Narendra Nair

Micronuclei frequency in peripheral blood lymphocytes of thyroid cancer patients after radioiodine therapy and its relationship with metastasis.

In most cancers peripheral blood lymphocytes exhibit DNA damage. In the case of thyroid cancer the micronucleus (MN) assay has been used to assess DNA damage before and after exposure to iodine-131 ((131)I). The aim of our study was to use this method to assess DNA damage in peripheral blood lymphocytes of thyroid cancer patients and search for its relationship with metastasis as well as (131)I exposure. A significant increase in micronuclei frequency was observed in peripheral blood lymphocytes of 54 thyroid cancer patients in comparison to 38 controls (p=0.000). Further analysis revealed significant elevation in micronuclei index from 48.5 MN/1000 BN cells (range: 25.1-111.2, n=25) in patients without metastasis to 68.1 MN/1000 BN cells (range: 26.2-135.5, n=29, p=0.001) in group of patients with metastasis to one or more sites. There was no clear correlation between the micronuclei frequency and the therapeutic (131)I dose ranging from 0.41 to 31.5 GBq with the exposure interval of <1 to 126 months. In addition, age and sex did not show any influence on micronuclei frequency in either patients or control population. These findings are indicative of increased basal DNA damage in thyroid cancer patients before treatment. Radioiodine treatment did not increase DNA damage measured by the micronuclei frequency for the interval between the last radioiodine dose administered and analysis of blood sample. However a significant increase of peripheral blood lymphocytes micronuclei was observed in thyroid cancer patients with metastasis.

Potential clinical role of FDG-PET in detecting sarcomatous transformation in von Recklinghausen's Disease: a case study and review of the literature

BackgroundThe diagnosis of sarcomatous transformation of plexiform neurofibromas in Neurofibromatosis-1 (NF 1) is a clinical and radiological challenge. Considerable overlap exists in the clinical and the radiological characteristics between the benign enlarging neurofibromas and their counterparts undergoing malignant changes. Surgical biopsy to rule out suspicious malignant transformation is often a problem in deep seated lesions.MethodsWe, in this paper, explore the clinical utility of FDG-PET in detecting and assessing this life threatening complication of neurofibromas. A case is described with FDG-PET and MRI documentation of such transformation and subsequent histopathological correlation. The case upholds the potential advantages of a FDG-PET over the conventional imaging modalities. A review of the existing literature is also carried out; a total of four published reports on this issue were identified in English literature by searches of Pubmed.Results and conclusionFDG-PET appeared a reliable as well as sensitive noninvasive technique that might minimize unnecessary deep surgical biopsy to rule out malignant transformation in cases of NF-1 with features of enlargement of a preexisting peripheral nerve sheath tumour, pain or neurodeficit.

Are the Effects of Cannabis Dependence on Glucose Metabolism Similar to Schizophrenia? an FDG PET Understanding

Background: Cannabis has been associated with transient psychotic states; however, the causal relationship between cannabis and schizophrenia continues to remain a matter of debate. Epidemiological and some biological studies hint at cannabis being an independent risk factor for schizophrenia; this has not been definitively proved. Aims: We aimed to understand the patterns of glucose uptake in important brain regions among individuals with cannabis dependence and schizophrenia. Furthermore, we compared the interregional metabolic rates in pertinent neural circuits among individuals with cannabis dependence, schizophrenia and normal controls. Setting and Design: This is a case-control cross-sectional study that was carried out by a general psychiatry department in collaboration with a nuclear diagnosis unit. Materials and Methods: Male volunteers with cannabis dependence, schizophrenia and normal controls underwent FDG PET scanning. Glucose uptakes in pre-selected regions of interest were compared using MANOVA. Finally, Chow tests were used to compare interregional metabolic relationships in the mesocortical and cortical-subcortical-cerebellum circuits. Results: Significant differences (P<0.05) were noted among individuals with cannabis dependence and schizophrenia in the medial and lateral temporal regions. When the neural circuits were compared, significant interregional differences (P<0.05) were noted between individuals with cannabis dependence and normal controls. However, among individuals with cannabis dependence and schizophrenia, no significant differences (P>0.05) were noted in these patterns. Conclusions: Our findings suggest that cannabis dependence can alter interregional relationships in a manner similar to schizophrenia. This indicates that cannabis could potentially play a role in the development of psychosis by altering neural circuits.

