Magnetic resonance imaging in patients with granulomatosis with polyangiitis (Wegener's) and subglottic stenosis

OBJECTIVE

To evaluate the ability of MRI to detect subglottic stenosis and to differentiate between active and inactive subglottic inflammation in patients with granulomatosis with polyangiitis (GPA).

MATERIALS AND METHODS

MRI studies of the larynx of 18 GPA patients with suspected SGS were included. The MRI protocol included T1- and T2-weighted and STIR-sequences, dynamic contrast enhancement (DCE) and diffusion weighted imaging (DWI). Two independent observers reviewed the MR images. SGS were identified and quantified, inflammatory activity was assessed using edema imaging, DCE and DWI. Final MRI diagnoses were compared to the clinical, laryngoscopic and histopathologic results.

RESULTS

MRI confirmed SGS in all GPA patients with significant narrowing of the airway lumen and thickening of subglottic wall. Assessing the subglottic inflammatory activity, MRI showed a sensitivity of 87.5 % and a specificity of 60.0 %. Interrater agreement was κ = 0.769. Of the different MR technical approaches tested, edema imaging was most sensitive and specific. DWI led to significant differences in the apparent diffusion coefficient between active and inactive subglottic inflammation. No significant differences were found with DCE imaging.

CONCLUSION

MR imaging has shown the ability to detect and grade SGS in patients with GPA. It non-invasively assesses the status of inflammatory activity utilizing edema sensitive sequences and DWI.

Correlation of serum level of high mobility group box 1 with the burden of granulomatous inflammation in granulomatosis with polyangiitis (Wegener's)

OBJECTIVES

To investigate the correlation of serum levels of high mobility group box 1 (HMGB1) with the extent of granulomatous inflammation in granulomatosis with polyangiitis (GPA).

METHODS

From 169 patients with GPA, 17 patients with granulomatous inflammation, without evidence of vasculitis were identified and 36 patients without measurable 'granuloma' formation. HMGB1 serum levels were determined and compared between the two groups, using a Mann-Whitney U test. Serum levels of 26 healthy individuals served as controls. In a further 21 patients with GPA with a pulmonary granulomatous manifestation from the study population, CT volumetry of 'granuloma' was performed. Volumes were compared with serum levels of HMGB1 (Spearman rank order test).

RESULTS

Serum levels of HMGB1 were significantly higher in patients with predominant granulomatous disease than in patients without measurable 'granuloma' manifestations (6.44 ± 4.53 ng/ml vs 3.85 ± 2.88 ng/ml; p=0.0107). In both groups, levels of HMGB1 were significantly higher than in controls (2.34 ± 2.01 ng/ml; p<0.01). A positive correlation of HMGB1 serum levels with volumes of pulmonary 'granuloma' (r=0.761, p<0.0017) was seen.

CONCLUSIONS

HMGB1 serum levels are significantly higher in GPA with predominant granulomatous manifestations and correlate with volumes of pulmonary 'granuloma'. HMGB1 may be used as a marker of the burden of granulomatous inflammation in GPA.

Comparison of whole body MR angiography at 1.5 and 3 Tesla in patients with hereditary hyperlipidemia

BACKGROUND

Patients suffering from hereditary hyperlipidemia have a high risk for premature cardiovascular disease and death as a consequence of accelerated atherosclerosis.

PURPOSE

To prospectively and intra-individually compare image quality and detectability of stenoses in contrast enhanced whole-body MRA (WBMRA) at 1.5 and 3 Tesla (T) in patients with hereditary hyperlipidemia.

MATERIAL AND METHODS

Twenty-seven patients with hereditary hyperlipidemia received a 1.5 and 3 T gadopentetate dimeglumine contrast-enhanced WBMRA. Twenty-three defined arterial segments were analyzed regarding depiction of target vessels and image quality according to a 5-point-scale ('not evaluable' to 'excellent'). Wilcoxon matched pair test was performed for comparison. Forty-three defined arterial segments were analyzed for the degree of stenosis (0%, 1-49%, 50-99% and 100%) as well as vessel alterations such as aneurysms. Chi-square test was performed for comparison.

