Early loosening of the stemmed McMinn cup.

The stemmed McMinn cup was used in 26 acetabular reconstructions (median age, 59 [range, 33-85 years]; 21 women) at 5 orthopaedic centers in Sweden between 1995 and 1998. Of the patients, 24 (92%) had severe bone defects (Gustilo-Pasternak grade 3 and 4). At a clinical and radiographic follow-up of median 3 years (range, 1-5 years), 4 (17%) cups were rerevised at 1 (2 cups), 2, and 3 years owing to symptomatic aseptic loosening. Another 8 cups (40%) were radiographically definitely loose and 1 (5%) was probably so. With an overall mechanical failure rate (rerevised plus definitely loose devices) of 43.8% at a minimum 3-year follow-up, the stemmed McMinn cup does not seem to be a reliable solution in acetabular reconstruction.

Computed assisted detection of interval breast cancers.

OBJECTIVES: To examine interval cancer detection rate for a system of computer assisted detection (CAD) and its influence on radiologists' sensitivity/specificity in a screen-like retrospective review situation. MATERIALS AND METHODS: Three screening radiologists reviewed previous screen images of 59 interval cancers mixed with other screening mammograms (ratio 1:5) and non-mixed. Mixed interval cases were interpreted both without and with aid of CAD. RESULTS: CAD detected a number of 14 interval cancers while the three radiologists detected 17, 12 and 11 without and 16, 10 and 13 with CAD. Although CAD specificity was low (38%) no reduction in radiologists' specificity occurred using CAD (73%, 82% and 89% without and 78%, 90% and 92% with CAD). Non-mixed reading increased radiologists' detection rate to 21, 17 and 19 interval cancers respectively. CONCLUSION: Despite sufficiently high sensitivity for CAD alone no increase in radiologist sensitivity (or decrease in specificity) occurred with CAD. Improving CAD specificity, with unaffectedly high sensitivity, should make radiologists more inclined to revise interpretations according to CAD. The potential sensitivity increase, noted when using CAD as a double reader, could be realised in this way.

CT diagnosis of temporal bone anomalies and cochlear implant surgery in CHARGE association.

Children with CHARGE have multiple disabilities. Impairments of vision and hearing, balance problems and facial palsy are common. Few reports have dealt with their radiological temporal bone changes and none with cochlear implant surgery. The pre-operative temporal bone computed tomography (CT) and surgical findings of one child with CHARGE and one with a CHARGE-like condition who have received cochlear implants are reported. The findings include absent semicircular canals, narrow orifice for the cochlear nerve, and abnormalities of the oval and round window, the facial canal and the ossicles. CT can be used as a diagnostic tool as these combinations of temporal bone changes are extremely rare in other materials. Cochlear implants may help these often very isolated children to communicate.

CT findings in tuberculous otomastoiditis. A case report.

PURPOSE: Otomastoiditis is a rare but important manifestation of tuberculosis and is well recognizable when information on its clinical course is considered in connection with the radiographic changes. MATERIAL AND METHOD: A patient with a clinical history of chronic otorrhea, resistant to conventional therapy but without dramatic symptoms, was referred for CT examination. RESULTS: CT revealed widespread soft tissue densities in the tympanic cavity and in the mastoid process, with bone erosions in the latter. Surgery and bacteriology confirmed the diagnosis of Mycobacterium tuberculosis infection. CONCLUSION: CT evidence of widespread bone destruction without clinical signs of aggressive infection should suggest the diagnosis of a mycobacterial process. Early treatment is essential in order to avoid propagation of the disease and lasting loss of function.

Radiological review of incidence breast cancers.

