Sidhartha Nagala - Academia.edu (original) (raw)

Papers by Sidhartha Nagala

Magnetic Resonance in Medicine, May 20, 2015

Ultrasound-guided fine needle aspirate cytology fails to diagnose many malignant thyroid nodules;... more Ultrasound-guided fine needle aspirate cytology fails to diagnose many malignant thyroid nodules; consequently, patients may undergo diagnostic lobectomy. This study assessed whether textural analysis (TA) could noninvasively stratify thyroid nodules accurately using diffusion-weighted MRI (DW-MRI). Methods: This multi-institutional study examined 3T DW-MRI images obtained with spin echo echo planar imaging sequences. The training data set included 26 patients from Cambridge, United Kingdom, and the test data set included 18 thyroid cancer patients from Memorial Sloan Kettering Cancer Center (New York, New York, USA). Apparent diffusion coefficients (ADCs) were compared over regions of interest (ROIs) defined on thyroid nodules. TA, linear discriminant analysis (LDA), and feature reduction were performed using the 21 MaZda-generated texture parameters that best distinguished benign and malignant ROIs. Results: Training data set mean ADC values were significantly different for benign and malignant nodules (P ¼ 0.02) with a sensitivity and specificity of 70% and 63%, respectively, and a receiver operator characteristic (ROC) area under the curve (AUC) of 0.73. The LDA model of the top 21 textural features correctly classified 89/94 DW-MRI ROIs with 92% sensitivity, 96% specificity, and an AUC of 0.97. This algorithm correctly classified 16/18 (89%) patients in the independently obtained test set of thyroid DW-MRI scans. Conclusion: TA classifies thyroid nodules with high sensitivity and specificity on multi-institutional DW-MRI data sets. This method requires further validation in a larger prospective study.

Endocrinology, diabetes & metabolism, Feb 24, 2021

BackgroundUltrasound‐guided fine‐needle aspiration cytology is the gold standard for investigatin... more BackgroundUltrasound‐guided fine‐needle aspiration cytology is the gold standard for investigating thyroid nodules. Stratifying the Thy3 thyroid nodule risk of malignancy is essential for clinical decision‐making. According to the Royal College of Pathologists Guidance (2016), the rate of malignancy for Thy3a is 5–15% and for Thy3f 15–30%. Our aim was to investigate the malignancy rate and the initial management of Thy3 nodules in our institution.MethodsA retrospective review was undertaken of 115 patients with Thy3 cytology results from thyroid fine‐needle aspirations performed between January 2015 and June 2020 at a single centre. A total of 90 out of 115 patients underwent surgery.ResultsOf the 90 patients, we had a 40% malignant rate (36/90). Specifically, 14 of 34 (41.1%) Thy3a and 22 of 56 (39.2%) Thy3f nodules were malignant. Of the malignant lesions, 52.7% (19/36) were follicular thyroid carcinoma. 58.8% (10/17) of male patients and 35.6% (26/73) of female patients had a malignant histology. Eighteen patients eventually needed a completion thyroidectomy.ConclusionCompared with national data, we showed a higher risk of malignancy in Thy3 nodules in our centre. Our study should encourage other centres to audit their own data. We propose setting up a national Thy3 registry as a basis to promote research in improving preoperative diagnosis of indeterminate thyroid nodules.

