Biomedical subjects

J Laubenberger

Publications and source records attributed to J Laubenberger.

At least 37 records · Page 2Linked to original sources

PubMed1999

MRI of heart morphology. Comparison of nongradient echo sequences with single- and multislice acquisition.

RATIONALE AND OBJECTIVES: A large variety of cardiac MRI sequences have been introduced for heart morphology evaluation. The aim of this study was to establish a practicable and robust examination protocol for standard high-field systems applying nongradient echo sequences with single- and multi-slice acquisition. METHODS: Fifty-one patients received electrocardiogramgated MRI of the heart with "black-blood" preparation, comparing three single-slice and three multislice sequences with a T1-weighted turbo spin echo reference sequence. Demarcation of the left ventricular myocardium and cavity and the extent of flow and motion artifacts were assessed. RESULTS: The myocardium and left ventricular cavity were depicted best with the single-slice T1- and T2-weighted turbo spin echo sequence. The nonbreath-hold multislice sequences produced marked artifacts and therefore were of poor diagnostic value. The TIRM haste sequence was best suited for fat suppression. The T2-weighted breath-hold single-shot sequence with half-Fourier imaging proved to be most appropriate for multislice imaging. CONCLUSIONS: Sufficient depiction of heart morphology with comprehensive evaluation of signal changes can be achieved using nongradient spin echo and turbo spin echo sequences with breath-holding. For rational imaging of myocardial and heart chamber morphology, multislice and single-slice sequences should be combined.

Adult↗

PubMed1999

Pelvic imaging with a selenium-based detector (Thoravision). Comparison with screen-film radiography in 75 patients.

OBJECTIVE: To evaluate whether the selenium detector (Thoravision) provides sufficient diagnostic confidence in digital pelvic imaging compared with a conventional screen-film combination. METHODS: In 75 patients, pelvic imaging with conventional screen-film and isodose selenium radiography using a dedicated postprocessing mode was compared independently by three radiologists. The depiction of cortical and cancellous bone was evaluated in the iliac wings, sacral and pubic bones, acetabulum, femoral head, and trochanter. Demarcation of soft tissue was assessed in the iliac and trochanteric region. RESULTS: Visualization of cortical bone and soft tissue in the iliac area as well as soft tissue and cortical and cancellous bone in the trochanteric region was significantly superior with the selenium detector. However, conventional imaging was better in the trabecular bone of the sacral region, where results with the selenium system were particularly poor. CONCLUSIONS: The selenium detector (Thoravision) is advantageous in imaging soft tissue adjacent to the iliac wings and the trochanter, but results for the cancellous sacral bone are poor. Further modifications of postprocessing modes may lead to improved depiction of this critical pelvic area.

Adult↗

PubMed1998

Sinus venous thrombosis: an unusual cause for neurologic symptoms after bone marrow transplantation under immunosuppression.

BACKGROUND: Hematopoietic and organ transplantations are increasing worldwide with more patients receiving immunosuppressive therapy. Neurological problems may complicate the posttransplant period. Possible causes include the conditioning regimen (e.g., seizures with busulfan), central nervous system infections (viral, bacterial, and fungal), or factors secondary to the immunosuppressive therapy and side effects of drug treatment (e.g., cyclosporine and tacrolimus). Sinus venous thrombosis, the occlusion of a cerebral venous vessel or a sinus, is an unusual cause of neurologic symptoms in patients after transplantation, and this has not been reported in the literature previously. METHODS: Three patients presenting with various neurological symptoms after allogeneic bone marrow transplantation underwent computed tomography scans and magnetic resonance imaging as a primary diagnostic procedure. RESULTS: In all patients, sinus venous thrombosis was found as the cause for seizures; it was the cause of disturbance of consciousness in two patients and headaches in two patients. All symptoms resolved without any neurologic deficiency after anticoagulation therapy with heparin followed by dicumarol. CONCLUSION: We conclude that sinus venous thrombosis should be considered as a cause of neurological symptoms in patients after transplantation under immunosuppressive therapy. Diagnosis is rapidly confirmed by noninvasive magnetic resonance imaging angiography. Therapeutic heparinization is the treatment of choice.

