Publications by authors named "Chandan J Das"

95 Publications

Imaging of Coronavirus Disease 2019 Infection From Head to Toe: A Primer for the Radiologist.

Curr Probl Diagn Radiol 2021 Jul 5. Epub 2021 Jul 5.

Department of Radiodiagnosis, All India Institute of Medical Sciences, New Delhi, India. Electronic address:

Coronavirus Disease 2019 (COVID-19) disease has rapidly spread around the world after initial identification in Wuhan, China, in December 2019. Most common presentation is mild or asymptomatic disease, followed by pneumonia, and rarely- multiorgan failure and Acute Respiratory Distress Syndrome (ARDS). Knowledge about the pathophysiology, imaging and treatment of this novel virus is rapidly evolving due to ongoing worldwide research. Most common imaging modalities utilized during this pandemic are chest radiography and HRCT with findings of bilateral peripheral, mid and lower zone GGO and/or consolidation, vascular enlargement and crazy paving. HRCT is also useful for prognostication and follow-up of severely ill COVID-19 patients. Portable radiography allows follow-up of ICU patients & obviates the need of shifting critically ill patients and disinfection of CT room. As the pandemic has progressed, numerous neurologic manifestations have been described in COVID-19 including stroke, white matter hyperintensities and demyelination on MRI. Varying abdominal presentations have been described, which on imaging either show evidence of COVID-19 pneumonia in lung bases or show abdominal findings including bowel thickening and vascular thrombosis. Numerous thrombo-embolic and cardiovascular complications have also been described in COVID-19 including arterial and venous thrombosis, pulmonary embolism and myocarditis. It is imperative for radiologists to be aware of all the varied faces of this disease on imaging, as they may well be the first physician to suspect the disease. This article aims to review the multimodality imaging manifestations of COVID-19 disease in various organ systems from head to toe.
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http://dx.doi.org/10.1067/j.cpradiol.2021.06.015DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8256677PMC
July 2021

Imaging Spectrum of Female Genital Tuberculosis: A Comprehensive Review.

Curr Probl Diagn Radiol 2021 Jul 6. Epub 2021 Jul 6.

Department of Radiology, All India Institute of Medical Sciences (AIIMS), New Delhi, India.

Female genital tuberculosis is a relatively uncommon form of extrapulmonary tuberculosis that is under-reported and under-recognized. The early course of the disease has fewer manifestations, resulting in late presentation with grave complications like infertility and ectopic pregnancy. Also, difficulty in isolation of the causative bacteria further delays the diagnosis. The radiologist should be well versed with imaging findings of female genital TB to help the clinicians to initiate prompt treatment. This review shall cover imaging findings of female genital TB involving fallopian tubes, uterus, ovaries, cervix, vagina, and vulva on different imaging modalities. Fallopian tubes are almost always involved in genital TB followed by uterus and ovaries. Hysterosalpingogram and ultrasound can best detect tubercular changes in fallopian tubes and uterus whereas cross-sectional imaging is essential for the diagnosis of ovarian or peritoneal TB as they closely mimic malignancy. Cervical, vaginal, or vulval TB produces nonspecific changes and histopathological diagnosis is required for confirmation of the diagnoses. Close differential diagnosis on imaging like malignancy or pelvic inflammatory disease, are also discussed with a brief discussion of the pathogenesis.
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http://dx.doi.org/10.1067/j.cpradiol.2021.06.014DOI Listing
July 2021

Imaging of Kaposi sarcoma.

Abdom Radiol (NY) 2021 Jul 13. Epub 2021 Jul 13.

Department of Abdominal Imaging, The University of Texas MD Anderson Cancer Center, 1400 Pressler St, Houston, TX, 77030, USA.

Kaposi sarcoma (KS) is a form of cancer that primarily appears on the skin but can potentially involve internal organs. There are several types of KS. The purpose of this article is to discuss the manifestations of KS and their appearance on imaging, the differential diagnoses associated with these findings, and molecular markers associated with KS that can aid appropriate diagnosis and therapy.
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http://dx.doi.org/10.1007/s00261-021-03205-6DOI Listing
July 2021

Utility of first order MRI-Texture analysis parameters in the prediction of histologic grade and muscle invasion in urinary bladder cancer: a preliminary study.

Br J Radiol 2021 Jun 29;94(1122):20201114. Epub 2021 Apr 29.

Departments of Radiology, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, India.

Objective: To explore the utility of first-order MRI-texture analysis (TA) parameters in predicting histologic grade and muscle invasion in urinary bladder cancer (UBC).

Methods: After ethical clearance, 40 patients with UBC, who were imaged on a 3.0-Tesla scanner, were retrospectively included. Using the TexRAD platform, two readers placed freehand ROI on the sections demonstrating the largest dimension of the tumor, evaluating only one tumor per patient. Interobserver reproducibility was assessed using the intraclass correlation coefficient (ICC). Mann-Whitney test and ROC curve analysis were used to identify statistical significance and select parameters with high class separation capacity (AUC >0.8), respectively. Pearson's test was used to identify redundancy in the results.

Results: All texture parameters showed excellent ICC. The best parameters in differentiating high and low-grade tumors were mean/ mean of positive pixels (MPP) at SSF 0 (AUC: 0.897) and kurtosis at SSF 5 (AUC: 0.828) on the ADC images. In differentiating muscle invasive from non-muscle invasive tumors, mean/ MPP at SSF 0 on the ADC images showed AUC >0.8; however, this finding resulted from the confounding effect of high-grade histology on the ADC values of muscle invasive tumors.

Conclusion: MRI-TA generated few parameters which were reproducible and useful in predicting histologic grade. No independent parameters predicted muscle invasion.

