脑裂头蚴病的MRI诊断

目的分析、探讨脑裂头蚴病的脑部MRI征象。方法搜集经临床确诊的脑裂头蚴病15例，回顾性分析其脑部的MRI征象。结果15例脑裂头蚴病患者脑内单发或多发不对称病灶共21个，顶叶8个，额叶6个，颞叶2个，枕叶2个，基底节、小脑半球及桥脑各1个。病灶MRI表现为T1WI呈稍低信号，T2WI呈较高信号，病灶周围脑实质可见大片状水肿。增强扫描10例，病灶均显示强化，大部分呈环形、串珠状或匐行管状强化。6例MRI复查发现2例病灶强化的位置及形态有改变。结论脑裂头蚴病的脑部MRI表现具有一定的特征性，增强扫描及追踪复查至关重要。     

Unsuspected lower extremity deep venous thrombosis simulating musculoskeletal pathology

Objective The purpose of this study was to highlight the critical role that MRI may play in diagnosing unsuspected lower extremity deep venous thrombosis and to stress the importance of scrutinizing MRI studies of the lower extremity showing apparently non-specific muscle edema for any evidence of intramuscular venous thrombosis.Design and patients The imaging studies of four patients in whom deep venous thrombosis was unsuspected on clinical grounds, and first diagnosed on the basis of MRI findings, were reviewed by two musculoskeletal radiologists in consensus. In all four patients the initial clinical suspicion was within the scope of musculoskeletal injuries (gastrocnemius strain, n=3; ruptured Baker cyst, n=1), explaining the choice of MRI over ultrasound as the first diagnostic modality.Results All patients showed marked reactive edema in the surrounding soft tissues or muscles. Three patients showed MR evidence of branching rim-enhancing structures within intramuscular plexuses characteristic of venous thrombosis (gastrocnemius, n=1; sural, n=2); one patient showed a distended popliteal vein. Ultrasound was able to duplicate the MRI findings in three patients: one patient showed above-the-knee extension on ultrasound; neither of the two patients with intramuscular thrombosis demonstrated on ultrasound showed extension to the deep venous trunks.Conclusion Intramuscular venous thrombosis can present as marked edema-like muscle changes on MRI, simulating primary musculoskeletal conditions. In the absence of clinical suspicion for deep venous thrombosis, only the identification of rim-enhancing branching intramuscular tubular structures will allow the correct diagnosis to be made.     

Parasitic lesion of the insula suggesting cerebral sparganosis: case report

Cerebral sparganosis, a parasitic disease, rarely produces a chronic active inflammatory response in the brain. Clinically and radiographically the process may mimic a neoplasm. We report a 30-year-old man who underwent surgical exploration for a mass in the insular cortex. Histology revealed a densely fibrotic mass heavily infiltrated with plasma cells and lymphocytes, in which were embedded parasitic forms consistent with sparganosis. We describe the MRI appearances and pathologic features. Intracranial mass lesions secondary to sparganosis must be considered in patients with a history of travel to endemic areas, especially Asia. Received: 4 March 1999/Accepted: 11 June 1999     

MR imaging of clear cell sarcoma (malignant melanoma of the soft parts): a multicenter correlative MRI-pathology study of 21 cases and literature review

Objective. To evaluate MR imaging and pathology findings in order to define the characteristic features of clear cell sarcoma of the soft tissues (malignant melanoma of the soft parts). Design and patients. MR examinations of 21 patients with histologically proven clear cell sarcoma of the musculoskeletal system were retrospectively reviewed and assessed for shape, homogeneity, delineation, signal intensities on T1- and T2-weighted images, contrast enhancement, relationship with adjacent fascia or tendon, secondary bone involvement, and intratumoral necrosis. In 19 cases the pathology findings were available for review and for a comparative MR-pathology study. Results. On T1-weighted images, lesions were isointense (n=3), hypointense (n=7) or slightly hyperintense to muscle (n=11). Immunohistochemical examination was performed in 17 patients. All 17 specimens showed positivity for HMB-45 antibody. In nine of 11 lesions with slightly increased signal intensity on T1-weighted images, a correlative MR imaging-pathology study was possible. All nine were positive to HMB-45 antibody. Conclusions. Clear cell sarcoma of the musculoskeletal system often has a benign-looking appearance on MR images. In up to 52% of patients, this lesion with melanocytic differentiation has slightly increased signal intensity on T1-weighted images compared with muscle. As the presence of this relative higher signal intensity on T1-weighted images is rather specific for tumors displaying melanocytic differentiation, radiologists should familiarize themselves with this rare entity and include it in their differential diagnosis when confronted with a well-defined, homogeneous, strongly enhancing mass with slightly higher signal intensity compared with muscle on native T1-weighted images. Received: 18 October 1999 Revision requested: 19 November 1999 Revision received: 21 January 2000 Accepted: 25 January 2000     

