Staging of spinal metastasis using special techniques of magnetic resonance imaging

The diagnosis of spine metastasis is a problem of great interest which leaves many questions unanswered. In this field MR imaging plays a fundamental role, as the only technique able to directly demonstrate the changes in bone marrow tissue, bound to tumoral activity. The introduction of gradient-echo (GE) sequences has helped reduce examination time. Moreover, with the accurate choice of pulse-sequence parameters (TR, TE, flip angle) additional information is acquired which is not yielded by conventional spin-echo (SE) sequences. Our study was aimed at evaluating MR sensitivity in the different stages of bone metastatic evolution. The comparative adequacy was evaluated of combined bone scintigraphy and conventional radiology versus MR imaging in 62 patients with vertebral metastases. Time interval between bone scan and/or radiological study and MR exam ranged from 10 days to 8 months. SE and GE T1-weighted images, and SE and GE T2-weighted images on the sagittal plane were employed, and axial images; coronal images were rarely acquired. Metastases were demonstrated by MR imaging at 122 vertebral levels, versus 88 true positives of combined scintigraphy and conventional radiology. Scintigraphic false-positives were observed at 15 vertebral levels, versus 9 with radiography. GE sequences were superior to SE ones in detecting vertebral morphologic lesions and bone marrow involvement thanks to their improved resolution and sensitivity. Moreover, GE sequences demonstrated tumoral bone marrow spread and persistent tumoral activity in the follow-up of spine metastases. Our results point to GE sequences as those of choice because of their higher resolution and sensitivity, which also allow response to treatment to be evaluated.     

Staging endometrial cancer: role of magnetic resonance imaging

This review article summarizes and comments the role of magnetic resonance imaging (MRI) in the management of endometrial cancer. The MRI technique, appearance, and diagnostic criteria of endometrial carcinoma are discussed. The value of MRI in the preoperative staging of endometrial cancer is compared to alternative strategies. Contrast-enhanced MRI performs best in the pretreatment evaluation of myometrial or cervical invasion, compared to ultrasonography (US), computed tomography (CT), or nonenhanced MRI. The overall costs and accuracy are similar to those of the current methods of staging, including intraoperative gross dissection of the uterus. In addition, results of MRI might decrease the number of unnecessary lymph node dissections. J. Magn. Reson. Imaging 2001;13:850-855.     

Assessment of pelvic floor dysfunctions using dynamic magnetic resonance imaging

Purpose

The purpose of this study was to assess pelvic floor dysfunction using dynamic MRI.

Material and methods

A prospective study was carried out on 21 consecutive patients presented during February 2013 to June 2013 with pelvic pain, difficulty in defecation, constipation or organ prolapse. Pelvic floor was imaged using T2-weighted and fast imaging employing steady-state acquisition sequences. Pubococcygeal line was used as the line of reference which further allowed measurement of width and vertical descent of levator hiatus. Anorectal angle was measured to assess relaxation and contraction of puborectalis muscle. Grading of prolapse was classified as mild, moderate and severe. All data were recorded both in resting and during straining phase.

Results

A total of 21 patients were studied, with a mean age of 37.3 (9.4) years with 15 (71.4%) females and 6 (21%) males. Dynamic MR revealed cystocele and rectocele in 7 (33.3%) patients, each. Three (14.28%) patients had enteroceles and spastic pelvic syndrome, each. Only one patient (4.76%) had descending perineal syndrome. Intussusception was observed in 10 (47.6%) patients with commonest type being intra rectal seen in 7 (33.3%) patients.

Conclusion

Dynamic MRI is an ideal, non invasive technique which does not require patient preparation for evaluation of pelvic floor. It acts as one stop shop for diagnosing single or multiple pelvic compartment involvement in patients with pelvic floor dysfunction.     

Dynamic imaging of the pelvic floor using an open-configuration magnetic resonance scanner

