# CaseStacks — full public content index > Interactive radiology education platform built around call preparation for radiology residents, with 2,100+ diagnostic imaging cases curated by board-certified radiologists. This expanded index lists all publicly accessible content: free cases and the radiology terminology glossary. The compact site index lives at https://casestacks.com/llms.txt. ## Free cases These cases are viewable in full — findings, sample report, discussion, and images — without a subscription. ### Call Preparation - [ASIS avulsion fracture (XR)](https://casestacks.com/call-prep/pediatric-radiographs/peds-msk/pelviship/classic/peds-xr-pelviship-case1) - [Acute appendicitis — Case #1 (CT)](https://casestacks.com/call-prep/body-ct/lower-abdominal-pain/classic/body-ct-lower-abd-case1) - [Acute left ACA and MCA territory infarct (CT)](https://casestacks.com/call-prep/neuro-ct/nontraumatic-brain/classic/neuro-ct-nontrauma-case1) - [Acute subdural hematoma (CT)](https://casestacks.com/call-prep/neuro-ct/traumatic-brain/classic/neuro-ct-trauma-case3) - [Angioinvasive aspergillosis — Case #1 (XR)](https://casestacks.com/call-prep/chest-radiographs/practice-cases/chest-xr-practice-p-case1) - [Anterior mediastinal mass (thymoma) (XR)](https://casestacks.com/call-prep/chest-radiographs/mediastinum/classic/chest-xr-mediastinu-case1) - [Anterior shoulder dislocation with Hill-Sachs fracture — Case #2 (XR)](https://casestacks.com/call-prep/msk-radiographs/shoulderhumerus/classic/msk-xr-shoulderhu-case2) - [Aortic intramural hematoma; Aortic pseudoaneurysm (CT)](https://casestacks.com/call-prep/chest-ct/practice-cases/chest-ct-practice-p-case2) - [Appendicitis with periappendiceal abscess (US)](https://casestacks.com/call-prep/ultrasound/ultrasound-practice/ultrasound-practice-case-1) - [Arteriovenous malformation (AVM) — Case #1 (MRI)](https://casestacks.com/call-prep/neuro-mri/brain/practice/neuro-mri-brain-p-case1) - [Aspiration — Case #1 (CT)](https://casestacks.com/call-prep/chest-ct/non-traumatic/classic/chest-ct-non-trauma-case1) - [Atlanto-occipital dislocation (CT)](https://casestacks.com/call-prep/neuro-ct/spine/classic/neuro-ct-spine-case1) - [Atlantooccipital dissociation — Case #1 (MRI)](https://casestacks.com/call-prep/neuro-mri/spine/classic/neuro-mri-spine-case1) - [Barton fracture (Frykman IV) (XR)](https://casestacks.com/call-prep/msk-radiographs/wristhand/classic/msk-xr-wristhand-case3) - [Buckle fractures — Case #1 (XR)](https://casestacks.com/call-prep/pediatric-radiographs/peds-msk/wristhand/classic/peds-xr-wristhand-case1) - [Cervical spine ligamentous injury — Case #2 (MRI)](https://casestacks.com/call-prep/neuro-mri/spine/classic/neuro-mri-spine-case2) - [Clavicle fracture — Case #1 (XR)](https://casestacks.com/call-prep/msk-radiographs/shoulderhumerus/classic/msk-xr-shoulderhu-case1) - [Clavicle fracture — Case #1 (XR)](https://casestacks.com/call-prep/pediatric-radiographs/peds-msk/shoulderhumerus/classic/peds-xr-shoulderhu-case1) - [Closed-loop bowel obstruction (CT)](https://casestacks.com/call-prep/body-ct/practice-cases/body-ct-practice-p-case2) - [Colles fracture (Frykman IV) — Case #1 (XR)](https://casestacks.com/call-prep/msk-radiographs/wristhand/classic/msk-xr-wristhand-case1) - [Descending necrotizing mediastinitis (CT)](https://casestacks.com/call-prep/neuro-ct/head-and-neck/classic/neuro-ct-head-neck-case2) - [Diffuse alveolar hemorrhage (Goodpasture syndrome) (CT)](https://casestacks.com/call-prep/chest-ct/practice-cases/chest-ct-practice-p-case1) - [Displaced occipital condyle avulsion fracture (CT)](https://casestacks.com/call-prep/neuro-ct/spine/classic/neuro-ct-spine-case3) - [Epidural hematoma; Ligamentous injury (MRI)](https://casestacks.com/call-prep/neuro-mri/spine/practice/neuro-mri-spine-p-case1) - [Epidural hematoma — Case #2 (CT)](https://casestacks.com/call-prep/neuro-ct/traumatic-brain/classic/neuro-ct-trauma-case2) - [Grade 2 germinal matrix hemorrhage (US)](https://casestacks.com/call-prep/ultrasound/ultrasound-classic/ultrasound-classic-case-1) - [Greenstick fractures (XR)](https://casestacks.com/call-prep/pediatric-radiographs/peds-msk/wristhand/classic/peds-xr-wristhand-case2) - [Hepatic abscess — Case #1 (CT)](https://casestacks.com/call-prep/body-ct/upper-abdominal-pain/classic/body-ct-upper-abd-case1) - [Hepatic laceration; Mesenteric injuries with active hemorrhage; Mediastinal hematoma; Traumatic lumbar hernia (CT)](https://casestacks.com/call-prep/body-ct/trauma/classic/body-ct-trauma-case1) - [Intussusception — Case #1 (XR)](https://casestacks.com/call-prep/pediatric-radiographs/peds-abdomen/practice/peds-xr-abdomen-p-case1) - [Large bowel obstruction — Case #2 (XR)](https://casestacks.com/call-prep/kub/classic/kub-classic-case2) - [Layering pleural effusion (XR)](https://casestacks.com/call-prep/chest-radiographs/pleura/classic/chest-xr-pleura-case2) - [Left ACA territory infarct (CT)](https://casestacks.com/call-prep/neuro-ct/nontraumatic-brain/classic/neuro-ct-nontrauma-case3) - [Leukemic bone involvement — Case #2 (XR)](https://casestacks.com/call-prep/pediatric-radiographs/peds-msk/nontraumatic/classic/peds-xr-nontraumat-case2) - [Lipohemarthrosis — Case #1 (XR)](https://casestacks.com/call-prep/msk-radiographs/femurknee/classic/msk-xr-femurknee-case1) - [Lipohemarthrosis — Case #1 (XR)](https://casestacks.com/call-prep/pediatric-radiographs/peds-msk/femurknee/classic/peds-xr-femurknee-case1) - [Lobar pneumonia (CT)](https://casestacks.com/call-prep/chest-ct/non-traumatic/classic/chest-ct-non-trauma-case2) - [Ludwig angina — Case #1 (CT)](https://casestacks.com/call-prep/neuro-ct/head-and-neck/classic/neuro-ct-head-neck-case1) - [Maisonneuve fracture — Case #3 (XR)](https://casestacks.com/call-prep/pediatric-radiographs/peds-msk/anklefoot/classic/peds-xr-anklefoot-case3) - [Maisonneuve fracture — Case #3 (XR)](https://casestacks.com/call-prep/msk-radiographs/anklefoot/classic/msk-xr-anklefoot-case3) - [Meconium aspiration — Case #3 (XR)](https://casestacks.com/call-prep/pediatric-radiographs/peds-chest/classic/peds-xr-chest-case3) - [Middle mediastinal mass (duplication cyst) (XR)](https://casestacks.com/call-prep/chest-radiographs/mediastinum/classic/chest-xr-mediastinu-case2) - [Necrotizing enterocolitis (NEC) — Case #2 (XR)](https://casestacks.com/call-prep/pediatric-radiographs/peds-abdomen/classic/peds-xr-abdomen-case2) - [Normal — Case #1 (XR)](https://casestacks.com/call-prep/pediatric-radiographs/peds-chest/practice/peds-xr-chest-p-case1) - [Occipital condyle fracture — Case #2 (CT)](https://casestacks.com/call-prep/neuro-ct/spine/classic/neuro-ct-spine-case2) - [Olecranon fracture — Case #2 (XR)](https://casestacks.com/call-prep/msk-radiographs/elbowforearm/classic/msk-xr-elbowforea-case2) - [Open Weber type C ankle fracture (XR)](https://casestacks.com/call-prep/msk-radiographs/anklefoot/classic/msk-xr-anklefoot-case2) - [Patellar dislocation (XR)](https://casestacks.com/call-prep/msk-radiographs/femurknee/classic/msk-xr-femurknee-case3) - [Pathological fracture through a simple bone cyst (XR)](https://casestacks.com/call-prep/pediatric-radiographs/peds-msk/nontraumatic/classic/peds-xr-nontraumat-case1) - [Pneumatosis