Cavernous sinus: correlation between anatomic and dynamic gadolinium- enhanced MR imaging findings

Dynamic magnetic resonance (MR) images were evaluated and compared with conventional T1-weighted spin-echo (SE) images obtained before and after administration of gadopentetate dimeglumine in 20 patients with normal cavernous sinuses. Starting 10 seconds after rapid injection of gadopentetate dimeglumine (0.1 mmol/kg), six to eight serial images were obtained every 30 seconds for 3-5 minutes. The venous spaces of the cavernous sinus were markedly enhanced 30 seconds after injection. Cranial nerves III and IV, V1 and VI, and V2 were seen on 75% of dynamic images each; they were seen, respectively, on 62%, 30%, and 28% of conventional postcontrast images. The medial wall was demarcated on 90% of dynamic, 15% of precontrast, and 55% of postcontrast images. A small area of connective tissue was identified within the cavernous sinus on dynamic images showing gradual enhancement. It is concluded that dynamic MR images proved useful in delineating and distinguishing abnormal tissue from normal structures.     

Hypophysitis: endocrinologic and dynamic MR findings.

PURPOSEOur purpose was to assess the worth of dynamic MR imaging in the evaluation of vascular changes of the pituitary in patients with lymphocytic hypophysitis.METHODSFive patients (four males, one female; 9 to 53 years old) with lymphocytic hypophysitis or infundibuloneurohypophysitis were studied. All patients underwent endocrinologic studies and a series of two to five MR examinations performed over a period of 8 months to 5 years, including a total of nine dynamic imaging studies.RESULTSTwo patients had panhypopituitarism and three had partial hypopituitarism. Diabetes insipidus was present in four patients. Among the five patients, the pituitary was enlarged in three, of whom two showed improvement on follow-up MR studies. Three patients had a thickened stalk, which improved on subsequent examinations. In all nine dynamic studies, the enhancement time of the whole pituitary was delayed to over 90 seconds, even though five of the nine conventional, simultaneously performed MR studies showed a normal pituitary. The peak time of posterior pituitary enhancement in the first dynamic study was also delayed in all patients (from 60 to 120 seconds). In two patients, normal early enhancement of the posterior pituitary was identified on initial studies but not on subsequent studies.CONCLUSIONDynamic MR imaging can display an abnormality of the hypophysial vasculature even if the pituitary disease is seen to regress on the conventional MR study. The delay or even the lack of early enhancement of the posterior pituitary in lymphocytic hypophysitis may be due to secondary inflammatory changes.     

Posterolateral supporting structures of the knee: findings on anatomic dissection, anatomic slices and MR images

In this article we study the ligaments and tendons of the posterolateral corner of the knee by anatomic dissection, MR-anatomic correlation, and MR imaging. The posterolateral aspect of two fresh cadaveric knee specimens was dissected. The MR-anatomic correlation was performed in three other specimens. The MR images of 122 patients were reviewed and assessed for the visualization of different posterolateral structures. Anatomic dissection and MR-anatomic correlation demonstrated the lateral collateral, fabellofibular, and arcuate ligaments, as well as the biceps and popliteus tendons. On MR images of patients the lateral collateral ligament was depicted in all cases. The fabellofibular, arcuate, and popliteofibular ligaments were visualized in 33, 25, and 38% of patients, respectively. Magnetic resonance imaging allows a detailed appreciation of the posterolateral corner of the knee.     

CT urography and MR urography

CT urography and MR urography are an evolving concept and developing technique. As the technology matures, CT urography will combine the ultimate diagnostic capabilities of intravenous urography and CT. In the near future, many intravenous urograms will be replaced by CT urography to evaluate patients with hematuria and other genitourinary conditions. MR urography currently serves as an alternative imaging technique to intravenous urography and CT urography for children and pregnant women and for patients with contraindications to iodinated contrast media.     

Sclerosing stromal tumor of the ovary: US, MR, and dynamic MR findings

The US, MR, and dynamic MR findings in four patients with sclerosing stromal tumor of the ovary are reported. US showed a tumor with multilocular cystic components and irregularly thickened septa and tumor walls or a solid tumor including several small cystic components. On T2-weighted MR images, signal intensities of the cystic components were high and those of the solid components were inhomogeneous, ranging from intermediate-high to high. Dynamic MRI demonstrated marked early enhancement of the solid components.     

