Markus Uhl

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 rheumatologists 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.

Whole-body MRI in the detection of bone marrow infiltration in patients with plasma cell neoplasms in comparison to the radiological skeletal survey

To compare the diagnostic value of whole-body MRI versus radiological skeletal survey (RSS) in staging patients with plasma cell neoplasms (PCN) and to evaluate the possible therapeutic impact of the replacement of RSS by whole-body MRI. Fifty-four patients with PCN [multiple myeloma (MM), n=47; monoclonal gammopathy of unknown significance (MGUS), n=7] were studied by whole-body MRI and RSS in a monocenter prospective analysis from August 2002 to May 2004. The MRIs were performed using a rolling table platform “AngioSURF” for unlimited field of view with a 1.5-T system (Magnetom Sonata/Maestro Class, Siemens Medical Solutions, Erlangen, Germany). A coronal STIR sequence (TR5500-4230/TE102-94/TI160) was used for imaging of the different body regions, including the head, neck, thorax, abdomen, pelvis and upper and lower extremities. The RSS consisted of eight different projections of the axial and appendicular skeleton. In 41/54 (74%) patients, the results of the whole-body MRI and RSS were concordant. In 11/54 (20%) patients, both imaging techniques were negative. Bone involvement was observed in 30/54 (55%) patients; however, whole-body MRI revealed this more extensively than the RSS in 27/30 (90%) patients with concordant positive imaging findings. In 3/30 (10%) patients, both imaging techniques demonstrated a similar extent of bone marrow infiltration. In 10/54 (19%) patients, the whole-body MRI was superior to RSS in detecting bone marrow infiltration, whereas the RSS was negative. In 3/54 (6%) patients, the RSS was proven to be false positive by the clinical course, whereas the whole-body MRI was truly negative. Whole-body MRI is a fast and highly effective method for staging PCN patients by the use of a rolling table platform. Moreover, it is more sensitive and specific than RSS and reveals bone marrow infiltration and extensive disease more reliably. Therefore, whole-body MRI should be performed as an additional method of exactly staging PCN patients and - with more data in the field - may even prove to be an alternate and more sensitive staging procedure than RSS in PCN patients.

MR imaging of the carpal tunnel

OBJECTIVE Investigations were conducted regarding changes of carpal tunnel shape during wrist motion and the variations of space for the median nerve as well as the preoperative signs of carpal tunnel syndrome (CTS) and the postoperative restitution. METHODS Axial MR images (1.0 T) were performed at the level of the distal radioulnar joint, pisiforme bone and hook of hamate level of 20 wrists of patients with clinical symptoms of CTS and further 20 wrists of volunteers. This was conducted with the wrist in neutral position, 45 degrees extension and 45 degrees flexion. T2-weighted signal intensity of the median nerve were measured in 18 patients pre- and postoperatively. RESULTS The increase of the cross-sectional area of the median nerve at the pisiform level and the flattening of the median nerve at the hook of hamate level as well as the volar bowing of the flexor retinaculum at the pisiform and hook of hamate level were significantly greater in patients with CTS than in those with normal wrists (P < 0.05-0.001). In postoperative follow-up studies the distal flattening of the median nerve recovered in 94%. The signal intensity of the median nerve on T2-weighted images decreased in 67%. CONCLUSIONS Flexion at the pisiform and hamate level as well as extension at the pisiform level narrows the space available for the median nerve potential leading to compression of the median nerve. MR imaging is accurate and reliable for diagnosis and postoperative follow-up of CTS.

Long-term Outcomes After First-Generation Autologous Chondrocyte Implantation for Cartilage Defects of the Knee

