Primary Neuroendocrine Tumor of the Ileostomy Stoma on 68Ga-DOTATATE PET/CT.

A 75-year-old man presented with bleeding ileostomy stoma 20 years after total colectomy and end ileostomy for chronic ulcerative colitis. On physical examination, the stoma was mass-like and firm with friable mucosa. Wedge biopsy of the ileostomy stoma revealed well-differentiated neuroendocrine tumor (intermediate grade). Ga-DOTATATE PET/CT showed mass-like focal radiotracer uptake at the ileostomy site without radiotracer-avid lymphadenopathy or distant metastatic disease. No additional sites of neoplasm in the gastrointestinal tract were further identified by endoscopy. The diagnosis of isolated primary neuroendocrine tumor of the ileostomy stoma was confirmed, an extremely rare entity.

Imaging appearance of cystic and solid mesothelioma of the tunica vaginalis.

We present the case of a 32-year-old male who presented with a growing scrotal mass initially diagnosed as benign adenomatoid tumor on ultrasound 6 years prior. Repeat ultrasound showed an abnormal extra-testicular mass with nodular and cystic components and internal vascularity. A computed tomography scan of the abdomen and pelvis confirmed a right extra-testicular scrotal mass with cystic and solid enhancing components. The patient underwent radical orchiectomy and postoperative pathology diagnosed mesothelioma of the tunica vaginalis of the testis. Mesothelioma of the tunica vaginalis of the testis is an exceptionally rare disease. We discuss the risk factors, imaging features, and treatment strategies of the disease.

Massive labial lipomatous hypertrophy in familial partial lipodystrophy seen on computed tomographic angiography.

We present a 28-year-old female with a rare familial partial lipodystrophy. Originally presenting at the age of 14, she began experiencing hypertrophy of the fat in the mons pubis and labia majora regions. By the age of 24 she had disfiguring hypertrophy of these areas with severe fatty overgrowth, similar in nature to that experienced by her father and paternal grandmother. During her workup and planning for suction lipectomy, she underwent computed tomography angiography with the imaging manifestation of severe massive subcutaneous fat hypertrophy; the imaging appearance was only able to be explained after a thorough review of the patient's history and medical literature.

Radiation-Induced Sarcoma on 18F-FDG PET/CT After Treatment of Gorham-Stout Disease of the Maxilla.

Gorham-Stout disease is a rare disorder characterized by proliferation of lymphatic and vascular channels within bone resulting in osteolysis. A 53-year-old man with Gorham-Stout disease involving the left maxilla underwent previous treatment including radiation therapy and intralesional chemotherapeutic injections. He later presented with anemia, facial pain, weight loss, and nasal cavity hemorrhage. CT imaging demonstrated a mass centered within the right maxillary sinus with locoregional involvement. PET/CT showed prominent FDG activity involving the mass centered in the right maxillary sinus with low-grade avidity involving the contralateral maxilla in regions of treated Gorham-Stout disease. Biopsy of the mass confirmed radiation-induced sarcoma.

Evaluation of Adaptive Statistical Iterative Reconstruction-V Reconstruction Algorithm vs Filtered Back Projection in the Detection of Hypodense Liver Lesions: Reader Performance and Preferences.

OBJECTIVE: The aim of the study was to evaluate diagnostic accuracy and readers' experience in the detection of focal liver lesions on computed tomography with Adaptive Statistical Iterative Reconstruction-V (ASIR-V) reconstruction compared with filtered back projection (FBP) scans. METHODS: Fifty-five patients with liver lesions had FBP and ASIR-V scans. Two radiologists independently reviewed both sets of computed tomography scans, identifying and characterizing liver lesions. RESULTS: Adaptive Statistical Iterative Reconstruction-V scans had a reduction in dose length product (P < 0.0001) with no difference in image contrast (P = 0.1805); image noise was less for the ASIR-V scans (P < 0.0001) and contrast-to-noise ratio was better for ASIR-V (P = 0.0002). Both readers found more hypodense liver lesions on the FBP (P = 0.01) scans. Multiple subjective imaging scores were significantly less for the ASIR-V scans for both readers. CONCLUSIONS: Although ASIR-V scans were objectively better, our readers performed worse in lesion detection on them, suggesting a need for better education/experience with this technology during implementation.

The great imitator: IgG4 periaortitis masquerading as an acute aortic syndrome on computed tomographic angiography.

