spect lab Shoot for the Moon. Even if you miss, you ll land among the stars. nuclear medicine services Visit us at :

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1 Scintillations Shoot for the Moon. Even if you miss, you ll land among the stars. solov - PETCT Volume III / Issue I JAN - MAR 2011 spect lab nuclear medicine services Visit us at :

2 Case 33. Von Hippel Lindau syndrome: Contributed by : Dr. F F Wadia, Dr. V Lobo, Dr. R Bhandari, Dr. Shrikant Solav Von Hippel Lindau syndrome is a hereditary autosomal dominant disorder caused by defective tumor suppression gene at 3p25-p26. The gene for Von-Hippel Lindau disease (VHL) is found on chromosome 3, and is inherited in a dominant fashion. The VHL gene is a tumor suppressor gene. This means that its role in a normal cell is to stop uncontrolled growth and proliferation. It is characterized by abnormal growth of blood vessels. It strikes the eyes, central nervous system, kidneys, endocrine glands etc. It predisposes the patient to retinal angiomas, central nervous system hemangioblastoma, renal cell carcinoma, pheochromocytomas, islet cell tumor of the pancreas, endolymphatic sac tumors, renal, pancreatic, epididymal cysts. We present a case of familial Von Hippel Lindau syndrome whose F18 FDG PET CT scan was truly positive for adrenal pheochromocytoma but was falsely negative for renal cell carcinoma. Fig. 1 Fig. 2 Fig. 3 Fig.4

3 A 22 year old gentleman with family history of renal cell carcinoma presented with hypertension. Sonography revealed right suprarenal mass. The echotexture of both the kidneys was normal. The urinary VMA (vanilyl mandelic acid) was elevated. Iodine 131-metaiodobenzyl guanidine (MIBG) scan (not shown here) was normal. Fluorine 18-fluorodeoxyglucose positron emission tomography-computed tomography (F18-FDG PET CT) scan revealed hypermetabolic right adrenal mass suggestive of pheochromocytoma. Fig. 5 cortical or pancreatic lesions. There were no hypermetabolic renal Subsequent high resolution computer tomography of the kidneys revealed multiple hypervascular cortical based lesions in the right kidney. The pancreas was replaced by multiple cysts. Per operative needle aspiration from pancreas did not show malignant cells. Partial nephrectomy was done. Histology of the renal lesion showed clear cell carcinoma. Von Hippel Lindau (VHL) disease was first described at the beginning of the 20th century by Eugen von Hippel and Arvid Lindau.Renal cell carcinoma occurs in 36% of patients of von Hippel Lindau (VHL) disease. Renal cell carcinoma may also be associated with pheochromocytoma as part of the von Hippel Lindau syndrome. Majority of studies have shown limited sensitivity of FDG PET CT in primary evaluation of renal cell carcinoma and high sensitivity to evaluate metastasis and restaging. The overall sensitivity and specificity of FDG PET CT has been shown to be 60% and 100% respectively in renal cell carcinoma. In the presented case FDG PET CT did not show hypermetabolic activity within the renal parenchymal lesions. Fig. 6

4 These were related to clear cell carcinoma on histology. Pheochromocytomas are tumors of sympathetic chromaffin tissue of adrenal medulla. The tumor occurs in 10-20% patients with VHL disease. VHL can be subdivided into type 1 (low risk of phaeochromocytoma) and type 2 (high risk of phaeochromocytoma). Type 1 disease is associated with large deletions and mutations resulting in a truncated VHL protein, thereby conferring a lower risk for phaeochromocytoma. Type 2 is subdivided into type 2A (low risk of RCC), type 2B (high risk of RCC) and type 2C (phaeochromocytoma only). Pheochromocytomas are known to be hypermetabolic on FDG PET CT scan as in the presented case. The pancreatic cysts seen in the presented case were ametabolic. Although different histologic types of cystic pancreatic neoplasms have been reported in the literature, serous cystadenomas, mucinous cystic neoplasms, and intraductal papillary mucinous neoplasms (IPMNs) account for 90% of all primary cystic pancreatic neoplasms. Serous cysadenomas are usually benign and mucin secreting tumors have malignant potential. Cysts in pancreas may be unilocular, multilocular, with or without solid component. Multiple cysts usually follow pancreatitis. VHL disease is also associated with multiple cysts that are usually true epithelial cysts. Other causes of true epithelial cysts being autosomal dominant polycystic kidney disease and cystic fibrosis. Per operative needle aspiration from the pancreatic cysts in the presented case did not reveal malignant cells. Legends: Fig. 1. Maximum intensity projection image ( ) shows avid FDG uptake in the right suprarenal region. Fusion image (Fig 2) shows localization to the right adrenal gland ( ). Another section (Fig 3) shows ametabolic lesion in the lateral cortex of left kidney ( ). The entire pancreas (Fig 4) shows ametabolic cystic degeneration ( ).Fig. 5. Three dimensional reconstructed image (A) shows lesions in the left kidney ( ), these were hypervascular (Fig 6) in the arterial phase ( ). Fig. 7. Histology revealed clear cell carcinoma of the kidney. Fig. 7

5 Case 34. Myocardial tuberculosis presenting as ventricular tachycardia. Contributed by : Dr. Rajesh Dhopeshwarkar, Dr. Sujit Joshi, Dr. Ritu Bhandari, Dr. Shrikant Solav Fig. 1 Perfusion metabolism mismatch is typically seen in hibernating myocardium. However focal inflammation in the myocardium will be hypermetabolic on fasting cardiac FDG PET study. Further such a lesion may also show perfusion abnormality secondary to myocardial infiltration as in the presented case giving an appearance of perfusion-metabolism mismatch. Ventricular tachycardia is most commonly associated with ischemic heart disease. Other causes of tachyarrhythmia include pre excitation syndrome, electrolyte imbalance, myocarditis, cardiomyopathy, valvular heart disease. Infiltration of the myocardium by granulomatous disorders comprises a small percentage of this presentation that includes sarcoidosis, tuberculosis, Aschoff's nodules of rheumatic fever.

