Relevant imaging findings of cerebral aspergillosis on MRI: a retrospective case-based study in immunocompromised patients.

The aim of the study was to assess neuroimaging patterns of cerebral aspergillosis with magnetic resonance imaging (1.5 T). The clinical and imaging data of nine patients were reviewed. Patients were included in the study if the diagnosis of aspergillosis was confirmed by either biopsy, autopsy, aspergillus antigen determination and/or neuroradiological and clinical response to specific treatment. Four patients had single or multiple abscesses presenting as ring-enhancing lesions on T1-weighted images, hypointensity of the ring on T2-weighted MR images and low to high signal intensity on diffusion-weighted imaging. Four patients had single or multiple infarctions affecting all compartments of the brain with hyperintensities on T2-weighted images in three of four patients, irregular parenchymal contrast enhancement in all patients and hemorrhagic transformation of the infarcted parenchyma in one patient. Diffusion-weighted images were positive in all ischemic areas. One patient with paranasal sinusitis developed a mycotic aneurysm of the internal carotid artery. Cerebral aspergillosis presents three principal neuroimaging findings: areas consistent with infarction; ring lesions consistent with abscess formation following infarction; and dural or vascular infiltration originating from paranasal sinusitis or orbital infiltration. Recognition of these patterns in cerebral aspergillosis may lead to more timely and effective diagnosis and treatment.

Comparison of contrast-enhanced power Doppler ultrasound (Levovist) and computed tomography in alveolar echinococcosis.

BACKGROUND: To date, no study has compared unenhanced and contrast-enhanced (Levovist) power Doppler ultrasound with three-phase helical computed tomography (CT) for the analysis of the vascularization of hepatic lesions in patients who have alveolar echinococcosis. METHODS: Fifteen patients (11 female and four male; average age, 45.8 years) with confirmed Echinococcus multilocularis infection underwent unenhanced and contrast-enhanced (Levovist) power Doppler ultrasound (2- to 5-MHz transducer head) and three-phase helical CT. The largest identified lesion in each patient was studied. RESULTS: CT visualized vascularization peripheral or central to the largest echinococcal lesions in 11 of 15 patients. Vascularization in the area of the echinococcal lesions was not visualized by unenhanced or contrast-enhanced power Doppler ultrasound in any of the 15 patients studied. CONCLUSION: Three-phase helical CT visualizes the vascularization associated with Echinococcus multilocularis lesions in the liver. Neither unenhanced nor contrast-enhanced ultrasound in power mode is suitable for this application.

[Non-invasive, multi detector row (MDR) CT based computational fluid dynamics (CFD) analysis of hemodynamics in infrarenal abdominal aortic aneurysm (AAA) before and after endovascular repair]. / Blutflusssimulation mittels Computational-Fluid-Dynamics an aus CT-Daten rekonstruierten Aortenaneurysmata vor und nach Stent-Graft Implantation.

PURPOSE: Simulation, description and analysis of dynamic pressure in infrarenal abdominal aortic aneurysms (AAA) before and after endovascular repair. MATERIALS AND METHODS: During March 1996 and May 2001, 13 patients with AAA underwent endovascular treatment. The MDR-CT scans of these patients were used for the non-invasive analysis of the hemodynamics in the aorta with CFD software before and after endovascular repair. One pre-interventional and three post-interventional CT scans were analyzed for each patient. RESULTS: Compared to the pre-interventional simulation, endovascular treatment led to an average dynamic pressure decrease of 1057 Pa in 10 of 13 patients. During the subsequent course, the median of the dynamic pressure decreased in 8 of 13 patients. Vulnerable regions initially identified as high-pressure regions, like the docking area or the second stent limb, adapted to the pressure in the surrounding tissue in the course of time. CONCLUSION: CFD-based blood flow simulation offers the opportunity to analyze dynamic pressure in AAA before and after endovascular repair and allows a prognostic statement as to the possible homogenization of the pressure in abdominal stent-grafts.

[Quantifying the inflammatory activity in Crohn's disease using CE dynamic MRI]. / Kontrastmittel-gestützte dynamische MRT des Dünndarms zur Beurteilung der lokalen Entzündungsaktivität bei Morbus Crohn.

