Axial T2-weighted Magnetic Resonance Imaging Research Articles

Relationship between lung area at ultrasound examination and lung volume assessment with magnetic resonance imaging in isolated congenital diaphragmatic hernia

To prospectively examine the relationship between contralateral lung area measured by two-dimensional (2D) ultrasound examination and contralateral and total fetal lung volume (FLV) estimated by magnetic resonance imaging (MRI) in the assessment of fetuses with congenital diaphragmatic hernia (CDH). Sixty-six fetuses with isolated CDH were entered in this prospective study. Contralateral fetal lung area was measured by 2D ultrasonography using the longest axis method. Ipsilateral, contralateral and total FLV were measured using multiplanar axial T2-weighted MRI. Regression analysis was used to determine the significance of associations between contralateral lung area and contralateral and total FLV, and the predicted total FLV was subsequently calculated using the regression equation. Univariate regression analysis was used to investigate the effect on the proportionate difference between the predicted and the observed total FLV of gestational age, proportionate volume of ipsilateral vs. total FLV, side of CDH, intrathoracic herniation of the liver and intratracheal presence of a balloon. The 66 fetuses underwent a total of 191 paired 2D ultrasound and MRI examinations at a median gestational age of 30 (range, 18-38) weeks. It was possible to visualize and measure the contralateral lung area by 2D ultrasound, as well as both the ipsilateral and contralateral lung volumes by MRI, in all instances. There was a significant association between contralateral lung area and contralateral lung volume (r = 0.86; P < 0.001) and with total FLV (r = 0.84; P < 0.001). Univariate regression analysis showed that the proportionate difference between the predicted and the observed total FLV was significantly associated with the proportionate volume of ipsilateral vs. total FLV but not with gestational age, side of CDH, intrathoracic herniation of the liver or intratracheal presence of the balloon. In CDH, contralateral lung area measurement by 2D ultrasound correlates well with the total FLV estimated by MRI, irrespective of gestational age, liver herniation or side of herniation. Inconsistencies between the two measurements are attributable to the contribution of the ipsilateral lung to the total lung volume.

AJR Teaching File: Infertility in a Young Woman

Radiologic Description An oblique axial T2-weighted MR image (Fig. 1) through the horizontal long axis of the uterus shows a muscular septum arising from the fundus and extending into the body region; the overlying junctional zone is continuous over the lateral walls of the uterus. The outer contour of the fundus is flattened, whereas a normal uterine fundus is convex on the outer aspect. The left ovary seen in this image is unremarkable. The right ovary, seen better on a different image (not shown), is also normal in appearance.

Prevalence and diagnostic significance of fluid–fluid levels in soft-tissue neoplasms

To report the prevalence of fluid-fluid levels (FFLs) in soft-tissue tumours as demonstrated by magnetic resonance imaging (MRI) and the potential diagnostic relevance of this finding. A retrospective analysis was performed of 726 consecutive patients (361 women, 365 men, mean age 47.6 years+/-20.1 SD) presenting with a soft-tissue mass over a 7-year period. All subjects underwent MRI and final diagnosis was based on biopsy/surgical resection, or clinical follow-up and characteristic imaging findings. The patients were divided according to the presence or absence of FFLs on T2-weighted (T2W) axial MRI and histological diagnosis (non-neoplastic, neoplastic benign, neoplastic malignant). Cases with FFLs were sub-categorized depending upon the proportion of tumour containing FFLs: <1/3, 1/3-2/3 and >2/3, in order to determine whether the proportion of FFLs was useful for differential diagnosis. Twenty-four of the 726 (3.3%: confidence interval 2.1-4.9%) soft-tissue masses contained FFLs. One of the 24 (4.1%) was non-neoplastic (one ganglion), 12 (50.0%) were benign neoplasms (nine haemangiomas, two schwannomas, one hamartoma) and 11 (45.9%) were malignant neoplasms (one leiomyosarcoma, one liposarcoma, one malignant fibrous histocytoma, one mxyofibrosarcoma, two primitive neuroectodermal tumours, two synovial sarcomas, one spindle cell sarcoma, and two sarcomas not otherwise specified). The presence of FFLs did not help to differentiate benign from malignant neoplasms. Of the 12 benign neoplasms, 66.7% contained over two-thirds FFLs, the majority of which were haemangiomas. Of the 10 malignant neoplasms, all contained less than two-thirds FFLs: 20% had less than one-third, 80% had one to two-thirds FFLs. The prevalence of FFLs in soft-tissue tumours referred to a specialist orthopaedic oncology unit is 3.3%. However, the presence of FFLs does not reliably distinguish benign from malignant neoplasms, although all lesions with more than two-thirds FFLs were benign.