Background: Autologous chondrocyte implantation (ACI) represents an established surgical therapy for large cartilage defects of the knee joint. Although various studies report satisfying midterm results, little is known about long-term outcomes. Purpose: To evaluate long-term clinical and magnetic resonance imaging (MRI) outcomes after ACI. Study Design: Case series; Level of evidence, 4. Methods: Between January 1997 and June 2001, a total of 86 patients were treated with ACI for isolated cartilage defects of the knee. The mean patient age at the time of surgery was 33.3 ± 10.2 years, and the mean defect size was 6.5 ± 4.0 cm2. Thirty-four defects were located on the medial femoral condyle and 13 on the lateral femoral condyle, while 6 patients were treated for cartilage defects of the trochlear groove and 17 for patellar lesions. At a mean follow-up of 10.9 ± 1.1 years, 70 patients (follow-up rate, 82%) treated for 82 full-thickness cartilage defects of the knee were available for an evaluation of knee function using standard instruments, while 59 of these patients were additionally evaluated by 1.5-T MRI to quantify the magnetic resonance observation of cartilage repair tissue (MOCART) score. Clinical function at follow-up was assessed by means of the Lysholm score, the International Knee Documentation Committee (IKDC) score, and the Knee injury and Osteoarthritis Outcome Score (KOOS). Patient activity was assessed by the Tegner score. In addition, pain on a visual analog scale (VAS) and patient satisfaction were evaluated separately. Results: At follow-up, 77% reported being “satisfied” or “very satisfied.” The mean IKDC score at follow-up was 74.0 ± 17.3. The mean Lysholm score improved from 42.0 ± 22.5 before surgery to 71.0 ± 17.4 at follow-up (P < .01). The mean pain score on the VAS decreased from 7.2 ± 1.9 preoperatively to 2.1 ± 2.1 postoperatively. The mean MOCART score was 44.9 ± 23.6. Defect-associated bone marrow edema was found in 78% of the cases. Nevertheless, no correlation between the MOCART score and clinical outcome (IKDC score) could be found (Pearson coefficient, r = 0.173). Conclusion: First-generation ACI leads to satisfying clinical results in terms of patient satisfaction, reduction of pain, and improvement in knee function. Nevertheless, full restoration of knee function cannot be achieved. Although MRI reveals lesions in the majority of the cases and the overall MOCART score seems moderate, this could not be correlated with long-term clinical outcomes.

Cystic medial degeneration of the aorta is associated with p53 accumulation, Bax upregulation, apoptotic cell death, and cell proliferation

OBJECTIVE To address a potential role for p53, Bcl2 associated protein X (Bax), and apoptosis in the processes associated with cell turnover during cystic medial degeneration (CMD) of the aorta. METHODS Histochemical, immunohistochemical, biochemical, and morphometric methods were used to assess the presence and distribution of p53 immunoreactivity (p53-IR) and Bax immunoreactivity (Bax-IR), as well as the presence of apoptosis and tissue repair processes. RESULTS Immunohistochemical staining disclosed evidence for p53-IR in all specimens in 26.1 (11.5)% of vascular smooth muscle cells (VSMCs) (controls 0.8 (1.3)%; p < 0.001). Bax-IR was present in all specimens in 10 (5.4)% of medial cells (controls 0.3 (0.5)%; p < 0.001). Medial VSMCs (α-actin positive) with cytoplasmic staining for an apoptosis specific protein (c-jun/ASP) were present in 20/20 specimens (0.7 (0.6)% of VSMCs, controls 0%, p < 0.001), whereas terminal deoxynucleotidyl transferase mediated dUTP-biotin nick end labeling (TUNEL) positive VSMCs were present in 17/20 specimens (1 (1.5)% of VSMCs, controls 0%, p < 0.001). The presence of apoptosis was confirmed by electron microscopy and the demonstration of oligonucleosomal DNA fragments after agarose gel electrophoresis. As shown by double labeling and investigation of serial sections, p53-IR, Bax-IR, c-jun/ASP-IR, and positive TUNEL labeling localised to the same compartments of the aortic media, raising a possible role for p53 and Bax in the triggering of apoptosis of VSMC during CMD. MIB1/Ki-67 positive medial VSMCs (α-actin positive) and mesenchymal cells (vimentin positive) were present in all specimens (2.5 (2.8)% of medial cells; controls 0.3 (0.9)%, p < 0.001) mainly in the region around the vasa vasorum, indicating that cell regeneration during CMD may originate mainly from the mesenchyme surrounding the vasa vasorum. CONCLUSION This study shows that the formal pathogenesis of CMD is characterised by p53 accumulation, Bax upregulation, cell death by apoptosis, and cell regeneration. Nevertheless, the precise stimuli of p53 activation and Bax upregulation as well as the role of p53 and apoptosis in the dissection process itself remain elusive.

