MRI as a reference standard for suspected scaphoid fractures.

OBJECTIVES: Some have suggested that MRI might be the best reference standard for a true fracture among patients with suspected scaphoid fractures. The primary aim of this study was to determine the rate of false-positive diagnosis of an acute scaphoid fracture in a cohort of healthy volunteers. METHODS: In a prospective study, 33 healthy volunteers were recruited and both wrists of each were scanned, except for 2 volunteers for whom only one wrist was scanned. To simulate the usual clinical context the 64 scans of healthy volunteers were mixed with 60 MRI scans of clinically suspected scaphoid fractures but normal scaphoid radiographs. These 124 MRI scans were blinded and randomly ordered. Five radiologists evaluated the MRI scans independently for the presence or absence of a scaphoid fracture and other injuries according to a standard protocol. RESULTS: To answer the primary question, only the diagnoses from the 64 scans of healthy volunteers were used. The radiologists diagnosed a total of 13 scaphoid fractures; therefore, specificity for diagnosis of scaphoid fracture was 96% (95% confidence interval: range 94-98%). The 5 observers had a moderate interobserver agreement regarding diagnosis of scaphoid fracture in healthy volunteers (multirater κ=0.44; p<0.001). CONCLUSIONS: The specificity of MRI for scaphoid fractures is high (96%), but false-positives do occur. Radiologists have only moderate agreement when interpreting MRI scans from healthy volunteers. MRI is not an adequate reference standard for true fractures among patients with suspected scaphoid fractures.

Imaging of patients with clinically suspected appendicitis in the Netherlands: conclusions of a survey.

The aim of this study was to summarize the extent of variation in imaging strategies in patients clinically suspected of having appendicitis. By means of a written survey, the policies for the imaging management of patients clinically suspected of having appendicitis in the Netherlands were inventoried. A questionnaire was sent to the departments of surgery and radiology of all 105 Dutch hospitals, including the 8 academic medical centres, in March 2006. Questionnaires were returned from 98 hospitals. It was found that, in the work-up of patients suspected of having appendicitis, ultrasound or CT was performed in a minority of hospitals for 50% or more of these patients. In the majority of hospitals, it was carried out for less than 50% of these patients. There is a widespread variability in pre-operative imaging regardless of hospital type. This survey shows that, despite the ubiquitous presence of ultrasound and CT in Dutch hospitals, the pre-operative imaging work-up in patients clinically suspected of having acute appendicitis does not reflect this, being performed in only a minority of patients suspected of having acute appendicitis. Radiologists and surgeons alike should be aware of the positive impact of adjunctive imaging in this group of patients - most importantly lowering the negative appendicectomy rate and also lowering total hospital costs.

Observer variation in MRI for suspected scaphoid fractures.

The aim of this study was to evaluate prospectively the observer variation in the detection of pathology on MRI for suspected acute scaphoid fracture. 79 consecutive MR scans were included to calculate the inter-observer variation. All patients were suspected of having a scaphoid fracture but had no fracture on radiographs. 38 randomly chosen MR scans were used to calculate the intra-observer variation. Four observers, with varying levels of expertise, blinded scored three items: (i) scaphoid fracture, (ii) localization of a scaphoid fracture, and (iii) another fracture. The observer variation was analysed using the kappa statistic. The inter-observer variation for a scaphoid fracture showed substantial agreement. For the localization of a scaphoid fracture and another fracture, there was a moderate and substantial agreement, respectively. The intra-observer variation for a scaphoid fracture had an almost perfect agreement. For the localization of a scaphoid fracture and another fracture, there was an almost perfect and substantial agreement, respectively. In conclusion, the observer variation in MRI of suspected scaphoid fractures was low. The influence of expertise with MRI in daily practice should be taken into consideration. Observers with little experience of MRI will identify all scaphoid fractures but are likely to over-diagnose injuries. Based on these results, it is recommended that all scans are reviewed by an experienced radiologist.

Early magnetic resonance imaging compared with bone scintigraphy in suspected scaphoid fractures.

We evaluated 100 consecutive patients with a suspected scaphoid fracture but without evidence of a fracture on plain radiographs using MRI within 24 hours of injury, and bone scintigraphy three to five days after injury. The reference standard for a true radiologically-occult scaphoid fracture was either a diagnosis of fracture on both MRI and bone scintigraphy, or, in the case of discrepancy, clinical and/or radiological evidence of a fracture. MRI revealed 16 scaphoid and 24 other fractures. Bone scintigraphy showed 28 scaphoid and 40 other fractures. According to the reference standard there were 20 scaphoid fractures. MRI was falsely negative for scaphoid fracture in four patients and bone scintigraphy falsely positive in eight. MRI had a sensitivity of 80% and a specificity of 100%. Bone scintigraphy had a sensitivity of 100% and a specificity of 90%. This study did not confirm that early, short-sequence MRI was superior to bone scintigraphy for the diagnosis of a suspected scaphoid fracture. Bone scintigraphy remains a highly sensitive and reasonably specific investigation for the diagnosis of an occult scaphoid fracture.

