Dynamic magnetic resonance imaging of the female pelvis: the relationship with the Pelvic Organ Prolapse quantification staging system

PURPOSE: Magnetic resonance imaging (MRI) was performed to determine anatomical correlations with respect to physical examination using the Pelvic Organ Prolapse (POP) staging system. In addition, the standard POP staging system was analyzed to obtain normative data and determine any risk factors for prolapse. MATERIALS AND METHODS: A total of 52 continent women 19 to 67 years old participated in our study. Pelvic MRI was performed at 1.5 Tesla. The vagina, bladder and rectum were opacified. Subjects performed pelvic floor contraction, relaxation and straining maneuvers for T1-weighted imaging. One-way analysis of variance, Fisher's exact test and multinomial logistic regression were used to analyze the data. RESULTS: POP stage is quantified from 0 to IV. Stage was 0 to II in 56%, 27% and 17% of cases. POP stage was not significantly influenced by the number of cesarean sections (p = 0.64) or smoking (p = 0.91) but the number of vaginal deliveries significantly correlated with stage. Women with 1 vaginal delivery were at increased risk for a stage I condition (p = 0.018), whereas those with more than 1 were at increased risk for stage II (p = 0.013). On MRI stages 0 versus I or II differed significantly in regard to bladder descent (p = 0.01 and <0.0001, respectively), while stages 0 versus I differed in regard to levator angle (p = 0.007). No significant staging differences were observed in regard to the posterior urethrovesical angle or stages I versus II with respect to all 3 MRI measurements. CONCLUSIONS: MRI appears to detect anatomically measurable changes in POP stage 0 versus other stages in regard to bladder descent and the levator angle and yet it is not sensitive enough to detect differences in stages I and II. It is not unusual for continent women to have a moderate degree of pelvic prolapse and previous vaginal delivery appears to increase this risk.     

Static magnetic resonance imaging of the pelvic floor muscle morphology in women with stress urinary incontinence and pelvic prolapse

In a study, the magnetic resonance imaging (MRI) findings of 69 women were analyzed to define the typical MRI appearance of the pelvic floor musculature in healthy subjects (n = 20) and women with urinary incontinence (UI) and/or genitourinary prolapse (GP) (n = 49). The following parameters were determined: thickness and signal intensity of the levator muscles on each side, distance between the urethra and symphysis, diameter of the proximal urethra, and thickness and configuration of the anterior vaginal wall. These parameters were correlated with the patients' age and parity, urodynamic parameters, and the clinical assessment of the pelvic floor. In contrast to healthy subjects, the frequent findings in women with UI and/or GP are higher signal intensity of the levator muscles (p < 0.05) and loss of the hammock-like configuration of the vagina (p < 0.01). On static MRI, the morphometry of the levator musculature identified no findings typical of either UI or GP. Analysis of MRI combined with patients' parity suggests that the severity of damage to the pelvic floor at delivery is determined by the traumatic event as such and not by the number of deliveries. Urethral diameter, distance of the symphysis to the urethra, and vaginal wall thickness cannot distinguish between controls and women with UI and/or GP. Urodynamic and functional clinical parameters do not correlate with the changes in the pelvic floor musculature demonstrated by static MRI. Although morphological changes in UI and/or GP can be demonstrated by MRI, they can be assigned a pathogenic role only if clinical symptoms are present. Neurourol. Urodynam. 17:579–589, 1998. © 1998 Wiley-Liss, Inc.     

Giant bladder diverticulum due to previous bullet injury: Findings of gadolinium-enhanced magnetic resonance imaging

Non-obstructive acquired giant bladder diverticulum is rare. An 84-year-old man presented with difficulty in urination. Radiological examinations including pelvic magnetic resonance imaging, urethrocystography and urethrocystoscopy demonstrated a giant bladder diverticulum with normal infravesical urinary tract. The patient had a past history of gunshot bladder injury and underwent surgical removal of the bullet. The giant bladder diverticulum was thought to be associated with the injury or the operation.     

Role of magnetic resonance imaging in tumor staging and follow-up for bladder cancer

Urothelial carcinoma of the bladder is a common urologic malignancy. Complex factors, such as local stage, tumor grade, biologic potential, and various conditions, can affect the treatment strategy for bladder cancer. However, the local stage—in particular, the presence or absence of muscle invasion—significantly influences decisions regarding treatment strategy. The role of cystoscopy for screening, diagnosis, and transurethral resection cannot be overlooked. The importance of local staging with magnetic resonance imaging is increasing; magnetic resonance imaging of the bladder is considered a useful staging modality. Moreover, a radiologic reporting system for evaluating and scoring muscle invasion of bladder cancer was recently released. This system is based on multiparametric magnetic resonance imaging and is also expected to be feasible for post-treatment follow-up of bladder cancer. In this review, we discuss the role of magnetic resonance imaging in the local staging of urothelial carcinoma of the urinary bladder and post-treatment imaging. In addition, several technical aspects for obtaining appropriate quality magnetic resonance images of the bladder will be discussed.     