Ileus (XR)](https://casestacks.com/call-prep/kub/practice/kub-practice-p-case1) - [Pneumonia and empyema (US)](https://casestacks.com/call-prep/ultrasound/ultrasound-classic/ultrasound-classic-case-2) - [Pneumoperitoneum — Case #1 (XR)](https://casestacks.com/call-prep/pediatric-radiographs/peds-abdomen/classic/peds-xr-abdomen-case1) - [Posterior shoulder dislocation with reverse Hill-Sachs and Bankart fractures (XR)](https://casestacks.com/call-prep/msk-radiographs/shoulderhumerus/classic/msk-xr-shoulderhu-case3) - [Pulmonary contusion — Case #1 (CT)](https://casestacks.com/call-prep/chest-ct/traumatic/classic/chest-ct-traumatic-case1) - [Pulmonary laceration (CT)](https://casestacks.com/call-prep/chest-ct/traumatic/classic/chest-ct-traumatic-case2) - [Radial head fracture — Case #2 (XR)](https://casestacks.com/call-prep/pediatric-radiographs/peds-msk/elbowforearm/classic/peds-xr-elbowforea-case2) - [Radial head fracture — Case #1 (XR)](https://casestacks.com/call-prep/msk-radiographs/elbowforearm/classic/msk-xr-elbowforea-case1) - [Respiratory distress syndrome (RDS) (XR)](https://casestacks.com/call-prep/pediatric-radiographs/peds-chest/classic/peds-xr-chest-case1) - [Rickets — Case #3 (XR)](https://casestacks.com/call-prep/pediatric-radiographs/peds-msk/nontraumatic/classic/peds-xr-nontraumat-case3) - [Right PCA territory infarct (CT)](https://casestacks.com/call-prep/neuro-ct/nontraumatic-brain/classic/neuro-ct-nontrauma-case2) - [Right lower lobe collapse (XR)](https://casestacks.com/call-prep/chest-radiographs/lung/classic/chest-xr-lung-case3) - [Right middle lobe collapse (XR)](https://casestacks.com/call-prep/chest-radiographs/lung/classic/chest-xr-lung-case2) - [Right upper lobe collapse (XR)](https://casestacks.com/call-prep/chest-radiographs/lung/classic/chest-xr-lung-case1) - [Ruptured left PICA aneurysm (CT)](https://casestacks.com/call-prep/neuro-ct/nontraumatic-brain/practice/neuro-ct-nontrauma-p-case1) - [Scalp contusion (CT)](https://casestacks.com/call-prep/neuro-ct/traumatic-brain/classic/neuro-ct-trauma-case1) - [Simple pleural effusion (XR)](https://casestacks.com/call-prep/chest-radiographs/pleura/classic/chest-xr-pleura-case1) - [Small bowel obstruction — Case #1 (XR)](https://casestacks.com/call-prep/kub/classic/kub-classic-case1) - [Small vessel vasculitis (CT)](https://casestacks.com/call-prep/body-ct/practice-cases/body-ct-practice-p-case1) - [Smith fracture (Frykman IV) (XR)](https://casestacks.com/call-prep/msk-radiographs/wristhand/classic/msk-xr-wristhand-case2) - [Stable pelvic ring injury (LC I) — Case #2 (XR)](https://casestacks.com/call-prep/msk-radiographs/pelviship/classic/msk-xr-pelviship-case2) - [Supracondylar humeral fracture — Case #1 (XR)](https://casestacks.com/call-prep/pediatric-radiographs/peds-msk/elbowforearm/classic/peds-xr-elbowforea-case1) - [Tension pneumothorax (XR)](https://casestacks.com/call-prep/chest-radiographs/practice-cases/chest-xr-practice-p-case2) - [Thrombotic infarct (MRI)](https://casestacks.com/call-prep/neuro-mri/brain/classic/neuro-mri-brain-case1) - [Tibial plateau fracture — Case #2 (XR)](https://casestacks.com/call-prep/pediatric-radiographs/peds-msk/femurknee/classic/peds-xr-femurknee-case2) - [Tibial plateau fracture (Schatzker VI) — Case #2 (XR)](https://casestacks.com/call-prep/msk-radiographs/femurknee/classic/msk-xr-femurknee-case2) - [Transient tachypnea of the newborn (TTN) — Case #2 (XR)](https://casestacks.com/call-prep/pediatric-radiographs/peds-chest/classic/peds-xr-chest-case2) - [Unstable pelvic ring injury (APC II) — Case #1 (XR)](https://casestacks.com/call-prep/msk-radiographs/pelviship/classic/msk-xr-pelviship-case1) - [Venous sinus thrombosis (MRI)](https://casestacks.com/call-prep/neuro-mri/brain/classic/neuro-mri-brain-case3) - [Vertical shear pelvic ring injury (XR)](https://casestacks.com/call-prep/msk-radiographs/pelviship/classic/msk-xr-pelviship-case3) - [Watershed infarcts (MRI)](https://casestacks.com/call-prep/neuro-mri/brain/classic/neuro-mri-brain-case2) - [Weber type B ankle fracture — Case #1 (XR)](https://casestacks.com/call-prep/msk-radiographs/anklefoot/classic/msk-xr-anklefoot-case1) - [Weber type B fracture — Case #1 (XR)](https://casestacks.com/call-prep/pediatric-radiographs/peds-msk/anklefoot/classic/peds-xr-anklefoot-case1) - [Weber type C fracture; Ankle dislocation (XR)](https://casestacks.com/call-prep/pediatric-radiographs/peds-msk/anklefoot/classic/peds-xr-anklefoot-case2) ### Neuro Fellowship - [Alzheimer disease (MRI)](https://casestacks.com/neuro-fellowship/neurodegenerative/nd-case-1) - [External auditory canal atresia (MRI)](https://casestacks.com/neuro-fellowship/congenital-hearing-loss/chl-case-1) - [IDH-mutant astrocytoma — Case #1 (MRI)](https://casestacks.com/neuro-fellowship/brain-tumors/practice/bt-practice-case-1) - [Pilocytic astrocytoma (MRI)](https://casestacks.com/neuro-fellowship/brain-tumors/classic/bt-classic-case-1) - [Pilomyxoid astrocytoma (MRI)](https://casestacks.com/neuro-fellowship/brain-tumors/classic/bt-classic-case-2) - [Subependymal giant cell astrocytoma (SEGA) (MRI)](https://casestacks.com/neuro-fellowship/brain-tumors/classic/bt-classic-case-3) ## Radiology terminology glossary Definitions as used across CaseStacks case write-ups. Each term links to its glossary page. - **[air-fluid level(s)](https://casestacks.com/terms/air-fluid-levels)**: A term describing a distinct separation between air and fluid within a structure, most commonly used in the paranasal sinuses and bowel. Bowel air-fluid levels are best seen with upright imaging - **[anastomosis](https://casestacks.com/terms/anastomosis)**: Surgical connection of two or more bowel segments - **[anechoic](https://casestacks.com/terms/anechoic)**: Absent signal (completely black) within a structure on ultrasound - **[aneurysm](https://casestacks.com/terms/aneurysm)**: Abnormal dilation or ballooning of an artery - **[ankle mortise](https://casestacks.com/terms/ankle-mortise)**: The joint space formed between the distal tibia, medial and lateral malleoli, and talar dome - **[ankylosis](https://casestacks.com/terms/ankylosis)**: Osseous or fibrous fusion across a joint - **[anterolisthesis](https://casestacks.com/terms/anterolisthesis)**: Abnormal anterior position of a vertebral body relative to the vertebral body immediately inferior to it - **[aortopulmonary window](https://casestacks.com/terms/aortopulmonary-window)**: The portion of the mediastinum between the aortic arch and left pulmonary artery - **[ascites](https://casestacks.com/terms/ascites)**: An abnormal collection of fluid between the visceral and parietal peritoneal layers - **[atelectasis](https://casestacks.com/terms/atelectasis)**: Alveolar collapse within a portion or all of a pulmonary lobe - **[blebs](https://casestacks.com/terms/blebs)**: Gas-filled structures along the periphery of the lungs, often at the apex, measuring < 1 cm in diameter - **[blowout fracture](https://casestacks.com/terms/blowout-fracture)**: A fracture of an internal orbital wall, sparing the orbital rim, with outward displacement of fracture fragments - **[bronchiectasis](https://casestacks.com/terms/bronchiectasis)**: Abnormal fixed bronchial dilation - **[bullae](https://casestacks.com/terms/bullae)**: A gas-filled structure along the periphery of the lung, often at the apex, measuring > 1 cm in diameter - **[burst fracture](https://casestacks.com/terms/burst-fracture)**: A spine fracture resulting from axial loading, which typically results in multiple bone fragments, vertebral body height loss, and displacement of bone fragments into the spinal canal - **[cardiac silhouette](https://casestacks.com/terms/cardiac-silhouette)**: The heart outline on a chest radiograph - **[cerebellopontine angle](https://casestacks.com/terms/cerebellopontine-angle)**: A normally present, triangular space containing CSF bounded by the cerebellum posteriorly, the pons medially, and the petrous temporal bone laterally - **[cervicomedullary junction](https://casestacks.com/terms/cervicomedullary-junction)**: The junction between the brainstem and the spinal cord - **[cholelithiasis](https://casestacks.com/terms/cholelithiasis)**: A synonym for gallstones - **[color Doppler](https://casestacks.com/terms/color-doppler)**: An ultrasound technique used to detect blood flow and measure its speed and direction - **[comminuted](https://casestacks.com/terms/comminuted)**: A fracture resulting in greater than 2 bone fragments - **[consolidation](https://casestacks.com/terms/consolidation)**: A lung opacity that obscures the underlying lung architecture - **[coup-contrecoup](https://casestacks.com/terms/coup-contrecoup)**: A traumatic brain injury in which there is hemorrhage and/or damage to the brain at the site of impact (coup) and directly opposite the site of impact (contrecoup) - **[diaphysis](https://casestacks.com/terms/diaphysis)**: The shaft of a long bone - **[diastasis](https://casestacks.com/terms/diastasis)**: Abnormal separation of two adjacent bones - **[emphysema](https://casestacks.com/terms/emphysema)**: Abnormal lucent areas in the lungs resulting from damage to alveoli - **[enhancement](https://casestacks.com/terms/enhancement)**: Increase in attenuation (CT) or intensity (MRI) of a structure after administration of IV contrast - **[enhancing](https://casestacks.com/terms/enhancing)**: A structure that increases in attenuation (CT) or intensity (MRI) after administration of IV contrast - **[enucleation](https://casestacks.com/terms/enucleation)**: Surgical removal of the eyeball (globe) - **[epidural](https://casestacks.com/terms/epidural)**: Occurring external to the dura - **[epiphysis](https://casestacks.com/terms/epiphysis)**: The end of a long bone, positioned between the joint and the growth plate (physis) - **[ex vacuo](https://casestacks.com/terms/ex-vacuo)**: Enlargement of a structure (most commonly the ventricles) due to volume loss in the surrounding tissues - **[fat stranding](https://casestacks.com/terms/fat-stranding)**: Abnormal increased attenuation within fat, indicative of edema - **[groundglass](https://casestacks.com/terms/groundglass)**: A hazy lung opacity that does not obscure the underlying lung architecture, including the blood vessels and bronchi - **[honeycombing](https://casestacks.com/terms/honeycombing)**: Clustered, stacked, small cystic structures along the periphery of the lungs - **[hydrocele](https://casestacks.com/terms/hydrocele)**: An abnormal collection of fluid between the visceral and parietal layers of the tunica vaginalis - **[hydrocephalus](https://casestacks.com/terms/hydrocephalus)**: Enlargement of the ventricular system due to inadequate CSF drainage - **[hydronephrosis](https://casestacks.com/terms/hydronephrosis)**: Abnormal dilation of the renal collecting