Patient presents with right upper quadrant pain.
Monday, November 19, 2018
Case 12 - Triquetral Fracture
Triquetral fractures are the second most common carpal bone fracture, often occurring along the dorsal aspect of the carpal bones. While there are multiple mechanisms for the method of injury, the most common method is impaction from the ulnar styloid, which acts as a chisel, along the dorsal cortex of the triquetrum. Dorsal avulsion injuries are best visualized on the lateral radiograph, as seen in this case, as a result of the strong dorsal ligaments avulsing off the dorsal cortex.
One of my favorite signs in all of radiology is the "Pooping Duck Sign," which is present on the lateral radiograph. The duck is the composed of the superimposition of the Scaphoid and the Lunate bones, while the 'poop' is the avulsed bony fragment of the triquetrum.
Here is a normal lateral radiograph of the wrist with the Pooping Duck sign below.
Nearly all of these fractures are treated non operatively; rarely is any surgery required. As an aside, the skeletal anatomy website by Dr. Richardson is extremely helpful and one I recommend to add to your armamentarium as a quick resource for bony anatomy you might need throughout training.
References:
Case courtesy of Dr Matt Skalski, https://radiopaedia.org/. From the case: https://radiopaedia.org/cases/57109
Radiographic Skeletal Anatomy by Michael L. Richardson, M.D. at the University of Washington:
http://uwmsk.org/RadAnatomy.html
Radiology Tips:
http://radiologytips.com
Triquetral fractures are the second most common carpal bone fracture, often occurring along the dorsal aspect of the carpal bones. While there are multiple mechanisms for the method of injury, the most common method is impaction from the ulnar styloid, which acts as a chisel, along the dorsal cortex of the triquetrum. Dorsal avulsion injuries are best visualized on the lateral radiograph, as seen in this case, as a result of the strong dorsal ligaments avulsing off the dorsal cortex.
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| Case courtesy of Dr. Matt Skalski |
Here is a normal lateral radiograph of the wrist with the Pooping Duck sign below.
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| Courtesy of Dr. Michael L. Richardson, M.D. |
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| Courtesy of Dr. Michael L. Richardson, M.D. |
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| Image Courtesy of Radiology Tips (http://radiologytips.com/modality/radiography/pooping-duck/) |
Nearly all of these fractures are treated non operatively; rarely is any surgery required. As an aside, the skeletal anatomy website by Dr. Richardson is extremely helpful and one I recommend to add to your armamentarium as a quick resource for bony anatomy you might need throughout training.
References:
Case courtesy of Dr Matt Skalski, https://radiopaedia.org/. From the case: https://radiopaedia.org/cases/57109
Radiographic Skeletal Anatomy by Michael L. Richardson, M.D. at the University of Washington:
http://uwmsk.org/RadAnatomy.html
Radiology Tips:
http://radiologytips.com
Monday, November 5, 2018
Case 11 - Trauma, MVC
In most significant trauma, both blunt and penetrating, there will often be multiple findings and you don't want to let satisfaction of search get you. This case demonstrates a minuscule right pneumothorax, with air noted in the anterior costophrenic recess. Subpleural groudglass in the lingula is also present, representing a pulmonary contusion. Additionally, there is a SUBTLE sternal body fracture. This patient also had a couple of subtle, non-displaced rib fractures, but I didn't include those as some of the images on purpose. The things I've seen folks miss the most on trauma are small pneumothoraces, non-displaced rib, sternal, and vertebral body/transverse process fractures, and small mediastinal hematomas. Be sure to always look in these regions for abnormalities. In trauma, I always look at three things on the sagittal series - the sternum, vertebral bodies, and diaphragms looking for injury. If I see a sternal fracture, I will also look at the retrosternal space searching for a hematoma, which can be very small. Reexamining the vessels is also important to assess for underlying vascular injury. I will also run the spine on the axial and coronals looking for transverse process fractures. I've included a link to a good radiographics article for blunt thoracic trauma.
In most significant trauma, both blunt and penetrating, there will often be multiple findings and you don't want to let satisfaction of search get you. This case demonstrates a minuscule right pneumothorax, with air noted in the anterior costophrenic recess. Subpleural groudglass in the lingula is also present, representing a pulmonary contusion. Additionally, there is a SUBTLE sternal body fracture. This patient also had a couple of subtle, non-displaced rib fractures, but I didn't include those as some of the images on purpose. The things I've seen folks miss the most on trauma are small pneumothoraces, non-displaced rib, sternal, and vertebral body/transverse process fractures, and small mediastinal hematomas. Be sure to always look in these regions for abnormalities. In trauma, I always look at three things on the sagittal series - the sternum, vertebral bodies, and diaphragms looking for injury. If I see a sternal fracture, I will also look at the retrosternal space searching for a hematoma, which can be very small. Reexamining the vessels is also important to assess for underlying vascular injury. I will also run the spine on the axial and coronals looking for transverse process fractures. I've included a link to a good radiographics article for blunt thoracic trauma.
