"Popeye muscle" morphology in OBPI elbow flexion contracture

BACKGROUND

The pathophysiology of elbow flexion contracture (EFC) in obstetrical brachial plexus injury (OBPI) is not established. In basic science models, neonatal denervation leads to impaired muscle growth. In clinical studies, diminished growth is correlated with extent of denervation, and improved with surgical repair. In EFC, the biceps are clinically short and round vs the contralateral size, termed the "Popeye muscle". The objective of this study was to determine if the biceps morphology (muscle belly and tendon length) in arms with EFC secondary to OBPI is different vs the contralateral.

METHODS

This is a retrospective matched-cohort study. Patients with unilateral EFC (>20°) secondary to OBPI were identified (median = 6.6 years, range = 4.7-16.8). A blinded radiologist used computed tomography to measure length of the biceps short head muscle belly, and tendon bilaterally using standardised anatomical landmarks.

RESULTS

Twelve patients were analyzed. The biceps muscle belly in the injured arm was shorter in all patients vs contralateral, mean difference = 3.6 cm (80%), p < 0.001. The biceps tendon in the injured arm was longer in all patients vs contralateral, mean difference = 1.13 cm (127%), p < 0.001. The total biceps length in the injured arm was shorter in all patients vs contralateral, mean difference = 2.5 cm (89%), p < 0.001.

CONCLUSIONS

This is the first human study confirming growth discrepancy of an elbow flexor in EFC. Distinct biceps morphology is demonstrated, with a significantly shorter muscle belly and overall length, but longer tendon vs normal. This is termed the "Popeye muscle" for its irregular morphology. Findings are consistent with impaired limb growth in denervation.

The association between avulsions of the reflected head of the rectus femoris and labral tears: a retrospective study

BACKGROUND

The aim of this study was to investigate if an association existed between the reflected head of rectus femoris avulsion injuries and labral tears in pediatric patients referred for magnetic resonance arthrography (MRA) or magnetic resonance imaging (MRI) evaluation.

METHODS

Electronic medical records of the patients between the ages of 12 and 18 who were treated at the hospitals affiliated by McMaster University between June 2000 and November 2010 with a diagnosis of rectus femoris avulsion injuries were retrospectively identified and analyzed. Patients were included if they had magnetic resonance imaging or MRA images of their hip.

RESULTS

Nine patients with avulsion injuries of the rectus femoris muscle were identified. The patient population consisted of 4 females and 5 males (range, 8 to 17 y, mean age 14 y). All injuries occurred during sports activity, which included running and kicking during soccer, skating in hockey, and a squatting exercise. MRA examination of 7 of these patients demonstrated associated labral tears. All patients were initially treated conservatively. Five patients continued to sustain from residual pain in the 9 months after the initial injury. Two of these patients with significant refractory pain were subsequently treated with hip arthroscopy. Intraoperatively, 1 small labral tear and 1 labral avulsion were identified and treated.

CONCLUSIONS

This study suggests that there may be an association between avulsion of the reflected head of rectus femoris and labral injuries and that there may be an underlying spectrum of traction injuries. Patients with rectus femoris avulsion injuries with persistent symptoms may be at risk for concurrent traumatic labral tears.

LEVEL OF EVIDENCE

Level 4, retrospective case series.

How to measure scapholunate and Cobb's angles on MRI and CT

The measurement of angles between anatomical structures is common in radiological and orthopedic practice. Frequently used measurements include scapholunate angle for assessment of wrist instability and Cobb's angle used for assessment of scoliosis. Measurements of these angles are easily performed on plain X-ray radiographs. However, the situation is more complicated when these measurements are to be performed on cross-sectional (CT or MRI) examinations. On some of the diagnostic workstations, it is not possible to perform angle measurements between the structures if they are not identified on the same image and are located on different images of the same projection or plane. We present a simple solution to measure angles between structures on different images that can be used both in CT and MR.

Linguistic history of posterior reversible encephalopathy syndrome: mirror of developing knowledge

BACKGROUND

the term posterior reversible encephalopathy syndrome (PRES) was first proposed in 2000. Since then, the acronym PRES has become very popular in imaging and clinical literature as it is short, easy to say and remember, and neatly couples the frequent localization of neuroimaging findings along with the typical outcome of this syndrome. Another possible reason for the popularity of this acronym in clinical circles is the connotation of PRES with (elevated blood) PRESsure, as a majority of cases are believed to be associated with hypertension. However, problems exist with the interpretation and common understanding of PRES, questioning the appropriateness of "P" and "R" in the acronym. The linguistic issues related to the acronym of PRES are interesting.

OBJECTIVES

the aim of this work is to analyze the controversies related to the acronym of PRES.