OBJECTIVES: To examine the rate of incidence cancers detectable on review of previous screening mammograms using two reviewing methods. To compare the results with a previous study of interval cancers using the same reviewing methods. SETTING: Almost 50000 women are regularly invited for service screening at Stockholm Söder Hospital. From 1989 to 1993, 119 women were identified with breast cancer detected at screening and the previous round attendance (incidence cancer). METHODS: Screening mammograms, obtained before detection of the incidence cancers, were reviewed first mixed with other screening images (ratio 1:8) and then non-mixed. Reviewers from the screening unit responsible for the mammograms as well as reviewers from other units interpreted all images by both single and double reading. RESULTS: The proportion detected on retrospective review varied between 5% and 50% depending on the review method used and the number of reviewers included to classify a case as truly identified. Generally more cancers were detected when non-mixed samples of mammograms were reviewed than when mixed samples were reviewed (mean increase 23%) and when interpreted by double reading compared with single reading (mean increase 14%). CONCLUSIONS: In an experimental retrospective set up, fewer incidence cancers were identified in mixed than in non-mixed review. Generally more incidence cancers were identified on review (22%) than previously reported for interval cancers (14%), probably reflecting differences in tumour biology and growth. How many women with potentially visible incidence cancers would have benefited from earlier tumour detection still needs to be evaluated.

Two models for radiological reviewing of interval cancers.

OBJECTIVES: To compare two different review methods of examining how many of our interval cancers could be regarded as missed cases (overlooked and misinterpreted owing to observer's error). SETTING: A mass screening programme in Stockholm 1989-91, performed at five independent screening units. 107,846 women attended for screening (70.6% of those invited), and 207 women with interval breast cancers were identified. Interval cancers from two of the units, 104 cases, are reviewed in this study. METHODS: Screening examinations preceding the interval cancer diagnoses were reviewed both mixed with other screening images in a ratio 1:8 and non-mixed. Both internal reviewers (from the two units responsible for the screening mammograms) and external reviewers (from the other units) took part in the study. RESULTS: The proportion regarded as missed cases varied between 7% and 34%, depending on what review method was used, and on the number of reviewers included to identify a case as missed. Mixed reviewing reduced the number identified as missed cases by 50% compared with non-mixed reviewing. Whether the reviewer was internal or external made no difference to the results. CONCLUSIONS: Comparing the rate of missed cases from different studies may be misleading unless the same review method is used. No difference in detection rate could be shown whether the radiologist reviewed images from his/her own screening unit or not. Most of our interval cancers were not regarded as missed cases by either of the two methods.

Ultrasound characteristics of five common soft-tissue tumours in the hand and forearm.

PURPOSE: This retrospective investigation reviewed the ultrasound images of 96 benign soft-tissue tumours of the hand and forearm. The aim of the investigation was to determine whether there was any correlation between the ultrasound picture and the histopathological diagnosis. MATERIAL AND METHODS: Five common types of benign tumour in the hand and forearm were studied: localized villonodular synovites, haemangiomas, lipomas, nerve tumours, and glomus tumours. Only tumours that had been operated on and sent for histopathological examination were investigated. RESULTS AND CONCLUSION: The study found 5 key ultrasound characteristics that were important for differentiating the tumours: existence or not of vessels, existence or not of a capsule, echogenicity, echo structure, and pattern of growth. Taking these traits into consideration should make it easier for the examiner to make the right diagnosis with a reasonable degree of accuracy.

A statistical model for ultrasound diagnosis of soft-tissue tumours in the hand and forearm.

PURPOSE: The ultrasound characteristics of 5 common tumours of the hand and forearm were used to build a statistical model that could assess the weight of each trait or combination of traits in the correct diagnosing of the tumours. The model was used for calculating the first and second diagnostic alternatives. MATERIAL AND METHODS: The basic data of the model were the ultrasound findings in previously presented material on the 5 common benign soft-tissue tumours. The material consisted of 96 tumours: 18 villonodular synovites, 26 haemangiomas, 14 lipomas, 27 nerve tumours, and 11 glomus tumours. To build the statistical model, the ultrasound characteristics that were significant at 5% level were calculated. With stepwise logistic regression, 3 of these were selected as explaining variables. The degree of influence of the explaining variable on the response variable was calculated by way of odds quotients. The material was then analysed by means of the statistical model. The correct diagnosis was calculated as first and second alternatives for each tumour and for the whole material. RESULTS: The diagnostic accuracy for the whole material was 51% in the first choice and 77% in first plus second choices. CONCLUSION: Ultrasound should be the first imaging modality for soft-tissue tumours of the hand. However, MR should also be performed when diagnosis continues to be obscure and when malignancy is suspected.

