Restoration of strength despite low stress and abnormal imaging after Achilles injury.

PURPOSE: To determine the usefulness of clinical imaging in predicting the mechanical properties of rabbit Achilles tendons after acute injury. METHODS: We created a 2 x 7-mm full-thickness central tendon defect in one Achilles tendon of healthy rabbits. Rabbits in groups of 10 were killed immediately and 4 and 8 wk after surgery (n = 30). We then performed magnetic resonance (MR) imaging, ultrasonography (US), bone mineral densitometry (BMD), and mechanical testing to failure using a dual-cryofixation assembly on experimental and contralateral tendons. The main outcome measures included tendon dimensions, optical density (OD) of T1-weighted, proton density (PD), and T2-weighted MR sequences, US focal abnormalities, BMD of the calcaneus, and stress and peak load to failure. RESULTS: On MR imaging and US, all dimensions of the injured tendons after 2 wk and more were greater than those of the contralateral tendons (P < 0.05). The mean T1-weighted OD was greater at 4 wk (256 +/- 53) and 8 wk (184 +/- 24) than immediately after surgery (149 +/- 15). Mechanical stress was markedly lower in the experimental than in the contralateral tendons at both 4 wk (39 +/- 9 vs 77 +/- 16 N x mm(-2)) and 8 wk (58 +/- 6 vs 94 +/- 26 N x mm(-2); P < 0.05). Mean peak load to failure was significantly lower immediately after surgery (332 +/- 128 N) than at 4 and 8 wk (712 +/- 106 and 836 +/- 90 N, respectively). Both high T1-weighted OD (r = -0.73) and PD OD (r = -0.69) correlated with lower mechanical stress (P < 0.05). In the experimental tendons, higher T1-weighted OD correlated with lower peak load (r = -0.46; P < 0.05). CONCLUSIONS: Normal peak loads 4 wk after injury were withstood by an enlarged tendon of lower stress. These findings support progressive physical loading 4 wk after an Achilles tendon injury. T1-weighted OD constituted a marker of tendon mechanical recovery.

A clinical and radiologic review of uncommon types and causes of pancreatitis.

Acute pancreatitis is one of the most common conditions for which emergent imaging is indicated. Alcohol consumption and cholelithiasis are the most common causes of acute pancreatitis in adults, whereas the majority of cases in children are idiopathic or secondary to trauma. A wide variety of structural and biochemical abnormalities may also cause pancreatitis. Although in some cases it is difficult to identify the specific cause of the disease radiologically, certain uncommon types of acute or chronic pancreatitis may have unique imaging features that can help the radiologist make an accurate diagnosis. These unusual types include autoimmune pancreatitis, groove pancreatitis, tropical pancreatitis, hereditary pancreatitis, and pancreatitis in ectopic or heterotopic pancreatic tissue. Pancreatitis may occasionally be seen in association with cystic fibrosis or pancreas divisum, or secondary to worm infestation of the pancreaticobiliary tree (eg, by Ascaris lumbricoides). In addition, primary pancreatic and duodenal masses may occasionally manifest as acute or recurrent acute pancreatitis. Knowledge of the classic imaging findings of these entities allows prompt recognition of the relevant pathologic condition, thereby preventing misdiagnosis and subsequent inappropriate or delayed management.

The ability of ultrasonography, magnetic resonance imaging and bone mineral densitometry to predict the strength of human Achilles' tendons.

