Sanjay Gambhir

Do Healthy Potential Kidney Donors in India Have an Average Glomerular Filtration Rate of 81.4 ml/min?

Background: Until now, a normal reference range for glomerular filtration rate (GFR) in adult Indian potential kidney donors has not been determined and values from a western population are being used as reference. Aim: To determine the reference range of GFR in healthy adult Indian potential kidney donors. Basic Procedures: GFR was measured in 610 (250 male, 360 female, average age 35.16 years) healthy potential kidney donors using the 99mTc-DTPA (diethylenetriamine pentaacetic acid) two-plasma sample method of Russell. Results: The mean body surface area (BSA)-normalized GFR value of a young healthy Indian adult potential kidney donor was calculated as 81.4 ± 19.4 ml/min/1.73 m2 BSA – for males it was 82.3 ± 21.3 ml/min/1.73 m2 BSA and for females 80.8 ± 18.1 ml/min/1.73 m2 BSA. There was no significant difference between derived mean GFR values in males and females with a p value of 0.37. Conclusions: The normal GFR value for the healthy Indian adult potential kidney donor appears to be much lower than the accepted value for a western population. The mean GFR value of a young healthy Indian adult potential kidney donor is 81.4 ± 19.4 ml/min/1.73 m2 BSA, which is significantly different from the normal value of 109–125 ml/min derived from a western population. These findings might be useful in deciding on a suitable kidney donor in an Indian context.

Functional renal reserve capacity in different stages of chronic kidney disease

Aim:  There is conflict in published reports on the extent of availability of the functional renal reserve (RR) in healthy adults and in various stages of chronic kidney disease (CKD). The aim of the present study was to determine the RR in various stages of CKD.

Results of a Prospective Multicenter International Atomic Energy Agency Sentinel Node Trial on the Value of SPECT/CT Over Planar Imaging in Various Malignancies

We aimed to assess the additional value of SPECT/CT over planar lymphoscintigraphy (PI) in sentinel node (SN) detection in malignancies with different lymphatic drainage such as breast cancer, melanoma, and pelvic tumors. Methods: From 2010 to 2013, 1,508 patients were recruited in a multicenter study: 1,182 breast cancer, 262 melanoma, and 64 pelvic malignancies (prostate, cervix, penis, vulva). PI was followed by SPECT/CT 1–3 h after injection of 99mTc-colloid particles. Surgery was performed the same or next day. Results: Significantly more SNs were detected by SPECT/CT for breast cancer (2,165 vs. 1,892), melanoma (602 vs. 532), and pelvic cancer (195 vs. 138), all P < 0.001. The drainage basin mismatch between PI and SPECT/CT was 16.5% for breast cancer, 11.1% for melanoma, and 51.6% for pelvic cancers. Surgical adjustment was 17% for breast cancer, 37% for melanoma, and 65.6% for pelvic cancer. Conclusion: SPECT/CT detected more SNs and changed the drainage territory, leading to surgical adjustments in a considerable number of patients in all malignancies studied but especially in the pelvic cancer group because of this groups deep lymphatic drainage. We recommend SPECT/CT in all breast cancer patients with no SN visualized on PI, all patients with melanoma of the head and neck or trunk, all patients with pelvic malignancies, and those breast cancer and melanoma patients with unexpected drainage on PI.

Metastatic Differentiated Thyroid Carcinoma: Clinicopathological Profile and Outcome in an Iodine Deficient Area