Postmeningitic labyrinthine ossification primarily affecting the semicircular canals.

In a series of six cochlear-implant candidates, including three small children, labyrinthine ossification in various stages of development was observed at CT. In four of the candidates the ossifying process was more advanced in the semicircular canals than in the cochleae, and in two equally distributed. The ossifying process developed during a period of 4-5 months in two of the children. Asymmetry of its extension was found in four patients. The causative organisms were Hemophilus influenzae and Streptococcus pneumoniae. The radiologic assessment of cochlear-implant candidates should include the semicircular canals where the ossification may start, and herald the development of cochlear ossification.

Anatomical variations of the tympanic and mastoid portions of the facial nerve canal. A radioanatomical investigation.

PURPOSE: To obtain information on the morphology of the tympanic and mastoid portions of the facial nerve canal, and on the appearance of unusual vascular channels and anomalies such as dehiscences. MATERIAL AND METHODS: One hundred and two temporal bone preparations were examined by conventional radiography to evaluate mastoid pneumatization. Of these, 73 were examined by high resolution CT in order to test the ability of the method to detect dehiscences in the bony wall of the tympanic portion of the canal and the accompanying channels along its mastoid portion. Subsequently produced plastic preparations were used to measure the length and width of these 2 portions of the facial canal. RESULTS: Our study reports observations on the three-dimensional morphology of the canal in the plastic casts. The study shows variations in the course and dehiscences of the tympanic portion. Additional bony channels along the mastoid portion are described. These results supplement those in previous investigations. CONCLUSION: The measurement results agree with those of previous investigations. The course of the tympanic portion is S-shaped and has an impression on its upper surface. High resolution CT reproduces dehiscences of the bony canal in a percentage similar to that of microscopical methods and in relevant sites. Pneumatization does not influence the dimensions of the 2 portions.

Diagnosis by ultrasound of dislocated ulnar collateral ligament of the thumb.

The ability of ultrasound to assess a displaced ulnar collateral ligament of the 1st metacarpo-phalangeal (MCP) joint was evaluated. If the ligament is ruptured and displaced proximal to the adductor aponeurosis, a surgical repair should be undertaken to restore stability. Ultrasound accurately diagnosed these lesions in 32/39 operated patients. In 4 cases the ultrasound examination suggested a more severe lesion than was found at operation. In 3 cases a lesser injury was suspected than later proved to be present.

CT-diagnosis of deep-seated lipomas with alarming symptoms.

Deep-seated lipomas can present with symptoms very different from those of the common subcutaneous variety. Rapid growth and nerve encroachment may cause suspicion of malignancy. The case histories as well as the clinical and radiographic findings of 2 patients with alarming symptoms from deep-seated lipomas of hand and forearm, respectively, are described. By means of CT an accurate preoperative diagnosis could be made, and surgery planned accordingly.

Diagnosis of ganglions in the hand and wrist by sonography.

In the practice of hand surgery, imaging of soft tissue structures can provide useful information for diagnosis and preoperative planning. Sonography with high frequency technique giving high spatial resolution is especially rewarding. In a joint project of the Departments of Radiology and Hand Surgery we evaluated the diagnostic accuracy and clinical value of sonographic assessment of ganglions of the hand and wrist. The material comprises 68 soft tissue lesions clinically suspected to be ganglions. Sonography revealed a ganglion in 53 cases, 34 of which went to surgery. The diagnosis was confirmed in every case. One collapsed ganglion was missed. Nonpalpable ganglions causing clinical symptoms could be demonstrated, and a suspected ganglion could sometimes be ruled out in favor of other diagnoses. Sonography could delineate the entire ganglion and often its connection with the joint space.

