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Biomedical subjects

C A Helms

Publications and source records attributed to C A Helms.

At least 37 records · Page 2Linked to original sources
PubMed1999

The MR imaging features of the posterior intermalleolar ligament in patients with posterior impingement syndrome of the ankle.

OBJECTIVE: To describe the MR imaging features of the posterior intermalleolar ligament (IML) in patients with posterior impingement syndrome (PIS) of the ankle. DESIGN AND PATIENTS: Three patients (one male and two females, 13-25 years of age) are presented. Each patient presented clinically with symptoms of PIS of the ankle. Plain film examination was negative for a structural cause of the PIS in all patients. MR images were obtained with a 1.5 T scanner using an extremity coil. Clinical data and, in one patient, findings at ankle arthroscopy, were correlated with the results of MR imaging. RESULTS: Ankle MR images from the three patients with a clinical diagnosis of PIS are presented. Findings in all patients included: (1) absence of another structural cause of the PIS (i.e., an os trigonum, trigonal process, fracture, loose bodies, etc.), (2) identification of the IML as a structure discrete from the posterior talofibular and tibiofibular ligaments, and (3) prominence of the IML as indicated by (a) identification of the IML in three different imaging planes, and (b) a caliber of the IML comparable to that of the conventional posterior ankle ligaments visualized in the same imaging plane. Arthroscopic resection of a meniscoid IML resulted in resolution of the PIS in one of the patients presented. CONCLUSIONS: MR imaging is an effective means of investigating the IML as a potential cause of PIS. The identification of a prominent IML in the absence of another structural cause of PIS indicates that impingement of the IML is the most likely cause of PIS.

Adolescent↗
PubMed1999

Chronic avulsive injury of the deltoid insertion in adolescents: imaging findings in three cases.

The clinical and imaging (magnetic resonance [MR] imaging, radiography, and bone scintigraphy) findings in three adolescent boys with chronic avulsive injury at the deltoid insertion are presented. MR imaging enabled the exclusion of findings suggestive of malignancy and the localization of abnormalities to the deltoid insertion site. Findings included cortical thickening and irregularity of the deltoid tubercle, with or without adjacent soft-tissue edema.

Adolescent↗
PubMed1999

The MR appearance of the infrapatellar plica.

OBJECTIVE: Our purpose is to describe the MR appearance and clinical relevance of the infrapatellar plica of the knee and to assess possible imaging pitfalls resulting from lack of recognition of this normal structure. Seven patients--four from our institution and three from our teaching file from outside institutions--were selected because they displayed the imaging features of the infrapatellar plica. CONCLUSION: The infrapatellar plica is readily appreciated on sagittal MR images of the knee as a low-signal-intensity structure in the intercondylar notch just anterior to the anterior cruciate ligament (ACL). The infrapatellar plica is important to recognize for the following reasons: It may be confused with an intact ACL because of its proximity and similar signal characteristics; it may pose difficulty to the arthroscopist when attempting to move instruments from the medial to lateral compartments of the knee; it can block clear visualization of the ACL during arthroscopy; and it can impair retrieval of loose bodies in the intercondylar notch. Familiarity with the infrapatellar plica should allow one to differentiate this normal structure from other structures in the knee and aid in preoperative planning.

Adult↗
PubMed1999

MR imaging of fibrocartilaginous masses arising on the margins of spondylolysis defects.

OBJECTIVE: Spondylolysis is reported in up to 7% of the population. An uncommon process that can accompany a pars interarticularis defect is a fibrocartilaginous mass, which can cause impression on the nerve roots and thecal sac. Recognition is important so that the presence may be addressed at the time of surgery. This report describes the MR imaging appearance and clinical significance of a fibrocartilaginous mass in association with spondylolysis. MATERIALS AND METHODS: We reviewed data regarding 336 patients who had lumbar spine imaging at our institution during a 12-month period. Contiguous axial and sagittal MR imaging using T1-weighted and fast spin-echo T2-weighted sequences was used. Images were evaluated for a mass of tissue surrounding the pars defect with MR characteristics of cartilaginous and fibrous low signal intensity on T1-weighted images and low to intermediate signal intensity on T2-weighted images. The position of the fibrocartilaginous mass and its relation to the thecal sac were noted. Surgical correlation between those patients with a fibrocartilaginous mass and those without was examined. RESULTS: Twenty-nine (8.6%) of 336 patients were identified as having a pars interarticularis defect. A fibrocartilaginous mass was present in 26 (90%) of 29 patients. Six (21%) of the 29 patients had a mass effect on the thecal sac. Of the remaining 23 patients, 20 had a fibrocartilaginous mass external to the thecal sac, and three did not show any fibrocartilaginous mass. Histologic analysis in one patient confirmed the fibrous and cartilaginous nature of the lesion at the pars defect. CONCLUSION: A fibrocartilaginous mass was present in 90% of the patients with spondylolysis. Mass effect on the thecal sac that required surgery was identified in 21% of the patients with spondylolysis. Awareness of this mass and proper imaging protocols will enable the radiologist to preoperatively alert the surgeon to its presence.

