Putty kidney

43 year old female came for USG evaluation of abdomen to rule out metastasis from carcinoma breast. This USG showing calcified mass in whole of the left kidney witch is maintaining the renal contour with posterior acoustic shadow suggestive of putty kidney.

Putty kidney is an end stage of infection with tuberculosis in the genitourinary tract, calcification may entirely outline a nonfunctional kidney.The radiologic appearance of this condition, completely calcified kidney which is associated with autonephrectomy, has been described as the putty kidney. It is very common to see the radiographic and CT appearance of putty kidney but unusual to see the USG features of putty kidney.

MEDIASTINAL NEUROBLASTOMA

One year old female baby came with history of persistent cough, difficulty in breathing and stridor. Baby also had weight loss and sometimes mild fever. Routine hematological investigations were normal. Chest radiograph and contrast enhanced CT scan showed below mentioned findings

Figure 1 a) Radiograph frontal view showing homogenous opacity lesion in the right upper and mid zone with broad base towards mediastinum. The lesion is causing shift of mediastinum and trachea to the contralateral side and compressing the trachea just above the carina (arrow head). The lesion is extending above the clavicle (cervico-thoracic sign) and erosion of posterior end of third and fourth ribs (Long arrow). C) Contrast enhanced CT scan axial section mediastinal window showing heterogeneously enhancing mass lesion in the right posterior mediastinum extending to middle mediastinum causing compression of the trachea. The lesion is showing multiple small foci of calcification (black arrows in fig c).

Discussion:

Primary mediastinal neuroblastoma accounts for 14% of all neuroblastomas. Common location is posterior mediastinum, where they arise from paravertebral sympathetic chain. Patient commonly present with chest pain, cough and respiratory distress due to airway obstruction. Chest radiograph is the initial radiological investigation to be done in such patients. It demonstrates homogenous opacity mass in the mediastinum. If the tumor is large, there may be extrinsic compression and displacement of trachea and main bronchus with mediastinal shift (fig a-c). Rib erosion and asymmetrical widening of inercostal spaces may be seen on radiograph. Intraspinal extension may be seen as loss of vertebral height with widening of neural foramina on lateral radiograph. Approximately 50% of the lesions show calcification on radiograph.

CT scan is usually done to confirm the presence of lesion, and it also helps to define the location and extent of lesion, adjacent organ involvement, or vascular involvement. CT demonstrates calcification in up to 90%. The lesion characterization has become better with the advent of multiplanar image reconstructions in MDCT. However MR imaging is the investigation of choice for better characterization and demonstration of full extent of mass, extradural intraspinal extension and chest wall invasion. The advantages of MR over CT are its direct multiplanar imaging and better contrast resolution, which can allow differentiation of vascular from non vascular lesions without the aid of intravenous contrast agent. MR is very often used to evaluate tumor involving spine and spinal canal.

Teaching point:

Radiograph is the initial investigation to be done in the mediastinal masses and one should be able to identify the lesion and arrive at differential diagnosis. CT scan and MRI are done to confirm the lesion, location, extent, adjacent organ involvement or vascular involvement and intraspinal extension.

Congenital CMV infection

CT scan of 5 month old male showing paucity of white matter, gross hydrocephalus with periventricular calcification and patchygyria suggestive of congenital TORCH infection most likely CMV infection.

Cytomegalovirus infection may be acquired prenatally or perinatally. Signs at birth, if present, are intrauterine growth restriction, prematurity, microcephaly, jaundice, petechiae, hepatosplenomegaly, periventricular calcifications, chorioretinitis, and pneumonitis. Later in infancy, signs are pneumonia, hepatosplenomegaly, hepatitis, thrombocytopenia, and atypical lymphocytosis. Diagnosis is by virus isolation or serology. Treatment is supportive. Parenteral ganciclovir can prevent hearing deterioration, but its use remains controversial.

Differential diagnosis: TORCH infection, Congenital lymphocytic choriomeningitis, Pseudo-TORCH syndrome, Tuberous sclerosis.

Pseudo-torch syndrome: A rare genetic syndrome characterized by a small head, eye disease and brain abnormalities.

Medullary nephrocalcinosis

Ultrasonography of both kidneys in 9 year old female showing multiple areas of increased echogenicity involving all of the medullary pyramids consistent with nephrocalcinosis. The renal cortex is normal in echogenicity. There is no evidence of hydronephrosis.

