A longitudinal insufficiency fracture of the tibia in association with a healed chronic osteomyelitis

Longitudinal stress fracture of the tibia often present with an atypical clinical presentation which can be mistaken for osseous tumor or osteomyelitis. We present a case of longitudinal stress fracture of the tibia which occurred in a patient with healed chronic osteomyelitis of the tibia. Magnetic resonance imaging failed to make the correct diagnosis. Accurate diagnosis was only obtained by helical CT which showed the longitudinal fracture line. Magnetic resonance imaging showed only non-specific signs of bone marrow edema, suggesting recurrence of osteomyelitis. Magnetic resonance imaging can be misleading in the absence of direct visualization of the fracture line. Received: 30 September 1999; Revised: 26 April 2000; Accepted: 2 May 2000     

Meningeal hemangiopericytoma in childhood

Meningeal hemangiopericytoma (MHP) is extremely rare in childhood. Mean age at diagnosis is between 38 and 43 years. We present an 8-year-old boy with MHP of the middle cranial fossa. Imaging findings were indistinguishable from an aggressive bone tumor such as Ewing's sarcoma. Imaging findings are presented and discussed. Our case indicates that MHP should be considered in the differential diagnosis of skull-base tumors despite the fact that MHP is extremely rare in childhood. Received: 8 July 1999; Revised: 28 September 1999; Accepted: 29 September 1999     

MR diagnosis of a congenital abnormality of the thoracic aorta with an aneurysm of the right subclavian artery presenting as a Horner's syndrome in an adult

Congenital abnormality of the aortic arch is a diagnosis made most of the time incidentally in childhood, unless dysphagia or respiratory disorders occur before. A case of a complex aortic arch anomaly with an aneurysm of the right subclavian artery presenting as an isolated Horner's syndrome in an adult is reported herein. Magnetic resonance imaging led to this very unusual diagnosis. Received: 17 March 1999; Revised: 15 July 1999; Accepted: 13 August 1999     

Spontaneous thrombosis of a vein of Galen aneurysmal malformation: possible effects of contrast media

A 5-year-old boy with macrocephaly and mental retardation was referred for radiologic evaluation. After cranial CT and MR imaging, the diagnosis of mural type vein of Galen aneurysmal malformation was established by angiography. Two weeks later, preembolization angiography revealed complete thrombosis of the malformation. Although it is a very rare event, vein of Galen aneurysmal malformation may spontaneously thrombose following diagnostic angiography. Possible effects of contrast media on thrombosis were discussed. Received: 27 April 1999; Revised: 29 September 1999; Accepted: 28 January 2000     

Gleno-humeral instabilities

The purpose of this review is to highlight the most efficient imaging exploratory techniques depicting shoulder instability, to describe its various forms and to point out the findings which can simulate instability. In anterior recurrent dislocation, surgery is indicated and the procedure essentially depends on the importance of glenoid rim lesions. In this case, a standard X-ray evaluation is usually sufficient. The CT arthrography or MRI techniques give more specific details as to the severity of the lesions, particularly soft tissues alterations; however, these data do not alter standard therapeutic protocol. In fixed posterior dislocations, CT scan represents the most pertinent technique to evaluate the size of the humeral head defect and to determine the therapeutic follow-up. In subtle forms of instability, diagnosis or instability direction are not clearly assessed clinically and standard X-ray evaluation is usually unremarkable. In this case, further exploration, such as CT arthrography, MR imaging or MR arthrography, are recommended to confirm the diagnosis of instability and to evaluate its direction. The technique of choice is undoubtedly MR arthrography. Atraumatic voluntary painless subluxations associated with hyperlaxity of the shoulder do not require any specific exploratory method because the findings are generally limited to a capacious axillary pouch. Received: 28 September 1998; Revised: 21 January 1999; Accepted: 22 March 1999     

Magnetic resonance imaging in the assessment of urologic disease: an all-in-one approach