Advances In Knowledge: There is lacuna in the literature concerning the role of MRI-TA in the prediction of histologic grade and muscle invasion in UBC. Our study generated a few first-order parameters which were useful in predicting high-grade histology.
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http://dx.doi.org/10.1259/bjr.20201114DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8173695PMC
June 2021

Unveiling the confusion in renal fusion anomalies: role of imaging.

Abdom Radiol (NY) 2021 09 3;46(9):4254-4265. Epub 2021 Apr 3.

Department of Radiology, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, 110029, India.

Renal fusion anomalies are common congenital anomalies of the urogenital tract and have their genesis in the early embryonic period. They are classified into partial fusion anomalies (e.g., crossed fused ectopia, and horseshoe kidney) and complete fusion anomalies (e.g., fused pelvic kidney). Horseshoe kidney is the most common renal fusion anomaly and is characterized by the presence of two distinct functioning kidneys on either side of the vertebral column, with fusion occurring at the inferior poles in majority of the cases. Crossed fused ectopia is characterized by the presence of an ectopic kidney that crosses the midline and fuses with the orthotopic contralateral kidney, whereas fused pelvic (pancake) kidney is a complete fusion anomaly characterized by extensive medial fusion of both kidneys in the pelvis. Fusion anomalies are often associated with abnormalities of renal rotation, migration, and vascular supply, which predispose the kidneys to a number of complications and create difficulty during retroperitoneal surgeries and interventions. They are also associated with other congenital abnormalities of the urogenital tract, gastrointestinal tract, cardiovascular system, and skeletal system. Hence, a thorough understanding of the etiopathogenesis and radiological features of fusion anomalies is important for directing patient management. This review summarizes the embryological basis, clinical presentation and imaging approach to renal fusion anomalies, followed by detailed anatomical and radiological description of the morphological types, and the complications associated with these anomalies.
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http://dx.doi.org/10.1007/s00261-021-03072-1DOI Listing
September 2021

Clinical Value of Patient-Specific Three-Dimensional Printing of Kidney Before Partial Nephrectomy: A Qualitative Assessment.

J Endourol 2021 Sep 16;35(9):1405-1410. Epub 2021 Aug 16.

Department of Urology and All India Institute of Medical Sciences, New Delhi, India.

To qualitatively assess the clinical usefulness of patient-specific high-fidelity three-dimensional (3D) print model of kidney before partial nephrectomy (PN) and to identify subset domains where it may help in clinical terms. Thirteen 3D models were printed for tumors having RENAL nephrometry score of ≥8. Their usage for PN was assessed prospectively using a qualitative questionnaire to be answered on a Likert scale of 1-10. The questions focused on realistic resemblance, preoperative dry surgical run, intertest comparison, surgical impact, and overall beneficence domains as perceived by primary surgeons with respect to surgical conduct during PN. Mean RENAL score was 9.15 (8-11). Models were rated high (9.07 ± 0.86) for realistic resemblance domain and were rated better than contrast-enhanced computed tomography (CECT) (8.38 ± 0.87) and intraoperative ultrasonography (8.07 ± 1.26) for orientation regarding resection margins. A further marginal improvement to 8.2 ± 0.84 was noted against ultrasound where surgeon did a dry cut preoperatively. Use of superselective arterial approach in four, precise awareness about dissection of a major vessel in four, retroperitoneoscopic approach in one, and surgical margin awareness in three were directly attributed to the model. Overall utility of having a model printed was rated high (8.23 ± 1.3). The 3D print models of complex renal tumors have high realistic resemblance to actual patient's anatomy. They were rated better than preoperative CECT or intraoperative ultrasonography for orientation regarding surgical resection margins. It may also help change or modify the surgical plan in a subset of patients with a potential to improve overall outcomes in these complex cases.
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http://dx.doi.org/10.1089/end.2020.1103DOI Listing
September 2021

Characterisation of prostate cancer using texture analysis for diagnostic and prognostic monitoring.

NMR Biomed 2021 06 27;34(6):e4495. Epub 2021 Feb 27.

Centre for Biomedical Engineering, Indian Institute of Technology Delhi, New Delhi, India.

Automated classification of significant prostate cancer (PCa) using MRI plays a potential role in assisting in clinical decision-making. Multiparametric MRI using a machine-aided approach is a better step to improve the overall accuracy of diagnosis of PCa. The objective of this study was to develop and validate a framework for differentiating Prostate Imaging-Reporting and Data System version 2 (PI-RADS v2) grades (grade 2 to grade 5) of PCa using texture features and machine learning (ML) methods with diffusion-weighted imaging (DWI) and apparent diffusion coefficient (ADC). The study cohort included an MRI dataset of 59 patients with clinically proven PCa. Regions of interest (ROIs) for a total of 435 lesions were delineated from the segmented peripheral zones of DWI and ADC. Six texture methods comprising 98 texture features in total (49 each of DWI and ADC) were extracted from lesion ROIs. Random forest (RF) and correlation-based feature selection methods were applied on feature vectors to select the best features for classification. Two ML classifiers, support vector machine (SVM) and K-nearest neighbour, were used and validated by 10-fold cross-validation. The proposed framework achieved high diagnostic performance with a sensitivity of 85.25% ± 3.84%, specificity of 95.71% ± 1.96%, accuracy of 84.90% ± 3.37% and area under the receiver-operating characteristic curve of 0.98 for PI-RADS v2 grades (2 to 5) classification using the RF feature selection method and Gaussian SVM classifier with combined features of DWI + ADC. The proposed computer-assisted framework can distinguish between PCa lesions with different aggressiveness based on PI-RADS v2 standards using texture analysis to improve the efficiency of PCa diagnostic performance.
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http://dx.doi.org/10.1002/nbm.4495DOI Listing
June 2021

Pulmonary infections after renal transplantation: a prospective study from a tropical country.

Transpl Int 2021 03 26;34(3):525-534. Epub 2021 Feb 26.

