Impact of Fluoro-Choline PET/CT in Reduction in Failed Parathyroid Localization in Primary Hyperparathyroidism.

INTRODUCTION: Accurate localization of the pathological parathyroid gland is a prerequisite for minimally invasive surgical management of hyperparathyroidism (HPT). Poor imaging or discordance in odd situations like ectopic adenomas, parathyroid hyperplasia, syndromic HPT results in localization dilemma thus causing failed parathyroidectomy. We studied the impact of Fluoro-Choline (FCH) PET/CT imaging in reduction in localization failure of parathyroid adenoma. MATERIALS AND METHODS: We did a retrospective observational study (2018-2021) of HPT among which 97 patients underwent focused parathyroidectomy (FP). All patients had undergone ultrasound imaging and 99mTc-sestaMIBI scan with early SPECT/CT (MIBI). When this preliminary imaging was doubtful or negative or multiple lesions were expected, FCH PET/CT was performed. We compared the localization accuracy of MIBI scan and FCH PET/CT with surgical outcomes as reference standard. RESULTS: MIBI scan showed overall lesion detection rate (LDR) of 88.65% in localization of pathological parathyroid gland in 97 patients. The addition of FCH PET/CT improved the overall lesion detection to 97.9%. The overall possible localization failure was reduced from 11.34 to 2.06% with the addition of FCH PET/CT (p < 0.05). Out of 97 patients of FP, 87 patients showed features of parathyroid adenoma. Single hyperplastic gland was seen in 7 patients, lipoadenoma was seen in 1 patient and 1 patient had features suggestive of parathyroiditis on histopathology. FCH PET/CT was a useful adjunct and showed significant reduction in localization failure of parathyroid adenoma.

Impact of intraoperative MRI on outcomes in epilepsy surgery: preliminary experience of two years.

PURPOSE: To determine the impact of intraoperative magnetic resonance imaging (iMRI) in epilepsy surgeries on the extent of surgical resection and seizure outcome along with its feasibility and limitations. METHODS: Patients with pharmacoresistant epilepsy (PRE), who underwent surgeries in operating theater equipped with high-field 1.5-Tesla MRI, were evaluated for extent of resection, operative time, scanning time, pathologies, resultant extra resection, and seizure outcomes. RESULTS: Thirty-nine patients with mean age of 18 (range: 3-65) years with PRE underwent surgical intervention. Mean duration of epilepsy was 10.2 years. Surgical interventions included tumor resection (31%), resection of focal cortical dysplasia (28%), mesial temporal lobe surgeries (18%), and disconnection surgeries (23%). iMRI alone, apart from navigation and electrophysiology, improved resection rates in 13% (5 out of 39) of these patients. In lesional group, iMRI modified operative strategy resulting in increased resections in 21% (5/23) patients. Complete resection was observed in 87% of patients. iMRI scanning time constituted 25% (mean: 72 ± 21 min) of time spent under anesthesia by the patient. Major and minor complications were observed in 2.5% and 7.5% of patients, respectively. The mean follow-up was 14 months. Favorable postoperative seizure control (Engel Classes I and II) was achieved in 85% and complete seizure freedom was achieved in 77% of patients (Engel Class IA) at 1-year follow-up. CONCLUSIONS: iMRI increases the extent of resection mainly in lesional epilepsy surgeries translating into good seizure outcomes but not found to be much beneficial in prototype mesial temporal sclerosis surgeries and disconnection surgeries.

Multi-time point imaging in 99m Tc-pertechnetate scintigraphy of ectopic gastric mucosa in duplication cysts: value-added services.