OBJECTIVE: To assess the value of ultrasonography (US), magnetic resonance imaging (MRI), and bone mineral densitometry (BMD) in evaluating human Achilles' tendon strength. DESIGN: Cross-sectional observational study. SETTING: Tertiary care hospital. PARTICIPANTS: Ninety-eight Achilles' tendons from 49 consecutive cadavers (26 men and 23 women with a mean age of 66.6 years) undergoing hospital autopsy were assessed. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Tendon dimensions on US and MRI, and T1-weighted optical density were measured. Areas of hypodensity, hyperdensity, calcification, and heterogeneity were identified on US. The BMD of each calcaneus was recorded. The tendons were mechanically tested to determine peak load at failure. RESULTS: Sixteen patients (32.7%, 27 tendons) had abnormalities in 1 or both tendons on US and/or MRI (17 on US, 17 on MRI). Fifty-seven tendons (58%) ruptured in their midsubstance, at an average peak load of 4722+/-990N. Tendons with and without abnormalities on imaging had similar strengths (P>.05). Calcaneal BMD correlated weakly with peak load at failure (r=.21, P<.05). CONCLUSIONS: The prevalence of Achilles' tendons abnormalities on US or MRI was 32.7% in our study group. Abnormalities on clinical imaging (US or MRI) were not predictive of the load at failure. Therefore, tendons with imaging abnormalities are not necessarily weaker, and one cannot predict the likelihood of rupture based on imaging results. Further, higher-powered studies could explore the ability of BMD to detect minimal clinically important differences and to predict Achilles' tendon weakness.

Liposuction sepsis - be alert.

Postoperative infection in liposuction patients may be exceedingly difficult to clinically appreciate because of the skin edema, colour changes and even blistering that can occur. The authors outline such a case with practical advice about establishing an accurate and precise diagnosis of an early septic process.

Leiomyomas beyond the uterus: unusual locations, rare manifestations.

Uterine leiomyomas affect 20%-30% of women older than 35 years. Extrauterine leiomyomas are rarer, and they present a greater diagnostic challenge: These histologically benign tumors, which originate from smooth muscle cells, usually arise in the genitourinary tract (in the vulva, ovaries, urethra, and urinary bladder) but may arise in nearly any anatomic site. In addition, unusual growth patterns may be seen, including benign metastasizing leiomyoma, disseminated peritoneal leiomyomatosis, intravenous leiomyomatosis, parasitic leiomyoma, and retroperitoneal growth. In the presence of such a pattern, a synchronous uterine leiomyoma or a previous hysterectomy for removal of a primary uterine tumor may be indicative of the diagnosis. However, some extrauterine leiomyomas may mimic malignancies, and serious diagnostic errors may result. The most useful modalities for detecting extrauterine leiomyomas are ultrasonography, computed tomography, and magnetic resonance (MR) imaging. The superb contrast resolution and multiplanar capabilities of MR imaging make it particularly valuable for characterizing these tumors, which usually show low signal intensity similar to that of smooth muscle on T2-weighted images. The radiologist's recognition of this and other characteristic features may help steer the clinician toward timely, appropriate management and away from unnecessary, potentially harmful treatment.

Comparative anatomy of rabbit and human achilles tendons with magnetic resonance and ultrasound imaging.

We sought to describe the comparative anatomy of the Achilles tendon in rabbits and humans by using macroscopic observation, magnetic resonance imaging, and ultrasonography. The calcaneus-Achilles tendon-gastrocnemius-soleus complexes from 18 New Zealand white rabbits underwent ultrasound (US) and magnetic resonance (MR) imaging and gross anatomic sectioning; these results were compared with those from a cadaveric gastrocnemius-soleus-Achilles tendon-calcaneus specimen from a 68-y-old human male. The medial and lateral gastrocnemius muscle tendons merged 5.2 +/- 0.6 mm proximal to the calcaneal insertion macroscopically, at 93% of their course, different from the gastrocnemius human tendons, which merged at 23% of their overall course. The rabbit flexor digitorum superficialis tendon, corresponding to the flexor digitorum longus tendon in human and comparable in size with the gastrocnemius tendons, was located medial and anterior to the medial gastrocnemius tendon proximally and rotated dorsally and laterally to run posterior to the Achilles tendon-calcaneus insertion. In humans, the flexor digitorum longus tendon tracks posteriorly to the medial malleolus. The soleus muscle and tendon are negligible in the rabbit; these particular comparative anatomic features in the rabbit were confirmed on the MR images. Therefore the rabbit Achilles tendon shows distinctive gross anatomical and MR imaging features that must be considered when using the rabbit as a research model, especially for mechanical testing, or when generalizing results from rabbits to humans.