Nicola H. Strickland

Abnormal myocardial insulin signalling in type 2 diabetes and left-ventricular dysfunction

AIMS Whole body and myocardial insulin resistance are features of non-insulin-dependent diabetes mellitus (NIDDM) and left-ventricular dysfunction (LVD). We determined whether abnormalities of insulin receptor substrate-1 (IRS1), IRS1-associated PI3K (IRS1-PI3K), and glucose transporter 4 (GLUT4) contribute to tissue-specific insulin resistance. METHODS AND RESULTS We collected skeletal muscle (n = 27) and myocardial biopsies (n = 24) from control patients (n = 7), patients with NIDDM (n = 9) and patients with LVD (n = 8), who were characterized by euglycaemic-hyperinsulinaemic clamp and positron emission tomography. Comparative studies were carried out in three mouse models. We demonstrate an unrecognized reduction of IRS1 in skeletal muscle of LVD patients and an unexpected increase in cardiac IRS1-PI3K activity in NIDDM and LVD patients. In NIDDM, there was a concomitant reduction in sarcolemmal GLUT4, whereas in patients with LVD sarcolemmal GLUT4 was increased. We confirm activation of IRS1-PI3K and reduction in sarcolemmal GLUT4 in the insulin resistant ob/ob mouse heart where we also demonstrate perturbation of GLUT4 docking and fusion. A direct relationship between PI3K and GLUT4 was demonstrated in mice expressing activated PI3K in the heart and increased GLUT4 at the sarcolemma was confirmed in a mouse model of LVD. CONCLUSION Our data show that the mechanisms of myocardial insulin resistance are different between NIDDM and LVD.

PACS (picture archiving and communication systems): filmless radiology

A picture archiving and communication system (PACS) is a computerised means of replacing the roles of conventional radiological film. This review describes the Hammersmith PACS, and discusses the advantages and disadvantages of PACS systems.

A comparison of conventional film, CR hard copy and PACS soft copy images of the chest: analyses of ROC curves and inter-observer agreement

STUDY OBJECTIVE The aim of this study was to determine whether the accuracy of diagnosis of a spectrum of chest pathology was affected by the imaging technique used, and to compare conventional film/screen, hard copy computed (phosphor plate) radiography (CR) and soft copy CR (PACS) images. MATERIALS AND METHODS For each of 44 patients who had a CT examination of the thorax, PA and lateral chest radiographs were produced using conventional film, hard copy CR and soft copy PACS images. Five radiologists independently scored all images for the presence of abnormalities. The data were analysed in two stages using the result of the CT scan as the reference standard diagnosis: firstly, to investigate differences in abnormality scores between image modalities and observers using ROC analysis; secondly, to investigate the agreement of the diagnoses with the reference standard by the analysis of kappa scores. RESULTS The ROC analyses and comparison of kappa scores showed no differences between image modalities (P=0.72, P=0.87), but highly significant differences between observers (P<0.001, P=0.003). CONCLUSION The detection of chest lesions did not vary between conventional film, CR hard copy and PACS soft copy images. For all three image types, there were statistically significant differences between observers.

Can PACS make a radiology department more competitive

One of the motives for putting in a picture archiving and communication system (PACS) is to improve efficiency and hence enhance the competitive strength of the radiology department. Many would argue that it is now negligent to consider installing an old fashioned conventional radiology department rather than a PACS. In considering the issue it is important to be clear about the nature of the competition facing radiologists. This varies depending on the country and upon whether the institution is public or private. PACS can potentially help to overcome this competition in two ways: by providing real-time radiology, and by enabling teleradiology. Success in these areas requires state-of-the-art implementations of PACS, particularly clinically relevant PACS software, and adequate staffing levels.

Fibrolamellar carcinoma: an unusual clinico-radiological presentation.

We report a case of fibrolamellar carcinoma presenting in a 26-year old female. The patient had gross ascites at presentation. Imaging studies (ultrasonography and computed tomography) strongly suggested extensive intraperitoneal drop metastases.

