3.0 T conventional hip MR and hip MR arthrography for the acetabular labral tears confirmed by arthroscopy

Objective

To evaluate the value of hip MR for diagnosing acetabular labrum tears, and to further compare the diagnostic performances of conventional MR with MR arthrography in acetabular labrum tears.

Methods

90 patients undergoing both hip MR examination and subsequent hip arthroscopy were retrospectively evaluated. Of these patients, 34 accepted both conventional MR and MR arthrography; while the other 56 only underwent conventional MR examination. All hip MR images were independently reviewed by two radiologists, and further compared with the results of hip arthroscopy.

Results

59 of 90 patients were confirmed with acetabular labral tears by hip arthroscopy and 31 without tears. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of conventional MR for evaluating the acetabular labral tears were 61.0%, 77.4%, 83.7% and 51.1% (radiologist A), and 66.1%, 74.2%, 82.9% and 53.4% (radiologist B), respectively, with good consistency between the two observers (K = 0.645). The sensitivity, specificity, PPV and NPV of MR arthrography for assessing the acetabular labral tears were 90.5%, 84.6%, 90.5% and 84.6% (radiologist A), and 95.2%, 84.6%, 90.9% and 91.7% (radiologist B), respectively, with excellent good consistency between the two observers (K = 0.810). The sensitivity and NPV of MR arthrography for diagnosing the acetabular labral tears were significantly higher than those of conventional MR (both P < 0.05).

Conclusion

Hip MR arthrography is a reliable evaluation modality for diagnosing the acetabular labral tears, and its diagnostic performance is superior to that of conventional MR at 3.0 T.     

3.0T常规MRI与MR髋关节造影诊断髋臼唇撕裂的对比研究

目的 在3.0 T场强中,比较常规髋关节MRI及MR髋关节造影对髋臼唇撕裂的诊断价值.方法 回顾分析44例髋关节病变患者的患侧髋关节常规MRI及MR髋关节造影资料,将每例患者的臼唇划分为前、上、后3处区域(共计132处),确定有无撕裂,并进行分型.其中5例患者经髋关节镜检查.对于常规MRI及MR髋关节造影获得的臼唇撕裂及分型数据差异比较采用Wilcoxon秩和检验,一致性比较采用Kappa检验.结果 常规MRI与MR髋关节造影诊断完全相同者计116处臼唇,只有16处存在诊断差异.其中,前者诊断无撕裂而后者诊断撕裂者9处,前者诊断撕裂但后者诊断无撕裂者6处,其余1处两者均诊断为撕裂但分型不同.常规MRI与MR髋关节造影的评价差异没有统计学意义(Z=0.347,P＞0.05),且具有极好的一致性(K=0.781,P＜0.01).在接受关节镜的5例患者中,常规MRI、MR髋关节造影及关节镜结果均完全吻合.结论 对髋臼唇撕裂,3.0 T常规髋关节MRI可获得与MR髋关节造影基本相同的诊断效果.     

Diagnostic efficacy in knee MRI comparing conventional technique and multiplanar reconstruction with one-millimeter FSE PDW images

Background: Magnetic resonance (MR) imaging has proved to be an excellent tool in diagnosing injuries of the cruciate ligaments and menisci. However, multiple planes and sometimes optimal oblique or double-oblique scan planes are needed due to the variability in the positioning of important structures, which means there is a lower throughput and longer scanning time.

Purpose: To compare the performance of a 1-mm-thickness fast spin-echo (FSE) proton-density-weighted (PDW) MR imaging technique with multiplanar reconstruction (MPR) in diagnosing tears of the menisci and cruciate ligaments with that of conventional MR imaging.

Material and Methods: Twenty-five consecutive patients underwent preoperative conventional and 1-mm-thickness FSE PDW MR imaging with subsequent knee arthroscopic surgery. Two musculoskeletal radiologists evaluated the status of the cruciate ligaments and menisci using two sets of MR images (method A: conventional images including seven sequences, taking 26 min; method B: 1-mm-thickness FSE PDW images with MPR, taking 7 min 20 s). The diagnostic efficacies of both methods for tears of the cruciate ligament and menisci were calculated and compared.