RESULTS

1.5 T and 3 T scans yielded WBMRA with diagnostic quality in all patients. In seven of 23 arterial segments (30.4%) image quality was rated significantly higher at 3 T, whereas there was no significant difference in the remaining 16 segments between WBMRA at 1.5 T and 3 T. All relevant stenoses (n = 5), occlusions (n = 6), and aneurysms (n = 3) were evaluated similarly at both field strengths.

CONCLUSION

WBMRA can be performed at 1.5 T and 3 T with diagnostic image quality. Image quality was significantly higher at 3 T than at 1.5 T in only 30.4% of the arterial segments. In order to effectively take advantage of the higher field strength, further optimization of sequence parameters and injection protocols for WBMRA at 3 T is necessary.

[Imaging techniques for giant cell arteritis. Ultrasound and MRI]

This article summarizes the examination technique, typical findings, interpretation and limitations of ultrasound diagnosis in patients with giant cell arteritis. Colour-coded sonography of the temporal artery has gained increasing attention. If experienced ultrasound examiners are available, diagnosis of giant cell arteritis in patients with a typical clinical constellation can be made based solely on sonographic findings, in particular by a hypoechogenic halo. The hitherto probably under-diagnosed large vessel variant of giant cell arteritis shows characteristic findings with a simple and quick ultrasound examination of the proximal arm arteries. High resolution MRI has been shown to be a promising technique for non-invasive imaging of giant cell arteritis. Mural inflammatory changes of the superficial temporal arteries can be depicted and the cranial involvement pattern can be readily assessed and in combination with MR angiography extracranial involvement can be determined within the same investigation. Aortitis is a feared complication of giant cell arteritis but can be detected and inflammatory stenoses of the aortic branch vessels can also be revealed. In the hands of an experienced operator ultrasonography can be regarded as the non-invasive imaging modality of first choice whereas MRI is more expensive and may not be as widely available. However, its imaging acquisition is standardized and is more observer-independent. Reading of the images is a routine task for a vascular radiologist and larger areas of the vasculature can be simultaneously assessed.

Mural inflammatory hyperenhancement in MRI of giant cell (temporal) arteritis resolves under corticosteroid treatment

OBJECTIVE

To determine the effect of corticosteroid treatment on mural inflammatory hyperenhancement in MRI in GCA.

METHODS

MRI of the superficial temporal artery with sub-millimetre in-plane spatial resolution (195 x 260 microm) was performed in 17 patients with proven GCA at the initiation of corticosteroid treatment and after 16 months of therapy. Visual MRI scores for mural inflammation were correlated with clinical and laboratory findings.

RESULTS

Intensity of inflammatory hyperenhancement decreased significantly under corticosteroid therapy (2.3 +/- 0.6 vs 0.5 +/- 0.6, P < 0.001, with MRI score >2 indicating vasculitis). This finding correlated with the clinical and serological remission in 15/17 patients. Of the two patients with active disease, one had persisting mural inflammation in MRI indicative of relapsing disease. The other patient presenting with signs of polymyalgia rheumatica had no inflammatory changes of the superficial temporal arteries on MRI scan at follow-up.

CONCLUSIONS

Mural contrast enhancement in high-resolution MRI is pronounced in active disease and decreases under corticosteroid treatment, correlating well with laboratory remission.

Bilateral ce-MR angiography of the hands at 3.0 T and 1.5 T: intraindividual comparison of quantitative and qualitative image parameters in healthy volunteers

The purpose of this study was to determine the benefit of bilateral contrast-enhanced MR angiography (ce-MRA) of the hands at 3.0 Tesla (T) compared with an established 1.5-T technique in healthy volunteers. Intraindividual bilateral ce-MRA of the hands was performed at 1.5 T and 3.0 T in 14 healthy volunteers using a timed ultra-fast GRE sequence featuring parallel acquisition. The evaluation comprised measurement of the vessel signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR), rating of the image quality and the assessment of artefacts and venous contamination. At 3.0 T, SNR improved up to 95% and CNR up to 129%. The image quality of the larger inflow arteries, the palm arches and common digital arteries was good or sufficient at either magnetic field strengths. However, 3.0-T MRA was clearly superior in the depiction of the digital arteries. Ce-MRA of the hand clearly profits from the use of 3.0 T. Compared with 1.5 T, a substantial increase of CNR is found resulting in a significantly better delineation of the small digital arteries. Saturation affects more the SNR of the perivascular tissue than the contrast-enhanced blood, and thus leads to a marked increase of CNR at 3.0.