OBJECTIVES: The aim of our study was to describe the scintigraphic patterns of 99m Tc-pertechnetate uptake in patients who were referred to the department of nuclear medicine for evaluating and diagnosing ectopic gastric mucosa in foregut and midgut duplication cysts. MATERIALS AND METHODS: This hospital-based, retrospective cum prospective research spans a period of 8 years from April 2014 to January 2022. Previous hospital medical records were analyzed and subsequently, a database was prepared which included the age, sex, clinical indication of a 99m Tc-pertechnetate scan, and the planar and SPECT-computed tomography (CT) imaging findings. Postoperative histopathological reports were available for 21 patients. Dynamic and planar static imaging was performed. We included SPECT-CT in suspected duplication cysts to increase the sensitivity and specificity which is a tradeoff for a small amount of additional radiation exposure. A total of 69 patients were subjected to a 99m Tc-pertechnetate scan for suspected foregut or midgut duplication cysts. All were subjected to dynamic planar and delayed static images up to 24 h or until focal uptake of radiotracer was noted which corroborated the anatomical findings, whichever was earlier. SPECT-CT was performed along with the planar study in 31 patients which confirmed the findings. Previously performed CT scans were used for anatomical correlation in the remaining ones. RESULTS: Duplication cysts were localized in a total of 28 patients (19 foregut duplication cysts and 12 small bowel duplications - 3 patients had dual duplication cysts, both foregut, and midgut). Forty-one patients had no scintigraphic evidence of ectopic gastric mucosa. Of these 69 patients, histopathological diagnosis was available for 21 patients (22 lesions). The report was concordant with the scan findings in 15 patients (16 lesions) and 6 patients showed discordance in histopathological diagnosis and scan findings. CONCLUSION: In conclusion, multi-time point imaging is the key to diagnosing ectopic gastric mucosa of various sizes and in various locations. An abnormal radiotracer uptake in dynamic sequences, even before the appearance of the stomach in the region of the small bowel is indicative of intestinal duplication, and delayed radiotracer visualization in the region of the thorax is characteristic of intrathoracic foregut duplication cyst.

Gallium-68-DOTA-NOC PET/CT of patients with gastroenteropancreatic neuroendocrine tumors: a prospective single-center study.

OBJECTIVE: The objective of this study was to evaluate the role of (68)Ga-labeled [1, 4, 7, 10-tetraazacyclododecane-1, 4, 7, 10-tetraacetic acid]-1-NaI(3)-octreotide (DOTA-NOC) PET/CT in the diagnosis and management of gastroenteropancreatic neuroendocrine tumors (NETs). SUBJECTS AND METHODS: One hundred nine patients (median age, 50 years) with gastroenteropancreatic NETs underwent (68)Ga-DOTA-NOC PET/CT. PET/CT was performed after injection of 132-222 MBq (4-6 mCi) of (68)Ga-DOTA-NOC. Images were evaluated by two experienced nuclear medicine physicians both qualitatively as well as quantitatively (maximum standardized uptake value [SUV(max)]). Results of PET/CT were compared with the results of conventional imaging. Histopathology results, when available, and follow-up PET/CT or conventional imaging with biochemical markers were considered to be the reference standards. RESULTS: Gallium-68-DOTA-NOC PET/CT showed sensitivity and specificity of 78.3% and 92.5%, respectively, for primary tumor and 97.4% and 100% for metastases. It was better than a conventional imaging modality for the detection of both primary tumor (p < 0.001) and metastases (p < 0.0001). It changed the management strategy in 21 patients (19%) and supported management decisions in 32 patients (29%). CONCLUSION: Gallium-68-DOTA-NOC PET/CT appears to be a highly sensitive and specific modality for the detection of gastroenteropancreatic NET. It is better than conventional imaging for the evaluation of gastroenteropancreatic NETs and can have a significant impact on patient management.

F-18 FDG PET-CT for predicting survival in patients with recurrent glioma: a prospective study.

INTRODUCTION: Recurrent gliomas are usually histologically high grade; either due to recurrence of a de novo high-grade primary or anaplastic transformation in case of low-grade tumors. Survival in these patients is variable. The objective of the present study is to evaluate the role of FDG PET-CT for predicting survival in a large group of patients with suspected recurrent glioma. METHODS: A total of 81 previously treated histopathologically proven glioma patients; with clinical and conventional imaging findings suspicious of recurrence were included in this study. All patients underwent FDG PET-CT study. Based on tumor to white matter (T/W) and tumor to grey matter (T/G) ratios, all lesions were scored on PET-CT (PET scores 0, 1 and 2). Patients were followed up clinically and by repeated imaging. Data was censored, if the patient died of disease or at the end of the study. Survival analysis was done for each variable employing univariate analysis followed by multivariate analysis, using variables found significant on univariate analysis. RESULTS: PET score was found to be the most significant predictor of survival in univariate and multivariate analysis (p 0.003). Patients having PET score 2 had poorer survival compared to both PET score 0 (p 0.001) and PET score 1 (p 0.004). Other covariates found to have significant correlation with survival were primary treatment modality and clinical symptoms at the time of recurrence. CONCLUSION: FDG uptake on PET-CT is a strong predictor of survival in patients with suspected recurrent glioma.