Adult↗

PubMed1998

[Using autoclaved spongiosa].

Since transmission of HIV through allogenic bone grafts has been established, the concept of cryopreservation of allogenic bone had to be reconsidered. The strict guidelines of the scientific board of the Bundesärztekammer of 1990 are very labour-, time- and money-intensive. We have therefore moved to autoclaving allogenic cancellous bone. This is harvested from femoral heads during THR in slices of 2 to 3 mm, then cleaned under non-sterile conditions with a hard water jet followed by an ultrasonic bath for approx. 20 minutes. The slices are then double sealed individually and autoclaved at a temperature of 134 degrees C and a pressure of 2.5 atmospheres. Storage is in sealable containers at room temperature, so the material available at any time. Since the bone tissue has been freed of most organic matter and therefore lost its bone-specific antigenic structure, all that is left is the anorganic component with its inimitable architecture. This treatment results in a cancellous bone graft which is sterile, biocompatible and osteoconductive. Biologically it is inferior to autogenic and cryopreserved bone. Experimental and clinical studies show, however, that autoclaved cancellous bone can be a suitable substitute in well-selected indications. To elucidate the ultrastructural changes of the spongiosa and proteins induced by autoclaving further investigations are necessary. For example, the specific proteins involved need to be determined.

Bone Transplantation↗

PubMed1998

MR findings in pontocerebellar hypoplasia.

We present four cases with combined hypoplasia of the cerebellum and the ventral pons-pontocerebellar hypoplasia (PCH). PCH represents an autosomal recessive neurodegenerative disorder with fetal onset. The disease is rare, with less than 20 cases having been reported. The main findings of PCH and the inclusion criteria for our cases can be summarised as progressive microcephaly from birth, pontocerebellar hypoplasia documented by MRI and marked chorea, which may change, later in childhood, to more dystonic patterns. The cerebral cortex becomes progressively atrophic. Motor and mental development are delayed, and epilepsy, mainly tonic-clonic seizures, is frequent. The MRI features in all of our cases were: (1) Hypoplastic cerebellum situated close to the tentorium. The hypoplastic cerebellum has a reduced number of folia, in contrast to the normal number of thin folia in simple cerebellar atrophy. (2) The cerebellar hemispheres are reduced to bean-like or wing-like structures. The cerebellar hemispheres appear to 'float' in the posterior fossa. (3) Markedly hypoplastic ventral pons. (4) Slight atrophy of the supratentorial gyral pattern. (5) Dilated cerebromedullary cistern and fourth ventricle. (6) Delayed myelination of the white matter. (7) No significant disorganisation of brain architecture and no severe corpus callosum defect.

Cerebellum↗

PubMed1998

Comparison of turbo inversion recovery magnitude (TIRM) with T2-weighted turbo spin-echo and T1-weighted spin-echo MR imaging in the early diagnosis of acute osteomyelitis in children.

