Comparative Analysis of FSE T2 Weighted, Chemical Shift and Dynamic Contrast-Enhanced MR Imaging in the Characterization of Adrenal Masses Based on Qualitative and Quantitative Parameters.

Objectives: The purpose of our study was to investigate the role of different magnetic resonance imaging (MRI) parameters in the characterization of adrenal masses. Methods: A total of 150 patients who presented with 186 adrenal tumors were retrospectively evaluated in this study. Final patient cohort consisted of 17 pheochromocytomas, 3 adrenocortical carcinomas, 24 metastases, 31 lipid-poor adenomas and 111 lipid-rich adenomas. We carried out a visual assessment on FSE (Fast spin echo)T2 weighted images and also calculated T2 signal intensity ratio of all adrenal masses and also performed a qualitative assessment on chemical shift imaging (CSI) together with quantitative calculation using Adrenal to spleen signal intensity (si) ratio and Adrenal si index formulas. On dynamic contrast-enhanced sequences, visual assessment based on enhancement patterns on late-arterial phase images was performed and also mean signal intensity measurements were carried out. All examinations were interpreted by two abdominal radiologists in consensus who were blinded to the clinical and pathological findings. Statistical analysis was performed. Results: On FSE T2 weighted imaging, isointense to liver and slightly hyperintense than liver was found higher in benign cases, however, in malignant cases moderately and strikingly hyperintense than liver was higher than in benign cases (p=0.001, p<0.01). There was a statistically significant difference between the T2 signal intensity ratio values of adrenal tumor groups (p=0.001, p<0.01). In lipid-rich and lipid-poor adenoma groups, T2 signal intensity ratio values was significantly lower than in pheochromocytoma and metastasis cases. In malignant group, T2 signal intensity ratio values were found statistically significantly higher than in the benign group (p=0.001, p<0.01). There was a statistically significant difference between CSI visual assessment of adrenal tumor groups (p=0.001, p<0.01). Although moderate and significant signal intensity loss was usually detected in lipid-rich adenoma group, never detected in other tumor groups. There was also a statistically significant difference between benign and malignant adrenal tumor groups (p=0.001, p<0.01). In the malignant group, Adrenal to spleen si ratio values were found significantly higher whereas, Adrenal si index values were significantly lower compared to benign tumors (p=0.001, p<0.01). Based on malignancy, there was a statistically significant difference between adrenal tumor groups (p=0.001, p<0.01). Although capillary blush and homogenous type enhancement were more common in benign cases than in malignant ones, peripheral-patchy and strikingly capillary blush type enhancement was more frequent in malignant tumors. Based on malignancy, mean arterial signal intensity values of malignant tumors were statistically higher than benign tumors (p=0.001; p<0.01). Conclusion: Dynamic contrast-enhanced MRI protocol including CSI aids in the characterization of indeterminate adrenal masses. Herein, the combined use of qualitative and quantitative parameters enables more tumors to be recognized that otherwise would be indeterminate.

Is There a Relationship Between Epicardial Adipose Tissue, Inflammatory Markers, and the Severity of COVID-19 Pneumonia?

Objectives: Epicardial adipose tissue (EAT) is a type of visceral adipose tissue with pro-inflammatory properties. We sought to examine the relationship between the EAT volume and attenuation measured on non-contrast chest computed tomography (CT), inflammation markers, and the severity of COVID-19 pneumonia. Methods: One hundred and twenty-five patients who are over 18 years old who applied to our hospital and were found to have COVID-19 polymerase chain reaction (+) on nasopharyngeal swab sample and COVID-19 pneumonia on chest CT were included in the study. At admission, C-reactive protein (CRP), procalcitonin, fibrinogen, leukocytes, neutrophil-lymphocyte ratio, platelet-lymphocyte ratio, lactate dehydrogenase (LDH), ferritin, and d-dimer were evaluated. EAT volume and attenuation were measured on chest CT. Patients who were hospitalized and discharged from the ward were categorized as Group 1, whereas patients who required intensive care admission and/or died were classified as Group 2. The primary endpoint of our study was defined as death, hospitalization in the intensive care unit, and discharge. The relationship between disease severity and EAT and other inflammatory markers was investigated. Results: One hundred and six individuals were in Group 1 and 19 patients were in Group 2. Of the 125 individuals, 46 were women and 79 were men. The mean age was 58.5±15.9 years. Group 2 patients were older. Regarding measurements of the EAT volume and attenuation; there was no statistically significant difference between the groups determined. The patients in Group 2 had statistically substantially higher values for urea, creatinine, LDH, d-dimer, troponin T, procalcitonin, CRP, and neutrophil/lymphocyte ratio in their laboratory tests. When compared to patients in Group 1, patients in Group 2 had statistically significantly lower albumin values (p<0.001). In obese patients, EAT volume was statistically significantly higher and EAT attenuation was found to be lower. Conclusion: In our study, no relationship was found between critical COVID-19 disease and EAT volume and attenuation, which is an indicator of EAT inflammation. Inflammatory markers from routine laboratory tests can be used to predict critical COVID-19 disease. No relationship was found between obesity and critical COVID-19 disease.