Designing and Comparing Performances of Image Processing Pipeline for Enhancement of I-131-metaiodobenzylguanidine Images.

OBJECTIVE: An image processing pipeline can have more than one image processing technique in sequence, and the output of the first technique becomes input for the next technique and so on. In this study, we have designed and compared the performances of image processing pipelines for enhancement of I-131-metaiodobenzylguanidine (mIBG) images. MATERIALS AND METHODS: Five different image processing pipelines (A [Gaussian filter, normalization], B [histogram specification (image 1), Gaussian filter, normalization], C [histogram specification (image 2), Gaussian filter, normalization], D [{histogram specification (image 3), Gaussian filter, and normalization], and E [histogram specification (image 4), Gaussian filter, normalization]) were designed and their performances were evaluated on I-131-mIBG images (n = 122). The image quality was assessed objectively using Perception-based Image Quality Evaluator (PIQE) score and subjectively (on scale 1-4) by two nuclear medicine physician. Sign test was applied to find the statistically significant difference between the image quality obtained using image processing pipelines. We applied test of proportion to compute difference in proportion of image quality score assigned to images obtained using image processing pipelines. RESULTS: Based on PIQE score, the quality of images obtained using all the five image processing pipelines were significantly better than that of input images (P < 0.001). The highest image quality score (=4) was assigned maximum number of times (n = 90) to the images obtained using image processing pipeline D and was significantly different from that of the second best image processing pipeline E (P = 0.015). CONCLUSIONS: The image processing pipeline D was found to be better for enhancement of I-131-mIBG images.

Fuzzy logic-based moving average filters for reducing noise from Tc-99m-sestamibi parathyroid images.

INTRODUCTION: The objective of the study was to use fuzzy logic-based moving average filters for reducing noise from Tc-99m-sestamibi parathyroid images and to compare its performance with classical moving average filters. METHODS: Sixty-eight Tc-99m-sestamibi parathyroid images (33 image zoom 1.0, 35 images zoom 2.0) were filtered using symmetric triangular fuzzy filters with the moving average (TMAV), asymmetric triangular fuzzy filters with the moving average (ATMAV) and classical moving average filter (MAV) with moving average within a square window of dimension N × N pixels (N=3,5,7,9,11). The relative filtering performance was compared both objectively (using Brisque score) and subjectively [by two nuclear medicine physicians on a 4-point scale (1 = nondiagnostic; 2 = diagnostic; 3 = good; and 4 = excellent image quality)]. The nonparametric two-sample Kolmogorov-Smirnov test was applied to find the statistically significant difference between the quality of input and their corresponding filtered images. RESULTS: The Brisque score assigned to MAV filtered zoom 2.0 images (MAV_3, median = -0.61) were significantly smaller than that of their input images (median = 53.84, at P = 1) and fuzzy filtered images (TMAV_3, median = 0.44, at P = 0.89 and ATMAV_3, median =8.26, at P = 0.97). The sum of average subjective image quality score for input, MAV_3, TMAV_3, TMAV_5, ATMAV_3, and ATMAV_5 were 148, 221, 221.5, 198,171,253 and 237.5, respectively. CONCLUSION: On the basis of subjective assessment, the performance of ATMAV_3 fuzzy filter was found to be better compared to the classical moving average filter in reducing noise from Tc-99m-sestambi parathyroid images.

Tc-99m ethylcysteinate dimer SPECT in the differential diagnosis of dementias.