RESULTS

in 2006, modifying the meaning of the acronym was suggested, renaming it Potentially Reversible Encephalopathy Syndrome in order to adjust to the cases when posterior involvement is not prominent and emphasize that the reversibility is not spontaneous. This meant the creation of a backronym, where the new phrase is constructed by starting with an existing acronym.

CONCLUSION

this new backronym indicates that the original acronym of PRES has become a misnomer.

Laparoscopic excision of infarcted accessory spleen

An accessory spleen is present in about 10-30% of the population and, usually, does not cause symptoms. We present a case report of an unusual presentation of accessory spleen infarction, with a literature review. A 12-year old male presented with acute left-upper quadrant pain that slowly resolved. An ultrasound and computed tomography scan showed a 3.5 x 2.5 x 2 cm solid mass abutting and displacing the splenic flexure of the colon, with surrounding inflammatory changes. This was interpreted as a colonic duplication cyst, and the boy was treated with antibiotics and underwent elective laparoscopic exploration. It was removed laparoscopically without complication and, on pathologic examination, proved to be consistent with an infarcted accessory spleen. Less than two dozen similar cases of accessory spleen infarction have been reported in the literature, most presenting with acute abdominal pain. Preoperative diagnoses included appendicitis, ovarian torsion, neoplasm, and, in our case, colonic duplication. The natural course of infarcted accessory spleen would be to atrophy, but, even with advanced imaging techniques, it may be impossible to diagnose infarcted accessory spleen with enough confidence to avoid surgery.

Displacement of the temporomandibular joint disk: correlation between clinical findings and MRI characteristics

BACKGROUND AND OBJECTIVE

Disk displacement frequently causes dysfunction of the temporomandibular joint (TMJ). Magnetic resonance imaging (MRI) of the TMJ is 95% accurate in the assessment of disk position and form. Various restorative procedures are used for treatment of disk displacement. However, several authors have noted a lack of correlation between MRI findings of disk displacement and the extent of pain and dysfunction of the TMJ. The purpose of this study was to evaluate whether MRI findings of various degrees of disk displacement could be correlated with the presence of clinical signs and symptoms in patients with a clinical disorder of the TMJ.

MATERIALS AND METHODS

One hundred and forty-four TMJs (in 72 patients) were imaged. Displacement of the posterior band in relation to the condyle was quantified as mild or significant.

RESULTS

Disk displacement was found in 45 (54%) of the 84 symptomatic joints and 13 (22%) of the 60 asymptomatic joints. Among the 84 symptomatic joints, 31 (37%) had disk displacement with reduction and 14 (17%) had disk displacement without reduction. In the latter group, 11 (79%) of the 14 joints had significant displacement of the posterior band (8 or 9 o'clock) and 21% had mild displacement of the posterior band (10 o'clock). Of the 60 clinically asymptomatic joints, 47 (78%) had no signs of disk displacement on MRI, whereas 13 (22%) had disk displacement with reduction. None of the asymptomatic joints had disk displacement without reduction. The difference in occurrence of disk displacement between symptomatic and asymptomatic joints was statistically significant (54% vs. 22%; p < 0.001). However, the difference in occurrence of disk displacement with reduction of the disk on mouth opening was not statistically significant (37% vs. 22%; p = 0.06).

CONCLUSIONS

Disk displacement on MRI correlated well with clinical symptoms in cases of significant disk displacement and in cases of disk displacement without reduction. When disk displacement with reduction was mild, there was no statistically significant difference between symptomatic and asymptomatic joints, which suggests that other causes should be considered.