Imaging findings in a 3-year-old girl with type III pleuropulmonary blastoma

Pleuropulmonary blastoma (PPB) is a rare dysembryonic intrathoracic neoplasm in children. It is a malignant tumour originating from the mesenchyme with a poor prognosis. We report on a 3-year-old girl who presented with respiratory symptoms and was diagnosed as having a type III PPB according to histological results attained by open biopsy. Imaging by CT and MRI revealed the exact size of the tumour involving the left lower lobe with displacement of the mediastinum and the diaphragm. Additional FDG-PET was important to evaluate tumour vitality and to decide the time of surgery, which was performed after 12 weeks of chemotherapy with the CWS2002P protocol. After R0 resection without complications and postoperative chemotherapy, the child continues to be in complete remission. This case underlines the importance of radical surgery of the aggressive neoplasm in combination with chemotherapy and the usefulness of multimodal imaging for the optimal planning of local therapy.

Diagnostic value of high-resolution MR imaging in giant cell arteritis

BACKGROUND AND PURPOSE

Clinical indications of giant cell arteritis may be unspecific, and noninvasive diagnosis is often difficult. This study investigated the hypothesis that high-resolution MR imaging of the superficial cranial arteries is a noninvasive imaging technique that can detect the occurrence of giant cell arteritis.

MATERIALS AND METHODS

Contrast-enhanced, high-resolution MR imaging was performed on 64 consecutive patients with suspected giant cell arteritis. Mural thickness, lumen diameter, and a mural contrast enhancement score were assessed with T1-weighted spin-echo images with submillimeter in-plane spatial resolution. The final rheumatologist's diagnosis according to the clinical criteria of the American College of Rheumatology including laboratory tests and results of temporal artery biopsies from 32 patients was used as a "gold standard" for the evaluation of the MR imaging findings.

RESULTS

All of the examinations provided diagnostic image quality. Evaluation of the mural inflammatory MR imaging signs for diagnosing vasculitis resulted in a sensitivity of 80.6% and a specificity of 97.0%. In comparison, histology results alone showed a sensitivity of 77.8% and specificity of 100%. The mean wall thickness increased significantly from 0.39 mm (+/-0.18 mm) to 0.74 mm (+/-0.32 mm; P < .001), and the lumen diameter decreased significantly from 0.84 mm (+/-0.29 mm) to 0.65 mm (+/-0.38 mm; P < .05) for patients with giant cell arteritis.

CONCLUSION

Contrast-enhanced, high-resolution MR imaging allows noninvasive assessment of mural inflammation in giant cell arteritis with good diagnostic certainty. Measures of mural thickening and contrast enhancement can be obtained in these small vessels and provide valuable vasculitic MR imaging findings.

Sliding multislice MRI for abdominal staging of rectal gastrointestinal stromal tumours

Anorectal gastrointestinal stromal tumours (GISTs) are uncommon mesenchymal neoplasms. The objective of this report was to demonstrate the value of sliding multislice (SMS) as an upcoming method of continuously moving table MRI, providing detailed abdominal staging of rectal GISTs. Integration of SMS into a high-resolution pelvic MR imaging protocol allows for both detailed assessment of rectal GISTs and depiction of the entire abdomen with high image quality. The staging of liver, malignant lymph nodes and bone metastases is now possible, prolonging pelvic MRI for only one minute.

State of the art 3D MR-cholangiopancreatography for tumor detection

With the use of current multislice techniques for MR cholangiopancreatography various upper abdominal pathologies including pancreatic carcinoma, Klatskin tumor and metastatic spread can be non invasively depicted. Respiratory gating allows free breathing of the patient, which increases patient comfort, while excellent image quality can be achieved. In this concise pictorial report, state of the art MRCP images of various cancer entities including sequence descriptons are presented.

