Radiology Commons^™

Labrad : Vol 40, Issue 1 - April 2014, Aga Khan University Hospital, Karachi

LABRAD - Departments of Pathology & Laboratory Medicine and Radiology Archives

• Provocative Testing for Growth Hormone Disorders
• Serum Procalcitonin for Early Sepsis Diagnosis
• Monoclonal Gammopathy of Undetermined Significance (MGUS)
• Understanding Six Sigma Methodology
• Blood Collection for Culture
• Molecular Analysis of Alpha Thalassaemia by Multiple Ligation Probe Assay
• Prognostification of Acute Myeloid Leukemia with FLT 3 Mutation
• Interferon Gamma Release Assay (IGRA) for Detection of Mycobacterium Tuberculosis Infection in the Host
• Meeting Report: The 37th Annual Conference of the Pakistan Association of Pathologists

Correlations Of Skin Fold Thickness And Validation Of Prediction Equations Using Dexa As The Gold Standard For Estimation Of Body Fat Composition In Pakistani Children., Zainab Hussain, Tazeen H. Jafar, Maseeh Uz Zaman, Riffat Parveen Hussain

Department of Radiology

OBJECTIVE:

To determine the correlation between dual energy X-ray absorptiometry (DEXA) and skin fold thickness (SKF) equations for estimation of body fat (BF) composition in secondary school children and validation of prediction equations by Slaughter, Goran and Dezenberg.

DESIGN:

Cross sectional analytical study.

SETTING:

Joint Commission for International Accredited (JCIA) tertiary care hospital of Karachi, Pakistan from January 2010 to May 2010.

PARTICIPANTS:

The study was approved by the Hospital's ethical review committee. Written and verbal consents were obtained from principals of two schools and parents of 99 children (mean age of 14±1.89 years; min-max 9-19 years; 54 men and …

Tumor Radiation Therapy Creates Therapeutic Vaccine Responses To The Colorectal Cancer Antigen Gucy2c., Matthew Witek, Erik S Blomain, Michael Sullivan Magee, Bo Xiang, Scott A Waldman, Adam E. Snook

Department of Pharmacology and Experimental Therapeutics Faculty Papers

PURPOSE: Radiation therapy (RT) is thought to produce clinical responses in cancer patients, not only through direct toxicity to cancer cells and supporting tumor stroma cells, but also through activation of immunologic effectors. More recently, RT has potentiated the local and systemic effects of cancer immunotherapy (IT). However, combination regimens that maximize immunologic and clinical efficacy remain undefined.

METHODS AND MATERIALS: We evaluated the impact of local RT on adenoviral-mediated vaccination against the colorectal cancer antigen GUCY2C (Ad5-GUCY2C) in a murine subcutaneous tumor model using mouse CT26 colon cancer cells (CT26-GUCY2C). Immune responses were assessed by ELISpot, and clinical responses …

3d Visualization Architecture For Building Applications Leveraging An Existing Validated Toolkit, David A. Polyak

Master's Theses (2009 -)

The diagnostic radiology space and healthcare in general is a slow adopter of new software technologies and patterns. Despite the widespread embrace of mobile technology in recent years, altering the manner in which societies in developed countries live and communicate, diagnostic radiology has not unanimously adopted mobile technology for remote diagnostic review. Desktop applications in the diagnostic radiology space commonly leverage a validated toolkit. Such toolkits not only simplify desktop application development but minimize the scope of application validation. For these reasons, such a toolkit is an important piece of a company’s software portfolio. This thesis investigated an approach for …

Introducing And Evaluating 3d Digital Breast Tomosynthesis, Marie Hrinkonich, Susan Steigerwalt

Department of Radiology & Diagnostic Medical Imaging

No abstract provided.

5-Fu Induced Acute Toxic Leukoencephalopathy: Early Recognition And Reversibility On Dwi-Mri, Shayan Sirat Maheen Anwar,, Fatima Mubarak, Zafar Sajjad, Muhammad Azeemuddin

Department of Radiology

Acute toxic leukoencephalopathy (ATL) is a rare adverse effect of 5-Fluorouracil (5-FU) chemotherapeutic agent. It is imperative for the radiologist to confidently identify the white matter changes caused by this agent in case of toxicity. This will help in early detection and appropriate management of patient, as the condition is reversible both clinically and on imaging. We report a case of a 29 years old gentleman, known case of carcinoma of esophagus who suffered from acute toxic leukoencephalopathy secondary to leukotoxic therapeutic agent 5-FU, and illustrate the reversible imaging findings of this condition on withdrawal of the inciting agent.

