Introduction: Hodgkin lymphoma (HL) is a highly curable lymphoma with cure rates of over 80% and even higher with limited stage disease. Computerized tomography (CT) scan is currently the recommended modality in staging and assessment of response to therapy in patients with HL. However, CT has its limitations. This study describes our experience with patients of HL where fluorodeoxyglucose positron emission tomography (FDG-PET)-CT scan helped decide further management, after completion of chemotherapy. Methodology: This is a retrospective review of the records of children diagnosed with HL at our center. Patients with post-treatment CT scan showing evidence of residual disease, who underwent FDG-PET-CT for deciding further management, were included in the study. Results: Thirty one patients were diagnosed with HL during this period. Nine patients were eligible and underwent PET-CT. In 8 out of 9 patients, PET-CT showed no scan evidence of active disease. In one patient, FDG-PET-CT carried out after completion of chemotherapy showed evidence of active disease and was given radiotherapy. Conclusion: FDG-PET-CT is a promising modality in deciding further management when there is discordance between the post-treatment CT scan and clinical condition of the patient with HL thus avoiding unnecessary chemotherapy/radiotherapy.

Objective: The aim of this study was to evaluate the use of delayed pelvic ¹⁸ F-2-fluoro-2-deoxy-D-glucose-positron emission tomography combined with the computed tomography (FDG-PET/CT) imaging, according to a standardized protocol including, pre-hydration and forced diuresis, for the detection of primary bladder cancer. Materials and Methods: We evaluated 38 consecutive patients with primary cT1-4 bladder cancer. They underwent standard FDG-PET/CT followed by delayed pelvic imaging after administration of 20 mg furosemide intravenously and extra oral water intake of 0.5 L. Two observers, blinded for patient data, scored both image sets for tumor visibility using a 3-point ordinal scale: (1) negative; (2) indeterminate; (3) positive. FDG-PET/CT findings were compared with histopathology and/or follow-up imaging. Results: The procedure was completed successfully in 37/38 patients and the reference standard revealed a bladder tumor in 26/37 patients. Delayed PET/CT images showed reduction of urinary bladder activity to (near) background levels in 17 of 37 cases (45.9%). Standard PET/CT detected hyper-metabolic bladder lesions in 15/37 patients (40.5%) of which 8 were indeterminate. Delayed FDG-PET/CT showed hyper-metabolic bladder lesions in 30/37 (81.1%) patients, of which 5 were indeterminate. When indeterminate lesions were considered positive, the sensitivity of standard and delayed PET/CT was 46% versus 88%, respectively. The specificity was 72% versus 36%. When indeterminate lesions were considered negative, the sensitivity of standard and delayed PET/CT was 23% and 85%. The specificity was 93% versus 73%. Conclusions: Our data suggest that delayed pelvic FDG-PET/CT imaging after forced detects more primary bladder tumors than standard FDG-PET/CT protocols. However, indeterminate bladder lesions on delayed PET/CT remain a problem and should be interpreted cautiously in order to avoid false positive results.

Aims: The aim of this study was to evaluate whether low-attenuation oral contrast agent (milk with 4% fat ) in PET-CT gastrointestinal studies(GIT) improves the diagnostic accuracy. Justification for the Study: Traditional high-contrast oral agents like iodine solutions, and barium suspensions which due to overcorrection problems in PET-CT interpretation lowers the accuracy of diagnosis. Traditional low-attenuation oral contrast agents are water, air, fat containing agents used with 12.5% corn oil and polyethylene glycol .Volumen is a 0.1% barium suspension and has found favor in visualization of mural features as well as for GIT distension. Milk with 4% fat content has also been tested out in radiological studies and found to be as effective as Volumen. As the former is more easily available, palatable, and acceptable especially, by children it needed to be tested in the visualization of the GIT in the PET-CT scenario. Materials and Methods: Total of 112 patients were divided into 3 groups. Group I: No intervention (18 subjects) Group II: Water (55 subjects): All these patients had 500-750 ml of water 5-10 min before PET examination. Group III: Milk (39 subjects) 500 ml of milk (4% fat content with no additives) was given 40-45 min after 18F-Fluorodeoxyglucose( FDG) injection and another 500 ml 5 min before scan was started. For patients intolerant to milk the same procedure was carried out with soya milk . Group IV comparison with data with Volumen Results: Criteria for evaluation of Gut distension on CT images: (0) No distension, (1) 1 cm distension, (2) 1-2 cm distension, (3) >2 cm distension. For the study analysis, % of patients with criteria 2 and 3 were considered as good visualization. Stomach distension was16%, 47%, 88%, 75% in Gr1-4 respectively, Duodenum-11%, 27% 88%, 86%, Jejunum - 33%, 49%, 89%, 76%* Ileum-40%, 77%, 82%, 80%* and Colon - 55%, 58%, 7 4%. Visualization of bowel wall with enhancement of stomach, duodenum, jejunum, and ileum and proximal colon was significantly better with milk than with water or no intervention. Intensity of FDG uptake was mild to moderate with no overcorrection in normal bowel loops and in patients with GIT lesions. Gaseous distension was not increased with milk as an oral contrast agent. Images of patients with bowel tumor was well-delineated with milk administration as the FDG uptake ratio of tumor to gut was high. Conclusion: Distension and visualization of the stomach, duodenum, jejunum, and proximal bowel was significantly improved with milk as a low-attenuation contrast agent. Intensity of FDG uptake was not significantly increased in normal gut and delineation of tumor with increased FDG uptake was improved as overcorrection was minimal.

