Predictors of Adherence to Antiretroviral Therapy among People Living with HIV in Northern Egypt.

Background: Adherence to medications is a crucial factor in achieving the best therapeutic outcomes for patients who have human immunodeficiency virus (HIV). Little is known about the rate and predictors of adherence to antiretroviral therapy (ART) in Egypt. Objectives: To assess the degree of adherence to ART among people living with HIV/AIDS (PLWHA) in Egypt and to explore the predictors of non-adherence. Methods: A cross-sectional study was conducted from January 2021 to December 2021 on 785 PLWHA attending an ART clinic at the main fever hospital in Alexandria, Egypt. Data collection was done using an interviewing questionnaire and pharmacy database records. Multivariate logistic regression analysis was done to identify the predictors of adherence to ART. Results: The overall adherence rate to ART among the study subjects was 66.7%. Female sex (Adjusted Odds Ratio [95% CI]: 1.73 [1.01-2.96]), intravenous drug use (AOR [95% CI]: 2.87 [1.27-6.49]), fair satisfaction with the health service at ART clinics (OR [95% CI]: 1.86 [1.27-2.73]) appeared as independent predictors of poor adherence. Conclusion: The degree of adherence to ART among PLWHA in Egypt is noticeably high, although it was influenced by several patient-, healthcare-, and community-related factors. This work provides an accurate, standardized tool to measure adherence and identify factors that contribute to non-adherence.

Vitamin D deficiency and vitamin D receptor FokI polymorphism as risk factors for COVID-19.

BACKGROUND: Given the sparse data on vitamin D status in pediatric COVID-19, we investigated whether vitamin D deficiency could be a risk factor for susceptibility to COVID-19 in Egyptian children and adolescents. We also investigated whether vitamin D receptor (VDR) FokI polymorphism could be a genetic marker for COVID-19 susceptibility. METHODS: One hundred and eighty patients diagnosed to have COVID-19 and 200 matched control children and adolescents were recruited. Patients were laboratory confirmed as SARS-CoV-2 positive by real-time RT-PCR. All participants were genotyped for VDR Fok1 polymorphism by RT-PCR. Vitamin D status was defined as sufficient for serum 25(OH) D at least 30 ng/mL, insufficient at 21-29 ng/mL, deficient at <20 ng/mL. RESULTS: Ninety-four patients (52%) had low vitamin D levels with 74 (41%) being deficient and 20 (11%) had vitamin D insufficiency. Vitamin D deficiency was associated with 2.6-fold increased risk for COVID-19 (OR = 2.6; [95% CI 1.96-4.9]; P = 0.002. The FokI FF genotype was significantly more represented in patients compared to control group (OR = 4.05; [95% CI: 1.95-8.55]; P < 0.001). CONCLUSIONS: Vitamin D deficiency and VDR Fok I polymorphism may constitute independent risk factors for susceptibility to COVID-19 in Egyptian children and adolescents. IMPACT: Vitamin D deficiency could be a modifiable risk factor for COVID-19 in children and adolescents because of its immune-modulatory action. To our knowledge, ours is the first such study to investigate the VDR Fok I polymorphism in Caucasian children and adolescents with COVID-19. Vitamin D deficiency and the VDR Fok I polymorphism may constitute independent risk factors for susceptibility to COVID-19 in Egyptian children and adolescents. Clinical trials should be urgently conducted to test for causality and to evaluate the efficacy of vitamin D supplementation for prophylaxis and treatment of COVID-19 taking into account the VDR polymorphisms.

Cytokine profile in Egyptian children and adolescents with COVID-19 pneumonia: A multicenter study.