PURPOSE: Evaluation of dynamic contrast enhanced MRI in patients with Crohn's disease to assess local inflammatory activity. MATERIAL AND METHODS: Prospective study of 13 patients with histologically proven Crohn's disease. Axial and coronal slices were acquired by a 1.5 T MR (Magnetom Vision, Siemens, Germany): T1 flash 2 D (TR 72.5 ms, TE 4.1 ms), T2 (TR 2730 ms, TE 138 ms), turbo-flash sequences T1 (TR 94.2 ms, TE 4.1 ms) post contrast media fat saturated (Magnevist, 0.2 ml/kg, flow 4 ml/s). In area of maximal thickening of terminal ileal wall, axial dynamic T1 sequences (TR 11 ms, TE 4.2 ms) were acquired every 1.5 s post contrast media application for a total duration of 1 min. Contrast uptake was subjectively measured by semiquantitative score and computed assisted ROI evaluation. MR parameters were correlated with CDAI (Crohn's disease activity index) and SAI (severe activity index). RESULTS: Contrast uptake in the intestinal wall occurred after 18.5 s (range: 3.0 - 28.0), contrast upslope until plateau phase lasted for 16.1 s (range: 8.0 - 50.0). Maximum contrast enhancement into the bowel wall was 266 % (105 - 450 %) of baseline. After maximum contrast uptake, we observed a plateau phase in all cases for the total duration of measurement. A significant correlation existed for maximum contrast uptake to CDAI (r = 0.591; p = 0.033), for beginning of contrast upslope to the time until plateau phase (r = 0.822; p = 0.001), and for the time until plateau phase to CDAI (r = 0.562; p = 0.046). CDAI was on average 108, median 106; SAI was on average 114, median 115. SAI correlated significantly to CDAI (r = 0.874). Maximum contrast uptake, beginning of contrast upslope, and time until plateau phase were independent to creeping fat, local lymphadenitis, laboratory parameters, temperature, body mass index, heart frequency and systolic blood pressure. CONCLUSION: Dynamic MRI enables to quantify local inflammatory activity of bowel wall in patients with Crohn's disease. Larger studies are necessary to establish this method in clinical routine.

[Diffuse pulmonary ossifications with mortal consequences. A case report]. / Diffuse pulmonale Ossifikation mit KrankheitswertA case report.

Dendriform pulmonary ossification (DPO) represents a relatively frequent form of diffuse pulmonary and mostly clinically inapparent bone formation of unknown etiology. An association with other pulmonary diseases, particularly pulmonary interstitial fibrosis, has been suggested. Here we report a female patient with a 15-year history of DPO whereby at the age of 48 an X-ray of the thorax first revealed findings suggestive of pulmonary fibrosis. For 9 years the patient suffered from chronic progressive ventilation disorder and after a further 3 years open lung biopsy revealed DPO in conjunction with interstitial fibrosis. After a history of progressive respiratory failure the patient suddenly died of cardiac arrhythmia along with deteriorated cor pulmonale at the age of 71. Autopsy revealed an almost complete ossification of the lungs with an increasing gradient from apex to base. In contrast to previous reports, the DPO of our patient was life-limiting.

Pre-operative staging of invasive breast cancer with MR mammography and/or PET: boon or bunk?

This study compared pre-operative staging with MR mammography (MRM) and positron emission tomography (PET) in patients with clinically suspected breast cancer according to the Breast Imaging Reporting and Data System, category 5. A total of 43 patients with breast cancer were examined. MRM included both T(2) weighted turbo spin echo sequences and T(1) weighted gradient echo sequences (three-dimensional fast low angle shot) before and after application of gadolinium-DPTA. All patients then underwent examination with a modern full-ring PET scanner following injection of fluorodeoxyglucose. We evaluated the efficacy of these methods in the diagnosis of primary tumour, contralateral carcinomas, bifocal, trifocal or multifocal disease, as well as non-invasive cancer portions and tumour size. Determination of patients' N-status was only attempted using PET. All findings were validated by histological examination. MRM was slightly superior to PET in several areas, such as in the respective methods' sensitivity and specificity. Sensitivities for MRM and PET were: 100% vs 93.0% in diagnosis of the primary tumour; 100% vs 100% in diagnosis of contralateral carcinomas; and 95.2% vs 92.5% in diagnosis of bifocal, trifocal or multifocal disease. Specificities for MRM and PET were: 100% vs 97.5% in diagnosis of contralateral carcinomas; and 96.8% vs 90.3% in diagnosis of bifocal, trifocal or multifocal disease. Non-invasive cancer portions and tumour sizes were equally well determined with both methods. The sensitivity of PET for detection of lymph node involvement was 80% and specificity 95%. MRM and PET were superior to conventional methods in nearly all areas studied; the findings of one or both of the methods impacted positively on patients' surgical treatment in 12.5-15% of cases. Pre-operative MRM and/or PET can have a positive influence on surgical treatment planning. Therefore, it appears useful to perform pre-operative staging with MRM or PET in these patients.