system - **[hydroureteronephrosis](https://casestacks.com/terms/hydroureteronephrosis)**: Abnormal dilation of the renal collecting system and ureter - **[hyperattenuating/hyperattenuation](https://casestacks.com/terms/hyperattenuatinghyperattenuation)**: Brighter signal of a structure on CT or radiographs compared to surrounding structures - **[hyperechoic](https://casestacks.com/terms/hyperechoic)**: Brighter signal of a structure on ultrasound compared to surrounding structures - **[hyperenhancement](https://casestacks.com/terms/hyperenhancement)**: A greater intensity of enhancement than expected, i.e. a structure that appears brighter on postcontrast imaging than it normally does - **[hyperintense/hyperintensity](https://casestacks.com/terms/hyperintensehyperintensity)**: Brighter signal of a structure on MRI compared to surrounding structures - **[hypermetabolic](https://casestacks.com/terms/hypermetabolic)**: Specific to FDG-PET, this term is used to describe tissues that have more radiotracer uptake compared to the background and are therefore thought to be more metabolically active - **[hypoattenuating/hypoattenuation](https://casestacks.com/terms/hypoattenuatinghypoattenuation)**: Darker signal of a structure on CT or radiographs compared to surrounding structures - **[hypoechoic](https://casestacks.com/terms/hypoechoic)**: Darker signal of a structure on ultrasound compared to surrounding structures - **[hypointense/hypointensity](https://casestacks.com/terms/hypointensehypointensity)**: Darker signal of a structure on MRI compared to surrounding structures - **[infarct](https://casestacks.com/terms/infarct)**: An area of brain tissue death resulting from inadequate blood flow - **[interlobular septal thickening](https://casestacks.com/terms/interlobular-septal-thickening)**: Abnormal thickening of the connective tissue planes separating secondary pulmonary lobules - **[intramedullary](https://casestacks.com/terms/intramedullary)**: Within the substance of the spinal cord - **[intraparenchymal](https://casestacks.com/terms/intraparenchymal)**: Occurring within the brain parenchyma - **[isoattenuating/isoattenuation](https://casestacks.com/terms/isoattenuatingisoattenuation)**: Equal signal of a structure on CT or radiographs compared to surrounding structures - **[isoechoic](https://casestacks.com/terms/isoechoic)**: Equal signal of a structure on ultrasound compared to surrounding structures - **[isointense/isointensity](https://casestacks.com/terms/isointenseisointensity)**: Equal signal of a structure on MRI compared to surrounding structures - **[joint effusion](https://casestacks.com/terms/joint-effusion)**: An abnormal collection of fluid within a joint space - **[juxtacortical](https://casestacks.com/terms/juxtacortical)**: Occurring in the white matter just beneath the cerebral cortex - **[kyphosis](https://casestacks.com/terms/kyphosis)**: Abnormal forward curvature of the spine, causing a patient to appear hunched over - **[lipohemarthrosis](https://casestacks.com/terms/lipohemarthrosis)**: A collection of fat and hemorrhage within a joint, usually resulting from an intra-articular fracture - **[lucency / lucencies](https://casestacks.com/terms/lucency-lucencies)**: An area of abnormal hypoattenuation (radiographs or CT), often used to describe findings within the lung or pleura - **[metaphysis](https://casestacks.com/terms/metaphysis)**: The flared portion of a long bone between the diaphysis and physis - **[myelomeningocele](https://casestacks.com/terms/myelomeningocele)**: An open neural tube defect in which a portion of