Cervical spine: postmortem assessment of accident injuries--comparison of radiographic, MR imaging, anatomic, and pathologic findings.

PURPOSE: To assess the ability of postmortem radiography and magnetic resonance (MR) imaging to depict occult cervical spine injuries as compared with anatomic and pathologic findings. MATERIALS AND METHODS: The cervical spines of 10 adult accident victims underwent radiography and MR imaging, with T1-weighted, fast spin-echo T2-weighted, and four gradient-echo pulse sequences. The frozen specimens were cut into 3-mm-thick slices (sagittal plane) and photographed, and microfocus radiographs were obtained. Imaging findings were compared with the anatomic and pathologic findings. RESULTS: Eight of the 10 specimens had 28 posttraumatic lesions: three fractures (two missed at the initial MR imaging reading), 10 facet joint capsule lesions with bleeding, five soft-tissue and ligament lesions, eight disk lesions, and two spinal cord lesions. Radiography depicted one lesion (4%). Two partial ruptures of the anterior annulus fibrosus were depicted at only MR imaging. Initially, 11 of 28 lesions were detected on MR images; retrospectively, 17 of 28 lesions were correlated with anatomic findings. CONCLUSION: Soft-tissue and intervertebral disk and ligament injuries account for 89% (25 of 28) of posttraumatic cervical spine lesions detected on postmortem images. Occult lesions, including apophyseal joint injuries, were found in clinically noninjured cervical spines. MR imaging was limited in the depiction of discrete lesions when T1-weighted non-fat-saturated, fast spin-echo T2-weighted, and gradient-echo pulse sequences were used.     

MR泌尿系成像的技术和应用

目的：估价ＭＲ泌尿系成像的技术和应用价值。材料与方法：用重Ｔ２加权快速自旋回波（ＦＳＥ）序列和脂肪抑制技术作ＭＲ泌尿系成像９５例。所有图像均作最大信号强度投影（ＭＩＰ）处理。结果：９５例均清楚显示肾实质和泌尿系集合系统高质量的影像。７１例阳性，２４例阴性。阳性病种包括：肾癌７例，肾囊肿１７例，肾脓肿１例，肾盂癌４例，肾盏血块１例，肾结核７例，输尿管癌６例，输尿管结石３例，狭窄２例，非梗阻性输尿管扩张和膀胱癌各４例，前列腺病３例，以及各种先天异常等１２例。结论：ＭＲ泌尿系成像是一种很可靠的、非侵袭性的检查方法，它不用造影剂，可避免碘副反应。在形态上，它能较好地显示泌尿系的解剖结构，补充了泌尿系影像学检查方法，是技术上的一大进步。     

Primary retroperitoneal neoplasms: CT and MR imaging findings with anatomic and pathologic diagnostic clues.

Primary retroperitoneal neoplasms are a rare but diverse group of benign and malignant tumors that arise within the retroperitoneal space but outside the major organs in this space. Although computed tomography and magnetic resonance imaging can demonstrate important characteristics of these tumors, diagnosis is often challenging for radiologists. Diagnostic challenges include precise localization of the lesion, determination of the extent of invasion, and characterization of the specific pathologic type. The first step is to determine whether the tumor is located within the retroperitoneal space. Displacement of normal anatomic structures of the retroperitoneum is helpful in this regard. For tumors that are located within the retroperitoneum, the next step is to identify the organ of origin. Specific signs, including the "beak sign," the "embedded organ sign," and the "phantom (invisible) organ sign," are useful for this purpose. When there is no definite sign that suggests the organ of origin, the diagnosis of a primary retroperitoneal tumor becomes likely. Awareness of specific patterns of spread, specific tumor components, and tumor vascularity help in further narrowing the differential diagnosis. Attention to these diagnostic clues is essential in making an accurate radiologic diagnosis of primary retroperitoneal tumors and in obtaining clinically significant information. Copyright RSNA, 2003.     