18F-FDG uptake in bilateral adrenal hyperplasia causing Cushing’s syndrome

Anecdotal case reports have contributed significantly to the continuously accruing literature regarding non-specific FDG accumulation in a wide spectrum of anatomical variants and physiological processes as well as several benign pathologies. It is essential to recognise such accumulation in order to avoid diagnostic errors. Here we present a hitherto unreported case of FDG hypermetabolism in bilateral adrenal hyperplasia causing Cushing’s syndrome. A 19-year-old male, with a prior history of Cushing’s syndrome secondary to ectopic ACTH secretion by a thymic carcinoid (which was treated with thymectomy and postoperative radiotherapy), had recurrence of symptoms of Cushing’s syndrome 2 years after surgery and was referred for FDG PET to rule out any metastatic focus secreting ectopic ACTH. The baseline PET scan (a) demonstrated two foci of FDG hypermetabolism around the superior pole of both kidneys. Furosemide was administered to eliminate FDG activity from the renal pelvicalyceal system. Thereafter the uptake at the “upper poles” of the kidneys remained unchanged (b), indicating the uptake to be in both adrenals. Bilateral adrenal hyperplasia was considered the most probable cause of the Cushing’s syndrome, and this was proven by CT scan. Plain and contrast-enhanced CT (c, d) showed bilateral bulky adrenals with thickening of the limbs. The right adrenal measured: right limb 1.5×0.5 cm and left limb 2×0.5 cm. The left adrenal measured left limb 1.5×0.5 cm and right limb 2×1 cm. Both the adrenals showed homogeneous enhancement in the postcontrast scan. There was no evidence of calcification or necrosis.

Regional brain metabolism in schizophrenia: An FDG-PET study.

Background: Recent technological advances have established beyond any doubt the biological nature of schizophrenia. Functional neuroimaging using FDG-PET forms an important technique in understanding the biological underpinnings of psychopathology of schizophrenia. Methods: Eighteen male patients diagnosed as having schizophrenia and having active psychosis as determined by PANSS were subjected to FDG-PET scanning under resting conditions. The glucose uptake in selected regions of interest was studied across the spectrum of schizophrenia. Results: Chronicity and severity of illness did not influence cerebral glucose metabolism. Participants with negative schizophrenia had significantly decreased metabolism in all regions of the brain as compared to the positive type. The positive syndrome of schizophrenia was associated with significantly increased glucose metabolism in the medial temporal regions, basal ganglia and left thalamic regions. Hypometabolism was also noted in the cerebellum. Conclusion: While a number of brain areas can be identified as potential causative regions and hypotheses regarding putative mechanisms can be formed, the considerable heterogeneity of schizophrenia poses a great challenge in the precise delineation of the disease process.

Cannabis dependence: Effects of cannabis consumption on inter-regional cerebral metabolic relationships in an Indian population

Background: The effects of cannabis consumption on neurophysiological function have been a matter of considerable debate. With the legalization of medical marijuana, understanding the consequences of cannabis dependence has become extremely important. Aim: We attempted to understand the influence of cannabis on cerebral glucose metabolism in certain predetermined regions of interest (ROIs). Furthermore, we also explored inter-regional metabolic relationships between ROIs forming the “addiction” and “cognitive dysmetria” circuit. Materials and Methods: 2-fluoro, 2-deoxy-glucose positron emission tomography (FDG PET) scans were carried out in 16 male patients (age: 25.3±10.38 years) with cannabis dependence, 8–12 hours after the last cannabis consumption. Resting glucose uptake in 14 pre-determined ROIs was compared with glucose uptake in 16 non-drug using volunteers (age: 29.2±8.39 years). Results: The two groups differed in their lateral and medial temporal glucose uptakes by approximately 16–24%. The relationships between inter-regional glucose uptakes in the two circuits were compared using the Chow Test. Significant differences in inter-regional correlations in the medial temporo–frontal and parieto–thalamic were noted between the two groups. Conclusion: The altered metabolic relationships among various brain regions can have potentially important implications for understanding cannabis dependence and cannabis-induced psychopathology.