Breast MRI for monitoring response of primary breast cancer to neo-adjuvant chemotherapy.

The objective of the present study was to monitor response to preoperative chemotherapy with breast MRI in patients with large breast cancer. Fifty-eight women in whom core biopsy had confirmed the presence of breast carcinoma underwent breast MRI prior to beginning chemotherapy and before surgical excision. In 24 cases patients underwent one or two additional examinations during chemotherapy to monitor their progress. Breast MRI included both T2-weighted spin-echo sequences and T1-weighted gradient-echo sequences before and 1, 2, 3, and 8 min after bolus injection of gadolinium-DTPA. Tumor size and the dynamic contrast medium uptake patterns of the respective carcinomas were evaluated and compared with the final histology findings. Based on their MR tomographic findings (change in tumor size and intensity of contrast media uptake), patients were assigned to groups with non-response (NR), partial response (PR), and complete response (CR). Based on MR tomographic findings, there were 12 patients in the NR group, 34 in the PR group, and 12 in the CR group. In NR group contrast medium uptake tended to increase or show no more than minimal decrease. Diagnostic accuracy for assigning patients to the NR group was 83.3% and to the PR group 82.4%. In patients whose tumors showed only slight response to chemotherapy, breast MRI proved very reliable in determining the size of the lesions. In patients whose tumors displayed significant response and in the CR group, the size of the residual tumor was underestimated in 8 of 12 cases. In 66.7% of patients in the CR group histology revealed residual tumor masses in areas up to 5 cm in diameter. During chemotherapy, intensity of contrast medium uptake decreased in 88.2% of patients with PR and in all patients with CR. Reliable determination of response was possible within 6 weeks following the initiation of chemotherapy. Breast MRI is suitable as a monitoring method. The determination of residual tumor size is unreliable in carcinomas exhibiting significant response to chemotherapy which may lead to false-negative results. The method may be employed for monitoring response to chemotherapy after 6 weeks.

MRI of the abdomen with positive oral contrast agents for the diagnosis of inflammatory small bowel disease.

Magnetic resonance imaging (MRI) is being used more often in the evaluation of inflammatory bowel diseases. A prerequisite for adequate image quality is the oral application of contrast medium, which can be administered with different modalities. Positive and negative oral contrast media can be used; in terms of diagnostic efficacy, there appears to be no relevant differences between them. Sequences usually are acquired using breath-hold or respiration-triggered protocols. The underlying principle is visualization of circumscribed thickening of the intestinal wall, which shows a pathologic pattern of contrast medium uptake. The available data suggest that MRI is equally as effective as enteroclysis in the primary diagnosis of Crohn's disease and actually more sensitive in the detection of extraintestinal manifestations such as fistulae or abscesses. Supporters of the method predict that MRI will replace enteroclysis in the long term.

Prospective evaluation of the clinical value of planar bone scans, SPECT, and (18)F-labeled NaF PET in newly diagnosed lung cancer.

UNLABELLED: Previous studies have shown that vertebral bone metastases (BM) not seen on planar bone scintigraphy (BS) might be present on (18)F-fluoride PET scans or at MRI. Therefore, we evaluated the effect of SPECT or (18)F-labeled NaF PET ((18)F PET) imaging on the management of patients with newly diagnosed lung cancer. METHODS: Fifty-three patients with small cell lung cancer or locally advanced non-small cell lung cancer were prospectively examined with planar BS, SPECT of the vertebral column, and (18)F PET. MRI and all available imaging methods, as well as the clinical course, were used as reference methods. BS with and without SPECT and (18)F PET were compared using a 5-point scale for receiver operating characteristic (ROC) curve analysis. RESULTS: Twelve patients had BM. BS produced 6 false-negatives, SPECT produced 1 false-negative, and (18)F PET produced no false-negatives. The area under the ROC curve was 0.779 for BS, 0.944 for SPECT, and 0.993 for (18)F PET. The areas under the ROC curve of (18)F PET and BS complemented by SPECT were not significantly different, and both tomographic methods were significantly more accurate than planar BS. As a result of SPECT or (18)F PET imaging, clinical management was changed in 5 patients (9%) or 6 patients (11%), respectively. CONCLUSION: As indicated by the area under the ROC curve analysis, (18)F PET is the most accurate whole-body imaging modality for screening for BM. Routinely performed SPECT imaging is practicable, is cost-effective, and improves the accuracy of BS.