Synovial hemangioma: imaging features in eight histologically proven cases,review of the literature,and differential diagnosis

Objective This study was undertaken to describe the imaging characteristics of synovial hemangioma, with the goal of improving the disappointing rate (22%) of clinical diagnosis of this condition. A review of the literature and the differential diagnosis of intra-articular lesions, including synovial osteochondromatosis and pigmented villonodular synovitis, are also presented.Patients The subjects of the study were 8 patients (4 males, 4 females; age range: 5–47 years; mean age: 19 years) with histologically confirmed synovial hemangioma involving the knee (n=7) or wrist (n=1). We retrospectively examined the imaging studies performed in these patients, including plain radiography (n=8), magnetic resonance imaging (MRI; n=4), angiography (n=3), arthrography (n=2), and contrast-enhanced computed tomography (CT; n=2).Results Plain radiographs showed a soft tissue density suggesting either joint effusion or a mass in all patients. Phleboliths and bone erosions on plain films in four patients with extra-articular soft tissue involvement pointed to the correct diagnosis. Angiography, showing fine-caliber, smooth-walled vessels, contrast pooling in dilated vascular spaces, and early visualization of venous structures, was diagnostic in two patients. Neither arthrography nor CT yielded specific enough findings. MRI was consistently effective in allowing the correct diagnosis to be made preoperatively, showing an intra-articular or juxta-articular mass of intermediate signal intensity on T1-weighted images and of high signal intensity on T2or T2^*-weighted images with low-signal channels or septa within it. A fluid-fluid level was found in two patients with a cavernous-type lesion.Conclusion Despite the limited nature of this study, it shows clearly that MRI is the procedure of choice whenever an intra-articular vascular lesion such as synovial hemangioma is suspected. Nonetheless, phleboliths and evidence of extra-articular extension on plain radiographs point to angiography as an effective procedure of first resort because it can be combined with embolotherapy.     

Posttraumatic pseudolipoma: MRI appearances

The goal of this study was to describe the MRI characteristics of posttraumatic pseudolipomas. Ten patients with previous history of blunt trauma or local surgery were investigated with MRI at the level of their deformity. The etiology was blunt trauma in eight patients and postoperative trauma in two. For all patients medical documentation, in the form of clinical history and physical examination, confirmed that a visible hematoma was present acutely at the same location following the injury and that the contour deformity subsequently appeared. All patients underwent liposuction. Preoperative bilateral MRI examinations were performed on all patients. The mean clinical follow-up was 17.8 months. MRI examinations were interpreted in consensus by two experienced musculoskeletal radiologists with attention to fatty extension (subcutaneous fatty thickness and anatomical extension), asymmetry compared with the asymptomatic side, the presence or absence of fibrous septae or nonfatty components, and patterns of contrast enhancement. Ten posttraumatic pseudolipomas were identified. Clinically, they showed as subcutaneous masses with the consistency of normal adipose tissue. Their locations were the abdomen (n=1), hip (n=1), the upper thigh (n=6), the knee (n=1), and the ankle (n=1). On MRI examinations, using the contralateral side as a control, pseudolipomas appeared as focal fatty masses without a capsule or contrast enhancement. Posttraumatic pseudolipomas may develop at a site of blunt trauma or surgical procedures often antedated by a soft tissue hematoma. Characteristic MRI findings are unencapsulated subcutaneous fatty masses without contrast enhancement.     