Department of Nephrology, All India Institute of Medical Sciences, New Delhi, India.

Pulmonary infection is a leading cause of morbidity and mortality in renal transplant recipients. In a prospective study, we characterized their epidemiology in a tropical country with high infectious disease burden. Adult renal transplant recipients presenting with pulmonary infections from 2015 to 2017 were evaluated using a specific diagnostic algorithm. 102 pulmonary infections occurred in 88 patients. 32.3% infections presented in the first year, 31.4% between 1 and 5, and 36.3% beyond 5 years after transplantation. Microbiological diagnosis was established in 69.6%, and 102 microorganisms were identified. Bacterial infection (29.4%) was most common followed by tuberculosis (23.5%), fungal (20.6%), Pneumocystis jiroveci (10.8%), viral (8.8%), and nocardial (6.9%) infections. Tuberculosis(TB) and bacterial infections presented throughout the post-transplant period, while Pneumocystis (72.7%), cytomegalovirus (87.5%) and nocardia (85.7%) predominantly presented after >12 months. Fungal infections had a bimodal presentation, between 2 and 6 months (33.3%) and after 12 months (66.7%). Four patients had multi-drug resistant(MDR) TB. In 16.7% cases, plain radiograph was normal and infection was diagnosed by a computed tomography imaging. Mortality due to pulmonary infections was 22.7%. On multivariate Cox regression analysis, use of ATG (HR-2.39, 95% CI: 1.20-4.78, P = 0.013), fungal infection (HR-2.14, 95% CI: 1.19-3.84, P = 0.011) and need for mechanical ventilation (9.68, 95% CI: 1.34-69.82, P = 0.024) were significant predictors of mortality in our patients. To conclude, community-acquired and endemic pulmonary infections predominate with no specific timeline and opportunistic infections usually present late. Nocardiosis and MDR-TB are emerging challenges.
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http://dx.doi.org/10.1111/tri.13817DOI Listing
March 2021

Imaging spectrum of pulmonary infections in renal transplant patients.

Indian J Radiol Imaging 2020 Jul-Sep;30(3):273-279. Epub 2020 Oct 15.

Department of Radiology, AIIMS, Ansari Nagar, New Delhi, India.

In the post renal transplant setting, pulmonary infections comprise an important set of complications. Microbiological diagnosis although specific is often delayed and insensitive. Radiography is the most common and first imaging test for which patient is referred, however it is relatively insensitive. HRCT is a very useful imaging tool in the scenario where radiography is negative or inconclusive and high clinical suspicion for infection is present. HRCT features vary among the various pathogens and also depend on the level of immunocompromise. Certain HRCT findings are characteristic for specific pathogens and may help narrow diagnosis. In this review article, we will summarize the imaging findings of various pulmonary infections encountered in post renal transplant patients.
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http://dx.doi.org/10.4103/ijri.IJRI_357_19DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7694710PMC
October 2020

Male genital tract tuberculosis: A comprehensive review of imaging findings and differential diagnosis.

Abdom Radiol (NY) 2021 04 12;46(4):1677-1686. Epub 2020 Oct 12.

Department of Radiology, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, 110029, India.

Urogenital tuberculosis is the most common form of extrapulmonary tuberculosis. Genital organ involvement occurs as a continuum of urinary tract tuberculosis and often presents a diagnostic challenge due to the non-specific nature of the symptoms. Delay in diagnosis may lead to complications such as infertility and perineoscrotal sinuses. Imaging plays an important role in raising timely suspicion of tuberculosis. In this article, we describe the imaging findings of male genital tuberculosis and the differential diagnosis. High-resolution ultrasonography (HRUS) is the best modality for assessing the epididymis, testis, scrotum and vas deferens, whereas MRI is optimal for evaluating the prostate, seminal vesicles and ejaculatory ducts. Epididymis is the most common site of genital tuberculosis, and presents as a nodular lesion limited to the tail or as diffuse enlargement. The proximal vas deferens is also frequently involved due to anatomical contiguity and shows diffuse or nodular thickening. Advanced cases may show pyocele formation and scrotal wall sinuses. Testicular involvement is almost always secondary to epididymal tuberculosis and presents as single or multiple nodules, diffuse enlargement, or the 'miliary' pattern. Isolated testicular involvement should raise suspicion of malignancy. Tuberculosis of the prostate is often asymptomatic. The most common imaging manifestations are nodules and the diffuse forms, which may later evolve into abscesses. Fibrosis and calcification occur with healing. Seminal vesicle and ejaculatory duct involvement with fibrosis may cause infertility. Awareness of the imaging findings would enable the radiologist to raise timely suspicion, so that prompt treatment is initiated and complications are prevented.
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http://dx.doi.org/10.1007/s00261-020-02811-0DOI Listing
April 2021

Is there a utility of adding skeletal imaging to 68-Ga-prostate-specific membrane antigen-PET/computed tomography in initial staging of patients with high-risk prostate cancer?

Nucl Med Commun 2020 Nov;41(11):1183-1188

Diagnostic Nuclear Medicine Division, Department of Nuclear Medicine, All India Institute of Medical Sciences, New Delhi, India.

Purpose: Both bone-scan and cross-sectional imaging are indicated in the staging of high-risk prostate cancer (PCa). However, 68Ga-prostate-specific membrane antigen (PSMA)-PET/computed tomography (CT) has proven to be an excellent tracer for detection of skeletal metastases. The aim of this study was to assess if adding skeletal imaging (with 18F-Fluoride-PET/CT) to 68-Ga-PSMA-PET/CT had any impact on high-risk PCa staging.

Method: Fifty treatment-naive, histopathologically proven, high-risk (European Association of Urology) PCa patients underwent both 68-Ga-PSMA-PET/CT and 18F-Fluoride-PET/CT for staging.