BACKGROUND: To date, the cytokine profile in children and adolescent with novel coronavirus disease 2019 (COVID-19) has not been reported. OBJECTIVES: We investigated serum levels of a panel of key cytokines in children and adolescent with COVID-19 pneumonia with a primary focus on "cytokine storm" cytokines such as interleukin (IL)-1ß, IL-6, IL-17, IL-2, IL-4, IL-10, interferon (IFN-γ), tumor necrosis factor (TNF)-α, and two chemokines interferon-inducible protein-10 (IP-10) and IL-8. We also studied whether these cytokines could be potential markers for illness severity in COVID-19 pneumonia. METHODS: Ninety-two symptomatic patients aged less than 18 years with confirmed COVID-19 pneumonia and 100 well-matched healthy controls were included in this multi-center study. For all patients, the presence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in respiratory fluid specimens was detected by real-time reverse-transcriptase polymerase chain reaction. We measured serum concentrations of studied cytokines by using flow cytometry. RESULTS: Patients with COVID-19 had significantly higher median IL-1ß, IL-6, IL-8, IL-10, IL-17, TNF-α, and IP-10 serum levels than did control children (all p < 0.01). Patients with severe COVID-19 pneumonia had significantly higher median IL-1ß, IL-6, and IP-10 serum levels as compared with those with moderate COVID-19 pneumonia; all p < 0.01. ROC analysis revealed that three of the studied markers (IL-6, IL-1ß, and IP-10) could predict severe COVID-19 pneumonia cases with the largest AUC for IL-6 of 0.893 (95% confidence interval: 0.84-0.98; p < 0.01). CONCLUSION: Our study shows that pediatric patients with COVID-19 pneumonia have markedly elevated serum IL-1ß, IL-6, IL-8, IL-10, IL-17, TNF-α, and IP-10 levels at the initial phase of the illness indicating a cytokine storm following SARS-CoV-2 infection. Moreover, serum IL-6, IL-1ß, and IP-10 concentrations were independent predictors for severe COVID-19 pneumonia.

Association of Plasminogen Activator Inhibitor 1 (PAI-1) 4G/5G Polymorphism and Susceptibility to SLE in Egyptian Children and Adolescents: A Multicenter Study.

BACKGROUND: Plasminogen activator inhibitor-1 (PAI-1) is a key molecule residing at the nexus between thrombosis and inflammatory processes. Recently, PAI-1 and its gene expression have emerged as a potential candidate for autoimmune disorders such as SLE. OBJECTIVE: To investigate whether the PAI-1 4G/5G polymorphism at position -675 could be a genetic marker for susceptibility to childhood-onset SLE and development of lupus nephritis among Egyptian children and adolescents. METHODS: Three hundred fifty patients diagnosed with childhood-onset SLE and 350 well-matched healthy controls were included in this multi-center study. All subjects were genotyped for the PAI-1 promoter 4G/5G polymorphism at position -675 using PCR- restriction fragment length polymorphism (RFLP). Serum PAI-1 levels were measured by ELISA. RESULTS: The PAI-1 (- 675) 4G/4G genotype was more represented in c-SLE patients, as compared to the control group (38% vs 23%; OR =2.7; [95% CI: 1.47-2.9]; P < 0.001). Patients carrying the PAI-1 4G/4G genotype or 4G allele were more likely to develop lupus nephritis (OR: 3.38; [95% CI: 1.9-5.9]; P <0.001, for the 4G/4G genotype and OR: 2.6; [95% CI: 1.85-3.67]; for the 4G allele; P < 0.01). The PAI-1 4G/4G genotype was associated with higher PAI-1 serum concentrations (mean; 86.6±22.7 ng/mL) as compared to those with a 4G/5G genotype (mean; 48.3±16.5 ng/mL) and the lowest for the 5G/5G genotype (mean; 34.7±11.4 ng/mL); P = 0.004. CONCLUSION: The PAI-1 4G/5G polymorphism may confer susceptibility to childhood-onset SLE and development of lupus nephritis among Egyptian children and adolescents. Moreover, the PAI-1 4G/4G genotype and 4G allele were associated with higher PAI-1 serum levels and higher disease activity scores.