the spinal cord and the associated meninges bulge through a developmental defect in the spinal canal without an intact overlying skin covering - **[nonunion](https://casestacks.com/terms/nonunion)**: A nonhealing fracture - **[opacified](https://casestacks.com/terms/opacified)**: Abnormal filling of a usually gas-filled structure, like the paranasal sinuses or mastoid air cells, with fluid or other tissue - **[opacity / opacities](https://casestacks.com/terms/opacity-opacities)**: An area of abnormal hyperattenuation (radiographs or CT), often used to describe findings within the lungs or pleura - **[osteophyte](https://casestacks.com/terms/osteophyte)**: Irregular bone spurs that grow along the edges of joints due to osteoarthritis - **[pars interarticularis](https://casestacks.com/terms/pars-interarticularis)**: The bony bridge connecting the superior and inferior articulating facets - **[pathologic fracture](https://casestacks.com/terms/pathologic-fracture)**: A fracture occurring in a bone that is abnormally weakened - **[pericardial effusion](https://casestacks.com/terms/pericardial-effusion)**: An abnormal collection of fluid between the visceral and parietal pericardial layers - **[periosteal reaction](https://casestacks.com/terms/periosteal-reaction)**: New bone formation along the cortex in response to injury or irritation - **[peripheral enhancement / peripherally-enhancing / ring enhancement / ring enhancing](https://casestacks.com/terms/peripheral-enhancement-peripherally-enhancing-ring-enhancement-ring-enhancing)**: Bright signal around the edges of a lesion that develops after IV contrast administration - **[physis](https://casestacks.com/terms/physis)**: A synonym for growth plate - **[pleural effusion](https://casestacks.com/terms/pleural-effusion)**: An abnormal collection of fluid between the visceral and parietal pleural layers - **[pneumothorax](https://casestacks.com/terms/pneumothorax)**: An abnormal collection of gas between the visceral and parietal pleural layers - **[postcontrast](https://casestacks.com/terms/postcontrast)**: Imaging performed after the administration of IV contrast - **[posterior acoustic enhancement](https://casestacks.com/terms/posterior-acoustic-enhancement)**: An ultrasound artifact resulting when a structure allows easy passage of sound waves through it with minimal absorption and reflection, resulting in a band of apparent hyperechoic signal deep to the structure - **[posterior acoustic shadowing](https://casestacks.com/terms/posterior-acoustic-shadowing)**: An ultrasound artifact resulting when a structure reflects or absorbs most of the sound waves, resulting in a band of apparent hypoechoic signal deep to the structure - **[proptosis](https://casestacks.com/terms/proptosis)**: Abnormal eyeball (globe) protrusion - **[pseudocapsular enhancement](https://casestacks.com/terms/pseudocapsular-enhancement)**: A term used in the description of hepatocellular carcinoma to describe the capsule-like rim of bright signal around the tumor on delayed postcontrast imaging that results from rapid washout of contrast from the central part of the tumor - **[radiodensities](https://casestacks.com/terms/radiodensities)**: Hyperattenuating structures - **[radiopaque](https://casestacks.com/terms/radiopaque)**: Synonymous with hyperattenuating (appearing brighter than surrounding structures on CT or radiographs) - **[radiotracer](https://casestacks.com/terms/radiotracer)**: A radioactive compound used for medical imaging - **[regurgitation](https://casestacks.com/terms/regurgitation)**: Abnormal retrograde flow of blood