Medullary nephrocalcinosis refers to calcification in the medullary pyramids rather than the renal collecting system. It is caused by a number of processes, but the three most common are : hyper-parathyroidism medullary , renal tubular acidosis and sponge kidney (tubular ectasia). Medullary nephrocalcinosis is usually associated with hypercalcuria and often with hypercalcemia. Primary hyperparathyroidism and distal renal tubular acidosis account for over 60% of these cases. The remaining 40% of cases are due to a variety of other causes of hypercalciuria, including milk-alkali syndrome, Cushing's syndrome, bony metastases, hyperthyroidism, hypothyroidism, sarcoidosis, furosemide therapy, and in this case, vitamin D therapy.

Ultrasonography is more sensitive than conventional radiography and CT and sonography is unusually sensitive in detecting this condition, and the sonographic changes predate any visible calcification and are generally more dramatic than the abnormalitie seen on CT. Nephrocalcinosis may affect some or ail of the pyramids. The deposits of calcium phosphate and calcium oxalate in the interstitium of the renal pyramids reverse the sonographic appearance of the normal kidneys. The pyramids are normally hypoechoic relative to the cortex. In its early stages it causes increased medullary echogenicity at the periphery of the pyramids and eventually involves the entire pyramids. With progressive calcification, shadowing begins. A regular arrangement of hyperechoic pyramids are seen which may shadow if large calcified foci are present, but not if the foci are numerous and tiny, as they are smaller than the beam width. Less frequently, calcification is seen in the renal cortex.

Cardiac hydatid cyst

CT scan of 58 year old male patient showing large well defined well capsulated hypodense lesion seen in the myocardium of the left ventricle with multiple daughter cysts within suggestive of hydatid cyst.

• Hydatid disease is a parasitic infection caused by larvae of Echinococcus granulosus, which is still endemic in many sheepraising countries.
• Hydatid cysts can be located in various tissues, although they are most common in the liver (50–70% of cases) and the lung (20–30% of cases) in humans.
• Cardiac involvement in hydatid disease is uncommon, constituting only 0.5–2% of all cases of hydatidosis.
• Heart involvement - LV – 60%, RV – 10%, pericardium – 7%, pulm Artery – 6%, left atrial appendage – 6%, and interventricular septum is rare – 4%.
• Cardiac involvement occurs by invasion of the myocardium - Through coronary circulation or pulmonary vein from rupture of pulm cysts in to vein.

• Signs and Symptoms •No symptoms due to its latency and slow growing nature unless it is situated in critical site. •Signs and symptoms are extremely variable and directly related to location and size of the cysts. •Precordial pain is the most common symptom and is most often vague and does not resemble angina pectoris. •Sudden rupture of intracardiac cysts is a frightful complication and can cause acute pericarditis or tamponade, acute pulmonary hypertension by embolization of several scolices, systemic arterial embolization, and severe anaphylactic shock can be life thretening.

• Imaging - Echocardiography, CT, and MRI can show the cystic nature of the mass and its relation to the cardiac chambers •CT best shows wall calcification. •MRI depicts the exact anatomic location and nature of the internal and external structures and is the technique used for posttreatment follow-up.
• The appearance of a hydatid cyst on MRI is usually a characteristic oval lesion that is hypointense on T1-weighted images and hyperintense on T2-weighted images. •A typical finding on T2-weighted images is a hypointense peripheral ring, which represents the pericyst (a dense fibrous capsule from the reactive host tissue). •A variety of tumors in the heart and a congenital pericardial cyst must be considered in the differential diagnosis; however, the multivesicular nature of the cystic mass and membrane detachment indicate the true diagnosis.
• The cysts may be single or multiple, uni or multiloculated, and thin or thick walled. •More specific signs are •Cyst wall calcification. •Presence of daughter cysts and Membrane detachment.
• •Surgery remains the treatment of choice in the management of hydatid disease. •Although antihelminthic drugs have been used in the preoperative and postoperative periods since 1977, extirpation of the lesion under cardiopulmonary bypass is recommended.
• To conclude CT and MRI are helpful for localizing and defining the morphologic features of hydatid cysts. •Specific signs include calcification of the cyst wall, presence of daughter cysts, and membrane detachment. •CT best shows wall calcification, whereas MRI depicts the exact anatomic location and nature of the internal and external structures.

Antenatal diagnosis Chiary II malformation - Fetal MRI

Gravida two female with previous history of abortion came for fetal MRI to ruleout congenital malformation showing lumbosacral myelomeningocele (arrow in first and third image), tonsillar herniation and corpus callosum dysgenesis (arrow in second image). features suggestive of Chiary 2 malformation.

The Austrian pathologist Hans Chiari in the late 1800s described seemingly related anomalies of the hindbrain, the so called Chiari malformations I, II and III. Later, other investigators added a fourth (Chiari IV) malformation.