Magnetresonanztomografie der Arteriitis temporalis Horton

Giant cell (temporal) arteritis is a diagnostic challenge. Blindness is a dreaded complication, especially if high-dose steroid treatment is delayed. With an optimized MR protocol, noninvasive diagnosis of giant cell arteritis is facilitated. Submillimeter in-plane resolution makes it possible to distinguish healthy segments from inflamed segments. The lumen and arterial wall can be depicted in high detail. Post-contrast high-resolution MRI visualizes the superficial cranial arteries bilaterally and simultaneously, allowing assessment of the cranial involvement pattern. In combination with MR angiography of the aortic arch and supra-aortic arteries, the extracranial involvement pattern can be demonstrated in a single comprehensive MR examination assessing the cranial, cervical and thoracic vasculature. Good diagnostic image quality can be achieved at 1.5 Tesla and at 3 Tesla. However, due to higher signal-to-noise ratios, image quality seems to be superior at 3 Tesla. Over the course of successful long-term treatment, MR signs of mural inflammation decrease significantly and eventually vanish entirely. In contrast to color-coded Duplex sonography, which is a comparatively cost-efficient imaging modality, acquisition of high-resolution MRI is almost independent of the investigator's expertise. Compared to positron emission tomography with 18F-fluoro-2-deoxy-D-glucose, which is a very sensitive whole-body screening tool for detecting extracranial involvement of large vessel vasculitis, MRI allows visualization and assessment of both the superficial cranial arteries in high detail and the extracranial large artery involvement in the same investigation.

[Injuries of the cervical spine with Forestier's disease. Problems in the diagnostic and surgical management]

The incidence of diffuse idiopathic sceletal hyperostosis (DISH) is described in men more than 50 years old up to 25% and in women up to 15%. Even little trauma in patients with DISH often leads to injuries of the spine, especially the cervical spine. In many cases MRI is necessary to find the injury in this anatomically modified spine. It is often difficult to detect the injury by plane radiographs or even CT. Based on two cases of cervical spine fractures in patients with DISH we will describe the difficulties and specialities in the diagnostics and surgical treatment of injuries of the cervical spine in patients with DISH. In the one case we stabilized a patient with an odontoid fracture type Andersson II, the other case was a traumatic spondylolisthesis C4/C5. Both cases were treated operatively, the odontoid fracture was stabilized by a single screw, the spodylolisthesis by a ventral plate. If there are modifications in the spinal anatomy by degenerative diseases like DISH or spondylitis ankylosans, it is important to perform an intense search for injuries of the spine. In many cases MRI is indicated to detect the injury because plane radiographs and CT are not sensitive enough. For the planning of the operation it is important to meet concerns to the thick anterior longitudinal ligament and to use screws, that are long enough because the use of standard instruments is often not successful.

Die Analyse aortaler Hämodynamik und Gefäßwandparameter mittels fluss-sensitiver in-vivo 4D-MRT bei 3 Tesla

Modern phase contrast MR imaging at 3 Tesla allows the depiction of 3D morphology as well as the acquisition of time-resolved blood flow velocities in 3 directions. In combination with state-of-the-art visualization and data processing software, the qualitative and quantitative analysis of hemodynamic changes associated with vascular pathologies is possible. The 4D nature of the acquired data permits free orientation within the vascular system of interest and offers the opportunity to quantify blood flow and derived vessel wall parameters at any desired location within the data volume without being dependent on predefined 2D slices. The technique has the potential of overcoming the limitations of current diagnostic strategies and of implementing new diagnostic parameters. In light of the recent discussions regarding the influence of the wall shear stress and the oscillatory shear index on the genesis of arteriosclerosis and dilatative vascular processes, flow-sensitive 4D MRI may provide the missing diagnostic link. Instead of relying on experience-based parameters such as aneurysm size, new hemodynamic considerations can deepen our understanding of vascular pathologies. This overview reviews the underlying methodology at 3T, the literature on time-resolved 3D MR velocity mapping, and presents case examples. By presenting the pre- and postoperative assessment of hemodynamics in a thoracic aortic aneurysm and the detailed analysis of blood flow in a patient with coarctation we underline the potential of time-resolved 3D phase contrast MR at 3T for hemodynamic assessment of vascular pathologies, especially in the thoracic aorta.

