Ultradeep sequencing differentiates patterns of skin clonal mutations associated with sun-exposure status and skin cancer burden.

In ultraviolet (UV) radiation-exposed skin, mutations fuel clonal cell growth. The relationship between UV exposure and the accumulation of clonal mutations (CMs) and the correlation between CMs and skin cancer risk are largely unexplored. We characterized 450 individual-matched sun-exposed (SE) and non-SE (NE) normal human skin samples.

Common CT Findings of Novel Coronavirus Disease 2019 (COVID-19): A Case Series.

Given the highly infectious nature of the coronavirus disease 2019 (COVID-19) virus and the lack of proven specific therapeutic drugs and licensed vaccines effective against it, early diagnosis of the disease is of paramount importance. The common chest CT imaging of confirmed COVID-19 cases is discussed here, which shows ground-glass opacity, crazy paving, and consolidation.

Pigmented epithelioid melanocytoma (animal-type melanoma): An institutional experience.

Background: Pigmented epithelioid melanocytoma (PEM) is an uncommon, recently described entity with unknown biologic behavior. There is a high rate of regional metastases, but limited evidence of distant metastases or disease-related death.

Objective: We sought to report our series of patients given a diagnosis of PEM at our institution and provide mutational analysis of genes commonly implicated in melanoma in 2 cases.

Metastatic melanoma with features of blue nevus and tumoral melanosis identified during pembrolizumab therapy.

Metastatic melanoma may exhibit clinical or histologic features of blue nevus. Pembrolizumab therapy is associated with regression and tumoral melanosis. We report on a man with widespread metastatic melanoma on pembrolizumab therapy in whom a blue-grey papule developed on the left side of his neck that clinically resembled a blue nevus and histologically showed features of both blue nevus and tumoral melanosis.

Detection of Occult Invasion in Melanoma In Situ.

Importance: It is unclear why some patients with in situ melanoma develop metastases. Few reports demonstrate occult invasion with immunohistochemistry staining, which were discordant with reports interpreting such staining as false-positive.

Objective: To investigate the occurrence of occult invasive disease within in situ melanoma by using methods to circumvent potential limitations in prior study designs.

2D/3D registration of endoscopic ultrasound to CT volume data.

This paper describes a computer-aided navigation system using image fusion to support endoscopic interventions such as the accurate collection of biopsy specimens. An endoscope provides the physician with real-time ultrasound (US) and a video image. An image slice that corresponds to the corresponding image from the US scan head is derived from a preoperative computed tomography (CT) or magnetic resonance image volume data set using oblique reformatting and displayed side by side with the US image.

Design and application of an assessment protocol for electromagnetic tracking systems.

This paper defines a simple protocol for competitive and quantified evaluation of electromagnetic tracking systems such as the NDI Aurora (A) and Ascension microBIRD with dipole transmitter (B). It establishes new methods and a new phantom design which assesses the reproducibility and allows comparability with different tracking systems in a consistent environment. A machined base plate was designed and manufactured in which a 50 mm grid of holes was precisely drilled for position measurements.

Design and application of an assessment protocol for electromagnetic tracking systems.

This paper defines a simple protocol for competitive and quantified evaluation of electromagnetic tracking systems such as the NDI Aurora (A) and Ascension microBIRD with dipole transmitter (B). It establishes new methods and a new phantom design which assesses the reproducibility and allows comparability with different tracking systems in a consistent environment. A machined base plate was designed and manufactured in which a 50 mm grid of holes was precisely drilled for position measurements.

Calibration and accuracy testing for image-enhanced endoscopy.

New surgical navigation techniques may combine the use of live video from a surgical endoscope with 3D volumetrically-reconstructed images of a patient's anatomy. This image-enhanced endoscopy requires calibration of the endoscope to ensure that the mapping of the real endoscope image to its virtual counterpart is properly performed. The application of a technique to calibrate an endoscope prior to use in a diagnostic or therapeutic procedure is described, as well as a simple yet effective linear method for lens-distortion compensation.

Implementation, calibration and accuracy testing of an image-enhanced endoscopy system.

This paper presents a new method for image-guided surgery called image-enhanced endoscopy. Registered real and virtual endoscopic images (perspective volume renderings generated from the same view as the endoscope camera using a preoperative image) are displayed simultaneously; when combined with the ability to vary tissue transparency in the virtual images, this provides surgeons with the ability to see beyond visible surfaces and, thus, provides additional exposure during surgery. A mount with four photoreflective spheres is rigidly attached to the endoscope and its position and orientation is tracked using an optical position sensor.