Results: Arthroscopic surgery revealed 10 anterior cruciate ligament (ACL) tears, one posterior cruciate ligament (PCL) tear, and 26 meniscal tears. The diagnostic values of both methods were 100% for a cruciate ligament tear. The diagnostic values (sensitivity, specificity, accuracy, positive predictive value, and negative predictive value) for meniscal tears were 90%, 100%, 96%, 100%, and 94% for method A, and 95%, 100%, 98%, 100%, and 97% for method B, respectively. There were no significant differences in the diagnostic values between methods A and B.

Conclusion: 1-mm-slice-thickness FSE PDW imaging with MPR showed comparable performance in diagnosing tears of the cruciate ligaments and menisci to conventional sequences but the scan time was much shorter. Therefore, this technique (method B) might improve the throughput of a 3T MR imaging system.     

Anterior dynamic ultrasound and Graf's examination in neonatal hip instability

Background: Discrepancy between neonatal hip morphology and stability has been reported in the literature. Comparative ultrasound studies on this issue are limited.

Purpose: To compare neonatal hip instability, as assessed by dynamic ultrasound and clinical examination, with acetabular morphology, as assessed by Graf's method.

Material and Methods: 536 newborn infants with clinical signs of hip instability, ambiguous findings at clinical hip examination, or positive risk factors for DDH were investigated with two ultrasound methods, the Graf method and anterior dynamic ultrasound, at an average age of 12 days. The hips were allocated to three groups according to the Graf result: A, normal (type Ia and b); B, borderline or immature (type IIa); and C, pathologic (type IIc and worse). Graf examination was compared with two diagnostic tests for instability, namely clinical examination by senior pediatric orthopedists and anterior dynamic ultrasound.

Results: According to Graf's method, 77% of the hips were normal, 20% borderline/immature, and 3% pathologic. On clinical hip examination, 82% were stable, 14% unstable, and 4% dislocatable. The dynamic ultrasound outcome was 88% stable hips, 10% unstable, and 2% dislocatable. Of the hips considered unstable or dislocatable on dynamic ultrasound, 21% had normal (type I) and 66% immature acetabular morphology according to the Graf method. Of the hips that were stable on dynamic ultrasound, only one (0.1%) was dysplastic according to the Graf method. Graf's examination showed the smallest number of normal hips, but also the fewest pathologic hips, with many indeterminate results that needed follow-up.

Conclusion: Acetabular morphology correlated better to stability as assessed by dynamic ultrasound than to the clinical examination results, with fair to moderate agreement. Graf's examination resulted in a large number of indeterminate results that needed follow-up, but when used as the sole criterion for deciding treatment did not lead to a higher treatment rate than when the decision was based on clinical hip examination.     

Comparison of 3.0-T MR vs 3.0-T MR arthrography of the hip for detection of acetabular labral tears and chondral defects in the same patient population

Objective:

We report our experience in diagnostic sensitivity of 3.0-T conventional MR vs 3.0-T MR arthrography of the hip for detection of acetabular labral tears and chondral defects in the same patient population.

Methods:

43 consecutive patients had both conventional hip MR and MR arthrography examinations performed. These examinations were reviewed retrospectively by independent reading of two musculoskeletal radiologists who read the MR and MR arthrogram examinations in a randomized fashion (i.e. MR and MR arthrogram examinations were read at separate sittings and in a randomized fashion so as not to bias reviewers). Scans were assessed for acetabular labral tears and chondral defects. All patients went on to arthroscopy.