Axial Signs and Magnetic Resonance Imaging Correlates in Parkinson's Disease

Age-related brain changes may contribute to axial features in Parkinson's disease (PD). To determine if ventricular volume and white matter high signal changes (WMC) are related to motor signs in PD and controls independent of age. Patients were rated with the Unified Parkinson's Disease Rating Scale (subscore A: tremor, rigidity, bradykinesia, and facial expression; subscore B: speech and axial impairment). Steps and time taken to walk 9.144 meters were measured. Total ventricular volume (TVV) and intracranial volume (ICV) were measured on T1-weighted MRI using manual tracing software. WMC were rated on axial T2-weighted, dual-echo or FLAIR MR images using a visual scale. TVV (cm3) (PD: 36.48 +/- 15.93; controls: 32.16 +/- 14.20, p = 0.21) and WMC did not differ between groups (PD: 3.7 +/- 4.2; controls: 3.2 +/- 3.1, p = 0.55). Age correlated positively with ICV-corrected TVV and WMC in PD (cTVV: r = 0.48, p = 0.003; WMC: r = 0.42, p = 0.01) and controls (cTVV: r = 0.31, p = 0.04; WMC: r = 0.44, p = 0.003). Subscore B (r = 0.42, p = 0.01) but not subscore A (r = 0.25, p = 0.14) correlated with cTVV in PD. Steps and walking time correlated with cTVV and WMC in PD; cadence correlated with cTVV and steps with WMC in controls. Age-adjustment eliminated correlations. Subscore B, but not subscore A correlated positively with ventricular volume in PD, though this association was accounted for by age. Age-related brain change super-imposed on PD may contribute to axial features.

A dangerous development

A38-year-oldwoman,para1, underwent cesarean section at 41 weeks’ gestation. Persistent vaginal blood loss required intravenous pharmacologic management. Twentyminutes later, uterine atony persisted, as did the hemorrhaging.Uterine devascularizationwas carried out by bilateral ligation of uterine, round ligament, and utero-ovarian arteries, but that proved inadequate. Surgery was completed 15 minutes later with uterine compression suturing (B-Lynch technique). After an estimated total blood loss of at least 1700 mL, the bleeding stopped. The patient recovered with transfusions and was discharged on day 7. However, 6 weeks after that, she presented with signs and symptoms of endometritis. Despite a 2-week course of intravenous antibiotics, she remained septic. Pelvic magnetic resonance imaging (MRI) confirmed pyometra in a voluminous, ischemic uterus (Figure). A hysterectomywas performed, and the patient’s condition rapidly improved. Pelvic axial T2-weighted magnetic resonance imaging confirmed the diagnosis and determined subsequent treatment.

“Just Another Headache”

A 55-year-old woman with a 35-year history of migraine headaches had a follow-up visit with her neurologist. Her headaches had been preceded by scintillating scotomas, but she noted increasing visual scotomas, especially in the right field of vision. She was not very concerned, as she stated that it was “just another headache.” Neurologic examination including visual field testing by confrontation was normal. However, magnetic resonance imaging of the brain showed a large pituitary macroadenoma (Figure). She underwent successful transsphenoidal excision with no residual complications. Figure (a) Sagittal and (b) axial postcontrast T1-weighted magnetic resonance images of the brain showing a large elliptical avidly enhancing mass measuring 3.5 × 2.9 cm filling the sella turcica and the suprasellar cistern and compressing the optic ... A history of rapidly increasing headache frequency, lack of coordination, localized neurologic signs, or subjective numbness or tingling has been found to be associated with significantly increased odds of finding an abnormality on neuroimaging (1). Physicians should keep in mind that almost one quarter of patients with pituitary adenomas have a normal neuroophthalmological examination (2). This case stresses the importance of neuroimaging in patients with chronic headaches who present with increased headache frequency or a change in the character of their symptoms.