Predictive role of magnetic resonance imaging in the distinction of isocitrate dehydrogenase (IDH) mutant grade 4 astrocytomas versus glioblastomas.

BACKGROUND: Isocitrate dehydrogenase (IDH) mutation status is a crucial prognostic factor in high-grade glial tumors. PURPOSE: To investigate whether magnetic resonance imaging (MRI) features can display a diagnostic performance in the determination of IDH mutation in high-grade gliomas. MATERIAL AND METHODS: A total of 170 patients including 24 IDH mutant grade 4 astrocytomas and 146 glioblastomas (GBM) were retrospectively examined via contrast-enhanced (CE) MRI before surgery. Immunohistochemistry and genomic sequence analyses were performed on specimen materials for the determination of IDH mutational status. Certain morphological and diffusion-weighted imaging (DWI) parameters were utilized to see if they could play a role to be non-invasive potential imaging predictors in the discrimination of IDH mutant versus wild-type (WT) high-grade gliomas. RESULTS: On histopathological examination, IDH mutation was detected in 24 patients with high-grade glioma and 146 of the patients were found to be WT. Certain morphological criteria of tumor location and involvement, tumor margins, visual detection of diffusion restriction on DWI, and quantitative apparent diffusion coefficient (ADC) parameters consisting of ADCmean, ADCmin, and ADCr could be used as imaging predictors in the discrimination of high-grade IDH mutant versus WT tumors. CONCLUSION: Certain MRI morphologic features and visual detection of diffusion restriction on DWI and quantitative ADC parameters consisting of ADCmean, ADCmin, and ADCr can be considered non-invasive, significant independent imaging predictors in the discrimination and can obviate invasive procedures for histopathological diagnosis.

Detection of COVID-19 and its pulmonary stage using Bayesian hyperparameter optimization and deep feature selection methods.

Since the first case of COVID-19 was reported in December 2019, many studies have been carried out on artificial intelligence for the rapid diagnosis of the disease to support health services. Therefore, in this study, we present a powerful approach to detect COVID-19 and COVID-19 findings from computed tomography images using pre-trained models using two different datasets. COVID-19, influenza A (H1N1) pneumonia, bacterial pneumonia and healthy lung image classes were used in the first dataset. Consolidation, crazy-paving pattern, ground-glass opacity, ground-glass opacity and consolidation, ground-glass opacity and nodule classes were used in the second dataset. The study consists of four steps. In the first two steps, distinctive features were extracted from the final layers of the pre-trained ShuffleNet, GoogLeNet and MobileNetV2 models trained with the datasets. In the next steps, the most relevant features were selected from the models using the Sine-Cosine optimization algorithm. Then, the hyperparameters of the Support Vector Machines were optimized with the Bayesian optimization algorithm and used to reclassify the feature subset that achieved the highest accuracy in the third step. The overall accuracy obtained for the first and second datasets is 99.46% and 99.82%, respectively. Finally, the performance of the results visualized with Occlusion Sensitivity Maps was compared with Gradient-weighted class activation mapping. The approach proposed in this paper outperformed other methods in detecting COVID-19 from multiclass viral pneumonia. Moreover, detecting the stages of COVID-19 in the lungs was an innovative and successful approach.

CT and MR Imaging Findings in Methanol Intoxication Manifesting with BI Lateral Severe Basal Ganglia and Cerebral Involvement.