BACKGROUND: Dementias produce deficits in perfusion, in part, reflecting decreased metabolic needs. Single photon emission computed tomography (SPECT) studies have reported characteristic anterior-to-posterior perfusion gradients that permit distinction between the various forms of dementia. AIM: We undertook this study to evaluate the role of visual analysis of SPECT perfusion patterns for the differential diagnosis of types of degenerative dementia. MATERIALS AND METHODS: Tc-99m ethylcysteinate dimer (ECD) was used with a dual-head scanner to generate perfusion images of the brain in 136 patients referred from the dementia clinic. Diagnosis was made by the nuclear physician unaware of clinical diagnosis. RESULTS: Sensitivity, specificity, positive predictive value and negative predictive value of perfusion studies for Alzheimer's dementia were 93.42%, 95.12%, 97.26%, and 88.63%, respectively, and for frontotemporal dementia were 96.29%, 98%, 96.29%, and 98.88%, respectively. CONCLUSIONS: Tc-99m ECD brain perfusion SPECT is useful in the differential diagnosis of dementia with particular reference to AD as well as FTD.

Evaluation of CYFRA 21.1 as a Dedifferentiation Marker of Advanced Thyroid Cancer.

PURPOSE OF THE STUDY: Well-differentiated thyroid carcinomas have good prognosis, but as it de-differentiates, the survival rates go down. Early identification of such patients needs a marker which indicates the dedifferentiation process. CYFRA 21.1 has also shown to be increased in patients with 131I refractory thyroid cancer. We tested whether CYFRA 21.1 can differentiate between 131I avid and refractory tumors. METHODOLOGY: Well-differentiated thyroid cancer patients with known distant metastases were accrued and tested for stimulated and unstimulated thyroglobulin and CYFRA 21.1. All patients underwent 131I whole-body scan, 131I post therapy scan, and 18F-Fluorodeoxyglucose positron emission tomography-computed tomography. Those with even a single 131I nonavid lesion were considered 131I refractory disease. CYFRA 21.1 of both 131I avid and nonavid was compared, and CYFRA 21.1 levels against disease extent were analyzed. RESULTS: CYFRA 21.1 levels were significantly elevated in 131I refractory group. A cutoff value of 2.07 ng/ml distinguished between 131I avid and refractory disease with high sensitivity and specificity (88% and 89. 7%, respectively). However, CYFRA 21.1 levels were similar in patients when analyzed based on disease sites. CONCLUSION: CYFRA 21.1 can be utilized to differentiate between 131I avid and refractory diseases. Further long-term studies are required to use it as a predictive and prognostic marker.

Restoration of I-131 whole body image using a Wiener filter.

INTRODUCTION: The aim of the study was to restore I-131 whole body image using Wiener filter. MATERIAL AND METHODS: A set of 50 I-131 whole body images acquired using Symbia E dual head gamma camera with high energy general purpose collimator was used. The Gaussian point-spread function (PSF) characterised by the size (3, 5, 7, 9, 11, and 13 pixels) and corresponding standard deviation (0.5, 0.75, 1, 1.5, 1.75, and 2 pixels) and noise-to-signal power ratios (NSR: 0, 0.001, 0.01, 0.1, 0.2, 0.3, 0.4, and 0.5) were used as parameters for Wiener filter. Using the combinations of PSF and NSR, a total of 2450 images (50 × 49 = 2450 images, where 49 images include 1 input and 48 restored images for each input image) were generated and inspected by two nuclear medicine physicians. They selected one best image (the image which had less noise and better contrast between the lesion and background in comparison with the input image). Their results were analyzed. RESULTS: Compared to input image, the metastatic uptake in restored images was very easily perceived. The restored image obtained with PSF (size = 13, sigma = 2) and NSR = 0.3 had better signal-to-noise ratio in comparison to restored image obtained with PSF (size = 11, sigma = 1.75) and NSR = 0.2. CONCLUSION: The restored images with PSF (size = 13, sigma = 2) and NSR = 0.3 were found to have superior image quality in comparison with its input image.

Efficacy and Safety of 177Lu-PSMA-617 Radioligand Therapy in Metastatic Castration-Resistant Prostate Cancer Patients.