Introduction: Abnormal morphologic findings in imaging were thought to explain the etiology of low back pain (LBP). However, it is now known that variety of morphologic abnormalities is noted even in asymptomatic individuals. Single photon emission computed tomography/computed tomography (SPECT/CT) could be used to differentiate incidental findings from clinically significant findings. Objective: This study was performed to define the SPECT/CT patterns in patients with LBP and to correlate these with clinical and magnetic resonance imaging (MRI) findings. Materials and Methods: Thirty adult patients with LBP of duration 3 months or more were prospectively evaluated in this study. Patients with known or suspected malignancy, trauma or infectious processes were excluded. A detailed history of sensory and motor symptoms and neurologic examination was performed. All the patients were subjected to MRI and bone scintigraphy with hybrid SPECT/CT of the lumbo-sacral spine within 1 month of each other. The patients were classified into those with and without neurologic symptoms, activity limitation. The findings of clinical examination and imaging were compared. MRI and SPECT/CT findings were also compared. Results: Thirty patients (18 men and 12 women; mean age 38 years; range 17-64 years) were eligible for the study. Clinically, 14 of 30 (46%) had neurologic signs and or symptoms. Six of the 30 patients (20%) had positive straight leg raising test (SLRT). Twenty-two of the 30 patients (73%) had SPECT abnormality. Most frequent SPECT/CT abnormality was tracer uptake in the anterior part of vertebral body with osteophytes/sclerotic changes. Significant positive agreement was noted between this finding and MRI evidence of degenerative disc disease. Only 13% of patients had more than one abnormality in SPECT. All 30 patients had MRI abnormalities. The most frequent abnormality was degenerative disc disease and facet joint arthropathy. MRI showed single intervertebral disc abnormality in 36% of the patients and more than one intervertebral disc abnormality in remaining 64% patients. Fifteen of the 30 patients had facet joint arthropathy. 60% of these patients had involvement of more than one level facet joints while 38% had associated inter vertebral disc disease. 83% of the patients with positive SLRT had SPECT and MRI abnormalities. 100% of patients with neurologic symptoms had SPECT and MRI abnormalities. Conclusion: Addition of hybrid SPECT/CT data will help differentiate incidental from significant MRI abnormalities as all patients with LBP have MRI abnormalities and most have MRI abnormalities at multiple sites. Tracer uptake in the anterior part of the vertebral body represents degenerative disc disease. MRI is sensitive and SPECT/CT is specific for facet joint arthropathy. Both investigations are best used complementary to each other.

Purpose: Valuate complementary role of ^99m Tc-MDP bone scan and ^99m Technetium hexamethylpropylene-amineoxime ( ^99m Tc-HMPAO) labeled leukocyte scintigraphy in diagnosis of bone infection. Patients and Methods: Ninety one sites suspected to have bone infection were divided in to two groups: Group I 49 sites with current endo-prothesis; and group II 42 sites with no prosthesis. All patients were subjected to serial images of ^99m Tc-HMPAO labeled leukocyte ( ^99m Tc-white blood cells (WBCs)), triple phase bone scan ( ^99m Tc-MDP) and plain X-ray, in addition to clinical and bacteriological assessment, together with follow-up. Results: The overall sensitivity (Sn) was found to be 34.9%, 95.4%, and 86% for plain X-ray, ^99m Tc-MDP, and ^99m Tc-WBCs respectively. Concerning specificity (Sp) was found to be 47.9%, 45.8%, and 91.7% respectively for the three imaging modalities. ^99m Tc-WBCs showed better Sn, Sp, and accuracy in group I (95%, 93.1% and 93.9%, respectively) compared to 40%, 41.4%, and 40.8% for plain X-ray and 90%, 62%, and 73.5% respectively for ^99m Tc-MDP. On the other hand, ^99m Tc-MDP proved to have best Sn 100% versus 78.3% and 30.4% for ^99m Tc-WBCs and plain X-ray respectively. Yet, Sp and accuracy was found to best for ^99m Tc-WBCs (89.5% and 83.3% respectively) compared to 57.9% and 42.9% for plain X-ray and 21.1% and 64.3% for ^99m Tc-MDP. Conclusion: Combined imaging with ^99m Tc-WBCs and ^99m Tc-MDP proved to be effective in early detection of bone infection in the presence or absence of prosthesis.

