Development of contrast-enhanced virtual MR cholangioscopy: a feasibility study

The purpose of this study was to examine the feasibility of contrast-enhanced virtual MR cholangioscopy (CE VMRC). Intraluminal views of the extrahepatic biliary tree were generated in ten patients undergoing abdominal MRI post mangafodipir trisodium administration employing coronal 2.5-mm 3D fast low-angle shot (FLASH) images (TR 6.8 ms, TE 2.3 ms, matrix 195 x 512) with fat saturation and a commercially available software. Contrast-enhanced VMRC was compared with single-shot turbo spin-echo T2-weighted MR cholangiography (T2 MRC) in terms of ductal visualization and artifact presence, utilizing a five-point grading scale. Four anatomic segments were evaluated: the intra- and extra-pancreatic segment of the common bile duct (CBD), and the cystic duct and the area of hepatic duct bifurcation. Both CE VMRC and T2 MRC depicted 38 of 40 segments. There were no significant differences between CE VMRC and T2 MRC in ranking ductal segments visualization ( p=0.27). The high contrast between intraluminal fluid and extraluminal tissues facilitated the generation of endoscopic views. Contrast-enhanced virtual MR cholangioscopy is a feasible technique providing endoscopic views of the CBD. Initial results show correlation of CE VMRC with projectional MR cholangiography.

Peripheral primitive neuroectodermal tumour during pregnancy

The case of a 25-year-old primipara in the second trimester of pregnancy, suffering from a peripheral primitive neuroectodermal tumour (pPNET) diagnosed by bone biopsy, is described. External irradiation was initially performed because of Jacksonian seizures due to a lesion in the right cerebral hemisphere. Appropriate shielding was used to reduce fetal exposure during brain radiotherapy. Caesarian delivery at the 27th week of gestation was performed because of tumour progression. The neonate had no evidence of disease and survived for 1 month. However, the placenta and ovaries showed metastases from the maternal pPNET. The patient died 14 months after initial diagnosis owing to the aggressiveness of the tumour, the rapid and extensive semination (bone marrow, lung, liver, craniospinal axis involvement) and the inability to adequately treat the patient with appropriate doses of chemotherapy.

Colonic tuberculosis mimicking Crohn's disease: case report

BACKGROUND

Intestinal tuberculosis is a rare disease in western countries, affecting mainly immigrants and immunocompromised patients. Intestinal tuberculosis is a diagnostic challenge, especially when active pulmonary infection is absent. It may mimic many other abdominal diseases.

CASE PRESENTATION

Here, we report a case of isolated colonic tuberculosis where the initial diagnostic workup was suggestive of Crohn's disease. Computed tomography findings however, raised the possibility of colonic tuberculosis and the detection of acid-fast bacilli in biopsy specimens confirmed the diagnosis.

CONCLUSIONS

In conclusion, this case highlights the need for awareness of intestinal tuberculosis in the differential diagnosis of chronic intestinal disease

MR enteroclysis protocol optimization: comparison between 3D FLASH with fat saturation after intravenous gadolinium injection and true FISP sequences

The aim of this study was to introduce the true fast imaging with steady-state precession (FISP) sequence for MR enteroclysis and compare it with the already used T1-weighted fast low-angle shot (FLASH) sequence. Twenty-one patients underwent both MR and conventional enteroclysis. The MR enteroclysis examination was performed after administration of an iso-osmotic water solution through a nasojejunal catheter and the following sequences were included: (a) true FISP; and (b) 3D FLASH with fat saturation after intravenous injection of 20 mg Buscopan or 1 mg glucagon and 0.1 mmol/kg gadolinium chelates. The true FISP sequence provided images with significantly fewer motion artifacts, whereas 3D FLASH was less sensitive to susceptibility and chemical shift artifacts. The homogeneity of endoluminal opacification, wall conspicuity, and distention of the small bowel were very good to excellent and the two sequences presented no statistically significant differences here. True FISP provided significantly better overall image quality than did 3D FLASH. The true FISP sequence can provide good anatomic demonstration of the small bowel on T2-like images and could be combined with T1-weighted FLASH images for an integrated protocol of MR enteroclysis.

Contrast-enhanced magnetic resonance cholangiography versus heavily T2-weighted magnetic resonance cholangiography

RATIONALE AND OBJECTIVES

To investigate the feasibility of contrast-enhanced magnetic resonance cholangiography (CE-MRC) and compare it with single-shot turbo spin-echo magnetic resonance cholangiography (SSTSE-MRC).

