tumor volume and largest axial cross-section. Random forest models were constructed both for whole tumor volume and largest axial cross-section individually and were assessed using a 5-fold cross validation with 100 repeats. RESULTS: In detection of brain invasion, random forest model based on whole tumor segmentation had an AUC of 0.988 (95 % CI 0.976-1.00) with a cross validated value of 0.74 (95 % CI 0.45-0.96). For differentiation of grade I meningiomas from grade II meningiomas with brain invasion, the AUC was 0.999 (95 % CI 0.995-1.00) and 0.81 (95 % CI 0.61-0.99) in the training and validation cohorts, respectively. Similarly, when using only the single largest slice, the cross-validated AUC to distinguish BI versus NBI and BI versus grade I meningiomas was 0.67 (95 % CI 0.47, 0.92 and 0.78 (95 % CI 0.52, 0.95) respectively. CONCLUSION: Radiomics based feature analysis applied on routine MRI post-contrast images may be helpful to predict presence of brain invasion in meningioma, possibly with better performance when comparing BI versus grade I meningiomas.

Prognostic value of pretreatment tumor-to-blood standardized uptake ratio (SUR) in rectal cancer.

OBJECTIVES: The prognostic value of SUV on pretreatment F-18 FDG PET/CT imaging in patients with rectal cancer is a matter of debate. SUR is of prognostic value for survival in different cancers. In this study, we aimed to examine the potential prognostic value of SUR and other parameters in pretreatment F-18 FDG PET/CT for non-metastatic rectal cancer. METHODS: One hundred four non-metastatic rectal cancer patients who underwent pretreatment PET/CT between March 2012 and January 2018 were included in the study. Firstly, SUVmax, SUVmean, MTV, and TLG were calculated semi-automatically at the workstation. SUR was calculated as the ratio of tumor SUVmax to thoracic aorta blood SUVmean. Univariate Cox regression and Kaplan-Meier analysis were used to evaluate overall survival (OS), progression free survival (PFS), and local recurrence (LR). Then, multivariate Cox regression analysis, which included the parameters that were significant in the univariate analysis, was performed. RESULTS: Multivariate Cox regression analysis revealed that SUR was a prognostic factor for PFS. Age and T stage were prognostic factors for both OS and PFS. MTV was found to be independent risk factors for OS. CONCLUSIONS: In our study, SUR was the only F-18 FDG PET/CT parameter found to be significant for PFS. The development of new parameters can increase the prognostic value of F-18 FDG PET/CT.

Temporal Evolution of Imaging Findings in Ossified Cephalohematoma.

BACKGROUND: Cephalohematoma is collection of blood between skull and periosteum that is confined by cranial sutures. Cephalohematomas usually resorb spontaneously within the first month of life; however, if it fails to resolve, ossified cephalohematoma may form. METHODS: Clinical archiving system and picture archiving and communication system were retrospectively reviewed for cases of birth-related cephalohematoma. Cases of ossified cephalohematomas identified on imaging were retrieved from this subset of patients. Cross-sectional imaging findings in patients with ossified cephalohematomas were evaluated for location, size of the hematoma, and contours of the inner lamella. RESULTS: Out of 115 cases of cephalohematoma, 7 cases had imaging findings consistent with ossified cephalohematoma. All ossified cephalohematomas were located parietally, with size ranging between 18 and 55 mm and the thickness of the outer rim of calcification ranging between 1.5 and 4.8 mm. The contour of inner lamella in relation to the surrounding normal cranial vault was normal in 5 cases, and inner lamella was depressed in 2 cases.Three patients had follow-up imaging available for demonstration of changes in ossified cephalohematoma. The first case was an 11 day-old boy with a cephalohematoma with no signs of calcification at the time of initial imaging. Follow-up at 2 months of age showed partial regression of hematoma cavity with marked calcification at the hematoma walls. The second case was a 3 month-old boy with ossified cephalohematoma at initial imaging. Follow-up imaging at 7 months of age showed almost total regression of hematoma cavity, and approximation of inner and outer lamella with increased thickness of the cranial vault. The third case was a 1 month-old boy with ossified cephalohematoma at initial imaging that totally resolved without residual increased bone thickness at 21-month follow-up. CONCLUSION: These 3 cases demonstrate the variability in temporal changes that may occur in ossified cephalohematomas.

Unique imaging appearance of neurosarcoidosis as a solitary cystic mass with mural enhancement.

