Saber sheath trachea: A radiological sign of severe airway obstruction

A middle-aged man, chronic smoker, presented with complaints of productive cough & exertional breathlessness (mMRC grade III) for 3 years with frequent episodes of exacerbation in the past. There was no other comorbidity or significant past history. His chest radiograph showed narrowing of trachea. Evaluation with computerized tomography of thorax showed normal extra-thoracic trachea with narrowing of the coronal diameter with increase in the sagittal diameter of the trachea along with thickening and calcification of the tracheal wall seen in saber sheath trachea. Keywords: forced expiratory volume; tracheal narrowing; saber sheath trachea.

The “Inside-outside” Sign

We describe a radiological sign, “inside-outside sign,” observed during the cannulation of an expandable contrast-filled tubular structure in the human body. In this optical illusion, a catheter or guidewire appears to be outside the lumen when it is inside the lumen in reality. Knowing this rare optical illusion is essential to avoid mistaking it for a catheter or guidewire outside the lumen.

Gas-containing renal stones: a red flag for renal infection

Background Gas in the renal excretory system is described as a consequence of recent procedures but it can be a sign of severe conditions such as fistulas or infections; however, gas-containing renal stones are only rarely encountered. Purpose To describe the association of gas-containing renal stones and urinary tract infection. Material and Methods We performed a retrospective evaluation of the clinical and imaging findings in a series of six patients with gas-containing renal stones and compared our findings with those of patients with gas-containing renal stones reported in the literature. Urine and stone cultures were used as a diagnostic standard for urinary tract infection. Results Including the present series, there is a total of 21 patients with gas-containing renal stones in the literature. Based on clinical presentation, urinary tract infection could be suspected in 10 (57%) patients, while urine and/or stone cultures showed infection in 18 of 19 (95%) patients, with only one case with no bacterial growth in both (5%); in the remaining patient the information was not available. Conclusion Gas-containing renal stones are a rarely reported entity usually diagnosed with computed tomography. They are a radiological sign often associated with urinary tract infection that can also be encountered in patients with non-specific renal symptoms.

T2-FLAIR mismatch sign: a roadmap of pearls and pitfalls

T2-FLAIR mismatch sign has been advocated to be 100% specific for IDH-mutant 1p/19q non-codeleted gliomas (diffuse astrocytomas). However, false positives have been reported in recent works. Loose application of the criteria may lead to erroneous classification, especially by non-trained neuroradiologists. In this pictorial essay, we aim to bring attention to the need for strict criteria for the application of T2-FLAIR mismatch sign and to discuss the potential pitfalls in the application of these criteria. For that, a series of adult brain tumour cases are presented to demonstrate how to apply this radiological sign in the clinical practice.

Bilateral Severe Genu Varum in Dyggve-Melchior-Clausen Syndrome – A Case Report

Introduction: Dyggve-Melchior-Clausen (DMC) syndrome was described in 1962 as an autosomal recessive type of spondyloepimetaphyseal dysplasia associated with mental retardation. Dymeclin (DYM) gene on chromosome 18q12.1 that encodes for DYM protein which is expressed in cartilage, bone, and brain is mutated in DMC. Case Report: A 6 year -old male child presented with bilateral gradually progressive genu varum deformity of 4 years’ duration. There was no significant past medical and family history. A plain radiograph of his knee, pelvis, and spine shows some classical signs of skeletal dysplasia. A plain radiograph of the pelvis with both hips shows a classical semilunar, irregular lacy appearance around the iliac crest which is a pathognomonic radiological sign of this syndrome. Conclusion: The radiographic lacy appearance of iliac crests and generalized platyspondyly with double-humped end plates are pathognomonic of DMC. Keywords: Genu varum, Dyggve-Melchior-Clausen syndrome, spondyloepimetaphyseal dysplasia.