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PubMed1995

Radiofrequency catheter ablation of type 1 atrial flutter. Prediction of late success by electrophysiological criteria.

BACKGROUND: Radiofrequency energy has demonstrated its efficacy in catheter ablation of atrial flutter (AFl). However, long-term recurrences of AFl have been reported frequently after initial, apparently successful ablation. To date, criteria for prediction of late recurrences are lacking. METHODS AND RESULTS: Twelve patients (10 men; mean age, 53.6 years; range, 26 to 69 years) were referred for AFl ablation. Duodecapolar and decapolar catheters were used for detailed mapping of the tricuspid ring, the inferior vena cavatricuspid annulus (IVC-TA) isthmus, and the coronary sinus ostium (CSOs) area. Additional multipolar catheters were used for recording activation of the coronary sinus and the CSOs-TA isthmus. AFl was present at baseline in 9 patients and was induced by proximal coronary sinus (PCS) pacing in 3. Counterclockwise right atrial activation was recorded in all patients. Primary success of ablation was defined as when AFl was no longer inducible even during isoproterenol infusion. AFl was successfully ablated in all 12 patients, with a median of 4 pulses delivered at the IVC-TA isthmus. In the 3 patients in whom AFl was induced, during PCS pacing in sinus rhythm before ablation, a collision of descending and ascending wave fronts was observed at the middle lateral right atrium (LRA). This activation pattern of the LRA also was noted after unsuccessful radiofrequency applications. Noninducibility of AFl after radiofrequency applications was associated with a change of activation pattern at the LRA and with an inversion of the activation sequence of the IVC-TA isthmus (from clockwise to counterclockwise) in 9 patients when pacing from the PCS. In 2 of 3 patients, despite noninducibility of atrial flutter, ablation was pursued to obtain evidence of permanent block of conduction at the IVC-TA isthmus. Finally, a completely descending LRA wave front was observed when pacing from the PCS in all patients except one. Low LRA pacing was also performed in 4 patients and showed evidence for block in the counterclockwise direction at the isthmus. During a follow-up of 9 +/- 3 months, AFl recurred in 1 patient; this was the only patient who showed no conduction block at the isthmus after the procedure. CONCLUSIONS: Direction of impulse propagation at LRA and block of propagation at the IVC-TA isthmus during PCS and low LRA pacing appear to be of interest in predicting long-term success of AFl ablation.

Adult↗

PubMed2005

Silent cerebral ischemia detected with diffusion-weighted imaging in patients treated with protected and unprotected carotid artery stenting.

BACKGROUND AND PURPOSE: Percutaneous transluminal angioplasty with stent (CAS) is an alternative method to endarterectomy in the revascularization of carotid artery stenosis. Protected CAS is currently used to prevent distal embolization. Diffusion-weighted MRI (DWI) is the most sensitive tool to evaluate silent cerebral ischemia. The purpose of this research was to assess the incidence of cerebral embolic lesions during CAS and to evaluate whether cerebral protection devices can reduce the number of silent cerebral ischemia with respect to unprotected CAS. METHODS: Fifty-two patients with high-grade internal stenosis underwent CAS; 30 patients (group a) were treated with a cerebral protection device, and 22 (group b) were treated without it. All of the patients were evaluated preoperatively and postoperatively with fluid-attenuated inversion recovery and DWI sequences to depict the number of new embolic silent cerebral lesions. RESULTS: Embolic silent cerebral lesions occurred in 30% of CAS. Cerebral protection devices reduce the number of new lesions significantly reducing the consistent lesions ipsilateral to the treated vessel. Inconsistent lesions do not differ in both groups of patients. Clinical, radiological, and procedural variables do not correlate with the appearance of new cerebral lesions. CONCLUSIONS: Embolic cerebral lesions detected with DWI are more frequent with unprotected CAS, although they are present also with the use of cerebral protection devices. Probably a part of silent cerebral lesions arise from the procedural maneuver in the aortic arch.