Adult↗
PubMed1998

Acute brachial neuritis (Parsonage-Turner syndrome): MR imaging appearance--report of three cases.

Magnetic resonance (MR) imaging findings in three patients with acute onset of neuritic shoulder pain and weakness included high signal intensity in supra- and infraspinatus muscles (n = 2), partial involvement of infraspinatus muscle (n = 1) and of deltoid muscle (n = 1), and atrophy of supra- and infraspinatus muscles (n = 2). Clinical diagnosis of acute brachial neuritis (Parsonage-Turner syndrome) correlated with MR imaging results in all cases.

Acute Disease↗
PubMed1998

Hypertrophied palmaris longus muscle, a pseudomass of the forearm: MR appearance--case report and review of the literature.

Magnetic resonance (MR) imaging of the forearm was performed to evaluate a presumed forearm soft-tissue tumor in a 26-year-old man. Sagittal and axial images revealed a mass isointense to muscle just medial to the flexor carpi radialis tendon (in the expected location of the palmaris longus muscle). A diagnosis of hypertrophied palmaris longus muscle was made. The radiologist must be familiar with the MR imaging appearance of normal variants of the palmaris longus muscle, as this can obviate surgery.

Adult↗
PubMed1998

The absent bow tie sign in bucket-handle tears of the menisci in the knee.

OBJECTIVE: Bucket-handle tears of the menisci are one of the most frequently missed diagnoses in MR examinations of the knee. This article describes the "absent bow tie sign," which can be used to identify bucket-handle tears on routine MR examinations of the knee. MATERIALS AND METHODS: The arthroscopic surgical reports (n = 350) from a single orthopedic surgeon's practice during a 24-month period were examined for patients who had a diagnosis of bucket-handle tear and who underwent MR imaging before surgery (n = 32). The MR examinations were retrospectively evaluated for the presence of a bow tie sign. The bow tie sign was considered normal when two sagittal images showed the body segment (a bow tie appearance). The bow tie sign was considered abnormal, consistent with a bucket-handle tear, when only one or no body segment was seen (the absent bow tie sign). Coronal images were evaluated for a truncated meniscus. Also, each MR examination was scrutinized for a displaced fragment and a double posterior cruciate ligament (PCL) sign. RESULTS: Thirty-three bucket-handle tears were found at arthroscopy in 32 patients. One patient had tears of the medial and lateral menisci. The absent bow tie sign was seen in 32 of the 33 cases (sensitivity, 97%) and correlated with the medial or lateral meniscus that was reported torn at arthroscopy. The single false-negative result occurred in a patient with a nondisplaced bucket-handle tear. The findings in 31 contralateral normal menisci were all negative for an absent bow tie sign (specificity, 100%). A displaced fragment was found in 30 (94%) of 32 cases. The coronal images showed a truncated meniscus in 21 (64%) of 33 cases. A double PCL sign was seen in 10 (30%) of 33 cases. CONCLUSION: The absent bow tie sign is an easily applied finding that can be used with good sensitivity to diagnose bucket-handle tears of the menisci on MR imaging. This sign has a higher accuracy rate than other findings common with bucket-handle tears, such as displaced fragments, a truncated appearance of the meniscus on coronal images, and the double PCL sign.

Adult↗
PubMed1997

MR imaging of supra-acetabular insufficiency fractures.

