Preinvasive and invasive cervical cancer: an ex vivo proton magic angle spinning magnetic resonance spectroscopy study.

The aim of this study was to obtain (1)H MR spectra using magic angle spinning (MAS) techniques from punch biopsies (<20 mg) of preinvasive and invasive cervical disease and to correlate the spectral profiles with sample classification on the basis of histopathology. Tissue samples were obtained at colposcopic examination, during local treatment of cervical intraepithelial neoplasia (CIN) or at hysterectomy. (1)H MAS MRS was performed at 25 degrees C while spinning the sample at 4.5 kHz. After measurement, the tissue was immersed in formalin and the pathology determined. Histological examination after (1)H MAS MRS defined 27 samples with squamous cell carcinoma (SCC), 12 with CIN and 39 with only normal tissue. The standardized integrals of the lipid, choline and creatine regions of the spectra were significantly higher in SCC than in normal or CIN tissue. There was no obvious difference in the standardized integral of the region 4.15-3.5 ppm. The acyl fatty acid side-chain length was longer or less unsaturated in SCC than in normal tissue. Normal tissue from patients with SCC showed significantly higher triglycerides than normal tissue from patients with benign uterine disease but significantly lower triglycerides than SCC tissue. (1)H MAS MRS of the uterine cervix ex vivo may be used to differentiate non-invasive from invasive cervical lesions, increase interpretation of in vivo MRS and provide insights into tumor biology.

1H magnetic resonance spectroscopy of invasive cervical cancer: an in vivo study with ex vivo corroboration.

The objective of this study was to establish in vivo (1)H-magnetic resonance (MR) spectroscopic appearances of cervical cancer using an endovaginal receiver coil and corroborate findings with magic angle spinning (MAS) MR spectroscopy of tissue samples. Fifty-three women (14 controls and 39 with cervical cancer) underwent endovaginal coil MR imaging at 1.5 T with T(1)- and T(2)-weighted scans sagittal and transverse to the cervix. Localized (1)H MR spectra (PRESS technique, TR 1600 ms, TE 135 ms) were accumulated in all controls and 29 cancer patients whose tumour filled > 50% of a single 3.4 cm(3) voxel. Peaks from triglyceride-CH(2) and -CH(3) were defined as present and in-phase (with the choline resonance), present but out-of-phase, or not present. Peak areas of choline-containing compounds were standardized to the area of unsuppressed tissue water resonance. Comparisons in observed resonances between groups were made using Fisher's exact test (qualitative data) and a t-test (quantitative data). Biopsies from these women analysed using MAS-MR spectroscopy and normalized to the intensity of an external standard of silicone rubber were similarly compared. Adequate water suppression permitted spectral analysis in 11 controls and 27 cancer patients. In-phase triglyceride-CH(2) resonances (1.3 ppm) were observed in 74% of tumours but in no control women (p < 0.001). No differences were observed in the presence of a 2 ppm resonance, choline-containing compounds or creatine in cancer compared with control women. However, ex vivo analysis showed significant differences not only in -CH(2), but also in -CH(3), a 2 ppm resonance, choline-containing compounds and creatine between tissues from control women and cancer tissue (p < 0.001, = 0.001, = 0.036, < 0.001 and = 0.004 respectively). On in vivo (1)H-MR spectroscopy, the presence of positive triglyceride-CH(2) resonances can be used to detect and confirm the presence of cervical cancer. However, technical improvements are required before routine clinical use.

Magic angle effects in MR neurography.

BACKGROUND AND PURPOSE: Magic angle effects are well recognized in MR imaging of tendons and ligaments, but have received virtually no attention in MR neurography. We investigated the hypothesis that signal intensity from peripheral nerves is increased when the nerve's orientation to the constant magnetic induction field (B(0)) approaches 55 degrees (the magic angle). METHODS: Ten volunteers were examined with their peripheral nerves at different orientations to B(0) to detect any changes in signal intensity and provide data to estimate T2. Two patients with rheumatoid arthritis also had their median nerves examined at 0 degrees and 55 degrees. RESULTS: When examined with a short TI inversion-recovery sequence with different TEs, the median nerve showed a 46-175% increase in signal intensity between 0 degrees and 55 degrees and an increase in mean T2 from 47.2 to 65.8 msec. When examined in 5 degrees to 10 degrees increments from 0 degrees to 90 degrees, the median nerve signal intensity changed in a manner consistent with the magic angle effect. No significant change was observed in skeletal muscle. Ulnar and sciatic nerves also showed changes in signal intensity depending on their orientation to B(0). Components of the brachial plexus were orientated at about 55 degrees to B(0) and showed a higher signal intensity than that of nerves in the upper arm that were nearly parallel to B(0). A reduction in the change in signal intensity in the median nerve with orientation was observed in the two patients with rheumatoid arthritis. CONCLUSION: Signal intensity of peripheral nerves changes with orientation to B(0). This is probably the result of the magic angle effect from the highly ordered, linearly orientated collagen within them. Differences in signal intensity with orientation may simulate disease and be a source of diagnostic confusion.