Troponin I in predicting cardiac or pulmonary complications and outcome in subarachnoid haemorrhage.

BACKGROUND: Patients with aneurysmal subarachnoid haemorrhage (SAH) are at risk of cardiac and pulmonary complications. Troponin I (cTnI), a reliable marker of myocardial injury, is frequently raised after SAH. AIMS: To investigate the additional value of (cTnI) in predicting cardiac or pulmonary complications and outcome in patients with SAH. METHODS: Admission cTnI was measured in a prospective series of patients admitted within 24 hours of SAH. By means of univariate and multivariate logistic regression models the additional prognostic value of raised cTnI (>0.3 microg/litre) was investigated compared with established prognosticators (clinical condition on admission, age, and amount of blood on admission computed tomography) for predicting the occurrence of pulmonary oedema, pulmonary gas exchange abnormalities, rhythm disturbances, inadequate cardiac performance, a combination of these complications, and poor outcome. Area under the operator characteristic curve (AUC-ROC) was used to assess additional prognostic value. RESULTS: Abnormal cTnI concentrations were found on admission in 35 of 68 patients. Abnormal cTnI concentrations and poor clinical condition independently predicted cardiac or pulmonary complications. After extending the model with World Federation of Neurological Surgeons scale and age in addition to abnormal cTnI, the AUC-ROC improved from 0.70 (95% confidence interval (CI), 0.57 to 0.83) to 0.83 (95% CI, 0.72 to 0.93). Abnormal cTnI also independently predicted poor outcome. The additional prognostic value of cTnI for poor outcome is limited. CONCLUSIONS: cTnI measurement is a powerful predictor for the occurrence of pulmonary and cardiac complications, but does not carry additional prognostic value for clinical outcome in patients with aneurysmal SAH.

[Diagnostic image (187) A teenager in shock three weeks after a gunshot injury. Bleeding from a delayed renal artery pseudoaneurysm]. / Diagnose in beeld (187). Een tiener in shock 3 weken na een hagelschotverwonding. Bloeding uit een A. renalis als laat gevolg van een hagelschotverwonding.

A 15-year-old boy was hospitalised because of injuries caused by a gunshot. After three weeks shock developed due to bleeding from a renal artery pseudoaneurysm.

Cystic lesions accompanying extra-axial tumours.

We examined the mechanism of cyst formation in extra-axial tumours in the central nervous system (CNS). Cyst fluid, cerebrospinal fluid (CSF) and blood plasma were analysed in eight patients with nine peritumoral cysts: four with meningiomas, two with intracranial and two spinal intradural schwannomas. Measuring concentrations of various proteins [albumin, immunoglobulin G (IgG), IgA, alpha 2-macroglobulin and IgM] in cyst fluid, CSF and blood plasma provides insight into the state of the semipermeability of the blood-brain barrier (BBB) and blood-cerebrospinal fluid barrier. Peritumoral cysts accompanying intra-axial brain tumours are the end result of disruption of the BBB and oedema formation. Unlike intra-axial tumours which lie embedded within nervous tissue, extra-axial tumours tend to be separated from nervous tissue by arachnoid and pia mater. High concentrations of proteins were measured in the cyst fluid, approaching blood plasma levels, suggesting a local barrier disruption, and passage across the arachnoid, pia mater and cortical/medullary layer into the CNS parenchyma, leaving the protein concentrations of CSF practically unchanged. We confirmed that very high concentrations of protein are to be found in tumour cysts, plasma proteins forming almost 90% of the total protein in the cyst. We review current hypotheses on the pathogenesis of cysts accompanying neoplasms, particularly meningiomas and schwannomas, and conclude that the majority of proteins in cyst fluid in extra-axial, intradural meningiomas and schwannomas are plasma proteins. This provides a strong argument for pathogenesis of extra-axial intradural tumour cysts in favour of leakage of plasma proteins out of the tumour vessels into the nervous tissue.

Analysis of fluid in cysts accompanying various primary and metastatic brain tumours: proteins, lactate and pH.

