Carpal tunnel syndrome: diagnostic usefulness of sonography

PURPOSE

To prospectively evaluate accuracy of sonography for diagnosis of carpal tunnel syndrome (CTS) in patients clinically suspected of having the disease in one or both hands.

MATERIALS AND METHODS

A prospective cohort of 133 patients suspected of having CTS were referred to a teaching hospital between October 2001 and June 2002 for electrodiagnostic study. One hundred twenty patients (98 women, 22 men; mean age, 49 years; range, 19-83 years) underwent sonography within 1 week after electrodiagnostic study. Radiologist was blinded to electrodiagnostic study results. Seventy-five patients had bilateral symptoms; 23 patients, right-hand symptoms; and 22 patients, left-hand symptoms (total, 195 symptomatic hands). Cross-sectional area of median nerve was measured at three levels: immediately proximal to carpal tunnel inlet, at carpal tunnel inlet, and at carpal tunnel outlet. Flexor retinaculum was used as a landmark to margins of carpal tunnel. Optimal threshold levels (determined with classification and regression tree analysis) for areas proximal to and at tunnel inlet and at tunnel outlet were used to discriminate between patients with and patients without disease. Sensitivity, specificity, and false-positive and false-negative rates were derived on the basis of final diagnosis, which was determined with clinical history and electrodiagnostic study results as reference standard.

RESULTS

For right hands, sonography had sensitivity of 94% (66 of 70); specificity, 65% (17 of 26); false-positive rate, 12% (nine of 75); and false-negative rate, 19% (four of 21) (cutoff, 0.09 cm(2) proximal to tunnel inlet and 0.12 cm(2) at tunnel outlet). For left hands, sensitivity was 83% (53 of 64); specificity, 73% (24 of 33); false-positive rate, 15% (nine of 62); and false-negative rate, 31% (11 of 35) (cutoff, 0.10 cm(2) proximal to tunnel inlet).

CONCLUSION

Sonography is comparable to electrodiagnostic study in diagnosis of CTS and should be considered as initial test of choice for patients suspected of having CTS.

Bone marrow diffusion in osteoporosis: Evaluation with quantitative MR diffusion imaging

PURPOSE

To determine the diffusion of vertebral body marrow with quantitative MR diffusion imaging and to examine whether differences exist between subjects with postmenopausal osteoporosis and premenopausal control subjects.

MATERIALS AND METHODS

A total of 44 consecutive women (mean age, 70 years) with documented bone mineral density (BMD) measured by dual energy x-ray absorptiometry (T-score) and 20 normal subjects (mean age, 28 years) were examined with echo-planar diffusion imaging at 1.5 T using b values of 0, 20, 40, 60, 80, 100, 200, 300, 400, and 500 seconds/mm2. Extravascular diffusion (D) and apparent diffusion coefficient (ADC) were calculated and results from both groups compared.

RESULTS

Both D and ADC values tended to decrease with decreasing BMD. Mean D values were significantly lower in postmenopausal women with reduced BMD (0.42 +/- 0.12 x 10(-3) mm2/second) than normal premenopausal women (0.50 +/- 0.09 x 10(-3) mm2/second). Mean ADC values were significantly lower both in subjects with reduced BMD (0.41 +/- 0.10 x 10(-3) mm2/second) and normal BMD (0.43 +/- 0.08 x 10(-3) mm2/second) compared to normal controls (0.49 +/- 0.07 x 10(-3) mm2/second).

CONCLUSION

Accumulation of fatty bone marrow associated with osteoporosis is reflected by a decrease in D and ADC. Diffusion imaging may prove useful in the study of osteoporosis.

An unusual cause of carpal tunnel syndrome

Tuberculosis is an uncommon cause of carpal tunnel syndrome. We report a patient with systemic lupus erythematosus who developed hand numbness. Ultrasonic, operative and microbiological findings supported the diagnosis of median nerve compression secondary to a tuberculous abscess. The symptoms resolved with surgical excision and antituberculous chemotherapy.

Subcutaneous injection of metallic mercury

Deliberate self-injection of metallic mercury into subcutaneous tissue is uncommon. A 41-year-old lady with a history of schizophrenia was admitted to our hospital after deliberate injection of metallic mercury into her right wrist and antecubital fossa. Physical examination was unremarkable except for the injection marks over right antecubital fossa and wrist. The presence of subcutaneous mercury deposits in her right elbow and wrist was confirmed by X-rays and ultrasound scan. Three days later, erythema, swelling, induration and tenderness were seen over the injection sites. At the operation on day 9, mercury streaks were seen within the brachialis muscle belly, surrounded by friable necrotic tissues along the tract. A similar picture was noted in her right wrist. The necrotic tissues and mercury streaks were removed. The patient had been unco-operative and she only received incomplete treatment with dimercaprol and 2,3-dimercaptosuccinic acid. Her total blood mercury level (normal < 50 nmol/L) decreased from 101-151 nmol/L in the first two weeks to 42 nmol/L 3 months later. Her 24-hour urinary mercury excretion (normal < 10 nmol) changed from 55.7-209.5 nmol in the first 7 weeks to 125.4 nmol 3 months later. This case illustrates that soft tissue metallic mercury can produce local necrosis and may allow continuous absorption with persistent elevations in blood and urinary mercury levels. Therefore, early surgical removal of subcutaneous mercury deposits is required to prevent local complications and minimize the risk of systemic absorption and toxicity.