Influence of corticosteroid treatment on MRI findings in giant cell arteritis

Giant cell arteritis (GCA) remains a diagnostic challenge. With the use of a high-resolution MRI protocol, visualization of the superficial cranial arteries is feasible and mural inflammation can be assessed noninvasively. Until today, it is not known how soon inflammatory signals in diagnostic MR imaging vanish after initiation of treatment. Here, we report sequential MR imaging findings during the initial weeks of corticosteroid treatment in a 79-year-old female patient with histologically proven GCA. Mural inflammatory changes decreased within the first 2 weeks and have almost entirely vanished after 2 1/2 months of continued treatment. Moreover, MR angiography revealed sequential stenoses of the subclavian artery, which improved in variable extent with some residuals despite high dose steroid medication. This report underlines the value of high-resolution MRI in diagnosis and follow-up of GCA and illustrates the potential of MRI to detect and monitor intra- and extra-cranial involvement patterns of GCA in high detail.

Clinical and radiological findings after different treatment of odontoid fractures type Anderson II and III

PURPOSE OF THE STUDY

In the period from 06/00 to 08/02, 31 patients with odontoid fractures type Anderson II and III were treated and stastically recorded. 25 patients were followed up; the progess of 24, documented in detail radiographically, were evaluated independently by a traumatologist and by a radiologist. The usual time of immobilization when treating odontoid fractures type Anderson type II and III with the halo-fixator is 12 weeks. For this 12 weeks that it is worn, objective assessment of bone healing is performed radiographically and the results critically considered in terms of the length of time that the halo-fixator should be worn and whether this duration should be altered on the basis of the clinical and radiological results obtained.

MATERIALS AND METHODS

16 patients with an odontoid fracture type Anderson type II were treated partly with a halo-fixator and partly by additional operative stabilization. 15 patients with a type III fracture were treated in a halo over 12 weeks. At the time of the accident the patients to be treated had to have conventional radiographic examination and a CT scan as well as a position check following reduction. After 4, 8 and 12 weeks radiographic and CT investigation was repeated. These findings were evaluated independently by a surgeon and a radiologist. The clinical follow-up was carried out using the VAS Score and, in addition, the general activity level before and after the accident was recorded in a similar way on the Tegner/Lysholm subjective activity score.

RESULTS

In most cases, according to the CT scan, the osseous bridging decreased again between the 8th and 12th weeks, as defined by resorption zones seen during the fracture healing period. Radiological evidence of complete osseous bridging was only seen after 12 weeks in three cases.

CONCLUSION

Conventional radiography does not seem to us to be the most suitable technical means to evaluate osseous healing in odontoid fractures. The CT is more reliable for this. According to our radiological results, osseous healing of different types of odontoid fractures takes more than 12 weeks. Despite of its known complications, the halo fixator is still a good instrument for the treatment of odontoid fractures.

Fast and quantitative high-resolution magnetic resonance imaging of the optic nerve at 3.0 tesla

A novel and fast magnetic resonance imaging approach for imaging the optic nerve and the surrounding cerebrospinal fluid sheath is presented. The method provides high contrast between the nerve and cerebrospinal fluid and allows for accurate quantification of the optic nerve and its cerebrospinal fluid sheath diameter within 1.5 seconds scan time. Results of a volunteer study illustrate that measurements can reliably be performed even in the distal part of the intraorbital optic nerve track. Accuracy of quantification of the new technique is demonstrated by the assessment of changes in the optic nerve and CSF sheath diameter between straight gaze and 30 degrees abduction.

