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Abstract: Purpose: The clinical and morphologic outcome of patients with obstructed defecation syndrome after stapled transanal rectal resection was prospectively evaluated. Methods: Twenty-four consecutive patients (22 women; median age, 61 (range, 36–74) years) who suffered from obstructed defecation syndrome and with rectal redundancy on magnetic resonance defecography were enrolled in the study. Constipation was assessed by using the Cleveland Constipation Score. Morphologic changes were determined by using closed-configuration magnetic resonance defecography before and after stapled transanal rectal resection. Results: After a median follow-up of 18 (range, 6–36) months, Cleveland Constipation Score significantly decreased from 11 (range, 1–23) preoperatively to 5 (range, 1–15) postoperatively (P = 0.02). In 15 of 20 patients, preexisting intussusception was no longer visible in the magnetic resonance defecography. Anterior rectoceles were significantly reduced in depth, from 30 mm to 23 mm (P = 0.01), whereas the number of detectable rectoceles did not significantly change. Complications occurred in 6 of the 24 patients; however, only two were severe (1 bleeding and 1 persisting pain requiring reintervention). Conclusions: Clinical improvement of obstructed defecation syndrome after stapled transanal rectal resection correlates well with morphologic correction of the rectal redundancy, whereas correction of intussusception seems to be of particular importance in patients with obstructed defecation syndrome.

Infection with Yersinia enterocolitica(YE) typically presents with mild gastroenteritis without systemic infection. However, systemic YE infection has been described in states of iron overload. We present the case of a patient with sepsis with hepatic abscesses due to YE infection. Workup revealed a past diagnosis of diabetes mellitus and hemochromatosis which had been untreated for the previous 5 years due to patient refusal. This case highlights risk factors for systemic infection with YE. A high degree of suspicion for YE infection is warranted in patients with iron overload, diabetes mellitus, or immunosuppression.

To evaluate the diagnostic efficacy (accuracy, sensitivity, specificity) of 1.0 M gadobutrol versus 0.5 M gadopentetate for the classification of lesions as either benign or malignant in patients with known or suspected liver lesions.

The objective of this work was to investigate the clinical and histologic features of patients with pseudocystic lesions of the ligamentum flavum in the lumbar region of the spinal canal and ascertain the existence of genuine ligamentum flavum pseudocysts.

To evaluate position related changes of the menisci in asymptomatic volunteers based on MR imaging of the knee in different positions.

Purpose. To develop a magnetic resonance imaging (MRI) technique for assessing in vivoproperties of orally ingested gastric-retentive tablets under physiologic conditions. Methods. Tablets with different floating characteristics (tablet A-C) were marked with superparamagnetic Fe3O4particles to analyze intragastric tablet position and residence time in human volunteers. Optimal Fe3O4concentration was determined in vitro. Intragastric release characteristic of one slow-release tablet (tablet D) was analyzed by embedding gadolinium chelates (Gd-DOTA) as a drug model into the tablet. All volunteers underwent MRI in the sitting position. Tablet performance was analyzed in terms of relative position of tablet to intragastric meal level (with 100% at meal surface), intragastric residence time (min) and Gd-DOTA distribution volume (% of meal volume). Results. Intragastric tablet floating performance and residence time of tablets (tablet A-D) as well as the intragastric Gd-DOTA distribution of tablet Dcould be monitored using MRI. Tablet floating performance was different between the tablets (A, 93%(95 − 9%); B, 80%(80 − 68%); C, 38%(63 − 32%); p < 0.05). The intragastric distribution volume of Gd-DOTA was 19.9% proximally and 35.5% distally. Conclusions. The use of MRI allows the assessment of galenic properties of orally ingested tablets in humans in seated position.