MRI evaluation of post-operative seromas in extremity soft tissue sarcomas

Objective. To define the spectrum of MRI appearances of postoperative seromas in patients who have undergone excision of extremity soft tissue sarcomas. Local recurrence is always of concern; often a second-look procedure is performed to assess this possibility. Unnecessary surgical exploration may be avoided if radiologists and orthopedic oncologists are familiar with this spectrum of MRI appearances. Design and patients. The medical records and images of 85 patients with extremity soft tissue sarcomas were reviewed. Postoperative MRI examinations were available in 46 patients. Eight of these demonstrated MRI evidence of postoperative seroma. The initial size, rate of change, margin, and internal architecture of each seroma was measured, calculated, graded, and graphed. Results and conclusion. MRI is an excellent modality for the evaluation of postoperative seromas. Globular areas of low to intermediate signal material within seromas may represent organized hematomas or granulation tissue rather than sarcoma recurrence. Local recurrence rarely occurs within seromas. Received: 12 November 1998 Revision requested: 22 January 1999 Revision received: 2 February 1999 Accepted: 22 February 1999     

Diagnostic value of delineating deep fascia in distinguishing between benign and malignant soft-tissue tumors in lower limbs using 3.0 T magnetic resonance imaging

Purpose

To determine the association between morphological changes to the deep fascia and the malignancy of soft‐tissue tumors in the lower limbs using 3.0 T magnetic resonance imaging (MRI).

Materials and Methods

MR images of 47 consecutive patients with 48 pathologically proven soft‐tissue tumors in the lower limbs were retrospectively reviewed by two radiologists. Lesions were divided into four groups according to their predominant location relative to the deep fascia: Group A: subcutaneous lesions superficial to the deep fascia (n = 9); Group B: lesions located beneath the deep fascia (n = 8); Group C: lesions centered in the interspaces of the deep fascia investment (n = 11); and Group D: intramuscular lesions (n = 20).

Results

The deep fascial structures were complete in all of the 19 benign lesions. In malignant lesions, destruction signs of the deep fascia were observed in 27 of the 29, which were characterized by disappearance/disruption of the fascial line and aggressive growth penetrating through the fascial line into the adjacent compartment, or disappearance/disruption of the intermuscular septa and embedding the mutilated fascial septa within the lesion, or destruction of the fascia‐muscle planes and abolishment of the deep fascial interspaces. Diagnosis of malignancy based on the signs of destruction of the deep fascial structure delineated with 3.0 T MRI, the sensitivity, specificity, and accuracy were 93.10%, 100%, and 95.83%, respectively.

Conclusion

Tumor involvement and destruction of the deep fascial structures visualized by 3.0 T MRI may be of utility in differentiating malignant from benign soft‐tissue tumors. J. Magn. Reson. Imaging 2011;33:173–179. © 2010 Wiley‐Liss, Inc.     

MR imaging of septic sacroiliitis

Objective. To investigate the diagnostic value of magnetic resonance (MR) imaging in detecting septic sacroiliitis and to determine whether the MR characteristics allow this entity to be differentiated from sacroiliitis in spondylarthropathy (SpA). Patients and design. The imaging findings of 11 patients with septic sacroiliitis were retrospectively analyzed by two experienced radiologists. Radiographic surveys of the pelvis as well as computed tomography (CT) and MR images of the sacroiliac joints were available in all cases. Seven of the patients additionally underwent a follow-up MR examination. The MR imaging protocol comprised combinations of coronal and transverse T1-weighted spin-echo (SE) or fast SE sequences, T2-weighted gradient-echo (GE) sequences and short tau inversion recovery sequence (STIR) sequences as well as dynamic contrast- enhanced T1-weighted acquisitions. Results. Three patients with a short disease history showed anterior and/or posterior subperiosteal infiltrations (”lava cleft phenomenon”), transcapsular infiltrations of juxta-articular muscle layers, which obscured the fasciae, and periarticular bone marrow edema. The eight patients with more advanced stages of sacroiliitis additionally showed abscess formation, sequestration, and erosion. At follow-up MR examination (n=7) under systemic antibiotic treatment, the morphologic characteristics showed progression (n=1), regression (n=4), unchanged findings (n=1), or a mixed response (n=1). Clinical improvement precedes resolution of the MR findings. Conclusions. Anterior and/or posterior subperiosteal infiltrations and transcapsular infiltrations of juxta-articular muscle layers were depicted in all patients. These MR imaging findings are characteristic of septic sacroiliitis and may be used to differentiate this entity from sacroiliitis in SpA. Received: 1 November 1999 Revision requested: 4 January 2000 Revision received: 14 April 2000 Accepted: 16 May 2000     

