SHORT REPORT SHORT REPORT 24 SA JOURNAL OF RADIOLOGY • December 2006 SHORT REPORT 24 SA JOURNAL OF RADIOLOGY • December 2006 Magnetic resonance imaging (MRI) of the orbits occasionally demon- strates retinal detachment (RD); this may be as an incidental finding, as a separate entity related to orbital pathology with differing local causes, or as a part of other congenital systemic or metabolic diseases. One con- genital ocular disease which could be misdiagnosed as RD is persistent hyperplastic primary vitreous (PHPV), which itself can be associated with RD. MRI scanning features of retinal detachment and associated causes can assist in differentiating both entities effectively, allowing the radiologist to reach the proper conclusions with resultant benefits in subsequent management. Persistent hyperplastic primary vitreous (PHPV) This is a congenital ocular lesion due to incomplete regression of embryonic ocular blood supply. The primary vitreous is supplied by the embryonic hyaloid vasculature, including the hyaloid artery (a branch of the ophthalmic artery of the developing globe), and should normally have disappeared by the time of birth.1,2 PHPV is usually isolated and unilateral; bilateral lesions tend to be associated with systemic or syn- dromic conditions. The most common presenting signs and symptoms are leukocoria, poor vision and small eye. Anterior PHPV has the best prognosis for vision, but approxi- mately half of these patients also have an associated posterior PHPV. Abnormalities of the lens and anterior chamber are signs of a combined anterior and posterior variant of PHPV; the isolated forms are roughly equal in incidence.1 Repeated episodes of intravitreal haemorrhage in patients with PHPV can lead to retraction of the posterior hyaloid membrane and retina by intravitreal fibrovascular tissue. This can then cause detachment of the posterior hyaloid membrane and retina.3 Retinal detachment is common and may be associated with layering of blood or debris (subretinal hemorrhage) (Fig. 1).1, 2 MRI findings PHPV typically appears as a triangular, retrolental vascular soft tissue mass, often with a central tissue stalk of hyaloid remnant connected to the optic disc. The overall shape of PHPV has been likened to a martini glass. The globe is usually small, with the vitreous typically abnormally hyper- intense on both T1 and T2-weighted sequences. The signal intensity of layered haemorrhage in vitreous can vary with the age of blood (Fig. 1). Retinal detachment (RD) Separation of the inner sensory retina from the pigmented retinal epithelium is referred to as retinal detachment. The sensory retina is part of the central nervous system, so that if there is a tear, the sensory retina cannot heal.3 Patients typically will present with symptoms such as light flashes, floaters, peripheral visual field loss and blurred vision. RD should be considered in the differential diagnosis of any visual loss. Risk factors for RD include advancing age, previous cataract surgery, myopia, and trauma.4 Mostly, RD is the result of separation caused by a mass (neoplastic, such as melanoma), a fibroproliferative disease in the vitreous such as vitreo-retinopathy, often either due to prematurity or diabetes, or an inflammatory process (such as uveitis). RD may also result from retinal vascular leakage (lipoproteinaceous exudates), as seen in patients with Coats’ disease, a vascular anomaly of retina (telangiecta- sis), or due to congenital diseases such as PHPV.3 MRI findings of RD As the retina itself is beyond the limits of resolution of MRI scanning, it is only seen when outlined by the significant contrast differences between the signal intensities of subretinal effusions and of the vitreous cavity. The MRI appearance of RD varies depending on the amount of exudate and the organisation of subretinal changes. MRI can differentiate exu- dative RD (rich in protein; hyperintense on both T1 and T2-weighted sequences) from subretinal fluid formation as in a rhegmatogenous RD (transudate fluid; hyperintense on T2 and hypointense on T1-weighted imaging sequences). In the case of haemorrhagic RD, the MRI signal Persistent hyperplastic primary vitreous versus