OBJECTIVE: To compare turbo inversion recovery magnitude (TIRM) with standard T1-weighted (T1-W) and T2-weighted (T2-W) MR sequences in the very early detection of acute osteomyelitis in children. MATERIALS AND METHODS: In 15 children with osteomyelitis, 15 sets of T1-W spin-echo (SE) (TR/TE, 400-640/12-17), T2-W turbo spin-echo (TSE) (TR/TE/ETL, 3290-4465/112-120/11), and TIRM (TR/TE/TI, 4000-6120/60/160) images were acquired with a 1.0-T magnet. Contrast-to-noise (C/N) ratios and percentage of signal between lesion and normal bone marrow were analysed with a computer-assisted image analysing system in a region of interest (ROI). RESULTS: In 13 of 15 patients, the absolute signal enhancement in a ROI on the TIRM images was better than on the T1-W SE and T2-W TSE images and in 14 of 15 cases, C/N ratios were also better on the TIRM images than on the other sequences. In the other cases, the TIRM signal was diagnostically equivalent. On the TIRM images, the signal difference between normal and pathological tissue was increased to 43-281% (mean 124%). On the T2-W TSE images, this signal difference was 4-79% (mean 36%) and on the T1-W SE images 6-77% (mean 37%). Conclusion. The TIRM sequence is highly sensitive for detecting bone marrow oedema in the very early stage of acute osteomyelitis in children. MRI utilising the TIRM sequence allowed for an early diagnosis. With scan time of less than 4 minutes, this sequence is superior to T1-W SE and T2-W TSE images for detecting early osteomyelitis-associated bone marrow oedema.

Acute Disease↗

PubMed1998

Human articular cartilage: in vitro correlation of MRI and histologic findings.

The aim of our study was to correlate MRI with histologic findings in normal and degenerative cartilage. Twenty-two human knees derived from patients undergoing amputation were examined with 1.0- and 1. 5-T MR imaging units. Firstly, we optimized two fat-suppressed 3D gradient-echo sequences. In this pilot study two knees were examined with fast imaging with steady precession (FISP) sequences and fast low-angle shot (FLASH, SPGR) sequence by varying the flip angles (40, 60, 90 degrees) and combining each flip angle with different echo time (7, 10 or 11, 20 ms). We chose the sequences with the best visual contrast between the cartilage layers and the best measured contrast-to-noise ratio between cartilage and bone marrow. Therefore, we used a 3D FLASH fat-saturated sequence (TR/TE/flip angle = 50/11 ms/40 degrees) and a 3D FISP fat-saturated sequence (TR/TE/flip angle = 40/10 ms/40 degrees) for cartilage imaging in 22 human knees. The images were obtained at various angles of the patellar cartilage in relation to the main magnetic field (0, 55, 90 degrees). The MR appearances were classified into five categories: normal, intracartilaginous signal changes, diffuse thinning (cartilage thickness < 3 mm), superficial erosions, and cartilage ulcers. After imaging, the knees were examined macroscopically and photographed. In addition, we performed histologic studies using light microscopy with several different stainings, polarization, and dark field microscopy as well as electron microscopy. The structural characteristics with the cartilage lesions were correlated with the MR findings. We identified a hyperintense superficial zone in the MR image which did not correlate to the histologically identifiable superficial zone. The second lamina was hypointense on MRI and correlated to the bulk of the radial zone. The third (or deep) cartilage lamina in the MR image seemed to represent the combination of the lowest portion of the radial zone and the calcified cartilage. The width of the hypointense second zone correlated weakly to the accumulation of proteoglycans in the radial zone. The trilaminar MRI appearance of the cartilage was only visible when the cartilage was thicker than 2 mm. In cartilage degeneration, we found either a diffuse thinning of all layers or circumscribed lesions ("cartilage ulcer") of these cartilage layers in the MR images. Early cartilage degeneration was indicated by a signal loss in the superficial zone, correlating to the histologically proven damage of proteoglycans in the transitional and radial zone along with destruction of the superficial zone. We found a strong effect of cartilage rotation in the main magnetic field, too. A rotation of the cartilage structures caused considerable variation in the signal intensity of the second lamina. Cartilage segments in a 55 degreesangle to the magnetic main field had a homogeneous appearance, not a trilaminar appearance. The signal behavior of hyaline articular cartilage does not reflect the laminar histologic structure. Osteoarthrosis and cartilage degeneration are visible on MR images as intracartilaginous signal changes, superficial erosions, diffuse cartilage thinning, and cartilage ulceration.

Aged↗

PubMed1998

[RARE urography in pelvic tumors: diagnostic ranking and comparison with intravenous pyelography].

