Bilateral xanthogranulomatous perinephritis without renal parenchymal involvement

A case of isolated bilateral xanthogranulomatous perinephritis, which presented as a symmetrical irregular perirenal rim of soft tissue, is reported. Differential diagnosis and image features on ultrasound, computed tomography, and magnetic resonance are discussed. Received: 20 May 1999; Revised: 20 July 1999; Accepted: 22 July 1999     

Nontraumatic dens fracture in a patient with lymphangiomatosis: radiographic, CT, and MR findings

Lymphangiomatosis is a rare condition characterized by benign angiomatous growth of lymphatic tissue. Bone infiltration may result in lytic lesions surrounded by sclerotic margins of varying thickness. We report a nontraumatic fracture of the dens in a female patient. Conventional radiographs and computed tomographic and magnetic resonance images are shown. The use of computed tomography and magnetic resonance imaging is highly recommended for investigating bone lesions of lymphangiomatosis, since, as occurred with our patient, conventional radiographs may not reveal all bone lesions in this disorder.     

Elastofibroma of the neck

Elastofibromas are benign lesions of the chest wall. We describe the first reported case of elastofibroma in the neck. Imaging features as well as location of the lesion were atypical. On computed tomography and magnetic resonance imaging the lesion contained a marked preponderance of fat, because the lesion arose within fat. Received: 12 November 1998 Revision requested: 18 November 1998 Revision received: 16 August 1999 Accepted: 24 August 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     

Renal carcinoma: diagnosis of venous invasion with Gd-enhanced MR venography

The aim of this study was to evaluate the usefulness of gadolinium-enhanced time-of-flight magnetic resonance venography (MRV) in the diagnosis of bland thrombosis/tumoral invasion in the preoperative assessment of renal cell carcinoma. Preoperative precontrast and enhanced GRE fast low-angle shot (FLASH) images of 36 patients with renal adenocarcinoma were reviewed and compared with pre- and post-contrast T1-weighted images. All patients underwent surgery, and MR findings were blindly and prospectively compared with surgical and pathologic data, considered the standard. Renal vein and vena cava were involved in 17 and 9 patients, respectively; right atrial extension was present in one patient. Precontrast spin-echo (SE) and FLASH images were 88 % sensitive and 100 % specific in the detection of venous involvement, respectively, and enhanced FLASH images 100 % sensitive and 96 % specific. The nature of thrombus (neoplastic or bland) was more accurately assessed (McNemar's, p < 0.05) with FLASH-enhanced MR images (sensitivity 89 %; specificity 96 %) than with SE and precontrast FLASH images (sensitivity 79 %; specificity 94 %). Our data suggest that use of Gd-enhanced MRV might improve preoperative assessment of vascular involvement in renal carcinoma. Received: 7 September 1999; Revised: 26 November 1999; Accepted: 26 November 1999     

Middle cerebral artery variations detected by magnetic resonance angiography

Middle cerebral artery (MCA) variations are found incidentally on cranial magnetic resonance angiography (MRA). Our goal was to examine the incidence and types of MCA variations detected by MRA. Between April 1996 and March 1999, cranial MRA was performed in 432 cases at our institution. Most of the patients examined had or were suspected to have cerebrovascular disease. After excluding 7 patients with moyamoya disease, we retrospectively reviewed 425 MRA results. A 1.5-T scanner was used in all studies, and maximum-intensity projection images obtained using the three-dimensional time-of-flight technique were displayed stereoscopically. In the 425 patients MRA revealed 16 anomalous MCAs, including 9 duplicated MCAs, 5 accessory MCAs, and 2 fenestrated MCAs, which is a rate of 3.8 %. Thus, although the clinical significance is not great, we found a relatively high incidence of anomalous MCAs on MRA. We stress that knowledge and recognition of these variations are useful and important during the interpretation of cranial MRA. Received: 3 August 1999; Revised: 22 November 1999; Accepted: 22 November 1999     

Ruptured adrenal artery aneurysm: a case report

A case of ruptured adrenal artery aneurysm is presented. The ultrasound, computed tomography and selective renal angiography findings are described in detail. Aneurysms of adrenal arteries are particularly rare. Early diagnosis is important because of their tendency towards rupture and subsequent high mortality rate. Received: 12 November 1998; Revised: 10 March 1999; Accepted: 13 April 1999     