METHODS

Fifteen patients with suspected metastatic liver disease (n = 10) or biliary tree abnormalities (n = 5) underwent a magnetic resonance imaging (1.5-T system) examination before and after mangafodipir administration. Contrast-enhanced MRC with a three-dimensional fast low-angle shot sequence after mangafodipir trisodium administration was compared with SSTSE-MRC. Four anatomic segments were evaluated: the intrapancreatic and extrapancreatic common bile duct segments, the cystic duct, and the area of hepatic bifurcation. Contrast-enhanced MRC and SSTSE-MRC were separately analyzed on a 5-point grading scale in terms of ductal segment visualization and lumen narrowing or dilatation.

RESULTS

There was no difference (P = 0.375) in segment visualization between CE-MRC and SSTSE-MRC; 56 of the 60 segments were visualized by both techniques. In the evaluation of ductal narrowing or dilatation, nonsignificant differences (P = 0.500) were observed. Contrast-enhanced MRC was not influenced by fluid superimposition and provided additional information from background tissues.

CONCLUSIONS

Contract-enhanced MRC is a feasible technique showing anatomic correlation with SSTSE-MRC, and it can in addition provide functional information. Contrast-enhanced MRC may be used in selected patients when traditional SSTSE-MRC is inconclusive.

MR enteroclysis imaging of Crohn disease

Magnetic resonance (MR) enteroclysis imaging is emerging as a technique for evaluation of the small bowel in patients with Crohn disease. Administration of 1.5-2 L of isosmotic water solution through a nasojejunal catheter ensures distention of the bowel and facilitates identification of wall abnormalities. True fast imaging with steady-state precession (FISP), half-Fourier acquisition single-shot turbo spin-echo (HASTE), and postgadolinium T1-weighted three-dimensional fast low-angle shot sequences can be employed in a comprehensive and integrated MR enteroclysis examination protocol to overcome specific disadvantages of each of the sequences involved. Superficial abnormalities that are ideally delineated with conventional enteroclysis are not consistently depicted with MR enteroclysis. The characteristic transmural abnormalities of Crohn disease such as bowel wall thickening, linear ulcers, and cobblestoning are accurately shown with MR enteroclysis imaging, especially with the true FISP sequence. MR enteroclysis is comparable to conventional enteroclysis in the detection of the number and extent of involved small bowel segments and in the disclosure of luminal narrowing or prestenotic intestinal dilatation. The clinical utility of MR enteroclysis in Crohn disease has not been fully established. At present, the method may be used for follow-up studies of known disease, estimation of disease activity, and determination of the extramucosal extent and spread of the disease process.

Estimation of spleen volume using MR imaging and a random marking technique

The aim of this study was to apply a random marking volumetric technique in MR images for estimation of spleen volume. The MR imaging was performed in phantoms and 16 patients with indications unrelated to splenic disease. Images were transferred to a workstation to perform volumetric measurements using the random marking technique and the conventional technique of manual planimetry. Two observers independently measured splenic volume in order to evaluate reproducibility of both volumetric techniques. Phantom experiments revealed that the accuracy of the random marking technique and manual planimetry was approximately the same. In vivo splenic volume measurements derived from both volumetric techniques were highly correlated (r = 0.99, p < 0.0001). For both observers intraobserver variation was found to be lower with the random marking technique than with manual planimetry. Interobserver coefficient of variation using the manual planimetry was 4.6% and was reduced to 2.9% by adopting the random marking technique. The random marking technique was almost two times faster than the manual planimetry. The combination of the random marking technique with MR imaging might provide accurate, reproducible, quick splenic volume estimations.

Pulmonary sarcoidosis. Correlation of expiratory high-resolution CT findings with inspiratory patterns and pulmonary function tests

PURPOSE

To assess the presence and extent of air trapping (AT) on chest high-resolution CT (HRCT) in sarcoidosis and to correlate such findings with patterns, lesion extent on inspiratory CT and pulmonary function tests (PFT).

MATERIAL AND METHODS

Thirty patients with sarcoidosis underwent inspiratory and expiratory HRCT and PFT. HRCT images were evaluated for presence, distribution and AT extent as well as the predominant HRCT pattern and the extent of lesions at inspiration. Attenuation difference in the AT regions at expiration and at inspiration were calculated. The presence and extent of AT were correlated with PFT, extent of involvement and predominant inspiratory patterns.

RESULTS

AT was present in 25/30 patients with no lung zone predilection. AT was the only CT indication of pulmonary sarcoidosis in 3/30 patients who also had normal PFT. Attenuation difference between inspiration and expiration ranged from -40 HU to 106 HU. In 2 patients, a paradoxical decrease of lung attenuation was observed at expiration. A significant correlation was found between AT extent at expiration, with residual volume-total lung capacity ratio and residual volume.

CONCLUSION

AT is an additional HRCT finding in sarcoidosis. AT may involve any lung zone, including costophrenic angles and may be the only CT feature of pulmonary sarcoidosis. Strong correlation is only found with PFT values that are specific for incomplete lung emptying at expiration.