Our case report describes a 54-year-old man who was admitted to our hospital complaining of visual impairment with gastrointestinal and neurological symptoms. Initial computed tomography examination showed bilateral symmetric putaminal and cerebral white matter hypodensities. Evaluation of the following magnetic resonance imaging, restricted diffusion in these corresponding areas were found to be compatible with cytotoxic edema. Teaching Point: Diffusion-weighted imaging (DWI) plays a crucial role in the diagnosis of acute methanol intoxication.

Detection of COVID-19 findings by the local interpretable model-agnostic explanations method of types-based activations extracted from CNNs.

Covid-19 is a disease that affects the upper and lower respiratory tract and has fatal consequences in individuals. Early diagnosis of COVID-19 disease is important. Datasets used in this study were collected from hospitals in Istanbul. The first dataset consists of COVID-19, viral pneumonia, and bacterial pneumonia types. The second dataset consists of the following findings of COVID-19: ground glass opacity, ground glass opacity, and nodule, crazy paving pattern, consolidation, consolidation, and ground glass. The approach suggested in this paper is based on artificial intelligence. The proposed approach consists of three steps. As a first step, preprocessing was applied and, in this step, the Fourier Transform and Gradient-weighted Class Activation Mapping methods were applied to the input images together. In the second step, type-based activation sets were created with three different ResNet models before the Softmax method. In the third step, the best type-based activations were selected among the CNN models using the local interpretable model-agnostic explanations method and re-classified with the Softmax method. An overall accuracy success of 99.15% was achieved with the proposed approach in the dataset containing three types of image sets. In the dataset consisting of COVID-19 findings, an overall accuracy success of 99.62% was achieved with the recommended approach.

Comparison of cortico-medullary phase contrast-enhanced MDCT and T2-weighted MR imaging in the histological subtype differentiation of renal cell carcinoma: radiology-pathology correlation.

PURPOSE: Renal cell carcinoma (RCC) subtype differentiation is of crucial importance in the management and prognosis of these patients. In this study, we investigated the usefulness of unenhanced and cortico-medullary phase contrast-enhanced multidetector-row computed tomography (MDCT) and T2-weighted fast spin-echo (FSE) magnetic resonance imaging (MRI) modalities in the discrimination of the 3 main subtype RCC patients in correlation with their histopathological findings. MATERIAL AND METHODS: A total of 80 pathologically proven RCC patients who had undergone either partial or total nephrectomy were retrospectively investigated in this study. Their histological subtypes were 54 clear cell renal cell carcinoma (ccRCC), 15 papillary renal cell carcinoma (pRCC), and 11 chromophobe renal cell carcinoma (cRCC), based on pathological evaluation. There were 62 male (77.5%) and 18 female (22.5%) patients. Among the 54 ccRCC patients, 29 patients had both non-contrast and cortico-medullary phase CT, 1 had only non-contrast CT, 5 only had cortico-medullary phase CT, and 38 had MRI examination. In the pRCC group, 10 patients had both non-contrast and cortico-medullary phase CT, 1 had only non-contrast CT, 1 had only cortico-medullary phase CT, and 12 had MRI. Finally, in the remaining 11 cRCC patients, 9 had both non-contrast and cortico-medullary phase CT, and only 5 had MRI. We calculated both tumour attenuation values as HU (Hounsfield units) on unenhanced and cortico-medullary phase MDCT images and also tumour mean signal intensity values on FSE T2-weighted MRI images by using the region of interest (ROI) including normal renal cortex measurements. Besides quantitative evaluation, we also performed qualitative visual assessment of tumours on contrast-enhanced MDCT and FSE T2-weighted MRI. RESULTS: There was no statistically significant difference among the attenuation values of the 3 tumour subtypes on pre-contrast CT images. ccRCC demonstrated a prominent degree of contrast enhancement compared to the chromophobe and papillary ones on cortico-medullary phase MDCT. We found no statistically significant difference between chromophobe and papillary subtypes, although chromophobe tumours showed slightly higher attenuation values compared to papillary ones. ccRCCs usually demonstrated a heterogenous contrast enhancement on cortico-medullary phase CT images, while the papillary subtype usually had a homogenous appearance on visual assessment. On FSE T2-weighted MR images, the signal intensity values of ccRCC patients were found to be significantly higher than both chromophobe and papillary subtypes. Although cRCC patients had a prominently lower T2 signal intensity than clear cell subtype, there was no statistically significant signal intensity difference between chromophobe and papillary subtypes. Regarding visual assessment, papillary subtype tumours showed a mostly homogenous appearance on T2-weighted images and a statistically significant difference was present. On the other hand, there was no significant difference of visual assessment of the clear cell and chromophobe subtypes. CONCLUSIONS: The measurement of the attenuation values on cortico-medullary phase MDCT and the mean signal intensity values on FSE T2-weighted MRI can provide useful information in the differentiation of RCC main subtypes. Also, visual assessment of tumours on both modalities can contribute to this issue by providing additional imaging properties.

