Lung carcinoma

Brain tumors,  especially necrosis vs. recurrence

Melanoma  

Soft tissue sarcomas

Colorectal carcinoma

Head and neck carcinomas

Endocrine/ neuroendocrine neoplasms

Breast carcinoma

Ovarian carcinoma

Genito-urinary tumors

Lymphoma

Pancreatic carcinoma

Cardiology Applications

• Tissue viability Coronary Artery Disease (Future - Non-ischemic cardiomyopathies : sympathetic innervation studies)

• Flow tracer - N-13 Ammonia

• Metabolic tracer - F-18-FDG
  

Neurology Applications

• Tumor recurrence and viability vs. post-surgical, post-chemo, post-Radiotherapy changes of tissue necrosis, scar, and gliosis

• Brain Tumors

  • Post-therapy changes causing difficulty in contrast enhancement properties of tissue on CT and MRI

  • Limited information on tumor grade with anatomical imaging techniques

  • PET is helpful in guiding biopsies to recurrent or active tumor sites

Neuropsychiatric Applications

• Epilepsy

  • Refractory seizures - 30-60 %

  • Require surgery for control

  • Complex partial seizures or Temporal Lobe Epilepsy

  • Accurate and precise localization and lateralization - 70 %

  • Metabolic changes identify/precede/extend beyond anatomical changes

  • EEG ( surface ) 60-70 % localization

  • MRI to identify Mesial Temporal Sclerosis

  • Depth electrodes - invasive, surgical morbidity, expensive, limited expertise

  • PET - integral part of non-invasive pre-operative work-up of TLE patients

  • MRI for MTS - volumetric analysis, reduced hippocampal volume High signal on T2

  • Sensitivity of MRI > 50 % no abnormalities

  • Specificity of MRI

  • CT scan - 17-20 % detection

  • PET in Epilepsy

    • Inter-ictal PET - better spatial resolution compared to inter-ictal Tc-99m SPECT

    • Unilateral Temporal lobe hypometabolism with PET predicts good outcome from surgery compared to pts w/ no abnormality or bilateral abnormality.

    • High sensitivity of PET

    • 70 % - discrete hypometabolism

    • Strong correlation - EEG & PET

• Dementia

  • PET in Dementia

    • Non-invasive imaging techniques

    • Aiding clinical diagnosis

    • Assess prognosis

    • Early planning of future care

    • Therapeutic options/ management decisions

    • Differential Diagnosis of Dementias

    • More sensitive than clinical/ anatomical assessment

• Alzheimer's Disease

  • Early - hippocampal hypometabolism

  • Later - bilateral decreased uptake in parietal, temporo-parietal, and later, frontal cortices

  • Sparing of basal ganglia, thalami, sensori-motor cortex strip, cerebellum, and visual cortex

  • Increasing hypometabolism correlates with greater clinical severity of dementia

  • Metabolic changes precede cognitive defects or clinical criteria for diagnosis

  • PET enables quantitative data, allowing more reliable differentiation from normals and other dementias

  • Variety of activation tasks in Alzheimer’s : enhancement of discriminative power

• Other Dementing Diseases

  • Vascular dementias / multi-infarct dementia - subclinical, small cortical and subcortical infarcts pattern of abnormalities - focal defects which are scattered in the cortex and subcortical region

  • Pick’s Disease - symmetric reduction in frontal and anterior temporal lobes

  • Parkinson’s Disease - pts with progressive supra-nuclear palsy show mainly focal and subcortical hypometabolism

  • Huntington’s Disease - caudate nuclei

  • HIV Dementia - cerebral lymphomas vs. / Toxoplasmosis / TB

Lung Cancer

• Benign vs Malignant Solitary Pulmonary Nodule

• Pre-operative staging for mediastinal or distant metastasis

  • 1/3 NSC operable by CT criteria have unsuspected lesions identified on PET

  • 18 % management altered to non-surgical regime (Clinical Radiology ,1996, 51 ,603-613 Cook et al)

• 20-30% lung masses found "resectable" by current criteria and imaging techniques

• 5-7% unresectable at surgery

• 14% die within 1 yr of "curative surgery"

• Multi-Center Trial on NSC lung Cancer

  • CT is 52 % sensitive and 69 % specific

  • MRI is 48 % sensitive and 64 % specific

• PET in Lung Cancer

  • Sensitivity 82-85%

  • Specificity 80-93%

  • Accuracy 80-90%

  • Positive PV 75-85%

  • Negative PV 87-93%

• CT in Lung Cancer

  • Sensitivity 65%

  • Specificity 50-69%

  • Accuracy 52- 68%

  • Positive PV 44-50%

  • Negative PV 64-81%

Malignant Melanoma

• Most aggressive, high mortality, hematogenous spread, early nodal mets

• LN surgery controversial- 20-40% have metastasis at surgery

• Often micro-metastasis, all (-) on CT/ MRI

• PET ( ve) lesions Biopsy ( ve) 96 %

• Pre-operative staging

• Recurrence