Three-dimensional dynamic MR hysterosalpingography: a preliminary report

The aim of this study was to evaluate the feasibility of three-dimensional dynamic MR hysterosalpingography (3D MR HSG) for visualization of the cavum uteri and demonstration of bilateral fallopian tube patency as an alternative to conventional hysterosalpingography. Five infertile female patients underwent 3D dynamic MR HSG prior to conventional hysterosalpingography. The MR protocol consisted of axial T1-weighted spin-echo (SE), axial/coronal T2-weighted fast SE (FSE), and 3D MR angiography sequences before, during, and after injection of a diluted gadolinium solution into the cavum uteri via a balloon catheter. Positioning of the catheter was feasible in all patients. In one patient the catheter slipped out during MRI and in one patient the catheter was placed far in the cavum uteri. In three patients catheter position was optimal at the level of the cervical canal. Evaluation of pelvic anatomy, myometrium, and ovaries was possible in all patients on the basis of T1-weighted SE and T2-weighted FSE. Three-dimensional visualization of the dilated cavum uteri was possible in four patients. In these four patients 3D MR HSG also proved bilateral fallopian tube patency which was confirmed in each patient by conventional hysterosalpingography. Three-dimensional MR HSG is feasible and further research should be done to determine if this technique can evolve into an alternative technique to conventional hysterosalpingography with the advantages of no radiation and additional visualization of the uterus wall and ovaries.     

Borderline ovarian malignancy: ultrasound and fast dynamic MR findings

Ovarian tumors of borderline malignancy are low-grade malignant neoplasms, and have a rather good prognosis. They account for ≈10–20% of all ovarian tumors. Very few reports are available in literature that analyses ultrasound and MR findings in establishing the diagnosis. The purpose of this study is to describe eight cases of ovarian tumors of borderline malignancy with dynamic gadolinium-enhanced MR imaging. Comparison is made with CA 125 serum levels and ultrasound findings. Early enhancing endocystic vegetations, local cystic masses in, and (irregular) thickened walls of large multicystic tumors were important findings in borderline malignant tumors. The accuracy to detect a malignant tumor of borderline malignancy with CA 125, ultrasound and MRI in these eight cases was 50, 63 and 75%, respectively. MRI is a valuable imaging modality to characterize adnexal tumors and might play a role in preoperative evaluation of borderline malignancies.     

磁共振泌尿系造影的相关技术和临床应用探讨

目的评价磁共振泌尿系造影（ＭＲＵ）的成像技术对揭示尿路梗阻部位及原因的价值和限度，并推广应用半傅立叶转换快速自旋回波序列（ＦＡＳＥ）行ＭＲＵ检查的技术方法。方法１８例尿路梗阻、８例非尿路梗阻性疾患及５例健康志愿者，应用ＦＡＳＥ技术行ＭＲＵ检查。无尿路梗阻者１３例检查前口服速尿２０ｍｇ。所有图像后处理均采用最大信号强度投影（ＭＩＰ）技术。结果尿路梗阻病人均能显示梗阻部位和程度，诊断敏感率达１００％，诊断正确率为８３％（１５／１８）。口服速尿增强ＭＲＵ提供了良好的肾脏形态和尿路解剖结构。结论ＭＲＵ是一种方便快捷的技术，可提供高分辨尿路图像     

Dynamic contrast-enhanced MR urography in the evaluation of pediatric hydronephrosis: Part 2, anatomic and functional assessment of uteropelvic junction obstruction

OBJECTIVE: The purpose of our study was to retrospectively review our experience using MR urography in the diagnosis of ureteropelvic junction (UPJ) obstruction in children. MATERIALS AND METHODS: Sixty-one studies were performed in 50 children with hydronephrosis but without hydroureter. Anatomic criteria assessed included degree of hydronephrosis, morphology of the renal pelvis, atrophy of medulla, swirling contrast material, fluid levels, and the presence of fetal folds and crossing vessels. Functional criteria included renal transit time, differential renal function, and time-intensity curves when available. RESULTS: Thirty-one kidneys were classified as obstructed, 15 as equivocal, and 15 as nonobstructed. Obstructed systems had more marked hydronephrosis, more extensive medullary atrophy, more fluid levels, and more swirling contrast material. Fetal folds were seen in only the equivocal and nonobstructed groups. Crossing vessels were seen in all groups. Obstructed systems also showed greater functional derangement, decreased split renal function, and abnormal time-intensity curves. CONCLUSION: MR urography provides both excellent anatomic and functional information in children with UPJ obstruction in a single test that does not use ionizing radiation. MR urography may lead to greater understanding of the pathophysiology of UPJ obstruction.     