Magnetic resonance imaging features of allografts

Objective. To investigate the magnetic resonance imaging (MRI) features of allografts at various time intervals after surgery in patients with osteoarticular allografts. Design and patients. Sixteen patients who were treated with osteoarticular allografts and who were followed over time with MRI studies as part of their long-term follow-up were retrospectively selected for this study. T1-weighted images were obtained both before and after gadolinium administration along with T2-weighted images. All images were reviewed by an experienced musculoseletal radiologist, with two other experienced radiologists used for consultation. Imaging studies were organized into three groups for ease of discussion: early postoperative period (2 days to 2 months), intermediate postoperative period (3 months to 2 years), and late postoperative period (greater than 2 years). Results. In the early postoperative period, no gadolinium enhancement of the allograft was visible in any of the MR images. A linear, thin layer of periosteal and endosteal tissue enhancement along the margin of the allograft was visible in images obtained at 3–4 months. This enhancement apeared gradually to increase in images from later periods, and appears to have stabilized in the images obtained approximately 2–3 years after allograft placement. The endosteal enhancement diminished after several years, with examinations conducted between 6 and 8 years following surgery showing minimal endosteal enhancement. However, focal enhancement was noted adjacent to areas of pressure erosion or degenerative cysts. All the cases showed inhomogeneity in the marrow signal (scattered low signal foci on T1 with corresponding bright signal on T2), and a diffuse, inhomogeneous marrow enhancement later on. Conclusion. We have characterized the basic MRI features of osteoarticular allografts in 16 patients who underwent imaging studies at various time points as part of routine follow-up. We believe that the endosteal and periosteal enhancement observed on MRI during the first few months to 2 years following surgery represents vascular ingrowth and early skeletal repair. The zone of periosteal enhancement could also include the new bone laid on the surface of the allograft through which the soft tissues bind to the cortex. The exact reason for the inhomogeneity in the marrow signal, and the diffuse, inhomogeneous marrow enhancement is not clear. This may represent saponified and/or necrotic marrow fat interspersed with the fibrovascular tissue. The features noted here should provide radiologists with useful information regarding imaging characteristics they can expect to see in other allograft replacement patients. Received: 14 August 1998 Revision requested: 23 October 1998 Revision received: 2 February 1999 Accepted: 22 February 1999     

Alveolar soft part sarcoma: MR and angiographic findings

Objective. To present the MR and angiographic findings of alveolar soft part sarcoma (ASPS). Design and patients. MR examinations (12 tumors of 10 patients) of ASPS performed at multiple hospitals were retrospectively reviewed. The tumors were found in the thigh (n=4), lower leg (n=4), femur (n=2, local metastasis), scalp (n=1) and arm (n=1). The MR signal characteristics including signal intensity, homogeneity and signal void of lesions and bony invasion including direct invasion or local metastasis were evaluated. Angiographic findings (n=4) and post-embolotherapy follow-up MR imaging (n=2) findings were also assessed. Results. Local bony metastasis was found in two cases. Seven tumors showed heterogeneous high signal intensity on T1- and T2-weighted images with good enhancement. One tumor had a very high signal on T1-weighted images. Eight tumors (67%) showed numerous signal voids in or near the tumors. All four angiographic studies showed numerous enlarged vessels, arteriovenous shunts and delayed washout. Two cases mimicked arteriovenous malformations on angiographic studies but MR images demonstrated solid soft tissue components as well as tortuous vessels. Conclusions. High signal on T1-weighted image and numerous signal voids are highly suggestive of ASPS, although they are not universal as has been suggested and arteriovenous malformation should be included in the differential diagnosis. Local bony metastases in ASPS were seen in two cases and should be carefully investigated. Received: 12 April 2000 Revision requested: 27 June 2000, 8 August 2000 Revision received: 2 August 2000, 21 August 2000 Accepted: 22 August 2000     

