Andrea Rieber

Fluorine-18 2-deoxy-2-fluoro-D-glucose PET in the preoperative staging of breast cancer: comparison with the standard staging procedures.

The present study compared the diagnostic accuracy of fluorine-18 2-deoxy-2-fluoro-D-glucose positron emission tomography (FDG-PET) with conventional staging techniques. The differentiation between malignant and benign lesions and the detection of multifocal disease, axillary and internal lymph node involvement, and distant metastases were evaluated. One hundred and seventeen female patients were prospectively examined using FDG-PET and conventional staging methods such as chest X-ray, ultrasonography of the breast and liver, mammography and bone scintigraphy. All patients were examined on a modern full-ring PET scanner. Histopathological analysis of resected specimens was employed as the reference method. The readers of FDG-PET were blinded to the results of the other imaging methods and to the site of the breast tumour. The sensitivity and specificity of FDG-PET in detecting malignant breast lesions were 93% and 75% respectively. FDG-PET was twofold more sensitive (sensitivity 63%, specificity 95%) in detecting multifocal lesions than the combination of mammography and ultrasonography (sensitivity 32%, specificity 93%). Sensitivity and specificity of FDG-PET in detecting axillary lymph node metastases were 79% and 92% (41% and 96% for clinical evaluation). FDG-PET correctly indicated distant metastases in seven patients. False-positive or false-negative findings were not encountered with FDG-PET. Chest X-ray was false-negative in three of five patients with lung metastases. Bone scintigraphy was false-positive in four patients. Three patients were upstaged since FDG-PET detected distant metastases missed with the standard staging procedure. It is concluded that, compared with the imaging methods currently employed for initial staging, FDG-PET is as accurate in interpreting the primary tumour and more accurate in screening for lymph node metastases and distant metastases. Due to a false-negative rate of 20% in detecting axillary lymph node metastases, FDG-PET cannot replace histological evaluation of axillary status.

MRI in the diagnosis of small bowel disease: use of positive and negative oral contrast media in combination with enteroclysis.

Abstract. The aim of the study was to evaluate the additional findings of MRI following small bowel enteroclysis and to compare the efficacy of negative and positive intraluminal contrast agents. Fifty patients with inflammatory or tumorous small bowel disease were investigated by small bowel enteroclysis and consecutive MRI using breathhold protocol (T1-weighted fast low-angle shot, T2-weighted turbo spin echo). Patients were randomly assigned to either receiving a positive oral (Magnevist, Schering, Berlin, Germany) or a negative oral MR contrast media (Abdoscan, Nycomed, Oslo, Norway). The pattern of contrast distribution, the contrast effect, presence of artifacts, as well as bowel wall and extraluminal changes, were determined and compared between the contrast type using Fischers exact test. Sensitivity, specificity, and diagnostic accuracy for MRI and enteroclysis were calculated. Twenty-seven patients had clinically proven Crohns disease and two patients surgically proven small bowel tumours. Magnetic resonance imaging had important additional findings as abscesses and fistulae in 20 patients. Surgically compared sensitivities were 100 and 0 % for MRI and enteroclysis, for the detection of abscesses, and 83.3 and 17 % for the diagnosis of fistulae, respectively. Bowel wall thickening was more reliably detected with use of positive oral contrast media without intravenous enhancement (p < 0.001), whereas postcontrast negative oral contrast media allow for a superior detection (p < 0.001). T2-weighted sequences were necessary with use of negative oral contrast media, because loop abscesses may be masked. Magnetic resonance imaging should be performed in all patients with suspicion of extraintestinal complications, because the complications are more reliably detected by MRI. Negative oral contrast media show advantages with the use of intravenous contrast but can mask loop abscesses using only T1-weighted imaging.

Diagnostic imaging in Crohn's disease: comparison of magnetic resonance imaging and conventional imaging methods.