Aged↗

PubMed2002

Continuing optic nerve atrophy following optic neuritis: a serial MRI study.

To investigate optic neuritis as a model for atrophy in multiple sclerosis (MS) lesions we performed serial magnetic resonance imaging (MRI) on 10 patients with a history of optic neuritis using a fat saturated short-echo fast fluid-attenuated inversion recovery (sTE fFLAIR) sequence. The first study was performed a median of 19.5 months after the onset of optic neuritis and the second 1 year later. Using a computer-assisted contouring technique, a blinded observer calculated the mean area of the intro-orbital optic nerves. The mean area of affected optic nerves decreased over 1 year by 0.9 mm2 from 11.1 to 10.2 mm2 (p = 0.01). Poor visual acuity and decreased visual-evoked potential (VEP) amplitude were associated with atrophy. These findings suggest that atrophy is a feature of focal demyelinating lesions, it may evolve over several years, and may have functional significance. Optic neuritis provides a model to study the effect of inflammatory demyelination through the ability to accurately measure visual function and to visualize and measure the optic nerves using magnetic resonance imaging.

Adult↗

PubMed2003

Early MRI in the management of clinical scaphoid fracture.

The incidence of MRI detected scaphoid and other wrist fractures was determined in a clinical setting in patients with suspicion of scaphoid injury and negative initial radiographs. The influence on subsequent patient management was examined. Patients attending Accident and Emergency over a 25 month period with suspected scaphoid fracture and normal scaphoid series plain films were referred for wrist MRI. Scans comprising T(1) weighted spin echo and short tau inversion recovery (STIR) coronal sequences were performed in a dedicated extremity low field MRI scanner within 14 days of injury. Subsequent effects on patient management were ascertained by clinician completed questionnaire. 195 patients were scanned. There were 37 scaphoid fractures (19%), 28 distal radius fractures (14%), 9 fractures of other carpal bones (5%) and 119 studies with no fracture. The management of 180 patients (92%) was altered as a result of the MRI scan. Occult fractures are present in almost two fifths of patients with suspected scaphoid fracture and normal initial plain films. Half of these are scaphoid fractures. MRI allows an early definitive diagnosis to be made, changing patient management in over 90% of cases and should be regarded as the gold standard investigation in this population.

Adolescent↗

PubMed2005

Adaptor long-range PCR procedure for clone-specific characterization and chromosomal localization.

An efficient adaptor long-range PCR (ALR-PCR) procedure was developed to detect genomic rearrangements in high-plasticity genomic regions between closely related strains of bacteria. The method was precisely optimized using a combination of high-speed experimental steps for the chromosomal localization and elucidation of deletions, inversions, duplications, or inserted sequences within a clone-specific flanking region. The advantages of this strategy are: (i) ready-to-use polymerase mixtures and Master mix (ready-to-use reaction mixtures with polymerase MasterAmp and buffer 2x Premix 4); (ii) a 5-min ligation procedure; (iii) rapid purification of DNA digests; (iv) optimized DNA template concentration protocol to avoid nonspecific amplification and high backgrounds; (v) long-range PCR protocol to obtain at least 9.6 kb single PCR products; (vi) two-step PCR cycling with the same annealing and extension temperature at 68 degrees C; (vii) simple design of the adaptors according to the preferred restriction endonuclease enzyme; and (viii) simple technology and equipment required. The application of this method for a tester-specific suppressive subtractive hybridization (SSH) clone of Brucella melitensis 16M revealed an 837-bp deletion and a 7255-bp DNA transfer from one chromosomal location to another for Brucella abortus 2308 used as a driver.

Base Sequence↗

PubMed1984

Magnetic resonance imaging of the kidneys.