The radiological findings in chronic expanding hematoma

Objective. To identify the characteristic MRI findings of chronic expanding hematoma correlated with the pathology. Design and patients. Three patients who had a chronic expanding hematoma involving the musculoskeletal system were reviewed retrospectively. Results and conclusion. Huge soft tissue masses suggestive of malignancy with destruction of the bony structure were revealed on radiography and computed tomography. MRI showed the masses to exhibit heterogeneous signal intensity on both T1- and T2-weighted images with a peripheral rim of low signal intensity, reflecting the central zones of fluid collection due to fresh and altered blood with a wall of collagenous fibrous tissue. These MRI findings were seen in all three patients and are considered to be characteristic; they assist in differentiation from neoplasm in consideration of the history of trauma or surgery. Received: 11 December 1998 Revision requested: 19 April 1999 Revision received: 21 May 1999 Accepted: 27 May 1999     

Magnetic resonance signal alterations in the acute onset of heterotopic ossification in patients with spinal cord injury

The purpose of our study was to evaluate magnetic resonance (MR) signal characteristics of acutely forming heterotopic ossification (HO) in paralyzed patients. Fourteen patients with spinal cord injury (female n=2, male n=12, mean age 38.3 years) and acute onset of radiographically proven HO had contrast-enhanced 1.5-T MRI within 13.4±18.3 days of clinical onset of symptoms. MR signal alterations of affected muscles, fascia, subcutaneous tissue, skin and adjacent bone were evaluated. A diffuse T2-hyperintense signal of multiple muscle groups was seen in all patients (bilateral in 12) involving quadriceps (n=13, 93%), adductors (n=13, 93%) and iliopsoas (n=12, 86%) with contrast enhancement in n=11 (79%), n=8 (57%) and n=8 (57%) patients. All patients had nonenhancing areas (mean size 2×3.5×5.8 cm) within diffusely enhancing muscles. HO formation occurred around these nonenhancing areas in four patients with computed tomography follow-up. Other MR findings included fascial edema (n=14, 100%), fascial enhancement (n=13, 93%), subcutaneous edema (n=13, 93%), subcutaneous enhancement (n=12, 86%), bone marrow edema (n=5, 36%), and joint effusion (n=12, 86%). MRI reveals mostly bilateral edema and enhancement of muscles, fascia and subcutaneous tissue during acute onset of HO. HO develops in the periphery of well-defined areas of no enhancement.     

Comparison of MRI (including SS SE-EPI and SPIO-enhanced MRI) and FDG-PET/CT for the detection of colorectal liver metastases

Fluoro-18-deoxyglucose positron emission tomography computed tomography (FDG-PET/CT) and magnetic resonance imaging (MRI), including unenhanced single-shot spin-echo echo planar imaging (SS SE-EPI) and small paramagnetic iron oxide (SPIO) enhancement, were compared prospectively for detecting colorectal liver metastases. Twenty-four consecutive patients suspected for metastases underwent MRI and FDG-PET/CT. Fourteen patients (58%) had previously received chemotherapy, including seven patients whose chemotherapy was still continuing to within 1 month of the PET/CT study. The mean interval between PET/CT and MRI was 10.2 ± 5.2 days. Histopathology (n = 18) or follow-up imaging (n = 6) were used as reference. Seventy-seven metastases were detected. In nine patients, MRI and PET/CT gave concordant results. Sensitivities for unenhanced SS SE-EPI, MRI without SS SE-EPI and FDG-PET/CT were, respectively, 100% (p = 9 × 10⁻¹⁰ vs PET, p = 8 × 10⁻³ vs MRI without SS SE-EPI), 90% (p = 2 × 10⁻⁷ vs PET) and 60%. PET/CT sensitivity dropped significantly with decreasing size, from 100% in lesions larger than 20 mm (identical to MRI), over 54% in lesions between 10 and 20 mm (p = 3 × 10⁵ versus unenhanced SS SE-EPI), to 32% in lesions under 10 mm (p = 6 × 10⁻⁵ versus unenhanced SS SE-EPI). Positive predictive value of PET was 100% (identical to MRI). MRI, particularly unenhanced SS SE-EPI, has good sensitivity and positive predictive value for detecting liver metastases from colorectal carcinoma. Its sensitivity is better than that of FDG-PET/CT, especially for small lesions.     