Results:

Of these 43 patients, 40 had acetabular labral tears read by Reader 1 and 39 had acetabular labral tears read by Reader 2 on MR arthrogram, 39 had acetabular labral tears read by Reader 1 and 38 had acetabular labral tears read by Reader 2 on conventional MR examination. There were 42 labral tears in 43 patients at arthroscopy. There were four false-negative labral tears compared with arthroscopy on MR and three false negatives on MR arthrography for Reader 1 and five false negatives on MR and four false negatives on MR arthrography for Reader 2. Each reader had one false-positive labral tear compared with arthroscopy on both MR and MR arthrography. There were 32 acetabular chondral defects at arthroscopy. Reader 1 saw 21 acetabular chondral defects on conventional MR and 27 chondral defects at MR arthrography. Reader 2 saw 19 acetabular chondral defects at conventional MR and 25 acetabular chondral defects on MR arthrography. There were no false-positive readings of chondral defects compared with arthroscopy on MR and one false positive for Reader 1 and two false positives for Reader 2 on MR arthrography as compared with arthroscopy. On conventional MR examination, sensitivities and specificities as compared with arthroscopy were as follows: Reader 1 acetabular labral tear (90% sensitivity, 0% specificity) and Reader 2 acetabular labral tear (88% sensitivity, 0% sensitivity). On MR arthrogram, sensitivities and specificities as compared with arthroscopy for Reader 1 were 93%, 0% and for Reader 2 were 90%, 0%, respectively. Sensitivities and specificities for detection of acetabular chondral defects as compared with arthroscopy were Reader 1 conventional MR (65% sensitivity, 100% specificity), Reader 1 MR arthrography (81% sensitivity, 91% specificity), Reader 2 conventional MR (59% sensitivity, 100% specificity) and Reader 2 MR arthrography (71% sensitivity, 82% specificity).

Conclusion:

In this series, 3.0-T MR demonstrated sensitivity for detection of acetabular labral tears that rivals the sensitivity of 3.0-T MR arthrography of the hip. In this series, 3.0-T MR arthrography was more sensitive than conventional 3.0-T MR for detection of acetabular chondral defects.

Advances in knowledge:

3.0-T MR and MR arthrography are near equivalent in the diagnosis of acetabular labral tears. This information is useful for pre-operative planning.MR arthrography has been reported to be more sensitive and specific for detection of acetabular labral tears in the hip than conventional MRI.^1–10 MR arthrography has also been reported to be superior in detection of acetabular cartilage defects as compared with conventional MRI.¹¹ To our knowledge 3.0-T MR vs 3.0-T MR arthrography sensitivity for detection of acetabular labral tears and chondral defects has not been specifically assessed.To our knowledge, Petersilge et al¹ first reported the utility of hip MR arthrography in the diagnosis of acetabular labral tears. Toomayan et al² compared MR arthrography of the hip with conventional MRI of the hip in different patient populations. He found MR arthrography with a small field of view to be substantially more sensitive for detection of acetabular labral tears than conventional MRI. Sutter et al¹¹ found 1.5 T MR arthrography to be superior to conventional MRI for detecting labral tears and acetabular cartilage defects.Patients with acetabular labral tears present with symptoms of persistent pain, clicking, locking and decreased range of motion. With the availability of hip arthroscopy, labral tears can more easily be addressed with minimally invasive surgery. Accurate pre-operative identification of labral tears is needed.² Based on previous studies demonstrating the accuracy of MR arthrography in detection of acetabular labral tears, surgeons often request MR arthrography of the hip to characterize labral tears prior to surgery.^1–10 The purpose of this study is to assess 3.0-T MR vs MR arthrography diagnostic performance in detection of acetabular labral tears and chondral defects in the same patient population using arthroscopy as a reference standard.     