Regional brain metabolism in schizophrenia: The influence of antipsychotics

BACKGROUND Schizophrenia has been associated with a plethora of metabolic changes in the brain that vary with duration and type of psychoses. Additionally, it has been observed that antipsychotics can further alter cerebral glucose metabolism. These changes resulting from antipsychotics have been postulated to be reflective of the duration and mechanism of action of the medication. AIMS We aimed to examine the influence of antipsychotics on brain metabolism in individuals with schizophrenia in a naturalistic setting. SETTINGS AND DESIGN A cross-sectional study was carried out by the psychiatry department of a tertiary care hospital in collaboration with the Radiation Medicine Centre. MATERIALS AND METHODS Eighteen male patients with schizophrenia in different phases of treatment underwent an 18F-deoxyglucose positron emission tomography scan in a resting state 12 hours after the last dose of antipsychotic. STATISTICAL ANALYSIS The types and duration of treatment were then compared with the regional glucose uptake in 14 predetermined regions of interest. The relative Uptake Values were further compared using SPSS 11.0. RESULTS An immediate increase followed by a decrease in cortical uptake was noted while the basal ganglia uptake remained high, albeit with a decreasing trend. Typical antipsychotics were associated with lower frontal cortical and higher basal ganglia and cerebellar uptake as compared to atypical antipsychotics. CONCLUSION The differential influence of the type and duration of antipsychotic on glucose uptake suggests a possible trend towards long-term side effects with typical medications that were not noted on clinical examination. This however needs to be confirmed with larger, controlled studies.

Relapse of cervical cancer presenting as symptoms of Collet-Sicard syndrome with metastatic subcutaneous and adrenal deposits.

A 35-year-old woman—who had been diagnosed with stage IB squamous-cell carcinoma of the cervix, treated with Wertheim’s hysterectomy followed by external-beam radiation to the pelvis (50 Gy in 25 fractions over 5 weeks), and disease-free for 13 months—presented to us with recent onset dysphagia, dysarthria, and deviation of the right side of the tongue. Clinical examination revealed palsy of the lower four cranial nerves, shown by loss of gag refl ex, weakness of the right shoulder, and deviation of the tongue and soft palate to the right side. Whole-body 18-fl uorodeoxyglucose-PET ([ 18 F]FDG-PET; the brain was included because of neurological symptoms) showed a curvilinear area of intense uptake of fl uorodeoxyglucose on the right posterior of the skull base (fi gure A). [ 18 F]FDG-PET also revealed abnormal disease foci that were symptomatically silent in: the right adrenal gland (confi rmed by repeat postfurosemide [ 18 F]FDG-PET that was limited to the abdomen), a subcutaneous nodule in the right arm, the mediastinum, and the right iliac bone (fi gure A). The subcutaneous nodule was hitherto unknown and serendipitously discovered by [ 18

Uptake of Tc-99m MDP by a primitive neuroectodermal tumor of the liver.

A 10-year-old girl had a large mass occupying the right half of the abdomen associated with the liver. Aspiration cytology suggested primitive neuroectodermal tumor. A bone scan revealed avid uptake in the liver mass, and subsequent colloid and hepatobiliary imaging showed a large intrahepatic avascular mass displacing the gallbladder and right kidney. A CT scan showed amorphous calcification in the mass that explained the uptake of Tc-99m MDP. A literature survey has not revealed reports of primitive neuroectodermal tumor of the liver demonstrated on bone scanning. The 1-131 MIBG scan showed no uptake.

Unilateral testicular relapse of abdominal non-Hodgkin lymphoma detected by FDG-PET

Moderately intense FDG uptake in the testis is regarded as a normal variant, especially in younger patients [1, 2]. In one study [1], physiological testicular uptake was found to be approximately 6.0 and 3.6 times higher than muscle and blood levels, respectively. This uptake of FDG into the normal testis declines with age [1]. However, intense uptake, especially if unilateral, can signify disease involvement. A 7-year-old boy presented with a 3-month history of fever, pain and an abdominal mass. Abdominal CT revealed multiple hypodense nodules in both kidneys and a large, irregular intraperitoneal mass infiltrating the mesentery, engulfing some small-bowel loops and causing compression and displacement of the urinary bladder. CTguided biopsy of the mass revealed it to be non-Hodgkin lymphoma (NHL). He was treated with eight cycles of chemotherapy over 6 months. One month after the last cycle, CT demonstrated a small residual soft-tissue mass in the pelvic cavity infiltrating adjacent bowel loops as well as the superolateral aspect of the urinary bladder. There was near-total regression of the lymphomatous deposits in both kidneys with a residual small nodule observed in the posterior cortex of the right kidney. Whole-body FDG-PET (Fig. 1) performed 1 month after the last cycle of chemotherapy demonstrated uptake in the mesenteric mass and the residual nodule in the right kidney,