SIGNIFICANT TUMOR VOLUME REDUCTION OF MENINGIOMAS AFTER STEREOTACTIC RADIOTHERAPY

Stereotactic radiosurgery (SRS) is well established in the treatment of cranial base meningiomas. Fractionated stereotactic radiotherapy (SRT) offers an additional treatment option. Data for radiological regression differ, ranging from 13 to 61%. Therefore, the aims of this prospective study were to quantitatively analyze tumor volume (TV) shrinkage and to calculate determining factors. Eighty-four patients were examined under equal conditions before and after SRT. Fat-saturated axial T1-weighted contrast-enhanced magnetic resonance imaging scans with 1- to 3-mm slice thickness were used. After image fusion, TV was drawn in each slice to analyze TV shrinkage three-dimensionally by the planning system. Mean TV had shrunk by 33% at 24 months (P = 0.02) and by 36% at 36 months (P = 0.0007) after SRT. With regard to half-year intervals, TV reduction decreased continuously towards a steady state (P < 0.0001). Younger age (P = 0.001) and smaller TV (P = 0.01) are determining factors. There was no correlation between TV reduction, prescribed dose, histological classification, sex, or previous operations. Meningiomas shrink significantly after SRT. TV shrinkage declines towards a steady state, which is not yet defined. Younger age and smaller TV are determining factors. Previous operations, sex, prescribed dose, or histological subtypes do not affect TV shrinkage. Eighteen to 24 months after irradiation, when symptoms are clinically stable, is the best time for the first magnetic resonance imaging scans evaluating tumor control and shrinkage.

Postoperative Change of the Cross-Sectional Area of Back Musculature After 5 Surgical Procedures as Assessed by Magnetic Resonance Imaging

Many investigators have reported that persistent low back pain may occur after posterior surgical intervention, and studies have investigated the histologic and histochemical changes in back muscle after posterior lumbar spine surgery. The purpose of the current study is to compare the pre- and postoperative cross-sectional area of the back musculature among 5 surgical groups including anterior lumbar interbody fusion, which has no direct invasion of the back musculature, using magnetic resonance imaging, and to correlate the clinical results with the degree of atrophy. The cross-sectional area of the back musculature was measured before and after surgery in T2-weighted axial magnetic resonance images using a computer-linked digitizer. The degree of atrophy (atrophy ratio) was calculated as a ratio of the postoperative cross-sectional area to the preoperative cross-sectional area. Clinical results were evaluated using the Japanese Orthopaedic Association's scores for the management of low back pain. Atrophy of the back musculature was confirmed in each group. However, no significant difference was seen in the atrophy ratio between the groups. Back musculature atrophy occurred even in anterior lumbar interbody fusion, which does not involve any direct surgery of the back muscle. A positive correlation was noted between the atrophy ratio and operation time only in posterior surgery, especially in nonfusion surgery. In conclusion, the current study suggests that a shorter operation time may minimize back muscle injury, and shows that factors inducing back musculature atrophy include not only direct invasion of the back muscle via a posterior approach, but also postoperative external fixation.

Subdural Effusions in the Posterior Fossa Associated with Spontaneous Intracranial Hypotension

Misdiagnosis of spontaneous intracranial hypotension remains a problem, despite increasing recognition. Three patients with spontaneous intracranial hypotension presented with typical findings on lumbar puncture, magnetic resonance (MR) imaging, and radioisotope cisternography. All patients showed subdural effusions in the posterior fossa on axial T2-weighted MR imaging. Axial MR images of 112 patients with other conditions were also screened for this finding. One of three patients had typical orthostatic headache, and the other two had continuous headache. The finding of subdural effusions in the posterior fossa on axial T2-weighted MR imaging disappeared after treatment. Similar findings were found in 14 of 112 patients with other conditions. Most of the patients were over 60 years old or had dementia or previous radiation therapy. Subdural effusions in the posterior fossa can be identified by T2-weighted axial MR imaging, and are useful for the diagnosis of spontaneous intracranial hypotension and for verifying the effectiveness of treatment.

