ABSTRACTS COMPUTED T O M O G R A P H I C ASSESSMENT OF SOFT TISSUE ABNORMALITIES FOLLOWING FRACTURES OF THE CALCANEUM S. A. BRADLEY and A. M. DAVIES
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SHOULD MRI REPLACE A R T H R O G R A P H Y OF THE KNEE? A. F. WATKINSON, N. R. BOEREE, C. A C K R O Y D , C. JOHNSON and I. WATT
Birmingham Accident Hospital, Birmingham
Bristol Royal Infirmary, Southmead Hospital and Bristol MRI Centre, Bristol
In this prospective study high resolution CT was performed in axial and coronal planes on 32 patients with 39 acute calcaneal fractures, and 63 patients with 73 fractures, more than 6 months old. The series comprised of 72 males and 23 females with an age range of 12 to 82 years (mean 51.2 years). The images were viewed on a soft tissue window. Thirty-one (79%) of the acute fractures were intra-articular. Of these 21 had bony encroachment, subluxation or dislocation o f the peroneal tendons. Medially four had bony encroachment of the abductor hallucis longus muscle and two had partial rupture of the flexor hallucis longus tendon. Fifty-one (70%) o f the chronic fractures were intra-articular. Of these the peroneal tendons were abnormally sited in 31 and structurally abnormal in 33. Medially bony encroachment was present in two cases and structural abnormalities in six. Muscle wasting was observed in 16 cases. The incidence of tendon abnormalities is similar in both groups, although the pattern varies. The results of the two groups are compared and the importance o f soft tissue changes following fractures of the calcaneum is discussed.
The value of magnetic resonance imaging (MRI) in the investigation of patients with suspected meniscal or cruciate injuries has been evaluated by comparison with arthroscopy. A series of 203 consecutive patients have been investigated by MRI for suspected derangement o f the menisci or cruciates. A 0.5 Tesla magnet was used using 2D FT series. One hundred and thirty-three subsequently underwent arthroscopy, no invasive procedure being required for the remainder, the majority of which had had normal MRI findings. Using arthroscopy as the gold standard MRI was found to be as accurate as the best quoted results for arthrography (95%) for the medial meniscus, lateral meniscus and anterior cruciate ligament. The posterior cruciate ligament was well demonstrated by MRI but is difficult to see arthroscopically. MRI is concluded to be a reliable, safe and comfortable means of investigating the knee with an equivalent accuracy of the best quoted arthrographic series. When available, MRI should be the investigation of choice. REAL TIME DIGITAL P E R I P H E R A L ANGIOGRAPHY S. C. W A R D and J. F. DYET
THE CT FINDINGS IN PRIMARY L Y M P H O M A O F BONE C. COUSINS, P. J. M c M I L L A N , E. M. BESSEL and B. J. PRESTON
City, University and General Hospitals, Nottingham Primary lymphoma of bone is an unusual extranodal presentation of non-Hodgkin lymphoma, accounting for approximately 5% of all extranodal lymphomas and fewer than 1% of primary bone tumours. It should be distinguished from other malignant bone tumours because of the more favourable prognosis. We describe the CT and radiographic findings in nine cases of primary lymphoma of bone. The nine patients, aged 40 to 82 years, had CT following a bone biopsy diagnosis of non-Hodgkin lymphoma. In all cases, the lesions were destructive and slightly expansile, with a large associated soft tissue mass in eight of the nine cases. CT was performed to stage the disease and there was no evidence of thoracic, abdominal or pelvic adenopathy, although in one case a smallaortic lymph node less than 1 cm diameter was demonstrated. The CT features described are not pathognomonic but are characteristic of lymphoma of bone and awareness of the findings may facilitate correct early diagnosis.