British Journal of Radiology, Aug 1, 2013

Single-shot diffusion-weighted (DW) echo planar imaging (EPI), which is commonly used for imaging... more Single-shot diffusion-weighted (DW) echo planar imaging (EPI), which is commonly used for imaging the thyroid, is characterised by severe blurring and distortion. The objectives of this work were: 1, to show that a reduced-field of view (r-FOV) DW EPI technique can improve image quality; and 2, to investigate the effect of different reconstruction strategies on the resulting apparent diffusion coefficients (ADCs). Methods: We implemented a single-shot, r-FOV DW EPI technique with a two-dimensional radiofrequency excitation pulse for DW imaging of the thyroid at 3T. Images were reconstructed using root sum of squares (SOS) and an optimal-B 1 reconstruction (OBR). Phantom and in vivo experiments were performed to compare r-FOV and conventional full-FOV DW EPI with root SOS and OBR. Results: r-FOV with OBR substantially improved image quality at 3T. In phantoms, r-FOV gave more accurate ADCs than full-FOV. In vivo r-FOV always gave lower ADC values with respect to the full-FOV technique irrespective of the reconstruction used and whether only two or multiple b-values were used to compute the ADCs. Conclusion: r-FOV DW EPI can reduce image blurring and distortion at the expense of a low signal-to-noise ratio. OBR is a promising reconstruction technique for accurate ADC measurements in lower signal-to-noise ratio regimes, although further studies are needed to characterise its performance.

Journal of Laryngology and Otology, Jan 6, 2010

British Journal of Surgery

Aim Zenker diverticulum can cause significant dysphagia and surgery is the definitive management.... more Aim Zenker diverticulum can cause significant dysphagia and surgery is the definitive management. NICE guidelines describe inadequate evidence on laser cricopharyngeal myotomy (CPM). This study aimed to assess the safety and efficacy of carbon dioxide laser and stapling CPM to treat Zenker diverticulum. Method Retrospective data was collected from patients who underwent endoscopic CPM at the Royal Berkshire Hospital between 2011 and 2021. Two cohorts were assigned: endoscopic laser (EL) or endoscopic stapling (ES). Primary outcomes evaluated safety. These were surgical complication rates, duration of inpatient stay, readmissions, barium swallow leak and considered case complexity (revision cases). The secondary outcomes, persistence or recurrence of symptoms evaluated efficacy. Results One-hundred and eight patients (mean [range] age 75 [38 – 95] yr, 71 (66%) men, 23 (21%) revision surgeries) underwent CPM. The EL (n = 76) cohort had two (2.63%) surgical complications (mucosal tear ...

Proceedings of the 32nd ACM International Conference on Information and Knowledge Management

Radiologists have an important task of diagnosing thyroid nodules present in ultra sound images. ... more Radiologists have an important task of diagnosing thyroid nodules present in ultra sound images. Although reporting systems exist to aid in the diagnosis process, these systems do not provide explanations about the diagnosis results. We present ThyExp-a web based toolkit for it use by medical professionals, allowing for accurate diagnosis with explanations of thyroid nodules present in ultrasound images utilising artificial intelligence models. The proposed web-based toolkit can be easily incorporated into current medical workflows, and allows medical professionals to have the confidence of a highly accurate machine learning model with explanations to provide supplementary diagnosis data. The solution provides classification results with their probability accuracy, as well as the explanations in the form of presenting the key features or characteristics that contribute to the classification results. The experiments conducted on a real-world UK NHS hospital patient dataset demonstrate the effectiveness of the proposed approach. This toolkit can improve the trust of medical professional to understand the confidence of the model in its predictions. This toolkit can improve the trust of medical professionals in understanding the models reasoning behind its predictions.

Key Points Primary and recurrent/residual Pharyngeal Pouches up to 3cm can be safely treated with... more Key Points Primary and recurrent/residual Pharyngeal Pouches up to 3cm can be safely treated with Endoscopic LASER division with primary mucosal repair Primary mucosal repair after Pharyngeal Pouch division using LASER may make Endoscopic LASER pharyngeal pouch surgery safer than cases where it is not undertaken. There is no significant difference in the number of complications for patients treated with Endoscopic LASER surgery vs Endoscopic Stapling The modal duration of inpatient stay for patients treated with Endoscopic LASER surgery with primary mucosal repair is 2 days, as opposed to 1 day for Endoscopic Stapling surgery Post-operative IV antibiotics, Nasogastric feeding, antiemetics are helpful in reducing adverse effects from Endoscopic LASER surgery for Pharyngeal Pouches

