Nuclear protein testis (NUT) midline carcinoma is a rare malignancy involving predominantly the midline structures of the body. It is characterized by its genotypic feature of BRD4-NUT translocation, which is in contrast with other malignant processes that are usually categorized based on their histologic/phenotypic features. As these tumors may vary in their histologic presentation, they can be misdiagnosed as poorly differentiated carcinomas. Moreover, they are often very aggressive and associated with high mortality. Therefore, it is extremely important to diagnose them early using computed tomography (CT) and magnetic resonance imaging (MRI) and perform staging and restaging using 18-fluorodeoxyglucose positron emission tomography/computed tomography (18-FDG PET/CT), in addition to accurately identifying them at a microscopic and molecular level. We report a unique case of a sinonasal NUT midline carcinoma that was diagnosed with CT, staged with PET/CT, and restaged using PET/CT and MRI.
Gallbladder adenocarcinoma is an uncommon and serious disease. The primary disease grows rapidly with local invasion into the liver and with distant spread to lymph nodes. It is often detected late, due to which management can be challenging. Despite routine use of computed tomography (CT) and ultrasonography (US) for detection, magnetic resonance imaging (MRI) is often considered for a detailed assessment of the anatomic behavior of these tumors. We share three cases where 18-FDG PET/CT played a role in management thereof.
Neurolymphomatosis (NL) is a rare condition associated with lymphomas in which various structures of the nervous system are infiltrated by malignant lymphocytes. Rarely, it may be the presenting feature of recurrence of lymphoma otherwise deemed to be in remission. It is crucial, as is the case with all types of nodal or visceral involvement of lymphoma, to identify the disease early and initiate treatment with chemotherapy and/or radiation therapy. Positron emission tomography-computed tomography (PET-CT) has been shown to be a sensitive modality for staging, restaging, biopsy guidance, therapy response assessment, and surveillance for recurrence of lymphoma. Magnetic resonance imaging (MRI) is another useful imaging modality, which, along with PET/CT, compliment cerebrospinal spinal fluid (CSF) cytology and electromyography (EMG) in the diagnosis of NL. Performing nerve biopsies to confirm neurolymphomatosis can be challenging and with associated morbidity. The case presented herein illustrates the practical usefulness of these tests in detecting NL as a heralding feature of lymphoma recurrence, especially in the absence of histopathologic correlation.
Neurolymphomatosis (NL) is a rare disease characterized by malignant lymphocytes infiltrating various structures of the nervous system. It typically manifests as a neuropathy involving the peripheral nerves, nerve roots, plexuses, or cranial nerves. It often presents as a complication of lymphoma, but it can be the presenting feature of recurrent lymphoma. It is essential to identify and initiate treatment early with chemotherapy and/or radiation therapy in all cases of nodal or visceral (including neural) involvement with lymphoma. There are various diagnostic tests that can be used for its detection, such as cerebrospinal spinal fluid (CSF) cytology, electromyography (EMG), magnetic resonance imaging (MRI), and positron-emission tomography/computed tomography (PET/CT). FDG-PET/CT is the standard of care in lymphoma staging, restaging, and therapy response assessment, but has an inherent limitation in the detection of disease involvement in the central nervous system. While that is mostly true for visual assessment, there are quantitative methods to measure variation in the metabolic activity in the brain, which in turn helps detect the occurrence of neurolymphomatosis.
Background/Purpose: Dual energy computed tomography (DECT) is emerging as a diagnostic tool for gout, but its sensitivity has not been established. We assessed the sensitivity of DECT for the detection of monosodium urate (MSU) deposits in both non-tophaceous and tophaceous gout.
Methods: Twenty-one patients with gout (per Wallace criteria) agreed to participate in this study funded by Siemens Medical Solutions and underwent DECT of their hands, wrists, elbows, knees, ankles, and feet. Eleven had non-tophaceous gout confirmed by the demonstration of MSU crystals in a joint aspirate. Ten patients had tophaceous gout (crystal-proven in 7), defined by the presence of palpable tophi (n=5), the presence of erosions of the first metatarsal head on radiograph (n=3), or gross MSU deposits in a surgical specimen (n=2). Scans were performed using a SOMATOM Definition Flash Dual Source CT scanner (Siemens Healthcare) with simultaneous acquisition of images at 80 and 140 kV. Post-processing was performed using Siemens software with predefined standard parameters; the threshold ratio parameter was set at 1.36. Sensitivity was defined as the percentage of gout patients who were correctly identified by DECT.