Fibrolipomatous hamartoma: pathognomonic on MR imaging

Purpose. To assess the MR imaging characteristics, presenting symptoms, age and nerve distribution of fibrolipomatous hamartoma. Design. A computer search was performed of the term fibrolipomatous hamartoma through the musculoskeletal section MR imaging results at our institution from June 7, 1996 to January 21, 1998 followed by a search of the terms lipomatous hamartoma, median nerve, surrounding fat, increased fatty signal, coaxial, and neuroma. MR images and medical files were retrospectively reviewed by two experienced musculoskeletal radiologists for imaging characteristics, nerve and age distribution as well as for history of trauma. In addition three consultation cases from outside institutions were added for determination of image characteristics. Results. Ten fibrolipomatous hamartomas were identified: eight in the median nerve, one in the ulnar nerve and one in the sciatic nerve. Mean age was 32.3 years (range 4–75 years, SD 21 years). Imaging characteristics were serpiginous low-intensity structures representing thickened nerve fascicles, surrounded by evenly distributed fat, high signal intensity on T1-weighted sequences and low signal intensity on T2-weighted sequences. The amount of fat varied; however, distribution in eight cases (80%) was predominantly between nerve fibers rather than surrounding them peripherally. All had a coaxial-cable-like appearance on axial planes and a spaghetti-like appearance on coronal planes that was not seen in any other type of median nerve abnormality imaged during the study period. Conclusion. The MR imaging characteristics of fibrolipomatous hamartoma are pathognomonic, obviating the need for biopsy for diagnosis. Received: 19 October 1998 Revision requested: 11 December 1998 Revision received: 22 January 1999 Accepted: 25 January 1999     

”Spinolaminar breach”: an important sign in cervical spinous process fractures

Objective. To report the sign of ”spinolaminar breach” and its likely importance in fractures of the cervical spinous processes. Design. Six cases of spinous process fractures demonstrating disruption of the spinolaminar line or ”spinolaminar breach” were analyzed. Lateral and anteroposterior radiographs (n=6), CT scans (n=3) and MRI scans (n=1) were reviewed together by the authors, with consensus being reached as to the radiographic findings. Clinical records were also reviewed. Results. The levels of injury were C6 (n=5) and C5 (n=2). Injuries were associated with delayed anterior subluxation (n=4) and neurological deficit (n=2). Five patients were male and one was female with a mean age of 31 years (range 8–59 years). Injuries resulted from motor vehicle accidents (n=4), a motor cycle accident (n=1) and a fall (n=1). Conclusion. ”Spinolaminar breach”, or disruption of the spinolaminar line, indicates a complex spinous process fracture with extension into the lamina and spinal canal. Spinous process fractures with spinolaminar breach may have associated posterior ligamentous injury with potential for delayed instability and neurological deficit. It is important that radiologists and physicians caring for the trauma patient be aware of this sign in order to avoid misdiagnosis as a ”clay shoveler’s fracture”, which can lead to adverse outcome. Received: 20 July 1999 Revision requested: 14 September 1999 Revision received: 13 October 1999 Accepted: 26 October 1999     

Type I Gaucher disease: extraosseous extension of skeletal disease

Objective. To investigate the frequency and morphology of extraosseous extension in patients with Gaucher disease type I. Design and patients. MRI examinations of the lower extremities were analyzed in 70 patients with Gaucher disease type I. Additionally, the thoracic spine and the midface were investigated on MRI in two patients. Results. Four cases are presented in which patients with Gaucher disease type I and severe skeletal involvement developed destruction or protrusion of the cortex with extraosseous extension into soft tissues. In one patient, Gaucher cell deposits destroyed the cortex of the mandible and extended into the masseter muscle. In the second patient, multiple paravertebral masses with localized destruction of the cortex were apparent in the thoracic spine. In the third and fourth patient, cortical destruction with extraosseous tissue extending into soft tissues was seen in the lower limbs. Conclusions. Extraosseous extension is a rare manifestation of Gaucher bone disease. While an increased risk of cancer, especially hematopoietic in origin, is known in patients with Gaucher disease, these extraosseous benign manifestations that may mimic malignant processes should be considered in the differential diagnosis of extraosseous extension into soft tissues. A narrow neck of tissue was apparent in all cases connecting bone and extraosseous extensions. Received: 19 July 1999 Revision requested: 8 September 1999 Revision received: 7 October 1999 Accepted: 14 October 1999     