Purpose:The purpose of this study was to assess accuracy and reliability of a volumetric analysis of abdominal aneurysms on the basis of multidetector row computed tomographic angiography (CTA) and magnetic resonance angiography (MRA) with a commercially available automated vessel analysis software program. Materials and Methods:Twenty patients with abdominal aortic aneurysms underwent preoperative CTA and MRA before endovascular repair. Postdeployment CTA was performed in 15 of these 20 patients (75%). All preoperative CTA and MRA and postdeployment CTA data sets were analyzed with an automated software tool. The length of the stent grafts on postdeployment CTA was measured and compared with the true length of the primary component. Two readers independently evaluated 13 vessel parameters on preoperative CTA and MRA, which are considered to be important in planning stent graft deployment. Results:With the automated analysis software tool, all measurements could be performed on either CTA or MRA data sets. There was no statistically significant difference between postdeployment measurements of stent graft length on CTA and the true dimensions of the implanted stent grafts. Interobserver agreement for all of the measurements with either CTA or MRA was good to excellent (interclass coefficient, 0.71 to 0.99) with only minimal mean differences of measured dimensions between both readers (range, −2.0 to +2.3 mm, Bland-Altman). Intermodality agreement between CTA and MRA was good to excellent (interclass coefficient, 0.62 to 0.98) with small mean differences of measured dimensions between both methods (range, −4.1 to +2.1 mm, Bland-Altman). Conclusion:Volumetric measurement with an automated analysis software tool allows a fast, precise, and reliable noninvasive preoperative determination of all aortic dimensions on the basis of either CTA or MRA data sets. (J Vasc Surg 2003;37:619-27.)

Weight-bearing magnetic resonance (MR) imaging of the spine can either be simulated by imaging the patient in the supine position in combination with a special axial loading device or be achieved by using vertically open-configuration MR systems, which allow for in vivo MR images of the spine under upright weight-bearing conditions in either seated or standing body positions. Weight-bearing MRI of the spine permits the study of physiological as well as pathological changes in the relationships of the intervertebral disk, the spinal canal, and the neural foramina as well as the assessment of segmental instability in physiologic body positions. With this technique, MR images may be taken in painful body positions so that morphological changes of the intervertebral disk or other spinal structures may be correlated with pain or other symptoms. In selected cases, weight-bearing MRI of the spine may demonstrate clinically relevant neural compromise or foraminal stenosis, which may be occult on conventional MR images obtained in the supine position.

To assess practicability of weight-bearing magnetic resonance (MR) imaging of the forefoot, and to demonstrate position-related changes of the neurovascular bundles and the metatarsal heads in asymptomatic volunteers. With an open-configuration MR system, 32 feet of 32 asymptomatic individuals aged 20–60 years were studied in supine and weight-bearing body positions. Transverse T1-weighted spin-echo MR images were performed. MR images were evaluated qualitatively with regard to image quality, visibility, and position-dependent changes of the neurovascular bundle. In addition, the position of the metatarsal heads was analyzed quantitatively. Weight-bearing MR imaging was feasible in all 32 feet. Quality of MR images obtained in the weight-bearing position was superior to that obtained in the supine position (P &lt; 0.05). A change in the position of the neurovascular bundle from below a virtual line paralleling the plantar cortical line to above this line was present in 50 of 61 instances (82%) between the supine and the weight-bearing positions. When changing from the supine to the weight-bearing position, there was a significant decrease in the distance between the plantar skin and the metatarsal heads for the second (mean 4.5 mm), third (mean 4.4 mm), and fourth metatarsal heads (mean 3.7 mm) (P &lt; 0.0001). However, the difference for the first (mean 0.5 mm) and fifth (mean 0.9 mm) metatarsal heads was not significant. Weight-bearing MR imaging of the forefoot is feasible using an open-configuration MR system and demonstrates position-related changes of the neurovascular bundles relative to the metatarsal heads, as well as position-related changes of the metatarsal heads themselves. J. Magn. Reson. Imaging 2002;16:75–84. © 2002 Wiley-Liss, Inc.