Reports on metastatic differentiated carcinoma in endemic goiter regions are scarce. The aim of this study was to look into the clinicopathological profile and outcome of patients with metastatic differentiated thyroid carcinoma (DTC) of endemic origin. This was a retrospective study of 28 cases of metastatic DTC out of a total of 140 DTC patients managed between 1990 and June 1999. Demographic data, clinicopathological profile, operative and radioiodine ablation therapy details, and follow-up findings were noted. The overall incidence of distant metastases in our series was 20%. Mean age was 48.5 +/- 12.8 years (32.1%patients were < 45 years). Most metastases were detected synchronously (85.7%) and were multiple, with the skeletal system being the commonly affected site. Out of 22 cases having skeletal metastases, 6 patients were young (< 45 years). Though most patients with skeletal metastases had follicular carcinoma (FTC), 4 cases had papillary thyroid cancer (PTC). Near total or total thyroidectomy was done in 26 cases. Sixteen patients required regional lymph node dissection. Resection of metastases was performed in 9 cases. Histopathological diagnosis was PTC, FTC, and poorly differentiated carcinoma in 32.1%, 50.0%, and 17.9% of cases, respectively. Most patients had good symptomatic palliation following administration of I131 therapy. In 17.9% of cases there were locoregional recurrences. There was an overall 28.6% mortality. Two patients expired in the perioperative period. Six others died in follow-up (all within 3-9 months). In contrast to iodine sufficient regions, the incidence of metastases was high; the majority of cases had synchronous, symptomatic skeletal metastases. Skeletal metastases were not infrequent even in cases of PTC and in young patients. One-third of the cases were young. Though survival was poor despite aggressive management, significant symptomatic palliation could be achieved in most cases.

Imaging in extrapulmonary tuberculosis

Tuberculosis (TB) remains a major global public health problem, with 1.5 million deaths annually worldwide. One in five cases of TB present as extrapulmonary TB (EPTB), posing major diagnostic and management challenges. Mycobacterium tuberculosis adapts to a quiescent physiological state and is notable for its complex interaction with the host, producing poorly understood disease states ranging from latent infection to active clinical disease. New tools in the diagnostic armamentarium are urgently required for the rapid diagnosis of TB and monitoring of TB treatments, and to gain new insights into pathogenesis. The typical and atypical imaging features of EPTB are reviewed herein, and the roles of several imaging modalities for the diagnosis and management of EPTB are discussed.

Newborn screening for congenital hypothyroidism, galactosemia and biotinidase deficiency in Uttar Pradesh, India

ObjectiveTo assess feasibility and recall rates for newborn screening for congenital hypothyroidism, galactosemia and biotinidase deficiency in a predominantly rural and inner city population in and around the City of Lucknow in Uttar Pradesh, India.DesignProspective observational study.SettingTwo tertiary-care and 5 district hospitals in and around Lucknow.ParticipantsAll babies born in above hospitals during the study period.MethodsHeel prick samples were collected after 24 hours of life. Dried blood spot TSH, total galactose and biotinidase were assayed by immunofluorometry. Age related cut-offs were applied for recall for TSH. For galactosemia and biotinidase deficiency, manufacturer-suggested recall cut-offs used initially were modified after analysis of initial data.Main outcome measureRecall rate for hypothyroidism, galactosemia and biotinidase deficiency.ResultsScreening was carried out for 13426 newborns, 73% of all deliveries. Eighty-five percent of those recalled for confirmatory sampling responded. Using fixed TSH cut off of 20 mIU/L yielded high recall rate of 1.39%, which decreased to 0.84% with use of age-related cut-offs. Mean TSH was higher in males, and in low birth weight and vaginally delivered babies. Eleven babies had congenital hypothyroidism. Recall rates with modified cut-offs for galactosemia and biotinidase deficiency were 0.32% and 0.16%, respectively.ConclusionAn outreach program for newborn screening can be successfully carried out in similar socio-cultural settings in India. For hypothyroidism, the high recall rate due to early discharge was addressed by age-related cut-offs.