Rice-body formation in atypical mycobacterial tenosynovitis and bursitis: findings on sonography and MR imaging

OBJECTIVE

This article describes rice bodies found in patients with atypical mycobacterial tenosynovitis and bursitis, emphasizing the sonographic and MR imaging appearances of these small bodies.

CONCLUSION

Rice bodies occur in patients with atypical mycobacterial tenosynovitis and bursitis. When small, rice bodies are better visualized on MR imaging than on sonography, allowing the radiologist to consider appropriate diagnoses.

Anterior shoulder dislocation: quantification of glenoid bone loss with CT

OBJECTIVE

In recurrent anterior shoulder dislocation, glenoid bone loss may predispose the patient to further dislocation and failure of a Bankart repair. This study investigates the quantification of glenoid bone loss in anterior shoulder dislocation using CT.

SUBJECTS AND METHODS

CT examinations were performed on 40 patients (average age, 31 years; range, 13-82 years), comprising 46 shoulders with anterior dislocation and 34 contralateral normal shoulders. Twenty shoulders in 10 healthy subjects were also examined. Both shoulders were examined simultaneously. Image reconstruction included oblique sagittal reformatted images en face to the glenoid fossa. Seven aspects of glenoid fossa shape and size were measured, including the cross-sectional area, maximum width, maximum height, and flattening of the anterior glenoid curvature.

RESULTS

Variable flattening of the anterior glenoid curvature was a feature in 42 (91%) of 46 dislocated shoulders although it was seen in only two (4%) of 54 normal shoulders. Anterior glenoid flattening increased exponentially with an increasing number of dislocations. Anterior glenoid flattening, decreased maximum glenoid width, and decreased maximum width-to-length ratio were the most useful measures of bone loss. Maximum glenoid width was smaller than on the contralateral side in 79% of patients with unilateral dislocation by an average of 3.0 mm (range, 0.1-10 mm) or 10.8% (range, 0.4-32%). Glenoid cross-sectional area was a less useful measure of glenoid bone loss.

CONCLUSION

Flattening of the anterior glenoid curvature is shown in most patients with anterior dislocation. In unilateral dislocation, a comparison of maximum glenoid width with that on the contralateral side was the best discriminator of moderate to severe glenoid bone loss.

Cystic pulmonary metastases from epithelioid cell sarcoma

A patient with cystic pulmonary metastases, from epithelioid sarcoma of the thigh, resulting in bilateral pneumothoraces is presented. The pulmonary metastases superficially resembled pneumomatoceles and were not visible on radiography. Computed tomography examinations over a 10-month period showed no change in the size or number of the cystic metastases, though air fluid levels and pericystic nodular consolidation (probably due to pulmonary hemorrhage) did occur and regress. This case report serves to emphasize that bullous type lesions on thoracic computed tomography in patients with a known sarcoma should be interpreted with particular caution.

Pseudoaneurysm complicating osteochondromas: symptom relief with embolization

Pseudoaneurysm is a recognized vascular complication of osteochondromas. The diagnosis is confirmed by various imaging techniques including ultrasound, magnetic resonance imaging, and conventional angiography. Surgical repair and excision of the adjacent osteochondroma is considered the treatment of choice. The authors report a case of successful transarterial embolization using helical microcoils in the treatment of osteochondroma-related pseudoaneurysm of the superficial femoral artery. It resulted in complete obliteration of blood flow to the pseudoaneurysm and good symptomatic relief before subsequent semielective surgery. No complication was encountered during the procedure. Transarterial embolization is a safe mode of treatment in experienced hands. In patients with contraindications to surgery, embolization may be considered a definitive treatment.

Sonography of plantar fibromatosis

OBJECTIVE

Plantar fibromatosis is a rare benign fibroproliferative disorder of the plantar fascia that can be evaluated on sonography. Our study details the sonographic appearances of plantar fibromatosis.

MATERIALS AND METHODS

We conducted a retrospective review of the clinical presentation, sonographic appearances, and clinical progress in 14 patients (range, 35-85 years; mean age, 53.1 years;) with plantar fibromatosis. Sonography was performed using either a 13-5-MHz multidimensional or 12.5-MHz linear array transducer. The location, sonographic appearances, and size of the plantar fibromatosis nodules were noted and correlated with symptom duration and clinical outcome.