PURPOSE: The aim of this study was to evaluate the efficacy and safety of Lu-PSMA-617 radioligand therapy in metastatic castration-resistant prostate cancer (mCRPC). METHODS: In this prospective, single-arm, single-institutional study, 90 mCRPC patients with progressive disease (PD) on second-line hormonal therapy and/or docetaxel chemotherapy were recruited for the study. All patients underwent diagnostic Ga-PSMA-HBED-CC PET/CT, prior to inclusion for therapy. Included patients underwent Lu-PSMA-617 therapy at 8- to 12-weekly intervals. The primary end point was to assess the overall survival. The secondary and cosecondary end points included biochemical response assessment as per the Prostate Cancer Working Group 3 criteria, progression-free survival, radiological and molecular response criteria, clinical response, safety profile, and disease control rates. All the outcome parameters were evaluated in 90 patients except for the radiographic and molecular response, which was evaluated in 69 patients. RESULTS: The median age of patients was 66.5 years (range, 30-88 years). The median activity administered per cycle was 3.7 to 8 GBq ranging from 1 to 7 cycles, and patients were followed up over a median duration of 28 months. At 2- to 3-month interval after the first therapy and the end of the assessment, greater than 50% decline in prostate-specific antigen was observed in 32.2% and 45.5%, respectively. Univariate analysis did not reveal any variables such as prior therapies, laboratory parameters, concomitant hormonal therapy, and SUV patient parameters associated with prostate-specific antigen decline. Radiographic response by diagnostic CT revealed partial remission in 23% (16/69), stable disease in 54% (37/69), and PD in 23% (16/69) of patients. Molecular tumor response by PET Response Criteria in Solid Tumor 1 criteria revealed 19 (27.5%) of 69 patients with partial remission, 30 (43.5%) of 69 with stable disease, and 20 (29%) of 69 with PD. The disease control rates according to the radiographic and molecular response were 77% and 71%, respectively. The median overall survival and median progression-free survivals were 14 and 11.8 months, respectively. Toxicities related to radioligand therapy were low and transient with no serious adverse effects. CONCLUSIONS: Lu-PSMA-617 radionuclide therapy is a safe and effective approach to the treatment of mCRPC patients.

Usefulness of 99mTc-pertechnetate single-photon emission computed tomography in remnant mass estimation of postsurgical patients of differentiated thyroid cancer during internal dosimetry.

OBJECTIVE: No satisfactory methods exist for postsurgical remnant mass estimation required for dosimetric calculations in differentiated thyroid cancer patients undergoing I-131 remnant ablation. We estimated the remnant mass by Tc-99m pertechnetate single-photon emission computed tomography to calculate the radiation dose delivered. MATERIALS AND METHODS: Thyroid phantoms of known volumes (1.1-6 cm3) were fabricated, filled with different concentrations of Tc-99m pertechnetate activity, and single-photon emission computed tomography acquired on a dual head camera and processed with Hanning filter. Area of the organ on coronal slices was calculated at different thresholds and the sum was multiplied by slice thickness to get the volume. A threshold of 50% was found to distinguish the organ from the background activity and give the most accurate results. Remnant mass was calculated by this method in 50 patients of differentiated thyroid cancer after thyroid surgery. Effective half-life (EHL) of I-131 and 24 h radioactive iodine uptake (RAIU) were calculated by repeated neck count measurements for 4 days. After administering I-131 for therapy, 39 patients were followed up at 6 months and the effects of various parameters in achieving complete ablation were analyzed. RESULTS: Mean values of remnant mass, RAIU, and EHL were 6.6+/-4.3 g, 8.8+/-6.1%, and 4.5+/-0.9 days, respectively. Type of surgery, remnant mass, and RAIU were the most important predictors of complete ablation (P<0.05). Radiation-absorbed dose, EHL, and the administered activity had no significant effect on complete ablation. CONCLUSION: Remnant thyroid mass estimation by Tc-99m pertechnetate single-photon emission computed tomography is a simple technique and allows overcoming the dependence on structural imaging techniques or making empirical assumptions during dosimetry.

Development of a Simple Image Processing Application that Makes Abdominopelvic Tumor Visible on Positron Emission Tomography/Computed Tomography Image.