BACKGROUND: Sarcoidosis is an idiopathic, granulomatous, and multi-system inflammatory disorder that can also involve the central nervous system in the form of meningeal, parenchymal, or cranial nerve involvement. Imaging findings can be non-specific and may overlap with other inflammatory, infectious and neoplastic processes, and posing diagnostic challenges. Parenchymal involvement in neurosarcoidosis (NS) predominantly manifests as either non-enhancing white matter lesions or as enhancing parenchymal granulomas. Granulomas usually manifest as multiple solid lesions with nodular enhancement. CASE DESCRIPTION: A 72-year-old man presented with right-eye visual field changes with the non-contrast head computed tomography showing a large cystic lesion in the left frontoparietal lobe. Subsequent contrast-enhanced magnetic resonance imaging study revealed a large cystic mass with irregular rim enhancement and mural nodule concerning for glial neoplasm. Cyst decompression with biopsy and histopathological analysis revealed gliosis and prominent perivascular granulomatous inflammation with mixed picture of CD4 and CD8-positive cells suggestive of sarcoidosis. Further subsequent work-up showed mediastinal and cervical lymphadenopathy which on biopsy showed non-necrotizing granulomatous inflammation, consistent with sarcoidosis. CONCLUSION: Herein, we report unique imaging findings of a NS case manifesting as a solitary cystic intraparenchymal lesion with an enhancing nodular component, mimicking primary intra-cranial tumor. This appearance is highly atypical and rarely been reported earlier.

Post-Traumatic Occipital Intradiploic Encephalocele.

BACKGROUND: Brain parenchyma herniation through a disrupted inner table into an enlarged diploic cavity with an intact outer table is described as intradiploic encephalocele. Intradiploic encephaloceles share common morphologic characteristics with expanding skull fractures and intradiploic arachnoid cysts. Herein, we describe a case of traumatic occipital intradiploic encephalocele. CASE DESCRIPTION: Cranial computed tomography of an 11-year-old boy revealed erosion of the inner table of the left side of occipital bone and expansion of the cranial diploë by a soft-tissue density with a gyral pattern. His medical history was positive for head trauma at the age of 3 years to the same region. Magnetic resonance imaging showed herniation of left occipital parenchyma with cystic encephalomalacic changes into the diploë. CONCLUSIONS: Intradiploic encephaloceles have different features compared with the classic encephalocele and can be considered as a variant of expanding skull fracture and intradiploic arachnoid cyst.

Cerebral Hydatid Cyst with Intraventricular Extension: A Case Report.

Intracranial hydatid cyst is a rare entity, comprising about 2-3% of all hydatid cysts. Similarly, intracranial hydatid cysts account for 1-2% of all intracranial lesions. Clinical symptoms are generally nonspecific and patients usually present with symptoms of increased intracranial pressure. Cerebral hydatid cysts can be either primary or secondary to systemic hydatid disease. Primary cerebral hydatid cysts are usually solitary, unilocular with an intraparenchymal location. Intraventricular extension of hydatid cysts account for a limited percentage of all cerebral hydatid cysts with limited number of cases reported. Herein, we present the imaging and surgical findings of a primary cerebral hydatid cyst that is located in frontal lobe parenchyma with partial extension into the ventricular system.

Single-stage planning for total cure of grade III-V brain arteriovenous malformations by embolization alone or in combination with microsurgical resection.

PURPOSE: There are no established guidelines for treatment of Spetzler-Martin grade III-V brain arteriovenous malformations (bAVMs). The purpose of this study is to report our institutional experience in total obliteration/eradication of grade III-V bAVMs by single-stage planning of embolization combined with microsurgical resection when necessary. METHODS: All patients harboring Spetzler-Martin (S-M) grade III-V bAVMs treated with single-stage planning between January 2006 and January 2018 were retrospectively reviewed. This treatment paradigm is applicable only to surgically accessible bAVMs and does not include deep-seated bAVMs. Indications for treatment, clinical presentation, imaging characteristics, and treatment outcomes were analyzed. Outcomes were assessed based on modified Rankin Scale. RESULTS: A total of 31 patients were identified. Seventeen patients (54.8%) presented with hemorrhage, 10 (32.3%) with seizures, 3 (9.7%) with headaches, and 1 (3.2%) with progressive neurological deficit. Based on S-M grading system, 25 patients (80.6%) harbored grade III bAVM, 5 patients had grade IV bAVMs (16.1%), and 1 patient (3.2%) had a grade V bAVM. There were no treatment-related complications in 24/31 (77.4%) patients. Of the total of seven patients with complications, four patients had clinical deterioration. The long-term (> 6-month), non-disabling morbidity (mRS ≤ 2) rate was 6.5%. The long-term, disabling morbidity rate was 3.2% with a mortality of 3.2%. Complete angiographic obliteration was achieved in 30/31 (96.8%) patients. CONCLUSION: Single-stage treatment strategy can be considered as an alternative to multistage embolization prior to surgery in grade III-V bAVMs. In this study, a high rate of total obliteration with relatively low rates of permanent morbidity and mortality was achieved.

Combined Spinal Arteriovenous Malformation and Spinal Dysraphism.

BACKGROUND: Spinal vascular malformations as a group are rare, and coexistence of a spinal arteriovenous malformation (AVM) in or around the spinal dysraphism is extremely rare. We report 2 cases of combined spinal dysraphism and vascular malformations of the spinal cord. CASE DESCRIPTION: The first case was an AVM located in a filum terminale lipoma fed by the artery of the filum terminale. This case was managed by multiple endovascular embolizations followed by surgery. The second case was an AVM located in a lumbar lipomyelocele managed by endovascular embolization. These cases illustrate the imaging findings of a rare entity and present the diagnostic and therapeutic challenges. CONCLUSIONS: Endovascular embolization combined with surgical resection is the most commonly used treatment for spinal dysraphism with spinal cord AVM. Careful analysis of spinal angiography is necessary owing to the distorted vascular and surgical anatomy of the region affected by spinal dysraphism.

