Uterine Arteriovenous Malformation - USG Doppler

Gray scale trans abdominal longitudinal view Ultrasonography of uterus in a 34 year old female showing multiple an-echoic areas within the myometrum of the anterior wall (arrow) displacing the thin linier endometrium (arrow head).

On colour Doppler there are multiple colour filled dilated vascular channels.

Power Doppler depicting the color flow within the lesion

Spectral wave form at the feeding artery showing high velocity and relatively high resistant arterial flow.

Spectral tracing in the draining vein showing venous flow. The findings are consistent with uterine arteriovenous fistula. Patient had history of recent medical termination of pregnancy with dilatation of curettage.

Discussion:

Uterine vascular malformations include:

• Arteriovenous malformations (AVM) (especially arteriovenous fistulas).
• True aneurysms.
• Pseudoaneurysms. 

Uterine AVMs are rare in nonpregnant women.
It is otherwise called with several terms which are cavernous hemangioma, cirsoid aneurysm, racemose aneurysm, arteriovenous aneurysm, pulsatile angioma, and arteriovenous fistula.

Etiology:
AV fistulas are usually acquired and typically represent a single artery joining a single vein.
They result as a consequence of previous uterine trauma (eg, prior pelvic surgery, curettage), use of intrauterine contraceptive devices, pathologic pregnancy-related events, and previous treatment for gestational trophoblastic disease.

Clinical Features:
Vaginal bleeding- Most common.
Congestive heart failure - secondary to steal phenomenon - Less common.

Imaging findings:

USG:

• Gray-scale US shows a normal-appearing endometrium, whereas the myometrium contains multiple hypoechoic or anechoic spaces.
• At color Doppler US, these cystic spaces generate color signals in a mosaic pattern representing turbulent flow.
• Spectral analysis of the arterial vessels within the lesion shows high-velocity flow with a low resistive index (approximately 0.51–0.65). Spectral analysis of venous flow demonstrates a similar pattern.

CT: CT angiography of the pelvic vessels may reveal the vascular malformation.

MRI:
Multiple dilated tubular channels showing flow related signal voids (hypointense) on T1 and T2 images seen in myometrium with normal endometrium or displaced endometrium. The flow relted signal void channels may or may not extend in to the parametrium.

Treatment:

• Acute treatment - Hemodynamic stabilization and management of active bleeding. 
• Occlusion with a Foley catheter bulb may be effective. 
• If fertility is not an issue, hysterectomy is the treatment of choice 
• They may be treated successfully with intra-arterial embolization

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Ovarian Dermoid - CT

CT scan axial section in a 28 Year old female with pain abdomen since 2 years showing well defined predominantly fat density round mass lesion seen in the pelvis in the mid line and  towards right side with areas of calcification (Rokintasky protruberence), soft tissue and fluid components in the dependent part. Features are consistent with dermoid. 

Discussion:

A term dermoid is used now a days instead of teratomas which derived from more than one germ layer. 

The contents of the dermoid include hair, teeth, fat, skin, muscle, endocrine tissue and ectodermal tissue predominates among these.

• Mature cystic teratomas are commonly referred as dermoid cysts.
• They are most common ovarian neoplasm.
• Mature cystic teratomas of the ovary is invariably benign. Rarely (1-3%) my undergo malignant. Prognosis is poor for such tumors.

Age: Can occur at any age. More common during reproductive age (16-55) and peak at 20-40. 50% of adnexal neoplasms are dermoid during adolescence. 

Location:  Most commonly ovary, bilateral in 8-25%.

Other locations: Mediastinum, retroperitoneum, cervical region, brain

Clinical findings: Frequently incidentally detected.

• Abdominal pain as in our patient.
• Mass
• Abnormal uterine bleeding.
• Back pain.
• Bladder and GI symptoms.

Imaging findings:

Radiograph:

• A soft tissue mass if it is large.
• A fat containing mass of fat density - the density of mass is lower than surrounding tissues.
• Characteristic calcification -Pop cord calcification or rim like or tooth or other bone (clavicle).