MR arthrography of the wrist: controversies and concepts

Magnetic resonance arthrography (MRA) has become the preferred modality for imaging patients with internal derangement of the wrist. However, several aspects of MRA use need to be clarified before a standardized approach to the imaging of internal derangement of the wrist can be developed. The objective of the study is to evaluate the efficiency of different magnetic resonance (MR) sequences in the detection of lesions of the triangular fibrocartilage complex (TFCC) and scapholunate and lunotriquetral ligaments on direct MRA. Thirty-one consecutive direct magnetic resonance arthrographic examinations of the wrist using a wrist surface coil were performed for the assessment of the TFCC and intrinsic ligaments on a 1.5-T MR imaging system (Signa; 16 channel, Excite, GE Healthcare, Milwaukee, WI, USA). All patients had wrist pain, and in six cases, there was associated clinical carpal instability. The presence, location, and extent of TFCC, scapholunate ligament (SLL), and lunotriquetral ligament (LTL) lesions on T1 fat-saturated, multiplanar gradient recalled (MPGR) and short tau inversion recovery (STIR) images were identified, compared, and analyzed. Forty-one lesions of the TFCC, SLL, and LTL were visualized on contrast-sensitive (T1 fat-saturated) images in 23/31 (74.2%) patients. Twenty-one lesions of the TFCC and intrinsic ligaments were visualized on noncontrast-sensitive (MPGR and STIR) images (15 tears of the TFCC and six tears of the SLL and LTL). All of these lesions were seen on T1 fat-saturated images; 48.8% (20/41) lesions seen on T1 fat-saturated images (eight tears of TFCC and 12 tears of SLL and LTT) were not seen on MPGR and/or STIR images. Superior contrast resolution, joint distention, and the flow of contrast facilitate the diagnosis of lesions of the TFCC and intrinsic ligaments on contrast-sensitive sequences making MRA the preferred modality for imaging internal derangements of the wrist. Little agreement exists regarding the value and location of perforations of the intrinsic ligaments given that both traumatic and degenerative perforations may be symptomatic. Noncommunicating defects of the ulnar attachments of the triangular fibrocartilage (TFC), tears of the dorsal segment of the SLL, and defects at the lunate attachment of the SLL have a higher likelihood of being symptomatic and caused by trauma rather than by degenerative perforation. Although no consensus exists, it would appear that most arthrographies should be started with a radiocarpal injection. Injection into the distal radioulnar joint should be added if no communicational defects are visualized following radiocarpal injection in patients with ulnar-sided wrist pain.

Hurthle cell neoplasms of the thyroid: sonographic appearance and histologic characteristics

OBJECTIVE

The purpose of this study was to determine the sonographic features of Hürthle cell neoplasms (HCNs) of the thyroid.

METHODS

We retrospectively analyzed the sonographic appearance of 15 histologically proven HCNs in 15 patients aged 16 to 70 years (mean age, 44 years). Sonographic features that were reviewed included the size and echogenicity of the tumors, the presence of cystic areas or calcifications, and detectable blood flow on color Doppler imaging. Correlation of sonographic findings with pathologic results was performed.

RESULTS

The tumors ranged from 0.4 to 7 cm in diameter, but most were less than 3 cm in diameter. Four (27%) of the 15 tumors were homogeneously hypoechoic. Two tumors (13%) were predominantly hypoechoic with isoechoic areas to thyroid parenchyma. Two (13%) neoplasms were isoechoic to thyroid parenchyma. Four (27%) tumors were predominantly isoechoic, containing hypoechoic areas, and 3 (20%) tumors were hyperechoic. Three neoplasms contained cystic components. None of the tumors contained calcifications. One tumor was avascular on Doppler examination. One neoplasm showed only peripheral blood flow. Thirteen tumors showed internal vascularity, 7 of them with peripheral blood flow. Twelve HCNs were benign, and 3 were malignant on pathologic examination.

CONCLUSIONS

Hürthle cell neoplasms show a spectrum of sonographic appearances from predominantly hypoechoic to hyperechoic lesions and from peripheral blood flow with no internal flow to extensively vascularized lesions. Pathologic criteria differentiating benign and malignant HCNs (absence or presence of a capsular breach, vascular or extrathyroidal tissue invasion, nodal involvement, and distant metastasis) are beyond the resolution of sonography and fine-needle aspiration biopsy and require removal of the entire lesion. This precludes diagnosis and characterization of HCNs by sonography.

CT findings of normal and inflamed appendix in groin hernia

Acute appendicitis with the vermiform appendix located in a groin hernia is a rare condition. The preoperative diagnosis is important to decrease morbidity. We describe the computed tomography imaging characteristics of three cases of normal and inflamed appendices in inguinal and femoral hernias. We provide a review of the literature and consider the implications for surgical management.

Economic and ethical impact of extrarenal findings on potential living kidney donor assessment with computed tomography angiography

To determine the prevalence and spectrum of extrarenal findings in a screening population of potential living kidney donors undergoing renal Computed tomography angiography (CTA) and evaluate their impact on subsequent patient management and imaging costs. Two radiologists retrospectively reviewed 175 consecutive renal CTA's performed for assessment of potential living kidney donors. Extrarenal radiological findings were recorded and classified according to high, medium, or low importance based on clinical relevance and the need for further investigations and/or treatment. The cost of additional imaging examinations was calculated using 2002 Canadian (British Columbia) reimbursements. There were 73 extrarenal findings in 71/175 (40.6%) of the potential kidney donors in the study population. Findings were categorized as of high clinical importance in 18 (10.3%) cases, including lung lesions, bowel tumors, and liver tumors and as medium importance in 31 (17.7%). Twenty-two (12.6%) individuals had findings categorized as low importance, probably of no clinical significance and requiring no follow-up. Further potential evaluation of the 49 patients (28%) with highly and moderately significant extrarenal findings may require an additional $6137 (mean $35.1 per each case of all the screened patients). Transplantation of a kidney from a living donor is an excellent alternative to cadaveric allografts. Potential living kidney donors are a highly selected population of healthy individuals, screened for significant past or current medical conditions before undergoing CTA. Despite this screening, potentially significant extrarenal findings (classified as high or medium importance) were revealed in 28% of patients. These patients may require further investigations and/or treatment. The referring physician and patient should be aware of such potentially high probability, which may require further nontransplant related evaluation and treatment. This has medical, legal, economic, and ethical implications.