RESULTS

A total of 25 fibromatosis nodules in 19 feet were examined. On sonography, plantar fibromatosis was seen as a discrete fusiform nodular thickening of the plantar fascia, separate from the calcaneal insertion. Approximately one third (36%) of lesions were bilateral, and one quarter (26%) were multiple. All lesions were located either medially (60%) or centrally (40%) in the fascia. Most were hypoechoic (76%), were well defined (64%), and showed no acoustic enhancement (80%) or intrinsic vascularity (92%). No correlation was found between the echogenicity and size of plantar fibromatosis nodules or duration of symptoms (p < 0.01). One quarter of the affected feet had coexistent thickening of the plantar fascia at the calcaneal insertion with no related symptoms.

CONCLUSION

Although the sonographic appearances of plantar fibromatosis vary, the appearances are characteristic enough to allow a specific diagnosis to be made. No clear relationship was found among the sonographic appearances, duration of symptoms, or clinical outcome.

Unusual muscle pain in two patients with diabetic renal failure

We report on two patients with diabetic muscle infarct, a painful musculoskeletal disorder complicating longstanding diabetes with established microangiopathy. Both patients had renal failure that was treated by dialysis. The underlying pathophysiological process was considered to be an arterial vascular event mediated through ischaemia-reperfusion injury. Clinicians should be alert to this condition. T2-weighted magnetic resonance imaging was valuable in establishing the diagnosis.

The clinical efficacy of neoadjuvant chemotherapy in squamous esophageal cancer: a prospective nonrandomized study of pulse and continuous-infusion regimens with Cisplatin and 5-Fluorouracil

BACKGROUND

We evaluated cisplatin and 5-fluorouracil as preoperative adjuvant chemotherapy for patients with locally advanced squamous esophageal cancer and compared two different infusion regimens. The outcomes were also compared with those of our historical control patients treated by surgery alone.

METHODS

From 1991 to 1997, 83 consecutive esophageal cancer patients underwent surgical exploration after completion of two cycles of cisplatin and 5-fluorouracil chemotherapy regimens, either in pulse or in continuous infusion cycles. Outcomes were compared with those of 76 historical control patients. Both groups were comparable in demographic characteristics and tumor stages. The resection rates, operative morbidity, mortality, and survival rates were compared.

RESULTS

Partial response was achieved in 50% of patients who received chemotherapy. There was no chemotherapy-related mortality. The resection, morbidity, and mortality rates and median survival between the surgery-alone group and the chemotherapy group were 71.1% vs. 82%, 51% vs. 55%, and 4% vs. 10.8%, 12.0 vs. 13.5 months, respectively (P >.05). There was also no statistically significant difference between the two regimens.

CONCLUSIONS

Preoperative adjuvant chemotherapy with cisplatin and 5-fluorouracil infusion, in pulse or continuous regimens, followed by surgery for squamous esophageal cancer patients had no added benefit in the overall survival.

Discriminatory sonographic criteria for the diagnosis of carpal tunnel syndrome

OBJECTIVE

Sonographic examination of the median nerve has been suggested as a useful alternative to electrophysiologic study in the diagnosis of carpal tunnel syndrome. To determine its usefulness and the best diagnostic criterion, sonograms of patients with the disease were compared with sonograms of healthy subjects in a case-control study.

METHODS

Patients with carpal tunnel syndrome and asymptomatic controls who were matched for age and sex were enrolled and underwent sonography of the wrists. Eight separate sonographic criteria were analyzed in each wrist. Data from the patient group and the control group were compared to establish optimal diagnostic criteria for carpal tunnel syndrome, using receiver operating characteristic analytic techniques.

RESULTS

Thirty-five patients with carpal tunnel syndrome and 35 asymptomatic controls were examined. Increased cross-sectional area of the median nerve was found to be the most predictive measure of carpal tunnel syndrome, proximal to the tunnel inlet, at the tunnel inlet, and at the tunnel outlet, with significant differences between patients and controls. Using a receiver operating characteristic curve, a cut-off value >0.098 cm(2) at the tunnel inlet provided a diagnostic sensitivity of 89% and a specificity of 83%.

CONCLUSION

Sonographic measurement of the median nerve cross-sectional area is both sensitive and specific for the diagnosis of carpal tunnel syndrome.

Imaging of musculoskeletal tuberculosis: a new look at an old disease

There are certain imaging features that help to differentiate tuberculosis from other bone and joint disorders with a similar presentation. The current authors discuss these distinguishing imaging features particularly with respect to ultrasound, computed tomography, and magnetic resonance imaging. The judicious and appropriate use of these newer imaging modalities coupled with aspiration or biopsy can lead to earlier recognition of musculoskeletal tuberculosis before the onset of debilitating disease.

