The value of spinal magnetic resonance imaging (MRI) in locating prolapses of lumbar intervertebral discs

Between 1986 and 1988 100 patients in whom MRI had been used to diagnose prolapses of lumbar intervertebral dises were admitted to the neurosurgical department of the Munich Technical University. MRI proved to be a valuable diagnostic technique, even if one has to concede certain limitations to the usefulness of the results when compared to conventional methods, particularly in such cases where clinical symptoms are not clear. Typical findings are illustrated and compared with those seen in MRI, whose relative importance is discussed.     

Prebiopsy magnetic resonance spectroscopy and imaging in the diagnosis of prostate cancer

Introduction: Existing screening investigations for the diagnosis of early prostate cancer lack specificity, resulting in a high negative biopsy rate. There is increasing interest in the use of various magnetic resonance methods for improving the yield of transrectal ultrasound‐guided biopsies of the prostate in men suspected to have prostate cancer. We review the existing status of such investigations. Methods: A literature search was carried out using the Pubmed database to identify articles related to magnetic resonance methods for diagnosing prostate cancer. References from these articles were also extracted and reviewed. Results: Recent studies have focused on prebiopsy magnetic resonance investigations using conventional magnetic resonance imaging, dynamic contrast enhanced magnetic resonance imaging, diffusion weighted magnetic resonance imaging, magnetization transfer imaging and magnetic resonance spectroscopy of the prostate. This marks a shift from the earlier strategy of carrying out postbiopsy magnetic resonance investigations. Prebiopsy magnetic resonance investigations has been useful in identifying patients who are more likely to have a biopsy positive for malignancy. Conclusions: Prebiopsy magnetic resonance investigations has a potential role in increasing specificity of screening for early prostate cancer. It has a role in the targeting of biopsy sites, avoiding unnecessary biopsies and predicting the outcome of biopsies.     

Comparison of endorectal magnetic resonance imaging, guided prostate biopsy and digital rectal examination in the preoperative anatomical localization of prostate cancer

PURPOSE: We compared the accuracy of endorectal magnetic resonance imaging (erMRI), transrectal ultrasound (TRUS) guided biopsy and digital rectal examination (DRE) for detecting the location of cancer in the prostate gland and seminal vesicles. MATERIALS AND METHODS: This is a retrospective study of 106 consecutive patients with prostate cancer who were referred for erMRI before radical prostatectomy. Step-section pathological data and erMRI were available in 90 patients, DRE data were available on 86 and individually labeled sextant core biopsies were available in 45. T1 and T2-weighted erMRI was interpreted by a single reader, who scored the likelihood of tumor on a 5-point scale in each seminal vesicle and in 12 locations in the prostate gland. MR spectroscopy data were not used for erMRI interpretation. One pathologist reviewed whole mount serial sections of radical prostatectomy specimens. The area under ROC curves was used to evaluate accuracy. RESULTS: The area under ROC curves for tumor localization was higher for erMRI than for DRE at the prostatic apex (0.72 vs 0.66), mid gland (0.80 vs 0.69) and base (0.83 vs 0.69). It was likewise higher for erMRI than for TRUS biopsy in the mid gland (0.75 vs 0.68) and base (0.81 vs 0.61) but not in the apex (0.67 vs 0.70). On mixed model analysis erMRI significantly increased the accuracy of prostate cancer localization by DRE or TRUS biopsy (each p <0.0001). CONCLUSIONS: For prostate cancer localization erMRI contributes significant incremental value to DRE or TRUS biopsy findings (each p <0.0001).     

The association between patellofemoral alignment and osteoarthritis in magnetic resonance imaging

ObjectivesOsteoarthritis (OA) is the most common joint disease in the world, becoming more prevalent with increasing age, and causes a significant burden on individuals and society. So far, several factors have been identified in association with OA of the knee joint. Age is the most crucial uncontrollable risk factor for OA. There are conflicting results regarding the relationship between patellofemoral joint orientation and OA. This study aims to elucidate the relationship between patellofemoral joint alignment and OA evidence.Material and methodsA total of 277 MRIs performed at Imam Reza Hospital during the first half of 2017 were included. Patients were divided into two groups, under 50 years old and over 50 years old. Femoral sulcus angle (SA) and depth (SD), lateral patellar displacement (LPD), tibial tubercle-trochlear groove (TTTG), lateral patellofemoral angle (LPFA), and Insall-Salvati index were measured in axial and sagittal images. The morphology of the patellofemoral articular cartilage was evaluated and the grade of joint damage was determined. P-value < 0.05 was considered as significant.ResultsSignificant correlations between SA (p-value = 0.01), SD (p-value < 0.001), Insall-Salvati index (p-value < 0.001), LPD (p-value = 0.02) values and OA in patients less than 50 years old were observed. A weak correlation was observed between SD and Insall-Salvati index values with increasing grade of articular cartilage damage (r = 0.21 and r = 0.21, respectively).ConclusionsPatellofemoral joint asymmetry in the younger people was significantly associated with joint cartilage damage and premature patellofemoral joint OA. Joint misalignment by stressing the articular cartilage causes joint cartilage changes that may be congenital or due to bone injuries such as trauma and surgery.     