The aims of this study were to develop a noninvasive, erect, gravity-dependent method for assessing movements of the female pelvic floor, to describe the range of movements in pelvic floor ascent and descent in asymptomatic and symptomatic women, and to quantify any differences. A total of 102 women, 28-86 years of age, 35 symptomatic and 67 asymptomatic, were included in the study. They were scanned in a sitting position in an open scanner with good vertical access using fast-gradient echo sequences fast spoiled grass (FSPGR). Measurements of the bladder base, uterocervical junction, and anorectal junction were taken in the sagittal plane. The levator ani (LA) muscle insertion was assessed in the coronal plane with the patients at rest, during maximal strain, and during maximum contraction of the pelvic floor. Premenopausal multiparous women have a significantly lower bladder base (8/0 mm above the baseline; P value = 0.009) and uterocervical junction (15.5/3.5 mm; P value = 0.03) at rest than nulliparous women, and this becomes more apparent on straining. Parity confers a more significant effect on the position and function of the pelvic floor than menopausal status. All pelvic organs are lower at rest and on straining in women with defecation difficulties (0/-24 mm; P value = 0.001). These differences are also seen when comparing women with and without urinary incontinence. Dynamic seated magnetic resonance imaging (MRI) shows that all the pelvic organs are lower at rest and on straining in multiparous women and in those with urinary incontinence than in a group of asymptomatic nulliparous volunteers. This difference is also seen in the position of the bladder base and anorectal junction during pelvic floor contraction. These findings suggest general pelvic floor weakness in women who present with symptoms in one compartment and indicate the need for evaluation of the entire pelvic floor particularly prior to surgery. J. Magn. Reson. Imaging 2001;13:923-929.     

Evaluation of recurring meniscal tears with gadolinium-enhanced magnetic resonance imaging: a randomized, prospective study

BACKGROUND: Magnetic resonance imaging has been shown to be of questionable accuracy in detecting recurrent meniscal tears after previous resection or repair. PURPOSE: To compare the accuracy of nonenhanced magnetic resonance imaging with that of intraarticular contrast-enhanced direct magnetic resonance arthrography and intravenous contrast-enhanced indirect magnetic resonance arthrography for detection of recurrent meniscal tears. STUDY DESIGN: Prospective cohort study. METHODS: Forty-one patients who had previous meniscal tears treated by resection or repair but who were experiencing recurrent knee symptoms were prospectively randomized into one of three groups: conventional magnetic resonance imaging, indirect arthrography, and direct arthrography. The interpretations of two musculoskeletal radiologists were compared with the findings of an arthroscopic procedure performed 2 to 14 weeks later. RESULTS: Conventional imaging had a sensitivity of 57.9%, specificity of 80%, and overall accuracy of 62.5%. Intravenous contrast improved the sensitivity to 90.9%, specificity to 100%, and overall accuracy to 93.8%; intraarticular contrast had a sensitivity of 91.7%, specificity of 100%, and an overall accuracy of 92.9%. CONCLUSIONS: We demonstrated an increased accuracy of intravenous or intraarticular contrast-enhanced magnetic resonance arthrography in detecting recurrent meniscal tears. Both contrast routes demonstrated similar accuracy, a finding not previously reported.     

High-resolution magnetic resonance imaging and conventional magnetic resonance imaging on a standard field-strength magnetic resonance system compared to arthroscopy in patients with suspected meniscal tears

RATIONALE AND OBJECTIVES: We sought to evaluate the diagnostic performance of high-resolution magnetic resonance imaging (MRI) and conventional MRI of the knee on a standard-field-strength MRI system compared to arthroscopic findings in patients with suspected meniscal tears. MATERIALS AND METHODS: Forty-two patients (20 women, 22 men), referred from the department of trauma surgery, with suspected medial meniscal tears and planned arthroscopy of the knee joint were included in the study. MRI was performed on a 1.0-T MRI scanner with two different protocols: (1) conventional MRI using a circular, polarized knee coil (coil diameter: 17 cm) with a sagittal dual fast spin-echo sequence (repetition time [TR]: 2500 ms; echo time [TE]: first, shortest, second, 120 ms; turbo spin echo [TSE] factor: 12; field of view: 180 mm; matrix: 256 x 512; scan percentage: 100; slice thickness: 3 mm) or (2) high-resolution MRI with a surface dual-loop coil of the medial knee compartment (temporomandibular joint, coil diameter: 8 cm) with a sagittal dual fast spin-echo sequence (TR: 2400 ms; TE: first, shortest; second, 120 ms; TSE factor: 12; field of view: 120 mm; matrix: 512 x 512; slice thickness: 2 mm). The menisci were evaluated on the basis of an adapted score (0 = normal meniscus, 1 = intrameniscal, T2-weighted hyperintense signal, 2 = discontinuity of the surface, 3 = fragmentation). Lesions that received a score of 2 or 3 were graded as meniscal tears. The MRI results were compared to the arthroscopic reports, which represented the gold standard, and the sensitivity of both protocols in detecting a meniscal tear was determined. RESULTS: Of the 42 patients included in the study, 25 (11 women and 14 men) underwent arthroscopy and all demonstrated a meniscal tear. A meniscal tear was correctly diagnosed in 76% of cases with conventional MRI and in 88% of cases with high-resolution MRI (P = .0087). CONCLUSION: High-resolution MRI, using a surface dual-loop coil and specific sequences, which can be performed on every standard-field-strength MRI scanner, is able to significantly improve diagnostic performance for the detection of a meniscal tear of the knee joint.     