OBJECTIVE: Diagnosis of insufficiency fractures in the pelvis is difficult, especially in patients with prior malignancy, irradiation, steroid therapy or osteoporosis. This report shows the MR imaging appearance of supra-acetabular insufficiency fractures and how they can be differentiated from metastatic disease. DESIGN AND PATIENTS: Twelve patients (four men, eight women, average age 72.8 years) at risk for pelvic insufficiency fractures and who had pelvic or hip pain were studied with MR imaging. Indications were possible recurrent tumor or previous radiation to the pelvis (7 patients); osteoporosis from steroid use in rheumatoid arthritis (two patients); to exclude osteonecrosis of the hip (two patients); or to rule out a hip fracture (one patient). RESULTS: A characteristic linear region of low signal intensity on both T1- and T2-weighted sequences was found in the supra-acetabular region paralleling the superior acetabulum in a curvilinear are in 92% (11/12) of cases, and oblique in origin in 8% (1/11). Diffuse bands of high signal on T2-weighted images indicated surrounding edema. In two cases, MR findings obviated biopsy. One patient underwent a biopsy prior to the imaging studies being reviewed. All patients were treated conservatively and did well. DISCUSSION: Attention to insufficiency fractures has previously focused on characteristic locations in the sacrum and pubic bones. Supra-acetabular insufficiency fractures also occur and are difficult to diagnose without a high degree of suspicion. MR imaging is a useful tool for diagnosing supra-acetabular insufficiency fractures. The characteristic MR imaging appearance of these fractures can preclude additional diagnostic studies and therapy in most instances.

Acetabulum↗
PubMed1997

Pelvic stress injuries: the relationship between osteitis pubis (symphysis pubis stress injury) and sacroiliac abnormalities in athletes.

OBJECTIVE: To demonstrate with radiographic imaging the association between pubic stress injury and sacroiliac abnormalities in athletes. DESIGN AND PATIENTS: Eleven athletes (9 men and 2 women), comprising seven male long-distance runners, one male soccer player, one male and two female basketball players, were imaged with plain films for complaints of pubic symphysis pain, sciatica, groin pain, or a combination of these complaints. In addition to the plain films, four patients were imaged with CT, two patients had MR imaging, and a bone scan was performed in three patients. Anteroposterior plain films of the pelvis of 20 patients without back pain or pubic pain were evaluated for comparison as a control group (ages 18-72 years, average 49 years; 11 women and 9 men). RESULTS: All athletes showed plain film evidence of either sclerosis, erosions or offset at the pubic symphysis. Four had avulsion of cortical bone at the site of insertion of the gracilis tendon. Four patients demonstrated sacroiliac joint abnormalities on plain films consisting of sclerosis, erosions and osteophytes, and in one of these athletes, bilateral sacroiliac changes are present. Two patients with normal sacroiliac joints on plain films had a bone scan showing increased radionuclide uptake bilaterally at the sacroiliac joints. One patient with both plain film and CT evidence of sacroiliac abnormalities had an MR examination showing abnormal signal at both sacroiliac joints and at the pubic symphysis. A sacral stress fracture was found on CT in one patient with complaints of sciatica. In the control group, six patients, all over the age of 55 years, had mild sclerosis of the symphysis, but no plain film evidence of sacroiliac abnormalities. CONCLUSION: We have found a group of athletes in whom stress injuries to the pubic symphysis are associated with changes in the sacroiliac joint as demonstrated by degenerative changes or in the sacrum as manifested as a sacral stress fracture. These findings are probably due to abnormal stresses across the pelvic ring structure that lead to a second abnormality in the pelvic ring. The abnormality in the sacrum is not always well seen with conventional imaging. Recognition of the association of stress injury of the symphysis with back pain is important in that it can help avoid inappropriate studies and diagnostic confusion.

Adolescent↗
PubMed1997

Osteonecrosis after contact neodymium:yttrium aluminum garnet arthroscopic laser meniscectomy.

OBJECTIVE: The purpose of this report is to describe two cases of osteonecrosis that occurred after arthroscopic meniscectomy with a contact neodymium:yttrium aluminum garnet laser system. The patients developed increasing knee pain and disability 5 months and 6 months after laser meniscectomy. MR imaging showed subchondral osteonecrosis in the femoral condyle and tibial plateau immediately adjacent to the site of laser meniscectomy in both patients. One patient required a total knee replacement to alleviate knee symptoms, and the other patient required a tibial osteotomy and surgical elevation of collapsed tibial articular surface. CONCLUSION: To our knowledge, this complication of laser arthroscopic meniscectomy has not been reported in the radiology literature. The clinical and MR imaging features of this important complication are described and possible causative mechanisms are discussed.