MR urography findings of a duplicated ectopic ureter in an adult man

In this report we present the imaging findings in an adult male with a duplicated ectopic ureter which inserted into the prostatic urethra. The appearances at excretory urography, US, CT, and MR urography are described together with the potential pitfalls of the imaging techniques. Both US and MR urography accurately image the collecting system from the kidney to the point of distal ureteral insertion, and in our patient, MR urography provided similar information to US. Received: 20 July 1999; Revised: 21 December 1999; Accepted: 24 December 1999     

Time-resolved dynamic contrast-enhanced MR urography for the evaluation of ureteral peristalsis: initial experience

Purpose

To determine the feasibility of time‐resolved dynamic contrast‐enhanced magnetic resonance urography (MRU) for the evaluation of ureteral peristalsis using a data‐sharing 3D gradient echo sequence with spiral k‐space filling.

Materials and Methods

Eight patients (M = 3, F = 5, mean 48.1 years) were referred for MRU for the evaluation for renal mass (n = 3), hematuria (n = 2), urinary tract tuberculosis (n = 1), postoperative bladder cancer (n = 1), and postoperative ureteric reimplantation (n = 1). Dynamic MRU was performed for 120 seconds at 1.5T after intravenous furosemide and gadolinium administration using an oblique sagittal, time‐resolved T1 3D gradient echo sequence with 1 second effective temporal resolution. Study quality was assessed based on artifacts and extent of ureteric visualization. Frequency of peristalsis from the renal pelvis to urinary bladder was evaluated for each subject.

Results

A total of 16 ureters were examined. Image quality was good in four ureters, satisfactory in 11 ureters, and poor in one ureter. Mean peristaltic frequency was 3.5 waves per minute (range, 2.5–6.5 waves/minute) in normal ureters (n =11). Five ureters were considered abnormal (one urinary tract tuberculosis and four postsurgical ureters), and all had decreased or no peristalsis (0–1.5 waves per minute).

Conclusion

MRU using a time‐resolved, data‐sharing 3D contrast‐enhanced technique is able to demonstrate ureteral peristalsis and permits quantification of ureteral peristaltic frequency. J. Magn. Reson. Imaging 2008;28:1293–1298. © 2008 Wiley‐Liss, Inc.     

Functional and morphologic evaluation of congenital urinary tract dilatation by using combined static-dynamic MR urography: findings in kidneys with a single collecting system

PURPOSE: To assess combined static-dynamic magnetic resonance (MR) urography in the evaluation of congenital urinary tract dilatation in infants and children. MATERIALS AND METHODS: Sixty-two patients with urinary tract dilatation underwent prospective examination with combined static-dynamic MR urography. A combination examination involved use of a static T2-weighted three-dimensional inversion-recovery fast spin-echo sequence and a dynamic T1-weighted two-dimensional fast field-echo sequence with gadopentetate dimeglumine-DTPA and furosemide application. Twelve additional patients underwent examination with only static MR urography. Thus, both image quality and morphologic features were assessed in 74 patients with the use of MR urography. The results were compared with those of ultrasonography and, when available, conventional urography or surgery. In 62 patients, the dynamic sequence was used to calculate split renal function from renograms generated from parenchymal regions of interest and to assess urinary excretion from whole-kidney renograms. Results were compared with those of diuretic renal scintigraphy (DRS) for split function (Spearman rank correlation coefficient) and urinary excretion (kappa coefficient). RESULTS: Stenoses at the ureteropelvic (n = 33) and ureterovesical (n = 31) junctions and within the ureter (n = 3) and nonstenotic dilatation (n = 23) were clearly depicted, while the normal urinary tract (n = 51) was depicted in its entirety in 47 of 51 examinations. Image quality was considered good or excellent in 95% of the kidney-ureter units. For split renal function, dynamic MR urography and DRS showed significant correlation (r = 0.92, P <.001). For urinary excretion, MR urography and DRS showed strong agreement (kappa = 0.67), with concordant classification of urinary excretion in 59 (81%) of 73 abnormal kidney-ureter units and in all 47 (100%) normal kidney-ureter units. CONCLUSION: Combined static-dynamic MR urography provides high-quality depiction of the urinary tract in infants and children, while allowing accurate determination of single-kidney function and reliable evaluation of urinary excretion.