Articular cartilage degeneration after acute subchondral bone damage : An experimental study in dogs with histopathological grading

Background Subchondral fracture patterns and bone bruises have been described and some clinical studies have shown alterations in the initially healthy cartilage after such lesions. Methods and results After having performed cadaver studies, we created an animal model to produce pure subchondral damage without affecting the articular cartilage, under MRI control. We used 12 beagle dogs. For quantification of different degrees of staining, we used a grading of the sections by means of the HHGS (Histological-Histochemical Grading System) or Mankin score. Results In all cases, FLASH 3D sequences revealed intact cartilage in MRI after impact. The best detection of subchondral fractures was achieved in fat-suppressed TIRM sequences. Image analysis based on the HHGS showed changes in 10 of 12 samples, with a high degree of significance 6 months after the initial trauma. Correlation analysis showed loss of the physiological distribution of proteoglycans and glycoproteins in the different zones of articular cartilage. Subcategories “Structure”, “Cells” and “Safranin-O Staining” also showed high significance, and the category “Tidemark Integrity” showed a tendency. Interpretation Our findings indicate that acute subchondral fractures are a predictor of degenerative changes within 6 months. Modifications and supplements to rehabilitation might be needed in cases with accompanying subchondral lesions, e.g. in ACL tears.

Human articular cartilage: in vitro correlation of MRI and histologic findings

Abstract. The aim of our study was to correlate MRI with histologic findings in normal and degenerative cartilage. Twenty-two human knees derived from patients undergoing amputation were examined with 1.0- and 1.5-T MR imaging units. Firstly, we optimized two fat-suppressed 3D gradient-echo sequences. In this pilot study two knees were examined with fast imaging with steady precession (FISP) sequences and fast low-angle shot (FLASH, SPGR) sequence by varying the flip angles (40, 60, 90 °) and combining each flip angle with different echo time (7, 10 or 11, 20 ms). We chose the sequences with the best visual contrast between the cartilage layers and the best measured contrast-to-noise ratio between cartilage and bone marrow. Therefore, we used a 3D FLASH fat-saturated sequence (TR/TE/flip angle = 50/11 ms/40 °) and a 3D FISP fat-saturated sequence (TR/TE/flip angle = 40/10 ms/40 °) for cartilage imaging in 22 human knees. The images were obtained at various angles of the patellar cartilage in relation to the main magnetic field (0, 55, 90 °). The MR appearances were classified into five categories: normal, intracartilaginous signal changes, diffuse thinning (cartilage thickness < 3 mm), superficial erosions, and cartilage ulcers. After imaging, the knees were examined macroscopically and photographed. In addition, we performed histologic studies using light microscopy with several different stainings, polarization, and dark field microscopy as well as electron microscopy. The structural characteristics with the cartilage lesions were correlated with the MR findings. We identified a hyperintense superficial zone in the MR image which did not correlate to the histologically identifiable superficial zone. The second lamina was hypointense on MRI and correlated to the bulk of the radial zone. The third (or deep) cartilage lamina in the MR image seemed to represent the combination of the lowest portion of the radial zone and the calcified cartilage. The width of the hypointense second zone correlated weakly to the accumulation of proteoglycans in the radial zone. The trilaminar MRI appearance of the cartilage was only visible when the cartilage was thicker than 2 mm. In cartilage degeneration, we found either a diffuse thinning of all layers or circumscribed lesions (“cartilage ulcer”) of these cartilage layers in the MR images. Early cartilage degeneration was indicated by a signal loss in the superficial zone, correlating to the histologically proven damage of proteoglycans in the transitional and radial zone along with destruction of the superficial zone. We found a strong effect of cartilage rotation in the main magnetic field, too. A rotation of the cartilage structures caused considerable variation in the signal intensity of the second lamina. Cartilage segments in a 55 °angle to the magnetic main field had a homogeneous appearance, not a trilaminar appearance. The signal behavior of hyaline articular cartilage does not reflect the laminar histologic structure. Osteoarthrosis and cartilage degeneration are visible on MR images as intracartilaginous signal changes, superficial erosions, diffuse cartilage thinning, and cartilage ulceration.

Sinonasal computed tomography in patients with Wegener's granulomatosis.

