Patrick D Mc Laughlin

University of British Columbia | UBC · Department of Radiology

The aim was to assess the performance of low-dose non-contrast CT of the urinary tract (LD-CT) acquired at radiation exposures close to that of abdominal radiography using adaptive statistical iterative reconstruction (ASiR). Thirty-three patients with clinically suspected renal colic were prospectively included. Conventional dose (CD-CT) and LD-CT...

The principal advantages of dual-energy computed tomography (CT) over conventional CT in the musculoskeletal setting relate to the additional information provided regarding tissue composition, artifact reduction, and image optimization. This article discusses the manifestations of these in clinical practice-urate and bone marrow edema detection, me...

The aim of this article is to inform and update emergency radiologists in respect of the clinically relevant benefits that dual-energy computed tomography (CT) contributes over conventional single-energy CT in the emergency setting using practical imaging examples. Particular emphasis will be placed on acute gout, bone marrow edema, acute renal col...

Background Opinions seem somewhat divided when considering the effect of artificial intelligence (AI) on medical imaging. The aim of this study was to characterise viewpoints presented online relating to the impact of AI on the field of radiology and to assess who is engaging in this discourse. Methods Two search methods were used to identify onli...

UNSTRUCTURED Diagnostic Reference Levels (DRLs) are used to establish if local imaging protocols have been optimised. This study examines a modern multi-detector 64 slice CT (MDCT) system for four commonly performed examinations in a large tertiary care centre by comparison with current international reference standards. Effective dose (ED) was cal...

Background Computed tomography (CT), by its nature, imparts a high dose of ionising radiation to patients being imaged. Diagnostic Reference Levels (DRLs) are used extensively in research but are also used in practice to establish if local imaging protocols have been optimised. Aim To audit effective dose (ED) at CT for four commonly performed exa...

Purpose: The purpose of this study was to evaluate the clinical utility of temporal resolution optimization (TR-Opt), a computed tomography (CT) postprocessing technique, in reducing aortic motion artifacts in blunt thoracic trauma patients. Materials and methods: This was an IRB-approved study of 61 patients with blunt thoracic trauma carried o...

Purpose: To evaluate the role of virtual monoenergetic imaging (VMI) in the detection of peritoneal metastatic disease in contrast-enhanced computed tomography (CT) of the abdomen and pelvis and to compare this technique to the conventional 120 kV mixed dataset. Materials and methods: Institutional review board approval was obtained with no info...

Purpose It is uncertain whether patients with elevated troponin and non-classical presentation of acute coronary syndrome (ACS) should receive coronary CT angiography (CCTA). A proportion of these patients will have no coronary artery disease (CAD) and would benefit from non-invasive investigations and expedited discharge. Objectives were to determ...

Purpose: To retrospectively compare the image noise, signal-to-noise ratio (SNR), and subjective image quality between CT images acquired with a dual-source, split-dose imaging protocol reconstructed at full and half doses with weighted filtered back projection (wFBP) and an improved sinogram-affirmed iterative reconstruction algorithm (SAFIRE*)....

Evaluation of the nontraumatic acute abdomen with multidetector CT has long been accepted and validated as the reference standard in the acute setting. Dual-energy CT has emerged as a promising tool, with multiple clinical applications in abdominal imaging already demonstrated. With its ability to allow characterization of materials on the basis of...

Purpose This retrospective study reports the frequency and severity of coronary artery motion on dual-source high-pitch (DSHP), conventional pitch single-source (SS), and dual-source dual-energy (DE) CT pulmonary angiography (CTPA) studies. Methods Two hundred eighty-eight consecutive patients underwent CTPA scans for suspected pulmonary embolism...

Magnetic resonance imaging (MRI) is the mainstay method for the radiological imaging of the small bowel in patients with inflammatory bowel disease without the use of ionizing radiation. There are circumstances where imaging using ionizing radiation is required, particularly in the acute setting. This usually takes the form of computed tomography (...

Purpose Emergency Departments (ED) are becoming busier, with a resultant increase in the number of imaging referrals. The purpose of this study was to assess the diagnostic accuracy of an abbreviated two sequence magnetic resonance (MR) protocol for evaluating ED patients with right lower quadrant pain and suspected acute appendicitis, with a view...

Purpose: Location, size, and local inflammatory findings in primary epiploic appendagitis (EA) have not been reported outside of small studies. The association between EA and increased adiposity is controversial. The goals of this project are to compare demographics and imaging-based measurements of adiposity between patients with EA and patients...

Objective: Sensitivity of CT of the abdomen for detection of acute bowel ischemia (ABI) can be as low as 60%. In this study, we assessed the diagnostic performance of iodine-map and monoenergetic (40-keV) images in patients with suspected ABI. Materials and methods: This retrospective study included 60 consecutive patients with suspected ABI who...

