Shaheen Dixon
Current Organizations / Institutes
The organizations/institutes from the scholar's latest article
Previous Organizations / Institutes
The organizations / institutes from the scholar's other articles in the past ten years
Research Subjects
Shaheen Dixon has a total of 24 co-authors. Here are the top co-authors by number of shared publications:
- Mark Bratby
The John Radcliffe Hospital
3 shared publications - Raman Uberoi
Department of Radiology, Consultant Interventional Radiologist, Oxford University Hospitals, John Racliffe Hospital, Oxford, UK
2 shared publications - Susan Anthony
John Radcliffe Hospital
2 shared publications - Vivek Shrivastava
Hull Royal Infirmary
2 shared publications C.R. Tapping
1 shared publicationCharles Ross Tapping
Department of Radiology, The John Radcliffe Hospital, Oxford, UK
1 shared publication
Latest Publications
- 15 July 2014
- Published by Springer Nature in CardioVascular and Interventional Radiology
- Vol. 38 (2) , 329-335
Outcome Following a Negative CT Angiogram for Gastrointestinal Hemorrhage
This study was designed to evaluate the role of a negative computed tomography angiogram (CTA) in patients who present with gastrointestinal (GI) hemorrhage. A review of all patients who had CTAs for GI hemorrhage over an 8-year period from January 2005 to December 2012 was performed. Data for patient demographics, location of hemorrhage, hemodynamic stability, and details of angiograms and/or the embolization procedure were obtained from the CRIS/PACS database, interventional radiology database, secure electronic medical records, and patient’s clinical notes. A total of 180 patients had 202 CTAs during the 8-year period: 87 CTAs were performed for upper GI hemorrhage (18 positive for active bleeding, 69 negative) and 115 for lower GI hemorrhage (37 positive for active bleeding, 78 negative); 58.7 % (37/63) of patients with upper GI bleed and 77.4 % (48/62) of patients with lower GI bleed who had an initial negative CTA did not rebleed without the need for radiological or surgical intervention. This difference was statistically significant (p = 0.04). The relative risk of rebleeding, following a negative CTA, in lower GI bleeding versus upper GI bleeding patients is 0.55 (95 % confidence interval 0.32–0.95). Patients with upper GI bleed who had negative CTAs usually require further intervention to stop the bleeding. In contrast, most patients presenting with lower GI hemorrhage who had a negative first CTA were less likely to rebleed.
- 15 July 2014
- Published by Springer Nature in CardioVascular and Interventional Radiology
- Vol. 38 (2) , 329-335
Outcome Following a Negative CT Angiogram for Gastrointestinal Hemorrhage
This study was designed to evaluate the role of a negative computed tomography angiogram (CTA) in patients who present with gastrointestinal (GI) hemorrhage. A review of all patients who had CTAs for GI hemorrhage over an 8-year period from January 2005 to December 2012 was performed. Data for patient demographics, location of hemorrhage, hemodynamic stability, and details of angiograms and/or the embolization procedure were obtained from the CRIS/PACS database, interventional radiology database, secure electronic medical records, and patient’s clinical notes. A total of 180 patients had 202 CTAs during the 8-year period: 87 CTAs were performed for upper GI hemorrhage (18 positive for active bleeding, 69 negative) and 115 for lower GI hemorrhage (37 positive for active bleeding, 78 negative); 58.7 % (37/63) of patients with upper GI bleed and 77.4 % (48/62) of patients with lower GI bleed who had an initial negative CTA did not rebleed without the need for radiological or surgical intervention. This difference was statistically significant (p = 0.04). The relative risk of rebleeding, following a negative CTA, in lower GI bleeding versus upper GI bleeding patients is 0.55 (95 % confidence interval 0.32–0.95). Patients with upper GI bleed who had negative CTAs usually require further intervention to stop the bleeding. In contrast, most patients presenting with lower GI hemorrhage who had a negative first CTA were less likely to rebleed.