Risk profile of Qatari women treated for infertility in a tertiary hospital: a case-control study.

BACKGROUND: Female infertility is a multifactorial condition constituting a worldwide public health problem. The ability to reproduce is an important product of any marriage, hence infertility may exert a negative impact on physical, financial, social and emotional wellbeing of affected couples. The cornerstone to the management of any disease, including infertility, is prevention. Identifying the modifiable risk factors of female infertility will aid at prevention, early detection, and treatment of medical conditions that can threaten fertility as well as promoting healthy behaviours that can preserve it. AIM: To explore the risk profile of infertility among Qatari women and compare risk factors distribution among primary vs. secondary infertility. METHODOLOGY: A hospital-based case control study was conducted from September 17th, 2017- February 10th, 2018. Cases (n = 136) were enrolled from infertility clinic and controls (pregnant women, n = 272), were enrolled from antenatal clinic, Women Hospital, Hamad Medical Corporation (HMC). Interview questionnaire was utilized to collect data about sociodemographic, risk factors related to infertility and patient health Questionnaire (PHQ)-2. Body Mass Index (BMI) was calculated. Logistic regression was used to identify the associated factors to infertility. Statistical significance was set at 0.05. RESULTS: Forty three primary and ninety three secondary infertility cases were included. Risk factors were age >  35 years (OR = 3.7, 95% CI: 1.41-9.83), second-hand smoking (OR = 2.44, 95% CI:1.26-4.73), steady weight gain (OR = 4.65,, 95% CI: 2.43-8.91), recent weight gain (OR = 4.87, 95% CI: 2.54-9.32), menstrual cycle irregularities (OR = 4.20, 95% CI:1.14-15.49), fallopian tube blockage (OR = 5.45, 95% CI: 1.75-16.95), and symptoms suggestive of sexually transmitted infections (STIs) including chronic lower abdominal/pelvic pain (OR = 3.46, 95% CI: 1.57-7.63), abnormal vaginal discharge (OR = 3.32, 95% CI:1.22-9.03) and dyspareunia (OR = 7.04, 95% CI: 2.76-17.95). Predictive factors for secondary infertility were; longer time from previous conception (OR = 5.8, 95% CI: 3.28-10.21), history of stillbirth (OR = 2.63, 95% CI: 1.04-6.67) or miscarriage (OR = 2.11, 95% CI: 1.21-3.68) and postpartum infection (OR = 3.75, 95% CI: 1.27-11.06). Protective factors were higher education level (OR = 0.44, 95% CI: 0.25-0.78), higher income (OR = 0.17, 95% CI: 0.06-0.49), and awareness/loyalty to fertility window (OR = 0.33, 95% CI: 0.21-0.52 and OR = 0.29, 95% CI: 0.19-0.44, consequently). CONCLUSION: This study highlighted the opportunities to strengthen public health as well as hospital-based health promotion programs importantly toward behavioural-related risk factors (e.g. smoking, obesity, STIs etc.). Moreover, detecting, preventing, and managing modifiable risk factors through awareness, screening and early management of chronic diseases, may contribute at reduction of incidence and severity of infertility. Such interventions can be delivered at premarital, family planning, post-natal and antenatal clinics at primary health care with early referral to secondary care if required.

Association of interleukin-17A gene polymorphisms and susceptibility to systemic lupus erythematosus in Egyptian children and adolescents: a multi-centre study.