Osteoid osteomas of the hand. Report of three cases and review of the literature.

Osteoid osteoma is infrequently localized to the hand. Initially the lesion causes unspecific symptoms, and the radiographic changes are discrete. Three cases were seen during a period of 5 years. Bone scintigraphy was a useful diagnostic tool, and CT facilitated the identification of the nidus. One of the lesions was a double nidus osteoid osteoma of the scaphoid bone. Only 12 instances of multifocal osteoid osteomas have been reported, none of which was localized to the carpal bones.

Anatomic variations of the chorda tympani canal.

The anatomic variations of the facial recess are of interest in certain otosurgical procedures. The medial border of the recess is the mastoid portion of the facial nerve canal, and the lateral border is the bony canal of the chorda tympani. These two structures were investigated in 64 polyester casts of temporal bone specimens. The point of exit of the chorda tympani canal from the facial canal was assessed together with the angle, formed between these two nerve channels. As a further way of describing the spaciousness at the facial recess, the distance between the sulcus of the stapedius muscle and the chorda tympani canal was evaluated.

Anatomic variations of the cochlea and relations to other temporal bone structures.

A thorough knowledge of the normal range of variation of anatomy and topography of the cochlea is necessary for optimal reproduction of this structure and correct interpretation of the radiographs. Radiographic identification of incomplete cochlear coils is essential in the diagnosis of congenital malformations such as Modini's deformity. Furthermore, a diagnosis of otosclerosis/otospongiosis has to be based on recognition of changes in the otic capsule. The size and shape of the human cochlea and the normal ranges of variation of its dimensions were evaluated in 95 plastic casts, prepared from temporal bone specimens. The normal range of variation is fairly small, and is not age-dependent. Obvious digression from this range, associated with pertinent clinical symptoms, indicates an abnormality.

Computed tomography with intravenous cholangiography contrast: a method for visualizing choledochal cysts.

Our patient presented with a typical case history and typical symptoms. She also belongs to a group with a high incidence of the disorder. The diagnosis was suspected at ultrasonography, which accurately detected the presence and location of a cyst, but could not establish its origin. Computed tomography is a better diagnostic tool, as it will detect small differences in attenuation and thus identify contrast accumulation in the bile ducts, even when the function of the lever parenchyma is decreased. As scanning is performed in the transverse plane with the patient supine, the layering of contrast medium in the dilated duct is also displayed. In the analysis of our case, the accumulation of biliary contrast medium in the lesion at CT established its origin. The fusiform nature of the dilatation (the type I form of the disorder), was demonstrated at ERCP, after which the operation was performed.

The cochlea and the carotid canal.

The carotid canal conveys a large artery and lies in close topographic relationship to the basal turn of the cochlea. The bony wall between them consists in some cases only of the petrous bone of the otic capsule. It can be as thin as 0.2 mm. In other cases the distance can be more than 6 mm. A systematic assessment of the relationship between these two structures was performed on plastic casts of 173 human temporal bone specimens in order to investigate the range of normal variation. The topography in this region can be visualized by multidirectional tomography or CT.

Caroli's disease in two sisters. Diagnosis by ultrasonography and computed tomography.

Caroli's disease is a rare congenital disease with multiple segmental dilatations of the bile ducts. It may present in two forms: one (the simple form) with segmental dilatations only, and the other with dilatations combined with fibroangioadenomatosis, frequently complicated by portal hypertension. The disease is thought to be recessively inherited, but few familial cases have been reported. We have observed two sisters with the disease, one with the simple form, the other with fibroangioadenomatosis. Their case histories and diagnostic findings, with special reference to ultrasonography and computed tomography, are presented, and the potential for diagnosis by different imaging modalities is discussed.