- 6 May 2014
- Published by Springer Nature in CardioVascular and Interventional Radiology
- Vol. 38 (2) , 463-469
Radiation Protection Methods for the Interventionalist’s Hands: Use of an Extension Tube
Cumulative radiation exposure to the hands during certain interventional procedures may be high. It is important to decrease the amount of radiation to the operator due to the possibility of deterministic effects. We performed a pilot study to demonstrate a significant decrease in operator dose when using extension tubing (ET) in combination with shielding and collimation during a simulated percutaneous transhepatic cholangiogram (PTC) procedure. A whole body, anthropomorphic phantom was used to simulate the patient. A Unfors-Xi Survey detector (to measure scatter) supported by a retort stand and trolley was placed in various positions to simulate the position of hands and eyes/thyroid of an interventionalist. Radiation dose was measured simulating left and right-sided PTC punctures with and without a lead shield, and with and without ET. Regarding the radiation dose to the hands; the use of an ET reduces dose by 54 % in right-sided PTC punctures without a shield and by 91 % if used in combination with a shield. For left-sided PTC punctures, ET reduces hand dose by 75 %. The use of collimation decreases hand dose by approximately 60 %. The use of shielding reduces dose to the eyes/thyroid by 98 %. The dose to the hands can be significantly reduced with the appropriate use of a shield, ET, and tight collimation. The use of a shield is paramount to reduce dose to the eyes/thyroid. It is important for interventionalists to adhere to radiation protective practice considering the potential deterministic effects during a lifelong career.
- 6 May 2014
- Published by Springer Nature in CardioVascular and Interventional Radiology
- Vol. 38 (2) , 463-469
Radiation Protection Methods for the Interventionalist’s Hands: Use of an Extension Tube
Cumulative radiation exposure to the hands during certain interventional procedures may be high. It is important to decrease the amount of radiation to the operator due to the possibility of deterministic effects. We performed a pilot study to demonstrate a significant decrease in operator dose when using extension tubing (ET) in combination with shielding and collimation during a simulated percutaneous transhepatic cholangiogram (PTC) procedure. A whole body, anthropomorphic phantom was used to simulate the patient. A Unfors-Xi Survey detector (to measure scatter) supported by a retort stand and trolley was placed in various positions to simulate the position of hands and eyes/thyroid of an interventionalist. Radiation dose was measured simulating left and right-sided PTC punctures with and without a lead shield, and with and without ET. Regarding the radiation dose to the hands; the use of an ET reduces dose by 54 % in right-sided PTC punctures without a shield and by 91 % if used in combination with a shield. For left-sided PTC punctures, ET reduces hand dose by 75 %. The use of collimation decreases hand dose by approximately 60 %. The use of shielding reduces dose to the eyes/thyroid by 98 %. The dose to the hands can be significantly reduced with the appropriate use of a shield, ET, and tight collimation. The use of a shield is paramount to reduce dose to the eyes/thyroid. It is important for interventionalists to adhere to radiation protective practice considering the potential deterministic effects during a lifelong career.
- 14 November 2012
- Published by Springer Nature in CardioVascular and Interventional Radiology
- Vol. 36 (4) , 970-977
Is There a Role for Empiric Gastroduodenal Artery Embolization in the Management of Patients with Active Upper GI Hemorrhage?
To assess the relative efficacy of empiric gastroduodenal artery (GDA) embolization in reducing recurrent hemorrhage compared to image-guided targeted embolization. Data were retrospectively collected for consecutive patients who had catheter angiography for major upper gastrointestinal hemorrhage from May 2008 to November 2010 (n = 40). The total number of cases were divided into two main groups according to angiographic findings: those that demonstrated a site of hemorrhage on catheter angiography (group 1, n = 13), and those where the site of hemorrhage was not identified on catheter angiography (group 2, n = 27). Group 2 was then further divided into patients who received empiric embolization (group 2a, n = 20) and those who had no embolization performed after angiography (group 2b, n = 7). The technical and clinical success rates for embolization in groups 1 and 2a were, respectively, 100 vs. 95 %, and 85 vs. 80 %. There was no statistical significance in the recurrent hemorrhage rate, reintervention rate, or 30 day mortality between targeted and empiric embolization groups. There were no complications attributed to embolization within this study cohort. Cases of duodenal-related major upper gastrointestinal hemorrhage where no embolization is performed have poor outcome. Empiric embolization of the GDA in patients with major upper gastrointestinal hemorrhage refractory to endoscopic treatment appears to be a safe and effective treatment, with low reintervention rates and good clinical outcome comparable to patients where the site of hemorrhage is localized and embolized with computed tomographic angiography or catheter angiography and embolized.