Ultrasonography:

• It has been reported as 98% of positive predictive value for ovarian dermoids.
• Compled mass with echogenic components.
• Mass is echogenic most of the times and producing "dirty acoustic shadowing"
• It may be purely cystic in 9-15% or purely solid in 10-31% cases.

CT scan:

• It demonstrates mass having fat, fluid and calcification (Tooth) as its contents.
• Rim like calcification, Tooth or other bone (clavicle) -Rokintasky protruberence.
• Fat-fluid levels may be seen.

MRI:

• The lesion shows hyperintense fat on T1 with hypointense fluid.
• Hyperintense on T2.
• Fat appears hypointense (suppressed) on STIR or T2 fat sat images.

Treatment:

• Surgical removal - May have risk of chemical peritonitis if ruptured.

Complications:

• Torsion.
• Rupture.
• Infection.
• Autoimmune hemolytic anemia - very rare.

Differential diagnosis:

• Benign or malignant ovarian tumor.
• Endometrioma.
• TO Abscess.
• Pedunculated uterine fibroid.
• Hydrosalpinx.
• Ectopic kidney.
• Pelvic kidney.

Renal angiomyolipoma-CT

Axial CT of kidneys in a 29 year old male showing small exophytic fat attenuation lesion in the left kidney (arrow) suggestive of angiomyolipoma.

Zoomed picture of the above showed image better shows the lesion.

Discussion:

Angiomyolipoma (AML) is the most common benign tumour of the kidney and is composed of blood vessels, smooth muscle cells and fat cells. It is strongly associated with tuberous sclerosis.

Imaging features:

Ultrasonography (USG) - Well defined hyper echoic lesion in the kidney. Hyperechogenecity is due to fat content of the lesion.

CT Scan: Well defined fat attenuation lesion as shown in our case. CT angiography may be helpful to identify the aneurysms which predict the fatal hemorrhage.

MRI - Hyperintense on both T1 and T2 weighted images due to its fat content and appears hypointense on fat suppressed T1 images. 

If the fatty tissue is scanty in-phase and out-phase images T1 weighted sequence is very helpful in identifying the fat component in the lesion, which is seen as loss of signal on out-phase images.

People with tuberous sclerosis needs yearly follow up  renal scans.

Treatment:

• If the lesion is < 4 cm - follow up imaging to look for the progression of the lesion.
• If it is > 4 cm or presence of aneurysm, needs to be treated with trans arterial embolisation or surgical excision. Embolising agents used are PVA (Polyvinyl alcohol) and absolute alcohol mixed with lipiodol. 

Renal cell carcinoma with Hiatus hernia-CT

Axial CT of kidneys in a 42 year old male showing large heterogeneously enhancing lesion in the left kidney with perinephric extension.

Axial section at the level of diaphragm of the same patient showing hiatus hernia (arrow) 

Duplex collecting system with ureterocele- CT Urography.

3D volume rendering maximum intensity projection image of CT urography in 29 year old male showing duplication of collecting system, upper and mid ureter on the left side (arrow head) with orthotopic ureterocele (arrow)

Duplex collecting system-CT Urography.

3D volume rendering maximum intensity projection image of CT Urography in 27 year old male showing duplication of collecting system, upper and mid ureter (arrow). Both the ureters are joining in their lower thirds (arrow head).

Papillary necrosis - CT Urography

Maximum intensity projection image of CT Urography in 32 year old male showing papillary necrosis in the right kidney with calyx cut off (arrow) due to old Koch’s

Renal parenchymal scarring-CT Urography

Coronal reformatted CT Urography images in a 32 year old male showing cortical scarring in bilateral kidneys due previous tuberculosis

Renal calculus-NCCT KUB (Stone protocol)

Axial and coronal reformatted non contrast CT images in a 32 year old female showing left renal calculus (arrows).

Renal cyst - CT

Axial and coronal reformatted CT images in a 36 year old male showing simple cortical cyst in the right kidney (Bosniak category I cyst).