Objective: The objective of this study was to determine whether body fat percentage, measured using a portable handheld bioelectric impedance analysis (BIA) device, and body mass index (BMI, weight in kilograms divided by the square of height in meters) can estimate the amount of intraabdominal and intrapelvic fat and thereby predict the need for...

Background: Emergency general surgery conditions are often thought of as being too acute for the development of standardized approaches to quality improvement. However, process mapping, a concept that has been applied extensively in manufacturing quality improvement, is now being used in health care. The objective of this study was to create proce...

This study aims to identify the 50 most highly cited articles on dual energy computed tomography (DECT) in abdominal radiology Thomson Reuters Web of Science All Databases was queried without year or language restriction. Only original research articles with a primary focus on abdominal radiology using DECT were selected. Review articles, meta-anal...

Background: Emergency general surgery conditions are often thought of as being too acute for the development of standardized approaches to quality improvement. However, process mapping, a concept that has been applied extensively in manufacturing quality improvement, is now being used in health care. The objective of this study was to create proce...

PURPOSE Several papers have been published in recent years on the potential of Dual Energy CT (DECT) applications and how they may add clinical value to routine CT studies. Our study assessed the utilization rates of DECT in the emergency radiology department of a tertiary care hospital and level I trauma center and the clinical value added by dual...

Background: Surveillance after left atrial appendage (LAA) closure is important to assess for device success and complications. There is limited data on the role of cardiac computerized tomography angiography (CCTA) for LAA device monitoring. Methods: We retrospectively analyzed consecutive patients with non-valvular atrial fibrillation who underwe...

Objectives: We designed a prospective study to investigate the in-vivo relationship between abdominal body composition and radiation exposure to determine the strongest body composition predictor of dose length product (DLP) at CT. Methods: Following institutional review board approval, quantitative analysis was performed prospectively on 239 co...

The chapter will present recent evidence and controversies in diagnosis of acute abdominal pain due to pancreatitis and diverticulitis. Multidetector computed tomography (MDCT) has established indications and time frames for staging severity of pancreatitis in the acute phase. Currently, the role of MRI in diagnosis of acute pancreatitis had been i...

In an early online edition, the article title should have read as follows: Detection of Bone Marrow Edema in Nondisplaced Hip Fractures: Utility of a Virtual Noncalcium Dual-Energy CT Application. This has been corrected online and in print.

Purpose To quantify the sensitivity and specificity of dual-energy computed tomographic (CT) virtual noncalcium images in the detection of nondisplaced hip fractures and to assess whether obtaining these images as a complement to bone reconstructions alters sensitivity, specificity, or diagnostic confidence. Materials and Methods The clinical resea...

Objective Clearance of cervical spine injury including ligamentous injury is of paramount importance as results of missed injury may have serious consequences. In obtunded patients, cervical spine clearance is challenging. This study sought to determine whether a negative 64-slice CT scan alone is sufficient to clear cervical spine injury. Patient...

Introduction: The authors propose that tablet computers could benefit patients with acute stroke in the remote care setting, where time to and accuracy of CT interpretation greatly influences patient outcome. Methods: One hundred and fifty consecutive patients who presented to the Emergency Department of a tertiary referral neurosciences centre...

PURPOSE The role of the non-enhanced CT in the setting of acute stroke has always been that of a quick rule-out tool to exclude haemorrhage, with low accuracy in detecting acute infarcts and reported accuracy of 61%.DECT with material decomposition (MD) has shown promise in post post intra-arterial revascularization. We present a novel material dec...

PURPOSE Gallstone disease affects 10-15% of the population, and is a frequent cause of presentation to the ER for abdominal pain. Unfortunately, up to 80% of gallstones are radiolucent, making their diagnosis on x-ray or CT very difficult, and requiring an ultrasound or MRI for diagnosis. In this study, we hypothesized that radiolucent calculi not...

PURPOSE To evaluate the role of iodine quantification in differentiating colonic diverticulitis from colonic adenocarcinoma. METHOD AND MATERIALS Institutional review board approval was obtained, with no informed consent required, for this retrospective analysis. 146 consecutive patients with acute diverticulitis were scanned using a standard prot...

PURPOSE To evaluate the role of virtual monochromatic imaging (VMI) in the detection of peritoneal metastatic disease in contrast-enhanced computed tomography (CT) of the abdomen and pelvis and to compare this technique to conventional polychromatic imaging (PCI). METHOD AND MATERIALS Institutional review board approval was obtained, with no inform...

Introduction: We assess the ability of low-dose hybrid iterative reconstruction (IR) and 'pure' model-based IR (MBIR) images to maintain accurate Hounsfield unit (HU)-determined tissue characterization. Methods: Standard-protocol (SP) and low-dose modified-protocol (MP) CTs were contemporaneously acquired in 34 Crohn's disease patients referred...