INTRODUCTION: In this study, we have developed a simple image processing application in MATLAB that uses suprathreshold stochastic resonance (SSR) and helps the user to visualize abdominopelvic tumor on the exported prediuretic positron emission tomography/computed tomography (PET/CT) images. METHODS: A brainstorming session was conducted for requirement analysis for the program. It was decided that program should load the screen captured PET/CT images and then produces output images in a window with a slider control that should enable the user to view the best image that visualizes the tumor, if present. The program was implemented on personal computer using Microsoft Windows and MATLAB R2013b. RESULTS: The program has option for the user to select the input image. For the selected image, it displays output images generated using SSR in a separate window having a slider control. The slider control enables the user to view images and select one which seems to provide the best visualization of the area(s) of interest. CONCLUSION: The developed application enables the user to select, process, and view output images in the process of utilizing SSR to detect the presence of abdominopelvic tumor on prediuretic PET/CT image.

Development and Validation of the Suprathreshold Stochastic Resonance-Based Image Processing Method for the Detection of Abdomino-pelvic Tumor on PET/CT Scans.

PURPOSE: The detection of abdomino-pelvic tumors embedded in or nearby radioactive urine containing 18F-FDG activity is a challenging task on PET/CT scan. In this study, we propose and validate the suprathreshold stochastic resonance-based image processing method for the detection of these tumors. METHODS: The method consists of the addition of noise to the input image, and then thresholding it that creates one frame of intermediate image. One hundred such frames were generated and averaged to get the final image. The method was implemented using MATLAB R2013b on a personal computer. Noisy image was generated using random Poisson variates corresponding to each pixel of the input image. In order to verify the method, 30 sets of pre-diuretic and its corresponding post-diuretic PET/CT scan images (25 tumor images and 5 control images with no tumor) were included. For each sets of pre-diuretic image (input image), 26 images (at threshold values equal to mean counts multiplied by a constant factor ranging from 1.0 to 2.6 with increment step of 0.1) were created and visually inspected, and the image that most closely matched with the gold standard (corresponding post-diuretic image) was selected as the final output image. These images were further evaluated by two nuclear medicine physicians. RESULTS: In 22 out of 25 images, tumor was successfully detected. In five control images, no false positives were reported. Thus, the empirical probability of detection of abdomino-pelvic tumors evaluates to 0.88. CONCLUSION: The proposed method was able to detect abdomino-pelvic tumors on pre-diuretic PET/CT scan with a high probability of success and no false positives.

Can ictal-MEG obviate the need for phase II monitoring in people with drug-refractory epilepsy? A prospective observational study.

PURPOSE: To determine if ictal-magnetoencephalography (ictal-MEG) source localization (SL) added information towards delineating the ictal-onset zone (IOZ), whether and how it helped final decision-making in epilepsy-surgery. METHODS: Definite focal clusters on ictal-MEG were available for 32 DRE-patients, data was analyzed (single equivalent current dipole (ECD) model), SL done. Clinical history, long-term video-EEG (VEEG) monitoring, epilepsy-protocol MRI, FDG-PET, ictal-SPECT and interictal-MEG were discussed at the multispeciality Epilepsy Surgery Case-conference (ESC). Cases were reviewed with ictal-MEG SL presented only at the last ESC (after decision using other available modalities). Patients were grouped as VEEG localization and MRI-lesion concordant (Group-A), discordant (Group-B), and no MRI-lesion (Group-C). Final hypothesis or decision, surgical outcome in those operated, and how ictal-MEG data influenced them were recorded. RESULTS: Five lesion-negative patients had identification of lesions after review of MRI with ictal-MEG SL. The difference between numbers of patients cleared for surgery without and with ictal MEG data was statistically significant (p=0.0044); but the difference in those cleared for phase II monitoring was not (p=1.00). Ictal MEG influenced decisions on possibility of surgery in 9 and converted decisions of phase II monitoring in 11 patients to electrocorticography-guided lesionectomy (20 in all; Group A-11, Group B-4, Group C-5); five were operated, with good seizure-control on follow-up. CONCLUSIONS: Delineation of IOZ by ictal-MEG helped convert DRE patients unsuitable for surgery or planned for phase II monitoring into candidates suitable for surgery, even ECoG-guided resections, and resulted in favorable outcomes in those who were operated.