Diagnostic accuracy of staging renal cell carcinomas using multidetector-row computed tomography and magnetic resonance imaging: a prospective study with histopathologic correlation

OBJECTIVE: The aim of this prospective study is to compare the diagnostic accuracy of multidetector-row computed tomography (CT) and magnetic resonance imaging (MRI) in tumor staging of renal cell carcinomas. METHODS: In a prospective study, 82 renal cell carcinomas were assessed for tumor staging before surgery using multidetector-row CT and MRI, the results of which were then correlated to histopathologic staging. Triphasic CT (noncontrast, arterial phase, and parenchymal phase) imaging was performed using multidetector-row CT with a reconstructed slice thickness of 2 mm. In MRI, a transverse T1-weighted gradient echo sequence with and without administration of Gd-DTPA, a transverse T2-weighted respiratory-gated turbo spin echo (TSE) sequence, and a coronal T1-weighted gradient echo sequence with Gd-DTPA were used. In addition, multiphasic 3-dimensional angiography after Gd-DTPA injection and a transverse T1-weighted fat-suppression sequence were performed. RESULTS: With MRI, readers 1 and 2 correctly staged 71 and 64 tumors (overall accuracy of 0.87 and 0.78, respectively) and achieved Mantel-Haenszel chi(2) values of 66 and 63 (P < 0.0001). Computed tomography allowed correct staging of 68 and 66 tumors (readers 1 and 2, overall accuracy of 0.83 and 0.80, respectively) with Mantel-Haenszel chi(2) values of 54 and 54 for CT staging (P < 0.0001). No statistically significant difference between overall accuracy was found in the chi(2) test (P > 0.15). CONCLUSION: Magnetic resonance imaging and multidetector-row CT with its multiplanar reconstruction capabilities achieve similar accuracy in tumor staging of renal cell carcinomas.     

Popliteal cysts: a reassessment using magnetic resonance imaging

The advent of magnetic resonance imaging (MRI) prompted the reevaluation of the incidence of popliteal cyst and its associated injuries. We reviewed more than 1000 consecutive MRI examinations of the knee performed on patients referred for evaluation of internal derangement. We report a 5% incidence of popliteal cyst, which is lower than has previously been determined. We believe that the reported higher incidence was due to arthrographic distention of normal, collapsed bursae. The strong association between popliteal cyst and tear of the medial meniscus is confirmed. We report for the first time to our knowledge the 13% association between popliteal cyst and complete tear of the anterior cruciate ligament.     

In vivo prostate magnetic resonance imaging and magnetic resonance spectroscopy at 3 Tesla using a transceive pelvic phased array coil: preliminary results

Magnetic resonance (MR) systems operating at 3 Telsa (T) and above have demonstrated considerable potential in human studies, offering improved signal-to-noise ratio and spectral resolution. However, because of radiofrequency limitations and concerns, and the lack of large volume body coils, most studies have been limited to the head. In this study we describe the design and construction of a transceive pelvic phased array coil with which MR images and spectra of the human prostate at 3 T have been obtained. Comparison with 1.5 T instruments with different hardware configurations is difficult; however, in a preliminary comparison the signal-to-noise ratio is improved in phantoms and humans when compared with a 1.5 T receive-only pelvic phased array coil, and high quality spectral resolution is demonstrated through the delineation of the citrate quadruplet in localized 1H prostate spectra. Higher fields offer the potential for MR prostate studies without the use of an endorectal coil.     

Preoperative magnetic resonance imaging staging of uterine cervical carcinoma: results of prospective study

OBJECTIVE: To determine the accuracy of the preoperative staging of uterine cervical cancer by magnetic resonance (MR) imaging in 115 patients in a prospective study. METHODS: A prospective study was performed in 115 patients who underwent MR imaging at 1.5 T before surgery or biopsy. Histopathologic findings were correlated with MR imaging results for all patients. RESULTS: The accuracy of preoperative tumor staging by MR imaging in the 115 patients was 77%. In terms of the evaluation of parametrial status, this study had an accuracy of 94% and a sensitivity of 38%. The accuracy and sensitivity of MR imaging for vaginal invasion were 81% and 87%, respectively. In terms of lymph node metastasis, this study had an accuracy of 97% and a sensitivity of 36%. CONCLUSION: Magnetic resonance imaging has high accuracy in the preoperative staging of uterine cervical cancer.     