Anaesthesia for magnetic resonance imaging: a survey of current practice in the UK and Ireland

The lack of information about standards for anaesthetic practice in magnetic resonance imaging is of concern, since increasing requests are being made for this service, often in units not designed for the purpose. An overview of current practice was sought by conducting a postal survey of magnetic resonance units in the UK and Ireland. Replies were received from 100 units (79%), 46 of which had an anaesthetic service provided. A wide diversity of practice and opinion on the conduct of anaesthesia in this field was evident from the replies received. The survey highlighted particular areas of concern about the personal safety of anaesthetists within such units, including exposure to magnetic fields, noise and unscavenged anaesthetic gases. The evidence for such concerns is reviewed.     

Clitoral anatomy in nulliparous, healthy, premenopausal volunteers using unenhanced magnetic resonance imaging

PURPOSE: We determined the magnetic resonance imaging (MRI) characteristics of normal clitoral anatomy. MATERIALS AND METHODS: A series of MRI studies of 10 healthy, nulliparous volunteers with no prior surgery and normal pelvic examination was studied and the key characteristics of clitoral anatomy were determined. A range of different magnetic resonance sequences was used without any contrast agent. RESULTS: The axial plane best revealed the clitoral body and its proximal continuation as the paired crura. The glans was seen more caudal than the body of the clitoris. The bulbs of the clitoris had the same signal as the rest of the clitoris in the axial plane and they related consistently to the other erectile structures. The bulbs, body and crura formed an erectile tissue cluster, namely the clitoris. In turn, the clitoris partially surrounded the urethra and vagina, forming a consistently observed tissue complex. Midline sagittal section revealed the shape of the body, although in this plane the rest of the clitoris was poorly displayed. The coronal plane revealed the relationship between the clitoral body and labia. The axial section cephalad to the clitoral body best revealed the vascular component of the neurovascular bundle to the clitoris. The fat saturation sequence particularly highlighted clitoral anatomy in healthy, premenopausal, nulliparous women. CONCLUSIONS: Normal clitoral anatomy has been clearly demonstrated using noncontrast pelvic MRI.     

MRI在诊断腰间盘脱出症中的应用及价值

自１９８７年７月到１９９１年１２月共收治１１４例腰间盘脱出症，手术治疗１１０例，其中ＭＲＩ检查确诊为腰间盘脱出症为８０例。ＭＲＩ检查与手术结果符合率占９７．５％．文章就．ＭＲＩ检查优于ＣＴ及ＭＲＩ图象区别腰间盘变性与腰间盘脱出作了阐述。     

The caudal canal in children: a study using magnetic resonance imaging

The anatomy of the caudal (sacral extradural) space was studied in 41 children, using magnetic resonance imaging. The distance from the upper margin of the sacrococcygeal membrane to the dural sac, the length of the membrane and the maximum depth of the caudal space were each measured. Age, height, weight and body surface area were recorded and, using multiple linear regression (stepwise technique), equations predicting the length of the membrane and the distance between its upper margin and the lower limit of the dural sac were obtained. Wide variability limits the clinical usefulness of these equations. In all patients, the maximum depth of the caudal space was found to be at the upper margin of the sacrococcygeal membrane. No correlation was found between this maximum depth and the age, height, weight or body surface area of the child.     

Accuracy of ultrasonography and magnetic resonance imaging in the diagnosis of non-palpable testis

BACKGROUND: Studies were needed to evaluate the accuracy of ultrasonography (US) and magnetic resonance imaging (MRI) for diagnosing non-palpable testis, and to study the clinical usefulness of US and MRI before surgical exploration. METHODS: Fifty-six patients with non-palpable testis aged 1--12 years were examined between 1993 and 2002. Forty-six patients (55 non-palpable testes) underwent US. Forty patients (47 non-palpable testes) were examined using MRI. Both US and MRI were used in 29 patients (34 non-palpable testes). We used Fisher's exact probability test to compare the results of these graphic examinations with the surgical or laparoscopic findings for the non-palpable testis. RESULTS: Ultrasonography had a sensitivity of 76%, a specificity of 100%, and an accuracy of 84% in the diagnosis of non-palpable testis, whereas MRI had a sensitivity of 86%, a specificity of 79%, and an accuracy of 85%. CONCLUSIONS: There were no statistically significant differences in the accuracy rates of US and MRI for diagnosing non-palpable testis. Laparoscopy or inguinal exploration should be performed even if these graphic examinations demonstrate the absence of a testis, because some patients with a non-palpable testis were found to be false negatives. We recommend US as the first step after clinical examination, and MRI could be performed when the US findings are negative preoperatively for a non-palpable testis.     