PURPOSE: To examine if RARE urography may replace conventional intravenous urography in patients with suspected urinary obstruction in pelvic tumours. MATERIALS AND METHODS: In a prospective trial on 120 patients with pelvic tumours scheduled for operation, biplanar RARE urography was performed and compared to conventional intravenous urography and ultrasound findings. RESULTS: In 30 out of 120 patients an ureteric obstruction was diagnosed by ultrasound. Sensitivity of RARE urography for obstruction was 98% as compared to 60% in conventional intravenous urography. In 12 patients additional retrograde cystoureterography showed a sensitivity of 83%. Specificity of RARE urography and intravenous urography was 100%. In combination with axial MR tomography RARE urography yielded a more precise localisation of the site of obstruction and the underlying cause (98%) as compared to conventional urography (60%) and ultrasound (56%). CONCLUSION: By use of RARE urography urinary obstruction can be reliably demonstrated or ruled out. Combining RARE urography with tomographic MR imaging allows the precise depiction of the site of the obstruction and may demonstrate the underlying pathology.

Aged↗

PubMed1998

[Clinical uses of proton magnetic resonance spectroscopy of the brain].

In spite of all the scientific advances of the past few years, proton magnetic resonance spectroscopy of the brain has not attained the status of a routine examination technique with clinically accepted indications. The method should be considered as an additional option to MR imaging for inherited and acquired encephalopathic changes as well as, in future, for localization diagnosis of epilepsies. A proton magnetic resonance spectroscopic investigation without a prior intensive clinical and imaging investigation is not useful. Above all, factors influencing metabolite distribution such as for example, serum osmolality must be known. Methodological prerequisites for the clinical application of proton resonance spectroscopy are, first of all, a high stability of the chosen technique as well as a sufficiently certain quantification of metabolites and the availability of a reference group. The use of short echo times is necessary for the quantification of glutamine and the osmolyte myo-inositol. Indications for individual cases in which clinical investigations and MR topography cannot provide sufficient certainty and spectroscopy can furnish additional information are, in addition to uses in neuropediatrics, the suspicion of Alzheimer's dementia, HIV encephalopathy in early manifestations, and unclarified depressions of consciousness accompanying liver cirrhosis.

AIDS Dementia Complex↗

PubMed1998

Magnetic resonance diagnosis of the anterior labrum and capsule. Effect of field strength on efficacy.

RATIONALE AND OBJECTIVES: The authors compare the performance of high-field and low-field magnetic resonance (MR) systems in the evaluation of shoulder instability, 35 patients were examined at field strengths of 1.0 T and of 0.2 T. METHODS: Surface coils were used in both systems. Because arthroscopy was used as gold standard, a preselected patient-population was obtained for the study. RESULTS: The sensitivity/specificity/accuracy of MR images acquired at 1.0 T for labrum pathology were 91%/67%/91% and 70%/80%/71% for the capsular complex. Compared with the above, the sensitivity/specificity/accuracy for 0.2 T MR images revealed 91%/67%/91% for the labrum pathology and 63%/80%/66% for the capsular complex respectively. In the evaluation of capsular lesions a comparison between the 0.2 T MR system and the 1.0 T system indicated a higher sensitivity and accuracy for the high-field images. Concerning labral lesions, the sensitivity and accuracy of the 0.2 T MR imager and the 1.0 T imager were comparable. CONCLUSIONS: Given differences in imaging protocols, imaging at 0.2 T does not adversely affect the assessment of shoulder instability when compared with imaging at 1.0 T. These preliminary results warrant more extensive clinical comparison of results obtained at different magnetic field strengths.

Adolescent↗

PubMed1998

Comparison of MR sequences in quantifying in vitro cartilage degeneration in osteoarthritis of the knee.