A Randomized Trial Of Bevacizumab For Newly Diagnosed Glioblastoma., Mark R Gilbert, James J Dignam, Terri S Armstrong, Jeffrey S Wefel, Deborah T Blumenthal, Michael A Vogelbaum, Howard Colman, Arnab Chakravarti, Stephanie Pugh, Minhee Won, Robert Jeraj, Paul D Brown, Kurt A Jaeckle, David Schiff, Volker W Stieber, David G Brachman, Maria Werner-Wasik, Ivo W Tremont-Lukats, Erik P Sulman, Kenneth D Aldape, Walter J Curran, Minesh P Mehta

Department of Radiation Oncology Faculty Papers

BACKGROUND: Concurrent treatment with temozolomide and radiotherapy followed by maintenance temozolomide is the standard of care for patients with newly diagnosed glioblastoma. Bevacizumab, a humanized monoclonal antibody against vascular endothelial growth factor A, is currently approved for recurrent glioblastoma. Whether the addition of bevacizumab would improve survival among patients with newly diagnosed glioblastoma is not known.

METHODS: In this randomized, double-blind, placebo-controlled trial, we treated adults who had centrally confirmed glioblastoma with radiotherapy (60 Gy) and daily temozolomide. Treatment with bevacizumab or placebo began during week 4 of radiotherapy and was continued for up to 12 cycles of maintenance chemotherapy. …

Epicatechin Stimulates Mitochondrial Activity And Selectively Sensitizes Cancer Cells To Radiation, Hosam A. Elbaz, Icksoo Lee, Deborah A. Antwih, Jenney Liu, Maik Hüttemann, Steven P. Zielske

Center for Molecular Medicine and Genetics

Radiotherapy is the treatment of choice for solid tumors including pancreatic cancer, but the effectiveness of treatment is limited by radiation resistance. Resistance to chemotherapy or radiotherapy is associated with reduced mitochondrial respiration and drugs that stimulate mitochondrial respiration may decrease radiation resistance. The objectives of this study were to evaluate the potential of (-)-epicatechin to stimulate mitochondrial respiration in cancer cells and to selectively sensitize cancer cells to radiation. We investigated the natural compound (-)-epicatechin for effects on mitochondrial respiration and radiation resistance of pancreatic and glioblastoma cancer cells using a Clark type oxygen electrode, clonogenic survival assays, and …

Utilizing Fast Spin Echo Mri To Reduce Image Artifacts And Improve Implant/Tissue Interface Detection In Refractory Parkinson’S Patients With Deep Brain Stimulators, Subhendra N. Sarkar, Pooja R. Sarkar, Efstathios Papavassiliou, Rafael Rojas

Publications and Research

Introduction. In medically refractory Parkinson’s disease (PD) deep-brain stimulation (DBS) is an effective therapeutic tool. Postimplantation MRI is important in assessing tissue damage and DBS lead placement accuracy. We wanted to identify which MRI sequence can detectDBS leads with smallest artifactual signal void, allowing better tissue/electrode edge conspicuity.

Methods. Using an IRB approved protocol 8 advanced PDpatientswere imagedwithinMRconditional safety guidelines at lowRF power (SAR ≤ 0.1 W/kg) in coronal plane at 1.5T by various sequences.The image slices were subjectively evaluated for diagnostic quality and the lead contact diameters were compared to identify a sequence least affected by metallic leads.

Results …

Two Cases Of Spinal, Extraosseous, Intradural Ewing's Sarcoma/Peripheral Neuroectodermal Tumor: Radiologic, Pathologic, And Molecular Analysis., Stacey K. Mardekian, Ashish Gandhe, Md, Markku Miettinen, Svetlana Pack, Mark T. Curtis Md, Phd, Ziedulla Abdullaev

Department of Radiology Faculty Papers

Extraosseous Ewing's sarcoma/peripheral neuroectodermal tumors (ES/PNETs) are rare neoplasms that account for approximately 10%-15% of soft tissue sarcomas in children and 5% of soft tissue sarcomas in adults. Primary spinal, extraosseous, intradural ES/PNETs are even less common. The diagnosis of ES/PNET is extremely challenging, because the tumor can have a nonspecific radiologic appearance, and the histologic features are shared by many other "small round cell tumors." Thus, ES/PNET should be included in the radiologic and pathologic differential diagnosis, even in older patients and in unusual tumor sites. We report two cases of spinal, extraosseous, intradural ES/PNETs in adults who presented …