An individualized approach for the implantation of a humeral prosthesis with the proper retroversion in fractures

We applied a new methodology in 7 patients with a fracture of the upper humeral head that required hemiarthroplasty, to implant a humeral prosthesis with an individualized posterior version. Our goal was to determine preoperatively the distance from the posterior edge of the bicipital groove where the lateral fin of the humeral prosthesis should sit, in order to reproduce the individual retroversion during surgery. Using three computed tomography scan sections of the upper humerus and image processing software, we estimated the above-mentioned distance in the sound humerus and implanted the prosthesis in each patient accordingly. The differences in retroversion between the left and right humeral heads permit a better approximation to normal applying this methodology than inserting the prosthesis in a standard retroversion.

Image segmentation in treatment planning for prostate cancer using the region growing technique

The purpose of this study was to evaluate the performance of a region growing technique for segmenting prostate, bladder and rectum in CT images of prostate cancer patients. Prostate, bladder and rectum were segmented in all CT images of 10 patients using the region growing technique and manual tracing. Volumes of the above organs computed with the region growing technique were compared with those from manually traced images on a slice-by-slice basis. Measurement reproducibility of both segmentation techniques was evaluated using the data obtained from four independent observers. The region growing technique was 1.5 times faster than manual tracing. There was no statistical difference between the slice volumes of prostate, bladder and rectum obtained by the two segmentation techniques (p > 0.05, paired Student's t-test). Correlation between slice volumes of all organs of interest provided both by region growing and by manual tracing was very good (prostate r2 = 0.84; bladder r2 = 0.93; rectum r2 = 0.85). An overall reasonable agreement was found between the two segmentation techniques. The intraobserver and interobserver variations for prostate, bladder and rectum volume segmentation were found to be lower with the region growing technique than with manual tracing. The suggested semi-automatic technique allows the possibility of generating accurate and reproducible segmentation of prostate, bladder and rectum from CT data with great saving in labour.

Role of conventional radiology in the diagnosis and staging of gastrointestinal tract neoplasms

Preoperative diagnosis and staging of primary gastrointestinal (GI) neoplasms are challenges for both clinicians and radiologists. Barium studies are very sensitive in disclosing primary malignancies, even at an early stage. Radiologic signs depend on the evolutional stage of the disease and its appearance on gross pathology. A neoplasm may be manifested on barium studies by a wide spectrum of findings, including mucosal abnormalities, mass presence, ulcerative lesions, submucosal infiltration, and lumen stenosis. Advanced disease can be accurately diagnosed, whereas early cancer should be differentiated from other neoplastic or inflammatory disorders by meticulous analysis of radiologic findings. The extent of GI involvement and multiplicity of the lesions can be assessed on barium studies. In the staging of GI neoplasms, barium studies are of little value. Skeletal survey by conventional radiographs and chest plain films can reveal distant metastases in a short time and with low cost, although they are not that sensitive to the detection of early or subtle lesions. The exact role of conventional radiology in the imaging workup of GI malignancies depends on local expertise and availability of other diagnostic techniques and modalities.

The bicipital groove as a landmark for orientation of the humeral prosthesis in cases of fracture

We studied 45 dry cadaveric humeri to determine whether the bicipital groove of the humerus can be used as a landmark for a proper, individualized orientation of a humeral prosthesis, especially in the case of a fracture. We performed 3 computed tomography sections (at a level just below the lower portion of the head, at the middle of the humeral head, and at a distance 5 cm below the first section), and we used special software for 3-dimensional image processing. To reproduce the individual posterior version of the head, when a humeral prosthesis is implanted for fracture, the lateral fin of the prosthesis should be a mean distance 5.2 +/- 2.6 mm (-1.5 to 10.7 mm) from the posterior edge of the bicipital groove. If the lateral fin of the humeral prosthesis seats just behind the posterior edge of the bicipital groove, a difference of -6.3 degrees to 41.7 degrees from the normal posterior version occurs. A new, simple methodology for an individualized posterior version of a humeral prosthesis in cases of fracture is proposed. We applied this in 6 consecutive patients with fracture of the humeral head that required hemiarthroplasty.

Late complication following percutaneous cholecystostomy: retained abdominal wall gallstone

A case of recurrent abdominal wall abscess following percutaneous cholecystostomy (PC) is presented. Transperitoneal PC was performed in an 82-year-old female with calculous cholecystitis. Symptoms resolved and the catheter was removed 29 days later. The patient came back 5 months later with a superficial abscess that was drained and 8 months post PC with a fistula discharging clear fluid. Ultrasonography revealed the tract adjacent to an area of inflammation containing a calculus, whereas CT failed to depict the stone. Subsequent surgery confirmed US findings. To our knowledge, this is the first report of a dislodged bile stone following percutaneous cholecystostomy.