Correlation of intercondylar notch cross sections to the ACL size: a high resolution MR tomographic in vivo analysis

To correlate cross sections of the intercondylar notch to cross sections of the anterior cruciate ligament (ACL) and to analyze gender-related differences in notch and ACL morphometry with an attempt to explain the observation that a small intercondylar notch and the female gender predispose to a rupture of the ACL. High resolution MR imaging was performed on a 1.5 T magnet using a dedicated extremity-coil in ten left and ten right knee joints of 20 volunteers (10 male, 10 female, mean age 25 years) with no history of knee abnormalities. Continuous axial T2-weighted MR images perpendicular to the longitudinal axis of the ACL were acquired. Cross-sectional areas of the ACL midsubstance at the contact area to the posterior cruciate ligament were measured. For imaging and evaluation of the osseous limits of the intercondylar notch a 3D-dataset of the knee was acquired. Anterior, middle and posterior planes of the intercondylar notch were calculated and analyzed for measurement of the notch area AN and notch width index NWI. The ratio of the ACL cross-sectional area of the ACL and the cross-sectional area of the notch was defined as the ACL notch index (ANI) and used as a standardized tool for evaluation. For statistical evaluation, linear regression analysis was performed. Mean values between male and female were compared using a t test. In addition, five matched pairs of male and female volunteers of same height were analyzed. Mean cross-sectional size of the ACL at the crossing with the PCL was 54.4 +/- 20.4 mm2. Regression analysis showed a significant correlation (P < 0.05) of the ACL cross-sectional area to the notch areas on all three planes and NWI, respectively. Comparison between the sexes revealed that female participants had significantly smaller cross-sectional areas of the ACL, the notch areas, the NWI and ANI. This difference was found for both the complete study group and the matched pairs of same height. The smaller the intercondylar notch the smaller the cross-sectional area of the ACL midsubstance. In addition to the impingement of the ACL at the anterior and posterior roof of the notch, a biomechanically weaker ACL may be the reason for disposition to an ACL rupture in patients with a small intercondylar notch. Women have a thinner ACL midsubstance than men of the same height which may be one of the critical etiologic factors that predispose women to an ACL rupture.

Spontaneous resolution of a cervical synovial cyst

The natural history of synovial cysts is unpredictable, and some patients experience improvement in their symptoms or stabilization without surgery. The mechanisms behind the formation and resolution of these cysts remain controversial. We report a unique case of complete and spontaneous resolution of a C7‐T1 cervical synovial cyst. A 58-year-old woman presented with persistent tingling and numbness in the medial right forearm and hand, which had lasted for 6 months. She remembered that she had experienced pain in her shoulder and arm after she had engaged in strenuous yard work, but the pain had later subsided. The tingling was located in the medial arm, the forearm, and the medial two fingers. Intermittent neck stiffness and an aching pain in the axilla were present and bothersome. She noted that she had been experiencing difficulty in using her right arm and hand when performing tasks such as opening canned jars, buttoning and unbuttoning, and handling coins. No objective motor, sensory, or reflex alterations were detected. A tentative diagnosis of C-8 nerve root irritation or carpal tunnel syndrome was entertained. Axial T2-weighted magnetic resonance (MR) images revealed a right-sided posterolateral oval epidural lesion measuring 9 6 4 mm. The lesion was contiguous with the facet joint. The MR imaging signal intensity displayed by the lesion approximated that of cerebrospinal fluid (Fig. 1 left [arrow]). A tentative diagnosis of cervical epidural synovial cyst was made and surgery was recommended. For personal reasons, the woman did not wish to submit to surgery for 6 months. At the end of that period, an updated MR imaging study was performed. A review of the images showed that the cyst had entirely disappeared (Fig. 1 right). The patient reported that her symptoms had mostly resolved and surgery was cancelled. Based on the findings on the MR images, the diagnosis of spontaneous resolution of a cervical spinal synovial cyst was made. Contemporary evidence based on experimental and clinical observations suggests that a mechanically stressed joint induces a cascade of events (upregulation and release of angiopoietin-1, interleukins-1 and -6, platelet-derived growth factor, basic fibroblast growth factor, vascular endothelial growth factor, and substance P), 1,5 resulting in synovial hyperplasia, neovascularization, and exudation of fluid (on occasion, hemorrhagic fluid), 3 and culminating in the creation of a cyst. It appears that this process is reversible because the synovial proliferation may regress on withdrawal of mechanical stress. This seems to have happened in our patient, whose curtailment of her previous mechanical activities resulted in spontaneous resolution of the cyst. A review of the recent literature leads us to infer that injection of corticosteroid medications into the facet joint may also have helped reverse this inflammatory cascade. 2