Recurrent Solitary Fibrous Tumor in Intradural Extramedullary Space: Case Report and Review of the Literature.

Solitary fibrous tumor/hemangiopericytoma (SFT/HPC) is a rare neoplasm arising from spindle cells and most commonly arising from pleura. Spinal SFT/HPC is a rare entity; hence, it is not on the top of the differential diagnosis list when a clinician faces a spinal lesion. In the review of the literature, there exist less than 50 case reports of intradural extramedullary SFT/HPC. Here, we present a 54-year-old female patient who underwent subtotal surgical excision of an intradural extramedullary spinal mass pathologically reported to be SFT/HPC and had symptomatic recurrence in the 3rd year of follow-up. Surgical intervention was unachievable and the patient was given 45 Gy to the surgical cavity followed by a 5.4 Gy boost to visible tumor with external radiotherapy. Patient reported significant relief of her symptoms. We aim to contribute to the formation of a treatment algorithm for this rare entity.

Tumor grade estimation of clear cell and papillary renal cell carcinomas using contrast-enhanced MDCT and FSE T2 weighted MR imaging: radiology-pathology correlation.

BACKGROUND: Discrimination of low grade (grade 1-2) renal tumors from high grade (grade 3-4) ones carries crucial importance in terms of the management of these patients and also in the decision-making of appropriate treatment strategies. Our aim was to investigate whether contrast-enhanced multidetector computed tomography (MDCT) and T2 weighted fast spin echo (FSE) magnetic resonance imaging (MRI) could play a specific role in the discrimination of low grade versus high grade tumors in clear cell renal cell carcinoma (ccRCC) and papillary renal cell carcinoma (pRCC) patients. METHODS: In this study, we retrospectively evaluated 66 RCC patients based on histopathologic findings who had underwent either partial or total nephrectomies. Our cohort consisted of 52 ccRCC and 14 pRCC patients, of whom 50 were male (%76) and 16 were female (%24). Among the 52 ccRCC patients, 18 had both cortico-medullary phase contrast-enhanced CT and MRI, 15 had only cortico-medullary phase CT and 19 had only MRI examination. In the pRCC group, 8 patients had both cortico-medullary phase contrast-enhanced CT and MRI, 3 had only cortico-medullary phase CT and 3 had only MRI. We both calculated mean tumor attenuation values on cortico-medullary phase MDCT images as HU (hounsfield unit) and also tumor mean signal intensity values on FSE T2 weighted MR images, using both region of interest and whole lesion measurements including normal renal cortex. The obtained values were compared with the grading results of the ccRCC and pRCC tumors according to the WHO/International Society of Urological Pathology grading system. RESULTS: A significant positive correlation was found between the mean attenuation values of both tumor subtypes on cortico-medullary phase contrast-enhanced CT and their grades (p < 0.001). High grade tumors exhibited higher mean attenuation values (74.3 ± 22.3 HU) than the low grade tumors (55.2 ± 23.7 HU) in both subtypes. However, a statistically significant correlation was not found between the mean signal intensity values of the two tumor subtypes on FSE T2 weighted MR images and their grades (p > 0.05). Low grade tumors had a mean signal intensity value of 408.9 ± 44.6, while high grade tumors showed a value of 382.1 ± 44.2. The analysis of the ccRCC group patients, yielded a statistically significant correlation between the mean signal intensity values on T2 weighted images and tumor grading (p < 0.001). Low grade (grade 1-2) ccRCC patients exhibited higher mean signal intensity values (475.7 ± 51.3), as compared to those of high grade (grade 3-4) (418.5 ± 45.7) tumors. On the other hand, analysis of the pRCC group patients revealed that there was a significant correlation between the mean attenuation values of tumors on cortico-medullary phase contrast-enhanced CT and their grades (p < 0.001). High grade papillary subtype tumors (54.2 ± 25.2) showed higher mean attenuation values than the low grade (35.5 ± 18.8) ones. CONCLUSIONS: Contrast-enhanced MDCT and T2 weighted FSE MRI can play a considerable role in the discrimination of low grade versus high grade tumors of both subtype RCC patients. Thus, these non-invasive evaluation techniques may have positive impact on the determination of the management and treatment strategies of these patients.