6 A 55 year old gentleman presented with chest discomfort and had recurrent episodes of hemodynamically stable monomorphic VT of two morphologies. These were reverted with DC cardioversion. His ECG was normal, Troponin T was negative. Coronary angiogram done elsewhere showed mild mid LAD disease. Echocardiography done showed normal left ventricular function with small inferobasal hypokinesia. Electrophysiologic study showed easily inducible monomorphic VT of two morphologies at the rates of 160/min or 200/min. (Fig 1) Cardiac MRI (magnetic resonance imaging: not shown here) showed infiltration in the inferolateral myocardium. Whole body F18-FDG PET CT (fluorodeoxyglucose positron emission tomography computed tomography) was performed using eight millicurie (296 MBq) radiotracer activity administered intravenously on six hours fasting stomach. Images were acquired at 60 minutes on dedicated Biograph duo LSO based Siemens Medical PET CT system. It showed hypermetabolic right supraclavicular and mediastinal lymphadenopathy with a standardized uptake value of 6.8 and 8.35 respectively. (Fig 2) The multiple mediastinal lymph nodes were in close relation to the myocardium. Fig. 2 In addition, there was a hypermetabolic focus in inferobasal segment of the myocardium.myocardial perfusion scintigraphy was performed with seven millicurie (259 MBq) of Technetium-99m-Sestamibi administered intravenously at rest on the next day. Images were acquired on Symbia E Siemens medical gamma camera system using low energy high resolution collimator. It revealed perfusion defect in the basal inferolateral myocardium. The same region was hypermetabolic on FDG scan giving perfusion-metabolism mismatch pattern.

7 Fig. 3 (Fig 3)The heart uses a wide variety of substrates for its metabolism ranging from free fatty acids, glucose, amino acid, lactate, pyruvate, ketones bodies. F18-FDG is used to measure myocardial glucose uptake. Iodine-123- Beta-methyl iodine phenylpentadecanoic acid (BMIPP) is a structurally modified fatty acid, which is used to trace uptake of fatty acids in the myocardium. C-11-Acetate immediately enters the tricarboxylic-acid (TCA) cycle. Metabolism of C-11-acetate is dependent solely on the tricarboxylic acid cycle activity. As the TCA-cycle activity is directly coupled to myocardial oxygen consumption, clearance rates of C11-acetate are used to assess regional myocardial consumption of oxygen. C-11-acetate imaging has been validated for normal subjects and patients with CAD and appears to be as effective as use of FDG for assessing viability. Fig. 4A Fig. 4B

8 Under normal conditions, free fatty acids and glucose are the major sources of energy. In contrast, in ischemia with less than normal delivery of oxygen, oxidative metabolism of free fatty acids is decreased. Thus, exogenous glucose becomes the preferred substrate and the production of energy mainly depends on anaerobic glycolysis. Thus, there is preferential utilization of glucose in ischemic myocardium that can be imaged with F18-FDG PET scan. F-18- fluorodeoxyglucose is a glucose analogue and the initial uptake of F-18 fluorodeoxyglucose is almost identical to that of glucose. After uptake, F-18-fluorodeoxyglucose undergoes phosphorylation, but unlike glucose-6-phosphate, FDG-6- phosphatase does not undergo further metabolism and remains trapped in the myocardium. In fasting state the myocardium preferentially uses free fatty acid for its metabolism. In post prandial state there occurs a shift towards glucose. Thus, in evaluation of ischemic heart disease with left ventricular dysfunction, the test is performed one hour post glucose challenge to encourage myocardial glucose uptake. However, in state of prolonged overnight fasting there is little /variable uptake of FDG in the myocardium. In the case presented here, there was focal segmental uptake of FDG in fasting state, corresponding to the region of perfusion defect as demonstrated on myocardial perfusion scan. Such an abnormality favors an inflammatory/ infective lesion. There was substantial evidence to support this in view of intensely hypermetabolic mediastinal lymphadenopathy abutting the myocardium. Perfusion metabolism mismatch has been reported previously in cardiac sarcoidosis. However, such a pattern has not been reported in myocardial tuberculosis. Legends: Fig 1. Electrocardiogram showing monomorphic ventricular tachycardia. Fig 2. Maximum intensity projection image from Fluorine 18-fluorodeoxyglucose positron emission tomography computed tomography (F18-FDG PET CT) scan demonstrates hypermetabolic right supraclavicular ( ) and conglomerate mediastinal () lymphadenopathy. The apicoinferior segment of the myocardium (<) also shows mildly increased metabolism as compared to the surrounding myocardium. Fig 3. Myocardial perfusion study performed with Techentium-99m-Sestamibi shows perfusion defect in the inferolateral segment (Fig 3A). Imaging done on another day in fasting state (without prior glucose load) using F18- fluorodeoxyglucose shows hypermetabolic inferolateral segment (Fig 3B) giving the appearance of perfusionmetabolism mismatch. Fig 4. Histology of supraclavicular lymph node shows caseating granuloma ( Fig 4 A and B) confirming the diagnosis of tuberculosis. Whole Body PET-CT Scan in Just Rs /- Complimentary copy (Not for Sale) Address : SPECT LAB NUCLEAR MEDICINE SERVICES K-2/1, Erandawana Co-op.Society,Opp. Dinanath Mangeshkar Hospital,Near Mehendale Garage, Pune (INDIA).Phones: (020) / / / Mobile Nos.: / / Visit us at : solav@vsnl.com