There is a growing interest in cystic lesions of the brain. By examining the cyst content of brain tumours more insight into the pathogenesis of cyst formation has been found. In this study, 39 samples of cyst fluid of 34 patients with a cyst accompanying a brain tumour were collected and studied biochemically regarding their protein content, lactate and pH. In this study we investigated the relation between the grade of malignancy and the lactate-concentration and the discrepancy between the high levels of lactate in cysts and their alkaline environment. The results of the measurements of the concentrations of albumin, immunoglobulines (IgG, IgA, IgM) and alpha 2-macroglobulin in cysts compared to those in sera suggest that cyst formation associated with tumour is based upon a disruption of the blood-brain barrier with exudation of plasma proteins into the brain parenchyma resulting in accumulation of fluid (oedema) and eventually in formation of a cyst. There appears to be a positive relation between the grade of malignancy and the concentration of lactate in the cysts with a significant 2-fold increase in lactate concentration in malignant tumour cysts compared to the more benign tumour cysts (p < 0.001) probably on account of aerobic glycolysis with production of lactate by the tumour. The measured pH values in the cysts were above normal, resulting in a discrepancy of the high levels of lactate in the cyst with the alkaline environment and this suggests efflux of H(+)-ions by a Na/H exchange mechanism to compensate for the change of pH.

The pathogenesis of cysts accompanying intra-axial primary and metastatic tumors of the central nervous system.

Recent reports have suggested that cyst formation accompanying astrocytomas in the central nervous system (CNS) is due to an edematous process caused by blood-brain barrier (BBB) disruption and not a result of necrosis. This study is performed to investigate whether the hypothesis of cyst formation based on BBB disruption also applies to various pathologically different intra-axial gliomatous tumors and metastases. By chemical analysis, using immunokinetic nephelometry, isoelectric focussing, cellulose acetate electrophoresis and a biuretic method, the concentrations of albumin, immunoglobulin G (IgG), IgA, alpha2-macroglobulin, IgM and total protein were measured and proportions of concentrations of these proteins were compared in cyst fluid, blood plasma and cerebrospinal fluid (CSF). Our data, based on the chemical analysis of cyst fluid and blood plasma of 37 patients, including 2 ependymomas (one cerebral; one thoracic), 3 oligodendrogliomas, 4 hemangioblastomas, 5 cerebellar astrocytomas and 1 cervical, 1 giant astrocytoma grade one, 1 gangliocytoma, 1 neuroblastoma and 19 metastases (five lung-; two renal-; three breast-; one melanoma-; one thyroid metastasis and seven metastases of unknown origin) present high protein concentrations in the cysts with a highly similar spectrum of proteins in the tumor cyst fluid and blood plasma, suggesting a BBB disruption followed by exudation of plasma proteins into the brain parenchyma with formation of edema and transition of edematous tissue into a cyst accompanying the tumor. Although histopathologically different types of tumor tissue are involved, data suggests that the pathogenesis of cysts accompanying gliomatous tumors and metastases in the CNS is based on BBB disruption and consequent edema, as is the case in the formation of cysts in anaplastic astrocytomas.

Radiographic loosening of cementless threaded acetabular cups. No additional diagnostic value of arthrography in 30 patients.

We compared arthrography with plain radiographs in 30 consecutive patients having a clinical diagnosis of loosening of a smooth-threaded acetabular prosthesis (Mecron, Berlin). Leakage of contrast at the interface between the ring and the bone on the medial side of the prosthesis was seen in 21 patients. Loosening of the cup was also visible on the plane radiographs and loosening was confirmed in all these patients at revision surgery. No false positive arthrographies were seen. In one patient, the arthrography was false negative because of a technical failure. We conclude that no additional information was obtained by arthrography.

Radiographic evaluation of developing instability of the Mecron cementless, threaded acetabular prostheses.

PURPOSE: To evaluate radiographically the history of the Mecron acetabular prosthesis. MATERIAL AND METHODS: The pelvic radiographs of 350 consecutive patients with a smooth threaded acetabular prosthesis type Mecron were retrospectively evaluated (follow-up 1 to 6 years, mean 4 years). A demarcation zone seen at the medial side of the prosthesis was graded from 0 (absent) to 3 (severe). Prostheses with grades 0 and 1 were considered stable and those with grade 3 with or without migration were presumed to be unstable. RESULTS: At five years, 62 (62%) of the cups were unstable and only 23 (23%) were stable. The rate of migration was unacceptably high, and seen in 43 (43%) patients. Migration was only seen in prosthesis with a grade 3 demarcation. CONCLUSIONS: Demarcation visible on radiographs is an important sign of instability of the prosthesis. With the grading system it is possible to evaluate radiographically the history of the prosthesis.

Results of 75 consecutive patients with an acetabular fracture.