MR imaging of the small bowel with a true-FISP sequence after enteroclysis with water solution

RATIONALE AND OBJECTIVES

To evaluate a novel MR enteroclysis technique for small-bowel imaging.

METHODS

Twenty-one patients with suspected small-bowel disease underwent both MR and conventional enteroclysis. MR enteroclysis was performed by injecting an iso-osmotic water solution through a nasojejunal catheter with a flow rate of 80 to 150 mL/min. A maximum of 2 L of water solution was administered. A dynamic heavily T2-weighted single-shot turbo spin-echo sequence was applied in coronal orientation to monitor the bowel filling and adequate distention. Twelve 4-mm-thick slices were acquired by using a true fast imaging with steady-state precession (true-FISP) sequence during an 18-second breath-hold interval. Small-bowel distention, wall conspicuity, homogeneity of opacification, and the presence of artifacts were subjectively evaluated by two reviewers using five-point scales.

RESULTS

Chemical shift artifacts were low and ghost artifacts were absent. Susceptibility artifacts were more prominent in the ileum; motion artifacts were low in the jejunum, ileum, and ileocecal area. Homogeneity of opacification was very good in the jejunum, good to very good in the ileum, and good in the ileocecal area. Distention was very good to excellent in the jejunum and ileum and very good in the ileocecal area. Wall conspicuity was very good to excellent in the jejunum and ileum.

CONCLUSIONS

MR enteroclysis with the true-FISP sequence produced high-quality images of the small bowel. Further clinical studies are required to determine the clinical efficacy of the new technique compared with conventional enteroclysis.

Frontal lobe abscess secondary to head trauma and nasal polyposis

Cerebral frontal lobe abscess may be a frequent intracranial complication of paranasal sinusitis. An unusual case of cerebral abscess complicating massive polyposis is described in a patient with history of previous severe head trauma 30 years ago. Imaging evaluation using both computed tomography and magnetic resonance imaging is important to diagnose such rare entities.

Miliary hepatic tuberculosis not associated with splenic or lung involvement. A case report

Miliary hepatic involvement is a frequent finding on autopsy in patients with disseminated tuberculosis. Imaging studies may reveal hepatosplenomegaly and/or parenchymal inhomogeneity and, in a minority of cases, focal lesions, invariably associated with miliary lung disease. An unusual case of disseminated tuberculosis with manifestations of miliary hepatic involvement, abdominal and neck lymphadenopathy on US and CT without any evidence of active disease in the lungs, spleen or other organ, is described.

Malignant peritoneal mesothelioma presenting with respiratory symptoms

Malignant peritoneal mesothelioma is a rare disease associated with mild, nonspecific abdominal symptoms and a wide spectrum of imaging findings, with thickened mesentery and peritoneum being the most common ones. A case of a malignant peritoneal mesothelioma presenting with manifestations of pulmonary disease is reported. Imaging evaluation revealed pleural, lung and pericardial involvement together with retroperitoneal lymphadenopathy, little ascites and extensive omental, but only subtle, mesenteric thickening.

CT evaluation of mesenteric panniculitis: prevalence and associated diseases

OBJECTIVE

This study was undertaken to assess the prevalence of mesenteric panniculitis on CT and to describe its appearance and associated diseases.

SUBJECTS AND METHODS

A total of 7620 consecutive abdominal CT examinations were prospectively evaluated for features common to mesenteric panniculitis such as a well-delineated inhomogeneous hyperattenuated fatty mass at the mesenteric root, envelopment of mesenteric vessels, and no evidence of invasion of the adjacent small-bowel loops that may be displaced.

RESULTS

CT findings of mesenteric panniculitis were seen in 49 patients (0.6%). We found a female predominance. Mesenteric panniculitis coexisted with malignancy in 34 patients and with benign disorders in 11 patients. In the remaining four patients, mesenteric panniculitis, verified on histology, was considered to be responsible for the patients' clinical manifestations; no other abnormality was identified. Soft-tissue nodules (n = 39) and a fatty halo surrounding vessels and nodules (n = 42) were observed in most patients. Follow-up abdominal CT examinations in 29 of the 49 patients showed changes in only one patient.

CONCLUSION

CT findings of mesenteric panniculitis may be seen in patients undergoing abdominal CT for various symptoms.

Abdominal helical CT: milk as a low-attenuation oral contrast agent

One hundred ten consecutive patients were given either whole (4%) milk, 2% milk, water, barium suspension, or no oral contrast agent before abdominal computed tomography (CT). Results with whole milk were superior to those with all other agents for gastrointestinal distention, mural visualization, and pancreas-duodenum discrimination. In bowel loop discrimination, results with 4% milk were equal to those with barium but superior to those with all other agents. Whole (4%) milk is an effective low-attenuation oral contrast agent.