磁共振弥散加权成像在诊断膀胱肿瘤恶性程度中的价值

目的:探讨磁共振弥散加权成像(diffusion weighted imaging,DWI)对膀胱肿瘤的诊断价值。方法:对36例膀胱肿瘤患者进行常规膀胱磁共振平扫检查及DWI检查,选取病灶感兴趣区测出膀胱肿瘤病灶区域大小,拟合出表观扩散系数(ADC)图,并在ADC图上直接测量不同b值(b=1 200、1 500s/mm2)及其膀胱肿瘤病灶的平均ADC值,进行量化分析。随后患者在1周内行经尿道膀胱肿瘤电切术,部分患者行根治性膀胱切除术,术中切除组织送病理检查。结果:36例患者中,b值为1 500、1 200s/mm2。在同一b值下,膀胱恶性肿瘤组的平均ADC值低于良性肿瘤组,分别为748.12±93.60、1 190.88±86.47,803.40±103.91、1 266.93±89.15(P0.05);膀胱高级别乳头状尿路上皮癌组的平均ADC值明显低于低级别乳头状尿路上皮癌组,分别为651.15±24.82、817.39±51.71,699.54±24.13、877.57±24.13(P0.05)。结论:DWI及ADC值在诊断膀胱肿瘤恶性程度中具有一定的价值。     

Correlation between clinical features and magnetic resonance imaging findings in lumbar disc prolapse

Background:

Lumbar disc prolapse is one of the common causes of low back pain seen in the working population. There are contradictorty reports regarding the clinical significance of various magnetic resonance imaging (MRI) findings observed in these patients. The study was conducted to correlate the abnormalities observed on MRI and clinical features of lumbar disc prolapse.

Materials and Methods:

119 clinically diagnosed patients with lumbar disc prolapse were included in the study. Clinical evaluation included pain distribution, neurological symptoms and signs. MR evaluation included grades of disc degeneration, type of herniation, neural foramen compromise, nerve root compression, and miscellaneous findings. These MRI findings were tested for inter- and intraobserver variability. The MRI findings were then correlated with clinical symptoms and the level of disc prolapse as well as neurological signs and symptoms. Statistical analysis included the Kappa coefficient, Odd’s ratio, and logistic regression analysis.

Results:

There were no significant inter- or intraobserver variations for most of MRI findings (Kappa value more than 0.5) except for type of disc herniation which showed a interobserver variation of 0.46 (Kappa value). The clinical level of pain distribution correlated well with the MRI level (Kappa 0.8), but not all disc bulges produced symptoms. Central bulges and disc protrusions with thecal sac compression were mostly asymptomatic, while centrolateral protrusions and extrusions with neural foramen compromise correlated well with the dermatomal distribution of pain. Root compression observed in MRI did not produce neurological symptoms or deficits in all patients but when deficits were present, they correlated well with the presence of root compression in MRI. Multiple level disc herniations with foramen compromise were strongly associated with the presence of neurological signs.

Conclusions:

The presence of centrolateral protrusion or extrusion with gross foramen compromise correlates with clinical signs and symptoms very well, while central bulges and disc protrusions correlate poorly with clinical signs and symptoms. The presence of neural foramen compromise is more important in determining the clinical signs and symptoms while type of disc herniation (bulge, protrusion, or extrusion) correlates poorly with clinical signs and symptoms.     

Role of multiparametric magnetic resonance imaging in the diagnosis and staging of urinary bladder cancer

ObjectivesTo assess the role of multiparametric magnetic resonance imaging (mp-MRI) in the diagnosis and staging of urinary bladder cancer (BC).Materials and methodsFifty patients diagnosed with bladder masses underwent mp-MRI study. The results of 3 image sets were analyzed and compared with the histopathological results as a reference standard: T2-weighted image (T2WI) plus dynamic contrast-enhanced (DCE), T2WI plus diffusion-weighted images (DWI), and mp-MRI, including T2WI plus DWI and DCE. The diagnostic accuracy of mp-MRI was evaluated using receiver operating characteristic curve analysis.ResultsThe accuracy of T2WI plus DCE for detecting muscle invasion of BC was 79.5% with a fair agreement with histopathological examination (κ = 0.59); this percentage increased up to 88.6% using T2WI plus DWI, with good agreement with histopathological examination (κ = 0.74), whereas mp-MRI had the highest overall accuracy (95.4%) and excellent agreement with histopathological data (κ = 0.83). Multiparametric MRI can differentiate between low- and high-grade bladder tumors with a high sensitivity and specificity of 93.3% and 98.3%, respectively.ConclusionsMultiparametric MRI is an acceptable method for the preoperative detection and accurate staging of BC, with reasonable accuracy in differentiating between low- and high-grade BC.     