Regulation Of The Proapoptotic Functions Of Prostate Apoptosis Response-4 (Par-4) By Casein Kinase 2 In Prostate Cancer Cells, A De Thonel, A Hazoumé, V Kochin, K Isoniemi, G Jego, E Fourmaux, A Hammann, H Mjahed, O Filhol, O Micheau, P Rocchi, V Mezger, J E Eriksson, Vivek M. Rangnekar, C Garrido

Radiation Medicine Faculty Publications

The proapoptotic protein, prostate apoptosis response-4 (Par-4), acts as a tumor suppressor in prostate cancer cells. The serine/threonine kinase casein kinase 2 (CK2) has a well-reported role in prostate cancer resistance to apoptotic agents or anticancer drugs. However, the mechanistic understanding on how CK2 supports survival is far from complete. In this work, we demonstrate both in rat and humans that (i) Par-4 is a new substrate of the survival kinase CK2 and (ii) phosphorylation by CK2 impairs Par-4 proapoptotic functions. We also unravel different levels of CK2-dependent regulation of Par-4 between species. In rats, the phosphorylation by CK2 at …

Paracrine Apoptotic Effect Of P53 Mediated By Tumor Suppressor Par-4, Ravshan Burikhanov, Tripti Shrestha-Bhattarai, Nikhil Hebbar, Shirley Qiu, Yanming Zhao, Gerard P. Zambetti, Vivek M. Rangnekar

Radiation Medicine Faculty Publications

The guardian of the genome, p53, is often mutated in cancer and may contribute to therapeutic resistance. Given that p53 is intact and functional in normal tissues, we harnessed its potential to inhibit the growth of p53-deficient cancer cells. Specific activation of p53 in normal fibroblasts selectively induced apoptosis in p53-deficient cancer cells. This paracrine effect was mediated by p53-dependent secretion of the tumor suppressor Par-4. Accordingly, the activation of p53 in normal mice, but not p53⁻/⁻ or Par-4⁻/⁻ mice, caused systemic elevation of Par-4, which induced apoptosis of p53-deficient tumor cells. Mechanistically, p53 …

Estimation Of Daily Interfractional Larynx Residual Setup Error After Isocentric Alignment For Head And Neck Radiotherapy: Quality Assurance Implications For Target Volume And Organs-At-Risk Margination Using Daily Ct On- Rails Imaging., Charles A Baron, Musaddiq J Awan, Abdallah S R Mohamed, Imad Akel, David I Rosenthal, G Brandon Gunn, Adam S Garden, Brandon A Dyer, Laurence Court, Parag R Sevak, Esengul Kocak-Uzel, Clifton D Fuller

Department of Medicine Faculty Papers

Larynx may alternatively serve as a target or organs at risk (OAR) in head and neck cancer (HNC) image-guided radiotherapy (IGRT). The objective of this study was to estimate IGRT parameters required for larynx positional error independent of isocentric alignment and suggest population-based compensatory margins. Ten HNC patients receiving radiotherapy (RT) with daily CT on-rails imaging were assessed. Seven landmark points were placed on each daily scan. Taking the most superior-anterior point of the C5 vertebra as a reference isocenter for each scan, residual displacement vectors to the other six points were calculated postisocentric alignment. Subsequently, using the first scan …

Skin Lesion Extraction And Its Application, Yanliang Gu

Dissertations, Master's Theses and Master's Reports - Open

In this thesis, I study skin lesion detection and its applications to skin cancer diagnosis. A skin lesion detection algorithm is proposed. The proposed algorithm is based color information and threshold. For the proposed algorithm, several color spaces are studied and the detection results are compared. Experimental results show that YUV color space can achieve the best performance. Besides, I develop a distance histogram based threshold selection method and the method is proven to be better than other adaptive threshold selection methods for color detection. Besides the detection algorithms, I also investigate GPU speed-up techniques for skin lesion extraction and …

Improving Low-Dose Blood-Brain Barrier Permeability Quantification Using Sparse High-Dose Induced Prior For Patlak Model, R. Fang, K. Karlsson, T. Chen, P. C. Sanelli