Sunday, October 28, 2018
Case 10
This week's case was an example of intrahepatic biliary ductal dilation on ultrasound. We see it so often in other modalities, but it's not as commonly seen on ultrasound, where we are supremely reliant on our technologists. If they don't see it and take an image of it, we usually won't see it. Thankfully, in our protocols, our technologists are supposed to take cine sweeps through any pathology and certain structures, where we might catch things they miss. Always look at the sweeps to look for missed pathology.
Remember this from histology? The portal triad
This week's case was an example of intrahepatic biliary ductal dilation on ultrasound. We see it so often in other modalities, but it's not as commonly seen on ultrasound, where we are supremely reliant on our technologists. If they don't see it and take an image of it, we usually won't see it. Thankfully, in our protocols, our technologists are supposed to take cine sweeps through any pathology and certain structures, where we might catch things they miss. Always look at the sweeps to look for missed pathology.
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| Two anechoic tubular structures, which is abnormal due to the intrahepatic bile duct dilation. |
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| Remember: if you see two hypodense structures surrounding the portal vein, it's periportal edema, and it will extend along all branches of the portal vein. If you look at the left portal vein branch in this image, there is only 1 hypodense structure along the posterior aspect of the portal vein, meaning this is bile duct dilation. |
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| The CBD is also dilated. In this patient, this was all an expected sequela of prior cholecystectomy. |
Sunday, October 14, 2018
Case 9
This case demonstrates pneumoperitoneum, which was missed by a staff radiologist. When I saw this study, the first thing to catch my eye was the large lucency over the liver (star), especially since this was a supine radiograph. On a supine radiograph, you have to look for gas rising non-dependently along the anterior abdominal wall resulting in a "lucent liver sign." Additionally, as most of the answers noted, there is free air revealing itself as a Rigler sign in the left hemiabdomen. There is a segment of small bowel where you can see both surfaces of the bowel wall - intraluminal and serosal surface (arrow). Turns out, this was a case of a perforated sigmoid cancer.
Radiopedia has a great list of all of the different signs of pneumoperitoneum and being familiar with them will help you in cases where you might not have a classic Rigler sign or an upright chest radiograph with subdiaphragmatic free air.
This case demonstrates pneumoperitoneum, which was missed by a staff radiologist. When I saw this study, the first thing to catch my eye was the large lucency over the liver (star), especially since this was a supine radiograph. On a supine radiograph, you have to look for gas rising non-dependently along the anterior abdominal wall resulting in a "lucent liver sign." Additionally, as most of the answers noted, there is free air revealing itself as a Rigler sign in the left hemiabdomen. There is a segment of small bowel where you can see both surfaces of the bowel wall - intraluminal and serosal surface (arrow). Turns out, this was a case of a perforated sigmoid cancer.
Radiopedia has a great list of all of the different signs of pneumoperitoneum and being familiar with them will help you in cases where you might not have a classic Rigler sign or an upright chest radiograph with subdiaphragmatic free air.
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| Sigmoid wall thickening with an abscess in the right anterior pelvis. |
Sunday, October 7, 2018
Case 8 - "Locked Facets" (Cervical Spine Facet Joint Dislocation)
This case demonstrates bilateral cervical spine facet joint dislocation, which is commonly called jumped or locked facets. Facet joint subluxation, perched facets, or locked facets all fall under the hyperflexion type of injury and can be unilateral or bilateral. When there is true facet joint dislocation, as was present in this case, you also have a translational injury as noted by the anterolisthesis of C6 on C7. In the setting of cervical spine trauma, a lot of trauma centers are performing a CTA of the neck as their initial cervical spine evaluation in order to asses for bony injury and associated vascular injury. If not performed, this patient would require a CTA of the neck as well.
When evaluating the cervical spine in the setting of trauma, I always start with the sagittal series because I want to be most attuned to looking for facet joint alignment and widening of the posterior elements of the spine, which is often quite subtle, more so than perched or locked facets. Facets are considered subluxed when there is less than 50% overlap of the articular surfaces or there is more than 2mm of diastasis.
For further reading, this is a great radiographics article, which further describes cervical spine trauma and also delves into the SLIC morphology score for surgical vs. nonsurgical management.
MDCT of Blunt Cervical Spine Trauma in Adults (Dreizin, et al)
This case demonstrates bilateral cervical spine facet joint dislocation, which is commonly called jumped or locked facets. Facet joint subluxation, perched facets, or locked facets all fall under the hyperflexion type of injury and can be unilateral or bilateral. When there is true facet joint dislocation, as was present in this case, you also have a translational injury as noted by the anterolisthesis of C6 on C7. In the setting of cervical spine trauma, a lot of trauma centers are performing a CTA of the neck as their initial cervical spine evaluation in order to asses for bony injury and associated vascular injury. If not performed, this patient would require a CTA of the neck as well.
