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18 results found

Breast MRI

Breast MRI is the most sensitive method for detection of breast cancer. Depending on international health regulations, it is either applied for screening of women at high risk for developing breast cancer (e.g. BRCA1 and BRCA2 carriers), as an additional diagnostic test in pretherapeutic breast ...

British Thoracic Society guidelines for pulmonary nodules

British Thoracic Society guidelines for pulmonary nodules were published in August 2015 for the management of pulmonary nodules seen on CT. In the United Kingdom, they supersede the Fleischner Society guidelines. They are based initially on identifying whether the nodule is solid or subsolid an...

Causes of perfusion defects on a VQ scan

There are several causes leading to a perfusion defect on a VQ scan with an acute pulmonary embolus being only one of them: Vascular causes acute pulmonary embolus previous pulmonary embolus (including fat embolism, thromboembolism, air embolism, tumor) vasculitides affecting the pulmonary v...

Computed tomography texture analysis

Computed tomography texture analysis (or CTTA) is a method to obtain new useful biomarkers that provide objective and quantitative assessment of tumor heterogeneity by analyzing the differences and patterns within the pixel values of an image. CTs can be worked with as a matrix of numbers, corre...

Congenital heart disease chest x-ray (an approach)

With the advent of echocardiography, and cardiac CT and MRI, the role of chest x-rays in evaluating congenital heart disease has been largely been relegated to one of historical and academic interest, although they continue to crop up in radiology exams. In most instances a definite diagnosis ca...

Fluid-fluid levels in bone tumors

Fluid-fluid levels in bone tumors is a commonly encountered finding, both in benign as well as malignant bone tumors, and can be used to differentiate between the two. Method of assessment On the sagittal T2W image: measure the length of the largest fluid-fluid level (A) measure the maximum ...

Giant breast masses

Many patients, particularly in developing countries, can present late with giant breast masses. They may be single or multiple and either benign or malignant. Many of these conditions are indistinguishable on physical examination alone. Some of these lesions require mastectomy while others can b...

Hemorrhage exclusion sign (prostate)

The hemorrhage exclusion sign can be a useful MRI finding following prostate biopsy. Pathology The normal prostate produces high concentrations of citrate, which among other properties, acts as an anticoagulant 1. As tumor cells are dysfunctional, they will produce lower levels of citrate than...

Head and neck cancer therapy response interpretation (Hopkins criteria)

The head and neck cancer therapy response interpretation (Hopkins criteria) is a qualitative system of interpretation for therapy response assessment using PET-CT. Background Widely used options for therapy response assessment are clinical examination, histopathology, CT and MR imaging, howeve...

Hyperechoic liver lesions

A hyperechoic liver lesion on ultrasound can arise from a number of entities, both benign and malignant. A benign hepatic hemangioma is the most common entity encountered, but in patients with atypical findings or risk for malignancy, other entities must be considered. Benign hepatic hemangiom...

Intraventricular masses (an approach)

The ventricular system of the brain plays host to a variety of unique tumors, as well as tumors that are more frequently seen elsewhere (e.g. meningiomas). Besides, some intra-axial (parenchymal) masses can be mostly exophytic and thus appear mostly intraventricular. A systematic approach taking...

Pyrexia of unknown origin

A pyrexia of unknown origin, commonly shortened to PUO and also known as a fever of unknown origin (FUO), was originally defined in 1961 as the condition in which the core body temperature is >38.3oC for a period of three weeks or more, with no diagnosis reached after one week of inpatient inves...

RANO criteria for glioblastoma

Response assessment in neuro-oncology criteria (RANO), published in 2010 1, are used to assess response to first-line treatment of glioblastoma (as well as lower grade astrocytoma 3) and have largely superseded the older Macdonald criteria (which only dealt with glioblastoma multiforme) 2. For ...

Selective internal radiation therapy

Selective internal radiation therapy (SIRT), also know as hepatic radioembolization, is a relatively new and developing modality for treating non-resectable liver tumors. The procedure consists of a transcatheter injection of radioactive particles via the hepatic artery.  It is generally consid...

Solitary pulmonary nodule (an approach)

A solitary pulmonary nodule, according to the Nomenclature Committee of the Fleischner Society, is defined as a rounded opacity, well or poorly-defined on a conventional radiograph, measuring up to 3 cm in diameter and is not associated with lymphadenopathy, atelectasis, or pneumonia. Several r...

Sonographic features of malignant lymph nodes

Lymphadenopathy is quite common, and it can be very difficult to differentiate malignant lymphadenopathy from reactive nodal enlargement. Several gray scale and color Doppler features favor malignancy in a lymph node. Gray scale parameters that favor malignancy size: larger-more likely malign...

Split bolus technique

The split bolus technique is a CT imaging investigation used in patients with hematuria aiming to put together, in a single image acquisition, both the nephrographic and renal excretory phases and thus reducing the radiation dose of the study. It is a CT protocol adopted for some institutions fo...

Tumor pseudoresponse

Tumor pseudoresponse, also known just as pseudoresponse, refers to the phenomenon of tumors appearing to respond to a specific treatment on imaging criteria, when the lesion actually remains stable or has even progressed. The term is largely used in brain tumors imaging follow-up, especially fo...

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