Types include

Type I - Is generally asymptomatic during childhood, but often manifests with headaches and cerebellar symptoms. Herniation of cerebellar tonsils

Type II - Usually associated with myelomeningocele leading to partial or complete paralysis below the spinal defect. Abnormal development of the cerebellar vermis andmedulla oblongata occur, and they both descend into the foramen magnum. Hydrocephalus is frequently present.

Type III - Type II associated with with an encephalocele.

Type IV - Lack of cerebellar development.

The Chiari II malformation is a complex congenital malformation of the brain, nearly always associated withmyelomeningocele. This condition includes downward displacement of the medulla, fourth ventricle, and cerebellum into the cervical spinal canal, as well as elongation of the pons and fourth ventricle, probably due to a relatively small posterior fossa.

MRI Brain in Carbon monoxide poisoning

18 year old boy came with dizziness, head ache, nausea and loss of conciousness. Gives history of overnight sleeping in the room with burning charcoal heater. MRI FLAIR and T2 (a&b) image showing bilateral symmetrical hyperintensities in globus pallidi. (c&d) diffusion weighted images showing no restriction. features consistent with carbon monoxide poisoning.

In carbon monoxide poisoning, the gas crosses the alveolar capillary membrane and binds strongly with heme containing compounds. The toxicity is due to hypoxia and carbon monoxide mediated damage at the cellular level. Globus pallidus and pars reticulata of substantia nigra are the regions of the highest iron content in the brain. Carbon monoxide directly binds to heme iron in these two regions.

MRI in acute carbon monoxide poisoning, the abnormalities are detected as T2 hyperintensities. Lesions are in the basal ganglia involving the globus pallidus, putaman, caudate nucleus with other areas such as periventricular white matter, subcortical white matter, cerebral cortex, medial temporal lobe (hippocampus) and cerebellum. Diffusion Weighted Imaging(DWI) and MR Sprectroscopy are also useful. Diffusion weighted imaging shows diffuse hyperintensity in periventricular white matter and semiovale, splenium of corpus callosum, internal capsules, and brainstem, with moderately decreased apparent duffusion co-efficient (ADC) values. In the globus pallidus, the ADC values are rather increased, with low signal intensities on DWI as seen in this case. The MRS (MR Spectroscopy) demonstrates decreases n-acetyl aspartase in bilateral basal ganglia.

Focal Nodular Hyperplasia of Liver - CT and MRI

MRI of 30 year old female T1 weighted image showing well defined slightly hypointense lesion with central hypointense scar which is showing slightly hyperintense on T2 WI. In venous phase the lesion is showing homogeneous contrast enhancement (arrow). In delayed phase image there is enhancement of scar.

CT of another 28 year old female showing well defined showing arterial enhanging lesion in the left lobe of liver with central non enhancing scar. On venous phase image the lesion shows homogeneous contrast enhancement. In delayed phase image there is enhancement of scar.
Discussion:

FNH is considered a non-neoplastic, hyperplastic response to a congenital vascular malformation. Histologically, FNH is not a tumor and consists of benign-appearing hepatocytes occurring in a liver that is otherwise normal (i.e. no cirrhosis).
On CT scan the FNH are hypervascular lesions with homogeneous enhancement in arterial phase and hypodense central scars in arterial and venous phase, which enhance in the equilibrium phase. This is characteristic of FNH.
On MR typical FNH is slightly hypointense on T1WI and slightly hyperintense on T2WI. The scar is somewhat hyperintense on T2. The enhancement is as we expect with 'capillary blush' with a scar that enhances late in the equilibrium phase. We need to differentiate fibrolammellar carcinoma (FLC) of liver from FNH as the imaging findings are almost similar except for few differentiating points. The central scar is hyperintense on T2 in FNH where as it is Hypo in FLC. Scar enhances in delayed phase of contrast study in FNH where as it will not enhances in FLC. May see calcification in FLC and not in FNH.

Osteosarcoma of Sternum

CT scan and MRI of 40 year old male came with swelling and pain in the sternum since 3 months shows large destructive soft tissue mass lesion in the body of sternum having osteoid matrix. The lesion is extending anteriorly in the subcutanesous region, psoteriorly in to mediastinum abutting large vessels. We can better appreciate the sternal destruction in SSD image. MR T2 weighted image shows hyperintense signal throughout the lesion. Histopathology proved to be osteosarcoma.