A study of the magnetic resonance imaging (MRI) appearances of the kidneys in six normal volunteers and 52 patients is reported. Corticomedullary differentiation was seen with the inversion-recovery (IR 1400/400) sequence in the normal volunteers and in patients with functioning transplanted kidneys and acute tubular necrosis. Partial or total loss of corticomedullary differentiation was seen in glomerulonephritis, acute and chronic renal failure, renal artery stenosis, and transplant rejection. The T1 of the kidneys was increased in glomerulonephritis with nephrotic syndrome, but the T1 was within the normal range for renal medulla in glomerulonephritis without nephrotic syndrome, renal artery stenosis, and chronic renal failure. A large staghorn calculus was demonstrated with MRI, but small calculi were not seen. Fluid within the hydronephrosis, simple renal cysts, and polycystic kidneys displayed very low signal intensity and long T1 values. Evidence of recent hemorrhage into cysts was seen in polycystic kidneys. Tumors displayed varied appearances. Hypernephromas were shown to be hypo- or hyperintense with the renal medulla on the IR 1400/400 sequence. After intravenous injection of gadolinium-DTPA, there was marked decrease in the tumor T1.

Adolescent↗

PubMed1989

MR appearance of gallstones in vitro at 1.5 T: correlation with chemical composition.

Gallstones from 63 patients were evaluated by in vitro 1.5-T MR imaging, with T1- and T2-weighted images, and in 14 cases, a fat-suppression sequence (short-T1 inversion recovery imaging). Subsequent chemical analysis was performed on 43 gallstones. In vitro proton MR spectroscopy was performed on 14 stones. On T1-weighted MR images, foci of increased signal were seen in 46 of 63 stones (faint in 17, moderate in nine, and bright in 20). T2-weighted images showed areas of increased signal in 18 of 63 stones (faint in 15, moderate in three). T1-weighted MR imaging patterns were homogeneously dark (17), homogeneously bright (two), homogeneously faint (three), rimmed (dark rim and bright center, 32), and laminated (nine). Short-T1 inversion recovery imaging suppressed the foci of increased signal in 13 of 14 cases. Despite imaging characteristics suggestive of high lipid content, spectroscopy revealed only a single peak corresponding to a large water-proton signal. The T1 relaxation times of the water were shortened, ranging from 0.006 to 0.92 sec, explaining the increased signal seen on MR images of the gallstones. MR imaging characteristics (signal intensity, relative signal area, or imaging patterns) did not correlate with chemical composition. We hypothesize that different structural relationships must exist within gallstones of similar chemical content that alter the water bonding and hence the MR imaging characteristics.

Cholelithiasis↗

PubMed1990

Detection of malignant bone tumors: MR imaging vs scintigraphy.

One hundred six patients with a known or suspected diagnosis of bone cancer (11 patients with biopsy-proved primary tumors, 95 patients with metastatic disease) were evaluated with scintigraphy and MR imaging to determine the relative sensitivity of each technique in the detection of bone disease. MR imaging was performed at 0.5 T as part of the entry evaluation into Intramural Research Board protocols (30%), for evaluation of cord compression, or because of an equivocal scintigram. MR was performed with T1-weighted (e.g., 300-500/10-20 [TR/TE]), T2-weighted (e.g., 2000/80) spin-echo (SE), and a short-TI inversion recovery (STIR) pulse sequence. Scintigrams were performed with 99mTc-methylene diphosphonate. A retrospective analysis showed that in 30 (28%) of 106 patients, MR imaging performed over a limited region of interest revealed a focal abnormality consistent with tumor that was not observed on scintigraphy. Only one patient had an abnormality on scintigraphy, caused by a metastasis, that was not found on MR images. In 73 (69%) of the 106 patients, the results of MR imaging and scintigraphy were equivalent; in 41 cases results of both techniques were normal. A McNemar analysis of the discordant cases showed MR imaging to be more sensitive than scintigraphy was (p less than .001). Our results suggest that although MR imaging has a greater sensitivity in detecting focal disease, scintigraphy is still the most useful screening test for evaluating the entire skeleton. MR imaging should be reserved for clarification of scintigraphic findings when suspicion is high for tumor.

Adolescent↗

PubMed1992

Visceral metastases from melanoma: findings on MR imaging.