Factors Predicting Improvement of Renal Function After Pyeloplasty in Pediatric Patients: A Prospective Study

PURPOSE We assessed the specific preoperative sonographic and urinary factors that may be important in predicting renal function outcomes after pyeloplasty. MATERIALS AND METHODS We prospectively studied 52 consecutive patients with ureteropelvic junction obstruction who underwent pyeloplasty at our tertiary care center between September 2009 and January 2011. Mean ± 2 SD patient age was 4.26 years (range 3 months to 18 years), and minimum followup was 6 months. Preoperative ultrasound findings recorded were pelvic anteroposterior diameter, pelvic cortical thickness, pelvic volume and pelvic cortical ratio. Spot urine protein-to-creatinine ratio from the renal pelvis and bladder was measured intraoperatively. Based on changes in differential renal function on diuretic renogram, patients were divided into 3 groups. Group 1 had stable differential renal function with less than 5% change, group 2 had improved differential renal function greater than 5% and group 3 had deterioration of differential renal function greater than 5%. Data were analyzed using SPSS®, version 17 with cross-tabulation, nonparametric tests and logistic regression. RESULTS On ultrasound only anteroposterior diameter (p = 0.018) and pelvic cortical ratio (p = 0.038) were significantly different among the 3 groups. Difference in bladder sample protein-to-creatinine ratio was not significant (p = 0.69), while pelvic urine protein-to-creatinine ratio was significant (p = 0.001). Anteroposterior diameter, pelvic protein-to-creatinine ratio and pelvic cortical ratio were less than 50 mm, 0.5 and 15, respectively, in all patients with improved renal function. CONCLUSIONS Sonographic and urinary biochemical parameters may predict improvement in renal function after pyeloplasty. Pelvic anteroposterior diameter, pelvic cortical ratio and pelvic urine protein-to-creatinine ratio are the most useful parameters.

Utility of single photon emission computed tomography perfusion scans in radiation treatment planning of locally advanced lung cancers

Purpose: Lung perfusion scan provides a map of the spatial distribution of lung perfusion. This can be used to design radiation portals to spare functional lung (FL), potentially reducing lung toxicity. The purpose of this study was to assess the utility of lung perfusion single photon emission computed tomography (SPECT) in treatment planning for lung cancer patients. Materials and Methods: Radiotherapy treatment planning computed tomography (CT) scans and SPECT scans of 11 patients of lung cancer suitable for external radiotherapy were co-registered. Conventional treatment plans (anatomic plan) and plans with FL information (functional plan) was generated. The difference in dose volume parameters (V20, V30 and mean lung doses) due to these two plans were compared using Bland-Altman plots. Results: Functional plans produced a more favorable plan compared with anatomic plan in all except three cases. FL V20 values and FL mean lung dose were reduced for all patients by an average of 5.45 Gy and 7.72 Gy respectively which were statistically significant. Conclusions: Lung perfusion scans provide functional information which is not provided by CT scans. SPECT-guidance aids in reducing the dose delivered to highly perfused regions which could reduce the incidence of pneumonitis.

A study to improve the image quality in low-dose computed tomography (SPECT) using filtration