Influence of staging thoracic computed tomography on radiation therapy planning for esophageal carcinoma

Radiation therapy with concurrent chemotherapy is frequently used as definitive treatment for esophageal carcinoma. Although thoracic computed tomography (CT) is widely used in staging esophageal carcinoma, its application to radiation therapy planning has been regarded as optional rather than mandatory. Conventional radiation therapy planning is esophagogram-based rather than CT-based. The treatment port is generated by adding 5 cm to the proximal and distal margins of the tumor-involved segment as seen on esophagogram performed in the treatment position. Historically, a maximum port length of 15 cm was recommended to avoid excessive treatment morbidity. The authors examined the limitations of such a planning protocol by projecting conventional treatment ports onto the thoracic CT of 75 consecutive newly diagnosed cases of nondisseminated esophageal squamous cell carcinoma. The authors assessed the adequacy of coverage of the primary tumor and metastatic nodes, with respect to data from thoracic CT and neck ultrasonography. It was found that up to 38% of T2-T3 tumors and 30% of short-length (< or =5 cm) tumors had metastatic nodes outside the port. The addition of neck ultrasonography led to identification of an additional 5% of patients with nonpalpable nodes outside the port. It is concluded that the frequency of inadequate tumor coverage using an esophagogram-based planning protocol, with a maximum port length of 15 cm, is unacceptably high. Thoracic CT should be a mandatory rather than optional imaging investigation in guiding radiation therapy planning for esophageal cancer.

Scope and limitations of limb-sparing surgery in childhood sarcomas

The authors reviewed 43 children with high-grade sarcomas of bone and soft tissue who underwent surgery during the past 9 years. Twenty-six patients had osteosarcoma, 7 had Ewing sarcoma, and 10 had soft tissue sarcomas. Patients ranged in age from 4 months to 13 years. Mean follow-up period was 6 years. The feasibility of resection, results of local resection, and failure of local disease control were reviewed. Limb salvage was feasible in 81% of patients. Of the 35 patients undergoing limb salvage, margins were considered adequate in 88% and inadequate in 12%. Limb-sparing resection was not feasible in 19% of patients. Five patients (four with metastatic disease at presentation) did not undergo surgery and were given palliative care; three other patients underwent amputation. The decision of whether to proceed with limb salvage surgery must depend on the aggressiveness of the underlying tumor, its stage, the feasibility of obtaining tumor-free resection margins, and the response to neoadjuvant therapy.

Vertebral osteomyelitis and psoas abscess occurring after obstetric epidural anesthesia

BACKGROUND AND OBJECTIVES

Back pain and infectious complications occasionally occur after epidural anesthesia in obstetrics, and accurate diagnosis can be difficult. We report a patient who developed low back pain soon after obstetric epidural anesthesia and was diagnosed 6 months later with lumbar vertebral osteomyelitis, discitis, and a psoas abscess.

CASE REPORT

A 34-year-old woman developed persistent low back pain after receiving epidural anesthesia for labor analgesia and cesarean delivery. After 6 months, a diagnosis of lumbar vertebral osteomyelitis, discitis, and psoas abscess was made, and surgery was performed. Because of the temporal and anatomical relationships between epidural catheterization and the development of symptoms, the preceding epidural anesthesia was initially suspected as a potential cause. However, because the posterior spinal elements were unaffected and the infectious agent was subsequently identified as tuberculous, the cause was eventually determined as unlikely to be related to the epidural procedure.

CONCLUSION

Investigation of severe back pain after epidural anesthesia should include consideration of infectious causes, such as vertebral osteomyelitis and discitis, which may not be causally related to the epidural catheterization itself.

Closed retrograde nailing of pathological humeral fractures

We treated 19 patients with 21 pathological humeral fractures secondary to metastatic disease. All patients were stabilized using retrograde Ender's nails. Open reduction was required in one patient and mean operative time was 40 min (range 30-65 min). All patients retained satisfactory elbow and shoulder function while 16 patients reported good pain relief. Functional recovery was rated as good in 15 patients, fair in three, and poor in one. In our experience the retrograde technique using Ender's nails provides secure stabilization with minimal morbidity, minimal blood loss, and short operative time, and is well suited for this category of patients.

MR imaging of children's knees

The spectrum of paediatric knee disorders ranges from developmental and growth disorders, traumatic derangement, inflammation, infection, and diffuse marrow disorder to neoplasm. We present in this pictorial review the MR imaging findings used to characterize these various diseases affecting the knee region of children and adolescents.

Sonography of the normal scapholunate ligament and scapholunate joint space

PURPOSE

The aims of this study were to assess the visibility of the normal scapholunate ligament on sonography and to establish the normal scapholunate joint space width in the neutral position and radial and ulnar deviation.

METHODS

Two hundred normal wrists in 100 subjects (55 men and 45 women; mean age, 40 years; range, 19-83 years) were examined with high-resolution sonography (5-12-MHz linear-array transducer). The visibility and thickness of the scapholunate ligament were recorded. The width of the scapholunate joint space, or interval, was measured in the neutral position and radial and ulnar deviation. The width of the distal radius was recorded as a comparative standard for the patients' body habitus.