The purpose of this study was to evaluate the prevalence and anatomic distribution of occult and palpable ganglia of the foot and ankle as seen by MRI. Within a 7‐year period MRI of the ankle was performed on 2813 patients, and MRI of the foot on 2277 patients using a 1.5T magnet. In all, 167 ganglia in 155 patients were detected. MR images of these patients were reviewed retrospectively by two observers with regard to prevalence, imaging characteristics, and exact anatomic location of ganglia. Clinical findings and (when available) surgical reports were also reviewed. One hundred fifty‐seven ganglia in 145 patients were present on MR images of the ankle, and 10 ganglia in 10 patients on MR images of the foot, resulting in a prevalence of 5.6% (157/2813) in the ankle, and a prevalence of 0.4% (10/2277) in the foot. The most common location was the tarsal sinus or tarsal canal (57/167 ganglia [34.1%]). However, only four of these (7%) were palpable as a soft‐tissue mass. The second most common location was around the Lisfranc joint (23/167 [13.8%]), of which 11/23 [47.8%] were clinically palpable. Palpable ganglia were statistically larger in size than occult ganglia measured in any of three diameters (P= 0.01–0.002). In addition, ganglia of the foot and ankle represented 42% of all clinically suspected soft‐tissue masses. Ganglia in the foot and ankle are an infrequent finding on routine MRI of the foot and ankle. When they occur, these ganglia are most frequently located in the tarsal sinus and tarsal canal, where they are occult to clinical palpation. If ganglia are clinically palpable, they are most commonly located around the Lisfranc joint. In addition, palpable ganglia are larger than occult ganglia. J. Magn. Reson. Imaging 2001;14:464–471. © 2001 Wiley‐Liss, Inc.

. Purpose: To describe the magnetic resonance (MR) appearance and associated clinical findings of partial distal biceps tendon tears. Design: Twenty elbow MR images at 1.5 T, performed over a 7 year period, were reviewed for an appearance of partial tears in the distal biceps. These images were assessed by two musculoskeletal radiologists for the extent of: (a) abnormal signal intensity within the tendon, and the presence of (b) bicipitoradial bursitis, and (c) bony microavulsive injury of the radial tuberosity. Medical records for nine of the 20 cases were reviewed for the clinical findings of ecchymosis, trauma, sensation of a "pop", loss of function, and acuity of onset. Results: Twenty partial distal biceps tendon tears were seen. All displayed an abnormally increased signal in the distal biceps tendon. Three of 20 (15%) showed a 25% to 50% tear, ten of 20 (50%) showed a 50% tear, and seven of 20 (35%) showed a 75% to 90% tear. Bicipitoradial bursitis was seen in 11 of 20 (55%) cases. Bony microavulsive injury of the radial tuberosity was observed in 10 of 20 (50%). Of the nine cases reviewed for associated clinical findings, surprisingly, only three (33%) experienced an acute traumatic episode with an abrupt onset of pain. An insidious onset was reported in four of nine (44%). Sensation of a "pop" was recorded in only two of nine (22%) cases. Ecchymosis and loss of function were not seen in any of the cases. Finally, surgical conformation was obtained for three cases. Conclusion: Partial distal biceps tendon tears have a characteristic MR appearance, demonstrate little functional deficit, and may be attritional in their etiology due to the observation of a low number of patients reporting trauma or an acute onset.

Weishaupt D, Schweitzer ME, Rawool NM, et al. Indirect MR arthrography of the knee Effects of low-intensity ultrasound on the diffusion rate of intravenously administered Gd-DTPA in healthy volunteers. Invest Radiol 2001;36493–499.

Abstract: Objective. Arthrographically, adhesive capsulitis is characterized by decreased joint volume; histologically, the capsule and synovium are thickened. We therefore compared using MR arthrography the joint volumes and capsule/synovial thickness of patients with and without adhesive capsulitis in order to assess the utility of MR arthrography in diagnosing adhesive capsulitis. Design and patients. The 1.5 T MR arthrography images of 28 subjects with (n=9) and without (n=19) adhesive capsulitis were compared. Adhe- sive capsulitis was diagnosed when there was an injected glenohumeral joint volume of less than 10 ml. Two masked observers working in consensus assessed the images for the relative amount of fluid in the biceps tendon sheath and axillary recess, corrugation at the margin of the capsule, capsule/synovial thickness, abnormalities of the rotator interval capsule, and for the presence of a cuff tear. Results. There was a trend towards differences in capsular and synovial thickness (P>0.07) between the subjects with and without adhesive capsulitis; however, the controls had thicker synovium/capsules. Surprisingly, the amount of fluid in the axillary recess and biceps tendon sheath was not significantly different between the groups (P>0.25). There were more tears of the rotator cuff in controls than in patients with adhesive capsulitis (6, 3 vs 1, 1: complete, partial). Also, both corrugation (7 vs 0) and interval abnormalities (7 vs 0) were more common in the controls. Conclusion. There appear to be no useful MR arthrographic signs of adhesive capsulitis. Capsular/synovial thickness, static fluid volume, and the presence of corrugation are inconclusive as MR arthrographic signs for distinguishing shoulders with adhesive capsulitis from those without.