Bladder cancer in an inguinal vesical hernia.

A 60-year-old male patient presented with intermittent right-sided scrotal swelling for the last 4 months. On ultrasonography, a fluid-filled cavity extending through the right inguinal canal into the scrotum was noted with inferior displacement of the right testis. Multiple papillary hyperechoic lesions with internal vascularity on Doppler ultrasound were protruding into the fluid-filled cavity. Computed tomography showed herniation of the bladder through the right inguinal canal into the scrotum with mural components in the herniated segment. Hernioplasty followed by transurethral tumor resection showed urothelial carcinoma with invasion into the muscular layer. Vesical herniation through the inguinal canal is uncommon. Additionally, the presence of bladder carcinoma within a herniated portion of the bladder is exceedingly rare.

Amyloid Goiter: A Diagnosis to Consider in Diffuse Fatty Infiltration of the Thyroid.

An amyloid goiter is the presence of amyloid protein in the thyroid in sufficient amounts to produce enlargement of the gland, accompanied by fat deposition of varying extents. It can be seen in long-standing inflammatory disorders such as familial Mediterranean fever. Imaging findings depend on the amount of fat and amyloid deposition; however, the main imaging finding is diffuse fatty infiltration of the thyroid. Herein, the multimodality imaging features in 3 cases of amyloid goiters secondary to familial Mediterranean fever are presented.

Acoustic radiation force impulse (ARFI) elastography in the evaluation of renal parenchymal stiffness in patients with ureteropelvic junction obstruction.

PURPOSE: To investigate the role of acoustic radiation force impulse (ARFI) elastography in the detection of renal parenchymal damage in kidneys with and without ureteropelvic junction obstruction (UPJO). METHODS: Twenty-five pediatric patients with a diagnosis of UPJO who underwent surgery and 15 pediatric patients with conservatively managed UPJO were prospectively evaluated with ARFI elastography. Sixteen healthy volunteers constituted the control group. Shear wave velocity (SWV) measurements in the upper, mid, and lower poles of the affected kidney were performed. SWV values of kidneys based on presence of UPJO and hydronephrosis grade were compared. The correlation of SWV values with residual renal function obtained from diethylenetriaminepentaacetic acid or mercaptoacetyltriglycine-3 renal scan was evaluated. RESULTS: Significantly, higher SWV values were found in control kidneys compared to kidneys affected by UPJO. The median SWVs were 2.82 (2.51-3.07) m/s for the control kidneys and 2.36 (2.09-2.53) m/s for the kidneys in the UPJO group (p < 0.001). When UPJO patients were grouped according to the grade of hydronephrosis, grade 0 hydronephrotic kidneys [2.35 (2.11-2.50) m/s] and grade 3-4 hydronephrotic kidneys [1.86 (1.96-2.25) m/s] had significantly lower SWV values compared to grade 1-2 hydronephrotic kidneys [2.62 (2.37-2.90) m/s] (p < 0.05). CONCLUSIONS: ARFI as a noninvasive, radiation-free procedure for evaluating parenchymal stiffness may prove useful in the diagnostic work-up and follow-up of children with UPJO-induced renal disease.

Evaluation of anterior mediastinal solid tumors by CT perfusion: a preliminary study.

PURPOSE: We aimed to assess the role of computed tomography (CT) perfusion in differentiation of thymoma from thymic hyperplasia, lymphoma, thymic carcinoma, and lung cancer invading anterior mediastinum. METHODS: In this study, 25 patients with an anterior mediastinal lesion underwent CT perfusion imaging from January 2015 to February 2016. Diagnoses included thymoma (n=7), thymic hyperplasia (n=8), lymphoma (n=4), thymic carcinoma (n=3), and invasive lung cancer (n=3). Lymphoma, thymic carcinoma, and lung cancer were grouped as malignant tumors for statistical analysis. Values for blood flow, blood volume, and permeability surface were measured in CT perfusion. RESULTS: Blood flow and blood volume values were higher in thymoma in comparison to thymic hyperplasia; however, the difference was not statistically significant. Blood volume values were significantly higher in thymoma (mean, 11.4 mL/100 mL; range, 5.2-20.2 mL/100 mL) compared with lymphoma (mean, 5.3 mL/100 mL; range, 2.5-7.2 mL/100 mL) (P = 0.023). Blood flow and blood volume values were significantly higher in thymoma compared with non-thymoma malignant tumors (P = 0.025). CONCLUSION: CT perfusion is helpful in differentiating thymoma from non-thymoma malignancies including lymphoma, thymic carcinoma, and invasive lung cancer involving the anterior mediastinum.