RESULTS

The dorsal scapholunate ligament was completely (100%) visible in 95 wrists (48%), partially (> or = 50%) visible in 60 (30%), barely (< 50%) visible in 15 (8%), and not visible in 30 (15%). The volar scapholunate ligament was completely visible in 13 wrists (7%), partially visible in 17 (9%), barely visible in 15 (8%), and not visible in 151 (76%). The proximal component of the ligament was not visible in any subject. Measurement of the scapholunate interval was limited by the lack of identifiable anatomic marks for reference. The mean width of the dorsal scapholunate interval was 4.2 mm (range, 2.3-6.3 mm) in the neutral position. The interval did not differ more than 2.5 mm between the left and right wrists. No predictable change in width on ulnar or radial deviation was evident. The mean scapholunate intervals and mean distal radial width were significantly wider in men than in women and on the right side than on the left side.

CONCLUSIONS

The dorsal scapholunate ligament is completely or partially visible in 78% of normal wrists. Its detection following injury may help to exclude the possibility of scapholunate dissociation. There is a quite wide variation in scapholunate interval widths on sonography and an unpredictable response with stress testing. The absence of a visible scapholunate ligament on sonography does not indicate injury.

Alveolar soft-part sarcoma: a rare soft-tissue malignancy with distinctive clinical and radiological features

Alveolar soft-part sarcoma (ASPS) is a rare tumour. Certain distinctive clinical and radiological features suggest the correct diagnosis. There is moderate predilection for young women. ASPS almost always arises in skeletal muscle and occurs most frequently in the lower limbs. There is often a long clinical history and a large mass at presentation. Two young females with ASPS presented with very vascular tumours in the thigh, with prominent intra- and extra-tumoural blood vessels. The imaging findings and the existing literature are reviewed.

Acute elbow trauma in children: spectrum of injury revealed by MR imaging not apparent on radiographs

OBJECTIVE

The objective of this study is to evaluate the frequency and significance of unrecognized bone or soft-tissue injury in pediatric patients with elbow trauma assessed with radiographs alone.

SUBJECTS AND METHODS

Fifty children (32 boys and 18 girls; mean age, 7.3 years; age range, 2-12 years) with acute elbow trauma were examined with radiography and MR imaging. Radiographs were categorized into those showing normal findings, an effusion, an equivocal fracture, or an unequivocal fracture. MR examinations were assessed for an effusion, fracture, transphyseal fracture extension, physeal injury, bone bruising, and ligament or muscle injury. Average clinical follow-up was 1.6 years (range, 6-28 months) after injury.

RESULTS

Radiographs showed normal findings in seven children (14%), an effusion only in 17 children (34%), and an unequivocal or equivocal fracture in 26 children (52%). MR imaging showed an effusion in 48 children (96%); unequivocal fracture in 37 children (74%), including transphyseal fracture in seven children (14%) and other physeal injury in three children (6%); bone bruising in 45 children (90%); ligament injury in six children (14%); and muscle injury in 19 children (38%). A less severe spectrum of injury occurred in children with normal findings on radiographs than in those with an effusion or fracture seen on radiography. Follow-up radiographs did not help in the detection of radiographically occult fractures. MR findings had no appreciable effect on patient treatment and no value in predicting duration of convalescence or clinical outcome at an average of 1.6 years after injury.

CONCLUSION

In children with elbow trauma, MR imaging reveals a broad spectrum of bone and soft-tissue injury beyond that recognizable radiographically. However, the additional information afforded by MR imaging has little bearing on treatment or clinical outcome.

Neck ultrasound in staging squamous oesophageal carcinoma - a high yield technique

AIM

This study evaluates the use of neck ultrasound in staging squamous oesophageal carcinoma.

MATERIALS AND METHODS

A prospective analysis of the clinical, neck ultrasound (US) and thoraco-abdominal computed tomography (CT) findings in 121 patients with squamous oesophageal carcinoma at presentation was performed. The relationship between malignant neck nodes, mediastinal and abdominal adenopathy, location and size of the primary tumour was analysed.

RESULTS

Ten of 121 patients (8%) had clinically palpable neck nodes which were deemed malignant in six (5%) following US and fine-needle aspiration for cytology. Of those 111 patients with no palpable neck nodes, 31 (28%) had malignant nodes shown on US. The more cephalad the location of the primary tumour, the higher the frequency of malignant neck nodes which were found in 80%, 52%, 29% and 9% of cervical, upper thoracic, mid-thoracic and lower thoracic oesophageal tumours, respectively. Eleven (29%) of the 38 patients with malignant neck nodes shown on US had no CT evidence of additional adenopathy in the mediastinum or upper abdomen. Neck US altered TNM staging in 22/121 (18%) patients at presentation.

CONCLUSION

Neck US frequently detects clinically impalpable metastatic nodes leading to altered TNM staging in patients with squamous oesophageal carcinoma. We advocate its routine use when staging squamous oesophageal carcinoma.