Results: Fluoride-PET/CT detected significantly a higher number of skeletal metastases/patient than PSMA-PET/CT (median 4.5/patient vs 3.0; Wilcoxan-signed-rank-test, P = 0.060) and there was a significantly higher proportion of only Fluoride-avid than only PSMA-avid lesions (McNemar-test P < 0.001). No significant advantage was seen in patient-wise metrics. Most lesions missed by PSMA-PET/CT were in flat bones (25/33). serum prostate specific antigen (S.PSA) showed positive correlation with both, the number of lesions [r(PSMA)-0.555 (P = 0.006) and r(Fluoride)-0.622 (P = 0.001)] as well as tumor to background ratio (TBR) [[r-0.706 (P < 0.001) and 0.516 (P = 0.010)]. Median TBR was significantly higher in PSMA-PET/CT (22.77 vs 16.30; P < 0.001). All three patients with only Fluoride-avid lesions (also not identified in bone-scan) showed biochemical response with additional therapy.

Conclusion: Though, Fluoride-PET/CT detected a higher absolute number of lesions than PSMA-PET/CT, no significant advantage was seen in patient-wise metrics. Fluoride-PET/CT added second-line management in only 3/50 patients, which could have been reduced to 1/50, with more sensitive evaluation of flat bones in PSMA-PET-CT. Therefore, additional skeletal imaging is not needed with 68-Ga-PSMA-PET/CT in initial staging of high-risk PCa.
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http://dx.doi.org/10.1097/MNM.0000000000001268DOI Listing
November 2020

MRI-Targeted Prostate Biopsy: What Radiologists Should Know.

Korean J Radiol 2020 09;21(9):1087-1094

Department of Radiology, University of Cincinnati Medical Center, Cincinnati, OH, USA.

Transrectal ultrasound (TRUS)-guided systematic biopsy, the current gold standard for the detection of prostate cancer, suffers from low sensitivity for clinically significant cancer. The use of diagnostic multiparametric MRI has increased the relevance of targeted biopsy techniques such as MRI-TRUS fusion biopsy and direct (in-bore) MRI-guided biopsy, which have higher detection rate for clinically significant cancer. Although primarily used in patients who remain at high clinical suspicion for prostate cancer despite a negative systematic biopsy, with the increasing use of upfront diagnostic MRI, these biopsies are expected to replace routine systematic biopsies. This pictorial essay aims to enhance our understanding of the concepts of these biopsy techniques so that they can be performed safely and provide maximum diagnostic yield.
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http://dx.doi.org/10.3348/kjr.2019.0817DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7371617PMC
September 2020

Comparison of Contrast-Enhanced CT + CT Enterography and 68Ga-DOTANOC PET/CT in Gastroenteropancreatic Neuroendocrine Tumors.

Clin Nucl Med 2020 Nov;45(11):848-853

From the Departments of Nuclear Medicine.

Background: Increase in incidence of neuroendocrine tumors (NETs) has been attributed in part to the availability of sensitive diagnostic modalities, such as Ga-DOTA-peptide PET/CT. However, it suffers from problems such as obscurement of tracer-avid lesions by physiological gut activity and collapsed gut lumen. Contrast-enhanced CT and CT enterography (CTE) do not have these drawbacks.

Purpose: The aim of this study was to compare the diagnostic performances of contrast-enhanced CT + CTE and the Ga-DOTA-peptide PET/noncontrast CT in GEP-NETs.

Methods: Fifty-six patients (mean age, 57.8 ± 13.3 years [male:female, 1.95:1]), with histopathologically proven gastroenteropancreatic NETs, who had undergone both Ga-DOTANOC-PET/NCCT (60 minutes, post-IV injection of 111-185 MBq) and contrast-enhanced CT (CECT) + CTE (using 1.5-2 L isotonic mannitol solution and 1-2 mg/kg of IV contrast), were retrospectively selected. Twenty-three patients had been referred for identification of primary lesions and 33 for staging/restaging. The scans were independently evaluated by 2 blinded physicians, who documented the number and site of lesions, with reporting confidence (3 = high confidence, 2 = equivocal confidence, 1 = low confidence). Reference standard was created using clinical, biochemical, and imaging parameters (ie, uptake and contrast enhancement), along with corroboration from previous or follow-up scans. Finally, PET images coregistered to the CECT + CTE were independently evaluated for any additional benefit.

Results: The numbers of primary lesions detected by CECT + CTE and PET/CT were 69 and 57, respectively. Lesion-wise sensitivities for patients with unknown primary in CECT + CTE and PET/CT were 57.7% (95% confidence interval [CI], 39.0%-74.5%) and 71.4% (95% CI, 52.9%-84.7%), respectively. Corresponding numbers in patients who had come for staging/restaging were 73.2% (95% CI, 58.1%-84.3%) and 73.8% (95% CI, 58.9%-84.7%). Lesions missed in CECT + CTE were gastrointestinal (n = 14), lymph nodes (n = 25), mesenteric (n = 1), and pancreatic (n = 7), whereas corresponding numbers for PET/CT were 14, 5, 3, and 2. Contrast-enhanced CT + CTE showed more false-positives (n = 26) than PET/CT (n = 9). Lesions missed by CECT + CTE were smaller than detected lesions (median, 9.7 mm [interquartile range, 7.5-31.1] vs 17.7 mm [interquartile range, 12.2-30.0]; P = 0.062), and lesions missed by PET had significantly lower tumor/background (liver) SUVmax ratio (median, 1.3 [interquartile range, 0.6-3.8] vs 4.7 [interquartile range, 2.7-10.8]). The ratio of true-positives to false-positives dropped markedly, when reporting confidence in CECT + CTE was low (4/15 [for rating 1 or 2] vs 93/11 [rating 3]). Corresponding numbers for PET/CT were (40/7 [for rating 1 or 2] vs 80/2 [rating 3]). Combination of these 2 modalities would have increased the lesion-wise sensitivities in patients with unknown primaries to 89.7% (95% CI, 73.6%-96.4%) and the confidence rating of soft tissue lesions to predominantly high (134 lesions rated 3, and 10 rated 1 or 2).

