Elizabeth Dick

Ultrasound of the spinal cord in children: its role

Abstract. This article covers the indications for spinal ultrasound including its advantages and disadvantages in comparison with spinal MR. We describe the features of a normal spinal ultrasound and those features which may be found in infants with spinal dysraphism.

Renal artery stenosis: comparative assessment by unenhanced renal artery mra versus contrast-enhanced MRA

ObjectivesTo evaluate steady-state free precession (SSFP) non-contrast-enhanced MR angiography (Unenhanced-MRA) versus conventional contrast-enhanced MR angiography (CE-MRA) in the detection of renal artery stenosis (RAS).MethodsRetrospective analysis of 70 consecutive patients referred for suspected RAS, examined by SSFP Unenhanced-MRA and CE-MRA. Image quality, quality of visible renal arterial segments, presence and grade of RAS were evaluated. The Unenhanced-MRA were compared against reference standard CE-MRA results.Results149 renal arteries were assessed with 21 haemodynamically significant stenoses (≥50% stenosis) demonstrated by CE-MRA. Combined sensitivity and specificity for RAS detection by Unenhanced-MRA was 72.8% and 97.8% respectively. There is substantial correlation for RAS detection between Unenhanced-MRA and CE-MRA with kappa values of between 0.64 and 0.74. There was excellent inter-observer correlation for RAS on Unenhanced-MRA (kappa values 0.82–1.0).ConclusionsOur study has shown Unenhanced-MRA to be a viable alternative to CE-MRA, yielding images equal in quality without the requirement for gadolinium contrast agents. The sensitivity and specificity for the detection of haemodynamically significant stenoses are comparable to CE-MRA. Potentially, Unenhanced-MRA could be used as an initial investigation to avoid performing CE-MRA in patients with normal renal arteries, however we suggest that its real value will lie in being complementary to CE-MRA.

Midfoot and Hindfoot Bone Marrow Edema Identified By Magnetic Resonance Imaging in Feet of Subjects With Diabetes and Neuropathic Ulceration Is Common but of Unknown Clinical Significance

OBJECTIVE We conducted a retrospective cohort study assessing the prevalence and clinical and radiological outcome of remote areas of bone marrow edema on magnetic resonance imaging (MRI) in the feet of subjects with diabetes and neuropathic foot ulceration. RESEARCH DESIGN AND METHODS MRIs performed over 6 years looking for osteomyelitis associated with neuropathic lesions were assessed for remote areas of signal change. RESULTS Seventy MRI studies were assessed. Remote areas of signal change were present in 21 (30%) subjects, involved midfoot or hindfoot in 20 subjects, were associated with younger age and renal replacement therapy, and did not predict future Charcot neuroarthropathy or infection at that site. Repeat MRIs in 11 subjects with such areas found that none had progressed, six had improved, and two had resolved; in 29 subjects without such areas, five had developed new areas. CONCLUSIONS Bone marrow edema in the midfoot and hindfoot of subjects with diabetes and neuropathic lesions is common, often transient, and of unknown significance.

Look away: arterial and venous intravascular embolisation following shotgun injury

We describe two cases of intravascular embolization of shotgun pellets found distant to the entry site of penetrating firearm injury. The cases demonstrate antegrade embolization of a shotgun pellet from neck to right middle cerebral artery, and antegrade followed by retrograde venous embolization through the left lower limb to pelvis. Radiologists and Trauma Physicians should be aware that post shotgun injury, the likelihood of an embolised shot pellet is increased compared to other types of firearm missile injury, and should therefore search away from the site of injury to find such missiles. Shotgun pellets may travel in an antegrade or a retrograde intravascular direction – both were seen in these cases - and may not be clinically obvious. This underscores the importance of a meticuluous search through all images, including CT scout images, for evidence of their presence.

Should all elective knee radiographs requested by general practitioners be performed weight-bearing?

The aims of this study were to: [1] Assess the number of patients with suspected knee osteoarthritis that underwent repeat weight-bearing(WB) knee radiographs in the orthopaedic clinic following initial non-WB radiograph requested by their general practitioner (GP). [2] Confirm whether repeating WB knee views changed radiology reports. [3] Determine the number of London trusts with protocols for routinely performing WB views. A Retrospective cohort study of 1968 patients aged >40 years referred to a London teaching hospital for knee radiographs over 12 months. Radiographs were identified as WB/non-WB. Subsequent repeat WB views performed in those that went on to have an orthopaedic consultation were also documented. A consultant musculoskeletal radiologist reported both images. A proforma containing a likert scale of severity for commonly reported abnormalities in knee osteoarthritis and criteria from the Kellgren and Lawrence scale was used for reporting. London NHS Trusts were surveyed to identify if protocols were in place for performing WB views. A total of 1,968 patients underwent knee radiographs, of which 1922 (97.7%) had initial non-WB radiographs. Of the 56 patients in this group that underwent required repeat WB radiographs, joint space narrowing was reported as more severe on WB versus non-WB radiographs (p = 0.035). Only 54% of departments routinely performed WB radiographs. Few patients (2.3%) referred by GPs have WB radiographs requested. Some of those referred for a specialist opinion required repeat WB views. Nearly half of London hospitals do not routinely perform WB radiographs. This represents a significant financial burden to the NHS, increased radiation exposure and wasted patient/clinician time. We propose that all GP requested knee radiographs be performed as WB unless otherwise stated.