Typical ocular and CNS melanomas are hyperintense on T1-weighted MR images and hypointense on T2-weighted MR images. We performed MR imaging in 48 patients with melanoma metastatic to visceral organs. Images were reviewed retrospectively in order to determine whether there were predominant MR features specific for visceral melanoma and to see if visceral metastases have MR characteristics similar to metastases in the CNS. Eleven patients also were examined after injection of gadopentetate dimeglumine to evaluate the enhancement characteristics of these tumors. Two hundred sixty-one lesions were found. Lesions were classified according to their signal intensities relative to uninvolved liver on T1-weighted, T2-weighted, and short TI inversion recovery (STIR) pulse sequences. Most commonly, lesions were either hypointense or isointense on T1-weighted sequences and hyperintense on T2-weighted and STIR sequences (185 lesions). Less frequently, lesions were hyperintense on T1-weighted sequences and hypointense or isointense on T2-weighted and STIR sequences (59 lesions). A mixed pattern was seen on T1- and T2-weighted sequences in 17 lesions. The patterns did not correlate with lesion size. Of the three sequences studied by subjective comparison, the STIR sequence in our series had the highest sensitivity for lesion detection and yielded the highest lesion conspicuity. Injection of gadopentetate dimeglumine in 11 patients did not increase either the number or the conspicuity of lesions seen. Our results show that visceral metastases from melanoma have a wide variety of appearances on MR images. The STIR sequence appears to be optimal, and the metastases do not enhance with gadopentetate dimeglumine.

Abdominal Neoplasms↗

PubMed1998

MR imaging in children with nonperforated acute appendicitis: value of unenhanced MR imaging in sonographically selected cases.

OBJECTIVE: The aim of this study was to describe the MR appearance of acute appendicitis and to determine the value of MR imaging for diagnosis of acute appendicitis. SUBJECTS AND METHODS: Forty-five children (28 girls, 17 boys), 7-16 years old (mean age, 13 years old), with clinically diagnosed acute appendicitis underwent independently graded compression sonography by two radiologists. MR imaging was performed when sonography revealed acute appendicitis (observer 1, 16 [36%] patients; observer 2, 18 [40%] patients), was inconclusive (observer 1, two [4%] patients; observer 2, one [2%] patient), and was interpreted as normal (observer 1, two [4%] patients; observer 2, one [2%] patient) (n = 20). Axial T1-weighted turbo spin-echo sequences, T2-weighted turbo spin-echo sequences in the axial and coronal planes, and fat-suppressed short inversion time inversion recovery turbo spin-echo sequences in the axial plane (4-mm slice thickness) were obtained and evaluated independently by two radiologists. The ability to see acute appendicitis with MR imaging was evaluated, the appearance and morphologic changes were described, and the most accurate sequence was determined. All children in whom MR imaging was performed underwent surgery. RESULTS: MR imaging revealed acute appendicitis in all cases (100%) by both observers. On T2-weighted ultra turbo spin-echo images, acute appendicitis appeared with a markedly hyperintense center, a slightly hyperintense thickened wall, and markedly hyperintense periappendiceal tissue. Unenhanced axial T2-weighted spin-echo imaging was the most sensitive sequence. CONCLUSION: In this study group, MR imaging was a valuable technique for depiction of acute appendicitis.

Acute Disease↗

PubMed2005

Myocardial late enhancement in contrast-enhanced cardiac MRI: distinction between infarction scar and non-infarction-related disease.