Journal Articles

Blood-brain barrier permeability (BBBP) measurements extracted from the perfusion computed tomography (PCT) using the Patlak model can be a valuable indicator to predict hemorrhagic transformation in patients with acute stroke. Unfortunately, the standard Patlak model based PCT requires excessive radiation exposure, which raised attention on radiation safety. Minimizing radiation dose is of high value in clinical practice but can degrade the image quality due to the introduced severe noise. The purpose of this work is to construct high quality BBBP maps from low-dose PCT data by using the brain structural similarity between different individuals and the relations between the high- …

White Matter Involvement In Chronic Musculoskeletal Pain, G. Lieberman, M. Shpaner, R. Watts, T. Andrews, C. G. Filippi, M. Davis, M. R. Naylor

Journal Articles

There is emerging evidence that chronic musculoskeletal pain is associated with anatomic and functional abnormalities in gray matter. However, little research has investigated the relationship between chronic musculoskeletal pain and white matter. In this study, we used whole-brain tract-based spatial statistics and region-of-interest analyses of diffusion tensor imaging data to demonstrate that patients with chronic musculoskeletal pain exhibit several abnormal metrics of white matter integrity compared with healthy controls. Chronic musculoskeletal pain was associated with lower fractional anisotropy in the splenium of the corpus callosum and the left cingulum adjacent to the hippocampus. Patients also had higher radial diffusivity in …

Does The Location Of The Arterial Input Function Affect Quantitative Ctp In Patients With Vasospasm?, B. J. Shin, N. Anumula, S. Hurtado-Rua, P. Masi, R. Campbell, R. Spandorfer, A. Ferrone, T. Caruso, A. Gupta, P. C. Sanelli, +2 Additional Authors

Journal Articles

BACKGROUND AND PURPOSE: In recent years, there has been increasing use of CTP imaging in patients with aneurysmal SAH to evaluate for vasospasm. Given the critical role of the arterial input function for generation of accurate CTP data, several studies have evaluated the effect of varying the arterial input function location in patients with acute stroke. Our aim was to determine the effect on quantitative CTP data when the arterial input function location is distal to significant vasospasm in patients with aneurysmal SAH. MATERIALS AND METHODS: A retrospective study was conducted of patients with aneurysmal SAH admitted from 2005 to …

Imaging And Treatment Of Patients With Acute Stroke: An Evidence-Based Review, P. C. Sanelli, J. B. Sykes, A. L. Ford, J. M. Lee, K. D. Vo, D. K. Hallam

Journal Articles

Evidence-based medicine has emerged as a valuable tool to guide clinical decision-making, by summarizing the best possible evidence for both diagnostic and treatment strategies. Imaging plays a critical role in the evaluation and treatment of patients with acute ischemic stroke, especially those who are being considered for thrombolytic or endovascular therapy. Time from stroke-symptom onset to treatment is a strong predictor of long-term functional outcome after stroke. Therefore, imaging and treatment decisions must occur rapidly in this setting, while minimizing unnecessary delays in treatment. The aim of this review was to summarize the best available evidence for the diagnostic and …

Delayed Cerebral Ischemia In Aneurysmal Subarachnoid Hemorrhage: Proposal Of An Evidence-Based Combined Clinical And Imaging Reference Standard, P. C. Sanelli, S. Kishore, A. Gupta, H. Mangat, A. Rosengart, H. Kamel, A. Segal

Journal Articles

Aneurysmal subarachnoid hemorrhage is associated with high morbidity and mortality, with delayed neurologic deficits from delayed cerebral ischemia contributing to a large portion of the adverse outcomes in this patient population. There is currently no consensus reference standard for establishing the diagnosis of delayed cerebral ischemia either in the research or clinical settings, ultimately limiting strategies for preventing delayed infarction and permanent neurologic deficits. There are currently both clinical and imaging-based criteria for the diagnosis of delayed neurologic deficits and vasospasm, respectively, however, neither clinical nor angiographic assessment alone has been shown to identify patients who develop adverse outcomes from …

Pivotal Trial To Evaluate The Safety And Efficacy Of The Orbital Atherectomy System In Treating De Novo, Severely Calcified Coronary Lesions (Orbit Ii), J. W. Chambers, R. L. Feldman, S. I. Himmelstein, R. Bhatheja, A. E. Villa, K. C. Patel, J. A. Puma, P. Makam, B. D. Bertolet, G. Y. Nseir, +10 Additional Authors

