Surgeon-performed intraoperative transoral ultrasound improves the detection of human papillomavirus-positive head and neck cancers of unknown primary.

Background: Squamous cell carcinomas of unknown primary (SCCUP) are often Human Papillomavirus (HPV)-positive. Due to their small size, extensive surgical workup is required to locate the primary tumors. High-frequency transoral ultrasound (US) may provide improved visualization of these small tumors.

Clinical Evaluation of Deep Learning for Tumor Delineation on F-FDG PET/CT of Head and Neck Cancer.

Artificial intelligence (AI) may decrease FFDG PET/CT-based gross tumor volume (GTV) delineation variability and automate tumor-volume-derived image biomarker extraction. Hence, we aimed to identify and evaluate promising state-of-the-art deep learning methods for head and neck cancer (HNC) PET GTV delineation. We trained and evaluated deep learning methods using retrospectively included scans of HNC patients referred for radiotherapy between January 2014 and December 2019 (ISRCTN16907234).

Response Evaluation Following Radiation Therapy With F-FDG PET/CT: Common Variants of Radiation-Induced Changes and Potential Pitfalls.

Radiation therapy (RT) is one of the cornerstones in cancer treatment and approximately half of all patients will receive some form of RT during the course of their cancer management. Response evaluation after RT and follow-up imaging with F-Fluorodeoxyglucose (F-FDG) positron emission tomography/computed tomography (PET/CT) can be complicated by RT-induced acute, chronic or consequential effects. There is a general consensus that F-FDG PET/CT for response evaluation should be delayed for 12 weeks after completing RT to minimize the risk of false-positive findings.

Disseminated Primary Uterine Hepatoid Adenocarcinoma with α-Fetoprotein Production Demonstrated on F-FDG PET/CT.

We present the F-Fluorodeoxyglucose (F-FDG) positron emission tomography/computed tomography (PET/CT) findings in a 57-year-old woman with post-menopausal bleeding diagnosed with hepatoid adenocarcinoma (HAC) with a primary tumour in the uterine corpus and a highly elevated level of serum-α-fetoprotein (S-AFP) at presentation. HAC is a variant of adenocarcinoma with hepatic differentiation representing a heterogeneous group of neoplasms that morphologically and immunphenotypically resemble hepatocellular carcinoma (HCC) but are of extrahepatic origin. Microscopically, they are usually poorly differentiated adenocarcinomas proliferating in solid sheets or in a trabecular or cord-like arrangement.

Rare Presentation of Late Complications After Undiagnosed Perforated Appendicitis Mimicking Recurrent Endometrial Carcinoma on 18F-FDG PET/CT.

Acute appendicitis is one of the most common causes of acute abdominal pain. Undiagnosed or untreated appendicitis can lead to serious complications. The most frequent complication of acute appendicitis is perforation with subsequent formation of a localized periappendiceal abscess or diffuse bacterial peritonitis.

Baseline FDG PET/CT in free breathing versus deep inspiration breath-hold for pediatric patients with mediastinal lymphoma.

Introduction: The prospective TEDDI protocol investigates the feasibility of radiotherapy delivery in deep inspiration breath-hold (DIBH) for pediatric patients. To secure optimal radiotherapy planning, a diagnostic baseline FDG PET/CT in free breathing (FB) and DIBH was acquired. The anatomical changes in the mediastinum and the effect on PET metrics between the two breathing conditions were assessed for pediatric patients with mediastinal lymphoma.

PET/CT Variants and Pitfalls in Gynecological Cancers.

The role of hybrid imaging with 2-[18F] flourodeoxyglucose (FDG) positron emission tomography and computed tomography (PET/CT) is continuously evolving and now considered standard practice in evaluation of disease stage, treatment response, recurrent disease and follow-up for numerous primary malignancies. In gynecological malignancies FDG PET/CT plays an important role, not only in the assessment of disease in the pre-and post-therapy setting, but also in radiation therapy (RT) planning by defining the metabolically active gross tumor volume (GTV. The glucose analogue radiotracer, FDG, is by far the most utilized radiotracer in PET/CT and is typically seen with high uptake in malignant cells.

Relapse localization in Danish pediatric patients with Hodgkin lymphoma.

Background: Pediatric Hodgkin lymphoma (pHL) is highly curable. However, a minority experience relapse and are subjected to toxic salvage regimens. Investigating the patterns of relapse could help to select the patients and/or the involved sites that would benefit from consolidating radiotherapy.