A visualization principle for MR‐guided vascular interventions based on the concerted use of two contrast agents is introduced. The first contrast agent, consisting of small paramagnetic iron oxide particles, was administered intravenously to shorten T1, and even more so T*2, of the blood for extended time periods. The second agent, a monomeric gadolinium complex, was added to a solution in an interventional device, such as a percutaneous‐transluminal‐angioplasty (PTA) balloon, to reduce T1with only minor additional effects on T*2. With appropriate T1‐ and T*2‐weighting the vascular tree (TE <3 ms) and the device (TE ≥8 ms) could be selectively imaged (TR <20 ms). Potentially, both images could be simultaneously updated in the subsecond range. Whereas a visualization of thin structures like guidewires was found to require pulse‐sequence optimization, a successful visualization of a PTA balloon in a swine aorta in vivo was possible with standard sequences. Magn Reson Med 43:645–648, 2000. © 2000 Wiley‐Liss, Inc.

A visualization principle for MR-guided vascular interventions based on the concerted use of two contrast agents is introduced. The first contrast agent, consisting of small paramagnetic iron oxide particles, was administered intravenously to shorten T1, and even more so T *2, of the blood for extended time periods. The second agent, a monomeric gadolinium complex, was added to a solution in an interventional device, such as a percutaneous-transluminal-angioplasty (PTA) balloon, to reduce T1 with only minor additional effects on T *2. With appropriate T1- and T *2-weighting the vascular tree (TE &lt;3 ms) and the device (TE ≥8 ms) could be selectively imaged (TR &lt;20 ms). Potentially, both images could be simultaneously updated in the subsecond range. Whereas a visualization of thin structures like guidewires was found to require pulse-sequence optimization, a successful visualization of a PTA balloon in a swine aorta in vivo was possible with standard sequences. Magn Reson Med 43:645–648, 2000. © 2000 Wiley-Liss, Inc.

Abstract: Objective. To assess the shape of the posterior glenoid rim in patients with recurrent (atraumatic) posterior instability. Design and patients.CT examinations of 15 shoulders with recurrent (atraumatic) posterior instability were reviewed in masked fashion with regard to abnormalities of the glenoid shape, specifically of its posterior rim. The glenoid version was also assessed. The findings were compared with the findings in 15 shoulders with recurrent anterior shoulder instability and 15 shoulders without instability. For all patients, surgical correlation was available. Results.Fourteen of the 15 (93%) shoulders with recurrent (atraumatic) posterior shoulder instability had a deficiency of the posteroinferior glenoid rim. In patients with recurrent anterior instability or stable shoulders such deficiencies were less common (60% and 73%, respectively). The craniocaudal length of the deficiencies was largest in patients with posterior instability. When a posteroinferior deficiency with a craniocaudal length of 12 mm or more was defined as abnormal, sensitivity and specificity for diagnosing recurrent (atraumatic) posterior instability were 86.7% and 83.3%, respectively. There was a statistically significant difference in glenoid version between shoulders with posterior instability and stable shoulders (P=0.01). Conclusion.Recurrent (atraumatic) posterior shoulder instability should be considered in patients with a bony deficiency of the posteroinferior glenoid rim with a craniocaudal length of more than 12 mm.

