General Nuclear Medicine Part 2

For Medical StudentsFor Medical Students

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Liver scanHepatobiliary scintigraphyGI Tract• GI bleeding study• Meckel’s diverticulum• Gastroesophageal studiesBrain scanNuclear cardiology

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The biggest organ, 1500 gAnatomy: 4 parts- Right, Left, Caudate, and Quadrate lobesHistology:

Hepatocytes or polygonal cellsRE cells (Kupffer’s cells)

phagocytosisBlood Supply:

Portal vein 75 %Hepatic artery 25 %

THE LIVER

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Tracer: 99mTc-sulfer colloid/ phytateRoute : IV injectionMechanism : Phagocytosis by RE cells (liver,spl,BM)Visualization : Liver and SpleenTechnique:

Patient preparation : noneImaging : 15-20 min. Pi.Static 6 views ; Ant, Post, RL, LL, RAO, LAOSPECT images

Diagnosis : Diffuse & focal lesions focal defect(s) -nonspecific (abscess, metastasis, cyst etc.)

LIVER-SPLEEN SCAN(Routine Liver Scan)

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Normal Liver Scan Abnormal Liver Scan:Multiple focal defects

LIVER-SPLEEN SCAN

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Tc-99m RBC LIVER SCAN

Aim: hepatic hemangioma [hemangioma is the most common benign liver tumor ]U/S: Typical hyperechoic mass in 60%CT scan: Classical findings in 50-75%MRI has an accuracy of between 90-95%Tc-RBC imaging is the most specific test for Dxcavernous hemangioma. (Sens 90% for lesions >1.5-2 cm; Spec approaches 100%; Acc 90-95%).With SPECT lesions down to about 1 cm in size can be detected [SPECT sensitivity by size: 1.5 cm (100%), 1 cm (65%), 0.5 cm (20%)].

Ref: www.auntminnie.com

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Vascular Study SPECT

HEPATIC HEMANGIOMA

Imaging: Flow, Static, Delayed***Positive : activity with time hot lesion

3-D image

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HEPATOBILIARY IMAGING

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Tracers : 99mTc-IDA derivatives (Tc-99m DISIDA, Mebrofenin)Route : IV injectionMechnism : Carrier-mediated, non sodium dependent organic anion transport processTechnique : - Fasting 4-6 hr

- Dynamic study for at least 1 hour +/-delayed imaging

Visualization : Liver and biliary system including gallbladder until excretion into small bowel (normal = within 1 hour)

HEPATOBILIARY IMAGING

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Gallbladder disease :Acute cholecystitis*

• Non-visualization of the GB after 4 hrs

• sen > 95% , spec > 98%Biliary tract obstruction

DDx biliary atresia vsneonatal hepatitis

Biliary leakage

HEPATOBILIARY IMAGING: INDICATIONS

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Tc-99m DISIDA

Visualization :Liver and biliary system including

Right & left hepatic ductsCommon hepatic ductCommon bile ductGallbladder Until excreted into small bowel

Within 1 hour

NORMAL HEPATOBILIARY IMAGING

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DISIDA Scan-Dynamic Study

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Is it normal study ?

Acute cholecytitisNo visualization of GB

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Acute cholecystitisSevere chronic cholecystitisProlonged fastingIntercurrent severe illnessAcute pancreatitisSevere liver diseaseS/P cholecystectomy

DDx Nonvisualized GB

Ac chole wo gallstone !

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False-negative Test

It is found less than 5% of patients, and may be associated with:Incomplete cystic duct obstruction Acalculous cholecystitisAccessory cystic duct Duodenal diverticulum simulating GB activity

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DDx biliary atresia & neonatal jaundiceSen 97-100%, spec 82-94%, and accuracy of 91%Findings of BA:

Good hepatic uptakeNo visualization of GBNon-visualization of the biliary tree and bowel

Findings of neonatal hepatitisVariable hepatic uptake // Fn.Visualization of GBPresence of radioactivity excretion into small bowel

NEONATAL JAUNDICE

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BILIARY ATRESIA

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HB Scintigraphy in BA

Normal uptake and excretion of the tracer in a jaundiced neonate excludes the diagnosis of biliary atresia.Children should be studied before age of 3 months Beyond 3 months of age, the prolonged obstruction will begin to affect liver function and hepatic extraction of the tracer will deteriorate making differentiation from hepatitis more difficult.

