Pneumobilia: where to look for on hepatic MR imaging?

The presence of pneumobilia is a particular problem in magnetic resonance cholangiopancreatography (MRPC) and may create an appearance that can be mistaken for intraductal stones. Compared with biliary stones, however, pneumobilia causes a susceptibility artifact on hepatic MR imaging and appears as a signal void on a dual echo gradient MR sequence, such as the T1-weighted in-phase and opposed-phase gradient echo sequence. This susceptibility artifact is more pronounced on the gradient echo image with the longer echo time due to the continued decay of the transverse magnetization. Besides identification of hepatic steatosis, the double echo approach is particularly helpful in identification of pneumobilia.     

Combined small and large bowel MR imaging in patients with Crohn’s disease: a feasibility study

MRI of the small bowel is a new method for the assessment of inflammatory bowel diseases. However, inflammatory bowel disease can affect both the small and large bowel. Therefore, our goal was to assess the feasibility of displaying the small bowel and colon simultaneously by MR imaging. Eighteen patients with inflammatory bowel disease were studied. For small bowel distension, patients ingested a solution containing mannitol and locust bean gum. Furthermore, the colon was rectally filled with water. MR examinations were performed on a 1.5-T system. Before and after intravenous gadolinium administration, a T1w data set was collected. All patients underwent conventional colonoscopy as a standard of reference. The oral ingestion and the rectal application of water allowed an assessment of the small bowel and colon in all patients. By means of MRI (endoscopy), 19 (13) inflamed bowel segments in the colon and terminal ileum were detected. Furthermore, eight additional inflammatory lesions in the jejunum and proximal ileum that had not been endoscopically accessible were found by MRI. The simultaneous display of the small and large bowel by MRI is feasible. Major advantages of the proposed MR concept are related to its non-invasive character as well as to the potential to visualize parts of the small bowel that cannot be reached by endoscopy.     

Alphavbeta3-integrin imaging: a new approach to characterise angiogenesis?

OVERVIEW: The field of angiogenesis research is one of the most rapidly growing biomedical disciplines. Great efforts are being made to develop anti-angiogenesis drugs for treatment of cancer as well as non-oncological diseases. Thus, imaging techniques allowing non-invasive monitoring of corresponding molecular processes will be of great interest. One target structure involved in the angiogenic process is the integrin alphavbeta3, which mediates the migration of activated endothelial cells during vessel formation. MATERIALS AND METHODS: A variety of radiolabelled RGD peptides have been introduced for monitoring of alphavbeta3 expression using nuclear medicine tracer techniques. OBJECTIVES: This review discusses tracer development and highlights some strategies for tracer optimisation. It summarises the preclinical and clinical data and discusses the potential of this class of tracer to characterise angiogenesis.     

Combined arterial and venous whole-body MR angiography with cardiac MR imaging in patients with thromboembolic disease—initial experience

The objective was to assess the feasibility of a combined arterial and venous whole-body three-dimensional magnetic resonance (MR) angiography, together with a cardiac MR examination, in patients with arterial thromboembolism. Ten patients with arterial thromboembolism underwent a contrast-enhanced whole-body MR examination of the arterial and venous vessels, followed by a cardiac MR examination on a separate occasion within 24 h. All examinations were performed on a 1.5-T MR scanner. For both arterial and venous MR angiography only one injection of contrast agent was necessary. The cardiac imaging protocol included dark-blood-prepared half-Fourier acquisition single-shot turbo-spin-echo sequences, fast steady-state free precession cine sequences, T2-weighted turbo-spin-echo sequences and inversion recovery gradient-echo fast low-angle-shot sequences after injection of contrast agent. MR imaging revealed additional clinically unknown arterial thromboembolisms in four patients. The thoracic aorta was depicted as embolic source in four patients, while deep vein thrombosis (DVT) was found in one patient as the underlying disease. Unsuspected infarction of parenchymal organs was detected by MRI in two patients. An unknown additional DVT was found in one patient. Four patients were considered to have arterial emboli of cardiac origin. In conclusion, acquisition of arterial and venous MR angiograms of the entire vascular system combined with cardiac MR imaging is a most comprehensive and valuable strategy in patients with arterial thromboembolism.     

Diffusion-weighted MR imaging in comparison to integrated [¹⁸F]-FDG PET/CT for N-staging in patients with lung cancer

Purpose The purpose of this study was to prospectively determine the diagnostic accuracy of diffusion-weighted imaging (DWI) using MRI in the staging of thoracic lymph nodes in patients with lung cancer, and to compare the performance to that of PET/CT.     