3-T MRI reveals cranial and thoracic inflammatory changes in giant cell arteritis

Giant cell arteritis (GCA) is a diagnostic challenge. The correct diagnosis is needed for immediate initiation of corticosteroid treatment since blindness is a dreaded complication. Typically, the superficial cranial arteries are affected by this granulomatous vasculitis of large- and medium-sized arteries. However, GCA is not limited to the cranial arteries. Involvement of various arteries such as the cervical and thoracic arteries can also occur. Here, we report a case of histologically proven GCA with cranial and extracranial involvement. We illustrate the usefulness of a comprehensive vascular high-resolution magnetic resonance imaging examination that combines assessment of mural inflammatory changes of the small temporal and occipital arteries with the evaluation of extracranial vasculature to assist in the difficult non-invasive diagnosis and to determine the extent of this inflammatory disease.

Bildgebende Verfahren bei Riesenzellarteriitis (M. Horton)

This review article highlights several diagnostic imaging modalities in giant cell arteritis. Color-coded Duplex sonography is a relatively cost-efficient but strongly observer-dependent imaging modality. It may be difficult to distinguish inflammatory from atherosclerotic mural changes. Positron emission tomography with (18)F-fluoro-2-deoxy-D-glucose is very sensitive in detecting extracranial involvement of large vessel vasculitis. However, it provides no information on inflammatory changes of the superficial cranial arteries. High-resolution MRI is a new observer-independent method that allows visualizing and assessing the superficial cranial arteries in high detail. Extracranial large artery involvement can be evaluated during the same investigation. At present, only single-center experiences with this promising but rather complex procedure exist. A comparative multicenter trial is about to be initiated.

High resolution 3 Tesla contrast-enhanced MR angiography of the hands in Raynaud’s disease

Raynaud's disease is associated with disorders in blood circulation of the hands. The gold standard to visualise pathology of digital arteries is catheter angiography. Contrast-enhanced MR angiography (CE MRA) has developed even more as an alternative non-invasive method to digital subtraction angiography, mostly for pelvic or lower limb vessels. We report a case of primary Raynaud's disease with high-grade stenosis and an occlusion of the digital arteries. This case illustrates the benefit and efficiency of CE MRA at high fields in depicting location and extension of peripheral arterial alterations.

Whole-body MRI in comparison to skeletal scintigraphy in detection of skeletal metastases in patients with solid tumors

AIM

To evaluate the diagnostic value of whole-body magnetic resonance imaging (MRI) and skeletal scintigraphy in the detection of skeletal metastases in patients with solid tumors.

MATERIALS AND METHODS

One hundred and twenty-nine tumor patients were examined with whole-body MRI using coronal TIRM sequences for the different anatomical regions. Skeletal scintigraphy was performed with 99mTc-DPD.

RESULTS

In 105/129 (81%) patients, the whole-body MRI and skeletal scintigraphy findings were concordant. In 56/129 (43%) patients, both imaging modalities excluded skeletal metastases. In 49/129 (38%) patients, whole-body MRI and skeletal scintigraphy revealed metastases, however whole-body MRI demonstrated more extensive disease in 22/49 (45%) cases. In 6/49 (12%) cases, skeletal scintigraphy was superior to whole-body MRI in detecting more skeletal metastases. In 24/129 (19%) cases, the imaging findings were discordant. In 15 cases, skeletal scintigraphy was negative, whereas whole-body MRI revealed skeletal metastases. In 9 cases, skeletal scintigraphy was positive, whereas whole-body MRI failed to detect these metastases. In 77/129 (60%) patients, whole-body MRI revealed additional tumor-related findings.

CONCLUSION

Whole-body MRI, as a new staging method, is superior to skeletal scintigraphy with respect to the detection of skeletal metastases and the extent of metastastic disease. Furthermore, whole-body MRI yields additional tumor-related findings. Therefore, whole-body MRI should be performed as an alternative to skeletal scintigraphy for the assessment of skeletal metastases.

Experimental autologous osteochondral plug transfer in the treatment of focal chondral defects: magnetic resonance imaging signs of technical success in sheep

PURPOSE

To describe the magnetic resonance imaging (MRI) signs of technically successful osteochondral plug transfer and to correlate the findings with histology using the Mankin score.