Journal Articles

Objectives The ORBIT II (Evaluate the Safety and Efficacy of OAS in Treating Severely Calcified Coronary Lesions) trial evaluated the safety and efficacy of the coronary Orbital Atherectomy System (OAS) to prepare de novo, severely calcified coronary lesions for stent placement. Background Despite advances in interventional techniques, treatment of calcified coronary lesions remains a challenge. Stent placement in these lesions may result in stent underexpansion, malapposition, and procedural complications. Methods ORBIT II is a prospective, multicenter, nonblinded clinical trial that enrolled 443 consecutive patients with severely calcified coronary lesions at 49 U.S. sites from May 25, 2010, to November 26, …

Combined Pulmonary Venous Thromboembolism And Renal Artery Thrombosis In A Patient With Non-Small Cell Lung Cancer, G. Mavani, S. Machnicki, R. Lavie

Journal Articles

No abstract provided.

Internal Maxillary Artery-Middle Cerebral Artery Bypass: Infratemporal Approach For Subcranial-Intracranial (Sc-Ic) Bypass, E. Nossek, P. Costantino, M. Eisenberg, A. R. Dehdashti, A. Setton, D. J. Chalif, R. A. Ortiz, D. J. Langer

Journal Articles

BACKGROUND:Internal maxillary artery (IMax)-middle cerebral artery (MCA) bypass has been recently described as an alternative to cervical extracranial-intracranial bypass. This technique uses a keyhole craniectomy in the temporal fossa that requires a technically challenging end-to-side anastomosis.OBJECTIVE:To describe a lateral subtemporal craniectomy of the middle cranial fossa floor to facilitate wide exposure of the IMax to facilitate bypass.METHODS:Orbitozygomatic osteotomy is used followed by frontotemporal craniotomy and subsequently laterotemporal fossa craniectomy, reaching its medial border at a virtual line connecting the foramen rotundum and foramen ovale. The IMax was identified by using established anatomic landmarks, neuronavigation, and micro Doppler probe (Mizuho Inc. …

Mirror Image Artifact Mimicking Heterotopic Pregnancy On Transvaginal Ultrasound: Case Series, R. Malhotra, R. M. Bramante, M. Radomski, M. Nelson

Journal Articles

Vaginal bleeding in early pregnancy is a common emergency department complaint. Point-of-care ultrasound is a useful tool to evaluate for intrauterine ectopic pregnancy. Emergency physicians performing these studies need to be cognizant of artifacts produced by ultrasound technology, as they can lead to misdiagnosis. We present two cases where mirror-image artifacts initially led to a concern for heterotopic pregnancies but were excluded on further imaging.

Diagnosis Of Abnormal Biliary Copper Excretion By Positron Emission Tomography With Targeting Of (64)Copper-Asialofetuin Complex In Lec Rat Model Of Wilson's Disease, R. Bahde, S. Kapoor, K. K. Bhargava, C. J. Palestro, S. Gupta

Journal Articles

Identification by molecular imaging of key processes in handling of transition state metals, such as copper (Cu), will be of considerable clinical value. For instance, the ability to diagnose Wilson's disease with molecular imaging by identifying copper excretion in an ATP7B-dependent manner will be very significant. To develop highly effective diagnostic approaches, we hypothesized that targeting of radiocopper via the asialoglycoprotein receptor will be appropriate for positron emission tomography, and examined this approach in a rat model of Wilson's disease. After complexing (64)Cu to asialofetuin we studied handling of this complex compared with (64)Cu in healthy LEA rats and diseased …

Ct Perfusion For Detection Of Delayed Cerebral Ischemia In Aneurysmal Subarachnoid Hemorrhage: A Systematic Review And Meta-Analysis, D. I. A. Mir, A. Gupta, A. Dunning, L. Puchi, C. L. Robinson, H. A. B. Epstein, P. C. Sanelli

Journal Articles

BACKGROUND AND PURPOSE: Delayed cerebral ischemia is a significant cause of morbidity and mortality after aneurysmal SAH, leading to poor outcomes. The purpose of this study was to evaluate the usefulness of CTP in determining delayed cerebral ischemia in patients with aneurysmal SAH. MATERIALS AND METHODS: We conducted a systematic review evaluating studies that assessed CTP in patients with aneurysmal SAH for determining delayed cerebral ischemia. Studies using any of the following definitions of delayed cerebral ischemia were included in the systematic review: 1) new onset of clinical deterioration, 2) cerebral infarction identified on follow-up CT or MR imaging, and …