Multiple cranial nerve schwannomas and meningiomas as a hallmark sign of neurofibromatosis type 2 in a child.

Halefoglu AM. Multiple cranial nerve schwannomas and meningiomas as a hallmark sign of neurofibromatosis type 2 in a child. Turk J Pediatr 2018; 60: 107-110. Neurofibromatosis type 2 is a rarely encountered autosomal dominant disorder manifesting with typical radiological findings. These patients have a predilection for development of benign tumors in the central nervous system. Although the presenting symptom is most commonly hearing loss due to acoustic schwannomas, symptoms emanating from other cranial tumors are not uncommon. Herein, we described a 16-year-old male patient presented with multiple meningiomas and cranial nerve schwannomas revealed by magnetic resonance imaging. He fulfilled the diagnostic criteria of neurofibromatosis type 2 and underwent treatment. We emphasized the role of radiology in the early diagnosis of this inherited disorder in order to provide a better prognosis.

Susceptibility weighted imaging: Clinical applications and future directions.

Susceptibility weighted imaging (SWI) is a recently developed magnetic resonance imaging (MRI) technique that is increasingly being used to narrow the differential diagnosis of many neurologic disorders. It exploits the magnetic susceptibility differences of various compounds including deoxygenated blood, blood products, iron and calcium, thus enabling a new source of contrast in MR. In this review, we illustrate its basic clinical applications in neuroimaging. SWI is based on a fully velocity-compensated, high-resolution, three dimensional gradient-echo sequence using magnitude and phase images either separately or in combination with each other, in order to characterize brain tissue. SWI is particularly useful in the setting of trauma and acute neurologic presentations suggestive of stroke, but can also characterize occult low-flow vascular malformations, cerebral microbleeds, intracranial calcifications, neurodegenerative diseases and brain tumors. Furthermore, advanced MRI post-processing technique with quantitative susceptibility mapping, enables detailed anatomical differentiation based on quantification of brain iron from SWI raw data.

A Rare Tumor in Childhood Desmoplastic Infantile Astrocytoma: Two Case Reports.

Desmoplastic infantile astrocytomas (DIAs), are rare supratentorial tumors, usually observed in the first 24 months of life. Despite their aggressive appearance, they tend to follow a favorable clinical course. Total or near total resection of tumor is usually the treatment option. Desmoplastic Infantile Ganglioglioma (DIG) and DIA are WHO grade I tumors that have similar clinical and morphological findings. The only criterion in differential diagnosis is the neural component of DIG. These tumors both have dense fibroblastic stroma and positive staining with glial fibrillar acidic protein (GFAP) and CD34. A rare case of desmoplastic infantile astrocytoma presenting with right side partial seizures presented in a 1-year-old child. A rare case of desmoplastic infantile astrocytoma presenting with focal onset generalized seizures presented in a 1-year-old child. Despite their radiological and histological properties, these tumors have a benign course. After 3-year follow-up for the first case and 1-year follow-up for the second case, there was no recurrence.

Utility of diffusion-weighted MRI in the diagnosis of bladder carcinoma.