The aim of this study was to evaluate an “all-in-one” MR procedure to examine the kidneys, the renal vascular supply and renal perfusion, and the urinary tract. In 64 patients (58 with urologic disease and 6 healthy volunteers), MR was performed including: (a) T1- and T2-weighted imaging; (b) 3D contrast-enhanced MR angiography (MRA), including the renal arteries, renal veins, as well as renal perfusion; and (c) 3D contrast-enhanced MR urography (MRU) in the coronal and sagittal plane. For the latter, low- and high-resolution images were compared. Prior to gadolinium injection, 0.1 mg/kg body weight of furosemide was administered intravenously. The results were compared with correlative imaging modalities (ultrasonography, intravenous urography, CT), ureterorenoscopy and/or surgical–pathologic findings. Visualization of the renal parenchyma, the vascular supply, and the collecting system was adequate in all cases, both in nondilated and in dilated systems and irrespective of the renal function. One infiltrating urothelial cancer was missed; there was one false-positive urothelial malignancy. Different MR techniques can be combined to establish an all-in-one imaging modality in the assessment of diseases which affect the kidneys and urinary tracts. Continuous refinement of the applied MR techniques and further improvements in spatial resolution is needed to expand the actual imaging possibilities and to create new tracts and challenges in the MR evaluation of urologic disease. Received: 27 September 1999; Revised: 20 January 2000; Accepted: 22 May 2000     

Mediastinal myelolipoma: CT and MRI appearances

A 72-year-old man presented with a mediastinal mass on chest radiograph. Computed tomography and MR imaging showed that the mass consisted of both fatty and small nodular soft tissue components, highly suggestive of an extramedullary hematopoiesis or a myelolipoma. A CT-guided needle biopsy was next performed and confirmed the diagnosis. We discuss the CT and MR imaging appearances of this tumor and usefulness of a CT-guided needle biopsy to avoid surgery in asymptomatic patients. Received: 8 March 1999; Revised: 23 June 1999; Accepted: 25 June 1999     

Intramural leiomyoma of the bladder

Mesodermal tumors of the urinary bladder are rare and the majority of them are malignant. We report a case of an intramural leiomyoma of the bladder presenting with symptoms of a mild lower urinary tract infection. The patient was managed with partial cystectomy and the outcome was excellent. Received: 31 May 1999; Revised: 21 September 1999; Accepted: 21 September 1999     

Imaging of compressive vertebral haemangiomas

Compressive vertebral haemangiomas (VHs) are rare. Correct preoperative diagnosis is useful both for operative planning (since compressive VHs are extremely vascular lesions) and to allow preoperative embolisation. Numerous radiological signs for VHs have been described, but compressive VHs frequently have atypical features. In particular, magnetic resonance features are not well established. We present imaging features in three cases of compressive VH and review the imaging findings in an additional 106 previously published cases. Findings were typical in 52 of 80 plain film (65 %), 33 of 41 computed tomography (80 %) and 13 of 25 magnetic resonance examinations (52 %). The prevalence of previously described imaging features is reported. Awareness of the range of magnetic resonance features is important since this is frequently the initial investigation in patients presenting with symptoms of neural compression. Since computed tomography is typical in 80 % of cases, this is a useful confirmatory test if magnetic resonance features are suspicious but not diagnostic of compressive VH. Received: 6 August 1999; Revised: 4 November 1999; Accepted: 4 November 1999     

MR imaging of lumbar facet joint synovial cysts

The increasing application of magnetic resonance (MR) imaging of the spine has raised the awareness of lumbar facet synovial cysts (LFSC). This well recognised, yet uncommon condition, presents with low back pain and radiculopathy due to the presence of an extradural mass. The commonest affected level is L4/5 with a mild degenerative spondylolisthesis a frequent associated finding. MR imaging is the technique of choice to detect and diagnose a LFSC. This pictorial essay, drawing on experience of 43 cases seen in 40 patients, illustrates the spectrum of appearances that can be encountered and suggest differing causes for the variable signal characteristics exhibited. Computed tomography (CT) can be of value in some cases to aid interpretation of the MR images. In addition, CT facet arthrography by injection of air or iodinated non-ionic contrast medium may be used to confirm the diagnosis in doubtful cases as well as noting whether the patients presenting symptoms can be provoked. A comprehensive review of the existing literature is presented. Received: 22 September 1998; Revised: 29 June 1999; Accepted: 30 June 1999     