Vascularised bone grafting for fibrous dysplasia of the upper limb

We describe our experience with vascularised bone grafting for the treatment of fibrous dysplasia of the upper limb in eight patients, five men and three women, aged between 17 and 36 years. The site was in the humerus in six and the radius in two. Persistent pain, progression of the lesion and pathological fracture with delayed union were the indications for surgical intervention. We used a vascularised fibular graft after curettage of the lesion. Function and radiological progress were serially monitored. Early radiological union of the graft occurred at periods ranging from 8 to 14 weeks. The mean period for reconstitution of the diameter of the bone was 14 months (12 to 18) predominantly through inductive formation of bone around the vascularised graft, which was a prominent feature in all patients. There were no recurrences and none of the grafts sustained a fracture or failed to unite. After operation function was excellent in three patients and good in five. Vascularised bone grafts provide a safe and reliable means of ensuring good continuity of bone with little risk of recurrence and failure.

Sonography compared with radiography in revealing acute rib fracture

OBJECTIVE

This study was undertaken to compare the sensitivities of sonography and radiography for revealing acute rib fracture.

SUBJECTS AND METHODS

Chest radiography and rib sonography were performed on 50 patients with suspected rib fractures. Sonography was performed with a 9- or 12-MHz linear transducer. Fractures were identified by a disruption of the anterior margin of the rib, costochondral junction, or costal cartilage. The incidence, location, and degree of displacement of fractures revealed by radiography and sonography were compared. Sonography was performed again after 3 weeks in 37 subjects.

RESULTS

At presentation, radiographs revealed eight rib fractures in six (12%) of 50 patients and sonography revealed 83 rib fractures in 39 (78%) of 50 patients. Seventy-four (89%) of the 83 sonographically detected fractures were located in the rib, four (5%) were located at the costochondral junction, and five (6%) in the costal cartilage. Repeated sonography after 3 weeks showed evidence of healing in all reexamined fractures. Combining sonography at presentation and after 3 weeks, 88% of subjects had sustained a fracture.

CONCLUSION

Sonography reveals more fractures than does radiography and will reveal fractures in most patients presenting with suspected rib fracture. Further scientific studies are needed to clarify the appropriate role for sonography in rib fracture detection.

Imaging following allograft reconstruction in children with malignant bone tumours

PURPOSE

To determine the nature of the imaging findings following reconstructive surgery using massive allografts in children with malignant bone tumours.

MATERIALS AND METHODS

A retrospective review of the imaging studies and medical charts of 25 consecutive children who received an allograft as part of the management of a malignant bone tumour.

RESULTS

Uncomplicated allografts were sclerotic relative to native bone on radiographs and showed a typical 'tramline' appearance on bone scintigraphy. On MR, the medullary canal of the allograft showed low signal, similar to or greater than skeletal muscle, but less than subcutaneous fat, on 91 % of T1-weighted images. On short-tau inversion recovery images, the medullary canal was inhomogeneous and hyperintense to subcutaneous fat in 70 % and hyperintense to muscle in the remainder. Complications occurred in 68 % of patients and included allograft fractures (36 %), recurrent tumour (20 %), infection (8 %), and non-union or delayed union (8 %). The radiographic findings alone permitted accurate diagnosis of most serious complications. Infection and rejection were difficult to distinguish with any technique. All complications were suspected on clinical and/or radiological grounds before being shown by MR or scintigraphy.

CONCLUSIONS

Allografts, whether normal or complicated, have characteristic imaging findings, except that infection and bone resorption related to rejection and revascularisation are difficult to distinguish. Routine MR and bone scintigraphy appear to contribute little to the management of these patients.

Assessing chemotherapy response of squamous cell oesophageal carcinoma with spiral CT

45 patients with squamous cell carcinoma of the oesophagus were examined prior to, and following, pre-operative chemotherapy by spiral CT. Oesophageal CT was performed following gaseous distention of the oesophagus. TNM stage and perceived resectability on CT before and after chemotherapy were compared and related to surgical resectability and pathological staging. T-stage changed in 26% and N-stage changed in 9% of tumours after chemotherapy. Post-chemotherapy CT predicted pathological T-stage with an accuracy of 88% and N-stage with an accuracy of 84%. Six of 14 tumours considered irresectable on CT pre-chemotherapy were considered resectable on post-chemotherapy CT. Five of these six tumours were resectable at surgery. Post-chemotherapy CT predicted surgical resectability with an accuracy of 88%, the main pitfall being underestimation and overestimation of tracheobronchial invasion. CT prediction of chemotherapy response as judged by change in tumour volume was compared with a quantitative pathological assessment of chemotherapy response. 93% of oesophageal tumours changed volume after chemotherapy with 51% having a volume reduction of > or = 50%. However, no correlation was found between tumour volume reduction on serial CT examinations and either a quantitative pathological assessment of tumour response or patient survival.

MRI evaluation of multifidus muscles in adolescent idiopathic scoliosis

BACKGROUND

The role of the multifidus muscles in the initiation and progression of curve in adolescent idiopathic scoliosis is not fully understood and controversy exists as to the side of the abnormality.