Background: The output of the X-ray tube used in computed tomography (CT) provides a spectrum of photon energies. Low-energy photons are preferentially absorbed in tissue; the beam spectrum shifts toward the higher energy end as it passes through more tissue, thereby changing its effective attenuation coefficient and producing a variety of artifacts (beam-hardening effects) in images. Filtering of the beam may be used to remove low-energy photon component. The accuracy of attenuation coefficient calculation by bilinear model depends highly upon accuracy of Hounsfield units. Therefore, we have made an attempt to minimize the beam-hardening effects using additional copper filter in the X-ray beam. The quantitative evaluation were made to see the effect of additional filters on resulting CT images. Materials and Methods: This study was performed on dual-head SPECT (HAWKEYE 4, GE Healthcare) with low-dose CT which acquires images at peak voltages of 120/140 kV and a tube current of 2.5 mA. For the evaluation of image quality, we used CT QA Phantom (PHILIPS) having six different density pins of Water, Polyethylene, Nylon (Aculon), Lexan, Acrylic (Perspex) and Teflon. The axial images were acquired using copper filters of various thicknesses ranging from 1 to 5 mm in steps of 1 mm. The copper filter was designed in such a manner that it fits exactly on the collimator cover of CT X-ray tube. Appropriate fixation of the copper filter was ensured before starting the image acquisition. As our intention was only to see the effect of beam hardening on the attenuation map, no SPECT study was performed. First set of images was acquired without putting any filter into the beam. Then, successively, filters of different thicknesses were placed into the beam and calibration of the CT scanner was performed before acquiring the images. The X-ray tube parameters were kept the same as that of unfiltered X-ray beam. All the acquired image sets were displayed using Xeleris 2 (GE Healthcare) on a high-resolution monitor. Moreover, Jaszaks SPECT Phantom after removing the spheres was used to see the different contrast intensities by inserting the different contrast materials of iodine and bismuth in water as background media. Images were analyzed for visibility, spatial resolution and contrast. Results: Successive improvement in the image quality was noticed when we increased the filter thickness from 1 to 3 mm. The images acquired with 3-mm filter appeared almost with no artifacts and were visibly sharper. Lower energy photons from X-ray beam cause a number of artifacts, especially at bone–tissue interfaces. Additional filtrations removed lower energy photons and improved the image quality. Degradation in the image quality was noticed when we increased the filter thickness further to 4 and 5 mm. This degradation in image quality happened due to reduced photon flux of the resulting X-ray beam, causing high statistical noise. The spatial resolution for image matrix of 512 × 512 was found to be 1.29, 1.07, 0.64 and 0.54 mm for without filter, with 1, 2 and 3 mm filters, respectively. The image quality was further analyzed for signal-to-noise ratio (SNR). It was found to be 1.72, 1.78, 1.98 and 1.99 for open, with 1, 2 and 3 mm filters respectively. This shows that 3-mm filter results in an improvement of 15.7% in SNR. Conclusion: On the basis of this study, we could conclude that use of 3-mm copper filter in the X-ray beam is optimal for removing the artifacts without causing any significant reduction in the photon flux of the resulting X-ray beam. We also propose that as artifacts have been removed from the images, the value of Hounsfield units will be more accurate and hence the value of attenuation coefficients lead to better contrast and visualization of SPECT images.

Preoperative contrast-enhanced computerized tomography should not delay radioiodine ablation in differentiated thyroid carcinoma patients.

BACKGROUND There is concern about potential interference of iodinated contrast used in contrast-enhanced computerized tomography (CECT) with radioiodine therapy in differentiated thyroid carcinoma (DTC). The aim of this study was to determine the effect of iodinated contrast on urinary iodine concentration (UIC) in patients having thyroidectomy compared with control groups without CECT and without thyroidectomy. METHODS This prospective control study consisted of 4 groups each comprising 32 patients. Group 1- DTC patients undergoing preoperative CECT, group 2- DTC patients not undergoing CECT, group 3- benign goiter patients undergoing preoperative CECT, and group 4- patients with non-thyroidal diseases undergoing preoperative CECT. Spot UIC before CECT, after surgery (5-7 d), and at follow-up (4-6 wk) were compared among the groups. RESULTS The median basal UIC levels were not significantly different between the four groups (232.2 versus 263.9 versus 268.2 versus 178.2 μg/L, respectively, P = 0.443). In contrast, groups having preoperative CECT had significantly higher UIC levels at discharge (924 versus 329 versus 776 versus 661 μg/L, respectively, P = 0.001). These differences became insignificant at follow-up (225 versus 252 versus 310 versus 275 μg/L, respectively, P = 0.505). Patients having follow-up UIC values above the conventional cut-off of clinically relevant iodine excess (>200 μg/L) also had significantly higher basal values than those having lower follow-up values (283.0 versus 181.7 μg/L; P = 0.037). CONCLUSIONS Irrespective of the fact whether a patient is thyroidectomized or not preoperative CECT using non-lipophilic contrast does not result in long-term iodine retention.