Purpose of review This review article aims to give radiologists the most up to date evidence regarding the use of dual energy CT (DECT) in the assessment of patients with acute abdominal symptoms. Recent findings There is a growing body of evidence that DECT has an important clinical role in assessment of acute abdominal pathologies such as mesent...

Bibliometric analysis is the application of statistical methods to analyze quantitative data about scientific publications. It can evaluate research performance, author productivity, and manuscript impact. To the best of our knowledge, no bibliometric analysis has focused on cardiac computed tomography (CT). The purpose of this paper was to compile...

Methods: Twenty patients were included. Radiation dose was divided into a low-dose acquisition reconstructed with pure IR and a conventional dose acquisition reconstructed with 40% hybrid IR. Dose, image noise, contrast resolution, spatial resolution, and carotid artery stenosis were measured. Results: Mean effective dose was significantly lower...

Purpose: In patients with small bowel obstruction (SBO), it is challenging to detect early ischemia. The purpose of this study is to evaluate the quantitative and qualitative benefits of virtual monoenergetic image (VMI) reconstruction in the assessment of small bowel mural enhancement on dual source dual energy computed tomography (CT) scans of t...

In the setting of mass casualty incidents (MCI), hospitals need to divert from normal routine to delivering the best possible care to the largest number of victims. This should be accomplished by activating an established hospital Disaster Management Plan (DMP) known to all staff through prior training drills. Over the recent decades, imaging has i...

Methods: Thirty-four consecutive patients with CD were referred with suspected extramural complications. Two contemporaneous CT datasets were acquired in all patients: standard protocol (SP) and MP. The MP and SP protocols were designed to impart radiation exposures of 10% to 20% and 80% to 90% of routine abdominopelvic CT, respectively. The MP im...

Background: Left atrial appendage (LAA) closure requires accurate preprocedural measurements, and trans-esophageal echocardiography (TEE), cardiac computed tomography angiography (CCTA) and fluoroscopy can be utilized. However, correlations between these measurements remain inadequately assessed. Methods: Patients who underwent LAA closure at Va...

Objective: Dual-energy CT (DECT) is an innovative imaging modality that allows superior detection of pulmonary embolism, enhanced detection of urate in gout, and improved assessment of metal prostheses when compared with conventional CT. Conclusion: The primary aim of this review is to describe these DECT protocols and compare each to its respec...

The purpose of this study was to compare diaphragmatic motion on dual-source high-pitch (DS-HP) and conventional single-source (SS) CT scans in trauma patients. Seventy-five consecutive trauma patients who presented to a level one trauma center over a 6-month period were scanned with a standardized whole body trauma CT protocol including both DS-HP...

PURPOSE Acute intestinal ischemia and infarction are devastating abdominal emergencies, with mortality rates up to 93%. Clinical presentation is varied, with significant overlap with other acute abdominal disease. CT sensitivity for detection of acute bowel ischemia is poor, with reported values ranging from 60-80%. CT detection of bowel ischemia i...

Objective: The purpose of this study was to analyze the performance of pure model-based iterative reconstruction (MBIR) in low-dose CT enterography. Subjects and methods: Forty-four patients with Crohn disease referred for CT enterography were included. Low-dose modified-protocol and conventional-protocol CT datasets were contemporaneously acqui...

Background Despite limitations of routine methods, Clinical Practice Guidelines support the assessment of bone mineral density (BMD) and vascular calcification in renal transplant recipients. Changes in fat mass also occur post-transplantation, although they are traditionally difficult to measure accurately. We report the feasibility, convenience a...

Atrial fibrillation is prevalent and percutaneous left atrial appendage (LAA) closure is increasingly performed worldwide. This procedure is technically challenging and the success and procedural complexities depend on anatomy of the LAA and surrounding structures. These are readily depicted on cardiac computed tomography angiography (CCTA), which...

Dual energy computed tomography (DECT) is a revolutionary imaging modality, which has shown great promise for new and improved diagnostic avenues—particularly in the realm of musculoskeletal imaging. The primary aim of this review will be to discuss these recent advances, while also providing insight regarding the recognition of artifacts inherent...

The high morbidity and mortality associated with cervical spine injuries makes identification and classification essential. It is important to have a systematic approach to evaluation, especially in the trauma setting with other distracting injuries. Understanding the anatomy and biomechanics enables rapid and accurate interpretation of images. In...

Intestinal ischemia is a serious condition that continues to be associated with mortalities in excess of 70%. Intestinal obstruction and gastrointestinal tract sepsis are common conditions, accounting for a large proportion of patients admitted to emergency departments with acute abdominal symptoms. This article discusses the imaging methods and ke...