OBJECTIVE

To evaluate on MRI the multifidus muscles at the apex of the major curve in adolescent idiopathic scoliosis to ascertain if the multifidus muscles on the convex or concave side are abnormal and the relationship to curve severity.

MATERIALS AND METHODS

Forty-six patients with adolescent idiopathic scoliosis, separated into two groups, were studied using a 1.5-T MR scanner with the synergy spine coil, employing a modified STIR (short tau inversion recovery) axial sequence obtained at the apex of the major scoliotic curve.

RESULTS

No hyperintense signal change was demonstrated in the convex side multifidus muscles in any patient. In group I, 16 of 18 patients with severe or rapidly progressive curve showed increase in signal intensity in the multifidus muscle on the concave side of the apex of the curve. In group II, of the 15 patients with mild curve (Cobb angle 10-30 degrees), 4 had increased signal intensity in the multifidus muscle on the concave side; of the 13 with more severe curve (Cobb angle greater than 30 degrees), 10 had increase in multifidus signal intensity on the concave side.

CONCLUSIONS

The concave-side multifidus muscle at the apex of a scoliotic curve was morphologically abnormal. A significant association between abnormal signal change and curve severity was also established.

Chronic recurrent multifocal osteomyelitis: a great clinical and radiologic mimic in need of recognition by the pathologist

The spectrum of histopathologic changes in four cases of chronic recurrent multifocal osteomyelitis encountered in our orthopedic outpatient clinic in the past 3 years was studied in conjunction with clinical and radiologic findings. All presented with pain with or without swelling in the affected region. Radiographically, the appearance of the lesions varied from a mixed picture of bone lysis and sclerosis with expansion to sclerosis alone to bone collapse. Bone scintigraphy demonstrated asymptomatic and separate foci of activity in all cases. Prior to biopsy, the clinical and radiologic differential diagnoses included Ewing's sarcoma, metastatic neuroblastoma, hematolymphoid malignancy, Langerhans cell histiocytosis and chronic infection, notably tuberculosis. The spectrum of histopathologic changes ranged from acute (acute inflammatory infiltration, active bone resorption and necrosis, reactive bone formation) to subacute (predominantly lymphocytic and plasma cell infiltration) to chronic inflammation (fibroblastic organization and bony sclerosis). Histologic changes correlated poorly with clinical features, but relatively well with radiologic findings. Lesional excision was performed in one case, cortical saucerization in another, while the final two cases received supportive treatment. All remained well 18-21 months post-therapy. Chronic recurrent multifocal osteomyelitis is a great clinical and radiologic mimic, which merits recognition by the pathologist. Awareness of the spectrum of histologic features encountered enables a correct diagnosis to be made in the appropriate clinical setting. The patient can thus be reassured of a favorable prognosis.

A technique for enhancing union of allograft to host bone

The aim of limb-salvage surgery in malignant bone tumours in children is to restore function and eradicate local disease with as little morbidity as possible. Allografts are associated with a high rate of complications, particularly malunion at the allograft-host junction. We describe a simple technique which enhances union of allograft to host bone taking advantage of the discrepancy in size between the adult allograft and the child's bone. This involves lifting a flap of periosteum before resection from the host bone, which is then telescoped into the allograft medullary canal, which may require internal burring or splitting, for a distance of 1.5 to 2 cm and covering the bone junction with the periosteal flap. This is more stable than conventional end-to-end opposition. For each centimetre of telescoping the surface area available for bony union is increased more than three times. The periosteal flap also augments union. Additional surface fixation with a plate and screws is not necessary. We have used this technique in nine children, in eight of whom there was complete union at a mean of 16 weeks. Delayed union, associated with generalised limb osteoporosis, occurred in one. Early mobilisation, with weight-bearing by three weeks, was possible. There was only one fracture of the allograft.

Primary juxtacortical chondrosarcoma dedifferentiating after 20 years

We present the clinical, radiographic and pathological features of a juxtacortical chondrosarcoma which underwent dedifferentiation to an osteosarcoma in a 47-year-old woman. The tumour, abutting the femoral diaphysis, had initially presented 20 years earlier. Local excision was performed at presentation and again 10 years later, but the tumour recurred on each occasion. Serial radiographs showed cortical saucerisation evolving to cortical buttressing and mounding. After 20 years a dramatic radiographic change heralded tumour dedifferentiation.