BACKGROUND: Recently, the interleukin-17A (IL-17A) gene has emerged as a potential candidate gene for autoimmune disorders, including systemic lupus erythematosus (SLE). OBJECTIVES: This study aimed to investigate whether IL-17A polymorphisms at rs2275913 G/A, rs8193036 C/T and rs3748067 C/T could be susceptibility markers for juvenile-onset SLE (JSLE) and lupus nephritis (LN) in Egyptian children and adolescents. METHODS: In this multi-centre study, we genotyped 320 patients diagnosed with JSLE and 320 matched control children for three IL-17A polymorphisms at rs2275913 G/A, rs8193036 C/T and rs3748067 C/T using TaqMan probe-based real-time polymerase chain reaction. Meanwhile, IL-17A serum levels were assessed using ELISA. RESULTS: The IL-17 rs2275913 A/A genotype and A allele were more represented in JSLE patients compared to the control group (21% vs. 7%, odds ratio (OR) = 3.8, 95% confidence interval (CI) 1.78-5.5, p = 0.001, pBonf = 0.003 for the A/A genotype; 37% vs. 29%, OR = 1.4, 95% CI 1.11-1.8, p = 0.003, pBonf = 0.009 for the A allele. No significant difference was found for IL-17 rs8193036 and rs3748067 single nucleotide polymorphisms (SNPs) in genotype distribution or allele frequencies (p>0.05). Patients carrying the IL-17 rs2275913 A/A genotype and A allele were more likely to develop LN (OR = 5.64, 95% CI 2.39-13.77, pBonf = 0.001 for the A/A genotype; OR = 2.73, 95% CI 1.84-4.07, pBonf = 0.02 for the A allele). CONCLUSION: The IL-17 rs2275913 A allele and A/A genotype were associated with high IL-17 serum levels and may contribute to susceptibility to JSLE and the development of LN in Egyptian children and adolescents. However, no significant association was evident between the studied IL-17A SNPs and other clinical phenotypes, disease activity scores or laboratory profile of JSLE.

Ficolin-1 gene (FCN1) -144 C/A polymorphism is associated with adverse outcome of severe pneumonia in the under-five Egyptian children: A multicenter study.

BACKGROUND: Pneumonia is the foremost cause of child death worldwide. M-ficolin is encoded by the FCN1 gene and represents a novel link between innate and adaptive immunity. OBJECTIVES: To investigate the FCN1 -144 C/A (rs10117466) polymorphism as a potential marker for pneumonia severity and adverse outcome namely complications or mortality in the under-five Egyptian children. METHODS: This was a prospective multicenter study that included 620 children hospitalized with World Health Organization-defined severe pneumonia and 620 matched healthy control children. Polymorphism rs10117466 of the FCN1 gene promoter was analyzed by PCR-SSP, while serum M-ficolin levels were assessed by ELISA. RESULTS: The FCN1 A/A genotype and A allele at the -144 position were more frequently observed in patients compared to the control children (43.4% vs 27.6%; odds ratio [OR]: 1.62; [95% confidence interval {CI}: 1.18-2.2]; for the A/A genotype) and (60.8% vs 52.5%; OR: 1.4; [95% CI: 1.19-1.65]; for the A allele); P < .01. The FCN1 -144 A/A homozygous patients had significantly higher serum M-ficolin concentrations (mean: 1844 ± 396 ng/mL) compared with those carrying the C/C or C/A genotype (mean: 857 ± 278 and 1073 ± 323 ng/mL, respectively; P = .002). FCN1 -144 A/A genotype was an independent risk factor for adverse outcomes in children with severe pneumonia (adjusted OR = 4.85, [95% CI: 2.96-10.25]; P = .01). CONCLUSION: The FCN1 A/A genotype at the -144 position was associated with high M-ficolin serum levels and possibly contributes to enhanced inflammatory response resulting in the adverse outcome of pneumonia in the under-five Egyptian children.

Vaccination coverage in Qatar: Benchmarking with global figures.