OBJECTIVE: Our objective was to assess and compare the patterns of late enhancement (LE) in contrast-enhanced cardiac MRI caused by myocardial infarction and different myocardial diseases that are not related to ischemic infarction. MATERIALS AND METHODS: A total of 811 consecutive contrast-enhanced cardiac MRI studies performed for different indications were reviewed for left ventricular myocardial LE after gadopentetate dimeglumine administration. MRI studies were performed on a 1.5-T scanner using an inversion recovery turbo FLASH sequence (TR/TE, 8/4 msec; flip angle, 25 degrees). The LE pattern of ischemic infarction scar was compared with that in nonischemic myocardial disease. RESULTS: LE was found in 421 (52%) patients. In all patients with myocardial infarction, LE included the subendocardial layer. Nineteen patients without history of myocardial infarction and angiographically excluded coronary artery disease showed different patterns of LE caused by myocarditis, sarcoidosis, arrhythmogenic right ventricular dysplasia, cardiomyopathy, endomyocardial fibrosis, and iatrogenic scars after biopsy, ablation of septal hypertrophy, and myocardial laser revascularization. CONCLUSION: LE in contrast-enhanced cardiac MRI is not specific for ischemic infarction. LE in ischemic infarction always involves the subendocardial layer, whereas it does not necessarily do so in other myocardial diseases. Therefore, if LE omit the subendocardial layer, different nonischemic myocardial diseases have to be considered. The pattern of LE might be helpful for the differential diagnosis of myocardial disease and in distinguishing it from ischemic disease.

Adult↗

PubMed2000

Polymorphism of the rabbit kappa kasein gene and its influence on performance traits.

The rabbit kappa-casein encoding gene has previously been shown to possess two alleles. The two alleles do not differ in their coding region and in the accumulation levels of mRNA. However they differ greatly with respect to their intronic regions. The rearranged regions in the first and fourth introns were found to be inverse and complementary LINE sequences. The A allele was found to be more frequent in different European breeds. Correlation of the kappa-casein genotype with the breeding capacity in a New Zealand White rabbit stock has been examined.

Alleles↗

PubMed2000

Diffusion-weighted magnetic resonance imaging in a case of methanol intoxication.

BACKGROUND: Methanol intoxication is an uncommon clinical problem leading to profound metabolic acidosis with serious neurological deterioration. We describe methanol induced brain lesions on diffusion-weighted MR images and discuss the pathophysiology of these lesions in light of diffusion changes. CASE REPORT: Brain imaging was performed in a 32 year-old man in a coma with focal neurological signs. Bilateral putaminal [hyperintensity] was seen on fast spin echo T2-weighted sequences, on Fluid Attenuated Inversion Recovery (FLAIR) and on diffusion weighted images. Decreased ADC values were observed bilaterally in the putamina. In addition, FLAIR images showed diffuse hypersignal in the subarachnoidal space. The patient showed rapid neurological deterioration while blood chemical tests revealed a severe metabolic acidosis and plasma methanol levels of 21 mmol/L. The patient died from hepatic failure thirty six hours after admission. CONCLUSION: Although decreased ADC values on diffusion-weighted imaging are commonly associated with arterial ischemic stroke, this pattern can also be observed in the case of putaminal necrosis following methanol ingestion.

Adult↗

PubMed2000

V(D)J recombinase-mediated transposition of the BCL2 gene to the IGH locus in follicular lymphoma.

Using DNA fiber fluorescence in-situ hybridization (FISH) and 3-color interphase FISH, 2 cases of follicular lymphoma were identified in which the BCL2 gene was excised from 18q21 and inserted into the immunoglobulin heavy chain (IGH) locus at 14q32. Both the insertion breakpoint at 14q32 and the deletion breakpoint at 18q21 were cloned using inverse polymerase chain reaction. Sequence analysis showed that the JH sequences were juxtaposed to the 5'-side of BCL2, and the DH sequences were juxtaposed to the 3'-side of BCL2. There were breakpoints at both the JH and DH recombination signal sequences, and N-nucleotides were present at all breakpoint junctions. At the BCL2 locus, the 3'-breakpoints in both cases were localized at exactly the same nucleotide position, 6. 2 kilobase downstream of the major breakpoint region, directly adjacent to a complete cryptic recombination signal sequence (RSS) consisting of a heptamer, a nonamer, and a 23-base pair (bp) spacer. The BCL2 5'-breakpoints were approximately 600 bp upstream of the gene, within the CA repeats. Although less evident than for the BCL2 3'-breakpoints, cryptic RSSs were also identified at these breakpoints, with a 12-bp spacer. On the basis of structural characteristics of these rearrangements, a model is proposed in which the BCL2 gene is deleted from its locus by recombination activation gene-1/-2 (RAG-1/-2)-mediated excision. The gene is subsequently inserted into the recombining IGH locus, a process involving the formation of hybrid joints between the IGH coding ends and the BCL2 signal ends. (Blood. 2000;96:1947-1952)

Base Sequence↗

PubMed2002

[MRI exploration of partial epilepsy].