Diagnostic imaging of aortic diseases

Summary The aim of this overview is the comparison between noninvasive tomographic imaging modalities such as surface echocardiography, transesophageal echocardiography, X-ray computed tomography and magnetic resonance imaging with the previous gold standard angiography in the setting of acute and chronic aortic diseases. Methods: The groundwork for the comparison between various noninvasive modalities is the validation of findings with angiography or intraoperative and histopathological results. Results and conclusions: Noninvasive modalities such as transesophageal echocardiography, X-ray computed tomography and magnetic resonance imaging are suitable methods for reliable diagnosis or exclusion of aortic dissection both in the ascending and descending segment of the thoracic aorta. Other more rare pathologies of the aorta such as intramural hemorrhage as a precursor of dissection, aortic ulcers, aneurysms as well as congenital and posttraumatic lesions may also be subjected to transesophageal echocardiography or magnetic resonance imaging with excellent sensitivity and specificity; both techniques have also proven to be safe procedures in critically ill patients and have, in our view, replaced angiography for the diagnosis of acute aortic syndromes. Thus, in acute aortic diseases invasive angiographic procedures should be relegated to a complementary role, while transesophageal echocardiography, X-ray computed tomography (especially helical CT) in acute, and magnetic resonance imaging in chronic cases represent prefered diagnostic options. In addition to primary diagnostics the noninvasive approaches using transesophageal echocardiography and magnetic resonance imaging are superbly suitable for serial follow-up imaging in all forms of aortic pathology. Eingegangen am 23. Januar 1997 Angenommen am 23. Januar 1997     

Tumors of the cardiac valves: imaging findings in magnetic resonance imaging, electron beam computed tomography, and echocardiography

We describe the findings from various cross-sectional imaging modalities in patients with cardiac valve adherent masses. The techniques are discussed, and imaging findings are compared with the results of cardiac surgery. All three patients had neurological symptoms and/or cardiac murmurs. Transthoracic and/or transesophageal echocardiography revealed the cardiac mass in all three. For differentiation of thrombus and cardiac neoplasm magnetic resonance imaging (MRI) was also performed in all three patients and electron-beam computed tomography (EBCT) in two. Fast segmented cine gradient-echo MRI techniques provided mass depiction in all patients, while T1-weighted spin-echo imaging failed in mass detection in one patient. None of the patients showed evidence of valve regurgitation or stenosis in flow sensitive cine MRI. EBCT excluded mass calcifications in both patients and reliably demonstrated the valve attached lesions. Although echocardiography is the modality of choice in evaluating cardiac masses and especially valve attached masses, MRI and EBCT provide additional information about tissue characteristics and allows an excellent overview of the cardiac and paracardiac morphology. Fast segmented cine gradient-echo MRI is especially able to depict even small tumors attached to rapidly moving cardiac valves, and valve competence can be easily assessed within the same examination. Received: 17 December 1998; Revision received: 1 June 1999; Accepted: 10 August 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     

Fluorine-18 fluorodeoxyglucose positron emission tomography in infectious bone diseases: results of histologically confirmed cases

The aim of this study was to evaluate the clinical use of fluorine-18 fluorodeoxyglucose positron emission tomography (FDG-PET) in acute and chronic osteomyelitis and inflammatory spondylitis. The study population comprised 21 patients suspected of having acute or chronic osteomyelitis or inflammatory spondylitis. Fifteen of these patients subsequently underwent surgery. FDG-PET results were correlated with histopathological findings. The remaining six patients, who underwent conservative therapy, were excluded from any further evaluation due to the lack of histopathological data. The histopathological findings revealed osteomyelitis or inflammatory spondylitis in all 15 patients: seven patients had acute osteomyelitis and eight patients had chronic osteomyelitis or inflammatory spondylitis. FDG-PET yielded 15 true-positive results. The tracer uptake correlated with the histopathological findings in each case. Bone scintigraphy performed in 11 patients yielded ten true-positive results and one false-negative result. Follow-up carried out on two patients revealed normal or clearly reduced tracer uptake, which correlated with a normalisation of clinical data. In early postoperative follow-up it was impossible to differentiate between postsurgical reactive changes and further infection using FDG-PET. It is concluded that acute and chronic osteomyelitis of the peripheral as well as the central skeleton can be detected using FDG-PET. Osteomyelitis can be differentiated from soft tissue infection surrounding the bone. Unlike computed tomography and magnetic resonance imaging, FDG-PET is not affected by metal implants used for fixing fractures. FDG-PET demonstrated promising initial results with respect to treatment monitoring. Nevertheless, in the early postoperative phase FDG-PET seems to be of limited value owing to unspecific tracer uptake. Received 4 November 1999 and in revised form 20 January 2000     

Abdominal wall hernias: imaging with spiral CT

Computed tomography is an accurate method of identifying the various types of abdominal wall hernias, especially if they are clinically occult, and of distinguishing them from other diseases such as hematomas, abscesses and neoplasia. In this study we examined the CT images of 94 patients affected by abdominal wall hernias observed over a period of 6 years. Computed tomography clearly demonstrates the anatomical site of the hernial sac, the content and any occlusive bowel complications due to incarceration or strangulation. Clinical diagnosis of external hernias is particularly difficult in obese patients or in those with laparotic scars. In these cases abdominal imaging is essential for a correct preoperative diagnosis and to determine the most effective treatment. Received: 20 May 1999; Revised: 10 August 1999; Accepted: 13 August 1999     