Magnetic resonance imaging of amputated human knees was performed to determine optimal sequences for depicting articular cartilage. 24 knees were examined with eight different sequences in a 1.0 T imager. Each cartilage lesion was graded from 1 to 4 (Outerbridge staging system). The results of each sequence were compared with the macroscopic findings and statistically tested against each other. The FLASH sequence (TR = 50 ms) with combination of flip angle of 40 degrees and echo time of 10 ms and the FISP sequence (TR = 40 ms) with combination of flip angle of 40 degrees and echo time of 11 ms were best for depicting cartilage structure and internal detail. There was no significant difference between fat-saturated three-dimensional FLASH (FS-3D-FLASH) and FS-3D-FISP (p = 0.05). These FS-3D sequences were significantly better than sequences without fat saturation (p = 0.05). There was no significant difference between magnetization transfer (MT) 3D-FLASH, MT-3D-FISP and 3D-FISP. All 3D sequences showed significantly (p = 0.05) better results than spin echo or fast spin echo sequences. The T1 weighted SE pulse sequence was significantly (p = 0.005) better than the T2 weighted TSE sequence. Fast T2 weighted spin echo was not suitable for early and accurate detection of cartilage lesions.

Aged↗

PubMed1998

[Recent developments and applications of MRI sequence technique. I: turbo spin echo, HASTE, turbo inversion recovery, turbo gradient echo, turbo gradient spin sequences].

Goal of this two-part report is to provide clinical MRI radiologists with a guide to the world of new and clinically available MRI pulse sequences. Discussed are the principles of rapid scan techniques like multiple spin-echo imaging, multiple gradient echo imaging, echo planar imaging, diffusion and perfusion imaging, and future perspectives (review article).

Echo-Planar Imaging↗

PubMed1998

Prevalence, morphology and biology of renal cell carcinoma in von Hippel-Lindau disease compared to sporadic renal cell carcinoma.

PURPOSE: Renal cell carcinoma occurs as a sporadic tumor but may be part of the autosomal dominant von Hippel-Lindau disease, characterized by retinal and central nervous system hemangioblastoma, pheochromocytoma, pancreatic cysts and renal cell carcinoma. We determine the prevalence of von Hippel-Lindau disease in a series of unselected renal cell carcinoma cases by molecular genetic analysis, and compare sporadic to von Hippel-Lindau renal cell carcinoma with respect to morphology and biology. MATERIALS AND METHODS: We established registers comprising 63 subjects with von Hippel-Lindau renal cell carcinoma, belonging to 30 distinct families (register A), and 460 unselected patients operated on for renal cell carcinoma in an 11-year period (register B). Molecular genetic analysis of the von Hippel-Lindau gene was performed for living patients of register A, representing 80% of von Hippel-Lindau families, and register B, 62% living patients, to identify von Hippel-Lindau germline mutations. In addition, register B was evaluated by a questionnaire (95% response) for familial occurrence of von Hippel-Lindau disease. RESULTS: The prevalence of von Hippel-Lindau renal cell carcinoma was 1.6% in 189 consenting unselected renal cell carcinoma patients. Risk factors for occult germline von Hippel-Lindau gene mutations in register B included familial renal cell carcinoma in 3 of 3 patients (100%), multifocal or bilateral renal cell carcinoma in 1 of 10 (10%) and age younger than 50 years at diagnosis in 1 of 33 (3%). Compared to sporadic von Hippel-Lindau renal cell carcinoma was characterized by an occurrence 25 years earlier, association with renal cysts, multifocal and bilateral tumors, cystic organization and low grade histology, and a better 10-year survival (p < 0.001 each). In von Hippel-Lindau disease metastases occurred only in tumors larger than 7 cm. CONCLUSIONS: von Hippel-Lindau differs from sporadic renal cell carcinoma in morphology and biology. Our data provide arguments for planning surgery for von Hippel-Lindau renal cell carcinoma and should stimulate future investigations.

Adult↗

PubMed1997

Time-resolved projection angiography after bolus injection of contrast agent.