The diagnostic utility of contrast‐enhanced three‐dimensional magnetic resonance angiography (3D MRA) was retrospectively evaluated in 24 patients with Leriche syndrome. 3D MRA was performed either of the abdomen alone (n= 6), the abdomen and chest (n= 2), the abdomen and lower extremities (n= 12), or of all stations (n= 4). MRA image sets were evaluated regarding the location of the aortic occlusion, the presence of concomitant occlusive disease affecting the renal and visceral arteries, the type and extent of collateralization, and the level of the most proximal graftable arterial segments. Intravenous digital subtraction angiography was available for correlation in two patients, while surgical correlation was possible in 14 patients. MRA permitted classification of the level of aortic occlusion as juxtarenal (n= 8), infrarenal, and cranial to the origin of the inferior mesenteric artery (IMA; n= 11), and infrarenal but caudad to the IMA (n= 5). Extraanatomical grafts were displayed to similar advantage as collateral parietal and visceral pathways. Contrast‐enhanced 3D MRA thus appears to be well suited for assessment of patients with suspected Leriche syndrome. J. Magn. Reson. Imaging 2000;11:401–410. © 2000 Wiley‐Liss, Inc.

The diagnostic utility of contrast-enhanced three-dimensional magnetic resonance angiography (3D MRA) was retrospectively evaluated in 24 patients with Leriche syndrome. 3D MRA was performed either of the abdomen alone (n = 6), the abdomen and chest (n = 2), the abdomen and lower extremities (n = 12), or of all stations (n = 4). MRA image sets were evaluated regarding the location of the aortic occlusion, the presence of concomitant occlusive disease affecting the renal and visceral arteries, the type and extent of collateralization, and the level of the most proximal graftable arterial segments. Intravenous digital subtraction angiography was available for correlation in two patients, while surgical correlation was possible in 14 patients. MRA permitted classification of the level of aortic occlusion as juxtarenal (n = 8), infrarenal, and cranial to the origin of the inferior mesenteric artery (IMA; n = 11), and infrarenal but caudad to the IMA (n = 5). Extraanatomical grafts were displayed to similar advantage as collateral parietal and visceral pathways. Contrast-enhanced 3D MRA thus appears to be well suited for assessment of patients with suspected Leriche syndrome. J. Magn. Reson. Imaging 2000;11:401–410. © 2000 Wiley-Liss, Inc.

Evaluation of the feasibility of virtual magnetic resonance (MR) arthroscopy was performed on 10 patients referred for MR arthrography of the shoulder, the elbow, or the knee. A fast spoiled contrast‐enhanced three‐dimensional gradient‐echo sequence was combined with image postprocessing to render arthroscopic views. Virtual MR arthroscopy was successfully demonstrated in all 10 joints. Determination of added diagnostic benefit will require further study. J. Magn. Reson. Imaging 1999;9:757–760. © 1999 Wiley‐Liss, Inc.

Evaluation of the feasibility of virtual magnetic resonance (MR) arthroscopy was performed on 10 patients referred for MR arthrography of the shoulder, the elbow, or the knee. A fast spoiled contrast-enhanced three-dimensional gradient-echo sequence was combined with image postprocessing to render arthroscopic views. Virtual MR arthroscopy was successfully demonstrated in all 10 joints. Determination of added diagnostic benefit will require further study. J. Magn. Reson. Imaging 1999;9:757–760. © 1999 Wiley-Liss, Inc.

Abstract.: The purpose of this study was to evaluate interactive MR-guided joint puncture with intra-articular application of contrast agent. MR-guided arthrography of the shoulder joint was successfully performed in three patients using an interactive guidance system implemented in an open-configuration MR system. Visualization of the needle pathway and contrast inflow was comparable to that with conventional X-ray fluoroscopy. The position of the intra-articular needle tip was accurately confirmed and subsequent MR arthrography was diagnostic in all cases.

