Items tagged “rewrite”

149 results found
Article

Half-life time

The half-life time is the duration it takes for any physical process to reduce the initial amount to fifty percent of its initial value. Physical half-life time (Tp) The time interval required for an amount of certain radioactive nuclei to decay to half of its original value. Tp is always a co...
Article

Adenoma-carcinoma sequence

The adenoma-carcinoma sequence refers to a stepwise pattern of mutational activation of oncogenes (e.g. K-ras) and inactivation of tumor suppressor genes (e.g. p53) that results in cancer. An oncogene is a gene that has the potential to cause cancer. In tumor cells, these are often mutated or ex...
Article

Dystrophic soft tissue calcification

Dystrophic soft tissue calcification is a type of soft-tissue calcification, which occurs in damaged or necrotic tissue, while the serum level of calcium and phosphorus are normal. It may progress to ossification, in which case a cortical and trabecular bone pattern is visible. An often cited a...
Article

Pancreatic calcifications

Pancreatic calcifications can arise from many etiologies. Punctate intraductal calcifications chronic pancreatitis alcoholic pancreatitis (20-40%) 2  intraductal, numerous, small, irregular preponderant cause of diffuse pancreatic intraductal calcification gallstone pancreatitis (2%) 2 ​m...
Article

Splenic calcification

Splenic calcifications can occur in various shapes and forms and can occur from a myriad of etiological factors. The usual calcification observed in radiographs are the multiple, miliary form presenting as numerous small rounded densities averaging from three to five millimeters in diameter whi...
Article

Neoplasms of the cauda equina (differential)

The differential diagnosis for masses of the cauda equina region is often considered separately to the remainder of the spinal cord. It is often difficult to determine whether masses in this region are intramedullary or intradural-extramedullary. Most common tumors myxopapillary ependymoma by...
Article

Unilateral pulmonary edema

Unilateral pulmonary edema represents only 2% of cardiogenic pulmonary edema with predilection for the right upper lobe and is strongly associated with severe mitral regurgitation 1,2. It is hypothesized that the regurgitation jet is directed towards the right superior pulmonary vein thus prefer...
Article

Gastric outlet obstruction

Gastric outlet obstruction, also known as pyloric obstruction, occurs when a disease or condition blocks the normal emptying of the stomach. Pathology Etiology Gastric outlet obstruction can be due to malignant or benign causes. Malignant adenocarcinoma (second most common 4) GIST lymphom...
Article

MRI safety

MRI scanners, although free from potentially cancer-inducing ionizing radiation found in plain radiography and CT, have a host of safety issues which must be taken very seriously. MRI safety can be divided into: main magnetic field varying magnetic (gradient) fields radiofrequency Main magne...
Article

Adenocarcinoma of the lung

Adenocarcinoma of the lung is the most common histologic type of lung cancer. Grouped under the non-small cell carcinomas of the lung, it is a malignant tumor with glandular differentiation or mucin production expressing in different patterns and degrees of differentiation.  This article brings...
Article

Fat pad impingement syndromes of the knee

In fat pad impingement syndromes, the etiologies are different for each knee fat pad. In anterior suprapatellar fat pad impingement syndrome, the cause is usually due to either a developmental cause related to the anatomy of the extensor mechanism or may be related to abnormal mechanics. In thi...
Article

Hydronephrosis

Hydronephrosis (plural: hydronephroses) is defined as dilatation of the urinary collecting system of the kidney (the calyces, the infundibula, and the pelvis) 1. Hydronephrosis in fetuses and newborns has specific causes that are covered in a separate article. Terminology The term hydroureter...
Article

Cytotoxic cerebral edema

Cytotoxic cerebral edema refers to a type of cerebral edema, most commonly seen in cerebral ischemia, in which extracellular water passes into cells, resulting in their swelling.  The term is frequently used in clinical practice to denote the combination of true cytotoxic edema and ionic cerebr...
Article

Windswept pelvis

A windswept pelvis fracture is a complex bony pelvic injury caused by a combination of unilateral AP compression (open book) injury with a contralateral lateral compression injury.  It occurs when the internal rotation of one iliac wing causes a unilateral sacral compression fracture, while the...
Article

Gastrointestinal neuroendocrine tumors

Gastrointestinal neuroendocrine tumors (GI NETs) are neuroendocrine tumors (NETs) of the GI tract and can be functional or non-functional: functional NETs can be challenging to localize as:  they are often small in size at the time of diagnosis arise in many sites throughout the body non-fun...
Article

Trauma in pregnancy

Trauma is a leading cause of mortality in pregnancy. Pregnancy increases the incidence and severity of abdominal trauma in females.  Epidemiology Trauma affects up to 7% of pregnancies, and the incidence of pregnancy in level 1 trauma patients is estimated to be ~2% 1.  Pathology Etiology 9...
Article

Focused Assessment with Sonography for Trauma (FAST) scan

Focused Assessment with Sonography for Trauma (FAST) scan is a point-of-care ultrasound (POCUS) examination performed at the time of presentation of a trauma patient.  It is invariably performed by a clinician, who should be formally trained, and is considered as an 'extension' of the trauma cl...
Article

Hydroxyapatite deposition disease

Hydroxyapatite crystal deposition disease (HADD) or calcium apatite deposition disease (CADD) is a disease of uncertain etiology characterized by periarticular and intra-articular calcium deposits. The shoulder is the most frequently involved site with classic calcific tendinitis presentation. ...
Article

Diffuse pulmonary nodules (differential diagnosis)

A number of differentials must be kept in mind while approaching diffuse or multiple pulmonary nodules. Interpretation is easier if nodules are the only abnormality. Differential diagnosis These differentials can be narrowed down based on several criteria: Based on appearance  miliary nodule...
Article

Contrast-enhanced ultrasound

Contrast-enhanced ultrasound (CEUS) involves the administration of intravenous contrast agents consisting of microbubbles/nanobubbles of gas. Clinical applications liver hepatic metastasis cystadenoma/cystadenocarcinoma cholangiocarcinoma hepatocellular carcinoma hepatic adenoma focal no...