Conclusions: PET/CT is a sensitive modality for staging and restaging well-differentiated NETs. Use of CECT + CTE as a complementary modality in patients with uncertain uptake or high clinical suspicion of gastroenteropancreatic NETs should be considered, as it improves the lesion detection and reporting confidence.
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http://dx.doi.org/10.1097/RLU.0000000000003188DOI Listing
November 2020

Segmentation of prostate zones using probabilistic atlas-based method with diffusion-weighted MR images.

Comput Methods Programs Biomed 2020 Nov 2;196:105572. Epub 2020 Jun 2.

Centre for Biomedical Engineering, Indian Institute of Technology Delhi, New Delhi, India; Department of Biomedical Engineering, All India Institute of Medical Sciences, New Delhi, India. Electronic address:

Background And Objective: Accurate segmentation of prostate and its zones constitute an essential preprocessing step for computer-aided diagnosis and detection system for prostate cancer (PCa) using diffusion-weighted imaging (DWI). However, low signal-to-noise ratio and high variability of prostate anatomic structures are challenging for its segmentation using DWI. We propose a semi-automated framework that segments the prostate gland and its zones simultaneously using DWI.

Methods: In this paper, the Chan-Vese active contour model along with morphological opening operation was used for segmentation of prostate gland. Then segmentation of prostate zones into peripheral zone (PZ) and transition zone (TZ) was carried out using in-house developed probabilistic atlas with partial volume (PV) correction algorithm. The study cohort included MRI dataset of 18 patients (n = 18) as our dataset and methodology were also independently evaluated using 15 MRI scans (n = 15) of QIN-PROSTATE-Repeatability dataset. The atlas for zones of prostate gland was constructed using dataset of twelve patients of our patient cohort. Three-fold cross-validation was performed with 10 repetitions, thus total 30 instances of training and testing were performed on our dataset followed by independent testing on the QIN-PROSTATE-Repeatability dataset. Dice similarity coefficient (DSC), Jaccard coefficient (JC), and accuracy were used for quantitative assessment of the segmentation results with respect to boundaries delineated manually by an expert radiologist. A paired t-test was performed to evaluate the improvement in zonal segmentation performance with the proposed PV correction algorithm.

Results: For our dataset, the proposed segmentation methodology produced improved segmentation with DSC of 90.76 ± 3.68%, JC of 83.00 ± 5.78%, and accuracy of 99.42 ± 0.36% for the prostate gland, DSC of 77.73 ± 2.76%, JC of 64.46 ± 3.43%, and accuracy of 82.47 ± 2.22% for the PZ, and DSC of 86.05 ± 1.50%, JC of 75.80 ± 2.10%, and accuracy of 91.67 ± 1.56% for the TZ. The segmentation performance for QIN-PROSTATE-Repeatability dataset was, DSC of 85.50 ± 4.43%, JC of 75.00 ± 6.34%, and accuracy of 81.52 ± 5.55% for prostate gland, DSC of 74.40 ± 1.79%, JC of 59.53 ± 8.70%, and accuracy of 80.91 ± 5.16% for PZ, and DSC of 85.80 ± 5.55%, JC of 74.87 ± 7.90%, and accuracy of 90.59 ± 3.74% for TZ. With the implementation of the PV correction algorithm, statistically significant (p<0.05) improvements were observed in all the metrics (DSC, JC, and accuracy) for both prostate zones, PZ and TZ segmentation.

Conclusions: The proposed segmentation methodology is stable, accurate, and easy to implement for segmentation of prostate gland and its zones (PZ and TZ). The atlas-based segmentation framework with PV correction algorithm can be incorporated into a computer-aided diagnostic system for PCa localization and treatment planning.
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http://dx.doi.org/10.1016/j.cmpb.2020.105572DOI Listing
November 2020

Hemodialysis in Infants: Challenges and New Paradigms.

J Vasc Interv Radiol 2020 05;31(5):787

Cardiovascular and Interventional Radiology, All India Institute of Medical Sciences, New Delhi 110029, India.

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http://dx.doi.org/10.1016/j.jvir.2020.02.011DOI Listing
May 2020

PET/CT in Evaluation of Low Backache Due to Sacral Nerve Root Involvement: Inflammatory and Malignant Involvement.

Clin Nucl Med 2020 Jun;45(6):e299-e300

From the Departments of Nuclear Medicine.

Low back pain with radiation to lower limbs is due to nerve root impingement or involvement in most cases. F-FDG PET/CT has shown sacral nerve root involvement in several peripheral nerve pathologies, including neurolymphomatosis, peripheral nerve sheath tumor, and plexopathies. We present 2 cases of a low back pain with ulcerative colitis and metastatic neuroendocrine tumor who underwent F-FDG PET/CT and Ga-DOTANOC PET/CT, respectively. PET/CT can be used as an adjunct tool to evaluate sacral nerve root involvement to look for malignant or inflammatory nerve involvement.
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http://dx.doi.org/10.1097/RLU.0000000000003021DOI Listing
June 2020

Iodine Parameters in Triple-Bolus Dual-Energy CT Correlate With Perfusion CT Biomarkers of Angiogenesis in Renal Cell Carcinoma.

AJR Am J Roentgenol 2020 04 18;214(4):808-816. Epub 2020 Feb 18.

All authors: Department of Radiology, All India Institute of Medical Sciences, Ansari Nagar, New Delhi 110029, India.