MATERIAL AND METHODS

The study was done in a prospective animal experiment: 11 adult black-head sheep underwent surgical treatment with osteochondral plug transfer of a knee joint. The animals were killed 6 months later and MRI of the joints was done immediately. MRI was applied with a 1.5T MR scanner using a spin-echo (SE) T1-weighted, turbo spin-echo (TSE) T2-weighted with spectral fat suppression and a fat-suppressed 3D-spoiled gradient echo (GRE) sequence (manufacturer's acronym: FLASH) (TR 50.0 ms, TE 11.0 ms, flip 35 degrees). After MRI, all knee joints were dissected and a biopsy of the plug and the adjacent cartilage was taken. Classification of the cartilage biopsies was carried out in accordance with a modified Mankin score.

RESULTS

Cartilage repairs with a hypointense cartilage signal in the FLASH 3D sequence were correlated with poor histological results (lower Mankin score). Histologically, the regions of cartilage with a hypointense signal showed a fibrocartilage-like repair tissue. Hyaline cartilage with well-defined layers had the same signal intensity in the FLASH sequence relative to adjacent hyaline cartilage. There were two plugs with a surface defect, graded as Outerbridge grade 1 in MRI and histology. Both had a poor outcome in the histologic Mankin score. Grade 2-4 lesions were not observed in the MRI study nor in the histologic study.

CONCLUSION

MRI is a useful non-invasive tool for evaluating the morphologic status of osteochondral plug transfers. A good postoperative result of the cartilage repair was found histologically if an isointense cartilage signal of the graft was documented in the FLASH 3D sequence, and the graft had good congruity with the articular surface without defects.

Diagnostic accuracy of MRI for preoperative staging of pancreatic carcinoma: tendency for understaging

OBJECTIVE

To evaluate the diagnostic accuracy of magnetic resonance imaging (MRI) for preoperative staging in pancreatic carcinoma.

MATERIALS AND METHODS

MRI investigations, including MR-angio and MR-cholangiopancreatography (MRCP) of 19 patients who underwent surgery for pancreatic carcinoma were retrospectively evaluated by two radiologists. The size, localization of the tumor and possible infiltration of neighboring organs, as well as the presence of enlarged lymph nodes, were determined to define a preoperative, radiological TN stage. Lymph node metastasis was defined as peripancreatic lymphoma greater than 10 mm. Our findings were correlated to postoperative diagnosis.

RESULTS

The T-stage was correctly evaluated in 52.6% of the cases (10/19). Understaging took place in 31.6% (6/19) and overstaging in 15.8% (3/19). In three cases of understaging, a micro-infiltration of the peripancreatic tissue was not visible in MRI. Pathologically enlarged lymph nodes were correctly found in 63.2% of the cases (12/19). Overstaging took place in 21.1% of the cases (4/19) and understaging in 15.8% (3/19).

CONCLUSION

MRl for preoperative staging of pancreatic carcinoma showed a tendency to understage tumor size in this study population. Especially in cases of small tumor size, micro-infiltration of peripancreatic tissue or the common bile duct may not be detected by MRI. Concerning N-stage, the 95% confidence interval reveals a distribution of over- and understaged.

Imaging of pheochromocytoma and paraganglioma

Paragangliomas are tumours that arise within the sympathetic nervous system originating from the neural crest. These tumours can be found anywhere from the neck to the pelvis in locations of sympathetic ganglions. Although in the majority of paragangliomas the diagnosis is based on measuring catecholamines and metabolites in plasma or urine, imaging plays an important preoperative role. Today, there are several morphological and radionuclide imaging methods available that predict tumour localisation and tumour extent and give anatomic information to the surgeon. MRI is the morphological imaging modality of choice in localising pheochromocytomas and extra-adrenal paragangliomas. It provides excellent anatomic detail and has the advantage of lacking ionising radiation. The overall accuracy of computed tomography (CT) in detecting primary adrenal pheochromocytomas is very high, but CT lacks in specificity as difficulties may occur in distinguishing between paragangliomas and other tumour entities. The major advantages of radionuclide imaging are very high specificity and routinely performed whole-body scanning. Furthermore, metabolic imaging is not influenced by artifacts like scar tissue or metallic clips in post-surgical follow-up. Currently, a reported specificity of 99% and a cumulative sensitivity of about 90% in paragangliomas make (123)I-MIBG the most important nuclear imaging method. However, (18)F-DOPA-PET seems to be a very promising procedure which offers higher accuracy. The higher spatial resolution of PET-scanners enables the detection of small lesions not visualised with (123)I-MIBG. Both use of radiolabelled somatostatin analogue like (111)In-pentetreotide and (18)F-FDG is limited due to low specificity of the tracers and should be restricted to MIBG- and F-DOPA-negative cases.