Introduction: Vaccination is considered one of the most successful and cost-effective public health interventions of the 20th century. In 2017, Qatar's Expanded Program of Immunization (EPI) provided vaccination services against a comprehensive list of 15 vaccine-preventable diseases. Objectives: To assess the performance of Qatar's national immunization system, identify possible gaps by determining the national vaccination coverage rates, and benchmark these rates against regional and global figures. Methods: The data utilized herein were retrieved from the vaccination coverage estimates generated by the World Health Organization and United Nations International Children's Emergency Fund. Relevant local, regional, and global vaccination coverage figures were manually extracted and then analyzed for six vaccines (DTP3, Pol3, MCV2, HepB, PCV3, and RotaC) in 2017. Percentages and proportions were compared using the Chi-squared test. Results: Vaccination coverage levels in Qatar have surpassed the optimal level of 90% for all vaccines. Compared with international figures, the national coverage exceeds the relevant benchmarks. For DTP3 and Pol3, Qatar achieved 97% coverage compared with 99% coverage in Jordan and 85% coverage globally. For MCV2, Qatar achieved 93% coverage compared with 99% coverage in Jordan and 67% coverage globally. For RotaC, Qatar achieved 97% coverage compared with 96% coverage in Jordan and 28% coverage globally. For HepB, Qatar achieved 97% coverage compared with 43% coverage globally. Conclusions: Compared with the international benchmarks of major vaccines, the vaccination coverage rates in Qatar are high. However, challenges for maintaining high coverage, such as cultural and language barriers, should be addressed.

Iron deficiency, its epidemiological features and feeding practices among infants aged 12 months in Qatar: a cross-sectional study.

OBJECTIVES: To estimate the magnitude of anaemia, iron deficiency (ID), iron deficiency anaemia (IDA) and to explore epidemiological features of ID and feeding practices among infants aged 12 months in Qatar. SETTING: Well baby clinics in 14 randomly selected primary healthcare centres covering all geographical areas on the national level. PARTICIPANTS: Three hundred and six (163 male and 143 female) infants of all nationalities were enrolled. Mothers were asked to complete a predesigned interview questionnaire and infants were blood tested for anaemia, ID and IDA. OUTCOME MEASURES: Cut-off point used to diagnose anaemia was haemoglobin <11.1 g/dL, and to diagnose ID, serum ferritin <6 ug/L with normal C reactive protein. RESULTS: Prevalence of anaemia was 23.5%, ID was 9.2% and IDA was 7.8%. ID was more prevalent among non-Qatari infants compared with Qatari (10.9% vs1.7%, p=0.029), more prevalent among infants born to housewives and to families of low income (p≤0.05). With regard to feeding practice, ID was higher in infants who continued breastfeeding until the age of 1 year and among those who never took infant formula milk (p≤0.05). Mothers who received infant feeding counselling had less ID occurrence among their infants compared with their counterparts who did not receive such counselling (4.2%vs13.4%, p=0.005). CONCLUSION: Although ID and IDA among infants in Qatar are less prevalent compared with many developing countries, still further efforts are needed for improvement towards more developed countries. Efforts should be contextualised and should target the key epidemiological features with special emphasis on infant feeding and infant feeding counselling to mothers.

Scary gas: pathways in the axial body for soft tissue gas dissection (part I).

Gas is often encountered in abnormal locations in the torso, including within soft tissue compartments, vessels, and bones. The clinical significance of this gas ranges from incidental, benign, and self-limited to aggressive infection requiring immediate surgery. As a result of fascial interconnectivity and pressure differences between compartments, gas can dissect distant from its source. Gas can easily dissect between spaces of the extrapleural thorax, subperitoneal abdomen, deep cervical spaces, and subcutaneous tissues. The pleural and peritoneal cavities are normally isolated but may communicate with the other spaces in select situations. Dissection of gas may cause confusion as to its origin, potentially delaying treatment or prompting unnecessary and/or distracting workup and therapies. The radiologist might be the first to suggest and identify a remote source of dissecting gas when the clinical manifestation alone might be misleading. The purpose of this paper, the first in a three-part series on soft tissue gas, is to explore the various pathways by which gas dissects through the superficial and deep compartments of the torso.

Scary gas: a spectrum of soft tissue gas encountered in the axial body (part II).