Nuclear Medicine And The Failed Joint Replacement: Past, Present, And Future, C. J. Palestro

Journal Articles

Soon after the introduction of the modern prosthetic joint, it was recognized that radionuclide imaging provides useful information about these devices. The bone scan was used extensively to identify causes of prosthetic joint failure. It became apparent, however, that although sensitive, regardless of how the images were analyzed or how it was performed, the test was not specific and could not distinguish among the causes of prosthetic failure. Advances in anatomic imaging, notably cross sectional modalities, have facilitated the diagnosis of many, if not most, causes of prosthetic failure, with the important exception of infection. This has led to a …

Traumatic Axillary Artery Pseudoaneurysm Treated With Intravascular Balloon Occlusion And Percutaneous Thrombin Injection, Maria Carratola, Priti Parikh, Kathryn M. Tchorz, Shannon Kauffman

Department of Surgery Faculty Publications

Axillary artery pseudoaneurysms are relatively rare, with few reported cases found in the literature. Furthermore, treatment with percutaneous thrombin injection has not yet been reported. We report the case of a 59-year-old man with a large (10 cm) post-traumatic pseudoaneurysm of the left axillary artery found five weeks after a motorcycle crash. The patient sustained multiple injuries, including fractures of the left scapula and clavicle. Edema was observed at the time of diagnosis. Arteriography with successful ultrasound-guided percutaneous thrombin injection was undertaken. The patient experienced no complications after the procedure.

Appropriate Use Of Ct Perfusion Following Aneurysmal Subarachnoid Hemorrhage: A Bayesian Analysis Approach, R. P. Killeen, A. Gupta, H. Delaney, C. E. Johnson, A. J. Tsiouris, M. E. Fink, H. S. Mangat, A. Z. Segal, A. I. Mushlin, P. C. Sanelli, +1 Additional Author

Journal Articles

These investigators evaluated the test characteristics of CTP in patients with SAH for detection of delayed cerebral ischemia. Ninety-seven patients were assessed with CTP for ischemia and with DSA for vasospasm. The authors concluded that positive CTP findings identified patients who should be carefully considered for induced hypertension, hypervolemia, and hemodilution and/or intra-arterial therapy while negative CTP findings are useful in guiding a no-treatment decision. BACKGROUND AND PURPOSE: In recent years CTP has been used as a complementary diagnostic tool in the evaluation of delayed cerebral ischemia and vasospasm. Our aim was to determine the test characteristics of CTP for …

Cost-Effectiveness Of Ct Angiography And Perfusion Imaging For Delayed Cerebral Ischemia And Vasospasm In Aneurysmal Subarachnoid Hemorrhage, P. C. Sanelli, A. Pandya, A. Z. Segal, A. Gupta, S. Hurtado-Rua, J. Ivanidze, K. Kesavabhotla, D. Mir, A. I. Mushlin, M. G. Hunink

Journal Articles

BACKGROUND AND PURPOSE: Delayed cerebral ischemia and vasospasm are significant complications following SAH leading to cerebral infarction, functional disability, and death. In recent years, CTA and CTP have been used to increase the detection of delayed cerebral ischemia and vasospasm. Our aim was to perform comparative-effectiveness and cost-effectiveness analyses evaluating CTA and CTP for delayed cerebral ischemia and vasospasm in aneurysmal SAH from a health care payer perspective. MATERIALS AND METHODS: We developed a decision model comparing CTA and CTP with transcranial Doppler sonography for detection of vasospasm and delayed cerebral ischemia in SAH. The clinical pathways were based on …

Potholes And Molehills: Bias In The Diagnostic Performance Of Diffusion-Tensor Imaging In Concussion, R. Watts, A. Thomas, C. G. Filippi, J. P. Nickerson, K. Freeman

Journal Articles

PURPOSE: To investigate the extent of bias in a clinical study involving "pothole analysis" of diffusion-tensor imaging (DTI) data used to quantify white matter lesion load in diseases with a heterogeneous spatial distribution of pathologic findings, such as mild traumatic brain injury (TBI), and create a mathematical model of the bias. MATERIALS AND METHODS: Use of the same reference population to define normal findings and make comparisons with a patient group introduces bias, which potentially inflates reported diagnostic performance. In this institutional review board-approved prospective observational cohort study, DTI data were obtained in 20 patients admitted to the emergency department …