Metallic stents in benign biliary strictures: long-term effectiveness and interventional management of stent occlusion.

OBJECTIVE: The objective of our study was to evaluate the long-term effectiveness of metallic stent placement in the treatment of benign biliary strictures and to report our experience with interventional procedures for the management of stent occlusion to achieve secondary patency. CONCLUSION: The clinical course of these patients is compromised by repeated stent occlusions, caused by stone or mucosal hyperplasia. The results of primary stent patency are disappointing with the primary patency rate decreasing from 75% after 12 months to 25% after 36 months. The different interventional procedures used to restore bile flow make an important contribution to the secondary stent patency and provide a satisfactory clinical result in a patient subpopulation in whom stent placement is considered the last resort.

Percutaneous techniques for managing maldeployed or migrated stents.

PURPOSE: To report our experience in the percutaneous management of dislocated endovascular stents. METHODS: During a 6-year period, 28 (2.7%) patients with a maldeployed or migrated endovascular stent (20 Palmaz, 5 Wallstent, 2 Memotherm, and 1 AVE) were recognized among 1021 patients undergoing noncardiac vascular stent procedures. Percutaneous stent management was performed using balloon catheters, gooseneck snares, grasping forceps, or additional stent implantation on the basis of the stent type, degree of expansion, mechanical characteristics, and location of the stent. RESULTS: Three stents that embolized into the pulmonary artery were left in situ, but percutaneous management was successful in 23 (92%) of the remaining 25 dislocated stents (12 venous and 13 arterial stents). Twelve stents were repositioned in an alternate, stable position or the primarily intended location; 4 stents were anchored by a second stent, and 7 stents were removed percutaneously. In the 2 failed cases, the stents were retrieved using a minor surgical procedure. There were 2 minor groin hematomas but no secondary complications during a median follow-up of 26.2 months (range 1-62). CONCLUSIONS: Percutaneous management of migrated or maldeployed endovascular stents is highly effective with few complications. On the basis of our findings, these techniques should be considered the therapy of choice.

Ionic and non-ionic contrast agent-mediated endothelial injury. Quantitative analysis of cell proliferation during endothelial repair.

PURPOSE: To quantitatively evaluate endothelial injury in vivo and to assess the time course of cellular repair after endothelial cell exposure to ionic and non-ionic contrast media. MATERIAL AND METHODS: Local changes at the cellular level following intraaortic injection of 1 ml of the ionic contrast agent ioxithalamate or 1 ml of the non-ionic contrast agent iomeprol, each with an iodine content of 300 mg/ml, were investigated using rat endothelium as an in vivo model. A sorbitol solution iso-osmolar to iomeprol served as control. Quantitative analysis of endothelial changes by autoradiography of 3H-thymidine-labeled endothelial cells was assessed after 3, 5 and 10 days, determining the 3H-thymidine index and the DNA synthesis rate. RESULTS: Ioxithalamate showed a clear harmful effect on the endothelium, with an elevated 3H-thymidine index of 7.68% on day 3 and 6.89% on day 5, versus 2.97% on day 3 and 2.55% on day 5 for iomeprol and 2.29% on day 3 and 1.91% on day 5 for the control. CONCLUSION: Ionic contrast agents lead to reversible transient focal endothelial cell injury. No such side effect was detectable for non-ionic contrast agents.

Percutaneous retrieval of lost or misplaced intravascular objects.

OBJECTIVE: We report on our experience with percutaneous interventional techniques for retrieval of intravascular foreign bodies or repositioning of misplaced endovascular prostheses. MATERIALS AND METHODS: Over a period of 6 years, we attempted percutaneous treatment of intravascular foreign bodies in 45 patients. The 45 foreign objects consisted of 12 endovascular stents, 14 catheter fragments, 11 embolization coils, four guidewire fragments, three vena cava filters, and one cardiac valve fragment. Percutaneous extraction was performed using a combination of multipurpose catheters and nitinol snare loop or grasping forceps. Depending on their composition, misplaced or dislodged intravascular stents were either repositioned or percutaneously removed. RESULTS: Percutaneous intervention was successful in 41 (91.1%) of 45 patients. Of 38 patients on whom we performed percutaneous removal, the procedure was successful in 34 patients (89.5%), including 13 of the 14 patients with catheter fragments, all four of the patients with guidewire fragments, 10 of the 11 patients with misplaced or dislodged embolization coils, four of the five patients with misplaced or dislodged endovascular stents, and all three of the patients with misplaced or dislodged vena cava filters. The procedure was not successful in the one patient with a cardiac valve fragment. All seven of the percutaneous repositioning procedures we performed resulted in the endovascular stent being successfully repositioned in a stable intravascular position. Most of the retrieval procedures (77.7%) were performed using the nitinol snare as the primary instrument. No late complications were registered during the follow-up period, which ranged from 9 to 68 months (mean, 42.4 months overall). CONCLUSION: Percutaneous techniques for the extraction of intravascular foreign objects or for repositioning of dislocated endovascular stents are highly effective with a low rate of complications and should always be the primary method of choice.