- 14 November 2012
- Published by Springer Nature in CardioVascular and Interventional Radiology
- Vol. 36 (4) , 970-977
Is There a Role for Empiric Gastroduodenal Artery Embolization in the Management of Patients with Active Upper GI Hemorrhage?
To assess the relative efficacy of empiric gastroduodenal artery (GDA) embolization in reducing recurrent hemorrhage compared to image-guided targeted embolization. Data were retrospectively collected for consecutive patients who had catheter angiography for major upper gastrointestinal hemorrhage from May 2008 to November 2010 (n = 40). The total number of cases were divided into two main groups according to angiographic findings: those that demonstrated a site of hemorrhage on catheter angiography (group 1, n = 13), and those where the site of hemorrhage was not identified on catheter angiography (group 2, n = 27). Group 2 was then further divided into patients who received empiric embolization (group 2a, n = 20) and those who had no embolization performed after angiography (group 2b, n = 7). The technical and clinical success rates for embolization in groups 1 and 2a were, respectively, 100 vs. 95 %, and 85 vs. 80 %. There was no statistical significance in the recurrent hemorrhage rate, reintervention rate, or 30 day mortality between targeted and empiric embolization groups. There were no complications attributed to embolization within this study cohort. Cases of duodenal-related major upper gastrointestinal hemorrhage where no embolization is performed have poor outcome. Empiric embolization of the GDA in patients with major upper gastrointestinal hemorrhage refractory to endoscopic treatment appears to be a safe and effective treatment, with low reintervention rates and good clinical outcome comparable to patients where the site of hemorrhage is localized and embolized with computed tomographic angiography or catheter angiography and embolized.
- 1 September 2012
- Published by Elsevier in Clinical Radiology
- Vol. 67 (9) , 923-931
The role of interventional radiology and imaging in pancreatic islet cell transplantation
- 1 September 2012
- Published by Elsevier in Clinical Radiology
- Vol. 67 (9) , 923-931
The role of interventional radiology and imaging in pancreatic islet cell transplantation
- 1 April 2012
- Published by SAGE Publications in Acta Radiologica
- Vol. 53 (3) , 292-295
Successful fibroid embolization of pelvic and inferior mesenteric artery collaterals after previous uterine artery embolization
A 47-year-old woman with a history of myomectomies and uterine artery embolization 15 years previously presented with increasing menorrhagia and dysmenorrhea. Magnetic resonance imaging (MRI) demonstrated multiple enhancing fibroids, extensive uterine supply from what appeared to be patent uterine arteries, and significant supply from what appeared to be the left ovarian artery. Aortography demonstrated no ovarian supply, but extensive collateral supply from distal branches of the inferior mesenteric artery (IMA), with further collateral supply from the anterior division of both internal iliac arteries. There was no filling of the uterine arteries distal to the coils. Embolization was performed with technical and clinical success. This case highlights the potential for recruitment of collateral vessels following coil embolization and is the first reported case of successful fibroid embolization from distal IMA branches.
- 1 April 2012
- Published by SAGE Publications in Acta Radiologica
- Vol. 53 (3) , 292-295
Successful fibroid embolization of pelvic and inferior mesenteric artery collaterals after previous uterine artery embolization
A 47-year-old woman with a history of myomectomies and uterine artery embolization 15 years previously presented with increasing menorrhagia and dysmenorrhea. Magnetic resonance imaging (MRI) demonstrated multiple enhancing fibroids, extensive uterine supply from what appeared to be patent uterine arteries, and significant supply from what appeared to be the left ovarian artery. Aortography demonstrated no ovarian supply, but extensive collateral supply from distal branches of the inferior mesenteric artery (IMA), with further collateral supply from the anterior division of both internal iliac arteries. There was no filling of the uterine arteries distal to the coils. Embolization was performed with technical and clinical success. This case highlights the potential for recruitment of collateral vessels following coil embolization and is the first reported case of successful fibroid embolization from distal IMA branches.