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GI BLEEDING STUDYBleeding from lower GI tractActive bleeding is necessary for positive imaging.Preparation: NPOPosition: Supine- anterior abdomenTc99m-SC or Tc99m-RBC* (intermittent)Imaging:

Flow 1 minDynamic imaging for 1-2 hr with additional delayed images as required.

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Extravasation of the tracer into bowel lumenFocal area of increased activity, move // bowel movement

Pattern depends on site of bleeding & bowel peristalsis

•Tc-99m RBC

•Hepatic flexure

GI BLEEDING

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GI BLEEDING

ST, Date: 4-6-07GIV002-07

SA-ING THONGKAM

CINE MODE

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More sensitiveLess specificLess anatomical detailsLess invasiveLower riskSimpler

Less sensitiveMore specific-causeBetter anatomical detailsMore invasiveHigher riskNeeds more skills

Tc-99m RBC Scan vs Angiography

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Remnant of omphalomesenteric ductGastric mucosal lining*Common cause of lower GI bleeding in small childrenImaging:

Principal: Localization of ectopic gastric mucosaPatient preparation: NPO 4 hrRadiopharm: Tc-99m pertechnetate IV.Sequential imaging for 1-2 hr.Positive findings: Focal hot spot (RLQ) // stomach activitySen 85%, spec 95%

MECKEL’S DIVERTICULUM

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MECKEL’S DIVERTICULUM

Bladder

Stomach

M

Stomach

U. Bladder

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GASTRO-ESOPHAGEAL STUDY

Esophageal transit study

Gastroesophageal reflux study (milk scan)

Gastric emptying study

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Indication: To detect GE reflux:-regurgitation of gastric contents esophagusTracers : Tc-99m phytate, Tc-99m SC 300 uCiTechnique :

NPO, oral tracer adm. within 30 sSupine imaging over EG junctionDynamic imaging for >10-20min. Views: anterior ( & posterior)

Positive : Activity from the stomach esophagus [N < 3 %, Abn >4 %]

GE REFLUX STUDY(MILK SCAN)

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GE Reflux (Milk Scan)Rdn study provides higher sensitivity but less anatomical details than esophagogramSensitivity and specificity for detecting GER are 75%-100% and 93%.

Ref: J Nucl Med 2004; Mariani G, et al. Radionuclide gastroesophageal motor studies. 45: 1004-1028

Ravelli, A. M. et al. Chest 2006;130:1520-1526

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1. Conventional Rdn. brain imaging

Tracers: Tc- 99m pertechnetate, Tc-99m DTPA*, Tc-99m glucoheptonateHydrophilic tracers:cannot pass normal BBB.(Normally no tracer accumulation in the brain tissue)Disrupted BBB abnormal uptake

2. Cerebral perfusion SPECT

Radiopharm.: I-123 IMP ,Tc-99m HMPAO*, Tc-99m ECDLipophilic tracers, can pass intact BBB.Uptake: proportion to regional cerebral blood flowIndications: CVD,epilepsy, dementias,parkinsonism, ect.

BRAIN IMAGING

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Picker-Prism

SPECT BRAIN IMAGING

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Brain death: Tc-99m DTPA, Tc-99m HMPAO, TC-99M ECD

Cerebrovascular diseaseFocal seizureDementiaPsychitric disordersOthers

APPLICATIONS

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www.derriford.co.uk/nucmed

NORMAL BRAIN SPECT

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Flow study : no appreciable intracerebral blood flow in either the internal carotid or posterior cerebral circulations.Planar static images: “Hot nose” sign due to shunting of flow from int carotid to ext carotid system, which supplies face & scalp.Tc-99m HMPAO SPECT: No cerebral uptake

Www.cseserv.engr.scu.edu/StudentWebPages/DZepeda/brainscin.html

BRAIN DEATH

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SPECT

Static

FlowTc-99m HMPAO

BRAIN DEATH

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Stroke at left temporoparietal region


3D

STROKE

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FOCAL SEIZURE

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SPECT


ALZHIEMER’S DISEASE

Decreased perfusion at bilateral parieto-temporal regions

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PET

ALZHIEMER’S DISEASE

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A labeled amino acid called F-DOPA is used with PET to see if your brain has a deficiency in dopamine synthesis.