A method for MR angiography after bolus injection of a normal dose (0.1 mmol/kg) of contrast agent is presented. Projection angiograms are acquired with a non-slice selective Snapshot FLASH sequence with a time resolution of 1 s per image or better. Typically 40 to 60 images are acquired consecutively after bolus injection of a contrast agent. The signal from vessels can be separated from background by postprocessing based on the observed temporal evolution of the signal intensities during bolus passage. The subsecond projection MR-DSA is a reliable and robust technique to produce high resolution anatomical images of the vascular system avoiding the necessity of exact timing of the contrast agent bolus. It also supplies functional information about the hemodynamics in the observed region including perfusion.

Contrast Media↗

PubMed1997

Magnetic resonance: a multimodal approach to the brain?

Magnetic resonance of the brain offers the unique possibility of acquisition of morphological data in high resolution quality, analysis of metabolic disturbances, and the assessment of brain function. Basic principle is the BOLD effect, using the difference of the magnetic moments of oxy- and deoxyhemoglobin as intrinsic mechanism of contrast. Still the optimum techniques for functional imaging are not established: echo planar imaging requires a very costly hardware, whereas gradient echo imaging is feasible on clinical routine MR scanners. Although many experimental studies have been published on visual, motor, and auditory paradigms, clinical applications have not been established up to now. Analysis of epileptogenic foci combining high resolution imaging and functional information seems very promising as well as preoperative determination of critical areas in neurosurgery.

Brain↗

PubMed1997

Proton magnetic resonance spectroscopy of the brain in symptomatic and asymptomatic patients with liver cirrhosis.

BACKGROUND & AIMS: Hepatic encephalopathy (HE) is associated with typical changes of cerebral metabolite pattern observed by proton magnetic resonance (MR) spectroscopy consisting of a depletion of myo-inositol and an increase of glutamine. The aim of this study was to determine whether abnormalities in brain metabolism in neurologically asymptomatic patients with liver cirrhosis can be detected by spectroscopy. METHODS: In a prospective study, 39 patients with liver cirrhosis were examined clinically according to standardized neuropsychological tests to define whether overt, subclinical, or no hepatic encephalopathy was present. All patients underwent proton MR spectroscopy at short echo times. RESULTS: Spectroscopy allowed for the diagnosis of subclinical HE in 4 of 4 cases and of overt HE in 10 of 11 cases. In 24 cases of mere liver cirrhosis and normal neuropsychological testing, a typical metabolic pattern with a depletion of myo-inositol and an increased glutamine peak were found. A good correlation between the glutamine signal and the clinical grading was found. CONCLUSIONS: Proton MR spectroscopy allows for the diagnosis of HE and subclinical HE, also shows the typical pathological metabolite pattern in patients with cirrhotic livers without subclinical HE, and might be more sensitive than neuropsychological testing. Glutamine could serve as a spectroscopic marker for the clinical state of the patients.

Aged↗

PubMed1997

Prospective evaluation of bone marrow signal changes on magnetic resonance tomography during high-dose chemotherapy and peripheral blood stem cell transplantation in patients with breast cancer.