Adult↗
PubMed1996

Absence or interruption of the supra-acetabular line: a subtle plain film indicator of hip pathology.

OBJECTIVE: To show that absence or interruption of the supra-acetabular line is a subtle plain film indicator of pathology in the acetabulum. DESIGN: Nineteen hips from 17 patients with known disease processes involving the acetabulum as demonstrated by subsequent magnetic resonance imaging, bone scan or plain film follow-up were evaluated with antero-posterior (AP) plain films of the pelvis. Three additional cases were diagnosed prospectively using interruption of the supra-acetabular line as the criterion for inclusion. Fifty AP plain films of the pelvis in patients without hip pain were examined prospectively to determine normal imaging criteria. RESULTS AND CONCLUSIONS: The normal supra-acetabular line measures 2-3 mm in thickness superiorly and is a thin sclerotic line in the medial aspect. In all 22 hips (with pathology) in this series, the line was interrupted or absent. Loss or interruption of the supra-acetabular line may thus be a subtle pain film indicator of a disease process involving the acetabulum. This plain film sign has not previously been reported.

Acetabulum↗
PubMed1996

Semimembranosus-tibial collateral ligament bursitis: MR imaging findings.

PURPOSE: The purpose of this paper is to describe the MR imaging characteristics of semimembranosus-tibial collateral ligament (SMTCL) bursitis. MATERIALS AND METHODS: Fifteen patients (37-68 years old) with medial joint pain and presumed internal derangements of the knee underwent MR imaging. Fluid collections around the SMTCL were found prospectively in five patients. Our retrospective evaluation of recent MR imaging cases that had been previously diagnosed as pes anserinus bursitis revealed 10 additional cases with similar findings. RESULTS: We believe that SMTCL bursitis clinically explained the patients' medial pain in all cases diagnosed prospectively. We gave the additional cases the same diagnosis presumptively. CONCLUSIONS: SMTCL bursitis has a characteristic MR imaging appearance of fluid draped over the semimembranosus tendon in the shape of an inverted U. This entity can clinically mimic internal derangement of the knee, typically causing pain more superior and posterior to that of pes anserinus bursitis. MR imaging is useful in diagnosing SMTCL bursitis and avoiding unnecessary knee arthroscopy.

Adult↗
PubMed1995

Acute pes anserine bursitis: MR imaging.

PURPOSE: To determine the magnetic resonance (MR) imaging appearance of acute pes anserine bursitis. MATERIALS AND METHODS: Four patients (aged 40-50 years) with presumed internal derangements of the knee underwent MR imaging; at that time, collections of fluid were found in the pes anserine bursa, but no other abnormalities were noted. RESULTS: Pes anserine bursitis was clinically diagnosed in all four patients when MR findings and physical examination findings were correlated. CONCLUSION: Pes anserine bursitis has a characteristic MR appearance of fluid beneath the tendons of the pes anserinus at the medical aspect of the tibia near the joint line. Pes anserine bursitis can clinically mimic an internal derangement of the knee, which can result in the performance of unnecessary arthroscopy. MR imaging can be useful in diagnosing pes anserine bursitis and obviating surgery.

Acute Disease↗
PubMed1995

Plantaris muscle injury: evaluation with MR imaging.

PURPOSE: To determine the MR imaging appearance of injury to the plantaris muscle. MATERIALS AND METHODS: Fifteen patients with sports-related injuries to the lower leg underwent magnetic resonance (MR) imaging with T1- and T2-weighted, gradient-echo T2*-weighted, short inversion time inversion-recovery, and fast spin-echo sequences. The plantaris muscle and tendon, as well as the surrounding structures, were retrospectively examined for abnormalities. RESULTS: All 15 patients had rupture of the plantaris muscle or strain. An associated torn anterior cruciate ligament (ACL) was found in 10 of 15 patients. Five injuries were isolated or associated with partial tears of the gastrocnemius or popliteus muscle. At initial presentation, three patients had large, focal elongated fluid collections between the medial head of the gastrocnemius muscle and the soleus muscle. CONCLUSION: Rupture of the plantaris muscle may occur at the myotendinous junction with or without an associated hematoma or partial tear of the medial head of the gastrocnemius muscle. A strain of the more proximal plantaris muscle may also occur as an isolated injury or in conjunction with injury to the ACL.

Adult↗