Objective: The aim of this is to evaluate the negative predictive value (NPV) of a normal gated myocardial perfusion imaging (NGMPI) with exercise and dipyridamole in a propensity matched population. Materials and Methods: This is a prospective study conducted at Nuclear Cardiology Department of Karachi Institute of Heart Diseases, Karachi from December 2008 until June 2010. A total of 809 patients with a NGMPI with adequate exercise (558/809) or dipyridamole (251/809) stress were included and followed-up for 12-30 months (mean 24 ± 3 months) for fatal or non-fatal myocardial infarctions (MI). Results: Mean ejection fraction (%), end diastolic volume (ml), and end systolic volume (ml) in exercise and dipyridamole cohorts were (72 ± 08, 66 ± 11), (68 ± 13, 81 ± 17), and (19 ± 11, 26 ± 12) respectively. On follow-up, in dipyridamole cohort 2 fatal and 6 non-fatal MIs were reported. While in exercise cohort only 2 non-fatal MIs were reported. The NPV of a NGMPI with exercise was 99.7% (95% confidence interval [CI] 98.93-99.96%) with an event rate of 0.3% (95% CI; 0.03-0.6%) and annualized event rate of 0.15%. The NPV of NGMPI with dipyridamole was 96.80% (95% CI; 2.2-4.3%) with an event rate of 3.2% (95% CI; 1.39-3.83%) and annualized event rate of approximately 1.6%. Event free survival for dipyridamole group was significantly lower than exercise analyzed by Log-rank test (14.509, P < 0.001). Conclusion: A NGMPI with dipyridamole stress has higher event rate (low-NPV) as compared with exercise and this raises concern over its credibility to label these patients into low-risk group.

Introduction: Deconvolution and the Rutland-Patlak (R-P) plot are two of the most commonly used methods for analyzing dynamic radionuclide renography. Both methods allow estimation of absolute and relative renal uptake of radiopharmaceutical and of its rate of transit through the kidney. Materials and Methods: Seventeen patients (32 kidneys) were referred for further evaluation by renal scanning. All patients were positioned supine with their backs to the scintillation gamma camera, so that the kidneys and the heart are both in the field of view. Approximately 5-7 mCi of ^99m Tc-DTPA (diethylinetriamine penta-acetic acid) in about 0.5 ml of saline is injected intravenously and sequential 20 s frames were acquired, the study on each patient lasts for approximately 20 min. The time-activity curves of the parenchymal region of interest of each kidney, as well as the heart were obtained for analysis. The data were then analyzed with deconvolution and the R-P plot. Results: A strong positive association (n0 = 32; r = 0.83; R2 = 0.68) was found between the values that obtained by applying the two methods. Bland-Altman statistical analysis demonstrated that ninety seven percent of the values in the study (31 cases from 32 cases, 97% of the cases) were within limits of agreement (mean ± 1.96 standard deviation). Conclusion: We believe that R-P analysis method is expected to be more reproducible than iterative deconvolution method, because the deconvolution technique (the iterative method) relies heavily on the accuracy of the first point analyzed, as any errors are carried forward into the calculations of all the subsequent points, whereas R-P technique is based on an initial analysis of the data by means of the R-P plot, and it can be considered as an alternative technique to find and calculate the renal uptake rate.

Adrenal gland is a common site of metastasis in many cancers but it is very rare in oesophageal carcinoma. We report one such case found to have adrenal metastasis on follow-up PET/computed tomography scan.

Lipodystrophy (LD) is a serious complication of highly active anti-retroviral therapy, characterized by peripheral fat wasting, central adiposity and metabolic changes. Since the disfiguration caused by LD is permanent, the focus of management is on early detection to arrest progression. We report a case where ancillary finding of increased fluorine-18 fluoro-2-deoxyglucose (F-18 FDG) uptake in the sub-cutaneous fat helped early detection of LD and led to early intervention to arrest progression. Though F-18 FDG positron emission tomography/computed tomography scan is not recommended to diagnose LD, conscious reporting of this finding when present can greatly influence patient management.