Ectopic gas in the mediastinum, subperitoneal abdomen, and superficial soft tissues is concerning and can be seen in the setting of trauma, iatrogenic injuries, infection, and inflammation. It can spread along different dissection pathways and may present remotely from the involved organ as described in part one. Recognition of ectopic gas on imaging and differentiating it from other causes of benign gas is very important as these conditions associated with ectopic gas can lead to rapid patient deterioration and usually require urgent surgery. In part two, the different causes of ectopic and benign gas in the torso are reviewed as well as the imaging features that can help to narrow the differential diagnosis.

Scary gas: intravascular, intracranial, and intraspinal ectopic gas (part III).

While ectopic gas can be a sign of dangerous disease requiring immediate medical or surgical intervention, it can also be an incidental and benign finding. Intravenous gas and spinal vacuum gas are common and almost always benign. Intravascular gas is most often related to instrumentation and, if intraarticular, can cause end-organ ischemia; however, treatment is usually supportive. Pneumocephalus arises from a communication with paranasal sinuses or mastoids more often than from meningeal infection and can usually be managed nonoperatively. In part 3 of this series, the different causes of ectopic gas in the vessels, skull, and spine are reviewed, as are the imaging features that can help to narrow the differential diagnosis.

Comprehensive Imaging Review of Abnormalities of the Placenta.

The placenta has a fundamental role in fetal health and functions as an important bridge to normal fetal development throughout pregnancy. A complete fetal ultrasound (US) survey should include full assessment of the placenta for any possible abnormalities. Placental diseases range from abnormal morphology, size, location, extent, and degree of placentation, to abruption and the presence of rare placental neoplasms of benign or malignant nature. Some of these conditions are associated with other diseases including aneuploidies, and their discovery should alert the radiologist to perform a very thorough fetal US examination. At times, a fetal karyotype may be needed to provide additional information. Timely detection of placental abnormalities can alert the clinician regarding the need to make important management decisions to reduce fetal and maternal morbidity and mortality. Familiarity with the normal and abnormal imaging appearance of the placenta is therefore necessary for the radiologist. Ultrasound with Doppler is the initial imaging modality of choice for placental assessment. Magnetic resonance imaging serves as a problem-solving examination in instances where the US findings are equivocal or where additional information is needed. Computed tomography has a limited role in the evaluation of placental disease because of its relatively limited tissue characterization and in particular because of the resultant direct radiation exposure of the fetus. However, in specific instances, particularly after trauma, computed tomography can provide invaluable information for patient management.

Imaging of Pancreas Transplantation and Its Complications.

Whole pancreas transplantation is an effective treatment for obtaining euglycemic status in patients with insulin-dependent diabetes mellitus, and is usually performed concurrent with renal transplantation in the affected patient. This article discusses complex surgical anatomical details of pancreas transplantation including surgical options for endocrine and exocrine drainage pathways. It then describes several possible complications related to surgical factors in the immediate post operative period followed by other complications related to systemic issues, vasculature, and the pancreatic parenchyma.

Evaluation of image registration in subtracted 3D dynamic contrast-enhanced MRI of treated hepatocellular carcinoma.