Real-time magnetic resonance imaging (MRI): anatomical changes during physiological voiding in men

Study Type – Diagnostic (exploratory cohort) Level of Evidence 2b What’s known on the subject? and What does the study add? Micturition cysturethrography or video urodynamics can show sequences of the micturition cycle, but are limited to show all participating structures at one. MRI is a non invasive imaging methodology to describe the anatomy of physiological voiding or voiding dysfunction. In our study we provide preliminary insight in anatomical changes in the lower urinary tract during physiological micturition in males. This imaging methodology may help detecting anatomical differences in individuals with voiding disorders. Further, we presume that the vertical contraction of the ventral prostate seem to contribute to the initiation of successful micturition, additionally to the funnelling of the bladderneck.

OBJECTIVE

• ? To investigate the interactions between the bladder, urethra, pelvic floor and the function of the prostate during ‘normal’ voiding.

PATIENTS AND METHODS

• ? In all, 16 men with no history of urinary incontinence, urgency or obstructive voiding dysfunction were enrolled. We analysed the interaction between the bladder, urethra, pelvic floor and changes in the prostate during the Valsalva manoeuvre and voiding using real‐time magnetic resonance imaging (rtMRI).
• ? The axis through the external sphincter (AES) to pubo‐coccygeal line (PC‐line) and the angle between the axis of the os pubis (AOP) and ventral prostate (VP) was measured before and at the end of voiding. Additionally, the angle between the AOP and the VP was measured during the Valsalva manoeuvre.
• ? Change of position, or contraction, of the VP was measured.

RESULTS

• ? The mean age of the men was 69.8 years and mean prostate volume 33.1 mL.
• ? Before voiding, the mean AES to PC‐line was 10.5 mm. At the end of voiding, the mean AES to PC‐line was 20 mm.
• ? The mean angle between AOP/VP was 31.6° in the storage phase and increased to a mean of 54.5° during voiding.
• ? During the Valsalva manoeuvre, the angle between the AOP/VP remained constant.
• ? There was a mean vertical contraction of the VP of 48.25 mm before voiding and a declining of the cranio‐caudal distance of the VP with a mean of 33.92 mm during voiding.

CONCLUSIONS

• ? All the men in our study showed relaxation of the pelvic floor, followed by a descent of the bladder neck. Voiding could not be initiated unless the prostate rotated around the symphysis.
• ? The study suggests that both the rotation and a vertical contraction of the prostate precede voiding.
• ? The anatomy of physiological voiding or voiding dysfunction can be investigated non‐invasively using rtMRI.

     

Differentiation between deep and superficial fibers of the lumbar multifidus by magnetic resonance imaging

The purpose of this study was to investigate the differentiation in muscle tissue characteristics and recruitment between the deep and superficial multifidus muscle by magnetic resonance imaging. The multifidus is a very complex muscle in which a superficial and deep component can be differentiated from an anatomical, biomechanical, histological and neuromotorial point of view. To date, the histological evidence is limited to low back pain patients undergoing surgery and cadavers. The multifidus muscles of 15 healthy subjects were investigated with muscle functional MRI. Images were taken under three different conditions: (1) rest, (2) activity without pain and (3) activity after experimentally induced low back muscle pain. The T2 relaxation time in rest and the shift in T2 relaxation time after activity were compared for the deep and superficial samples of the multifidus. At rest, the T2 relaxation time of the deep portion was significantly higher compared to the superficial portion. Following exercise, there was no significant difference in shift in T2 relaxation time between the deep and superficial portions, and in the pain or in the non-pain condition. In conclusion, this study demonstrates a higher T2 relaxation time in the deep portion, which supports the current assumption that the deep multifidus has a higher percentage of slow twitch fibers compared to the superficial multifidus. No differential recruitment has been found following trunk extension with and without pain induction. For further research, it would be interesting to investigate a clinical LBP population, using this non-invasive muscle functional MRI approach.     

积极监测：低风险甲状腺微小乳头状癌的一线治疗？

根据世界卫生组织标准,甲状腺乳头状癌中将直径≤10 mm的肿瘤称为甲状腺微小乳头状癌（PTMC）。随着超声的普及,PTMC的发病率逐年升高,但其对应的死亡率却变化不大。对于无淋巴结转移或远处转移的低风险PTMC患者而言,手术是否是他们的唯一选择？针对这类患者,考虑到其预后好,手术并发症影响大,国外有学者提出了一种新的非手术治疗方法-积极监测（AS）,这在国际上引发了大家的热议。本文通过对大家的争议点进行梳理,希望给临床医生的治疗决策带来更好的参考。