Hull Royal Infirmary, Kingston upon Hull A new technique for performing peripheral angiography is described, using real time pulsed digital imaging. The equipment used is a Philips Digital Cardiac Imaging system, operated via an Optimus M200 console. The patient lies supine on a fully floating table top, with an absorption wedge and bolus bag between his legs to reduce flare. The common femoral artery is cannulated using standard Seldinger technique, and a 4.5 F catheter is introduced into the lower aorta. A pump injector is loaded with 60 ml of either Ioxaglate 320 or Iopromide 300, according to allergic history. Digital acquisition is commenced at the lower aorta and the contrast is injected. The table is moved to follow the contrast column as it passes down the legs. Information is acquired at 12.5 frames per second onto a 512 x 512 matrix. Repeat runs, oblique views, or subtraction sequences may be performed, but are rarely required. Selected images are transferred to hard copy using a Dupont Opti Imager. The software allows for post-processing of the images and severity of stenoses may be calculated. The technique is quick and uncomplicated and provides a rapid method for accurate assessment of the peripheral arterial tree. MRI ENABLES DIFFERENTIATION OF MIDBRA1N DEFORMITY F R O M INTRINSIC BRAINSTEM NEOPLASIA J. V. H U N T E R , B. D. YOUL and I. F. MOSELEY
SUPERIOR TIBIO-FIBULAR G A N G L I A - A S P E C T R U M OF IMAGING ABNORMALITIES WITH CLINICAL CORRELATION D. GRIER, V. CASSAR-PULLICINO, and I. W. M c C A L L
The Robert Jones & Agnes Hunt Orthopaedic Hospital, Oswestry The clinical and radiological features of 18 patients with superior tibiofibular ganglia are presented. The imaging methods encompass plain film radiography, superior tibio-fibular joint arthrography,.computed tomography, ultrasound, and magnetic resonance imaging. The unusual spectrum of clinical presentation is correlated with the radiological appearances and the optimum mode of imaging. The results show that diagnostic and therapeutic difficulties arise from the tendency to spread, often by a peduncle into the neighbouring tissues. The swellings migrate from the joint and may be subcutaneous, subperiosteal, intra-muscular, or may involve the common peroneal nerve by compression or infiltration. In the absence of a swelling, the .exclusion of such a lesion by the imaging methods described, is essential in the clinical setting of tibial compartment syndromes, as well as spinal nerve root compression. The radiological characteristics are reproducible with frequent demonstration o f asymptomatic contralateral disease. Pre-operative delineation of the presence, extent and communications are essential requirements to reduce the significant recurrence rate. The aetiological naechanism o f spread and therapeutic implications based on these radiological features are discussed.
National Hospital for Neurology and Neurosurgery, Queen Square, London The distinction between Chiari malformation and intrinsic brainstem neoplasm in adults can be difficult. We report the value of MRI in resolving this difficulty. Case 1. 40-year-old male presented with diplopia and right-sided facial pain. CT showed homogeneous bulkiness of the lower pons interpreted as a pontine glioma. MRI showed type I Chiari malformation. Cervical images showed syringomyelia. Case 2. 57-year-old male presented with progressive brainstem symptoms and signs. CT demonstrated a brainstem mass. MRI showed tonsillar ectopia and a s y r i n x - appearances consistent with Chiari I malformation. Case 3.,64-year-old male presented with abnormal brainstem signs. CT scan was reported as normal. Gadolinium DTPA enhanced MRI revealed midbrain deformity without neoplasia. There was mild cerebellar ectopia but.no syrinx. We describe midbrain deformity in three patients in association with features of the Chiari I malformation. In all three cases CT was misleading, resulting in a diagnosis of intrinsic neoplasm in cases 1 and 2. MRI enabled demonstration of the soft tissue abnormalities, including syrinx in cases 1 and 2. The lack of altered signal argued against glioma. Clinical follow-up has confirmed this impression. These cases illustrate the significant contribution of MRI to the diagnosis of cervico-medullary abnormality and in particular its ability to distinguish midbrain dysplasia from neoplasia.