Objetivo: describir los hallazgos de imagen clave en los estudios de RM estructural de las demen- cias de origen neurodegenerativo más frecuentes: enfermedad de Alzheimer, demencia vascular, demencia de cuerpos de Lewy, variantes de la demencia frontotemporal, parálisis supranu- clear progresiva, variantes de la atrofia multisistémica, parkinson-demencia y degeneración corticobasal.
Conclusión: El papel de la resonancia magnética hoy en día ya no está limitado a excluir causas subyacentes de deterioro cognitivo, sino que puede mostrar patrones de atrofia y otros datos con un alto valor predictivo para determinadas demencias que, aunque no son específicos ni únicos de cada patología, pueden ayudar a confirmar una sospecha diagnóstica o a identificar inicios tempranos de determinados procesos. Por ello es importante que los radiólogos conozcan los hallazgos típicos de las demencias más frecuentes.

Palabras clave: Resonancia magnética; Atrofia; Demencia; Enfermedad de Alzheimer; Parálisis supranuclear progresiva; Demencia vascular; Atrofia multisistémica; Enfermedad de Parkinson; Demencia frontotemporal

Background:
Inaugural consensus statements were developed and endorsed by the American College of Radiology (ACR) and the National Kidney Foundation to improve and standardize the care of patients with kidney disease who have indication(s) to receive ACRdesignated group II or group III intravenous gadolinium-based contrast media (GBCM). The risk of nephrogenic systemic fibrosis (NSF) from group II GBCM in patients with advanced kidney disease is thought to be very low (zero events following 4931 administrations to patients with estimated glomerular filtration rate [eGFR] ,30 mL/min per 1.73 m2 ; upper bounds of the 95% confidence intervals: 0.07% overall, 0.2% for stage 5D chronic kidney disease [CKD], 0.5% for stage 5 CKD and no dialysis). No unconfounded cases of NSF have been reported for the only available group III GBCM (gadoxetate disodium). Depending on the clinical indication, the potential harms of delaying or withholding group II or group III GBCM for an MRI in a patient with acute kidney injury or eGFR less than 30 mL/min per 1.73 m2 should be balanced against and may outweigh the risk of NSF. Dialysis initiation or alteration is likely unnecessary based on group II or group III GBCM administration. This article is a simultaneous joint publication in Radiology and Kidney Medicine. The articles are identical except for stylistic changes in keeping with each journal’s style. Either version may be used in citing this article.

Results: A total of 3987 asymptomatic adult patients (mean age, 64 years 6 9 [standard deviation]; 2567 women) underwent mt-sDNA screening and 9656 patients (mean age, 57 years 6 8; 5200 women) underwent CT colonography. Test-positive rates for mt-sDNA and for 6-mm- and 10-mm-threshold CT colonography were 15.2%, 16.4%, and 6.7%, respectively. Optical colonoscopy follow-up rates for positive results of mt-sDNA and 6-mm- and 10-mm-threshold CT colonography were 13.1%, 12.3%, and 5.9%, respectively. Positive predictive values (PPVs) for any neoplasm 6 mm or greater, advanced neoplasia, and CRC for mt-sDNA were 54.2%, 22.7%, and 1.9% respectively; for 6-mm-threshold CT colonography, PPVs were 76.8%, 44.3%, and 2.7%; for 10-mm-threshold CT colonography, PPVs were 84.5%, 75.2%, and 5.2%, respectively (P , .001 for mt-sDNA vs CT colonography for all except 6-mm CRC at CT colonography). For mt-sDNA versus 6-mm-threshold CT colonography, overall detection rates for advanced neoplasia were 2.7% and 5.0%, respectively (P , .001); corresponding detection rates for CRC were 0.23% and 0.31%, respectively (P = .43).

Conclusion:

The detection rates of advanced neoplasia at CT colonography screening were greater than those of multitarget stool DNA. Detection rates were similar for colorectal cancer.