Radiological follow-up of inverted papilloma

The aim of this study was to describe cross-sectional imaging features of recurrent papilloma of the nasal fossa and paranasal sinuses and to evaluate the role of MR and CT in the postoperative follow-up of this lesion. Magnetic resonance imaging and CT of ten patients who presented recurrence of inverted papilloma were reviewed and correlated to initial imaging, endoscopy, and surgical reports. Imaging patterns of recurrent inverted papilloma are identical to those of initial tumors and recurrence location is closely related to the site of the former lesion. Magnetic resonance is more efficient than CT for the diagnosis and evaluation of extensions. Magnetic resonance supplies the deficiencies of endoscopy in case of extensions to the frontal sinus or the lateral recess of the antrum, especially if mucosal hyperplasia or sinusitis is associated. Magnetic resonance imaging is the first imaging modality to perform in the follow-up after removal of inverted papilloma. Received: 28 April 1999; Revised: 18 November 1999; Accepted: 19 November 1999     

Various radiological appearances of angiomyolipoinas in the same kidney

A 21-year-old woman with tuberous sclerosis presented with abdominal distension and flank pain. Imaging studies, including CT and MR imaging, revealed bilateral renal mass lesions, containing fat and suggesting the diagnosis of tuberous sclerosis. However the imaging characteristics of one of these lesions differed from the others with no radiologically detectable fat tissue in this solid lesion suggesting renal cell carcinoma. Histopathological examination of this lesion in the left kidney revealed an angiomyolipoma with minimal fat tissue. The radiological diagnosis of angiomyolipomas with minimal fat tissue remains difficult and the differential diagnosis is discussed. Received: 5 October 1998; Revised: 22 December 1998; Accepted: 7 June 1999     

Rectal tumour staging: MR imaging using pelvic phased-array and endorectal coils vs endoscopic ultrasonography

The aim of this study was to compare MR imaging and endoscopic ultrasonography (EUS) for the local staging of rectal tumours. Forty-nine patients were examined on a 1.5-T MR unit using either a pelvic phased-array coil (n = 37) alone or combined with an endorectal coil (n = 12). Sagittal and axial sequences with T2-weighted fast spin-echo and axial T1-weighted spin-echo techniques were employed. The EUS technique was performed using a flexible endosonoscope. The results were compared with findings at histopathological sectioning of the specimen. The T-stage on MR correlated with histopathology in 32 of 49 patients and on EUS in 29 of 49 patients. The N-stage on MR correlated with histopathology in 22 of 49 patients and on EUS in 26 of 49 patients. Tumour penetration of the rectal wall was predicted by MR with 86 % sensitivity and 65 % specificity, and by EUS with 89 % sensitivity and 33 % specificity. Preoperative radiotherapy was administered to 40 of the patients after the examinations which may explain some of the overstaging by MR and EUS. Three patients with surgically and histopathologically confirmed invasion of neighbouring organs in the pelvis were detected preoperatively on MR but none on EUS. Tumour penetration of the rectal wall and local lymph node metastases cannot accurately be predicted with MR or EUS. Magnetic resonance, however, seems to be more useful for preoperative identification of clinically occult advanced disease. Received: 18 February 1999; Revised: 17 September 1999; Accepted: 20 September 1999     

Dedicated extremity MR imaging of the foot and ankle

The purpose of this review is to provide illustrative examples of diseases of the foot and ankle when imaged with a low-field MR imaging system. A retrospective review of 268 foot and ankle examinations, performed in our institution within the past 3 years with a 0.2-T (Artoscan Esaote, Genoa, Italy) dedicated extremity MR system was done. Additionally, illustrative comparison with conventional radiography and high-field MR imaging is presented in patients in whom these examinations were also performed. Although motion artifact limited the value of a few studies, in the majority of examinations low-field MR imaging provided diagnostic image quality for the full spectrum of disorders affecting the foot and ankle and seemed to be a feasible alternative to high-field MR imaging in establishing an accurate diagnosis. Received: 23 November 1998; Revision received: 8 February 1999; Accepted: 4 June 1999     