(1)H magnetic resonance spectroscopy of preinvasive and invasive cervical cancer: in vivo-ex vivo profiles and effect of tumor load.

PURPOSE: To compare in vivo (1)H magnetic resonance (MR) spectra of preinvasive and invasive cervical lesions with ex vivo magic angle spinning (MAS) spectra of intact biopsies from the same subjects and to establish the effects of tumor load in the tissue sampled on the findings. MATERIALS AND METHODS: A total of 51 subjects (nine with normal cervix, 10 with cervical intraepithelial neoplasia [CIN], and 32 with cervical cancer) underwent endovaginal MR at 1.5 T. Single-voxel (3.4 cm(3)) (1)H MR spectra were acquired and voxel tumor load was calculated (tumor volume within voxel as a percentage of voxel volume). Resonances from triglycerides -CH(2) and -CH(3) and choline-containing compounds (Cho) were correlated with voxel tumor load. Biopsies analyzed by (1)H MAS-MR spectroscopy (MRS) had metabolite levels correlated with tumor load in the sample at histology. RESULTS: In vivo studies detected Cho in normal, CIN, and cancer patients with no significant differences in levels (P = 0.93); levels were independent of voxel tumor load. Triglyceride -CH(2) and -CH(3) signals in-phase with Cho were present in 77% and 29%, respectively, of cancer subjects (but not in normal women or those with CIN), but did not correlate with voxel tumor load. Ex vivo cancer biopsies showed levels of triglycerides -CH(2) and -CH(3) and of Cho that were significantly greater than in normal or CIN biopsies (P < 0.05); levels were independent of the tumor load in the sample. The presence of -CH(2) in vivo predicted the presence of cancer with a sensitivity and specificity of 77.4% and 93.8% respectively, positive (PPV) and negative (NPV) predictive values were 96% and 68.2%; for -CH(2) ex vivo, sensitivity was 100%; specificity, 69%; PPV, 82%; and NPV, 100%. CONCLUSION: Elevated lipid levels are detected by MRS in vivo and ex vivo in cervical cancer and are independent of tumor load in the volume of tissue sampled.

Esophageal cancer staging with endoscopic MR imaging: pilot study.

The authors defined esophageal anatomy and evaluated esophageal cancer staging in a pilot group by comparing endoscopic magnetic resonance (MR) imaging results with pathologic and endoscopic ultrasonographic (US) results when available. A porcine esophagus, one volunteer, and 23 patients suspected of having esophageal cancer were imaged at 0.5 T. MR imaging was successful in 21 patients. Eight of these patients underwent esophagectomy (one after chemotherapy, which invalidated comparison with MR imaging; another did not undergo lymphadenectomy) and one underwent laparoscopy and nodal staging only; eight underwent US. When verified with pathologic staging, endoscopic MR imaging was accurate in six of seven patients (T stage) and five of six patients (N stage; nodal areas too obscured by artifact for comparison in one case). MR imaging and US results concurred in seven of eight (T stage) and five of eight (N stage) patients. No complications were observed. Endoscopic MR imaging is safe and probably comparable to endoscopic US, but with a tendency to overstage the disease.

An inductively-coupled, detachable receiver coil system for use with magnetic resonance compatible endoscopes.