Primary renal and retroperitoneal actinomycosis

A case of the rare condition of renal and retroperitoneal actinomycosis is presented. The clinical and imaging (ultrasonography and computed tomography) findings are described and attention is drawn to the diagnostic difficulties in this rare disease. Received: 26 October 1998; Revised: 5 February 1999; Accepted: 7 May 1999     

Sclerotic bone metastases from sarcomatoid renal cell carcinoma

We present a case of sarcomatoid renal cell carcinoma with multiple sclerotic skeletal metastatic lesions. Renal cell carcinoma is frequently metastatic at presentation, with a high incidence of skeletal involvement, classically described as osteolytic. However, sclerotic or osteoblastic metastatic skeletal lesions from renal cell carcinoma are rare, with only two previous reports identified in the literature, neither of which involved the sarcomatoid variant of renal cell carcinoma. In our case the sclerotic metastases were characterized by bone scan, computed tomography (CT), magnetic resonance imaging (MRI), and histologic analysis. Received: 8 April 1999 Revision requested: 27 May 1999 Revision received: 24 June 1999 Accepted: 29 June 1999     

Hemorrhagic brain abscess in infective endocarditis

We report a case of infective endocarditis (IE) that presented with acute neurological deterioration due to bleeding into a brain abscess disseminated from mitral valve vegetation. The patient recovered following surgical evacuation of hemorrhage/abscess and prolonged systemic administration of antibiotics. Although IE causes various neurological complications including intracranial hemorrhage, hemorrhagic brain abscess in patients with IE is rare. Appropriate combination of diagnostic modalities including computed tomography, magnetic resonance imaging, cardiac ultrasonography, and cerebral angiography, together with careful evaluation of the clinical history, leads to accurate diagnosis and treatment of patients with IE presenting with neurological complications.     

MR urography in children: current status and future development

The normal anatomy and many pathologies of the pediatric genitourinary system can be assessed with different imaging modalities. Most of them are based on the use of ionizing radiation and/or invasive techniques. The contribution of magnetic resonance imaging in this regard has opened new ways of approaching pathological conditions in this patient group. The addition of the newly developed rapid techniques has enhanced the superiority of MRI, and both morphological and functional evaluation of the genitourinary system can be achieved. There are different factors on which rely the optimization and the efficiency of magnetic resonance urography (MRU). Of importance is adequate patient immobilization and the use of optimal imaging sequences. The rapid technical development, including the advent of the post-processing respiratory navigator, allows acquisition of high-quality images independent of the patient's respiratory rate. In the future, it is expected that MRU, due to its non-use of ionizing radiation, will become the most important tool in the diagnostic work-up of genitourinary pathologies in infants and small children. Received: 1 June 1999; Revision received: 9 August 1999; Accepted: 11 August 1999     

Percutaneous nephrostomy: placement under laser guidance and real-time CT fluoroscopy

The purpose of this paper is to present our experience with real-time computed tomography (CT) fluoroscopy guided percutaneous nephrostomy (PNT) and to describe this technique involving puncture under laser guidance. We attempted 30 placements in 25 patients: puncture was directed by laser guidance and placement of the tube was made under real time CT fluoroscopy. 25 procedures were performed in prone position and 5 procedures in the supine position. The time necessary for the procedure ranged from 10 to 45 min (mean 25 min). The average duration of CT fluoroscopy per placement was 49 seconds (range 7–110 s). The PNT placement was successful as a sole procedure including puncture and catheter placement in 24 of 30 cases; in the remainder of cases, puncture was performed under CT guidance but the catheter was definitively positioned in conventional fluoroscopy. The CT fluoroscopy technique allows routine, efficient and safe PNT placement, especially when encountering difficult access to the pelvicaliceal system. Received: 9 June 1999; Revised: 12 November 1999; Accepted: 12 November 1999     

MRI of the brain in cerebrotendinous xanthomatosis (van Bogaert-Scherer-Epstein disease)

The clinical, biochemical and magnetic resonance imaging findings of two patients with cerebrotendinous xanthomatosis are reported. This is a rare hereditary disease. Early recognition of this entity is important in view of the existing treatment possibilities. Magnetic resonance imaging findings typically include a bilateral and almost symmetrical increase of the signal intensity on the T2-weighted images in the cerebellar and periventricular cerebral white matter, the basal ganglia, the dentate nuclei and the brainstem as well as cerebellar and cerebral atrophy. Received: 18 January 1999; Revised: 3 June 1999; Accepted: 7 June 1999     

Intra-articular lipoma with osteochondroid metaplasia in the knee joint

We describe a case of lipoma with osteochondroid metaplasia in the knee joint. Although the location of the lesion and radiographic findings were unusual, computed tomography and magnetic resonance imaging were useful in characterizing adipose, cartilaginous and osseous tissue components within the lesion. Received: 12 October 2000 Revision requested: 3 November 2000 Revision received: 23 December 2000 Accepted: 28 December 2000