髋关节MR造影在髋臼唇撕裂诊断中的应用

目的 探讨髋关节MR造影在髋臼唇撕裂诊断中的应用价值.方法 临床高度怀疑髋臼唇撕裂的15例20个髋关节在透视下行髋关节穿刺造影,采用SE T1WI加脂肪抑制技术,进行髋关节冠状面、矢状面、斜轴面及放射状位扫描.其中12例行关节镜检查.结果 在行髋关节镜检查的12例14个髋关节中,11例13个髋关节MR造影诊断为髋臼唇撕裂,与关节镜诊断相符;1例MR造影示正常,关节镜检查亦未发现髋臼唇撕裂.13个髋臼唇撕裂中位于前上象限12个髋关节,后上象限1个髋关节.在关节镜诊断髋臼唇撕裂的13个髋关节中,MR造影冠状面诊断髋臼唇撕裂3个髋关节,矢状面诊断10个髋关节,斜轴面及放射状位诊断髋臼唇撕裂均为13个髋关节.15例20个髋关节中有5例6个髋关节在后下象限有髋臼唇下沟表现.结论 MR髋关节造影是诊断髋臼唇撕裂的可靠方法,扫描方法应选择T1WI加脂肪抑制的矢状面及斜轴面或矢状面加放射状位.后下象限撕裂的诊断中应注意正常变异的存在.

Abstract：

Objective To investigate the application value of MR rthrography (MRA) in the diagnosis of acetabular labral tears. Methods Fifteen patients with a high degree of suspected acetabular labral tears received fluoroscope-guided injection of the contrast media into the hip joint ( hip arthrography) and fat-saturated spin-echo T1-weighted images were obtained in the coronal, sagittal, oblique-axial and radial planes. Hip arthroscopy was performed on 12 of them. Results Labral tears which were diagnosed in 11 patients by hip MRA were confirmed at hip arthroscopy. One patient showed no MRA indication of labral tear, also showed normal on arthroscopy. Tear in the anterior-superior quadrant 10 cases of 12 joints ( 12/13), posterior-superior quadrant 1 case of a joint (1/13). In 11 patients who underwent arthroscopy, hip MRA diagnosed 3 (3/13) joints labral tears in coronal planes, 10 (10/13) joints in sagittal planes and 13 (13/13) labral tears in axial-oblique and radial planes. In 15 patients with 20 hip joints, 5 cases 6 joints (6/20) with normal acetabular sublabral sulcus were performed. Conclusions MR arthrography of hip is a reliable method in the diagnosis of acetabular labral tears. Scanning method should be included fat-saturated spin-echo T1-weighted images in sagittal and oblique-axial planes or sagittal plus radial planes. The diagnosis of tor posterior-inferior quadrant should pay attention to the existence of a normal variation.     

Comparison study of intraarticular and intravenous gadolinium-enhanced magnetic resonance imaging of cartilage in a canine model

Background: Magnetic resonance (MR) imaging and measurement of glycosaminoglycan (GAG) have potential for characterization of hyaline articular cartilage. Recently, some reports have demonstrated the potential of direct administration of contrast media for MR imaging of cartilage.

Purpose: To prove the feasibility of intraarticular gadolinium-enhanced MR imaging of cartilage (iGEMRIC) and T1 relaxation mapping of the articular cartilage in vivo with intraarticular injection of Gd-DTPA^2-.

Material and Methods: Five healthy beagle dogs underwent MR imaging and T1 relaxation mapping of the knee joints of both hind legs. The delayed gadolinium-enhanced MR imaging of cartilage (dGEMRIC) and iGEMRIC techniques were interchanged with MR imaging. For dGEMRIC, a double routine dose of Gd-DTPA^2- (0.2 mM/kg) was administered intravenously. For iGEMRIC, 2.5 and 1.25 mmol/l saline-diluted Gd-DTPA^2- solutions were separately injected into the right and left knee joints, respectively, prior to MR imaging. Color-coded T1 maps of 20 femoral condyles were obtained from the dGEMRIC and iGEMRIC images. The signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and glycosaminoglycan (GAG) delineation of articular cartilage were compared between the dGEMRIC and iGEMRIC techniques.