The acute effect of magnetic stimulation of the pelvic floor on involuntary detrusor activity during natural filling and overactive bladder symptoms

OBJECTIVE: To evaluate the effect of magnetic stimulation of the pelvic floor (MSPF) on involuntary detrusor activity observed during natural filling, and on the overactive bladder symptom complex. PATIENTS AND METHODS: Eighteen women with detrusor overactivity on conventional cystometry underwent ambulatory urodynamic monitoring over two filling cycles. Fluid intake was standardized, provocative manoeuvres applied at regular intervals and symptoms documented contemporaneously. During the second filling cycle MSPF was delivered whenever the detrusor pressure increased by > 5 cmH2O. The women were subsequently treated with MSPF for 6 weeks; their lower urinary tract symptoms were assessed before and after treatment. RESULTS: Comparing the second (stimulated) cycle with the first (unstimulated) cycle, cystometric capacity was higher (373 vs 224 mL, P < 0.03). and involuntary detrusor activity of shorter duration (370 vs 427 s, P < 0.82) and lower amplitude (53 vs 63 cmH2O, P < or = 0.05). All women tolerated the procedure comfortably, but nine found it too time-consuming and withdrew. In the nine women who completed treatment there was no consistent change in overactive bladder symptoms. CONCLUSIONS: In this pilot study, MSPF during natural filling was associated with a decrease in the amplitude of involuntary detrusor contractions and a significant increase in cystometric capacity. However, MSPF had a variable effect on sensations of urgency, both acutely and after treatment, and currently there is no evidence to suggest that MSPF has an enduring effect on symptoms of the overactive bladder.     

Kinetic magnetic resonance imaging analysis of lumbar segmental mobility in patients without significant spondylosis

Purpose

The purpose of this study was to examine lumbar segmental mobility using kinetic magnetic resonance imaging (MRI) in patients with minimal lumbar spondylosis.

Methods

Mid-sagittal images of patients who underwent weight-bearing, multi-position kinetic MRI for symptomatic low back pain or radiculopathy were reviewed. Only patients with a Pfirrmann grade of I or II, indicating minimal disc disease, in all lumbar discs from L1–2 to L5–S1 were included for further analysis. Translational and angular motion was measured at each motion segment.

Results

The mean translational motion of the lumbar spine at each level was 1.38 mm at L1–L2, 1.41 mm at L2–L3, 1.14 mm at L3–L4, 1.10 mm at L4–L5 and 1.01 mm at L5–S1. Translational motion at L1–L2 and L2–L3 was significantly greater than L3–4, L4–L5 and L5–S1 levels (P < 0.007). The mean angular motion at each level was 7.34° at L1–L2, 8.56° at L2–L3, 8.34° at L3–L4, 8.87° at L4–L5, and 5.87° at L5–S1. The L5–S1 segment had significantly less angular motion when compared to all other levels (P < 0.006). The mean percentage contribution of each level to the total angular mobility of the lumbar spine was highest at L2–L3 (22.45 %) and least at L5/S1 (14.71 %) (P < 0.001).

Conclusion

In the current study, we evaluated lumbar segmental mobility in patients without significant degenerative disc disease and found that translational motion was greatest in the proximal lumbar levels whereas angular motion was similar in the mid-lumbar levels but decreased at L1–L2 and L5–S1.     

Identification of thoracic intervertebral spaces by means of surface anatomy: a magnetic resonance imaging study

BACKGROUND: Successful thoracic epidural analgesia depends on the sensory blockage of specific dermatomes following appropriate placement of the epidural catheter. This study aimed to ascertain how accurately anaesthesiologists identify thoracic intervertebral spaces, and whether counting from the prominent vertebra is easier than using the iliac crest as an anatomical landmark. METHODS: Five anaesthesiologists attempted to locate one out of five consecutive intervertebral spaces (Th7-Th8 to Th11-Th12) on patients referred for magnetic resonance imaging of the vertebral column. The intended thoracic interspace and the counting reference point (C7-Th1 or L3-L4) were marked with oil capsules. The body mass index, gender and position of the patient were recorded. The exact capsule positions were determined by a radiologist after the study. RESULTS: In 92 patients, 26.7% of the thoracic interspaces were correctly identified. The counting reference point was the only variable studied with a significant influence on error. The accuracy increased when the iliac crest was used as an anatomical landmark rather than the prominent vertebra (odds ratio, 0.29). The majority (76.4%) of all the incorrectly placed capsules were found cephalad to the intended level. CONCLUSION: We recommend that the caudal of two to three possible interspaces should be used when placing an epidural catheter in the thoracic spine. Because of the inaccurate localization of the thoracic intervertebral spaces, documentation should state the site of puncture as being in the upper or lower thoracic spine instead of claiming to be in an exact interspace.