Abstract Conventional enteroclysis remains the method of choice in the diagnosis of inflammatory small bowel disease. The reported sensitivity rates, however, for the diagnosis of extraintestinal processes, such as fistulae and abscesses, are moderate. Computed tomography (CT) is the method of choice for the diagnosis of extraintestinal complications. The anatomical designation of the affected bowel segment may, however, prove difficult due to axial slices, and the applied radiation dose is high. The use of magnetic resonance imaging (MRI) in the diagnosis of inflammatory small bowel disease is a relatively new indication for the method; prerequisites were the development of breathhold sequences and phased array coils. Optimized magnetic resonance tomographic imaging requires a combined method of enteroclysis and MRI, which guarantees an optimal filling and distension of the small bowel. The high filling volume leads to a secondary paralysis of the small bowel and avoids motion artifacts. In a trial of 84 patients with histological and endoscopic correlation the sensitivity in diagnosing inflammatory bowel disease was 85.4% for enteroclysis and 95.2% for MRI, and the specificity was 76.9% for enteroclysis and 92.6% for MRI. As none of the abscesses was diagnosed with enteroclysis, the sensitivity was 0% for enteroclysis, but 77.8% for MRI. The sensitivity in diagnosing fistulae was 17.7% for enteroclysis and 70.6% for MRI. In summary, MRI can detect the most relevant findings in patients with inflammatory small bowel disease with an accuracy superior to that of enteroclysis.

MRI of histologically confirmed mammary carcinoma : Clinical relevance of diagnostic procedures for detection of multifocal or contralateral secondary carcinoma

PURPOSE MR mammography (MRM) is a sensitive diagnostic method for the detection of mammary carcinomas. The present study evaluates whether MRM can yield additional relevant data in cases of histologically confirmed mammary carcinoma. METHOD Thirty-four patients with histologically confirmed mammary carcinoma were examined at MRM using a T1-weighted GE sequence and a T2-weighted SE sequence. Morphologic criteria and the dynamic contrast medium behavior of the tumors were evaluated. RESULTS MRM showed a 100% sensitivity and diagnostic accuracy in the detection of mammary carcinomas. Additionally, three unexpected contralateral carcinomas were discovered. In 26 patients, there was a multifocal or multicentric tumor process. In 24 patients, peritumoral edema was visualized, which corresponded histologically in 21 patients with lymphangiosis and in 3 with an inflammatory peritumoral reaction. CONCLUSION Because of its high sensitivity in the diagnosis of multifocal disease and of contralateral carcinomas, MRM would seem to represent a useful addition to preoperative diagnostic procedures. The potential benefit to the patient and its cost efficiency, however, remain to be clarified.

Ultrasound and magnetic resonance imaging in Crohn's disease: a comparison

Abstract. The objective of this retrospective study was to compare MRI of the abdomen with ultrasound of the abdomen and gastrointestinal tract in patients with Crohns disease. Forty-six patients were included in the study. We analyzed the localization of Crohns lesions, the number of affected bowel segments, the number of stenoses, and the presence of abscesses, fistulae, and any additional findings. Findings were verified by means of one or more of the following: enteroclysis; surgical findings; and colonoscopy. The results show that MRI is superior to ultrasound in the localization of affected bowel segments (sensitivity: MRI 97.5%; US 76%) and in recognizing fistulae (sensitivity: MRI 87%; US 31%), stenoses (sensitivity: MRI 100%; US 58%) and abscesses (sensitivity: MRI 100%; US 89%). Magnetic resonance imaging of the abdomen should be obtained to clarify discrepant clinical and sonographic findings. In addition, despite its higher cost, MRI of the abdomen is justified in patients in whom Crohns lesions are known or suspected in anatomic areas proximal to the terminal or neoterminal ileum and in cases with suspicion of fistulae and abscesses.

MRI of the breast in the differential diagnosis of mastitis versus inflammatory carcinoma and follow-up.

PURPOSE Our goal was to evaluate the potential of dynamic MRI in differentiating mastitis and inflammatory breast carcinoma. Furthermore, we evaluated the potential of breast MRI to follow up mastitis patients under antibiotic treatment. METHOD Twenty-one cases of dynamic breast MR (11 mastitis, 10 inflammatory carcinomas) were reviewed. All patients had a history consistent with either mastitis or inflammatory breast carcinoma. The final diagnosis was histologically confirmed. RESULTS Ninety percent of the inflammatory carcinomas were found to enhance > 100% in the first minute compared with 55% for mastitis. There is no significant difference between mastitis and inflammatory carcinoma. CONCLUSION While breast MR cannot currently be used definitively to distinguish inflammatory carcinoma from mastitis, the differences in dynamic enhancement may prove to be useful in follow-up of presumed mastitis in problematic cases. If after biopsy the diagnosis remains unclear, breast MR may help to (a) demonstrate the success of the antibiotic treatment and (b) diagnose coexisting or confounding inflammatory carcinoma.