retinal detachment H Lameen, MB ChB S Andronikou, MB BCh, FCRad (D), FRCR (Lond), PhD C Ackermann, MB ChB, MMed Rad (D), MRCS (UK) G Cilliers, MB ChB, MMed Rad (D) O C Schulze, MB ChB A Erlank, MB ChB J J Parsons, MB ChB P J Greyling, MB ChB, BSc (Hons) Department of Radiology, Tygerberg Hospital and Stellenbosch University Fig. 1. Axial T2-weighted image demonstrates bilateral anterior and poste- rior PHPV. Left eye: (Posterior PHPV) most of the globe content gives a very high signal that could be due to intraocular haemorrhage accompanying retinal detachment. Note canal of Cloquet (hyaloid canal) connecting the optic disc to the lens. Right eye: the displaced retina appears as a thin black line (arrow). The low signal represents subretinal haematoma that extends to the anterior chamber. pg24-25.indd 24 12/11/06 10:59:19 AM SHORT REPORTSHORT REPORT 25 SA JOURNAL OF RADIOLOGY • December 2006 depends on the age of the haematoma. Total RD characteristically has a V-shaped appearance, with its apex at the optic disk and its extremities toward the cilliary body (Fig. 2). Retinal detachment in axial sections obtained above or below the lens will appear as a homogeneous increase in density of the globe.3 1. Küker W, Ramaekers V. Persistent hyperplastic primary vitreous: MRI. Neuroradiology 1999; 41: 520-522. 2. Harnsberger HR. Diagnostic Imaging, Head and Neck. 1st ed. Manitoba, Canada: Altona, 2004; 11:1-10 to 11:1-11 3. Mafee MF, Peyman GA. Retinal and choroidal detachments: role of magnetic resonance imaging and computed tomography. Radiol Clin North Am 1987; 25; 487-507. 4. McGehee BE, Chaljub G, Shah RK, et al. Bilateral retinal detachment in a patient with Vogt-Koyanagi- Harada syndrome. Am Soc Emerg Radiol 2005; 11: 366-371. a b c Fig. 2. (a) T1-weighted, (b) T2-weighted and (c) FLAIR sequences through the orbit. A ‘V’-shaped abnormal signal is present posteriorly in the left eye with its apex at the optic disc and the arms of the ‘V’ angled towards the ciliary body. Note signal increase in the space outside the ‘V’ on both T1-weighted and FLAIR sequences, in keeping with haemorrhage. Basic Atlas of Sectional Anatomy, 4th edition With Correlated Imaging By Walter J. Bo, PhD; J. Jeffrey Carr, MD; Wayne A. Krueger, PhD; Neil T. Wolfman, MD; and Robert L. Bowden, BA. ISBN 1416001212 · Hardback · 434 Pages · 1600 Illustrations Saunders Gain a rich, 3-dimensional grasp of radiologic anatomy! Features • Pairs digital-quality MR, CT, and ultrasound images with color photographs of the corresponding sagittal and cross- sectional anatomy for every area of the body, showing you how to identify bone, muscle, fat, and other tissues. • Displays diagnostic images and corresponding anatomic photographs on facing pages, making it easy to correlate anatomy with imaging. • Offers more than 1,600 illustrations 300 in full color, almost 1,000 more than the previous edition to explore sectional anatomy in greater detail than ever before. • Presents coronal sections of the head, thorax, abdomen, female pelvis, and male pelvis; oblique coronal and oblique sagittal sections of the shoulder joint; and coronal and sagittal sections of the knee joint. Clinical Neurology for Psychiatrists, 6th edition To Order Contact: Health & Medical Publishing Group Private Bag X1, Pinelands, 7430 Tel: 021 – 6578200 Fax: 021- 6834509 e-mail: carmena@hmpg.co.za / brents@hmpg.co.za By David Myland Kaufman, MD, Professor of Neurology and Psychiatry, Albert Einstein College of Medicine; Director of Neurology, Montefiore Medical Center, Bronx, NY, USA ISBN 1416030743 Ä Hardback Ä 680 Pages Ä 316 Illustrations Saunders Ä Forthcoming Title (December 2006) The sixth edition of this popular favorite is ideal for board review, as well as for clinical reference on neurologic illnesses that can cause or mimic psychiatric symptoms. First it reviews anatomic neurology, describes how to approach patients with suspected neurologic disorders or nervous system diseases, and correlates physical signs. Then it addresses clinical areas such as relevant history, easily performed examinations, differential diagnosis, and management approaches. Abundant line drawings, CTs, MRIs, and EEGs demonstrate