across a cardiac valve plane - **[restricted diffusion](https://casestacks.com/terms/restricted-diffusion)**: Having hyperintense signal on DWI and matching hypointense signal on ADC compared to surrounding structures - **[retroareolar](https://casestacks.com/terms/retroareolar)**: Directly underneath the nipple - **[retrosternal clear space](https://casestacks.com/terms/retrosternal-clear-space)**: A normally present area of relative lucency located between the sternum and the ascending aorta on a lateral chest radiograph - **[scout](https://casestacks.com/terms/scout)**: An image (often a radiograph) taken to help plan an imaging study or procedure - **[subarachnoid](https://casestacks.com/terms/subarachnoid)**: Occurring in the space between the arachnoid and pia mater - **[subdural](https://casestacks.com/terms/subdural)**: Occurring in the space between the dura and arachnoid mater - **[subependymal edema](https://casestacks.com/terms/subependymal-edema)**: Also known as transependymal edema, this type of brain edema occurs around the edges of the ventricular system due to elevated intraventricular pressure, as can be seen with hydrocephalus - **[subfalcine herniation](https://casestacks.com/terms/subfalcine-herniation)**: Abnormal displacement of brain tissue underneath the falx cerebri, crossing midline - **[subluxation](https://casestacks.com/terms/subluxation)**: Partial dislocation of a joint - **[subpleural reticulation](https://casestacks.com/terms/subpleural-reticulation)**: Linear opacities along the periphery of the lungs - **[sulcal effacement](https://casestacks.com/terms/sulcal-effacement)**: Seeming disappearance of cerebral sulci in an area of intracranial mass effect resulting as gyri are squished together, displacing the CSF between them - **[superior cavoatrial junction](https://casestacks.com/terms/superior-cavoatrial-junction)**: The junction between the superior vena cava and the right atrium - **[syrinx](https://casestacks.com/terms/syrinx)**: An abnormal fluid-filled cavity within the spinal cord - **[T2/FLAIR](https://casestacks.com/terms/t2flair)**: On T2-weighted brain MRI sequences, CSF is very hyperintense and gray matter is hyperintense relative to white matter. T2/FLAIR uses inversion recovery to null the signal from CSF; therefore, CSF is very hypointense on T2/FLAIR sequences. - **[T2/STIR](https://casestacks.com/terms/t2stir)**: On T2-weighted spine MRI sequences, both CSF and fat are hyperintense. T2/STIR uses inversion recovery to null the signal from fat; therefore, fat is very hypointense on T2/STIR sequences. - **[trabeculation](https://casestacks.com/terms/trabeculation)**: Irregular bladder wall thickening, often as a result of chronic outlet obstruction - **[transition point](https://casestacks.com/terms/transition-point)**: The location of an abrupt change in the caliber of a bowel loop from normal to abnormal - **[tree-in-bud nodularity](https://casestacks.com/terms/tree-in-bud-nodularity)**: Clustered small nodules along a segment of the bronchial tree - **[uncal herniation](https://casestacks.com/terms/uncal-herniation)**: Abnormal medial and inferior displacement of the medial part of the temporal lobe - **[varices](https://casestacks.com/terms/varices)**: Abnormally dilated and serpentine veins - **[vasospasm](https://casestacks.com/terms/vasospasm)**: Area(s) of arterial narrowing due to muscle constriction in the arterial wall ## Notes for AI crawlers Non-free case write-ups require a paid subscription and are deliberately absent from this index. 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