OBJECTIVE. The objective of our study was to quantify hepatic displacement between breath-holds in multiphasic contrast-enhanced MRI and assess the value of a 3D registration algorithm for displacement correction on subtracted images. MATERIALS AND METHODS. For this retrospective analysis, we evaluated MR images of 25 cirrhotic patients with treated hepatocellular carcinoma (HCC) and at least one coexisting small hepatic cyst that was hypointense on T1-weighted imaging. With the use of an automated 3D deformable registration algorithm, registered base and subtraction images were created using portal venous phase images as the baseline images. The relative displacement of the cysts over the dynamic phases was used to estimate hepatic displacement before and after registration. The width of the subtraction band artifact, HCC lesion conspicuity, and overall subtraction artifact level (i.e., image quality of the entire volume) of the subtraction images were evaluated before and after registration on a 5-point scale (1 = nondiagnostic, 5 = excellent image quality) by two blinded radiologists. Hepatic displacement and subtraction band artifact results were analyzed using the paired Student t test, and the results for HCC lesion conspicuity and image quality of the volume results were analyzed using the Wilcoxon signed rank test. Interobserver agreement was assessed using kappa statistics. RESULTS. The average total cyst displacement on unenhanced, arterial, and delayed phase images was significantly reduced by registration from 4.0, 3.2, and 4.6 mm, respectively, on pre-registered images to 2.4, 1.6, and 1.3 mm on postregistered images (p < 0.01). The mean HCC lesion conspicuity grade improved from 3.4 before registration to 4.4 after registration (p < 0.01), and the mean grade for image quality of the volume improved from 3.3 before registration to 4.6 after registration (p < 0.01). The average width of the subtraction band artifact decreased from 5.3 mm before registration to 2.4 mm after registration, from 6.1 mm before registration to 2.6 mm after registration, and from 5.2 mm before registration to 2.8 mm after registration for the arterial, portal venous, and delayed phase subtractions, respectively (p < 0.01). CONCLUSION. Automated registration of the liver in multiphasic MRI examinations reduced interphasic hepatic displacement, improved the conspicuity of the treated HCC lesion, and improved the overall subtraction image quality.

Subperitoneal extension of disease processes between the chest, abdomen, and the pelvis.

The subserous space is a large, anatomically continuous potential space that interconnects the chest, abdomen, and pelvis. The subserous space is formed from areolar and adipose tissue, and contains branches of the vascular, lymphatic, and nervous systems. As such, it provides one large continuous space in which many disease processes can spread between the chest, abdomen, and the pelvis.

Imaging of complications of common bariatric surgical procedures.

Several techniques for the surgical management of obesity are available to bariatric surgeons. These interventions are performed more frequently with worsening of the obesity epidemic. Radiologists should be familiar with the surgical techniques, normal postoperative appearances, and potential complications for which imaging may be employed to establish a diagnosis to optimize patient care.

Imaging evaluation of maternal complications associated with repeat cesarean deliveries.

The rate of cesarean deliveries continues to rise, while the rate of vaginal delivery after cesarean birth continues to decline. Many women now tend to undergo multiple cesarean deliveries, and therefore the associated chronic maternal morbidities are of growing concern. Accurate diagnosis of these conditions is crucial in maternal and fetal well-being. Many of these complications are diagnosed by imaging, and radiologists should be aware of the type and imaging appearances of these conditions.

Core curriculum illustration: testicular torsion.

This is the 7th installment of a series that will highlight one case per publication issue from the bank of cases available online as part of the American Society of Emergency Radiology (ASER) educational resources. Our goal is to generate more interest in and use of our online materials. To view more cases online, please visit the ASER Core Curriculum and Recommendations for Study online at http://www.aseronline.org/curriculum/toc.htm .

A comprehensive review of the retroperitoneal anatomy, neoplasms, and pattern of disease spread.

A clear understanding of the normal anatomy and pattern of disease spread is important in evaluating many retroperitoneal disorders. Primary retroperitoneal tumors are uncommon, accounting for 0.1%-0.2% of all malignancies in the body; 80%-90% of all primary retroperitoneal tumors are malignant. The primary retroperitoneal neoplasms can be divided into solid or cystic masses. The solid neoplasms can be classified according to their tissue of origin into 3 main categories: mesodermal tumors, neurogenic tumors, and extragonadal germ cell tumors. Computed tomography and magnetic resonance imaging play a vital role in the localization, characterization, evaluation of the extent of local invasion, assessment of metastases, and determination of treatment response for these tumors. The diagnosis of a primary retroperitoneal malignancy is often challenging owing to overlap of imaging findings. A definitive diagnosis can be established only at histopathologic analysis. However, knowledge of the important tumor characteristics, growth pattern, and vascularity can assist in narrowing the differential diagnosis.