key clinical findings to facilitate diagnosis. And, more than 1,600 review questions help you to test and enhance your mastery of the material. Reviews REVIEW OF PREVIOUS EDITION: "This is an excellent, comprehensive textbook that should be in the library of every practicing psychiatrist. Thorough review of this book is more than adequate preparation for the neurology segments of the general psychiatry and geriatric psychiatry examinations. Practicing psychiatrists will find this book extremely useful to have available when they need to look up a neurology complaint or differential diagnosis or simply want to remind themselves of some aspect of the neurological examination or the presentation and management of common neurological diseases. "� The American Journal of Psychiatry Features  Describes each condition's relevant history, neurologic and psychiatric findings, easily performed office and bedside examinations, appropriate lab tests, differential diagnosis, and management options.  Includes over 1,600 review questions and cases to help you prepare for the neurology section of the Psychiatry Board exam.  Uses an accessible writing style and a logical, easy-to-reference organization.  Includes frank discussions of public policy, addressing the important practice issues you face daily. New in this edition  Offers thorough updates to reflect the latest information in the field.  Provides an improved art program which better captures the visual clues that lead to diagnosis.  Features a new two-color format to enhance the book's design and artwork. Clinical Neurology for Psychiatrists, 6th edition To Order Contact: Health & Medical Publishing Group Private Bag X1, Pinelands, 7430 Tel: 021 – 6578200 Fax: 021- 6834509 e-mail: carmena@hmpg.co.za / brents@hmpg.co.za By David Myland Kaufman, MD, Professor of Neurology and Psychiatry, Albert Einstein College of Medicine; Director of Neurology, Montefiore Medical Center, Bronx, NY, USA ISBN 1416030743 Ä Hardback Ä 680 Pages Ä 316 Illustrations Saunders Ä Forthcoming Title (December 2006) The sixth edition of this popular favorite is ideal for board review, as well as for clinical reference on neurologic illnesses that can cause or mimic psychiatric symptoms. First it reviews anatomic neurology, describes how to approach patients with suspected neurologic disorders or nervous system diseases, and correlates physical signs. Then it addresses clinical areas such as relevant history, easily performed examinations, differential diagnosis, and management approaches. Abundant line drawings, CTs, MRIs, and EEGs demonstrate key clinical findings to facilitate diagnosis. And, more than 1,600 review questions help you to test and enhance your mastery of the material. Reviews REVIEW OF PREVIOUS EDITION: "This is an excellent, comprehensive textbook that should be in the library of every practicing psychiatrist. Thorough review of this book is more than adequate preparation for the neurology segments of the general psychiatry and geriatric psychiatry examinations. Practicing psychiatrists will find this book extremely useful to have available when they need to look up a neurology complaint or differential diagnosis or simply want to remind themselves of some aspect of the neurological examination or the presentation and management of common neurological diseases. "� The American Journal of Psychiatry Features  Describes each condition's relevant history, neurologic and psychiatric findings, easily performed office and bedside examinations, appropriate lab tests, differential diagnosis, and management options.  Includes over 1,600 review questions and cases to help you prepare for the neurology section of the Psychiatry Board exam.  Uses an accessible writing style and a logical, easy-to-reference organization.  Includes frank discussions of public policy, addressing the important practice issues you face daily. New in this edition  Offers thorough updates to reflect the latest information in the field.  Provides an improved art program which better captures the visual clues that lead to diagnosis.  Features a new two-color format to enhance the book's design and artwork. pg24-25.indd 25 12/11/06 10:59:22 AM