From 1988 to 1991, 75 consecutive patients with an acetabular fracture were treated. Follow up was for a minimum of 2 years (average, 3 years; range, 2-5 years). Sixty five patients had a solitary acetabular fracture, and in 10 the acetabular fracture was associated with a pelvic fracture (52 men and 23 women; average age, 46 years; range, 17 to 99 years). Twenty four patients were treated nonoperatively (average age, 46 years; range, 12 to 99 years), and 51 underwent surgery (average age, 45 years; range, 17 to 92 years). The indications for surgery were: displacement of the fracture of > 2 mm; an intraarticular fragment interfering with joint movement; posterior instability of the joint with a luxating femoral head; insufficient roof arc; or to prepare the joint for total hip replacement. The patients were classified according to Letournel. Nonoperative treatment consisted of traction or nonweightbearing mobilization during an average period of 2 weeks. The surgical approaches used were: the Kocher-Langenbeck (22); the ilioinguinal (18); and the extended iliofemoral (4). More than 1 approach was used in 3 cases; external fixation was used in 4. All patients received prophylactic treatment of indomethacin. Six developed heterotopic ossification. Preoperatively, 6 patients had a paresis or paralysis from which 5 recovered. Pre- and postoperative nerve lesions occurred in 3 patients from which 2 recovered. One patient died perioperatively of pulmonary embolus. In 2 patients a collapse of the posterior wall resulted in a total hip replacement. The results were good to excellent according to the d'Aubigne scale in 76% of all patients.

Reproducible radiographs of acetabular prostheses. A method assessed in 35 patients.

35 patients with a smooth, threaded acetabular Mecron type prosthesis were examined with the aid of a table top with wiremarkers and a fixed 30-degree wedge to allow for reproducible positioning. Under fluoroscopic control, pelvic and spot films were made. The inter- and intraobserver variability of anteversion and inclination angle measurements of the prostheses had a standard deviation of less than 1 degree. The method can be applied to other acetabular prostheses as well.

Injuries of the lateral ankle ligaments: classification with tenography and arthrography.

To assess the value of tenography of the peroneal tendon sheaths and of arthrography of the tibiotalar joint for the diagnosis and classification of recent ruptures of the lateral ankle ligaments, the authors performed a prospective study on 108 patients with inversion trauma of the ankle. All patients underwent tenography. Arthrography was performed if results of tenography were negative. All patients with positive tenographic or arthrographic results underwent surgery. Tenography proved to be reliable in the diagnosis of injuries of the calcaneofibular ligament (sensitivity, 88%; specificity, 87%-94%). The positive predictive value of tenography in combination with arthrography was 100% for the diagnosis of lateral ligament ruptures. The authors conclude that a combination of arthrography and tenography is a reliable method for diagnosing recent ruptures of the lateral ankle ligaments and for differentiating between isolated ruptures of the talofibular ligament and combined lesions of both the talofibular and the calcaneofibular ligaments.

Chest radiography in acute traumatic rupture of the thoracic aorta.

Of 123 patients who had suffered blunt trauma to the chest traumatic aortic rupture was eventually confirmed in 61 and absent in 62 patients. The chest radiographs of these patients were examined for 15 signs reported in the literature as being associated with traumatic aortic rupture. Although many individual signs were significantly more frequent in the aortic rupture group they were not useful in differentiating between patients with and those without rupture of the aorta. By using discriminant analysis combining 2 or 3 signs, patients were classified as having aortic rupture or not. The best discrimination between the two groups was obtained using the combined signs of a widened paratracheal stripe, an opacified pulmonary window, a widened right paraspinal interface and a displaced nasogastric tube.

Management of oesophageal perforations; a tailored approach.

The results of treatment of 20 oesophageal perforations were retrospectively studied in 19 consecutive patients. Most complications occurred after endoscopic procedures, after a delay in treatment of more than 12 hours, in patients with intrinsic oesophageal disease and in cases where only drainage procedures were possible. Because of the many factors that influence the outcome of the treatment of oesophageal perforation it is stressed that the therapeutic approach should not be dogmatic, but tailored to the individual patient. Although morbidity is still high, mortality has markedly decreased by this differentiated approach, the only death not being directly related to the perforation. Early recognition remains the most important factor in the prognosis of patients with oesophageal perforation.

Chronic posttraumatic aneurysm of the thoracic aorta: surgically correctable occult threat.

The clinical and radiographic findings of 11 patients with a chronic traumatic aneurysm were reviewed. Each patient had been under medical care at the time of injury but acute aortic rupture was not recognized in any, although several signs of mediastinal hemorrhage were present on the immediate posttraumatic radiographs. The average time between the initial trauma and the detection of the aneurysm was 5.3 years. Seven patients showed no or minimal specific complaints. Four patients showed more or less severe complaints of dysphagia, severe thoracic pain, hoarseness, and dyspnea. In all patients the chest radiograph was abnormal: Four patients showed a mass lesion at the level of the aortic knob. The other seven patients showed contour deformities of the descending aorta, sometimes subtle, with (five) or without (two) calcification. Esophagography and CT were useful in several patients. In the light of the unpredictable course of a chronic traumatic aneurysm and the low operative mortality, early operation after detection is recommended. Preoperative angiography is usually desirable.