Imaging for Target Delineation in Head and Neck Cancer Radiotherapy.

The definition of tumor involved volumes in patients with head and neck cancer poses great challenges with the increasing use of highly conformal radiotherapy techniques eg, volumetric modulated arc therapy and intensity modulated proton therapy. The risk of underdosing the tumor might increase unless great care is taken in the process. The information gained from imaging is increasing with both PET and MRI becoming readily available for the definition of targets.

Extensive Subcutaneous Foreign Body Granulomas Associated With "Skin Popping" Demonstrated on 18F-FDG PET/CT.

In illicit drug use, "skin popping" refers to the method of administering drugs by injecting it into the subcutaneous tissue. "Skin popping" can lead to acute and chronic skin manifestations caused by the drug itself and/or by the various adulterants and fillers commonly added to drug substances. Chronic skin manifestations include a foreign-body reaction with formation of granulomas at the site of injection.

18F-FDG PET/CT Findings in Disseminated Genital Herpes in an Immunocompetent Patient With Anaplastic Lymphoma Kinase Rearranged Advanced Nonsmall Cell Lung Cancer.

We present the PET/CT findings of extensive disseminated genital herpes simplex virus infection in a 29-year-old woman known with disseminated anaplastic lymphoma kinase-mutated nonsmall lung cancer. PET/CT revealed extensive involvement of the outer and inner genitalia, multiple lymph nodes extending from the porta hepatis to the groins, and involvement of the liver. Disseminated herpes simplex virus infection is well described in neonates and immunocompromised individuals but very rare in immunocompetent adults as was the case with this patient.

18 F-FDG PET/CT in Extensive Graft-Versus-Host Disease of the Gastrointestinal Tract Following Autologous Stem Cell Transplantation.

Graft-versus-host-disease (GVHD) following stem cell transplantation (SCT) is a common complication in patients that have undergone allogenic SCT but rare in recipients of autologous SCT. Gastro-intestinal tract (GIT)-GVHD can be difficult to diagnose due to non-specific symptoms such as fever, nausea, diarrhea, and vomiting; a histological confirmation is therefore required. Here, we present the findings of a whole-body FDG PET/CT with extensive and multifocal involvement of the GIT in a patient that developed severe acute GVHD 93 days post autologous SCT for Hodgkin's lymphoma.

18F-FDG PET/CT Findings Following Repeated Intramuscular Injections of "Site Enhancement Oil" in the Upper Extremities.

We present the findings on F-FDG PET/CT in a 50-year-old man known to self-administer intramuscular injections with site enhancement oil in the upper extremities. PET images show diffuse pathological high FDG uptake in soft tissue of the upper arms and in scanned portions of the forearms. On the CT images, the muscles in the upper arm are swollen with a moth-eaten appearance and surrounding edema.

Clinical utility of F-FDG positron emission tomography/computed tomography scan vs. Tc-HMPAO white blood cell single-photon emission computed tomography in extra-cardiac work-up of infective endocarditis.

The extra-cardiac work-up in infective endocarditis (IE) comprises a search for primary and secondary infective foci. Whether FDG-PET/CT or WBC-SPECT/CT is superior in detection of clinically relevant extra-cardiac manifestations in IE is unexplored. The objectives of this study were to identify the numbers of positive findings detected by each imaging modality, to evaluate the clinical relevance of these findings and to define the reproducibility for extra-cardiac foci in patients with definite IE.

Pelvic Actinomycosis Associated with an Intrauterine Contraceptive Device Demonstrated on F-18 FDG PET/CT.

A 44-year-old woman with a history of dysmenorrhea, obstipation, and low back pain was investigated for gynecological disorder. Physical examination indicated a "frozen pelvis". Ultrasound examination revealed the ovaries adherent to the uterus, bilateral ovarian cysts, and an intrauterine contraceptive device in situ, which reportedly had been in place for 19 years.

A Case of Asymptomatic Venous Air Embolism Demonstrated on 18F FDG PET/CT.

We present the findings on F FDG PET/CT in connection with iatrogenic venous air embolism. The patient was referred for a posttreatment evaluation PET/CT for peripheral T-cell lymphoma. On the PET images, an intense FDG-uptake was seen in the injected vein.