A 67-year-old male presented to our institute with history of paraparesis with decreased sensation and loss of bladder and bowel control. The diagnostic work up revealed an extradural mass at spinal level D7-D12. He had laminectomy and the tumor was sub totally resected. Histological examination revealed non-hodgkin's lymphoma (NHL). The patient was worked up for disease anywhere else in the body and was confirmed to have primary extradural non-hodgkin's lymphoma.

Increased uptake of F-18 fluorodeoxyglucose (FDG) has been reported in thyroiditis and hypothyroidism. The authors present a case where increased FDG uptake in the thyroid was subsequently corroborated with a pertechnetate scan and thyroid hormone levels to diagnose previously undetected Graves' disease in a patient of non-Hodgkin's lymphoma being followed-up with positron emission tomography for disease recurrence.

Penile cancer is an uncommon malignancy which of the management depends on the clinical stage and location of the lesion. Positron emission tomography/computerized tomography (PET/CT) is a promising method for detection of distant metastatic lesions and therapeutic strategy planning. Here, we report a case of penile squamous cell carcinoma of 57-year-old male patient, was referred to PET/CT department for investigation of metastases. There were significantly increased fluoro-18 fluorodeoxyglucose activities in supradiaphragmatic and infradiaphragmatic lymphatic stations.

A young male patient with end stage renal disease underwent renal allograft having dual arterial supply. Immediate post-operative urine output dropped, an urgent Technetium-99m-mercaptoacetyltriglycine ( ^99m Tc-MAG3) renogram revealed non-visualized upper-half and the preserved perfusion and parenchymal function of the small transplant kidney. Patient was re-explored and re-anastomosis was performed.A renogram at 24h post re-anastomosis revealed increase in the size of renal allograft, with preserved perfusion to the upper-half of transplant. Transplant kidney biopsy of the Upper-half showed acute tubular necrosis. 99mTc-MAG3renogram at 10 days post re-vascularization remains unchanged with persistent improvement at 2 months follow-up. We conclude that early recognition of renal functional loss allows early management and the high probability of salvaging the renal function.

Meckel's scan is a common procedure performed in nuclear medicine. Single-photon emission computed tomography/computed tomography (SPECT/CT) in a suspected case of heterotopic location of gastric mucosa can increase the accuracy of its anatomic localization. We present two suspected cases of Meckel's diverticulum in, which SPECT/CT co-registration has helped in better localization of the pathology.

Chordoma is a malignant tumor arising from the remnants of the notochord, and is the most frequent primitive tumor of the sacrum. While most sacral tumors show increased concentration of bone-seeking radiopharmaceuticals, chordomas usually exhibit decreased uptake. The authors present an image of a sacrococcygeal chordoma with osteolysis and increased uptake of 99mTc methylene diphosphonate on planar and single photon emission computed tomography/computed tomography bone scintigraphy.

The primary hypertrophic osteoarthropathy (HOA) (pachydermoperiostosis) is a rare hereditary disease characterized by skin manifestations (pachydermia), digital clubbing and proliferation of periosteum (periostitis) with sub-periosteal new bone formation. We describe here a case who presented with seborrheic dermatitis and joint pain of both hands on work up matched satisfactorily with the complete form of primary HOA. The identification of secondary form being relatively common among clinicians and hence the importance of recognizing the primary form, which is a difficult to treat condition is discussed here.

A 55-year-old female presented with complaints of pain in the left hip radiating to the left lower limb since 1 year. Computed tomography (CT) abdomen and pelvis revealed bony destruction of pubic symphysis with associated soft tissue component suspicious of infective or metastatic etiology. Magnetic resonance imaging Lumbo-sacral spine performed later revealed altered bone marrow signal in sacral 1-3 vertebrae. Wholebody bone scan with 25 mCi of Tc-99m methylene diphosphonate (MDP) was performed, which revealed multiple skeletal metastases and extraosseous soft tissue uptake was seen involving multiple muscles. We performed single photon emission tomography single photon emission computed tomography (SPECT)/computed tomography (CT) images to precisely delineate the muscle involved and noted calcification on CT images in one of the muscle at site of Tc-99m MDP uptake, no definite calcification was noted in the other muscles. Thus, the final diagnosis was multiple skeletal metastasis with metastatic calcification in multiple muscle from an unknown primary.

We describe the case of chylothorax after esophagectomy for esophageal carcinoma. Lymphoscintigraphy with Tc-99m-human serum albumin-diethylenetriaminepentaacetic acid showed an abnormal radioisotope accumulation on the left side of the thoracic duct. Single-photon emission computed tomography (SPECT) combined with computed tomography (CT) revealed a hot spot directly on the site at, which the thoracic duct was ligated during surgery, which was the suggested site of chyle leakage. We emphasize that lymphoscintigraphy with SPECT/CT is very useful tool for accurately identifying the site of the chyle leakage.