BACKGROUND: The purposes of our study were to investigate the feasibility of diffusion-weighted imaging in the detection of malignant bladder tumors, with comparison to the high-resolution thin-section fast spin-echo (FSE) T2-weighted MRI, and also to compare the apparent diffusion coefficient (ADC) values of the bladder tumors with the surrounding structures. MATERIAL AND METHODS: Fifty-three consecutive patients consisting of 44 males and 9 females who presented with a bladder mass were prospectively enrolled in this study. Mean age was 62.53 ± 12.03 (age range, 33-86 years). These patients were evaluated by high-resolution thin-section FSE T2-weighted and diffusion-weighted MRI for the detection of bladder masses. Following MRI, within 2 weeks, all patients were subjected to either surgery or cystoscopic biopsy, and the obtained histopathological proofs were used as the reference standard. Furthermore, ADC values of the bladder tumors, urine, the normal bladder wall, the central and peripheral zones of the prostate, the seminal vesicule, and the uterus outer myometrium were also calculated. ADC values of the bladder carcinomas and the related surrounding structures were compared as to whether a statistically significant difference was present or not. RESULTS: In a total of 47 patients, consisting of 39 males and 8 females, bladder carcinomas were clearly shown as having conspicuous high and intermediate signal intensity masses, relative to the surrounding structures on diffusion-weighted and T2-weighted images, respectively. An 89% sensitivity and a 100% positive predictive value were obtained for both FSE T2-weighted and diffusion-weighted MRI in the diagnosis of bladder carcinoma. Mean ADC values and standard deviations of the bladder tumors and the surrounding structures were as follows: bladder carcinomas (n=47): 1.28 ± 0.31, normal bladder wall (n=47): 1.98 ± 0.41, urine (n=47): 3.12 ± 0.24, seminal vesicle (n=39): 1.82 ± 0.33, peripheral zone of prostate (n=39): 1.80 ± 0.29, central zone of prostate (n=39): 1.55 ± 0.33, and uterus outer myometrium (n=8): 1.53 ± 0.19. It can be clearly seen that the mean ADC values of the bladder carcinomas were significantly lower than the surrounding structures (P<.05). CONCLUSION: High-resolution thin-section FSE T2 and diffusion-weighted MRI show high diagnostic performance and are comparable in the detection of bladder tumors. Diffusion-weighted MRI provides high quality images of the malignant bladder tumors against a suppressed background signal. Diffusion-weighted MRI using ADC measurements may be useful in the evaluation of tumor invasion to the adjacent organs.

Accuracy of thin-section magnetic resonance imaging with a pelvic phased-array coil in the local staging of rectal cancer.

OBJECTIVE: The goal of this study was to determine the accuracy of thin-section magnetic resonance imaging (MRI) using a pelvic phased-array coil for preoperative local staging of rectal carcinoma. METHODS: Ninety-three patients with primary rectal cancer were prospectively evaluated by thin-section MRI using a pelvic phased-array coil for T and N staging. After radical surgery, MRI results were compared with the histological findings of the resected specimens, and accuracy, sensitivity, specificity, and positive and negative predictive values were assessed. RESULTS: According to pathological staging, 93 tumors were classified based on the TNM classification as follows:Four tumors were pT1, 26 tumors were pT2, 51 tumors were pT3, and 12 tumors were pT4. The MRI had an overall accuracy of 82.8% (77 of 93) for discriminating between early (ie, ≤pT2) and advanced (ie, pT3-pT4) tumors, with a sensitivity of 67% (20 of 30) for early tumors and a sensitivity of 90% (57 of 63) for advanced tumors. It yielded a diagnostic accuracy of 75% (70 of 93) in predicting T stage.Regarding lymph node metastases, the MRI prediction was correct in 58 of 93 patients, which yielded an overall accuracy of 62.4%. CONCLUSIONS: Despite some limitations, thin-section MRI with pelvic phased-array coil can be reliably used in the preoperative evaluation of rectal cancer patients for local tumor staging. It seems highly effective in predicting T stages and can provide useful information regarding lymph node metastases of rectal cancer.

Extraskeletal Ewing's sarcoma presenting as a posterior mediastinal mass.

The Ewing's sarcoma family of tumors is an uncommon group of malignant neoplasms that may be located in both skeletal and extraskeletal regions. Extraskeletal Ewing's sarcoma (EES) is quite rare and predominantly involves the soft tissues of the trunk or the extremities. Herein, we report the case of a 19-year-old female patient who complained of left arm pain. Simple chest radiography revealed an opacity occupying almost the entire left hemithorax. Diagnostic imaging techniques demonstrated a solid contrast-enhanced mass in the posterior mediastinum. There was an evident mediastinal shift, and the left lung was collapsed. Even though lymphoma was considered as an initial diagnosis, a biopsy was taken and its histopathological analysis revealed EES. In the literature, there have been only a few case reports of ESS located in the mediastinum. We conclude that, although this is an unusual location, EES should be contemplated in the differential diagnosis of mediastinal masses.

