Translating Molecules into Imaging-The Development of New PET Tracers for Patients with Melanoma.

Melanoma is a deadly disease that often exhibits relentless progression and can have both early and late metastases. Recent advances in immunotherapy and targeted therapy have dramatically increased patient survival for patients with melanoma. Similar advances in molecular targeted PET imaging can identify molecular pathways that promote disease progression and therefore offer physiological information. Thus, they can be used to assess prognosis, tumor heterogeneity, and identify instances of treatment failure. Numerous agents tested preclinically and clinically demonstrate promising results with high tumor-to-background ratios in both primary and metastatic melanoma tumors. Here, we detail the development and testing of multiple molecular targeted PET-imaging agents, including agents for general oncological imaging and those specifically for PET imaging of melanoma. Of the numerous radiopharmaceuticals evaluated for this purpose, several have made it to clinical trials and showed promising results. Ultimately, these agents may become the standard of care for melanoma imaging if they are able to demonstrate micrometastatic disease and thus provide more accurate information for staging. Furthermore, these agents provide a more accurate way to monitor response to therapy. Patients will be able to receive treatment based on tumor uptake characteristics and may be able to be treated earlier for lesions that with traditional imaging would be subclinical, overall leading to improved outcomes for patients.

Malignant perivascular epithelioid cell tumor of the ileum on 18F-fluorodeoxyglucose positron emission tomography/ computed tomography with pathological correlation.

A 75-year-old woman presented with a 1-month history of abdominal pain. Contrast-enhanced computed tomography (CT) demonstrated a large solid mass in the left lower abdominal quadrant, suspicious for malignancy. Staging with 18F-fluorodeoxyglucose (FDG) positron emission tomography/CT imaging demonstrated intense FDG uptake in the mass with no evidence of metastatic disease. Complete surgical resection was performed, and histopathological analysis confirmed a malignant perivascular epithelioid cell tumor of the ileum.

Extramedullary Myeloma of the Uterus on 18F-FDG PET/CT: A Rare Manifestation of Multiple Myeloma.

Involvement of the uterus by myeloma is an extremely rare manifestation of extramedullary multiple myeloma (MM), denoting a poor prognosis. Extramedullary MM occurs in 7% to 18% of newly diagnosed patients with MM, and 6% to 20% of patients can develop it later. We present a case of extramedullary MM of the uterus suspected on F-FDG PET/CT as a site of disease recurrence in a 47-year-old woman previously in remission. Further evaluation with pelvic MRI identified an infiltrative process involving the uterus, and subsequent tissue sampling confirmed malignant plasma cell infiltration of the uterus. This case highlights a rare site of myeloma recurrence, which can be detected by F-FDG PET/CT.

The urachus revisited: multimodal imaging of benign & malignant urachal pathology.

The urachus is a fibrous tube extending from the umbilicus to the anterosuperior bladder dome that usually obliterates at week 12 of gestation, becoming the median umbilical ligament. Urachal pathology occurs when there is incomplete obliteration of this channel during foetal development, resulting in the formation of a urachal cyst, patent urachus, urachal sinus or urachal diverticulum. Patients with persistent urachal remnants may be asymptomatic or present with lower abdominal or urinary tract symptoms and can develop complications. The purpose of this review is to describe imaging features of urachal remnant pathology and potential benign and malignant complications on ultrasound, CT, positron emission tomography CT and MRI.

Mucinous urachal adenocarcinoma: A potential nonfluorodeoxyglucose-avid pitfall on 18fluorine-fluorodeoxyglucose positron emission tomography/computed tomography.

Mucinous adenocarcinoma of the urachal remnant is a nonurothelial malignancy that may be asymptomatic until locally advanced or metastatic. We describe a 37-year-old woman with invasive ductal breast carcinoma who underwent 18Fluorine-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET) computed tomography (CT) demonstrating a non-FDG avid pelvic mass, initially suspected to represent a pedunculated uterine fibroid. Magnetic resonance imaging revealed a mixed solid-cystic mass separate from the uterus, suspicious for urachal neoplasm, confirmed as mucinous adenocarcinoma on histopathology. Urachal tumors may not be FDG-avid and represent a potential pitfall on FDG PET/CT.

Imaging of the Spine: A Bibliometric Analysis of the 100 Most-Cited Articles.