Hoffa’s fat pad injuries and their relationship with anterior cruciate ligament tears: new observations based on MR imaging in patients and MR imaging and anatomic correlation in cadavers

Purpose To determine the normal anatomic relationships of Hoffa’s fat pad with the anterior cruciate ligament (ACL) and with the frequency of Hoffa’s fat pad abnormalities in ACL-deficient knees. Design Retrospective clinical study on patients and observational anatomic study on cadavers. The study was approved by the Institutional Review Board. Patients MR imaging studies of the knees of 100 patients (21–48 years old) with or without arthroscopically proven tears of the ACL, performed at a single institution, were reviewed by two readers for abnormalities of Hoffa’s fat pad. Ten cadaveric knee specimens were studied with MR imaging and Faxitron radiographs, and by inspection of sections and histology. Results Alterations in Hoffa’s fat pad on MR imaging were present in 64% (32/50) of patients with torn ACLs, and in 24% (12/50) of patients without a tear of the ACL (P < 0.05). Hoffa’s fat pad inserted into the intercondylar notch in 50% (5/10) of cadaveric specimens, four in conjunction with the ligamentum mucosum and in one in an isolated fashion. Histological study demonstrated the composition of the ligamentum mucosum and Hoffa’s fat pad and their course and insertion sites in the intercondylar notch. Conclusion Abnormalities of Hoffa’s fat pad, such as focal and diffuse edema, tears, scars and synovial proliferation, are more common in knees with torn ACLs than in knees with intact ACLs.     

123I-FP-CIT SPECT imaging of dopamine transporters in patients with recurrent sudden falls: are such falls a distinct entity?

Recurrent falls in older people are commonly associated with abnormalities that involve several parts of the central nervous system, especially with basal ganglion pathology. The aim of the present study was to evaluate the integrity of striatal dopamine transporters (DaTs) by use of (123)I-N-3-fluoropropyl-2beta-carbomethoxy-3beta-(4-iodophenyl)tropane ((123)I-FP-CIT) SPECT of striatal DaTs in patients with recurrent sudden falls. METHODS: Twenty-one patients without a definite neurologic diagnosis for recurrent sudden falls were enrolled in a cross-sectional study. SPECT with a DaT ligand was performed 180 min after injection of 185 MBq of (123)I-FP-CIT with a dual-head gamma-camera. RESULTS: DaT SPECT findings were normal in 15 of 21 patients (71%). Of those, 73% had abnormal MRI findings suggestive of atherosclerotic lesions. Eleven patients with normal DaT SPECT findings had mild parkinsonian symptoms. There was no correlation of the SPECT results with patient age, duration of occurrence of falls, or frequency of falls, and there was no significant difference in the relative distributions of SPECT findings between patients with and patients without parkinsonian symptoms or vascular risk factors. CONCLUSION: Recurrent sudden falls are, in most cases, not attributable to the degeneration of the nigrostriatal system.     

Assessment of activity of Crohn’s disease of the ileum and large bowel: proposal for a new multiparameter MR enterography score

Purpose

We evaluated the diagnostic accuracy of magnetic resonance enterography (MR-E) in assessing Crohn’s disease (CD) activity by differentiating acute, chronic and remission stages of disease through a quantitative MR-E assessment.

Materials and methods

One hundred patients with a histological diagnosis of CD were studied with MR-E. Intestinal distension was obtained by oral administration of approximately 2 L of a polyethylene glycol solution (PEG). In all cases, the ileum and large bowel were imaged with morphological sequences (heavily T2-weighted single-shot, dual fast-field echo, balanced fast-field echo) and a postcontrast dynamic sequence (T1-weighted high-resolution isotropic volume excitation). Disease activity was assessed according to a multiparameter score (0–8) based on lesion morphology, signal intensity and contrast enhancement. MR-E findings were compared with clinical-laboratory data and disease activity indices [Crohn’s Disease Activity Index (CDAI); Inflammatory Bowel Disease Questionnaire (IBDQ)]. Multiple regression analysis was performed by correlating MR-E score, CDAI and IBDQ. Frequencies were then compared using the χ ² test.