Gastrointestinal: Giant liposarcoma

What abnormalities are seen on the computed tomography scan shown in Fig. 1? The major abnormality is a large mass on the right side of the abdomen that displaces other organs to the left and displaces the right kidney inferiorly. The mass has a slightly heterogeneous appearance with an attenuation consistent with fat. The fatty nature of the mass was supported by the loss of signal using an axial fat suppression T2-weighted magnetic resonance image. The patient was a woman, aged 72, who was admitted to hospital because of epigastric discomfort, abdominal distension and weight loss. On examination, she had a large mass in the right abdomen. A plain abdominal radiograph showed displacement of most of the bowel into the left flank. At laparotomy, the mass was well-circumscribed, pale in color and had areas of nodularity. The appearance of the resected specimen is shown in Fig. 2. The histological diagnosis was that of a well-differentiated ‘lipoma-like’ liposarcoma. Liposarcomas are soft tissue tumors that differentiate towards adipose tissue. Histologically, they can be classified in increasing order of malignancy as well-differentiated, myxoid, pleomorphic and round cell subtypes. Some specimens contain multiple histological subtypes within the same tumor. For example, one component can be an atypical lipomatous tumor while other areas have features of a cellular, non-lipogenic sarcoma (the dedifferentiated component). Although most lipomas are located in subcutaneous tissues, liposarcomas usually occur in central body sites, particularly the retroperitoneum. Computed tomography and magnetic resonance scans can predict the presence of well-differentiated liposarcomas as these tumors have an attenuation and signal intensity that is similar to that of fat. However, in contrast to lipomas, liposarcomas often show fibrous septa that are thicker and more irregular, sometimes with nodular components. Well-differentiated ‘lipoma-like’ liposarcomas can recur locally if incompletely excised but do not metastasize. Contributed by

Lower Extremity Muscle Morphology in Young Athletes: An MRI-Based Analysis

This study was conducted to describe lower extremity muscle morphology (volume and peak cross-sectional area (CSA)) in young athletes and compare these with previously reported values. A second aim was to determine if muscle morphological values differ significantly between sides, implying that unilateral measurements cannot represent both limbs accurately. Axial spin-echo T1-weighted magnetic resonance (MR) images were obtained between the ankle mortise and iliac crest in 10 athletes (age 18.8 +/- 3.7 yr). Subsequently, each subject's three-dimensional anatomy was digitally reconstructed. Muscle volume, peak CSA, and length were calculated for 13 muscles. The mean volumes and CSA for the current sample of athletes were larger than previously reported values (primarily from cadaver studies of nonathletes). The ratio of total quadriceps volume to total hamstrings volume averaged nearly 3:1 (2.9 +/- 0.2), whereas previous reports have been closer to 2:1 (2.1 +/- 0.2). The relative contribution of each muscle to the muscle group (hamstrings or quadriceps) volume was also different for these athletes. Significant differences in side-to-side muscle morphology were observed in several knee muscles (P < 0.03). Vastus medialis muscle volume was larger in the dominant leg (difference between sides: 59 +/- 25 cm3, representing 15.9 +/- 6.7% of its average volume), whereas vastus lateralis muscle volume was larger in the nondominant leg (difference: 54 +/- 47 cm3 representing 9.6 +/- 8.3% of its average). Despite this, total quadriceps volumes were similar between sides. Findings suggest that the morphology data presented in this study should be used instead of data from cadavers when studying young athletic people. These data should improve the accuracy of biomechanical modeling in the athletic population.