Results: The mean SNR was higher with dGEMRIC than with iGEMRIC, but the difference was not statistically significant (P = 0.174). The mean (±SD) CNR was higher with iGEMRIC (-11.6±3.4) than with dGEMRIC (-16.7±4.0; P = 0.000), although the absolute value of the CNR was higher with dGEMRIC. The layering and gradient distribution of GAG were more clearly visualized on the iGEMRIC images. The mean scores of GAG delineation with dGEMRIC and iGEMRIC were 0.7±0.6 and 2.2±1.7, respectively. The iGEMRIC method better visualized GAG distribution (P = 0.001).

Conclusion: Although the SNR did not differ significantly between the iGEMRIC and dGEMRIC techniques, the color-coded T1 map produced with iGEMRIC allowed better cartilage evaluation. Thus, iGEMRIC exhibits the useful features of both MR arthrography and dGEMRIC, and provides a color-coded T1 map that is useful for diagnosing early articular cartilage damage.     

Neonatal hip instability: a prospective comparison of clinical examination and anterior dynamic ultrasound

Background: Ultrasound is increasingly being used to complement the clinical examination in assessing neonatal hip instability. The clinical examination, although highly sensitive in detecting hip instability, can lead to considerable overtreatment.

Purpose: To compare anterior dynamic ultrasound and clinical examination in the assessment of neonatal hip instability and regarding treatment rates.

Material and Methods: 536 newborn infants (out of a population of 18,031) were selected, on the basis of a combination of risk factors, clinical signs of hip instability or ambiguous clinical findings, to undergo an anterior dynamic ultrasound examination of the hip, by a method developed by our group. This examination, performed by one out of seven experienced examiners, was compared with the standard clinical hip examination conducted by one of four pediatric orthopedic surgeons. The clinical examination was carried out both prior to and within a few hours after the ultrasound examination.

Results: The clinical examination diagnosed 81.7% of the hips as normal, 14.5% as unstable, and 3.8% as dislocatable or dislocated. With the dynamic ultrasound method, the corresponding figures were 87.8%, 10.4%, and 1.8%, respectively. Use of the criteria of the clinical examination resulted in treatment of 147 infants. Using the dynamic ultrasound examination as a criterion meant that 87 infants would receive treatment. The calculated treatment rate was 0.85% when based on the clinical stress test and 0.49% when based on the dynamic ultrasound.

Conclusion: The dynamic ultrasound results reduced the treatment rate by over 40% when used as a basis for the decision regarding treatment.     

Arthroscopic treatment of labratears

The acetabular labrum serves important physiological and biomechanical functions, allowing for normal hip function. Tears of the acetabular labrum occur in active, young patients. Common injuries attributed to labral tears include direct blows, falls, twisting injuries, and running. In many patients, however, the onset of symptoms is insidious, with atraumatic tearing caused by repetitive activities. These injuries, in most cases, may be diagnosed through careful history, physical examination, and magnetic resonance (MR) arthrography. A small subset of patients may respond to conservative treatment when initiated early. Arthroscopy of the hip is the gold standard both for diagnosing and treating labral tears. By using careful techniques and arthroscopic instrumentation adapted for the hip, arthroscopic treatment of labral tears may be performed with a very low rate of complications and successful treatment of symptoms in the majority of patients. However, long-term outcomes after partial labrectomy are not known.     

Is subcutaneous local anesthesia in shoulder magnetic resonance arthrography necessary?

Background: Magnetic resonance arthrography is a well-established diagnostic method in degenerative and traumatic disorders of the shoulder. Some radiologists prefer to apply a local anesthetic to the skin prior to performing the joint puncture. However, no information regarding the efficacy of local anesthetics exists.

Purpose: To assess patient discomfort in arthrography injection.

Material and Methods: A patient survey (n = 74) utilizing a visual analog scale (VAS) measured the intensity of pain in arthrography injection by those receiving local anesthetics (n = 36) versus those who did not (n = 38).