Striatral uptake PET

PARKINSON DISEASE

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NUCLEAR CARDIOLOGY

Radionuclide angiocardiography *

Equilibrium gated blood pool study (GBP or MUGA study)*

Myocardial infarct imaging

Myocardial perfusion imaging**

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RADIONUCLIDE ANGIOCARDIOGRAPHY

First pass Rdn. angiocardiography

Equilibrium gated blood pool study (MUGA study)**

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FIRST PASS RDN.VENTRICULOGRAPHY

Tracers: Tc-99m agentsIndications:

Diagnosis of SVC obstruction (first pass)Calculation of ejection fraction: RVEF, LVEF

• EF = (ED-ES)/ED

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Equilibrium MUGA

Tracer: Tc-99m RBCFindings

Cardiac shape and sizeWall motion*: global, regionalStroke volume (ED counts - ES counts)Ejection fraction (EF): LV, RV

• EF = (ED counts - ES counts) / (ED counts)• Normal LVEF is typically 60-70%. (LVEF < 50% is definitely abnormal

• RVEF should > 41%.

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Equilibrium MUGA

Findings (cont.)LV outputs

• Phase analysis: dyskinesis eg. aneurysm• Amplitude analysis

Diastolic ventricular functionIndications

DDx CAD from cardiomyopathyPlan Rx valvular heart diseaseMonitoring cardiac toxicity from chemotherapeutic agent eg. adriamycin

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Equilibrium MUGA

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MYOCARDIAL INFARCT IMAGING

Tracer: Tc-99m pyrophosphate (PYP)Mechanism: Bind to calcium in AMI Indication:

Dx AMI

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MYOCARDIAL PERFUSION IMAGING

Tracers:Thallium-201 (Tl-201)Tc-99m MIBI (Cardiolyte)Tc-99m tetrofosmin

Principle: Myocardial perfusion of LV*Technique

Acquire rest & stress imagesStress: exercise or pharmacological tests

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EXERCISE STRESS TEST

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PHARMACOLOGICAL STRESS TEST

Dipyridamole (Persantin)

Dobutamine

Adenosine

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MYOCARDIAL PERFUSION IMAGING

Imaging techniquesPlanar images: 2DSPECT images*: 3D

• short axis,• long axis-LH, LV

Gated SPECT: contractile function (LVEF)Interpretation

Compare between rest & stress images• Fixed perfusion defect: infarct• Transient perfusion defect: ischemia

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Heart Orientation & Heart Plane

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Planes & SPECT Images

LAT

SEP

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MYOCARDIAL PERFUSION IMAGING:INDICATIONS

Screening - preoperative evaluationDetection of CADEvaluation of extent & severityAssess myocardial viabilityPlan of Rx: revascularization vs medical RxPost MI evaluationPrognosis of CAD patients Assess outcome & efficacy of Rx (F/U)Dx restenosis after revascularization

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Normal Tc-99m MIBI MPI

STRESS

REST

STRESS

REST

SHORT AXIS

LONG HORIZONTAL AXIS

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Normal Myocardial Perfusion Scintigraphy

Polar Map

Bull’s Eye

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Fixed Defect:Inferolateral Wall MI

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Reversible Defect: Anteroseptal Wall Ischemia

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MPI: Summary

Myocardial perfusion study is an noninvasive nuclear medicine study that evaluate regional myocardial perfusion as well as LV contraction-EF and regional wall motion in a single setting.

Education

General Nuclear Medicine Part 2