RATIONALE AND OBJECTIVES: The authors evaluate bone marrow signal changes on magnetic resonance (MR) imaging during high-dose chemotherapy and peripheral blood stem cell transplantation (PBSCT). METHODS: Fourteen patients with breast cancer without bone metastases underwent four sagittal MR imaging studies with T1-weighted, T2-weighted turbo spin-echo and inversion recovery sequences with short inversion time (STIR) of the lumbar spine: (1) during initial staging, (2) prior to high-dose chemotherapy after two cycles of induction chemotherapy, (3) early after PBSCT with a leukocyte exceeding 2000/microL, and (4) 6 to 8 weeks after PBSCT. Signal intensity ratios of averaged lumbar bone marrow to nucleus pulposus were measured and homogeneity was evaluated visually using a semiquantitative score. RESULTS: Compared with the initial finding (1): Signal intensity ratios were altered significantly at (2): T1-weighted: -22% +/- 14, P < 0.001; T2-weighted: -11% +/- 11, P < 0.01; STIR: +33% +/- 31, P < 0.01; Signal intensity ratios were altered significantly at (3): T2-weighted: -23% +/- 12, P < 0.001, STIR: -22% +/- 23, P < 0.01; and Signal intensity ratios were altered significantly at (4): only STIR: -16% +/- 19, P < 0.01. Homogeneity scores decreased at (3) for T1-weighted and STIR sequences (-1.6 +/- 0.5 to -2.0 +/- 0.7, P < 0.01 and -1.0 +/- 0.5 to -1.4 +/- 0.5, P < 0.01, respectively) and at (4) for the latter sequence (-1.0 +/- 0.5 versus -1.4 +/- 0.5, P < 0.01). At (4), T1-weighted images were less homogenous than initially in 3 of 14 (21%) patients. CONCLUSIONS: Magnetic resonance imaging demonstrates significant alterations of bone marrow composition during PBSCT but allows differentiation of benign therapy-related changes from those known in metastatic disease after completion of PBSCT.

Antineoplastic Agents↗

PubMed1997

Median nerve compression can be detected by magnetic resonance imaging of the carpal tunnel.

OBJECTIVE: Clinically symptomatic carpal tunnel syndrome is not necessarily accompanied by impaired nerve conduction values. Surgical decompression, however, may immediately lead to complete and lasting relief of symptoms in these patients. Because minimally invasive techniques have reduced perioperative morbidity and vocational impairment related to operative decompression, the decision to decompress symptomatic patients (despite still unimpaired nerve conduction values) might be subject to discussion in the future. New diagnostic tools may be helpful in deciding which therapeutical options to choose. When the wrist is held either in flexion or in extension, the carpal tunnel pressure increases. To investigate the dynamic changes of the carpal tunnel shape during wrist motion, as well as the variations of space for the median nerve and its signal intensity in T2-weighting, magnetic resonance imaging (MRI) was performed on patients and healthy volunteers alike. Restitution and the persistence of pathological findings were assessed pre- and postoperatively. METHODS: MRI (1.0 T) was performed on 20 wrists of patients with clinical symptoms of carpal tunnel syndrome (CTS) and pathological nerve conduction values. Healthy volunteers (20 wrists) were matched according to sex and age. MRI was performed in neutral, 45-degree extension, and 45-degree wrist flexion positions. T2-weighted signal intensity of the median nerve was measured in 18 patients pre- and postoperatively. RESULTS: The cross-sectional area of the carpal tunnel in patients with CTS tends to be smaller than that found in nonsymptomatic volunteers. The cross-sectional area of the carpal tunnel decreases during wrist flexion at the pisiform and hamate level. During wrist extension, the cross-sectional area of the carpal tunnel decreases at the level of the pisiform. During extension, it increases at the level of the hamate. The cross-sectional area of the median nerve showed an increase at the pisiform level (P < 0.05), a flattening of the median nerve at the hamate hook level (P < 0.05), and palmar deviation of the flexor retinaculum at the pisiform and hamate hook level (P < 0.001). This was significantly greater in CTS patients than in individuals with normal wrists. Postoperatively, the distal flattening of the median nerve recovered in 94% of the cases reviewed. Although the signal intensity of the median nerve on T2-weighted images decreased by 67%, the motor latency recovered in only 39% of the cases. CONCLUSION: The carpal tunnel was smaller in CTS patients than in healthy volunteers. During flexion and extension, the space available for the median nerve narrows. This may lead to potential median nerve compression. MRI is accurate and reliable for diagnosis and postoperative follow-up of carpal tunnel syndrome. In cases with obvious clinical symptoms and yet not measurably impaired median nerve conduction values, it may be helpful in making a decision for surgical decompression.

Adult↗