Investigative strategies for partial epilepsy have evolved greatly since the advent of morphological MRI. MRI currently provides the most extensive and sensitive information for detecting and localizing brain anomalies. Technical progress has included new sequences (3D acquisition, inversion-recovery, fast spin-echo), new imaging planes (through the greater diameter of the hippocampus for temporal epilepsy, orbitao-meatal for extra-temporal epilepsy), high-resolution imaging, and better signal-noise ratio in addition to new procedurs such as NMR spectroscopy, diffusion/perfusion imaging, or functional MRI. One of the principal aims of MRI is to detect potentially epileptogenic brain anomalies useful for the detection and localization of the epileptic focus. MRI sensitivity is much greater than brain computed tomography, which excepting specific cases, is no longer contributive. Hippocampal sclerosis is a typical example of an epilepsy-related brain anomaly (mesial temporal lobe epilepsy) whose diagnosis has been changed by MRI. This entity was described by Bouchet and Cazauvieilh in 1825 who related anatomic postmortem findings to the clinical expression. Reliable diagnosis of hippocampal sclerosis can now be achieved with MRI, contributing to the diagnosis of mesial temporal lobe epilepsy. MRI can also contribute precious prognostic information, useful for both drug and surgical treatment. It has been demonstrated that the degree of response to drug treatment is not univocal and that certain lesions such as hippocampal sclerosis are generally associated with drug resistance. Sensitivity to drug therapy also varies with the type of cerebral dysgenesia. It has also been demonstrated that the a brain lesion identified at MRI is generally a factor of good prognosis after surgery. Continuing improvements in MRI techniques, widespread availability of technical facilities and new derived techniques contribute greatly to the usefulness of MRI for investigating partial epilepsy.

Anticonvulsants↗

PubMed2002

Sequential MR imaging of denervated muscle: experimental study.

BACKGROUND AND PURPOSE: MR changes in denervated muscles have been reported to occur within days up to several weeks after peripheral nerve damage. The purpose of this experimental study was to investigate the longitudinal changes in denervated muscles by using MR imaging. METHODS: In 12 Lewis rats, the left sciatic nerve was transected at the level of the proximal thigh. MR imaging of both legs was performed before and 1 hour, 24 hours, 48 hours, 7 days, 14 days, 28 days, and 2 months after the procedure. The MR protocol included T1-weighted spin-echo, T2-weighted double turbo spin-echo, and turbo inversion recovery magnitude (TIRM) sequences obtained in the axial plane. Signal intensities (T2-weighted double turbo spin-echo and TIRM sequences) and the T2 TR (T2-weighted double turbo spin-echo sequence) were recorded for the soleus, peroneal, and gracilis muscles of both sides. Moreover, the circumferences of both lower legs were determined on the basis of T1-weighted images. RESULTS: Twenty-four hours after denervation, a signal intensity increase in the denervated peroneal and soleus muscles was present on TIRM images. On T2-weighted images, only the peroneal muscle exhibited slightly increased signal intensities and T2 TR. Forty-eight hours after nerve transection, the denervated soleus and peroneal muscles revealed prolonged T2 TR and marked increased signal intensities on T2-weighted and TIRM images when compared with the contralateral side, which further increased at or less than 2 months after denervation. Muscle atrophy of the denervated muscles was present as early as 7 days after denervation and was also increased at follow-up examinations. CONCLUSION: The TIRM sequence is more sensitive than is T2-weighted imaging in the detection of signal intensity changes in denervated muscle. These changes occur as early as 24 (TIRM sequence) and 48 (T2-weighted sequence) hours, respectively, after complete transection of the sciatic nerve in rats and precede muscle atrophy. The sensitivity to early signal intensity changes in denervated muscles may support the use of MR imaging in the diagnosis of peripheral nerve lesions.