Results

MR-E identified inactive disease in 9% of cases, chronic disease in 57% and active disease in the remaining 34%. The most frequently involved bowel segment was the terminal ileum (52%). A statistically significant correlation was found between MR-E score and CDAI (R=0.86; p<0.001) and between MR-E score and IBDQ (R=?0.83; p<0.001). The most suggestive parameter for disease activity was layered bowel-wall enhancement, a finding predominantly present in patients with increased CDAI (≥150) and/or local complications (χ ²=7.13; p<0.01).

Conclusions

MR-E is a noninvasive and diagnostic imaging modality for CD study and follow-up. The MR-E score proposed in this study proved to be useful in assessing disease severity and monitoring response to treatment.     

MR imaging of the salivary glands in sicca syndrome: comparison of lipid profiles and imaging in patients with hyperlipidemia and patients with Sjögren's syndrome

OBJECTIVE: We correlated abnormalities on MR imaging with the plasma lipid profiles of patients with hyperlipidemia and symptoms of sicca syndrome. SUBJECTS AND METHODS: MR imaging features of the salivary glands, salivary function, immunologic abnormalities, and plasma lipid profiles were analyzed in 24 patients with hyperlipidemia and symptoms of sicca syndrome and compared with those of 50 patients with Sj?gren's syndrome. RESULTS: Swelling of the parotid gland, impaired salivary flow, or both were observed in 20 (83%) of 24 patients with hyperlipidemia and symptoms of sicca syndrome. MR imaging findings included an enlarged parotid gland replaced with extensive lipid infiltration, whereas sialography of the parotid gland revealed normal findings. Immunologic studies and analyses of the labial glands of the mouth revealed distinctive features in patients with Sj?gren's syndrome. Importantly, elevated levels of plasma triglyceride correlated with parotid gland swelling, and increased cholesterol levels significantly affected salivary flow. CONCLUSION: Our findings suggest a distinct entity of sicca syndrome in patients with hyperlipidemia compared with patients with Sj?gren's syndrome. Characteristic MR imaging findings of salivary glands in patients with hyperlipidemia included extensive lipid infiltration and gland enlargement.     

Chronological evaluation of liver enhancement in patients with chronic liver disease at Gd-EOB-DTPA-enhanced 3-T MR imaging: does liver function correlate with enhancement?

Purpose  

To investigate the chronological relationship between scan delay and liver enhancement for the hepatobiliary phase on Gd-EOB-DTPA-enhanced MRI and evaluate the effects of liver function on liver enhancement.     

Magnetic resonance imaging for evaluation of disease activity in Crohn’s disease: a systematic review

To systematically review the evidence on the accuracy of MRI for grading disease activity in Crohn’s disease (CD). The MEDLINE, EMBASE, CINAHL and Cochrane databases were searched for studies on the accuracy of MRI in grading CD compared to a predefined reference standard. Two independent observers scored all relevant data. Three disease stages were defined: remission, mild and frank disease. The accuracy rates of MRI per disease stage were calculated by means of a random-effects model. Seven studies were included from a search resulting in 253 articles. In total 140 patients (16 patients in remission, 29 with mild disease and 95 with frank disease) were used for data analysis. MRI correctly graded 91% (95% CI: 84–96%) of patients with frank disease, 62% (95% CI: 44–79) of patients with mild disease and 62% (95% CI: 38–84) of patients in remission. MRI more often overstaged than understaged disease activity; MRI overstaged disease activity in 38% of patients in remission, mostly as mild disease. Overstaging of mild disease was observed in 21%, understaging in 17%. MRI correctly grades disease activity in a large proportion of patients with frank disease. For patients in remission or with mild disease, MRI correctly stages disease activity in many patients (62%).     

CT and MR imaging of the “target sign” in metastatic brain disease

The “target sign” is a common finding in granulomatous infection. A case with the target sign in metastatic brain tumor from small cell lung carcinoma is reported. Received: 28 September 1998; Revised: 15 March 1999; Accepted: 15 April 1999     

US, CT, and MR imaging of hepatic masses in Alström syndrome: a case report

Alstr?m syndrome is among the rarest genetic disorders described in the medical literature. It is characterized by retinal pigment degeneration, obesity, sensorineural deafness, non-insulin-dependent diabetes mellitus, progressive chronic nephropathy, cardiomyopathy, and hepatic dysfunction. Hepatic inflammation and fibrosis, which leads to cirrhosis, portal hypertension, and liver failure, is the final pathway of the hepatopathy in Alstr?m syndrome. We report a case of Alstr?m syndrome with particular emphasis on hepatic findings.