Nonspecificity of the "rim sign" in the scintigraphic diagnosis of missed testicular torsion

Causes of a hyperemic peritesticular rim on dynamic and static scintigrams are reviewed. Of 6 patients exhibiting such a pattern, 3 had missed testicular torsion; the other 3 had tumor, trauma, or inflammation. The authors conclude that a hyperemic peritesticular rim is a nonspecific finding reflecting underlying pathophysiological changes and is not pathognomonic of missed torsion.     

"Dural tail sign": a specific MR sign for meningioma?

Somewhat conflicting reports have appeared about the significance of linear meningeal thickening and enhancement adjacent to peripherally located cranial mass lesions on contrast enhanced magnetic resonance images. Some authors consider this finding nearly diagnostic of meningioma. In an attempt to determine the specificity of this so-called tail sign, particularly with respect to meningioma, we retrospectively reviewed 16 cases from institutional records. From our results, the tail sign appears to be highly suggestive but not specific for meningioma.     

"To-and-fro" waveform in the diagnosis of arterial pseudoaneurysms

Medical ultrasound imaging with Doppler plays an essential role in the diagnosis of vascular disease. This study intended to review the clinical use of “to-and-fro” waveform at duplex Doppler ultrasonography (DDU) in the diagnosis of pseudoaneurysms in the arterial vessels of upper and lower extremities, abdominal aorta, carotid and vertebral arteries as well as to review our personal experiences of “to-and-fro” waveform at DDU also. After receiving institutional review board approval, an inclusive literature review was carried out in order to review the scientific foundation of “to-and-fro” waveform at DDU and its clinical use in the diagnosis of pseudoaneurysms in various arterial vessels. Articles published in the English language between 2000 and 2013 were evaluated in this review study. Pseudoaneurysms in arterial vessels of the upper and lower extremities, abdominal aorta, carotid and vertebral arteries characterized by an extraluminal pattern of blood flow, which shows variable echogenicity, interval complexity, and “to-and-fro” flow pattern on color Doppler ultrasonography. In these arterial vessels, Duplex ultrasonography can demonstrate the degree of clotting, pseudoaneurysm communication, the blood flow patterns and velocities. Spectral Doppler applied to pseudoaneurysms lumen revealed systolic and diastolic turbulent blood flow with traditional “to-and-fro” waveform in the communicating channel. Accurate diagnosis of pseudoaneurysm by spectral Doppler is based on the documentation of the “to-and-fro” waveform. The size of pseudoaneurysm determines the appropriate treatment approach as surgical or conservative.     

CT of intracranial tuberculomas with specific reference to the “target sign”

Summary The CT appearances of 30 patients with a total of 58 intracranial tuberculomas are discussed. Of specific interest in this study is the relatively high incidence of patients who presented with the target sign. To date there has been only 1 report of 4 cases with this appearance on CT. Four basic patterns of post contrast enhancement are described. As suggested by Welchman [1] this study concludes that the target sign is pathognomonic of an intracranial tuberculoma.     

Pathologic significance of the "dural tail sign"

Objective

The exact nature of the “dural tail sign” (thickening of the dura adjacent to the tumour in contrast enhanced T1-MRI imaging) is still not clearly established. In this study we tried to verify the histological appearance of the “dural tail sign” and probable correlation between different MRI findings and dural tail histology.

Material and methods

In this study, 129 patients with intracranial lesions underwent MRI imaging with 1.5 T scanner. The “dural tail sign” was defined using Goldsher et al. criteria. Size and pattern of enhancement of the tumour and adjacent dura was noted in MRI and in the pathologic samples, dural tail and the dura beneath the tumour was assessed.

Results

In 30 cases, “dural tail sign” was evident on MRI, dural tail noted in 17 of these cases in histological samples (12 meningiomas, 3 pituitary adenomas and 2 schwannomas). All of them had vessel dilatation, 6 showed tumoural invasion, 4 demonstrated intravascular growth of the lesion and 1 showed inflammation of the dura.