STUDY DESIGN: A bibliometric review of the literature. OBJECTIVE: The aim of this study was to identify the most highly cited articles relating to imaging of the spine and to analyze the most influential papers and evolving trends in spinal imaging research. SUMMARY OF BACKGROUND DATA: Spinal imaging is being performed with increasing frequency and is an essential step in the diagnosis and treatment planning of spinal pathology. A comprehensive review of the most influential articles in spinal imaging has not been performed, until now. METHODS: A selection of search terms and keywords were inputted into the "Web of Science" database and the most highly cited articles in spinal imaging were selected from high impact factor journals. The top 100 articles were analyzed for year of publication, authorship, publishing journals, institution and country of origin, subject matter, article type, and level of evidence. In addition to total citation count, the number of annual citations was also calculated. Citation counts from Scopus and Google Scholar were also obtained for comparison across other citation index platforms. RESULTS: The most highly cited articles in spinal imaging were published over 30 years, between 1983 and 2013. Total citation count ranged from 98 to 1243 with annual citation count ranging from 3.8 to 91.8. The greatest number of highly cited articles was produced in the United States (n = 49), involved magnetic resonance (n = 73) or multimodal (n = 17) imaging and focused on the lumbar spine (n = 42). The journals that contributed the most articles were Spine and Radiology each publishing 26 articles. CONCLUSION: Our study provided an extensive list of the most historically significant spinal imaging articles, acknowledging the key contributions made to the advancement of this specialist field. LEVEL OF EVIDENCE: 5.

Cardiothoracic manifestations of Erdheim-Chester disease.

Erdheim-Chester disease (ECD) is a rare non-Langerhans cell histiocytosis which can have a broad range of clinical and radiological presentations. Typically, ECD affects multiple organ systems, with skeletal involvement present in almost all ECD patients and cardiothoracic manifestations in more than half. Cardiac and thoracic involvement contributes significantly to morbidity and mortality in affected patients and may have prognostic implications. The diagnosis of ECD can be challenging due to its rarity and similarity to other systemic disease processes. Although the diagnosis can be suggested on imaging, histopathology and immunohistochemistry are required for confirmation. We describe the multimodal imaging features of mediastinal, cardiac, pleural and lung parenchymal ECD. This review identifies the most common radiological manifestations of cardiac and thoracic ECD on contrast-enhanced CT, fluorine18-fludeoxyglucose positron emission tomography/CT and cardiac MRI, and highlights the role of these cross-sectional techniques in disease diagnosis.

Focal Immunotherapy-Induced Pancreatitis Mimicking Metastasis on FDG PET/CT.

A 46-year-old man with metastatic lung adenocarcinoma was treated with pembrolizumab. FDG PET/CT was performed after 3 cycles of treatment and revealed a focal region of pancreatic tail enlargement with an SUVmax value of 7. Following treatment with corticosteroids and discontinuation of pembrolizumab, radiological resolution was observed, and a diagnosis of focal immunotherapy-induced pancreatitis was made. A unique spectrum of FDG-avid adverse events can develop in patients treated with immune-checkpoint inhibitors that may mimic metastatic disease. Knowledge of the radiologic features of these potential imaging pitfalls is crucial among those interpreting FDG PET/CT to allow prompt and decisive treatment.

Perforated Meckel's Diverticulum Masquerading as a Mesenteric Abscess Related to Umbilical Piercing: An Unusual Cause of Acute Abdomen.

Perforated Meckel's diverticulum (MD) is a rare cause of acute abdomen in adults. We describe the case of a 32-year-old man presenting with worsening abdominal pain three weeks following the piercing of his umbilicus. Computed tomography of the abdomen and pelvis demonstrated a small mesenteric collection intimately related to the recently placed navel ornamentation, and a preliminary diagnosis of intra-abdominal abscess secondary to an infected umbilical piercing was made. Initial conservative management with antibiotic therapy was unsuccessful. Subsequent open surgical approach demonstrated an inflamed, perforated Meckel's diverticulum with a small, adjacent infected collection separate from, but in close proximity to the belly-button foreign body. The patient was successfully treated with small bowel resection and followed an uneventful postoperative course.

Balloon-assisted coil embolization (BACE) of a wide-necked renal artery aneurysm using the intracranial scepter C compliant occlusion balloon catheter.

BACKGROUND: True renal artery aneurysms (TRAA) are an uncommon pathology, with a prevalence of less than 1%. Treatment of TRAAs is generally recommended when the aneurysm sac equals or exceeds 2cms. Both wide-necked and main renal artery branch aneurysms represent a challenge for conventional endovascular coil embolization due to the risk of coil migration. MAIN BODY: Intra-procedural remodeling of the aneurysm neck using Balloon Assisted Coil Embolization (BACE) is considered a suitable alternative in challenging cases of visceral artery aneurysms. SHORT CONCLUSION: We describe the novel use of the Scepter C (MicroVention Terumo, Tustin, CA) compliant double lumen neurovascular occlusion balloon in the treatment of a wide-necked branch TRAA in a patient with a solitary kidney.