Investigating the Role of Global Histogram Equalization Technique for 99mTechnetium-Methylene diphosphonate Bone Scan Image Enhancement.

PURPOSE OF THE STUDY: 99mTechnetium-methylene diphosphonate (99mTc-MDP) bone scan images have limited number of counts per pixel, and hence, they have inferior image quality compared to X-rays. Theoretically, global histogram equalization (GHE) technique can improve the contrast of a given image though practical benefits of doing so have only limited acceptance. In this study, we have investigated the effect of GHE technique for 99mTc-MDP-bone scan images. MATERIALS AND METHODS: A set of 89 low contrast 99mTc-MDP whole-body bone scan images were included in this study. These images were acquired with parallel hole collimation on Symbia E gamma camera. The images were then processed with histogram equalization technique. The image quality of input and processed images were reviewed by two nuclear medicine physicians on a 5-point scale where score of 1 is for very poor and 5 is for the best image quality. A statistical test was applied to find the significance of difference between the mean scores assigned to input and processed images. RESULTS: This technique improves the contrast of the images; however, oversaturation was noticed in the processed images. Student's t-test was applied, and a statistically significant difference in the input and processed image quality was found at P < 0.001 (with α = 0.05). However, further improvement in image quality is needed as per requirements of nuclear medicine physicians. CONCLUSION: GHE techniques can be used on low contrast bone scan images. In some of the cases, a histogram equalization technique in combination with some other postprocessing technique is useful.

Identification of optimal mask size parameter for noise filtering in 99mTc-methylene diphosphonate bone scintigraphy images.

Tc-methylene diphosphonate (Tc-MDP) bone scintigraphy images have limited number of counts per pixel. A noise filtering method based on local statistics of the image produces better results than a linear filter. However, the mask size has a significant effect on image quality. In this study, we have identified the optimal mask size that yields a good smooth bone scan image. Forty four bone scan images were processed using mask sizes 3, 5, 7, 9, 11, 13, and 15 pixels. The input and processed images were reviewed in two steps. In the first step, the images were inspected and the mask sizes that produced images with significant loss of clinical details in comparison with the input image were excluded. In the second step, the image quality of the 40 sets of images (each set had input image, and its corresponding three processed images with 3, 5, and 7-pixel masks) was assessed by two nuclear medicine physicians. They selected one good smooth image from each set of images. The image quality was also assessed quantitatively with a line profile. Fisher's exact test was used to find statistically significant differences in image quality processed with 5 and 7-pixel mask at a 5% cut-off. A statistically significant difference was found between the image quality processed with 5 and 7-pixel mask at P=0.00528. The identified optimal mask size to produce a good smooth image was found to be 7 pixels. The best mask size for the John-Sen Lee filter was found to be 7×7 pixels, which yielded Tc-methylene diphosphonate bone scan images with the highest acceptable smoothness.

Utility of a questionnaire tool (QUARAS) for localizing and lateralizing seizures in the epilepsy monitoring unit (EMU).

OBJECTIVES: An accurate description of the seizure semiology improves the recognition of the ictal onset zone and helps in hypothesizing the possible epileptogenic zone (EZ). Semiology based on a reliable description of seizures may be as good as investigative modalities, as has been shown by numerous studies. The main objective of this study was to apply a questionnaire-tool for auras and semiology (QUARAS) in refractory epilepsy cohort and compare its yield to that of standard history-taking. METHODS: A drug refractory epilepsy cohort of 139 subjects was selected, based on inclusion and exclusion criteria. All subjects underwent routine history-taking, and a structured interview with QUARAS (in Hindi language) about 3-6 months later when they were admitted for pre-surgical work-up (Video-EEG, MRI, SPECT and PET), by an epilepsy nurse. Seizures were localised and lateralised at the each step separately, in a blinded manner; concordance with the final hypothesis was checked, after the epilepsy-surgery case-conference, and statistical significance of the difference calculated. RESULTS: Auras were reported in significantly more number of patients after administration of QUARAS (p<0.001); there was also higher concordance between the final hypothesis and the localization and lateralization based on QUARAS than an unstructured history (p<0.001). CONCLUSION: Administering a structured questionnaire in the native language of patients by trained personnel leads to better localisation and lateralisation and may help arrive at a hypothesis about the EZ.