Brain magnetic resonance imaging at 3 Tesla using BLADE compared with standard rectilinear data sampling

OBJECTIVES: We sought to evaluate Periodically Rotated Overlapping ParallEL Lines with Enhanced Reconstruction (PROPELLER; BLADE) data acquisition in comparison with standard k-space sampling techniques for axial and sagittal brain imaging at 3 T regarding imaging artifacts. MATERIAL AND METHODS: Forty patients who gave consent were included in a prospective comparison of standard and PROPELLER (BLADE) k-space sampling techniques. All examinations were performed at 3 T with comparison of standard T2-weighted fluid-attenuated inversion recovery (FLAIR) to PROPELLER T2-weighted FLAIR in the axial image orientation and standard T1-weighted gradient echo to PROPELLER T1-weighted FLAIR in the sagittal image orientation. Imaging protocols were matched for spatial resolution, with data evaluation performed by 2 experienced neuroradiologists. Image data were compared regarding various image artifacts and overall image quality. Reader agreement was assessed by Cohen's kappa statistics. RESULTS: PROPELLER T2-weighted axial data acquisition showed significantly less pulsation and Gibb's artifacts than the standard T2-weighted scan. Even without motion correction, the frequency of ghosting (motion) artifacts was substantially lower in the PROPELLER T2-weighted data and readers concordantly (kappa = 1) rated PROPELLER as better than or equal to the standard T2-weighted scan in the majority of cases (95%; P < 0.0001). In the comparison of sagittal T1-weighted data sets, readers showed only fair agreement (kappa = 0.24) and noted consistent wrap artifacts in PROPELLER T1-weighted FLAIR. CONCLUSION: PROPELLER (BLADE) brain magnetic resonance imaging is also applicable at 3 T. In addition to minimizing motion artifacts, the PROPELLER acquisition scheme reduces other magnetic resonance artifacts that would otherwise degrade scan quality.     

Staging papillary carcinoma of the thyroid: magnetic resonance imaging vs ultrasound of the neck

AIM: To evaluate the role of magnetic resonance imaging (MRI) for staging local disease and lymph node metastases in papillary carcinoma of the thyroid by comparing MRI with ultrasound (US) of the neck. MATERIALS AND METHODS: Fourteen patients with papillary carcinoma underwent MRI and US. The images were prospectively reviewed for (1) identification of the primary lesion; (2) presence of multifocal thyroid disease; (3) extracapsular extension; (4) invasion into the trachea, oesophagus and major vessels; and (5) presence of lymph node metastases. Correlation was made with the surgical findings. RESULTS: The site of the primary lesion was correctly identified by US in 14 of 14 (100%) and by MRI in 13 of 14 (93%) of patients. Multifocal thyroid tumour was correctly identified by US in two of two patients (100%) and by MRI in zero of two (0%). Extracapsular extension (n = 9), oesophageal invasion (n = 1) and tracheal invasion (n = 2) were identified by MRI in seven, zero, and one, and by US in six, zero and zero patients, respectively. Invasion of the major vessels was not seen. Metastatic cervical nodes were present in 19 nodal groups in 10 patients involving the internal jugular chain (n = 10), posterior triangle (n = 4) supraclavicular fossa (n = 1) and central group (n = 4). Both MRI and US failed to identify metastatic nodes in the central group but correctly identified 14 of the 15 nodal groups outside the central group. CONCLUSION: Ultrasound should be used as the first line of investigation for detecting the primary lesion, multifocal disease and cervical lymphadenopathy. In cases where the primary tumour is not surrounded by normal thyroid tissue MR imaging should be added to assess extracapsular spread, especially into the trachea.     

Staging of cervical carcinoma: accuracy of magnetic resonance imaging and computed tomography

A prospective study was undertaken to assess the ability of magnetic resonance imaging (MRI) to stage cervical carcinoma. Compared to computed tomography (CT), MRI showed a high degree of accuracy in correctly demonstrating involvement of the vagina, parametria and sidewalls, bladder, and lymph nodes but tended to overestimate disease in all of the categories studied. Large-scale studies comparing the two modalities are necessary because the most accurate staging of cervical carcinoma is crucial for selecting the best treatment protocols.     