British Journal Of Criminology, 2022

Throughout the last thirty years bushfires or wildfires have increased globally with devastating ... more Throughout the last thirty years bushfires or wildfires have increased globally with devastating impacts on ecosystems, human habitats and greenhouse gas emissions. The recording of unprecedented temperatures coupled with the warming of international oceans, and the melting of polar icecaps from anthropocentric climate change are major contributors to the increase of global wildfires that are forecasted to worsen unless urgent political intervention reduces greenhouse gas emissions. The state and corporate actors that enable widespread toxic emissions have been referred to as ‘climate criminals’ within discourses of ecocide and green criminology. This article adopts a green criminological lens to the emerging concept of ‘ecocide’ to examine political leaders and their mismanagement of devastating bushfires. Through a detailed interrogation of Australia’s Royal Commission into National Natural Disaster Arrangements it traces the devastating Summer events of 2019/2020 and concludes th...

British Journal of Surgery

The parathyroid glands are at risk of injury during thyroid, parathyroid and other central compar... more The parathyroid glands are at risk of injury during thyroid, parathyroid and other central compartment neck surgery. Accidental removal or devascularisation of the glands can lead to hypocalcaemia and potentially a need for lifelong calcium supplementation. Traditional approaches to parathyroid preservation include meticulous surgical technique to identify, separate, and preserve the parathyroid glands. However, up to 23.5% of patients experience transient hypocalcaemia after thyroidectomy, and 3.6% remain on calcium supplements at 6 months (1). At parathyroid surgery, inability or difficulty in identifying abnormal parathyroid glands and differentiating them from thyroid nodules, lymph nodes and brown adipose tissue is a cause of failure to cure hyperparathyroidism. This may lead to extensive exploration and potentially damage to normal parathyroid glands. In recent years, there has been increasing interest in intraoperative techniques that can improve parathyroid identification an...

Magnetic Resonance in Medicine, 2015

ICASSP 2022 - 2022 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP)

British Journal of Surgery, 2022

Introduction Iodine-131 is an effective treatment for thyrotoxicosis. In 2019, the National Insti... more Introduction Iodine-131 is an effective treatment for thyrotoxicosis. In 2019, the National Institute for Clinical Excellence (NICE) guidelines suggested offering radioactive iodine as first-line definitive treatment for adults with Graves’ disease, toxic nodular and multinodular goitre unless it is unsuitable or anti-thyroid drugs are likely to achieve remission. The aim of this study was to evaluate the clinical outcome one year after using fixed dose Iodine-131 for hyperthyroidism and to identify any associated factors. Methods Electronic patient records were studied retrospectively for all patients who were treated with radioiodine therapy for hyperthyroidism between July 2017 and March 2020 at a district general hospital in the UK. Response to radioiodine therapy was assessed at 6 and 12 months by a dedicated thyroid nurse-led virtual follow-up. Results We identified 67 patients with a mean age of 55.9 years (range 18–84); 48 (72%) females, 19 (28%) males. Of these, 57 (85%) pa...

Endocrinology, Diabetes & Metabolism, 2021

Ultrasound‐guided fine‐needle aspiration cytology is the gold standard for investigating thyroid ... more Ultrasound‐guided fine‐needle aspiration cytology is the gold standard for investigating thyroid nodules. Stratifying the Thy3 thyroid nodule risk of malignancy is essential for clinical decision‐making. According to the Royal College of Pathologists Guidance (2016), the rate of malignancy for Thy3a is 5–15% and for Thy3f 15–30%. Our aim was to investigate the malignancy rate and the initial management of Thy3 nodules in our institution.

Irish Journal of Medical Science (1971 -)

Magnetic Resonance in Medicine, 2015

Purpose: Ultrasound-guided fine needle aspirate cytology fails to diagnose many malignant thyroid... more Purpose: Ultrasound-guided fine needle aspirate cytology fails to diagnose many malignant thyroid nodules; consequently, patients may undergo diagnostic lobectomy. This study assessed whether textural analysis (TA) could noninvasively stratify thyroid nodules accurately using diffusion-weighted MRI (DW-MRI).