Is It a Fibroid? Are You Sure?

Uterine fibroids are common benign lesions. Other common benign masses include renal cysts, renal angiomyolipomas, hepatic cysts, hepatic hemangiomas, thyroid cysts, adrenal incidentalomas, pulmonary granulomas and hamartomas, ovarian cysts, and dermoids. All these conditions, especially in asymptomatic patients, almost never have clinical significance. However, it is important to differentiate them from more sinister or even malignant lesions. In general, when a lesion is described as a fibroid, no further evaluation is performed. So if we say that a lesion is a fibroid, we have to be sure. Endometrial fibroids may mimic endometrial polyps or endometrial cancer. Subserous, especially pedunculated fibroids, may need further evaluation to differentiate them from ovarian pathology, colonic pathology, or even müllerian duct anomalies. Pelvic magnetic resonance imaging may be helpful in these cases.

Epidermoid cyst and teratoma of the testis: sonographic and histologic similarities

OBJECTIVE

The classic sonographic description of an epidermoid cyst is a mass with a target or onion ring appearance of alternating rings of hyperechogenicity and hypoechogenicity. This study presents a pathologic-sonographic assessment of classic and nonclassic appearances of an epidermoid cyst of the testis and reports the possible similarity between a classic epidermoid cyst and a teratoma on sonography.

METHODS

We reviewed the sonographic and histologic features of 8 testicular tumors that either had a classic onion ring pattern or were found at pathologic examination to be epidermoid cysts but did not have the classic sonographic pattern.

RESULTS

Three epidermoid cysts had a typical onion ring appearance. Histologic sections of these tumors revealed a squamous epithelial layer lining the cyst and multiple concentric laminated layers of keratin. Two tumors did not have a typical sonographic appearance of epidermoid cysts but were found to be epidermoid cysts at pathologic examination. One was homogeneously hypoechoic, and the other had irregular cystic and solid components, but neither had a target or onion ring appearance. Histologically, both of these tumors consisted of cystic cavities lined by squamous epithelium and contained desquamated keratinized epithelium. Notably, 3 other tumors pathologically diagnosed as teratomas had a sonographic appearance of classic epidermoid cysts. These tumors contained layers of keratin, but the cyst was lined by both squamous cells (ectodermal origin) and cylindrical epithelium (endodermal origin), thereby precluding the diagnosis of epidermoid cysts.

CONCLUSIONS

There is considerable overlapping of the sonographic appearances of teratomas and epidermoid cysts of the testis. Although the onion ring appearance of an intratesticular tumor is suggestive of an epidermoid cyst, this appearance may also be found in cases of a teratoma. Whereas the former condition can be treated by local enucleation, the latter requires radical orchiectomy.

Leydig cell tumors of the testis: gray scale and color Doppler sonographic appearance

OBJECTIVE

To determine the gray scale and color Doppler sonographic features of Leydig cell tumors of the testis in a series of patients.

METHODS

We retrospectively analyzed the sonographic appearance of 10 proven Leydig cell tumors in 9 patients aged 26 to 47 years. Sonographic features that were reviewed included the size and echogenicity of the tumors, presence of cystic areas or calcifications, and distribution pattern of detectable blood flow on color or power Doppler imaging.

RESULTS

The tumors ranged from 0.4 to 3.0 cm in diameter, but most were less than 1.0 cm in diameter. In 1 testis, 2 discrete Leydig cell tumors were found. Nine (90%) of the 10 tumors were homogeneously hypoechoic. Only 1 tumor was isoechoic with the testis. None of the tumors contained calcifications. Of 8 tumors with color Doppler imaging, 7 (88%) showed a characteristic pattern of increased peripheral blood flow, which was either circumferential or punctate. Only 1 tumor was found with internal hypervascularity.

CONCLUSIONS

Peripheral hypervascularity in a hypoechoic testicular tumor that has little or no internal color Doppler flow should suggest the possibility of a Leydig cell tumor, and consideration should be given to testicle-sparing surgery.