A pilot study using magnetic resonance imaging to determine the pattern of muscle group recruitment by rowers with different levels of experience

Objective. To determine whether it was possible using magnetic resonance imaging (MRI) to define the pattern of muscle recruitment in a specific sport (rowing) and to see whether there were differences in this pattern between athletes of different experience. Design and method. It has been shown that during vigorous exercise the water content of muscle increases transiently. This can be observed using MRI, where the prolonged T2 relaxation time of muscle can be demonstrated. In this study we have exploited the increase in signal seen in exercised muscle on short TI inversion recovery (STIR) sequences, to show how rowers of different experience use different muscle groups. Results.We have shown that trained athletes recruit selected muscle groups to carry out a given task, which they carry out more efficiently than untrained or less experienced athletes. Conclusion.We have provided the basis of potential research to refine training methods, in order to develop specific muscle groups in athletes, in the hope of achieving a higher level of performance at an earlier stage in their training. We have also defined a technique that may be of clinical value in cases of muscle dysfunction. Received: 13 September 1999 Revision requested: 19 November 1999 Revision received: 30 December 1999 Accepted: 4 January 2000     

Detection of pericardial inflammation with late-enhancement cardiac magnetic resonance imaging: initial results

Objective: To examine the value of late-enhancement cardiac magnetic resonance imaging (MRI) for detection of pericardial inflammation. Materials and methods: Late-enhancement cardiac MRI was performed in 16 patients with clinical suspicion of pericardial disease. Pericardial effusion, pericardial thickening and pericardial enhancement were assessed. MRI findings were compared with those of definitive pericardial histology (n=14) or microbiology (n=2). A control group of 12 patients with no clinical evidence of pericardial disease were also imaged with the same MRI protocol. Results: Sensitivity and specificity for late-enhancement MRI detection of pericardial inflammation was of 100%. There was MRI late enhancement of the pericardial layers in all five patients with histological/microbiological evidence of inflammatory pericarditis. MRI demonstrated no pericardial thickening and no MRI late enhancement with or without a pericardial effusion in any of the five patients with histological evidence of a normal pericardium. MRI detected pericardial thickening in the absence of both pericardial effusion and late enhancement in all six patients with histological evidence of chronic fibrosing pericarditis. The 12 control subjects showed no evidence of pericardial MRI late enhancement. Conclusions: These findings demonstrate that MRI late enhancement can be used to visualize pericardial inflammation in patients with clinical suspicion of pericardial disease.     

MRI and <Superscript>1</Superscript>H MRS findings in Smith-Lemli-Opitz syndrome

Smith-Lemli-Opitz syndrome (SLOS) is an autosomal recessive disorder characterized by a defect in cholesterol biosynthesis, associated with mental retardation and multisystem structural abnormalities. This study investigated the prevalence of congenital CNS abnormalities by MRI in a large series of patients with SLOS and the correlation of the clinical and biochemical findings with the results of MRI and ¹H MRS. Eighteen patients were studied; all underwent MRI of the brain, and 16 had ¹H MRS of the cerebral white matter. The ratios choline:NAA, lipid:NAA, and lipid:choline metabolite were found to be correlated with the clinical degree of disease severity, serum total sterol ratios (cholesterol/cholesterol + 7-dehydrocholesterol + 8-dehydrocholesterol) and in two cases with the effect of cholesterol therapy. Abnormal CNS findings were noted in five patients, including callosal abnormalities (n=4), Dandy-Walker variant (n=1), and arachnoid cyst (n=1). Holoprosencephaly was noted in one patient with a prevalence of 6%. Choline:NAA was elevated in seven patients. There was a statistically significant positive correlation between the lipid:choline ratio and the serum cholesterol precursor, 8-dehydrocholesterol. In two patients ¹H MRS demonstrated abnormally elevated lipids prior to cholesterol therapy, which improved on therapy. The use of MRI and ¹H MRS is an effective way to demonstrate brain structural abnormalities in patients with SLOS and may prove to be an effective method for the assessment of the effects of cholesterol replacement therapy in the brain.