Acute rhabdomyolysis: evaluation with magnetic resonance imaging compared with computed tomography and ultrasonography

Fifteen patients with acute rhabdomyolysis were evaluated with low field magnetic resonance (MR) imaging and the results compared with those obtained using computed tomography (CT) and ultrasonography (US). With MR imaging, abnormal muscles with areas of increased signal intensity were seen in every patient, which probably reflects increased water content or increased mobility of water molecules caused by inflammatory reaction and oedema in the injured and necrotic muscles. Computed tomography without intravenous contrast medium demonstrated abnormal muscles in most patients examined with this modality. The CT findings consisted of areas of focal hypodensity in muscles. With US, abnormal muscles were seen in less than half of the patients studied. The normal structure of striated muscle was focally disturbed and areas of both decreased and increased echogenicity were found. Magnetic resonance imaging had a higher sensitivity in the detection of abnormal muscles than CT or US (100%, 62% and 42%, respectively). The findings of all these modalities are non-specific, but together with the clinical and laboratory data they confirm the diagnosis of rhabdomyolysis. The information gained from imaging studies is useful in the assessment of the extent and distribution of rhabdomyolysis. The precise identification of affected muscle compartments by MR imaging is valuable when surgical fasciotomy is considered for treatment; the procedure can then be appropriately directed to the compartments with clearly abnormal muscles.     

Fast magnetic resonance imaging of the knee using a parallel acquisition technique (mSENSE): a prospective performance evaluation

The performance of a magnetic resonance (MR) imaging strategy that uses multiple receiver coil elements and integrated parallel imaging techniques (iPAT) in traumatic and degenerative disorders of the knee and to compare this technique with a standard MR imaging protocol was evaluated. Ninety patients with suspected internal derangements of the knee joint prospectively underwent MR imaging at 1.5 T. For signal detection, a 6-channel array coil was used. All patients were investigated with a standard imaging protocol consisting of different turbo spin-echo sequences proton density (PD), T₂-weighted turbo spin echo (TSE) with and without fat suppression) in three imaging planes. All sequences were repeated with an integrated parallel acquisition technique (iPAT) using the modified sensitivity encoding (mSENSE) algorithm with an acceleration factor of 2. Two radiologists independently evaluated and scored all images with regard to overall image quality, artefacts and pathologic findings. Agreement of the parallel ratings between readers and imaging techniques, respectively, was evaluated by means of pairwise kappa coefficients that were stratified for the area of evaluation. Agreement between the parallel readers for both the iPAT imaging and the conventional technique, respectively, as well as between imaging techniques was found encouraging with inter-observer kappa values ranging between 0.78 and 0.98 for both imaging techniques, and the inter-method kappa values ranging between 0.88 and 1.00 for both clinical readers. All pathological findings (e.g. occult fractures, meniscal and cruciate ligament tears, torn and interpositioned Hoffa’s cleft, cartilage damage) were detected by both techniques with comparable performance. The use of iPAT lead to a 48% reduction of acquisition time compared with standard technique. Parallel imaging using mSENSE proved to be an efficient and economic tool for fast musculoskeletal MR imaging of the knee joint with comparable diagnostic performance to conventional MR imaging.Karl-Friedrich Kreitner and Bernd Romaneehsen contributed equally to this work.     

Identification of occult breast lesions detected by magnetic resonance imaging with targeted ultrasound: A prospective study

Objective

To verify the capacity of targeted ultrasound (US) to identify additional lesions detected on breast magnetic resonance imaging (MRI), but occult to initial mammography, US and clinical examinations.

Methods

This prospective study included 68 additional relevant breast lesions identified on MRI of 49 patients. As an inclusion criterion, breast US and mammography were required and performed up to six months before MRI. These lesions were then subjected to targeted “second-look” US up to 2 weeks after MRI, performed by one or two radiologists with expertise on breast imaging. Lesions were evaluated according to the established Breast Imaging Report and Data System (BI-RADS) lexicon.

Results

Targeted US identified 46/68 (67.6%) lesions revealed by MRI. No significant associations were observed between US identification and the type of lesion, dimensions, morphological characteristics and enhancement pattern according to MRI findings. Targeted US identified 100% of BI-RADS category 5 lesions, 90% of category 4 lesions, and just over 50% of category 3 lesions (p < 0.05). There was significant agreement (p < 0.001) between MRI and US BI-RADS classification for all three categories.

Conclusion

Targeted US can identify a large proportion of the lesions detected by breast MRI, especially those at high risk of malignancy, when performed by a professional with experience in both breast US and MRI.