We present the case of a 52-year-old woman who presented to the emergency department with chest and neck pain. Initial cervical spine magnetic resonance imaging shows an abnormal flow void in the left vertebral artery, which prompted a computed tomographic angiogram. This demonstrated a hyperdense thickened ascending aortic wall, which extended into the great vessel origins. Clinically and radiographically interpreted as an acute aortic syndrome and/or intramural hematoma, the patient underwent ascending aortic repair with graft. An unusual aortic and/or periaortic mass was encountered in surgery and final pathology demonstrated IgG4 periaortitis. A rare clinical disease, IgG4-mediated processes are often mimickers of other pathologic entities and frequently lead to misdiagnosis. All pathologically similar, IgG4-mediated disease processes can involve the pancreas, salivary glands, orbits, retroperitoneum, and the vasculature.

Computed Tomographic Angiography of the Abdominal Aorta.

Computed tomographic (CT) angiography (CTA) has become the preferred imaging test of choice for various aortic conditions because of its excellent spatial resolution, rapid image acquisition, and its wide availability. CTA provides a robust tool for planning aortic interventions and diagnosing acute and chronic vascular diseases in the abdomen. CTA is the standard for imaging aneurysms before intervention and evaluating the aorta in the acute setting to assess traumatic injury, dissection, and aneurysm rupture. Knowledge of the imaging features of these disease processes, inflammatory vasculitides, and occlusive atherosclerotic disease is essential for guiding surgical and medical management of patients.

Pulmonary langerhans cell histiocytosis: PET/CT for initial workup and treatment response evaluation.

A 40-year-old man underwent pan-endoscopy owing to abdominal pain. Biopsies of the gastrointestinal tract demonstrated diffuse Langerhans cell histiocytosis. PET/CT was done, with CT demonstrating classic pulmonary manifestations of Langerhans cell histiocytosis that had association with intense FDG uptake on PET. Bowel appeared normal. Treatment was initiated with smoking cessation and 6 cycles of cytarabine. Follow-up PET/CT after initial treatment demonstrated improvement of parenchymal abnormalities seen on CT, with resolution of hypermetabolic activity. Maintenance chemotherapy was initiated. PET/CT is increasingly being used for initial staging and treatment response assessment in this rare disorder.

Evaluation of low-dose CT angiography with model-based iterative reconstruction after endovascular aneurysm repair of a thoracic or abdominal aortic aneurysm.

OBJECTIVE: The objective of our study was to evaluate image quality and overall adequacy of low-dose CT angiography (CTA) with model-based iterative reconstruction (MBIR) in patients who had undergone endovascular aneurysm repair (EVAR) of a thoracic or abdominal aortic aneurysm. MATERIALS AND METHODS: Thirty patients, all of whom had undergone standard-dose CTA performed previously with adaptive statistical iterative reconstruction (ASIR), underwent low-dose CTA for surveillance after EVAR. Two radiologists randomly evaluated both studies, and quality parameters were assessed. The maximal aneurysm diameter was measured, and the images were evaluated to see whether an endoleak was present. The image noise and contrast-to-noise ratio (CNR) were measured. The volume CT dose index and dose-length product were recorded. RESULTS: The mean image score for low-dose CTA was acceptable to very good in all categories of assessment. There was no significant difference between low-dose CTA and standard-dose CTA in the evaluation of the stent lumen. Subjective assessments of stent configuration, aneurysm outline, aortic branch vessel outline, overall adequacy of vascular imaging, and overall adequacy of solid organ imaging were superior on standard-dose CTA. Interobserver agreement for endoleak detection was higher for low-dose CTA. There was no significant difference in the mean aneurysm diameter between the two readers on low-dose CTA and standard-dose CTA. The effective radiation dose for low-dose CTA was lower than standard-dose CTA during both the arterial (mean, 4.4 vs 16.2 mSv, respectively) and the delayed (2.4 vs 6.7 mSv) phase acquisitions. The measured image noise was lower (14.7 vs 19.3 HU) and CNR was higher (25.6 vs 17.1) on the low-dose CTA studies than on the standard-dose CTA studies. CONCLUSION: Low-dose CTA with MBIR enables up to 73% dose reduction as compared with CTA performed with ASIR while maintaining diagnostic adequacy for CTA surveillance of patients who have undergone EVAR of a thoracic or abdominal aortic aneurysm.