Results: Mean VAS scores were 20.8 (median 10.5, SD 24.3) for those receiving local anesthetics versus 19.3 (median 13.0, SD 20.7) for those who did not (P = 0.83, Mann-Whitney U test).

Conclusion: Routine use of local anesthesia of the skin in arthrography injection is unnecessary.     

Detection and characterization of focal liver lesions with contrast-enhanced ultrasonography in patients with hepatitis C-induced liver cirrhosis

Background: Hepatitis C virus (HCV)-associated liver cirrhosis provides a major preneoplastic condition for hepatocellular carcinoma (HCC). Ultrasonography (US) is usually used for screening of HCC, but needs improvement.

Purpose: To assess whether use of a second-generation ultrasound contrast agent can improve characterization of focal liver lesions and detection of HCC in HCV-infected patients with liver cirrhosis.

Material and Methods: In total, 96 US studies in 49 HCV-infected patients with liver cirrhosis were performed. The patients were first examined with a baseline US. After this, a diagnostic decision was made and recorded. The patients were then re-examined with contrast-enhanced ultrasound (CEUS), and the diagnostic triage was repeated. The patients were followed up for at least 1 year.

Results: On baseline US, indeterminate focal lesions were found in 27 examinations. After CEUS, a confident diagnosis of HCC was made in eight of these examinations. In an additional eight US examinations, diagnosis of regenerative/dysplastic noduli was established. In one patient with no detectable focal lesion at baseline examination, an indeterminate malignant lesion was detected with CEUS. This lesion was further investigated with computed tomography and diagnosed as HCC.

Conclusion: Our study indicates that the use of CEUS significantly improves diagnostic confidence. CEUS improves the detection of HCC in patients with HCV-induced liver cirrhosis. Also, CEUS makes it possible to rule out malignancy in many cases where baseline US shows indeterminate focal lesions. In low-endemic countries, the use of CEUS in screening for HCC may be considered.     

Ultrasound-guided core needle biopsy of non-palpable breast lesions: a prospective analysis in 204 cases

Purpose: To assess the diagnostic value of ultrasound (US)-guided 14 G core needle breast biopsy in non-palpable suspicious breast lesions.

Material and Methods: From August 1997 to April 2001, 198 patients with 204 suspicious non-palpable breast lesions underwent US-guided large core needle biopsy. Biopsies were performed with a free-hand technique using US equipment with a 7.5 MHz linear-array transducer; a minimum of three cores were obtained from each lesion. Pathological findings in US-guided core biopsy were correlated to findings in subsequent surgery or long-term (more than 2 years) imaging follow-up.

Results: Among the 204 non-palpable breast lesions for which histopathological findings were obtained by US-guided core biopsy, 118 were malignant (114 carcinoma, 2 metastasis, 1 lymphoma, and 1 malignant phyllodes tumor) and 86 were benign (4 carcinoma and 82 benign lesions confirmed at surgery or after at least 2 years of follow-up). Sensitivity, specificity, positive predictive value, and negative predictive value for diagnosis of malignancy in our series were 97%, 100%, 100%, and 95%, respectively. Diagnostic yield with 1, 2, 3, and 4 specimens per lesion was 73.5%, 88%, 94%, and 97.5%, respectively.

Conclusion: US-guided core needle biopsy is a sensitive percutaneous biopsy method for diagnosing non-palpable breast lesions. To achieve a high diagnostic yield, a minimum number of three cores per lesion is advisable.     