Presumed capillary telangiectasia of the pons: MRI and follow-up

Capillary telangiectasia is a vascular abnormality primarily of the brainstem. The clinical relevance is unclear as is the association with clearly pathologic findings such as cavernous haemangioma. We report on four cases with capillary telangiectasia proven by follow-up und describe the imaging characteristics. T2 abnormality was only observed in half of the patients as was the presence of a discernable collecting vein. Whereas two cases were incidental findings in neurologically normal persons and one had symptoms clearly attributable to lacunar stroke, one patient may have had symptoms due to the vascular abnormality in the pons. Received: 26 January 1999; Revised: 24 August 1999; Accepted: 23 September 1999     

Imaging of diffuse esophageal leiomyomatosis: two case reports and review of the literature

Diffuse esophageal leiomyomatosis is a rare disorder which may be found in association with leiomyomas in other locations or with other disorders. We report two cases in men, one with associated tracheobronchial involvement, which illustrate the value of imaging in differentiating this entity from other causes of dysphagia and in establishing a diagnosis. Received: 24 December 1998; Revised: 10 May 1999; Accepted: 10 May 1999     

Littoral cell angioma of the spleen: CT and MR imaging appearance

We report a case of littoral cell angioma (LCA) of the spleen, a recently described splenic pathology, which imaging characteristics and pathologic morphology have been discussed only by a few authors. The imaging findings in unenhanced and contrast-enhanced MRI and CT as well as histologic specimen are presented. Diagnosis was made after elective splenectomy. Differential diagnosis of splenic tumors as well as the imaging findings in this particular case are discussed. Received: 7 July 1999; Revised: 18 January 2000; Accepted: 19 January 2000     

Precision of tibial cartilage morphometry with a coronal water-excitation MR sequence

The aim of this study was to analyze the precision of tibial cartilage morphometry, by using a fast, coronal water-excitation sequence with high spatial resolution, to compare the reproducibility of 3D thickness vs volume estimates, and to test the technique in patients with severe osteoarthritis. The tibiae of 8 healthy volunteers and 3 patients selected for total knee arthroplasty were imaged repeatedly with a water-excitation sequence (image time 6 h 19 min, resolution 1.2 × 0.31 × 0.31 mm³), with the knee being repositioned between each replicate acquisition. After 3D reconstruction, the cartilage volume, the mean, and the maximal tibial cartilage thickness were determined by 3D Euclidean distance transformation. In the volunteers, the precision of the volume measurements was 2.3 % (CV%) in the medial and 2.6 % in the lateral tibia. The reproducibility of the mean cartilage thickness was similar (2.6 and 2.5 %, respectively), and that of the maximal thickness lower (6.5 and 4.4 %). The patients showed a considerable reduction in volume and thickness, the precision being comparable with that in the volunteers. We find that, using a new imaging protocol and computational algorithm, it is possible to determine tibial cartilage morphometry with high precision in healthy individuals as well as in patients with osteoarthritis. Received: 15 June 1999; Revised: 7 September 1999; Accepted: 10 September 1999     

MR Imaging features of pelvic mucinous carcinomas

Mucinous carcinomas in the pelvis differ from non-mucinous tumors because of the differences in clinical outcome and imaging appearance. Mucinous rectal carcinomas, for example, are known to be higher in stage at the time of the diagnosis because they are more likely to be infiltrative and show a greater tendency for recurrence. These factors may lead to a poorer prognosis in patients with the mucinous as compared with non-mucinous carcinomas. Mucinous carcinomas of all types typically show high signal intensity on T2-weighted MR images, and therefore mimic other conditions such as necrotic tumors, fluid collections, cysts, or liver hemangiomas. To familiarize readers with the MRI appearance, and to avoid pitfalls, this paper illustrates the MRI features of the mucinous adenocarcinomas in various pelvic organs. Received: 8 February 1999; Revised: 7 October 1999; Accepted: 10 January 2000     

A vascular sarcoid mass mimicking a convexity meningioma

We report a 48-year-old woman with a left posterior temporal extra-axial mass that had the imaging characteristics of a meningioma on preoperative CT, MRI and angiography. However, a biopsy diagnosis of sarcoidosis was made. This case illustrates that dural-based sarcoid masses can be very vascular and radiographically indistinguishable from meningiomas. Characteristic imaging features of extra- and intra-axial sarcoid lesions are discussed. Received: 4 March 1999/Accepted: 11 June 1999