Aims: Left atrial appendage (LAA) device imaging after endovascular closure is important to assess for device thrombus, residual leak, positioning, surrounding structures, and pericardial effusion. Cardiac CT angiography (CCTA) is well suited to assess these non-invasively. Methods and results: We report our consecutive series of non-valvular at...

This chapter reviews radiation dose units (Air KERMA, Absorbed Dose, Equivalent Dose and Effective Dose), followed by a review of CT specific dose metrics (CTDI, DLP, and SSDE). Use of radiation units and dose metrics in monitoring CT dose is discussed, with emphasis on uncertainty in measurement, dose metric limitations and practical application....

Objectives: Risks associated with high cumulative effective dose (CED) from radiation are greater when imaging is performed on younger patients. Testicular cancer affects young patients and has a good prognosis. Regular imaging is standard for follow-up. This study quantifies CED from diagnostic imaging in these patients. Methods: Radiological i...

Purpose: The objective of this study is to establish the effect of third-generation integrated circuit (IC) CT detector on objective image quality in full- and half-dose non-contrast CT of the urinary tract. Methods: 51 consecutive patients with acute renal colic underwent non-contrast CT of the urinary tract using a 128-slice dual-source CT bef...

Purpose: To prospectively compare detection and reader confidence of pancreatic lesions using a standard multi-detector computed tomography (MDCT) imaging protocol to a dual-energy computed tomography (DECT) imaging protocol with additional virtual non-contrast series. Methods: 60 subjects imaged for suspected or known pancreatic lesions were in...

Purpose Pure iterative reconstruction (Pure IR) has been proposed as a solution to improve diagnostic quality of low dose CT images. We assess the performance of model based iterative reconstruction (MBIR) in improving conventional dose CT enterography (CTE) images. Methods 43 Crohn’s patients (27 female) (38.5 ± 12.98 years) referred for CTE we...

Increased use of CT Pulmonary angiography in suspected pulmonary embolism (PE) has driven research to minimize radiation dose while maintaining image quality and diagnostic accuracy. Following institutional review board approval, we performed a retrospective comparison study in patients with suspected PE. Patients were scanned using an ultra high p...

The purpose of this study is to describe our initial clinical experience with dual-energy computed tomography (DECT) virtual non-calcium (VNC) images for the detection of bone marrow (BM) edema in patients with suspected hip fracture following trauma. Twenty-five patients presented to the emergency department at a level 1 trauma center between Janu...

Computed tomography (CT) is often used to assess the presence of occult fractures when plain radiographs are equivocal in the acute traumatic setting. While providing increased spatial resolution, conventional computed tomography is limited in the assessment of bone marrow edema, a finding that is readily detectable on magnetic resonance imaging (M...

An integral part of realizing the enormous potential of imaging in patient care is close communication between radiologists and referring physicians. One key element of this process is the communication of unexpected significant findings. The authors examined the performance of a PACS-based alert system in the appropriate communication of reports c...

Computed tomography has become increasingly popular in the assessment of limbs in the acute trauma setting. Bony anatomic detail is excellent; however, soft tissue detail is typically limited, especially when compared with ultrasound and magnetic resonance imaging. The advent of dual-energy computed tomography has allowed additional information to...

Imaging of patients with large metal implants remains one of the most difficult endeavours for radiologists. This article reviews the theory of dual-energy CT (DECT) and its ability to reduce metal artefact, thus enhancing the diagnostic value of musculoskeletal imaging. The strengths, weaknesses, and alternative applications of DECT, as well as ar...

Radiologic investigations continue to play a pivotal role in the diagnosis of pathologic conditions of the small intestine despite enhancement of capsule endoscopy and double-balloon endoscopy. Imaging techniques continue to evolve and new techniques in MRI in particular, are being developed. Continued advances in computed tomography (CT) and MRI t...

Purpose An integral part of realizing the enormous potential of imaging in patient care is close communication between radiologists and referring physicians. One key element of this process is the communication of unexpected significant findings. The authors examined the performance of a PACS-based alert system in the appropriate communication of r...

Until recently, computed tomographic (CT) examinationsacquired at a radiation exposure equivalent to correspondingplain radiographs would be of grossly substandard imagequality, almost certainly resulting in a failure to adequatelyvisualize many anatomic structures. Over the past decade,successive technical breakthroughs have facilitateddiagnostic-...

There is increasing awareness of high cumulative ionizing radiation exposure in patients with Crohn's disease (CD). We outline the principle causes for concern and the subgroups of Crohn's patients at risk of greatest cumulative dose. We present a practical approach to radiation dose reduction in Crohn's patients with a focus on evolving CT Technol...