MR Arthrography of the Hip

Magnetic resonance imaging (MRI) of the hip has been valuable in the diagnosis of occult osseous abnormalities and of periarticular soft tissue disorders. MRI has been less useful in the evaluation of acetabular labral tears and other intra-articular abnormalities. Image optimization is more technically challenging in the hip than in smaller joints because the overlying soft tissues are thicker, resulting in decreased spatial and contrast resolutions that may not be adequate to distinguish the acetabular labrum from subchondral bone, articular cartilage, and joint capsule. MR arthrography (MRA) extends the capabilities of conventional MRI because contrast solution separates intra-articular structures and outlines abnormalities. In hips with suspected acetabular labral injury, arthrographic MR images demonstrate the location and length of tears and the presence of associated capsular defects. Arthrographic MR images may also enable the accurate diagnosis of cartilage lesions and intra-articular loose bodies. This article illustrates normal arthrographic MR features of the hip as well as pathologic disorders of the acetabular labrum, capsule, and articular cartilage     

Evaluation of radial-sequence imaging in detecting acetabular labral tears at hip MR arthrography

Objective In recent years, radial imaging has been advocated for improved visualization of the acetabular labrum in magnetic resonance arthrography of the hip. The purpose of this study was to investigate whether radial imaging demonstrates labral tears not visible on standard imaging planes. Methods Fifty-four consecutive magnetic resonance (MR) arthrograms of the hip that included radial imaging over 2 years were retrospectively analyzed by two radiologists. Standard imaging planes and radial imaging were reviewed for identification of labral tears in four specific areas of the labrum: anterosuperior, posterosuperior, anteroinferior, and posteroinferior. The standard imaging sequences include fat-saturated spin-echo T1-weighted images in the coronal and oblique axial planes, non-fat-saturated T1-weighted images in the coronal and sagittal planes, and T2-weighted sequence in the axial plane. Radial imaging was performed as previously described using fat-saturated T1-weighted sequences. Results Using standard imaging planes, 50 anterosuperior, 31 posterosuperior, 10 anteroinferior, and 9 posteroinferior labral tears were detected in 54 MR arthrograms of the hip. Using radial sequences alone, 44 anterosuperior, 25 posterosuperior, 9 anteroinferior, and 5 posteroinferior labral tears were detected. In all four areas of the labrum, the radial imaging did not show any labral tear not seen on standard imaging planes. Discussion In MR arthrography of the hip, radial imaging did not reveal any additional labral tears. Standard imaging planes sufficiently demonstrate all acetabular labral tears.     

Pulmonary perfusion in acute pulmonary embolism: agreement of MRI and SPECT for lobar, segmental and subsegmental perfusion defects

Purpose: To assess prospectively the agreement of magnetic resonance (MR) pulmonary perfusion with single-photon emission computed tomography (SPECT) perfusion for perfusion defects down to the subsegmental level in patients with suspected pulmonary embolism (PE).

Material and Methods: In 41 patients with suspected PE, contrast-enhanced MR pulmonary perfusion (3D-FLASH, TR/TE 1.6/0.6 ms) was compared to SPECT perfusion on a per-examination basis as well as at the lobar, segmental, and subsegmental level.

Results: The MRI protocol was completed in all patients, and mean examination time was 3 min 56 s. MR perfusion showed a very high agreement with SPECT (kappa value per examination 0.98, and 0.98, 0.83, and 0.69 for lobar, segmental, and subsegmental perfusion defects, respectively). Of 15 patients with PE, MR perfusion detected 14 cases.

Conclusion: The very high agreement of MR perfusion with SPECT perfusion enables the detection of subtle findings in suspected PE.     

Ultrasound and power Doppler evaluation of the hand and wrist in patients with psoriatic arthritis

Purpose: To evaluate the ability of high-resolution and power Doppler sonography in detecting joint and tendon abnormalities in patients with psoriatic arthritis (PsA) of the hands and wrists compared with clinical and radiological findings.

Material and Methods: Thirty-six patients with psoriatic arthritis of the hands and wrists and 10 healthy controls were examined with ultrasound (US). The degree of synovial proliferation, tenosynovitis, presence of joint effusion as well as the vascularity of synovial tissue was estimated. US findings were scored using a newly devised scoring system.

Results: Thirty-two patients had articular synovial proliferation and/or tenosynovitis/tendinitis or joint effusion in one or more joints according to US. Twenty-two patients had tendon changes; only five had joint effusion. The synovial, Doppler, and total articular-teno scores were all significantly correlated to the number of swollen joints. The scores, however, did not correlate to other clinical or laboratory measurements of disease activity.

