Saeed Elojeimy

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.

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.

Potential value of FDG PET-CT in diagnosis and follow-up of TAFRO syndrome

Dear Editor, Beginning in 2010, Takai and other Japanese physicians described a group of patients with a common set of clinical features, including thrombocytopenia (T), ascites (A), myelofibrosis (F), renal dysfunction (R), and organomegaly (O), hence TAFRO [1]. The majority of initial case reports were reported from Japan [2–4]. More recently, TAFRO syndrome has been reported in non-Asian patients around the world. TAFRO syndrome is considered to describe a sub-type of idiopathic multicentric Castleman disease (iMCD) that shares common symptoms and laboratory abnormalities due to a cytokine storm [5]. Whereas human herpes virus-8 (HHV-8) drives the hypercytokinemia in a cohort of immunocompromised patients, the etiology of HHV-8-negative MCD is not known, hence idiopathic MCD (iMCD) [6]. Patients present with heterogeneous clinical features and often deadly multiple organ dysfunction. Lack of familiarity with the disease is a major challenge for clinicians often resulting in delay or lack of proper treatment leading to death [7]. Imaging modalities, such as 18F-Fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT), CT, and ultrasound, are commonly used as part of the work-up in these patients to reach a diagnosis; however, no specific imaging diagnostic criteria have been suggested. Herein, we present the first-reported Hispanic case and a Caucasian case of TAFRO syndrome with iMCD. Both cases received PET-CTas a part of their work-up and evaluation.We discuss findings and potential benefits of PET-CT over CT.

Overview of the Novel and Improved Pulmonary Ventilation-Perfusion Imaging Applications in the Era of SPECT/CT

OBJECTIVE In this article, we describe the concepts of ventilation-perfusion planar, SPECT, and SPECT/CT and outline the advantages of integrated ventilation-perfusion SPECT/CT over planar imaging. We present an overview of the traditional and new applications of ventilation-perfusion scintigraphy. CONCLUSION SPECT/CT has improved the diagnostic accuracy of ventilation-perfusion imaging and opened the door for a new spectrum of applications.

Use of 18F-FDG PET-CT for Detection of Active Disease in Acute Myeloid Leukemia.

A 4-year-old girl with history of acute myeloid leukemia post chemotherapy and stem cell transplant presented with pancytopenia. F-FDG PET-CT (PET-CT) showed multiple metastatic bone and extra medullary soft tissue lesions. Bone marrow biopsy after additional chemotherapy was negative. Concurrent FDG PET-CT demonstrated hypermetabolic foci in the left thigh and hand consistent with residual soft tissue disease. These lesions resolved after further treatment, but a subsequent PET-CT identified a new site of biopsy-proven chloroma. This case illustrates the important role of FDG PET-CT in identifying clinically undetectable extramedullary sites of disease, which may impact subsequent clinical management.

Biliary Leak in the Postsurgical Abdomen: A Primer to HIDA Scan Interpretation

Postsurgical bile leaks can be associated with significant morbidity and even mortality, if not identified and treated at an early phase. Hepatobiliary iminodiacetic acid (HIDA) scan is an important test for detection of bile leaks in the postoperative abdomen. However, the lack of anatomical details on planar images can make interpretation difficult, especially in the setting of altered postsurgical anatomy. Familiarity with the expected postoperative appearance on HIDA scan and correlation with SPECT/CT or other imaging modalities when available are very important. The purpose of this review is to describe the expected findings on HIDA scan after common major abdominal surgeries that involve a change in biliary tree anatomy, and illustrate how to identify biliary leaks and avoid interpretation pitfalls.

Calciphylaxis on bone scan: correlation between molecular and cross-sectional findings

Calciphylaxis is a rare devastating medical condition commonly associated with end-stage renal disease and characterized by extensive microvascular calcifications. We describe a case of calciphylaxis presenting on Tc-99m MDP bone scan imaging with asymmetric radiotracer uptake within the lower extremities corresponding to extensive soft tissue calcifications on Computed tomography. Familiarity with the classic clinical presentation and imaging features of this rare entity may help its early identification and treatment.

123I-FP-CIT and 99mTc-HMPAO in Pathologically Confirmed Progressive Supranuclear Palsy

Molecular brain imaging I-FP-CIT SPECT is an important tool in evaluation of patients with parkinsonism. However, various neurodegenerative etiologies cannot be differentiated by I-FP-CIT SPECT alone. We present a case of progressive supranuclear palsy with abnormal I-FP-CIT SPECT and abnormal Tc-HMPAO SPECT depicted by quantitative analyses but unremarkable MRI 16 months after the onset of symptoms. Brain autopsy demonstrated presence of neuronal and glial tau pathology in both cortical and subcortical regions confirming the diagnosis of progressive supranuclear palsy. This case illustrates potential values of multimodal molecular brain imaging in conjunction with quantitative analysis in the evaluation of movement disorders.

Deep Vein Thrombosis Presenting on Pulmonary Ventilation and Perfusion Scintigraphy.

A 52-year-old woman presenting with dyspnea was referred for a ventilation and perfusion scan (VQ). VQ images (with Tc-DTPA [diethylene triamine pentaacetic acid aerosol] and Tc-MAA [macroaggregated albumin]) initially appeared normal; however, count rates on perfusion images were similar to ventilation images, implying little Tc-MAA had reached the lungs. Spot images of the injected extremity demonstrated focal Tc-MAA accumulation worrisome for a venous thrombus, subsequently confirmed by Doppler ultrasound. Careful attention to relative radiotracer count rates on VQ scans is crucial to ensure diagnostic utility. In addition, abnormal low perfusion radiotracer counts may unveil other pathology with important clinical implications.

Clear-cell chondrosarcoma of the humerus

Clear-cell chondrosarcoma is a rare, low-grade variant of chondrosarcoma characterized by slow growth, low metastatic potential, and a predilection for local recurrence long after treatment. We report an unusually aggressive case of clear-cell chondrosarcoma of the humerus with early metastasis to multiple bony sites including femur, thoracic and lumbar spine, sacrum, and iliac bone. Our purpose is to alert physicians to the sarcomas potential for aggressive behavior, necessitating closer and more frequent followups for early detection and treatment of tumor recurrence and metastasis. We also review the reported imaging and histological features, which may help identify aggressive cases.