The purpose of this study is to determine the degree of the relationship between perfusion CT (PCT) parameters and iodine concentration metrics derived from triple-bolus dual-energy CT (DECT) and to compare the radiation dose delivered. This single-center prospective study was conducted from October 2015 to September 2017. Twenty-three consenting adults (15 men and eight women; mean [± SD] age, 56 ± 13 years [range, 25-78 years]) with renal cell carcinomas underwent consecutive PCT and triple-bolus DECT examinations. Triple-bolus DECT consisted of synchronous corticomedullary, nephrographic, and delayed phase scans acquired using a dual-source DECT scanner. Two readers independently analyzed blood flow, blood volume, and permeability, as measured by PCT, and iodine density and iodine ratio, as measured by triple-bolus DECT. Size-specific dose estimates were calculated for both groups. Interreader agreement was good for permeability (intraclass correlation coefficient [ICC] =.812) and blood flow (ICC = 0.849) and excellent for blood volume (ICC = 0.956), iodine density (ICC = 0.961), and iodine ratio (ICC = 0.956). Very strong positive correlations were found between blood volume and iodine density ( < 0.001) and between blood volume and iodine ratio ( < 0.001). Strong positive correlations were found between blood flow and iodine density ( < 0.001) and between blood flow and iodine ratio ( < 0.001). The correlations between permeability and iodine density ( = 0.01) and between permeability and iodine ratio ( = 0.02) were moderate. The mean size-specific dose estimate of triple-bolus DECT was approximately 15 times lower than that of PCT ( < 0.001). Quantitative iodine metrics derived from triple-bolus DECT showed significant correlation with CT parameters in renal cell carcinoma, with a significantly lower radiation dose.
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http://dx.doi.org/10.2214/AJR.19.21969DOI Listing
April 2020

Prostate MRI-TRUS fusion biopsy: a review of the state of the art procedure.

Abdom Radiol (NY) 2020 07;45(7):2176-2183

Department of Radiology, University of Cincinnati Medical Center, ML 0761, 234 Goodman Street, Cincinnati, OH, 45267-0761, USA.

Prostate cancer is the fourth most common cancer and population-based screening programmes are being increasingly adopted worldwide. Screening-positive patients undergo routine transrectal ultrasound (TRUS)-guided systematic biopsy, which is the current diagnostic standard for prostate cancer. However, systematic biopsies suffer from poor sensitivity, especially for the tumors of the anterior prostate and apex as well as in large volume glands. In the past decade, MRI-guided targeted biopsies have come up, which utilize the multiparametric capability of MRI to target lesions for sampling. MRI/TRUS fusion biopsies combine the advantages of MRI-targeting with that of real-time guidance made possible by TRUS. MRI-TRUS fusion biopsies are being increasingly used in men with high clinical suspicion of prostate cancer who have had prior negative systematic biopsies. A large number of fusion biopsy platforms are currently available commercially. Although the basic workflow is similar, there are differences in the operational software, biopsy routes offered, TRUS acquisition technique, type of correction applied at the time of fusion and in the probe tracking hardware. The article describes the current role and indications of MRI-TRUS fusion biopsy followed by a discussion on the workflow, patient preparation, biopsy procedure and complications.
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http://dx.doi.org/10.1007/s00261-019-02391-8DOI Listing
July 2020

Urinary diversions: a primer of the surgical techniques and imaging findings.

Abdom Radiol (NY) 2019 12;44(12):3906-3918

Cincinnati Veterans Hospital, University of Cincinnati Medical Center, 234 Goodman Street, Cincinnati, OH, 45267, USA.

Objective: The article attempts to describe the indications, classification, and surgical anatomy of the commonly performed urinary diversion procedures, followed by the imaging protocol and radiological appearances of the normal postoperative anatomy and complications related to these procedures.

Contents: Diversion procedures are used to reroute urine after cystectomy and in patients with refractory neurogenic or outlet obstruction of the urinary bladder. Broadly, these can be classified as continent and incontinent diversions. Patients with urinary diversions frequently undergo radiological investigations for the detection of complications. Commonly, a loopogram or pouchogram is performed few weeks after the surgery to look for leak, whereas CT or MRI is used for long-term follow-up. Postoperative complications can be early (within 30 days of the surgery) or delayed and include leaks, collections, strictures, calculi, parastomal hernia, small bowel obstruction, and oncologic recurrence.

Conclusion: A variety of urinary diversion procedures are commonly performed and interpretation of the postsurgical anatomy can be overwhelming for the general radiologist. This article provides a basic understanding of the normal anatomy as well as a thorough discussion on the imaging protocol and radiological appearances of the potential complications associated with these procedures.
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http://dx.doi.org/10.1007/s00261-019-02179-wDOI Listing
December 2019

Multiple abscesses in a renal transplant recipient.

Kidney Int 2019 08;96(2):526

Department of Nephrology, All India Institute of Medical Sciences, New Delhi, India.

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http://dx.doi.org/10.1016/j.kint.2019.02.005DOI Listing
August 2019

Effect of combination and number of b values in IVIM analysis with post-processing methodology: simulation and clinical study.

MAGMA 2019 Oct 18;32(5):519-527. Epub 2019 Jun 18.

Centre for Biomedical Engineering, Indian Institute of Technology Delhi, Hauz Khas, New Delhi, 110016, India.

Objective: To investigate the effect of number and combination of b values used on the accuracy of estimated Intravoxel Incoherent Motion (IVIM) parameters using simulation and clinical data.

Materials And Methods: Simulations with seven combinations of b values were performed for 4, 6, 8, and 13 numbers of b values with six different values of D, D*, and f parameters. Two methodologies were implemented for IVIM analysis: standard biexponential model (BE) and biexponential model with total variation penalty function (BE + TV). Clinical data set of six patients with prostate cancer was retrospectively analyzed using 4, 8, and 13 b values.