Neurofibromatosis type 1 presenting with plexiform neurofibromas in two patients: MRI features.

Neurofibromatosis type 1 (NF1), also known as peripheral neurofibromatosis or von Recklinghausen's disease, is one of the most common genetic disorders. It is inherited in an autosomal dominant pattern. Multiple cutaneous neurofibromas are hallmark lesions of NF1. Localized and plexiform neurofibromas of the paraspinal and sacral region are the most common abdominal neoplasms in NF1. Herein, we report two patients with a known history of NF1 presenting with multiple, extensive localized and plexiform neurofibromas. We describe the important distinguishing features of these tumors as seen on magnetic resonance imaging (MRI), including very bright signal intensity and target sign on T2 weighted images.

CT Diagnosis of a Thoracic Aort Aneurysm with Type B Aortic Dissection Clinically Misdiagnosed as Acute Pulmonary Embolism.

A 54-year-old man was admitted to the emergency department, presenting with an acute onset of chest pain and severe respiratory distress symptoms. He was medicated with intravenous analgesia and antihypertensive drugs. The patient was subjected to a chest X-ray which revealed a prominent widening of the mediastinum and pleural effusion on the left side. In laboratory tests-d-dimer level was highly elevated. The patient was clinically interpreted as having an acute pulmonary embolism and referred to the radiology clinic to perform a computed tomography (CT) examination. Contrast-enhanced CT demonstrated that there was no abnormality related to the pulmonary vasculature, but a huge thoracic aorta aneurysm measuring 11 × 8.1 × 7.7 cm in diameter was detected. Accompanying the aneurysm, an intimal flap was also present in the proximal descending thoracic aorta, distal to the origin of the left subclavian artery and extending into the bifurcation level. The patient was therefore diagnosed as having a type B aortic dissection as well. Once these serious conditions were detected, he was immediately transferred to a cardiovascular thoracic surgery hospital for endovascular repairment operation.

A prospective study on the utility of diffusion-weighted and quantitative chemical-shift magnetic resonance imaging in the distinction of adrenal adenomas and metastases.

OBJECTIVE: The purpose of this study was to assess the utility of diffusion-weighted and quantitative chemical-shift magnetic resonance imaging in the differentiation of adrenal adenomas and metastases. METHODS: One hundred eight patients (45 men and 63 women; mean age, 57 years) with 126 adrenal masses were prospectively evaluated by magnetic resonance imaging in this study. Signal intensity and apparent diffusion coefficient (ADC) measurements were performed on axial in- and opposed-phase T1-weighted gradient-echo images and on diffusion-weighted images, respectively. Adrenal signal intensity index (ASII), adrenal-to-spleen chemical-shift ratio (ASR), and ADC values were assessed separately. The threshold values of more than 16.5% for ASII and less than 0.71 for ASR were regarded as highly suggestive of adenoma diagnosis. We also investigated whether a cutoff value for ADC could be found in distinguishing adenomas from metastases. Final diagnoses of adrenal lesions were based on follow-up imaging, histopathologic proof, and adrenal washout study. Apparent diffusion coefficient values of adenomas and metastases were compared by using the Student t test, and ASII and ASR values of the lesions were compared by using the Mann-Whitney U test, and a P < 0.05 was accepted as statistically significant. Receiver operating characteristic curve analysis and sensitivity, specificity, positive and negative predictive values, and overall accuracies were calculated. RESULTS: Final analysis yielded 96 adenomas and 30 metastases. With the commonly used 16.5% threshold value for ASII, we obtained a 94.8% sensitivity, 93.3% specificity, 84.8% positive predictive value, and 97.8% negative predictive value. The overall accuracy was found as 94.4%. When we applied a 0.71 threshold value for ASR, it yielded a 91.7% sensitivity, 100% specificity, 78.9% positive predictive value, and a 100% negative predictive value. The overall accuracy was 93.6%. The mean ADC values were found to be 1.35 ± 0.19 × 10⁻³ mm²/s and 1.32 ± 0.34 × 10⁻³ mm²/s for adenomas and metastases, respectively. The difference between the groups with these ADC values was not statistically significant (P = 0.673). The receiver operating characteristic analysis could not determine a clear cutoff value for the differentiation of adenomas from metastases. CONCLUSIONS: We can advocate that a chemical-shift magnetic resonance imaging using quantitative parameters (ie, ASII and ASR formulas) has an important role in the distinction of adenomas from metastases. These 2 techniques seem to provide close sensitivity, specificity, and accuracy levels. But diffusion-weighted imaging using quantitative ADC measurements is not of value in this differential diagnosis because of the substantial overlapping of ADC values between adenomas and metastases.