Part II - Dorsal wrist pain and swelling post trauma 2

DiagnosisTraumatic lipohaematoma of the extensor tendon sheaths(compartments 2–4) post distal radial fracture.DiscussionIn the same way that identification of a lipohaemarthrosisalerts the reading radiologist to the presence of an intra-articular fracture, the visualisation of a lipohaematoma ofthe tendon sheath after trauma may herald the presence offracture extending into an osseous groove for a tendon. Italso indicates injury to the tendon sheath, and raises thepossibility of associated tendon injury, which may warrantfurther assessment of the affected tendon with magneticresonance imaging.A 29-year-old man presented post cyclist vs car accident.CTshowed a comminuted distal radial fracture. As shown inFig. 3 of the case presentation, a fracture line cleavedcompletely through the base of Lister’s tubercle (largerarrow) with disruption of the floor of the fourth compart-ment by an acute angled sharp fracture fragment (smallerarrow). Fracture lines extended into the grooves for extensorpollicis longus (3rd extensor compartment) and extensordigitorum (4th extensor compartment). A separate fracturepassed into the grooves for extensor carpi radialis longusand brevis (2nd extensor compartment). The edges of thefracture fragments were sharply angulated and disrupted theosseous grooves for the 3rd and 4th compartment tendons.The medullary cavity of the distal radius appeared open tothe tendon sheaths of both the 3rd and 4th extensor compart-ments. An oblique sagittal fracture line was also seenextending from the volar surface of the radius through thearticular surface. A small lipohaemarthrosis of the radio-carpal joint was present. Further distally, within the tendonsheaths of the second, third and fourth extensor compart-ments prominent fat–fluid levels within the tendon sheathswere seen, accounting for the gross soft tissue swelling seenon the radiograph. The lipohaematoma was most volumi-nous within the distal third and fourth compartment sheaths,and comparatively small in the second compartmentsheaths. The average Hounsfield Unit density of the upper(and, by volume, larger) layer within the tendon sheaths wasapproximately −90, consistent with the presence of fat.Magnetic resonance imaging obtained 4 days after theinjury showed fat-fluid layers within the non-dependentaspect of the sheaths of the second, third and fourth com-partments. A layer of high T1 signal within the non-dependent aspect of the sheaths (part 1 figure 2 - arrow),which completely saturated on T2 fat suppression and cor-responded to the position of the −90 HU density materialseen on the CT, was present, confirming the presence of fat.The distal radial fracture is also evident on this image. Therewas focal irregular high T2 signal seen along the deep radialside surface of tendons of the extensor digitorum and exten-sor pollicis longus adjacent to the sharp fracture edges,consistent with tendon abrasion, but no frank split or rupturewas seen. The dependent portion of the lipohaematomashowed signal characteristics consistent with a mixture offluid and blood. Figure 4 of this article shows a fracture lineevident in the distal radius, which appears to have disruptedthe tendon sheath and is opening into the floor of the fourth

Dorsal wrist pain and swelling post trauma

A 29-year-old male presented immediately following a cyclist versus car accident with right wrist pain and swelling. The swelling was prominent, and located primarily over the dorsal aspect of the wrist and hand. A CT image from a study at the time of presentation is shown in Fig. 1, and a sagittal T1-weighted MRI 4 days after injury in Fig. 2. What is the cause of the swelling at the dorsal aspect of the wrist and hand?

Laser and Focused Ultrasound Ablation of Primary and Secondary Liver Tumours

Many patients with primary and secondary liver tumours are unsuitable for surgical resection but would benefit from minimally invasive therapy. The particular advantages of minimally invasive therapy are (i) the procedure can usually be performed under local anaesthesia, as a day-or overnight-case, (ii) the mortality and morbidity associated with it are very low, especially when compared to hepatic surgery [1]. The aim of thermal tumour ablation is to destroy the entire tumour (ideally with a margin of lcm of normal tissue) but to avoid collateral damage to adjacent vital structures. Image guidance using MRI can help to achieve this goal by monitoring optimal fibre placement and assessing the extent of in vivo heating produced in target tissues as well as demonstrating the amount of necrosis produced at follow up.