HYPERTROPHY OF LIGAMENTUM FLAVUM IN LUMBAR SPINAL STENOSIS ASSOCIATED WITH INCREASED PROTEINASE INHIBITOR CONCENTRATION

Background: It is well known that age-related fibrosis, or decreases in the elastin-to-collagen ratio of the ligamentum flavum, along with hypertrophy of the ligamentum flavum, are associated with lumbar spinal stenosis. However, the molecular mechanism by which this fibrosis and hypertrophy develop is unknown. Tissue inhibitors of matrix metalloproteinase (TIMPs) are proteinase inhibitors that suppress extracellular matrix degradation. Elevated TIMP-1 and TIMP-2 expression has been implicated in various fibrotic diseases of the liver, kidney, lung, and heart. These TIMPs can also induce cellular proliferation and inhibit apoptosis in a wide range of cell types. These findings led us to postulate that TIMP-1 and TIMP-2 might also be associated with hypertrophy and fibrosis of the ligamentum flavum in lumbar spinal stenosis. Methods: We quantified and localized TIMP expression in ligamentum flavum tissues that had been obtained during surgery from thirty patients with spinal stenosis and from thirty gender-matched control patients with disc herniation. The thickness of the ligamentum flavum at the level of the facet joint was measured on axial T1-weighted magnetic resonance images. In addition, we examined ligamentum flavum tissues for the expression of markers of cellular proliferation and apoptosis. Results: The ligamentum flavum was significantly thicker in the patients with spinal stenosis (mean, 5.68 mm) than in the patients with disc herniation (mean, 2.70 mm) (p < 0.001). The concentration of TIMP-2 in the ligamentum flavum was significantly higher in the patients with spinal stenosis (mean, 12.62 ng/mL) than in those with disc herniation (mean, 8.85 ng/mL) (p = 0.028). TIMP-1 and TIMP-2 were detected in the cytoplasm of ligamentum flavum fibroblasts. TIMP-1 and TIMP-2 concentrations were associated with hypertrophy of the ligamentum flavum (p = 0.015 and p = 0.003, respectively). None of the samples from the patients with stenosis had evidence of proliferation of ligamentum flavum fibroblasts. The expression of markers for apoptosis was significantly higher in the patients with spinal stenosis (58.8%) than in those with disc herniation (26.6%) (p < 0.001). Conclusions: Increased TIMP expression has been implicated in fibrosis and hypertrophy of the extracellular matrix of several organs. Our results suggest that increased expression of TIMP-2 in ligamentum flavum fibroblasts is associated with fibrosis and hypertrophy of the ligamentum flavum in patients with spinal stenosis. Clinical Relevance: Gaining insights into the molecular pathogenesis of hypertrophy and fibrosis of the ligamentum flavum may eventually result in new therapeutic and potentially noninvasive alternatives to the treatment of spinal stenosis.

Expandable and rigid endorectal coils for prostate MRI: Impact on prostate distortion and rigid image registration

Endorectal coils (ERCs) are used for acquiring high spatial resolution magnetic resonance (MR) images of the human prostate. The goal of this study is to determine the impact of an expandable versus a rigid ERC on changes in the location and deformation of the prostate gland and subsequently on registering prostate images acquired with and without an ERC. Sagittal and axial T2 weighted MR images were acquired from 25 patients receiving a combined MR imaging/MR spectroscopic imaging staging exam for prostate cancer. Within the same exam, images were acquired using an external pelvic phased array coil both alone and in combination with either an expandable ERC (MedRad, Pittsburgh, PA) or a rigid ERC (USA Instruments, Aurora, OH). Rotations, translations and deformations caused by the ERC were measured and compared. The ability to register images acquired with and without the ERC using a manual rigid-body registration was assessed using a similarity index (SI). Both ERCs caused the prostate to tilt anteriorly with an average tilt of 18.5 degrees (17.4 +/- 9.9 and 19.5 +/- 11.3 degrees, mean +/- standard deviation, for expandable and rigid ERC, respectively). However, the expandable coil caused a significantly larger distortion of the prostate as compared to the rigid coil; compressing the prostate in the anterior/posterior direction by 4.1 +/- 3.0 mm vs 1.2 +/- 2.2 mm (14.5% vs 4.8%) (p < 0.0001), and widening the prostate in the right/left direction by 3.8 +/- 3.7 mm vs 1.5 +/- 3.1 mm (8.3% vs 3.4%) (p = 0.004). Additionally, the ability to manually align prostate images acquired with and without ERC was significantly (p < 0.0001) better for the rigid coil (SI = 0.941 +/- 0.008 vs 0.899 +/- 0.033, for the rigid and expandable coils, respectively). In conclusion, the manual rigid-body alignment of prostate MR images acquired with and without the ERC can be improved through the use of a rigid ERC.