Assessment of the cranial involvement pattern of giant cell arteritis with 3T magnetic resonance imaging

OBJECTIVE

To noninvasively determine the involvement pattern of the cranial arteries in giant cell arteritis (GCA), with high-resolution magnetic resonance imaging (MRI).

METHODS

The superficial cranial arteries of 21 patients with suspected GCA were examined using a 3T high-field MRI scanner. Postcontrast T1-weighted spin-echo images were acquired with submillimeter spatial resolution, to assess mural thickness and lumen diameter of the major cranial arteries on both sides of the head. In all cases, MRI results were compared with findings of clinical examination and laboratory tests. In addition, temporal artery biopsy specimens from 10 patients were examined by histology.

RESULTS

MRI sharply revealed all of the major superficial cranial arteries, allowing for an evaluation of their lumen and vessel wall. Nine of the 21 patients were diagnosed as having GCA according to the criteria of the American College of Rheumatology. In all of these patients with clinically diagnosed GCA, multiple cranial arteries showed signs of inflammation on MRI. In 1 patient, the occipital arteries were inflamed, while the temporal arteries were spared.

CONCLUSION

Postcontrast high-resolution MRI visualizes the major cranial arteries on both sides of the head within a single examination. The cranial involvement pattern in GCA can be assessed precisely and noninvasively. In the majority of GCA patients, several cranial arteries were affected simultaneously, with a predominance of involvement of the frontal branch of the superficial temporal artery. Inflammation of the occipital arteries, with sparing of the temporal arteries, was also encountered.

Integrated head-thoracic vascular MRI at 3 T: Assessment of cranial, cervical and thoracic involvement of giant cell arteritis

Recently, high-resolution contrast-enhanced MRI has proven to be feasible for noninvasive diagnosis of giant cell arteritis in the cranium. In such examinations, thickening of the vessel wall and/or increased contrast enhancement demonstrate mural inflammation. Typically, the superficial cranial arteries with predominance of the superficial temporal artery are affected by the disease. However, giant cell arteritis can also involve other parts of the vascular system and an examination with extended coverage, including head, neck, and thorax would be advantageous. In this study, a novel approach for integrated head-thoracic vascular MRI at 3 T is presented. Combining first-pass imaging of a single-dose contrast agent with post-contrast imaging permits the assessment of both thoracic aortic geometry and wall, in addition to high-resolution head imaging needed for the analysis of the small superficial cranial arteries. Results from a patient feasibility study are presented and confirm that the protocol can successfully be completed in less than 40 min.

High grade cardiac lymphoma vitality monitoring by gadolinium-enhanced magnetic resonance imaging (MRI)

Primary cardiac lymphoma (PCL) is a rare disorder with a poor prognosis and response monitoring is often difficult. Delay in the diagnosis and infiltration of cardiac structures contribute to the unfavorable prognosis. We report on a 76-year-old woman who was diagnosed as having an immunoblastic B-cell PCL according to a histology attained by catheter-guided biopsy. Systemic chemotherapy with six cycles of CHOP (Cyclophosphamide, Doxorubicine, Vincristine = Oncovine, Prednisone), combined with the monoclonal anti-CD20 antibody Rituximab induced only a partial remission, based solely on monitoring of tumor size. However, cardiac gadolinium-enhanced magnetic resonance imaging (CMR) disclosed a reduced lymphoma perfusion and, therefore, indicated decreased tumor vitality. Nine months after the final treatment, the cardiac tumor further decreased to 10% of the initial size, and the patient is in sustained remission as monitored by CMR and validated by florine-18 fluorodeoxyglucose positron emission tomography (PET). Determination of PCL perfusion was, in our case, beneficial for clinical decision making on additional therapy.