Endoscopic-Assisted (Through a Mini Craniotomy) Corpus Callosotomy Combined With Anterior, Hippocampal, and Posterior Commissurotomy in Lennox-Gastaut Syndrome: A Pilot Study to Establish Its Safety and Efficacy.

BACKGROUND: Corpus callosotomy is a palliative procedure especially for Lennox-Gastaut semiology without localization with drop attacks. OBJECTIVE: To describe endoscopic-assisted complete corpus callosotomy combined with anterior, hippocampal, and posterior commissurotomy. METHODS: Patients with drug refractory epilepsy having drop attacks as the predominant seizure type, bilateral abnormalities on imaging, and moderate to severe mental retardation were included. All underwent a complete workup (including magnetic resonance imaging). RESULTS: Patients (n = 16, mean age 11.4 ± 6.4 years, range 6-19 years) had a mean seizure frequency of 24.5 ± 19.8/days (range 1-60) and a mean intelligence quotient of 25.23 ± 10.71. All had syndromic diagnosis of Lennox-Gastaut syndrome, with the following etiologies: hypoxic insult (10), lissencephaly (2), bilateral band heterotropia (2), and microgyria and pachygyria (2). Surgery included complete callosotomy and the section of anterior and posterior commissure by microscopic approach through a mini craniotomy (11) and endoscopic-assisted approach (5). Complications included meningitis (1), hyperammonemic encephalopathy (2), and acute transient disconnection (5). There was no mortality or long-term morbidity. Mean follow-up was 18 ± 4.7 months (range 16-27 months). Drop attacks stopped in all. Seizure frequency/duration decreased >90% in 10 patients and >50% in 5 patients, and increased in 1 patient. All patients attained presurgical functional levels in 3 to 6 months. Child behavior checklist scores showed no deterioration. Parental questionnaires reported 90% satisfaction attributed to the control of drop attacks. The series was compared retrospectively with an age/sex-matched cohort (where a callosotomy only was performed), and showed better outcome for drop attacks (P < .003). CONCLUSION: This preliminary study demonstrated the efficacy and safety of complete callosotomy with anterior, hippocampal, and posterior commissurotomy in Lennox-Gastaut syndrome (drop attacks) with moderate to severe mental retardation.

Diuretic radionuclide renography in assessing Anderson-Hynes pyeloplasty in unilateral pelviureteric junction obstruction.

The topic of whether improvement can be expected after pyeloplasty in patients with pelvi-ureteric junction obstruction (PUJO) continues to generate debate. The aim of this study was to analyse the functional outcome of unilateral Anderson-Hynes (A-H) pyeloplasty using differential renal function (DRF) and drainage patterns determined by diuretic radionuclide renography (DRR). A retrospective study was carried out by evaluation of the records of patients who underwent A-H pyeloplasty for unilateral PUJO and reported for a follow up renal dynamic scan between the years 2000 and 2003. A total of 126 patients (93 males and 33 females) aged three months to 40 years had undergone pre-operative and post-operative DRR and were followed for at least six months after operation. For comparison, the renal function prior to and after pyeloplasty was classified into three Groups based on the DRF: Group A: > or = 40% DRF 52 patients, Group B: 20%-39% DRF 65 patients and Group C: < 20% DRF 9 patients. The difference between pre-operative and post-operative DRF in the last follow up study, which ranged from six months to 144 months after operation, was calculated for each patient. To account for an accepted error of measurement, an absolute difference in DRF of more than 5% was considered significant. Improvement in drainage was assessed by the time Tmax 1/2 of the renographic curve. Unpaired t test was applied between Group A and Group B patients. Chi square analysis was applied to estimate the proportion of improvement between Groups A and B. Post-pyeloplasty scans revealed stable renal function in 102 (81%) subjects, while improvement was noticed in 14 (11%) subjects. The remaining 10 (8%) subjects had deterioration in renal function. No improvement in renal function was seen in Group C patients. Our results have shown that in the majority of cases studied, after A-H pyeloplasty renal function remains stable. A-H pyeloplasty applied in patients with preserved DRF and obstruction will result in long term preservation of renal function.