The goal of this study was to describe pathologies of sinonasal CT in patients with Wegeners granulomatosis. Between 1993 and 2004, sinonasal CT was performed in 28 patients (15 male, 13 female) with Wegeners granulomatosis. The following imaging findings were assessed on the CT scans: mucosal thickening, subtotal opacification, air-fluid level, bony destruction, sclerosing osteitis, bony thickening, orbital mass, and saddle nose deformity. Of the 28 patients, 61% showed mucosal thickening in the nasal cavity and 75% in the paranasal sinuses. A subtotal opacification of the paranasal sinuses was detected in 25%, and of the mastoid cells in 7% of patients. Fifty-seven percent of patients had bony destruction of the nasal cavity, and 54% of the paranasal sinuses. CT revealed sclerosing osteitis of the paranasal sinuses in 21%, and of the mastoid cells in 18% of patients. Bony thickening of the paranasal sinuses was detected in 18%, and of the mastoid cells in 14% of patients. With respect to all imaging findings, the maxillary sinuses were the most frequently affected paranasal sinuses. The authors conclude that the following sinonasal CT findings are observed in patients with Wegeners granulomatosis: (1) bony destruction, mainly of the nasal cavity, maxillary sinuses, and mastoid cells; (2) sclerosing osteitis, mainly of the maxillary sinuses and mastoid cells; (3) bony thickening, mainly of the maxillary sinuses and mastoid cells; and (4) mucosal thickening, mainly of the maxillary sinuses. These findings are, however, nonspecific and should be combined with other clinicopathologic and laboratory studies to confirm the diagnosis of Wegeners granulomatosis.

High resolution 3T MRI for the assessment of cervical and superficial cranial arteries in giant cell arteritis

A new high‐resolution MR protocol for the combined assessment of neurovascular arterial anatomy and subsequent evaluation of inflammatory disease in cranial vessels walls has been investigated. First‐pass contrast‐enhanced MR angiography (CE‐MRA) in combination with parallel imaging at high field permits the depiction of the neurovascular geometry with large coverage, including the aortic arch, supraaortic vessels, and almost the entire head, with high, submillimeter detail. Utilizing the remaining contrast agent, postcontrast T1‐weighted turbo spin‐echo (TSE) imaging was used to generate late enhancement images of the vessel walls to assess the morphology and potential inflammatory changes in cranial arteries with high in‐plane (195 × 260 μm2) spatial resolution. As a result, a combined analysis of neurovascular arterial anatomy as well as cranial vessel wall inflammations could be achieved in less than 45 minutes in all studies. The feasibility and clinical value for the diagnosis of rheumatologic diseases and simultaneous arteriosclerotic involvement was demonstrated in seven patients with suspected giant cell arteritis (GCA). Excellent CE‐MRA image quality could be achieved and even vascular geometry of small superficial cranial arteries could be successfully visualized using single dose (0.1 mmol/kg) contrast agent administration and a dedicated phased‐array head and neck coil at 3T. J. Magn. Reson. Imaging 2006.

Management of delayed visceral arterial bleeding after pancreatic head resection.

Despite low mortality, postoperative complications are still relatively frequent after pancreatic head resection. The occurrence of delayed visceral arterial bleeding from erosions or pseudoaneurysms of branches of the celiac trunk or from the stump of the gastroduodenal artery is a rare but life-threatening complication and is probably underreported in the literature. During a 10-year period, we diagnosed and treated 12 patients (three referred from other hospitals) with severe visceral arterial bleeding, presenting 7 to 85 days after pancreatic head resection. Clinical presentation was gastrointestinal bleeding (seven patients) or abdominal bleeding (five patients). The bleeding source was identified by angiography in 10 of the 12 cases. Definitive bleeding control was achieved by angiography in six of the 12 patients (stent 2, coiling 4), or by surgery in five patients. None of the six patients with successful angiographic intervention required further surgery for bleeding control. One patient died due to hemorrhage before bleeding was controlled. Median transfusion requirement was 12.5 (range 3–37) units. Of five patients with interventional or surgical occlusion of the common hepatic artery, three developed hepatic abscesses and two had complications of the hepaticojejunostomy. One of those five patients died four months after definitive bleeding control because of recurrent hepatic abscesses. All other patients eventually recovered completely. We conclude that delayed arterial bleeding from visceral arteries is a rare but life-threatening complication after pancreatic head resection. Angiographic stenting with preservation of hepatic blood flow, if technically possible, represents the best treatment option.