Conclusion

In our study MRI findings failed to predict tumoural invasion of the dural tail in histologic samples and because of frequent presence of tumour nests in it, the dura matter should be resected as widely as possible.     

Scintigraphic skeletal "doughnut" sign due to giant cell tumor of the fibula

Although the "doughnut" sign in brain scintigraphy is a well known phenomenon, similar findings have recently been reported in bone scintigraphy in osseous and nonosseous lesions. A skeletal doughnut sign in bone scintigraphy caused by giant cell tumor of the proximal fibula is presented with a brief review of literature.     

The "inverted V" sign of pneumoperitoneum

On the supine radiograph, an inverted "V" may be seen over the pelvis in a patient with pneumoperitoneum. While in infants this is produced by the umbilical arteries, in adults it appears to be created by the inferior epigastric vessels.     

The “target sign”: is it a specific sign of CNS tuberculoma?

In brain lesions, the target sign has been defined as a central nidus of calcification or central enhancement surrounded by a ring of enhancement. It has been considered a pathognomonic finding of central nervous system (CNS) tuberculoma. The purpose of this report is to demonstrate that the target sign related to central enhancement is a nonspecific finding and may lead to erroneous diagnosis of CNS tuberculoma.     

Posttraumatic tension pneumopericardium: the "small heart" sign

Radiographic measurements of the cardiothoracic ratio in four adult victims of blunt thoracic trauma with pneumopericardium demonstrated a sudden, substantial decrease in the size of the cardiac silhouette, which was accompanied by pathophysiologic effects of cardiac tamponade. The sudden decrease in cardiac size could not be attributed to a decrease in intravascular volume or to changes in positive airway pressure. Following surgical relief of tension pneumopericardium, the cardiac size was restored to baseline dimensions and the hemodynamic effects of tamponade resolved. In the presence of pneumopericardium, the "small heart" sign may alert one to the presence of tension pneumopericardium and impending cardiac tamponade.     

MR evaluation of the "arcuate" sign of posterolateral knee instability

OBJECTIVE: The purpose of this study was to evaluate associated knee injuries using MR imaging in patients with the "arcuate" sign, a term referring to avulsion fracture of the proximal fibula on conventional radiographs. MATERIAL AND METHODS: MR imaging of 18 cases (17 patients, both knees in one patient) with the arcuate sign on conventional radiographs was retrospectively interpreted to evaluate the associated meniscal, ligamentous, and bony injuries. In 12 cases, MR findings were correlated with surgical results. RESULTS: In all cases, avulsed bony fragments from the proximal pole of the fibula were attached to the fibular collateral ligament, the biceps femoris tendon, or both. Tear of the posterolateral capsule was seen in 12 cases (67%). Injury of the cruciate ligaments was noted in 16 cases (89%): injury to both the anterior cruciate ligament and posterior cruciate ligament was seen in nine cases (50%), injury to only the anterior cruciate ligament was seen in four, and injury to the posterior cruciate ligament only was noted in three. Bone bruises or gross fractures were seen in all cases: bone bruises on the anteromedial femoral condyle were noted in nine cases (50%) and were seen on the anteromedial tibial condyle in five cases (28%). Tear of the medial meniscus was seen in five cases (28%) and tear of the lateral meniscus in four cases (22%). Injury to the popliteus was seen in six cases (33%). Joint effusion was associated in all cases. CONCLUSION: MR imaging is useful for evaluation of associated soft-tissue injuries in patients with the arcuate sign on conventional radiographs. Avulsion injury to the proximal fibula is an important indicator of the internal derangement of the knee and for predicting the mechanism of an injury with varus stress. Cruciate ligament tear and bone bruises on the anteromedial condyle of the femur and tibia are common associated findings.     

The "ring sign" of necrotic pheochromocytoma.

Pheochromocytomas are usually hypervascular tumors exhibiting dense stain during angiography. The cystic nature of the neoplasm or tumor necrosis can result in failure of opacification of the mass or a central lucent area. Four cases of pheochromocytoma are described where a central avascular zone was surrounded by a dense rim of contrast, giving a "ring sign." Since this appearance is best seen in the capillary and venous phases, delayed films are essential.