Results: BE + TV method showed lesser error and lower variability in simulation and clinical data, respectively. 8 and 13 b values showed good agreement in the values of parameters estimated with high correlation coefficient (ρ = 0.83-0.93). Clinical data showed high spurious noise with lower b values [4 b values leading to high coefficient of variation (CV); however, substantially, lower CV was observed with 8 and 13 b values].

Discussion: BE model with TV penalty function is robust to combination of b values used for IVIM analysis. Combination of 8 b values provided a reasonably good accuracy in IVIM parameters.
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http://dx.doi.org/10.1007/s10334-019-00764-0DOI Listing
October 2019

Prospective analysis of factors predicting feasibility & success of longitudinal intussusception vasoepididymostomy in men with idiopathic obstructive azoospermia.

Indian J Med Res 2019 Jan;149(1):51-56

Department of Urology, All India Institute of Medical Sciences, New Delhi, India.

Background & Objectives: : Microsurgical reconstruction for idiopathic obstructive azoospermia is a challenging procedure, and selection of appropriate patients is important for successful outcomes. This prospective study was done to evaluate the ability of scrotal ultrasound measurements to predict the surgical feasibility and determine factors that could predict a patent anastomosis following vaso-epididymal anastomosis (VE) in men with idiopathic obstructive azoospermia.

Methods: : In this prospective study, men diagnosed with idiopathic obstructive azoospermia, scheduled for a longitudinal intussusception VE, underwent a scrotal ultrasound measurement of testicular and epididymal dimensions. During surgery, site and type of anastomosis, presence of sperms in the epididymal fluid and technical satisfaction with the anastomosis were recorded. All men where VE could be performed were followed up for appearance of sperms in the ejaculate. Ultrasound parameters were compared between men who had a VE versus those with negative exploration. Predictive factors were compared between men with or without a patent anastomosis.

Results: : Thirty four patients were included in the study conducted between September 2014 and August 2016 and a VE was possible in only 19 (55%) patients. Of these 19 patients, six had a patent anastomosis with one pregnancy. Preoperative ultrasound measurements could not identify patients where a VE could not be performed. Motile sperm in the epididymal fluid was the only significant predictor of a successful anastomosis.

Interpretation & Conclusion: : Forty five per cent of men planned for a VE for idiopathic obstructive azoospermia could not undergo a reconstruction. Ultrasound assessment of testicular and epididymal dimensions could not predict the feasibility of performing a VE. The presence of motile sperms in the epididymal fluid was the only significant predictor of a patent VE in our study.
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http://dx.doi.org/10.4103/ijmr.IJMR_1192_17DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6507538PMC
January 2019

Multiparametric magnetic resonance imaging-transrectal ultrasound fusion biopsies increase the rate of cancer detection in populations with a low incidence of prostate cancer.

Investig Clin Urol 2019 05 12;60(3):156-161. Epub 2019 Apr 12.

Department of Urology, All India Institute of Medical Sciences, New Delhi, India.

Purpose: To prospectively evaluate the diagnostic yield of multiparametric magnetic resonance imaging (mpMRI)-fusion, transrectal ultrasound (TRUS)-guided prostate biopsies for detection of prostate cancer in an Asian population with a low incidence of prostate cancer.

Materials And Methods: A total of 131 males with suspected prostate cancer were recruited to undergo fusion biopsy with the Artemis prostate fusion biopsy device (Eigen, Grass Valley, CA, USA). All patients underwent standard 12-core systematic biopsies in addition to biopsies targeted at the mpMRI-identified abnormal regions. Yield from the standard cores was compared with that from the targeted cores. Gleason scores of 4+3 or higher were considered significant.

Results: The mean age of the patients was 63.54±7.96 years and the mean prostate-specific antigen value was 9.75±5.35 ng/mL. A total of 36 patients had cancer, of which 3 (8.3%) were detected only on standard cores and 3 (8.3%) only on targeted cores. Of the clinically significant cancers (n=30), targeted biopsy detected a higher number (28/30, 93.3%) than standard biopsy (21/30, 70.0%). A total of 6 of 8 cancers (75.0%) that were insignificant on standard biopsy were upgraded to significant cancer on targeted cores.

Conclusions: Eight percent of cancers were detected only on MRI-TRUS fusion-targeted biopsies, whereas the method upgraded more than two-thirds of insignificant cancers to significant cancers. Fusion biopsies thus provide incremental information over standard TRUS biopsies in the diagnosis of significant prostate cancer in populations with a low incidence of prostate cancer.
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http://dx.doi.org/10.4111/icu.2019.60.3.156DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6495042PMC
May 2019

Macrodystrophia lipomatosa of the foot.

BMJ Case Rep 2019 May 6;12(5). Epub 2019 May 6.

Department of Radiodiagnosis, All India Institute of Medical Sciences, New Delhi, Delhi, India.

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http://dx.doi.org/10.1136/bcr-2019-229464DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6510147PMC
May 2019

Development of a Method to Determine Electron Density and Effective Atomic Number of High Atomic Number Solid Materials Using Dual-Energy Computed Tomography.

J Med Phys 2019 Jan-Mar;44(1):49-56

Department of Medical Physics Unit, IRCH, AIIMS, New Delhi, India.

Aim: This study aims to develop a method using dual-energy computed tomography (DECT) to determine the effective atomic number and electron density of substances.

Materials And Methods: Ten chemical substances of pure analytical grade were obtained from various manufacturers. These chemicals were pelletized using a hydraulic press. These pellets were scanned using DECT. A relation was obtained for the pellet's atomic number and electron density with their CT number or Hounsfield unit (HU) values. Calibration coefficients were determined. Five new chemical pellets were scanned, and their effective atomic number and electron densities were determined using the calibration coefficients to test the efficacy of the calibration method.

Results: The results obtained for effective atomic number and electron density from the HU number of DECT images were within ±5% and ±3%, respectively, of their actual values.