Distribution of mesorectal lymph nodes in rectal cancer: in vivo MR imaging compared with histopathological examination. Initial observations

The aim of this work was to determine the distribution of mesorectal lymph nodes using T2-weighted magnetic resonance (MR) imaging compared with histopathological findings in patients with rectal carcinoma. Sixteen patients with rectal carcinoma undergoing primary surgery without pre-operative neoadjuvant treatment were evaluated using 3-mm axial T2-weighted MR imaging. The position of each visible mesorectal node on imaging was localised by measuring its minimum distance from the mesorectal fascia (d(m)), its minimum distance from the rectal wall (d(r)) and its distance from the distal tumour margin (d(v)). Independent assessment of d(m), d(r) and d(v) was made at histopathological examination. Eighty-five mesorectal nodes on in vivo MR imaging were matched to histopathological findings. On imaging, 67/85 mesorectal nodes were found at the level of the tumour and 84/85 were identified at or within 5 cm proximal to the tumour. Only one out of 85 nodes was seen below the inferior tumour margin. The mean difference of d(m) and d(r) obtained on in vivo MR imaging and histopathological examination was 0.7 mm (95% confidence interval, CI, -0.12 to 1.42 mm) and -1.1 mm (95% CI -2.29 to 0.14 mm), respectively. Almost all mesorectal nodes visible on MR imaging were found at the level of tumour or within 5 cm proximal to the tumour. This has implications for the planning of MR imaging and the level of mesorectal transection at surgery.

Doença de Wilson: diagnóstico clínico e sinais das "faces do panda" à ressonância magnética. Relato de caso

A 25 year-old man was admitted with polymorph symptomatology resembling basal ganglia disease associated with psychiatric manifestations. The patient had been treated with pericyazine. The drug was stopped but the symptomatology did not improve. The diagnosis of Wilson's disease was established through ophthalmologic examination with slit-lamp that revealed the Kayser-Fleischer ring and laboratory abnormalities showing a low serum ceruloplasmin level and increased urinary copper excretion. T2-weighted axial magnetic resonance imaging demonstrated the " face of panda signs" in the midbrain and pons.

See-Saw Nystagmus as the Presenting Sign in Multiple Sclerosis

Although see-saw nystagmus has been reported in multiple sclerosis (MS) (1), there is no previous report of a patient presenting with this finding. A 33-year-old woman reported a 2-day history of oscillopsia. She had no other neurologic or systemic symptoms. On examination, the eyes were aligned with full ductions. The patient had characteristic pendular see-saw nystagmus that increased on left gaze. The velocity of the nystagmus was equal in both directions. The OD ascended and intorted, whereas the OS descended and extorted; then the OD descended and extorted, whereas the OS ascended and intorted. Otherwise, the ophthalmologic and neurologic examination was unremarkable. Total blood count, erythrocyte sedimentation rate, glucose, urea, electrolytes, and a collagen vascular disease profile were normal. Lumbar puncture revealed a normal opening pressure and cerebrospinal fluid formula, but isoelectric focusing showed three positive IgG oligoclonal bands; none was detected from a simultaneous serum sample. Brain magnetic resonance imaging showed a linear area of signal change in white matter adjacent to the body of left lateral ventricle (Fig. 1A) and in the deep white matter of the left frontal lobe (Fig. 1B). The combination of clinical, cerebrospinal fluid, and imaging findings suggested a diagnosis of multiple sclerosis.FIG. 1: A. Axial T2-weighted magnetic resonance imaging shows linear high signal in the white matter adjacent to the body of the left lateral ventricle (arrow). B. Coronal FLAIR magnetic resonance imaging shows high signal in the deep white matter of the left frontal lobe (arrow).The exact mechanism of see-saw nystagmus is still not known. Its frequent association with chiasmal and parasellar lesions initially led to speculation that see-saw nystagmus was related to a disturbance in visual input. Recent evidence suggests that see-saw nystagmus is caused by dysfunction of the rostral brainstem (2). A disturbance in the interstitial nucleus of Cajal, a small collection of neurons located adjacent to medial longitudinal fasciculus in the midbrain tegmentum, is often implicated (2). Soupramanien Sandramouli, FRCS, FRCOphth Hani T. Benamer, MRCP, PhD Mark Mantle, MRCP, FRCR Randhir Chavan, MS Wolverhampton and Midland Counties Eye Infirmary and Departments of Neurology and Radiology; New Cross Hospital; Wolverhampton, England; E-mail: [email protected]