Metallic stents in malignant biliary obstruction

PurposeRetrospective analysis of our results with metallic stent placement for malignant biliary strictures. We sought to determine parameters that influence stent patency.MethodsA total of 95 Wallstents were implanted in 65 patients (38 men, 27 women; mean age, 65.1 years) with malignant biliary obstruction. Serum bilirubin levels were assessed in 48 patients; the mean value prior to intervention was 15.0 mg/dl.ResultsIn 12 patients (21%) complications occurred as a result of percutaneous transhepatic drainage. Stent implantation was complicated in 13 patients, but was possible in all patients. A significant decrease in bilirubin level was seen in 83.3% of patients following stent implantation. Approximately 30% of patients developed recurrent jaundice after a mean 97.1 days. In 9 patients (15%) the recurrent jaundice was caused by stent occlusion due to tumor growth. The mean follow-up was 141.8 days, the mean survival 118.7 days. Patients with cholangiocarcinomas and gallbladder carcinomas had the best results. Worse results were seen in patients with pancreatic tumors and with lymph node metastases of colon and gastric cancers.ConclusionsThe main predictive factors for occlusion rate and survival are the type of primary tumor, tumor stage, the decrease in bilirubin level, and the general condition of the patient.

Value of Mr Mammography in the Detection and Exclusion of Recurrent Breast Carcinoma

PURPOSE This is a study of 140 patients undergoing MR mammography (MRM) for evaluation of possible local recurrent disease following breast-conserving surgical treatment of mammary carcinoma. MRI was performed 1-228 months (mean 28.3 months) postoperatively. METHOD MRM and interpretation of the dynamic measurements were performed in a standardized manner after positioning the patient in a double breast coil. A GRE sequence (Flash 3D, TE 5 ms, TR 12 ms, FA 25 degrees) was acquired before and 1, 2, 3, and 8 min after intravenous injection of Gd-DTPA in a dose of 0.15 mmol/kg body wt. RESULTS Recurrent disease was excluded in 82.8% of cases with MRM. In another 13.6% of patients, MRM was able to reliably detect recurrence of malignancy. In five cases (3.6%), MRM returned false-positive results. CONCLUSION MRM is a sensitive method for detecting or excluding recurrence of malignant disease. It remains to be determined whether early detection of recurrent disease can contribute significantly to improving the prognosis in these patients.

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 Crohns 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.

MR mammography: influence of menstrual cycle on the dynamic contrast enhancement of fibrocystic disease.

Abstract. Magnetic resonance mammography (MRM) provides data regarding the nature of tumours based on contrast medium dynamics; fibrocystic changes in the breast, however, may lead to false-positive results. This study investigated whether the contrast medium dynamics of fibrocystic changes are dependent on the menstrual cycle. Twenty-four patients with palpable lumps but normal mammographies and ultrasound studies were examined. The MRM technique was performed during the first and second part of the menstrual cycle using a FLASH 3D sequence, both native and at 1, 2, 3 and 8 min after intravenous application of 0.15 mmol/kg body weight of gadodiamide. The calculated time–intensity curves were evaluated based on the following criteria: early percentage of contrast medium uptake in relation to the native value; formation of a plateau phenomenon after the second minute; the point of maximal contrast medium uptake; and calculation of the contrast enhancing index. During the second half of the menstrual cycle, a generally greater contrast medium uptake was observed. Nevertheless, when further diagnostic criteria, such as continuous contrast medium increase as a function of time, were considered, there was no increased rate of false-positive findings. The phase of the menstrual cycle may affect the specificity of the examination, if only the quantitative contrast medium uptake and the percentage of contrast medium uptake in the first 2 min are considered. A control MRM during the other half of the cycle may then be indicated and additional diagnostic criteria may improve specificity.