When evaluating the cervical spine in the setting of trauma, I always start with the sagittal series because I want to be most attuned to looking for facet joint alignment and widening of the posterior elements of the spine, which is often quite subtle, more so than perched or locked facets. Facets are considered subluxed when there is less than 50% overlap of the articular surfaces or there is more than 2mm of diastasis.
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| Normal facet articulation on the axial images - the facet look like a hamburger with two 'bony buns' |
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| Reverse Hamburger Bun Sign - the facets are dislocated |
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| Locked Facets - The red lines show where the superior and inferior facets should be articulating. |
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| The arrows show the areas of bony avulsion from the vertebral body, which was ripped of by the anterior and longitudinal ligaments. |
MDCT of Blunt Cervical Spine Trauma in Adults (Dreizin, et al)
Monday, September 24, 2018
Case 7
Nice case of renal vein thrombosis (RVT). Whenever you look at the kidneys, and notice that one side is asymmetrically enlarged, make sure to look at the parenchyma to evaluate its enhancement. Remember - you have a control side (the other kidney), which will often be normal. In this case, the left kidney has delayed enhancement with perinephric stranding. Unfortunately, one of our guys missed the renal vein thrombosis and called this pyelonephritis.
Honestly, I think vascular structures outside of the Aorta are blind spots on CT for most radiologists, especially if it's not a CTA or CTV. Start including the other vascular structures (portal vein, mesenteric and renal vessels, and iliac veins) in your search pattern now so that you can buzz through them on every case looking for hidden abnormalities.
RVT is, much like portal vein thrombosis, related to either bland or tumor thrombus. In this case, there was no renal tumor present (other than some simple cysts), so this was a bland thrombus. According to radiopedia, the majority of bland thrombi are related to hypercoaguability from nephrotic syndrome (something I didn't know!), but I have most commonly seen thrombus in renal cell carcinoma and post trauma. The thrombus can break off and result in pulmonary embolism, so keep that complication in your back pocket. If you aren't sure if the vein is thrombosed, a renal doppler ultrasound would be a quick and helpful exam.
Nice case of renal vein thrombosis (RVT). Whenever you look at the kidneys, and notice that one side is asymmetrically enlarged, make sure to look at the parenchyma to evaluate its enhancement. Remember - you have a control side (the other kidney), which will often be normal. In this case, the left kidney has delayed enhancement with perinephric stranding. Unfortunately, one of our guys missed the renal vein thrombosis and called this pyelonephritis.
Honestly, I think vascular structures outside of the Aorta are blind spots on CT for most radiologists, especially if it's not a CTA or CTV. Start including the other vascular structures (portal vein, mesenteric and renal vessels, and iliac veins) in your search pattern now so that you can buzz through them on every case looking for hidden abnormalities.
RVT is, much like portal vein thrombosis, related to either bland or tumor thrombus. In this case, there was no renal tumor present (other than some simple cysts), so this was a bland thrombus. According to radiopedia, the majority of bland thrombi are related to hypercoaguability from nephrotic syndrome (something I didn't know!), but I have most commonly seen thrombus in renal cell carcinoma and post trauma. The thrombus can break off and result in pulmonary embolism, so keep that complication in your back pocket. If you aren't sure if the vein is thrombosed, a renal doppler ultrasound would be a quick and helpful exam.
Monday, September 17, 2018
Case 6
The sonographer called this a lesion, and from the answers I got this week, most knew it wasn't a real lesion, but weren't sure what to call it. This is an example of a renal junctional parenchymal defect, which is a normal variant. They will be triangular, echogenic foci in the renal cortex, sometimes with an echogenic tract from the cortex into the renal sinus fat. Generally, they are located between the upper pole and interpolar region of the kidney, but can be seen in the lower pole as well, as they are formed from incomplete embryologic fusion of the renal poles. Oftentimes, it is confused for a renal cortical scar or an angiomyolipoma.
The sonographer called this a lesion, and from the answers I got this week, most knew it wasn't a real lesion, but weren't sure what to call it. This is an example of a renal junctional parenchymal defect, which is a normal variant. They will be triangular, echogenic foci in the renal cortex, sometimes with an echogenic tract from the cortex into the renal sinus fat. Generally, they are located between the upper pole and interpolar region of the kidney, but can be seen in the lower pole as well, as they are formed from incomplete embryologic fusion of the renal poles. Oftentimes, it is confused for a renal cortical scar or an angiomyolipoma.
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