Septic Arthritis of a Lumbar Facet Joint Associated with Epidural and Paraspinal Abscess

CASE REPORT A 59-year-old woman presented to our clinic two days after experiencing an onset of severe low back pain. There was no prior trauma or other known causal factor. The initial medical examination revealed no neurological abnormalities except for tenderness in her right lumbar region and a positive right Kemp sign. The patient had not developed a fever. Despite taking anti-inflammatory drugs, her low back pain continued. She was admitted 2 days after her initial visit. She had no history of spinal injections or history of diabetes mellitus. Her blood test showed that the inflammatory signs were high, the leukocyte count was 12.200/mm3 (normal range: 4.5008.500/mm3), the erythrocyte sedimentation rate was 84 mm/hr (normal: 3-15 mm/hr) and the C-reactive protein was 5.3 mg/dL (normal: 0.6 mg/dL). Plain radiographs showed no abnormal lumbar vertebrae or facet joint. A T1-weighted sagittal magnetic resonance imaging (MRI) revealed a cystic lesion on the posterior side of the spinal canal at the L2-L3 level (Figure 1). The cystic lesion showed high-signal intensity on T2-weighted axial MRI and it was observed in the epidural and paraspinal regions, communicating with the right L2-L3 facet joint (Figure 2). T1-weighted gadolinium-enhanced contrast was also noted with this lesion. There was no evidence of infection in the vertebral body or disk (Figure 3). Computed tomography scans showed swollen right paraspinal muscles, but no clear damage of the facet joint was observed. The patient’s temperature remained normal, but her C-reactive protein level increased to as high as 19.5 mg/dL 4 days after admission, and she was diagnosed as having septic arthritis of the lumbar facet joint associated with epidural and paraspinal abscess. After intravenous piperacillin sodium administration, the C-reactive protein level temporarily decreased, but her pain worsened. Three weeks later, she still had a fever that reached 38°C. Although no blood cultures showed growth, after continuous intravenous administration of sulbactam sodium/cefoperazon sodium, cefmetazole sodium, and imipenem/cilastatin sodium, her pain became intolerable; therefore, irrigation and debridement were performed 35 days after initial admission to our hospital. The L1-L3 was approached posteriorly and an abcess was noted under the multifidus muscle. The necrotic muscle was removed. The articular capsule and cartilage of the right L2L3 facet joint were debrided. An L1-L3 laminectomy was performed to drain the epidural abscess. Intraoperative cultures revealed no growth. After surgery, the low back pain resolved, and the patient did not report any recurrence at 18-month final follow-up.

Magnetic Resonance Imaging of Suspected Cervicocranial Arterial Dissections

The authors propose that the optimal screening protocol for evaluation of suspected cervicocranial arterial dissections is magnetic resonance imaging (MRI) that includes three components: 1) contrast-enhanced three-dimensional time-of-flight magnetic resonance angiography (MRA) through the superior mediastinum, neck, and skull base; 2) three-dimensional multiple overlapping thin-section acquisition MRA of the skull base and Circle of Willis region; and 3) axial non-contrast, non-fat-suppressed T1-weighted, fat-suppressed T1-weighted, and T2-weighted spin-echo MRI from the level of the aortic arch through the level of the circle of Willis. MRA permits visualization of vascular luminal narrowing or obliteration, which can suggest vascular dissection but can also be caused by congenital variation, dysplasia, intraluminal thrombus, vasospasm, or extramural compression by tumor. By directly visualizing the blood vessel wall, axial T1-weighted and T2-weighted spin-echo MRI can identify the intramural hemorrhage of vascular dissection. This protocol is designed to maximize the sensitivity of a noninvasive technique and may eliminate the need for conventional endovascular angiography.