Results: The 21 patients included 17 men, with a mean age of 61 years (range, 43 – 83). Among the 11 patients with non-tophaceous gout, MSU deposits were only detected by DECT in the joint proven to be affected by aspiration in 2 (sensitivity=18%). However, the MSU deposits were evident in ≥1 joint area evaluated by DECT in 7 patients (overall sensitivity=64%), ≥1 clinically affected joint in 4 (57%) patients and ≥1 clinically unaffected joint in 6 (86%) patients. The number of MSU deposits correlated with the maximum recorded serum urate (r2=0.502, p=.022) but not with gout duration. Among the 10 patients with tophaceous gout, 9 had MSU deposits evident by DECT (sensitivity=90%). In an index case of tophaceous gout (Figure), we were surprised to see tophi evident by clinical examination (panel A), 3D volume rendering (Panel B), and bony erosion (panel C-little finger DIP), that were negative by DECT (panel C-lack of green deposits). This prompted us to evaluate the sensitivity of DECT for individual gouty erosions (defined by the presence of an overhanging edge in a joint not affected by severe joint space loss). In 3 patients with extensive foot involvement, MSU deposits were detected by DECT within or immediately adjacent to 13/26 (50%) erosions.
Conclusion: DECT detected MSU deposits in non-tophaceous gout, with 65% sensitivity on scanning of both upper and lower extremity joints and only 18% on scanning of the crystal-proven joint. The sensitivity was 90% in tophaceous gout, but remained inadequate when evaluated on the basis of individual erosive lesions. The detection of MSU deposits by DECT may relate to their density and this could potentially be improved with an adjustment of algorithm input parameters.
Dual-energy computed tomography (DECT) enables material decomposition and virtual monochromatic images by acquiring 2 different energy X-ray data sets. DECT can detect musculoskeletal pathologic conditions that CT alone cannot, and that would otherwise require MR imaging. In this review, the authors discuss several useful techniques and applications of DECT in musculoskeletal research: virtual monochromatic images, virtual noncalcium images, gout, iodine map, and tendons.
Dual-energy computed tomography (DECT) can reduce beam hardening artifacts by synthesizing a
virtual monochromatic image and enables detailed evaluation of prosthetic complications.
DECT can display monosodium urate crystal deposition, which helps to make a correct diagnosis in
atypical gout and precise therapeutic assessment.
DECT iodine maps can delineate soft tissue inflammation of arthritis and may be beneficial for
evaluating peripheral joints because of its high spatial resolution.
When conducting an obesity trial to measure body composition, it’s important to choose imaging options that provide accurate and reliable results. Here are some of the best imaging modalities commonly used for this purpose:
- Dual-Energy X-ray Absorptiometry (DXA): DXA scans are highly accurate and are considered the gold standard for measuring body composition. They can provide information about bone density, fat mass, and lean mass.
- Computed Tomography (CT) Scan: CT scans can offer detailed information about fat distribution within the body, allowing for precise measurements of visceral and subcutaneous fat.
- Magnetic Resonance Imaging (MRI): MRI can provide excellent visualization of fat and lean tissue, offering insights into body composition. It’s non-invasive and does not involve radiation.
- Bioelectrical Impedance Analysis (BIA): While not an imaging modality in the traditional sense, BIA uses electrical impedance to estimate body composition. It’s relatively simple and cost-effective.
- Ultrasound: Ultrasound imaging can be used to assess the subcutaneous fat thickness and muscle thickness at specific locations, making it useful for localized body composition measurements.
- Air Displacement Plethysmography (ADP): ADP, commonly measured using the BodPod, calculates body composition based on the principles of air displacement. It’s non-invasive and provides accurate results.
- Positron Emission Tomography (PET) Scan: PET scans can be used to assess metabolic activity in fat tissue, providing insights into obesity-related metabolic changes.
The choice of imaging modality should depend on factors such as the specific research goals, budget, and accessibility of equipment. It’s often advisable to consult with a medical imaging expert or radiologist to determine the most suitable option for your obesity trial. Additionally, consider ethical and safety aspects when conducting imaging studies involving human participants
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Experience: Scoring Systems
- Eligibility and Safety Assessments
- Body Mass Index (BMI) Score
- Visceral Adiposity Index (VAI)
- Fat Mass Index (FMI)
- Fat-Free Mass Index (FFMI)
- Total Body Fat Percentage
- Sarcopenia Index
- Epicardial Fat Volume Score
- Liver Fat Score
- Muscle Quality Score
- Phase Angle (PhA)
- PET, PET-CT
Since 2007, over 2000 articles were published to cover scientific discoveries, technology break-throughs and special cases. We list here some critically important papers and abstracts.
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