PURPOSE: To construct an inductively-coupled receiver coil system for use with a magnetic resonance (MR) compatible endoscope, and to evaluate its use in a pilot group of patients with esophageal cancer. MATERIALS AND METHODS: An inductively-coupled coil system, comprising a saddle geometry cylindrical receiver coil fitted as a sleeve around the endoscope tip and a pick-up coil housed within a channel of an MR-compatible endoscope, was designed and developed for use at 0.5 T. Twenty-three patients with esophageal cancer were recruited for MR endoscopy. In 17 cases, the endoscopic coil system was used in conjunction with an external surface coil in order to obtain information from the surrounding mediastinum. The examination took 40-50 minutes. RESULTS: MR imaging using the inductively-coupled endoscopic coil was successful in 21 cases (one failed intubation and one artifact from unrelated external source). Image artifact was largely due to respiration and global patient motion in sedated individuals undergoing endoscopy. CONCLUSION: Inductively-coupled coil systems may be used with endoscopes to allow improved safety through increased patient-system isolation and detachability of coils and electronics for repair or replacement with coils tuned for different frequencies.

Female urinary genuine stress incontinence: anatomic considerations at MR imaging of the paravaginal fascia and urethra initial observations.

PURPOSE: To compare, on high-spatial-resolution magnetic resonance (MR) images, the presence and distribution of the paravaginal fascia in continent women and in those with genuine stress incontinence (GSI) to establish its role in the pathophysiology of GSI. MATERIALS AND METHODS: Eleven continent reference subjects and 10 GSI patients underwent MR imaging with a specifically designed endovaginal receiver coil. A urinary continence questionnaire and urogynecologic clinical examination had been completed. GSI was diagnosed with urodynamic tests. Paravaginal fascial tissue distribution was determined, and the paravaginal fascial volume (PFV) anteriorly associated with the urethra was measured. Retropubic urethral length (UL) in the supine position at rest was compared with its total length and expressed as a percentage ratio. Comparisons of urethral PFV and retropubic UL between reference subjects and the GSI patients were performed by means of two-sample t tests with unequal variances because data were parametric by means of the Shapiro-Francia W' test for normal data. RESULTS: The paravaginal fascia (connective tissue that contained venous plexus) was a consistent MR imaging feature in all women. Mean urethral PFV was 5.3 cm(3) +/- 0.6 (SD) in reference subjects compared with 3.5 cm(3) +/- 2.0 in GSI patients (P =.017). The ratio of the retropubic UL to its total length was 82.6% +/- 7.4 in reference subjects compared with 57.4% +/- 9.8 in GSI patients (P <.001). There was a weak correlation between urethral PFV and retropubic UL (r = 0.46). CONCLUSION: There is a significant association between urethral PFV and continence status. GSI patients have a reduced urethral PFV, and greater than 40% of their urethral length lies below the pubis in the supine position at rest. However, the effects of age and hormonal status on urethral PFV remain to be evaluated.

Uterine arterial embolization for leiomyomas: perfusion and volume changes at MR imaging and relation to clinical outcome.

PURPOSE: To monitor changes in perfusion and volume of uterus and leiomyomas after bilateral uterine artery embolization (UAE) and to correlate immediate perfusion changes with subsequent reduction in leiomyoma volume and clinical outcome. MATERIALS AND METHODS: Eleven consecutive women underwent magnetic resonance (MR) imaging before UAE, immediately after, and at 1 and 4 months. Reduction in maximal enhancement above baseline at 90 seconds (ME(90)) after injection of the dominant leiomyoma immediately after embolization was correlated with its volume reduction at 4 months and with clinical response at 12 months. RESULTS: Forty-five leiomyomas were noted (mean, four per patient). Myometrium enhanced briskly (ME(90) of 110%), with a reduction in ME(90) to 26% immediately after embolization. Initial leiomyoma ME(90) was lower (P <.001), but it suppressed to baseline levels immediately after embolization. At 1 and 4 months, myometrial perfusion returned to normal, but leiomyoma perfusion remained suppressed (P <.001). Immediate reduction in leiomyoma ME(90) correlated with clinical response (Spearman rho = 0.64). Leiomyomas initially high in SI on T2-weighted images showed significantly greater volume reduction than those low in SI (P =.006). Well-perfused leiomyomas did not show greater volume reduction than those that were poorly perfused. Volume reduction did not correlate with improvement in clinical symptom score. CONCLUSION: Immediate reduction in leiomyoma perfusion after bilateral UAE correlates with clinical response, whereas leiomyomas initially high in SI on T2-weighted images indicate a likely greater volume reduction.