The British Journal of Radiology, Jun 14, 2013

Single-shot diffusion-weighted (DW) echo planar imaging (EPI), which is commonly used for imaging... more Single-shot diffusion-weighted (DW) echo planar imaging (EPI), which is commonly used for imaging the thyroid, is characterised by severe blurring and distortion. The objectives of this work were: 1, to show that a reduced-field of view (r-FOV) DW EPI technique can improve image quality; and 2, to investigate the effect of different reconstruction strategies on the resulting apparent diffusion coefficients (ADCs). We implemented a single-shot, r-FOV DW EPI technique with a two-dimensional radiofrequency excitation pulse for DW imaging of the thyroid at 3T. Images were reconstructed using root sum of squares (SOS) and an optimal-B1 reconstruction (OBR). Phantom and in vivo experiments were performed to compare r-FOV and conventional full-FOV DW EPI with root SOS and OBR. r-FOV with OBR substantially improved image quality at 3T. In phantoms, r-FOV gave more accurate ADCs than full-FOV. In vivo r-FOV always gave lower ADC values with respect to the full-FOV technique irrespective of the reconstruction used and whether only two or multiple b-values were used to compute the ADCs. r-FOV DW EPI can reduce image blurring and distortion at the expense of a low signal-to-noise ratio. OBR is a promising reconstruction technique for accurate ADC measurements in lower signal-to-noise ratio regimes, although further studies are needed to characterise its performance. DW imaging of the thyroid at 3T could potentially benefit from r-FOV acquisition strategies, such as the r-FOV DW EPI technique proposed in this paper.

Bulletin of The Royal College of Surgeons of England, 2014

Journal of Molecular Biology, 2001

Magnetic Resonance in Medicine, May 20, 2015

Endocrinology, diabetes & metabolism, Feb 24, 2021

British Journal of Radiology, Aug 1, 2013

Journal of Laryngology and Otology, Jan 6, 2010

British Journal of Surgery

Proceedings of the 32nd ACM International Conference on Information and Knowledge Management

British Journal Of Criminology, 2022

British Journal of Surgery

Magnetic Resonance in Medicine, 2015

ICASSP 2022 - 2022 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP)

British Journal of Surgery, 2022

Endocrinology, Diabetes & Metabolism, 2021

Irish Journal of Medical Science (1971 -)

Magnetic Resonance in Medicine, 2015

The British Journal of Radiology, Jun 14, 2013

Single-shot diffusion-weighted (DW) echo planar imaging (EPI), which is commonly used for imaging... more Single-shot diffusion-weighted (DW) echo planar imaging (EPI), which is commonly used for imaging the thyroid, is characterised by severe blurring and distortion. The objectives of this work were: 1, to show that a reduced-field of view (r-FOV) DW EPI technique can improve image quality; and 2, to investigate the effect of different reconstruction strategies on the resulting apparent diffusion coefficients (ADCs). We implemented a single-shot, r-FOV DW EPI technique with a two-dimensional radiofrequency excitation pulse for DW imaging of the thyroid at 3T. Images were reconstructed using root sum of squares (SOS) and an optimal-B1 reconstruction (OBR). Phantom and in vivo experiments were performed to compare r-FOV and conventional full-FOV DW EPI with root SOS and OBR. r-FOV with OBR substantially improved image quality at 3T. In phantoms, r-FOV gave more accurate ADCs than full-FOV. In vivo r-FOV always gave lower ADC values with respect to the full-FOV technique irrespective of the reconstruction used and whether only two or multiple b-values were used to compute the ADCs. r-FOV DW EPI can reduce image blurring and distortion at the expense of a low signal-to-noise ratio. OBR is a promising reconstruction technique for accurate ADC measurements in lower signal-to-noise ratio regimes, although further studies are needed to characterise its performance. DW imaging of the thyroid at 3T could potentially benefit from r-FOV acquisition strategies, such as the r-FOV DW EPI technique proposed in this paper.

Bulletin of The Royal College of Surgeons of England, 2014

Journal of Molecular Biology, 2001