Ureteric calculus-NCCT KUB (Stone protocol)

Axial and coronal reformatted non contrast CT images in a 41 year old showing right ureterovesical junction calculus (arrows).

Non contrast CT in multi slice CT (stone protocol) is the modality of choice for the diagnosis of ureteric calculus.

Fibromuscular dysplasia-CT Renal Angiography.

Volume rendered CT angiography image in 25 year old male scheduled for donor nephrectomy showing irregularity (string of beads) in the bilateral renal arteries (arrows) more so on the right side with aneurysm (arrow head) in one of the distal lobar renal artery branch.

Renal artery stenosis

Thick oblique axial and oblique coronal maximum intensity projection CT images in a 48 year old male donor scheduled for laparoscopic nephrectomy showed renal artery stenosis at the origin on the left side (arrow) with calcific focus.

Late confluence of left renal vein with Large gonadal vein draining the left renal vein

Thick oblique coronal maximum intensity projection CT image in a 46 year old female donor scheduled for laparoscopic nephrectomy showed late confluence of the left renal vein tributaries with large left gonadal vein (arrow) draining inferior tributary of renal vein (arrowhead). 

It is very important to identify this gonadal vein to prevent complication during laparoscopic nephrectomy.

Renal vein variants- Duplicated left inferior vena cava

Thick oblique sagittal maximum intensity projection CT images in a 26 year old female donor scheduled for donor nephrectomy showed duplication of inferior venacava (arrow).

Renal vein variants-Double renal vein

Thick maximum intensity projection CT image in a 41 year old female donor scheduled for donor nephrectomy showing double renal vein on the right side (arrows). Incidentally note multiple calcified gall stones (arrow head).

Renal vein variants-Retroaortic vein

Axial and thick maximum intensity projection CT images in a 46 year old female donor scheduled for donor nephrectomy showing retroaortic left renal vein (arrows) and double renal vein on the right side (arrow head).

Discussion:

Most common is multiple renal veins, seen in approx 15-30% of individuals. 

The most common anomaly of the left renal venous system is the circumaortic renal vein, seen in up to 17% of patients 

I. There are two common variants of the circumaortic vein: 

1. The most common variant (approximately 75% of cases), one renal vein at the renal hilum subsequently divides before entering the inferior vena cava. 

2. The less common variant, two distinct veins originate from the renal hilum.

II. A less common venous anomaly is the complete retroaortic renal vein, seen in 3% of patients. Here, the single left renal vein courses posterior to the aorta and drains into the lower lumbar portion of the inferior venacava.

Alternatively, the retroaortic renal vein can drain into the iliac vein.

Renal artery variants- High origin of renal artery

Volume rendered CT angiography image in a 26 year old male donor scheduled for donor nephrectomy showing abnormally high origin (D11 level) of the right renal artery. It is important to indentify the level of origin for the operating surgeon.

Volume rendered CT angiography image in another person aged 46 year old scheduled for donor nephrectomy showing abnormally high origin (D12 level) of the right renal artery.

Renal artery variants- early branching

Volume rendered CT angiography images in a 34 year old male donor scheduled for donor nephrectomy showing early branching (<2 cm) on the right side (arrow).

Discussion:

Branching of the renal artery at a distance of less than 1.5/2 cm from its origin is early branching.

A large early branch from the renal artery can result in complications during the laparoscopic donor nephrectomy and during the renal transplantation.

CT Renal angiography - Normal

 3D volume rendering image showing normal bilateral renal arteries and aorta

Coronal curved multi planar reformatted image showing normal bilateral renal veins.

Renal arteries: 

• Single renal arteries bilaterally that originates from the abdominal aorta at the level of L3 below the origin of superior mesenteric artery. 
• It is important to identify the variants of the renal arteries.

Renal veins:

• Usually lies anterior to the renal artery at the renal hilum. 
• Left is 3 times longer than right. 
• Left – 6-10 cm length- courses anterior to aorta. 
• Right – 2-4 cm in length. The left renal vein receives left gonadal, left adrenal and left lumbar tributaries.