Abstract: Pain affecting the foot and ankle is a common complaint frequently attributable to inflammatory joint diseases. Although conventional radiography is regarded as the initial step in the diagnostic investigation, MR imaging may contribute to further evaluation of these patients due to the direct visualization of the inflammatory soft tissue formed in the disease and its effects on bone, cartilage and para-articular structures. The high spatial resolution of MR imaging combined with tissue characterization often allows initial detection of inflammatory joint abnormalities at a stage that precedes radiographic evaluation. The typical MR appearance of certain inflammatory joint disorders may be helpful in narrowing the wide differential diagnosis. Furthermore, MR imaging can be used for an exact assessment of the extent of the disorder as well as its complications. Accurate diagnostic information can guide the clinician in further diagnostic tests and implementation of proper therapeutic treatment.

Abstract: Objective. To test the agreement between MR imaging and CT in the assessment of osteoarthritis of the lumbar facet joints, and thus to provide data about the need for an additional CT scan in the presence of an MR examination. Design and patients. Using a four-point scale, two musculoskeletal radiologists independently graded the severity of osteoarthritis of 308 lumbar facet joints on axial T2-weighted and on sagittal T1- and T2-weighted turbo-spin-echo images and separately on the corresponding axial CT scans. Kappa statistics and percentage agreement were calculated. Results. The weighted kappa coefficients for MR imaging versus CT were 0.61 and 0.49 for readers 1 and 2, respectively. The weighted kappa coefficients for interobserver agreement were 0.41 for MR imaging and 0.60 for CT, respectively. There was agreement within one grade between MR and CT images in 95% of cases for reader 1, and in 97% of cases for reader 2. Conclusion. With regard to osteoarthritis of the lumbar facet joints there is moderate to good agreement between MR imaging and CT. When differences of one grade are disregarded agreement is even excellent. Therefore, in the presence of an MR examination CT is not required for the assessment of facet joint degeneration.

Purpose:To describe the three-dimensional magnetic resonance angiography (3D MRA) imaging appearance of the pulmonary arteries following administration of a superparamagnetic iron oxide blood pool agent to human volunteers, and to demonstrate in an animal model (pigs) how this technique can be used to detect pulmonary parenchymal hemorrhage.

A magnetic resonance image (MRI)‐based method to determine the colonic transit time is described. It is based on the oral ingestion of a single dose of 4 ml Gd‐DOTA following an overnight fast and the subsequent acquisition of fast three‐dimensional (3D) gradient‐echo sequences under apnea conditions. The technique was successfully evaluated in three healthy volunteers. Transit of the contrast agent through the small and large intestines was easily followed. Thus, MRI‐based colonic transit time determinations are feasible. J. Magn. Reson. Imaging 1999;10:474–476. © 1999 Wiley‐Liss, Inc.

A magnetic resonance image (MRI)-based method to determine the colonic transit time is described. It is based on the oral ingestion of a single dose of 4 ml Gd-DOTA following an overnight fast and the subsequent acquisition of fast three-dimensional (3D) gradient-echo sequences under apnea conditions. The technique was successfully evaluated in three healthy volunteers. Transit of the contrast agent through the small and large intestines was easily followed. Thus, MRI-based colonic transit time determinations are feasible. J. Magn. Reson. Imaging 1999;10:474–476. © 1999 Wiley-Liss, Inc.

Oxidized regenerated cellulose is widely used as a bioabsorbable topical hemostatic agent. Postoperative visualization of this material through routine chest imaging, such as conventional radiography, computer tomography (CT), magnetic resonance imaging as well as sonography, may prove difficult and, to our knowledge, is not described in the literature. We describe a case where the mediastinal packing with Surgicel™ Nu-Knit™ after a mitral valve repair procedure led to a delayed obstruction of the superior vena cava, necessitating a re-thoracotomy and curettage of the hemostatic material. The hemostatic agent was not prospectively interpreted as the cause of a severe upper inflow restriction, despite repeated imaging. Retrospectively, the hemostatic material as a cause of the upper inflow obstruction could have been identified earlier if its presence would have been known to the radiologist. We strongly recommend that the surgeon inform the radiologist that such materials were used to improve the diagnostic yield of CT interpretation.

Weishaupt D, Zanetti M, Tanner A, Gerber C, Hodler J. Lesions of the reflection pulley of the long biceps tendon MR arthrographic findings. Invest Radiol 1999;34463–469.