Pseudoaneurysm after high tibial osteotomy and limb lengthening

A case of a young man with anterior tibial artery rupture and pseudoaneurysm formation that occurred during lengthening of a scarred limb is presented. Leg length discrepancy occurred because of previous distal femoral and proximal tibial fractures. Two corrective operations were performed 11 and 2 years earlier at another hospital. As limb deformity persisted, distal femoral and proximal tibial osteotomies combined with limb lengthening were performed. The aim was to achieve 120 mm (70 mm femoral, 50 mm tibial) lengthening. The operative and early postoperative course was uneventful. Twenty-six days after surgery (when femoral and tibial lengthening was 13.5 mm and 5.5 mm, respectively), blood began oozing from the operative scar during limb distraction. At 70 days after surgery (when femoral and tibia lengthening was 41.5 mm and 14 mm, respectively), a rupture and pseudoaneurysm of the anterior tibial artery became apparent. Documentation of a normal pulses in the foot after surgery, the late presentation of pseudoaneurysm, and the initiation of bleeding by limb distraction indicate that limb lengthening either aggravated an unrecognized arterial injury or precipitated de novo rupture of the anterior tibial artery scarred from previous trauma. The pseudoaneurysm was treated successfully by transarterial embolization.

Intracortical osteosarcoma

Intracortical osteosarcomas originate in the bone cortex and represent the rarest type of osteosarcoma. We describe the clinical, radiological and histological features of an intracortical osteosarcoma occurring in the femur of a young man and discuss the pertinent features of this tumour compared to those previously reported.

Magnetic resonance imaging of lumbar vertebral apophyseal ring fractures

Posterior lumbar vertebral apophyseal ring fractures are described in three adolescents presenting with severe low back pain, spinal tenderness and lower limb neurological deficit. Magnetic resonance imaging showed severe L4/5 posterior disc protrusion in all three patients. The actual fracture fragment was visualized with difficulty on MRI alone. The diagnosis of apophyseal ring fracture was made by either radiography or CT. Computed tomography delineated the size, shape and site of the fracture fragment. Surgical confirmation was obtained in all cases. Posterior lumbar vertebral apophyseal ring fractures may be difficult to visualize on MR imaging. Careful review of radiographs, supplemented by targeted CT, is necessary for the correct diagnosis and management of this entity.

The conservative management of acute pyogenic iliopsoas abscess in children

We describe three cases of acute pyogenic abscess of the iliopsoas in children treated conservatively. Two patients had image-guided aspiration and one was managed with antibiotics alone. All made a complete recovery. Acute pyogenic abscess of the iliopsoas in children can be treated effectively and safely with intravenous antibiotics and image-guided aspiration of the abscess.

Clinics in diagnostic imaging (29). Thalassaemia major with iron overload

A 5-year-old girl presented with lethargy, anaemia and facial distortion. Both parents had beta-thalassaemia minor. Radiographs confirmed the characteristic features of thalassaemia major. A treatment regime comprising regular blood transfusions was commenced. The basis of the radiographic changes and the current role of magnetic resonance imaging, particularly with respect to assessing iron overload, are emphasized.

Clinics in diagnostic imaging (25). Aggressive vertebral haemangioma

A 30-year-old female presented with a three month history of back pain. Radiographs and computed tomography indicated an aggressive haemangioma of T12 which was confirmed on red cell scintigraphy. The varying imaging appearances of non-aggressive and aggressive vertebral haemangiomas are described, emphasizing the ability of aggressive haemangiomas to mimic metastases on magnetic resonance imaging. The therapeutic role of embolisation as an adjunct ro surgery is stressed.

Uncommon features of abdominal aortoiliac disease

This pictorial review illustrates the cross-sectional imaging of several less common manifestations of aortoiliac disease. Despite their varying clinical features, the imaging appearances with ultrasound, CT and MRI will allow a correct assessment in most cases.

Radiological intervention in Budd-Chiari syndrome: techniques and outcome in 18 patients

We reviewed our experience of the therapeutic role of radiology in Budd-Chiari syndrome. Patients with stenosis and/or occlusion of the main hepatic veins and/or inferior vena cava (IVC) are suitable for radiological intervention (35% in our series). Eighteen patients (mean age 37.4 years) have undergone radiological intervention over the past 8 years. The site of obstruction was the hepatic veins in 12/18 patients while 6/18 patients had both hepatic vein and IVC obstruction, which in two was due to tumour thrombus. One patient had repeated dilatations of a mesocaval shunt; 49 angiographic venous dilatations were performed (18 during initial intervention, 31 on review) including 10 recanalizations of occlusions. A combined transhepatic-transjugular approach was used for 10/49 procedures. Thrombolysis was performed in 5/18 and stent insertion in 6/18 patients. Three serious complications occurred (IVC stent migration, hepatic artery pseudoaneurysm, myocardial puncture). Follow-up, after initial intervention, has continued for a mean of 24.2 months (range 4 days-92 months). Symptoms related to hepatic venous outflow obstruction were fully relieved in 10/18 (56%) patients and partially relieved in 4/18 (22%) patients. Close monitoring (and re-intervention) during the early post-intervention period is needed because 28% of initial venous dilatations failed to provide adequate venous return in the first instance. Once the patient is stabilized regular review is mandatory as HV restenosis is common after 10 months or more follow-up. The efficacy and safety of radiological intervention make it the preferred first line of treatment in selected patients with Budd-Chiari syndrome.