Ability of MR cholangiography to reveal stent position and luminal diameter in patients with biliary endoprostheses: in vitro measurements and in vivo results in 30 patients.

OBJECTIVE: Our goal was to evaluate the ability of MR cholangiography to show stent position and luminal diameter in patients with biliary endoprostheses. MATERIALS AND METHODS: Susceptibility artifacts were evaluated in vitro in three different stent systems (cobalt alloy-based, nitinol-based, and polyethylene) using two breath-hold sequences (rapid acquisition with relaxation enhancement, half-Fourier acquisition single-shot turbo spin echo) on a 1.5-T MR imaging system. The size of the stent-related artifact was measured, and the relative stent lumen was calculated. In vivo stent position and patency were determined in 30 patients (10 cobalt alloy-based stents, five nitinol-based stents, and 15 polyethylene stents). RESULTS: In vitro, the susceptibility artifact of the cobalt stent caused complete obliteration of the stent lumen. The relative stent lumens of the nitinol-based and polyethylene stents were 38-50% and 67-100%, respectively. In vivo, all stents were patent at the time of imaging. The position of the cobalt alloy-based stent could be determined in nine of 10 patients, but stent patency could not be evaluated. Stent position of nitinol stents could not be adequately evaluated in any of the five patients, and internal stent diameter could be visualized in only one patient. In nine of 15 patients, the fluid column within the implanted polyethylene stent was seen on MR cholangiography. CONCLUSION: The internal stent lumen could be visualized in most patients with an indwelling polyethylene stent, but not in patients with cobalt alloy- or nitinol-based stents.

Endovascular interventions on persistent sciatic arteries.

PURPOSE: To report our experience with interventional procedures used to treat complete and incomplete persistent sciatic arteries (PSA). CASE REPORTS: Three female patients with PSAs displayed varying symptoms referable to this rare anatomical variant. In the first woman, a 1-year history of intermittent lower limb ischemia and an acute event prompted angiography, which demonstrated proximal occlusion of 2 crural vessels and a partially thrombosed sciatic artery aneurysm. To prevent further embolism, the aneurysm was excluded with a stent-graft. Endograft patency and aneurysm exclusion have been maintained up to 22 months. In a 41-year-old diabetic with chronic limb ischemia and digital gangrene, a flow-limiting stenosis of the sciatic artery was stented, restoring adequate pedal perfusion. The stent remained patent at the 18-month follow-up. The third patient suffered from a tumor-related pelvic hemorrhage originating from retrograde perfusion through the PSA, which had been ligated during previous surgery. Attempted embolization via a collateral connection between the incomplete PSA and the popliteal artery failed, and the patient died. CONCLUSIONS: Vasculopathies involving the sciatic artery are uncommon but may be amenable to interventional techniques, such as coil embolization and stent implantation. PSA aneurysm exclusion with a stent-graft may represent a new therapeutic alternative to standard surgery that obviates potential sciatic nerve damage, but the durability of the repair remains to be determined.

[Pancreatic interventions: biopsy, drainage, necrosectomy--from the viewpoint of the radiologist]. / Interventionen am Pankreas: Biopsie, Drainage, Nekrosektomie--Sicht des Radiologen.

The following publication is an overview looking at diagnostic and therapeutic possibilities related to interventional procedures for diseases of the pancreas. We emphasize the description of the technique and show meaningful indications and limitations.

[Intraarterial chemotherapy in cases of breast cancer]. / Intraarterielle Chemotherapie beim Mammakarzinom.

A general review of the results and technique of intraarterial chemotherapy in cases of breast cancer is given. The remission rate for untreated primary tumors is nearly 100%, for completely treated local relapses approximately 70%. The complication rate is quite low using an intraarterial well-tolerated cytostatic agent such as mitoxantrone. However, thromboembolism of the vertebral artery facing the internal mammary artery may occur. The indication for intraarterial chemotherapy should always be set by an interdisciplinary board.