Design for the optimal arrangement of magnetic resonance images on PACS monitors

A default display protocol (DDP) has been designed for reading magnetic resonance (MR) images on PACS workstations. This MR DDP is very flexible allowing any MR series from the current or previous studies to be simultaneously viewed and juxtaposed for direct comparison. There is a choice of image display format, selected by the radiologist from an icon bar, comprising four linked image series stacks, two linked image series tile clusters and linked tile mode. The selection and resultant monitor display arrangement is made by dragging and dropping token images into the chosen display format icon. The radiologist selects the best reversibly locked together so they can be scrolled in synchrony.

Organization of intensive therapy unit images on PACS monitors

The purpose of this paper is to present the default display protocol (DDP) we have devised for the spatial and temporal organization on PACS monitors of chest images taken in the intensive therapy unit (ITU). The goal is that when a patient has ITU status, his/her images will appear by default automatically ordered and arranged in the configuration most clinically useful and appropriate to the ITU setting. This DDP takes into account features specific to the ITU patient, namely: (1) the comparison of multiple chest images from the same patient in accurate temporal sequence to assess subtle trends in disease course; (2) the ability to display any desired image at maximum resolution for diagnostic purposes, and then quickly revert to displaying the entire image sequence; (3) minimization of the time spent in rearranging images on the display monitor; and (4) adaptation of the DDP to suit 1, 2, or 4 monitor workstations.

Hairy cell leukemia presenting as a cranial mass

A 42-year-old gentleman presented with a one month history of occipital swelling, on a background of intermittent headaches over the previous 6 months. He was, otherwise, fit and well. He had suffered a head injury 2 years earlier but there was no other past medical history of note, and he took no regular medications. His family history revealed a sibling and an aunt to have had Hodgkin’s lymphoma. He was a nonsmoker and drank 21 units of alcohol per week. Examination confirmed a right-sided occipital swelling but was otherwise unremarkable. Imaging of the head was performed using both computed tomography (Image 1) and magnetic resonance imaging (Image 2). A solid lesion was seen to overlie the right occipital bone with permeative destruction of the underlying skull vault and intracranial extension into the extradural space. Biopsy of the lesion was performed under ultrasound guidance. Histology revealed monomorphic intermediate sized cells expressing CD20, CD79a, BCL2 and cyclin D1, suggestive of a B cell lymphoid neoplasm. A full blood count demonstrated bicytopenia (white blood cell count 1.7 3 10/L haemoglobin 14.5 g/dL, platelet count 74 3 10/L), with the unusual finding of monocytopenia (0.1 3 10/L). Bone marrow aspiration revealed a population of cells morphologically resembling hairy cell leukemia (Image 3). Flow cytometry confirmed this diagnosis, revealing a population of B cells with the classical immunophenotypic profile for hairy cell leukemia: CD20, CD22, CD11c, CD25, CD103, and CD123. Positron emission tomography-computed tomography of the chest, abdomen, and pelvis revealed disseminated disease, with splenomegaly, widespread lymphadenopathy Image 2. Coronal T2-weighted magnetic resonance imaging scan of the head, revealing intracranial extension of the lesion into the extradural space. Image 1. Axial computed tomography scan of the head, demonstrating a solid mass lesion with destruction of the underlying skull vault.

Matching images from digital modalities to exams scheduled via RIS or PACS

In many hospitals, radiological examinations are scheduled via a Radiology Information System (RIS) or Picture Archiving and Communication System (PACS) before the imaging is performed. Demographic and examination information is first entered into the PACS database; when the images are later acquired, they have to match up with the correct pre-scheduled exam. This problem is non-trivial because patients may be scheduled for several exams on the same modality on the same day, and older modalities are unable to identify unambiguously the type of examination being performed. The purpose of this work is to develop practical and reliable strategies to assist in matching up the correct exam. Three potential solutions are considered: (1) modifications to imaging hardware and/or software, which force a PACS- generated exam ID into the image headers at acquisition time and thus guarantee a perfect match; (2) profiling algorithms, which attempt to find a match based on information already contained within the image headers; and (3) interactive Modality Examination Terminals (METs), which query the PACS database and assist human operators in manually selecting an appropriate exam. Solution (1) was found to be impractical with our existing digital imaging equipment, therefore solutions (2) and (3) were implemented and evaluated. Configuration files read at start-up time permitted the same hardware to be operated in either profiling or true MET mode. For each digital imaging modality the most appropriate mode of operation was determined, maintaining as far as possible a consistent hardware and software user interface.