Animals↗

PubMed2003

Ultrasound detection of heel enthesitis: a comparison with magnetic resonance imaging.

OBJECTIVE: Seronegative arthropathies are associated with inflammatory enthesopathy. The involvement of Achilles tendon and plantar aponeurosis is common, with strong tendency toward fibrosis and calcification. This study tests the diagnostic efficacy of ultrasound (US) in depicting enthesitis, and compares sonographic images with magnetic resonance images (MRI). METHODS: We studied 32 patients with a diagnosis of seronegative arthropathies, 22 men, 10 women, mean age 29 years. They had heel enthesopathy without typical conventional radiographic evidence. T1 and T2 weighted and short-tau inversion recovery (STIR) MRI sequences were obtained in axial and sagittal planes. An HDI 3000 ATL US device equipped with 12 MHz linear transducer was used to examine the enthesis. Three independent observers assessed the reliability of sonographic images by using video recording of the US examinations. RESULTS: US images of enthesitis showed loss of normal fibrillar echotexture of tendon (100%), lacking the homogeneous pattern, with blurring of tendon margins (56.2%) and irregular fusiform thickening (84.3%). The affected tendons showed intratendinous lesions with ill defined focal tendon defects filled with a mixture of fluid, fat, and/or granulation tissue, with loss of their tightly packed echogenic dots. MRI showed tendon enlargement (62.5%) with loss of the normal flattened hypointense appearance, focal thickening and rounded configuration at the insertion site (31.2%), intermediate T1 and high T2 signals, and diminished signals within the pre-Achilles fat pad due to inflammatory edema. Among all patients, 40.6% developed osteitis. CONCLUSION: MRI was not sensitive compared to US in detecting early changes of enthesopathy. Fatty degeneration appeared late in MRI, while it was detected earlier using US. MRI was not able to detect any calcification process at the insertion site, while US images clearly showed the very early signs of the calcification process. We recommend use of US for early diagnosis and in treatment and followup of patients with tendon enthesopathy, to accurately identify and diagnose different pathologic and biomechanical changes.

Achilles Tendon↗

PubMed2003

MR imaging in the differential diagnosis of neurogenic foot drop.

BACKGROUND AND PURPOSE: Prolonged T2 relaxation time of denervated muscle has been described in several clinical and experimental studies. The purpose of this study was to evaluate the utility of MR imaging in the diagnosis of neurogenic muscle disorders compared with that of clinical and electrophysiologic examination. METHODS: In a prospective study, 40 consecutive patients clinically presenting with a foot drop were included. MR imaging of the lower leg included axial T1-weighted and axial turbo inversion recovery magnitude (TIRM) sequences. Two readers blinded to clinical data evaluated T1-weighted images for anatomic localization of affected muscles and TIRM images for patterns of signal intensity increase. After MR imaging, a detailed neurophysiologic examination was performed. Cause of foot drop was independently determined on the basis of MR and electrophysiologic data. RESULTS: Clinical examination and electromyography (EMG) disclosed 20 peroneal nerve lesions, nine cases of L5 radiculopathy, and 11 nerve lesions extending beyond neural structures. MR imaging revealed three distinct patterns of signal intensity increase on TIRM images: peroneal nerve pattern, L5 pattern, and unspecific pattern. MR imaging and EMG findings were in agreement in 37 (92%) of 40 patients. In three patients, MR imaging revealed a more widespread involvement than did EMG. In one of these patients, denervation in the corresponding muscle was validated by follow-up EMG. No false-negative diagnoses were made by use of MR imaging as compared with use of EMG. CONCLUSION: MR imaging improves accuracy in the differential diagnosis of peripheral nerve lesions compared with that of EMG and can supplement EMG in the diagnosis of denervated muscles.

Action Potentials↗