Sonographic diagnosis of penile Mondor's disease associated with absence of a dorsal penile artery.

Penile Mondor's disease is an unusual condition, which is characterized by thrombosis in superficial dorsal penile vein. Here, we report the sonographic findings of this disease in a 35-year-old male along with the absence of right dorsal penile artery.

Differentiation of adrenal adenomas from nonadenomas using CT histogram analysis method: a prospective study.

OBJECTIVE: The objective of our study was to prospectively evaluate the effectiveness of computed tomography (CT) histogram analysis method in the differentiation of benign and malignant adrenal masses. MATERIALS AND METHODS: Between March 2007 and June 2008, 94 patients (46 males, 48 females, age range: 30-79 years, mean age: 57.7 years) with 113 adrenal masses (mean diameter: 3.03 cm, range: 1.07-8.02 cm) were prospectively evaluated. These included 66 adenomas, 45 metastases and 2 pheochromocytomas. Histogram analysis method was performed using a circular region of interest (ROI) and mean attenuation, total number of pixels, number of negative pixels and subsequent percentage of negative pixels were detected on both unenhanced and delayed contrast-enhanced CT images for each adrenal mass. A mean attenuation threshold of 10Hounsfield unit (HU) for unenhanced CT and 5% and 10% negative pixel thresholds for both unenhanced and delayed contrast-enhanced CT were calculated by a consensus of at least two reviewers and the correlation between mean attenuation and percentage of negative pixels was determined. Final diagnoses were based on imaging follow-up of minimum 6 months, biopsy, surgery and adrenal washout study. RESULTS: 51 of 66 adenomas (77.3%) showed attenuation values of < or =10HU and 15 (22.7%) adenomas showed more than 10HU on unenhanced CT. All of these adenomas contained negative pixels on unenhanced CT. Eight of 66 (12.1%) adenomas showed a mean attenuation value of < or =10HU on delayed contrast-enhanced scans and 45 adenomas (68.2%) persisted on containing negative pixels. All metastases had an attenuation value of greater than 10HU on unenhanced CT images. 21 of 45 (46.6%) metastases contained negative pixels on unenhanced images but only seven metastases (15.5%) had negative pixels on delayed contrast-enhanced images. Two pheochromocytomas had negative pixels on both unenhanced and delayed contrast-enhanced CT images. Increase in the percentage of negative pixels yielded high correlation with mean attenuation decreases, both on unenhanced and delayed contrast-enhanced CT. Our sensitivity was 90.9% for the 10% negative pixel percentage threshold compared to 77.2% sensitivity for < or =10HU mean attenuation threshold for unenhanced CT. Both methods gave a 100% specificity for the diagnosis of adenoma. We also obtained a 37.9% sensitivity for 5% negative pixel threshold and a slightly lower sensitivity of 28.8% for 10% negative pixel threshold compared to the 12.1% sensitivity of < or =10HU mean attenuation threshold while maintaining 100% specificity for contrast-enhanced CT. CONCLUSION: The CT histogram analysis is a simple and easily applicable method which provides higher sensitivity than the commonly used 10HU threshold mean attenuation method of unenhanced CT and can replace it for the diagnosis of an adenoma. But with contrast-enhanced CT, although 100% specificity is being maintained, the sensitivities obtained are very poor for each method and is therefore likely to limit CT histogram analysis to be used as a clinically useful adjunct in the diagnosis of adenoma.