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PERFUSION IMAGING ---BASICS

-------Perfusion magnetic resonance (MR) imaging techniques are widely used in the clinical work-up of brain tumors because of their ability to help quantify tumor microvessel proliferation and permeability and thus to measure changes associated with neoangiogenesis, which correlate with tumor malignancy. 

-----Dynamic susceptibility contrast (DSC) MR imaging  has been extensively explored for glioma grading , for prognostic assessment , and for differentiating between recurrent tumor and posttreatment changes . 

-----Dynamic contrast material–enhanced (DCE) MR imaging has been recently introduced in the preoperative assessment and follow-up of brain tumors. 

------The DCE signal intensity– time curve reflects a combination of tissue perfusion, microvessel permeability, and extravascular-extracellular space , thus allowing for a multiparametric characterization of tumor microvasculature. 

------The advantages of DCE over DSC are fewer susceptibility artifacts and the quantification of blood-brain barrier (BBB) integrity; indeed, the main interest for DCEderived metrics was initially focused on the volume transfer constant (Ktrans), a permeability marker correlating with BBB disruption and malignancy . 



----The advantage of DSC over DCE is better temporal resolution, allowing better estimation of blood volume. 

PRECISION MEDICINE/RADIOMICS/RADIOGENOMICS

----Precision medicine is medicine optimized to the genotypic and phenotypic characteristics of an individual and, when present, his or her disease. It has a host of targets, including genes and their transcripts, proteins, and metabolites. 

----Studying precision medicine involves a systems biology approach that integrates mathematical modeling and biology genomics, transcriptomics, proteomics, and metabolomics. 

----Moreover, precision medicine must consider not only the relatively static genetic codes of individuals, but also the dynamic and heterogeneous genetic codes of cancers. Thus, precision medicine relies not only on discovering identifiable targets for treatment and surveillance modification, but also on reliable, noninvasive methods of identifying changes in these targets over time. 

---Imaging via radiomics and radiogenomics is poised for a central role. 

-----Radiomics, which extracts large volumes of quantitative data from digital images and amalgamates these together with clinical and patient data into searchable shared databases, potentiates radiogenomics, which is the combination of genetic and radiomic data.

----- Radiogenomics may provide voxel-by-voxel genetic information for a complete, heterogeneous tumor or, in the setting of metastatic disease, set of tumors and thereby guide tailored therapy.

 -----Radiogenomics may also quantify lesion characteristics, to better differentiate between benign and malignant entities, and patient characteristics, to better stratify patients according to risk for disease, thereby allowing for more precise imaging and screening. 
REF --RADIOLOGY

TELE -BILI-PAQUE

Q1..All are true regarding Telepaque and Bilipaque except

a.bilopaque is better choice than Telepaque in patients with enterrupted enterohepatic circulation

b.Telepaque is more lipid –soluble than Bilopaque

c.peak contrast concentration occurs after approx.10 hrs after Bilopaque  ingestion

d.the usual dose of Telepaque is 6 tabs after evening meal

e.patients must take fat after ingetion of Telepaque

ANS.---e

Patients must not take anything except water after ingestion of Telepaque

Q2..All are causes of non visualisation of  the gall bladder during oral cholecystography except

a.esophageal /gastric/small intestinal obstruction

b.Crohn disease

c.disruption of renal circulation

d.hepatic dysfunction

e.acute/chronic cholecystitis

ANS.---c

Disruption of entero-hepatic circulation is one of the cause of non –visualisation of gall bladder