Conclusion: US proved effective in demonstrating PsA involvement of the hands and wrists and was more sensitive than clinical examination in detecting pathology. Long-term follow-up studies are needed to evaluate whether this can change the traditional approach for assessing involvement of joints and tendons in PsA.     

Sublabral sulcus at the posteroinferior acetabulum: a potential pitfall in MR arthrography diagnosis of acetabular labral tears

OBJECTIVE: Our study correlated findings on hip MRI and MR arthrography with hip arthroscopy to assess the location, prevalence, and potential pitfall of a normal acetabular sublabral sulcus. MATERIALS AND METHODS: We retrospectively collected 58 hip MRI studies along with surgical reports in 58 patients who underwent hip arthroscopy over a 5-year period. Intraoperative photography (n = 23), radiography (n = 56), unenhanced MRI (n = 13), and MR arthrography (n = 54) studies were available for review. Two radiologists described hip anatomy on radiology studies with agreement by consensus. RESULTS: A normal posteroinferior sublabral groove was confirmed on available arthroscopy photographs in four (17.4%) of 23 hips. In each of these four patients, the anatomic sublabral groove correlated with apparent partial labral detachment on MR arthrography. On review of all studies, 13 hips (22.4%) without a posterior labral tear at surgery had imaging findings of a sublabral sulcus. The sulcus was not associated with acetabular dysplasia, which was radiographically noted in 12 cases (21.4%). Preoperatively, the sulcus was misdiagnosed as a tear in two cases. Labral tears were anterior or anterosuperior in 51 patients. CONCLUSION: A posteroinferior sublabral groove is a relatively common normal anatomic hip variation. If not recognized as normal, the sulcus may serve as a diagnostic pitfall on MR arthrography. Its location is distinct from most labral tears. We did not discover a sublabral sulcus at the anterior or anterosuperior acetabulum, the most common sites of labral injury.     

Ultrasound guidance for puncture and injection in the radiocarpal joint

Background: The use of intra-articular contrast agent has been shown to increase the diagnostic accuracy of wrist magnetic resonance (MR) in patients with suspected trauma of the wrist ligaments. Traditionally, the contrast agent has been applied under fluoroscopic guidance.

Purpose: To present a method based on ultrasound guidance for the injection of intra-articular contrast agent in wrist MR.

Material and Methods: One hundred eight patients (56 female and 52 male, mean age 36 years) referred for wrist MR arthrograms due to suspected ligament rupture were included in this retrospective study. The preferred injection point is about 1 cm distal to Lister's tubercle in the distal radius. A correct positioning of the injection needle can be ensured using ultrasound guidance.

Results: Using this technique, the injection was intra-articular in 93.5% of the 108 injections over a 2-year learning period.

Conclusion: Ultrasound guidance of the contrast injection in radiocarpal MR arthrograms is a cost-effective and safe alternative to fluoroscopically guided procedures. Furthermore, the use of ultrasound guidance provides clues about possible fluid collections within the joint.     

MR arthrography of the hip: normal intra-articular structures and common disorders

This pictorial review illustrates the anatomical features of normal intra-articular components of the hip and their common disorders on MR arthrography. On T1-weighted MR arthrograms, the normal contrast-filled joint cavity shows a homogeneous high signal intensity. Normal acetabular labrum appears as a well-delineated triangle showing a low signal intensity, surrounded by contrast material in the perilabral recess. Intra-articular paramagnetic contrast outlines labral tears, loose bodies, communicating labral cysts and cartilage lesions (traumatic tears, focal defects, degenerative fissures and thinning), and improves their detection. Overall, MR arthrography enables accurate detection and staging of hip intra-articular structure abnormalities. Received: 6 June 1998; Revision received: 2 January 1999; Accepted: 2 April 1999