Conclusions: DECT can be used as an effective tool for determining the effective atomic number and electron density of high atomic number substance.
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http://dx.doi.org/10.4103/jmp.JMP_125_18DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6438052PMC
April 2019

The Case | Mass in nonfunctioning first renal allograft in a recipient of 2 transplant kidneys.

Kidney Int 2019 04;95(4):1001-1002

Department of Nephrology, All India Institute of Medical Sciences, New Delhi, India. Electronic address:

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http://dx.doi.org/10.1016/j.kint.2018.11.017DOI Listing
April 2019

Transfer Dysphagia Due to Focal Dystonia.

J Mov Disord 2018 09 30;11(3):129-132. Epub 2018 Sep 30.

Department of Neurology, All India Institute of Medical Sciences, New Delhi, India.

Objective: The inability to propel a bolus of food successfully from the posterior part of the oral cavity to the oropharynx is defined as transfer dysphagia. The present case series describes the varied presentation of transfer dysphagia due to focal dystonia and highlights the importance of early detection by following up on strong suspicions.

Methods: We describe seven cases of transfer dysphagia due to focal dystonia. Transfer dysphagia as a form of focal dystonia may appear as the sole presenting complaint or may present with other forms of focal dystonia.

Results: Four out of seven patients had pure transfer dysphagia and had previously been treated for functional dysphagia. A high index of suspicion, barium swallow including videofluoroscopy, associated dystonia in other parts of the body and response to drug therapy with trihexyphenidyl/tetrabenazine helped to confirm the diagnosis.

Conclusion: Awareness of these clinical presentations among neurologists and non-neurologists can facilitate an early diagnosis and prevent unnecessary investigations.
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http://dx.doi.org/10.14802/jmd.17081DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6182304PMC
September 2018

Magnetic Resonance Imaging-Transrectal Ultrasound Fusion Biopsy of the Prostate-An Update.

Semin Roentgenol 2018 Jul 5;53(3):219-226. Epub 2018 Apr 5.

Department of Radiology, All India Institute of Medical Sciences (A.I.I.M.S), Ansari Nagar, New Delhi 110029, India.

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http://dx.doi.org/10.1053/j.ro.2018.04.003DOI Listing
July 2018

Thumb Opposition Recovery Following Surgery for Severe Carpal Tunnel Syndrome: A Clinical, Radiological, and Electrophysiological Pilot Study.

J Hand Surg Am 2019 Feb 20;44(2):157.e1-157.e5. Epub 2018 Jun 20.

Department of Orthopaedics, All India Institute of Medical Sciences, New Delhi, India.

Purpose: To objectively assess recovery of thumb opposition in patients with carpal tunnel syndrome (CTS) after open carpal tunnel release and to evaluate electrophysiological and magnetic resonance (MR) neurography findings as predictors of thumb opposition recovery.

Methods: A total of 22 patients with severe CTS and thenar atrophy were included in this study. A detailed clinical, electrophysiological, and MR neurography evaluation was done both before and after surgery at 6 months to assess thumb opposition recovery.

Results: The median duration of symptoms was 12 months (interquartile range, 12-20 months). The compound muscle action potential of the abductor pollisis brevis (CMAP-APB) also showed statistically significant improvement of 0.5 + 0.2 mV after surgery. Tip-tip pulp pinch strength increased from 1.2 ± 0.4 to 2.0 ± 0.4 kg at 6-month follow-up, lateral pulp pinch strength increased from 1.9 ± 0.6 to 2.8 ± 0.9 kg at 6-month follow-up, and 3-point pulp pinch also improved from 1.9 ± 0.5 to 2.8 ± 0.9 at final follow-up. On MR neurogram, the proportion of patients with abnormal median nerve morphology decreased from 81.8% to 68.2%, abnormal thenar branch morphology decreased from 63.6% to 36.4% and denervation edema deceased from 59.1% to 13.6%.

Conclusions: Patients suffering from severe CTS with thenar atrophy and detectable CMAP-APB showed promising improvement following open carpal tunnel release.

Type Of Study/level Of Evidence: Prognostic IV.
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http://dx.doi.org/10.1016/j.jhsa.2018.05.004DOI Listing
February 2019

Gallium-68 DOTA-NOC PET/CT as an alternate predictor of disease activity in sarcoidosis.

Nucl Med Commun 2018 Aug;39(8):768-778

Nuclear Medicine.

Introduction: We evaluated the role of gallium-68-labeled [1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid]-1-Nal3-octreotide (Ga-DOTA-NOC) PET/CT in assessing sarcoidosis disease activity.

Patients And Methods: Patients diagnosed with sarcoidosis underwent Ga-DOTA-NOC-PET/CT. The maximum standardized uptake value (SUVmax) at the pathological site and in the descending thoracic aorta (reference standard, SUVmed) were assessed. A SUVmax/SUVmed ratio (disease activity score) of more than one was considered a marker of active disease and was compared with the clinical symptoms and serum angiotensin-converting enzyme and computed tomography (CT) scan. The primary outcome was to assess the efficacy of the scan in estimating disease activity.

Results: Of the 39 patients enrolled in the study, 27 patients were symptomatic and the rest were asymptomatic at enrollment. Increased disease activity was present in 25 (92%) of the 27 symptomatic patients and two (16%) of the 12 asymptomatic patients. The sensitivity and specificity of the test were 92.5% (95% confidence interval=75.7-99.0) and 83.3% (95% confidence interval=51.5-97.9), respectively. Seven out of nine patients who became asymptomatic after treatment showed a significant decrease in the mean disease activity score in post-treatment scans (3.38±1.05 vs 1.20±0.82, P<0.001).

Conclusion: Ga-DOTA-NOC PET/CT emerged as a useful tool to assess the disease activity and treatment response in patients with sarcoidosis with thoracic involvement.
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http://dx.doi.org/10.1097/MNM.0000000000000869DOI Listing
August 2018
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