BOWEL WALL THICKENING

How to differentiate bowel wall thickening due to different causes ?

Bowel wall thickening may be classified as follows with possible etiologies

Focal	<5 cm	Irregular and asymmetrical thickening	Malignancy (Exceptions: Crohn’s / Tuberculosis)
Focal	<5 cm	Regular, symmetric and homogeneous wall thickening- No fat stranding	Small and well differentiated adenocarcinoma/ lymphoma
Focal	<5 cm	Regular, symmetric and homogeneous wall thickening- With fat stranding	Diverticulitis, Epiploic Appendagitis, Omental Infarction and Appendicitis
Segmental	6-40 cm		Ischaemic, inflammatory or infectious conditions (Exception: Lymphoma)
Diffuse	>40 cm		Ischaemic, inflammatory or infectious conditions (Exception: Lymphoma)

References:

Fernandes, T., Oliveira, M.I., Castro, R. et al. Bowel wall thickening at CT: simplifying the diagnosis. Insights Imaging 5, 195–208 (2014). https://doi.org/10.1007/s13244-013-0308-y

Speech box Sign

Physiological peritoneal fluid herniating through capacious femoral ring manifests an appearance similar to a speech bubble/speech box on ultrasound imaging .

This is an invaluable sonographic sign for identifying clinically occult femoral hernias and differentiating them from inguinal hernias and cysts of the canal of Nuck in females 

References;

Thaker, S., Botchu, R. & Gupta, H. Sonographic “speech bubble/speech box sign” in clinically occult femoral hernias: ultrasound findings and anatomical basis. J Ultrasound 24, 361–366 (2021). https://doi.org/10.1007/s40477-020-00484-5

Can acute cholecystitis be diagnosed without gallbladder wall thickening, pericholecystic fluid/wall edema, or a sonographic Murphy’s sign?

 

Because of its widespread availability and high diagnostic accuracy, ultrasound is generally considered the initial test of choice for gall bladder disease evaluation

The classic ultrasound findings of cholecystitis include a sonographic Murphy’s sign, a thickened gallbladder wall, gallbladder wall edema, gallbladder hydrops, and pericholecystic fluid.  

Stone in the neck (SIN), defined as an immobile stone lodged in the neck of the gallbladder without anechoic space between the neck and stone it contains has been found to be highly suggestive of cholecystitis even in the absence of any other ultrasonographic signs of infection.  

The sensitivity of the SIN phenomenon was 56.52%. The specificity was 97.06% (84.67–99.93). The positive and negative predictive values were 92.86% (66.13–99.82) and 76.74% (61.37–88.24), respectively.

References:

Nelson, M., Ash, A., Raio, C. et al. Stone-In-Neck phenomenon: a new sign of cholecystitis. Crit Ultrasound J 3, 115–117 (2011). https://doi.org/10.1007/s13089-011-0071-6

 

 

When to worry about the endometrial thickness in postmenopausal women?

Postmenopausal patients who present with vaginal bleeding should undergo transvaginal US.

Endometrial thickness >5 mm in postmenopausal women not receiving hormone replacement therapy is abnormal

Endometrial thickness >8 mm in patients receiving hormone replacement therapy or tamoxifen therapy) is abnormal (1).

If Transvaginal ultrasonography images reveal a thin endometrial echo (less than or equal to 4 mm), on initial evaluation of postmenopausal bleeding, it is usually sufficient to stop investigation, given that an endometrial thickness of 4 mm or less has a greater than 99% negative predictive value for endometrial cancer (2).

A thin, distinct echo - less than or equal to 4 mm in an average-risk woman, or less than 3 mm in virtually any woman.  excludes significant tissue. 

Reference:

1. Gupta A, Desai A, Bhatt S. Imaging of the Endometrium: Physiologic Changes and Diseases: Women's Imaging. Radiographics. 2017 Nov-Dec;37(7):2206-2207. doi: 10.1148/rg.2017170008. PMID: 29131769.

2. https://www.acog.org/clinical/clinical-guidance/committee-opinion/articles/2018/05/the-role-of-transvaginal-ultrasonography-in-evaluating-the-endometrium-of-women-with-postmenopausal-bleeding

ECG-gated CT examinations essential for assessing atherosclerotic burden?

Chest CT images obtained without ECG gating for non-cardiac indications show comparable performance for the detection of coronary artery calcification as that of dedicated ECG-gated CT examinations. It can be used as an imaging biomarker for assessing atherosclerotic burden.

Reference:

1. Kay FU, Oz OK, Abbara S, Mortani Barbosa EJ Jr, Agarwal PP, Rajiah P. Translation of Quantitative Imaging Biomarkers into Clinical Chest CT. Radiographics. 2019 Jul-Aug;39(4):957-976. doi: 10.1148/rg.2019180168. Epub 2019 Jun 14. PMID: 31199712.

Imaging findings to differentiate Mass-forming Pancreatitis and Pancreatic Malignancy

 

Imaging findings	Mass-forming Pancreatitis	Pancreatic Malignancy
Duct-penetrating sign	Smooth narrowing of pancreatic duct which is seen traversing  a pancreatic mass without obstruction strongly favors the diagnosis of an inflammatory mass   The duct may be smoothly narrowed or of normal caliber.   The duct-penetrating sign is 96% specific for an inflammatory pancreatic mass, with sensitivity of 85% and accuracy of 94%.	Not seen
Collateral Duct Dilatation	Collateral duct or side-branch dilatation in the uninvolved or distal pancreas supports an inflammatory cause   Dilatation of pancreatic duct side branches is thought to be due to a traction effect from fibrosis in a patient with chronic pancreatitis.	Not seen
Displaced Calcifications in Chronic Pancreatitis	Usually absent	Peripheral displacement of pancreatic parenchymal calcifications commonly seen in chronic pancreatitis calcifications may indicate a new underlying malignancy
Double Duct Sign	The double duct sign is nonspecific and can develop secondary to inflammatory processes in the pancreas as well as other nonmalignant conditions	Simultaneous dilatation of the common bile duct and pancreatic duct, known as the double duct sign favors a malignant lesion   Seen in malignancies involving the head of the pancreas in up to 77% cases
Duct-to-Parenchyma Ratio	Usually < 0.34	Pancreatic duct-to-parenchyma ratio of greater than 0.34 strongly favors malignancy.   It is due to marked upstream pancreatic ductal dilatation with marked parenchymal atrophy, which are the imaging hallmarks of pancreatic adenocarcinoma
Vessel Encasement and Vessel Deformity	Uncommon but may be seen in inflammatory conditions such as autoimmune pancreatitis	Soft-tissue attenuation that encases the adjacent vasculature is highly suggestive of the extra glandular spread of pancreatic adenocarcinoma and is crucial in determining tumor resectability.   SMV teardrop sign, a teardrop-shaped deformity of the SMV, is highly indicative of SMV encasement
SMA-to-SMV Ratio	< 1 in acute pancreatitis	> 1 in malignancy. Not sensitive or specific.

 

Reference:

1. Wolske KM, Ponnatapura J, Kolokythas O, Burke LMB, Tappouni R, Lalwani N. Chronic Pancreatitis or Pancreatic Tumor? A Problem-solving Approach. Radiographics. 2019 Nov-Dec;39(7):1965-1982. doi: 10.1148/rg.2019190011. Epub 2019 Oct 4. PMID: 31584860.