The primary sternal tumors are quite rare. The most commonly occurring malignant tumor in sternum is chondrosarcoma and occurrence of osteosarcoma in sternum is extremely rare. The most common tumors of sternum are the metastases of lung, renal or thyroidal malignancies. CT may show lytic, mixed or sclerotic pattern and it is observed as an expansile mass lesion with irregular borders, and the lesion invades bone marrow by destroying the cortex. MRI clearly demonstrates the extent of the lesion and characterization of the lesion.

Occular Metallic Foreign body

17 year old male CT coronal, axial and coronal bone window showing metallinc foreign body in the right globe adherent to lateral wall.
Metallic foreign body in another patient in right orbit on radiograph (arrow). CT scan axial section of the same patient showing foreign body just posterior to the limbus which is extra occular.

Intraocular foreign bodies (IOFBs) are rather variable in presentation, outcome, and prognosis. With increased awareness and advanced surgical techniques, the outcome and the prognosis for these potentially devastating injuries have substantially improved.

CT scans are the imaging study of choice for IOFB localization. A helical CT scan is the most efficient method to establish a diagnosis. Helical CT scans have a very high identification rate. With conventional CT scans, cuts of 0.5 mm are advised. With the advent of MDCT the role of radiologist has become easier in identification and diagnosis of occular foreign body. Plain x-ray is useful if a metallic IOFB is present and a CT scan is unavailable. MRI is generally not recommended for metallic IOFBs. Ultrasound is a useful tool in localizing IOFBs, and its careful use is possible even if the globe is still open; alternatively, intraoperative use after wound closure can be attempted. The ultrasound biomicroscope may help with IOFBs in the anterior segment.

Pheochromocytoma

MRI abdomen of 14 year old male patient came with uncontrolled hypertension with raised urinary catecholamines showing well defined focal soft tissue intensity mass in the left supra renal gland having intensely hyperintense on T2 W image and hypointense on T1W image. Features are consistent with pheochromocytoma.

Pheochromocytomas are rare but treacherous catecholamine-producing tumors, which if missed or not properly treated, will almost invariably prove fatal. Prompt diagnosis is, therefore, essential for effective treatment, usually by surgical resection. The manifestations are diverse and the tumor can mimic a variety of conditions, often resulting in either erroneous diagnoses or a delayed diagnosis. Imaging is very essential for accurate diagnosis.

Pheochromocytomas are extra adrenal (10%), multicentric (10%), bilateral (5%), and malignant (10%)..Size is variable from 1-20 cm.The treatment is surgical excision of tumor, which is curative in all cases. The initial imaging findings in benign and malignant pheochromocytomas are nearly identical. Only the presence of metastasis can clearly define a lesion as malignant. On CT it appears as round or oval discrete mass with homogenous density. Similar findings have been noted in the present case. Central necrosis, calcification and cystic changes may be present in minority of cases. These vascular lesions enhance uniformly after administration of contrast material. MR is also excellent for evaluating intraadrenal pheochromocytoma.On T1, mass has intensity similar to or slightly less than solid organs. OnT2 lesion is hyper intense as result of their long T2 time. Sometimes adrenal metastases also present overlapping imaging findings. Combination of MIBG,CT and MRI scanning is definitive in the diagnosis of pheochromocytoma.

Focal Pyelonephritis

40 year old male patient came to emergency with history of right lumbar pain and fever, USG Doppler of right kidney shows focal hypoechoic area in upper pole with small anechoic area within. CT scan of the same patient showwed focal hypoenhancing lesion in upper pole of right kidney with small non enhancing area within. These features are suggestive of focal pyelonephritis with evolution of abscess.

Acute focal pyelonephritis (AFP) is a variant of pyelonephritis in which single or multiple discrete areas show changes of inflammation. The sonographic appearances of AFP are varied and can be echogenic, echopoor or of mixed echogenicity, but are typically described as being echopoor. CT typically shows focal hypoenhancing areas. Imaging is done mainly to identify the complications like intra renal and peri renal abscess.

Wilms' tumour with IVC and right atrial thrombus

CT scan of 15 year old female shows large mass lesion (arrow head) in the left kidney pushing the aorta and IVC to right side and tumour is extending in to left renal vein (short arrow), IVC and into the right atrium (long arrow).

Vascular extension to the vena cava occurs in 4% of Wilms tumor cases and can reach the right atrium in up to 1%. When this happens the thrombus is usually not adherent to the vessel wall, and there is blood flow around it. Preoperative chemotherapy can cause thrombus regression and even resolution. If the thrombus persists after chemotherapy, surgery will be a challenge. On the other hand, if the thrombus invades the vessel wall, its removal may not be feasible. In this situation cavectomy is a good surgical strategy because it provides complete resection. The prerequisite for cavectomy is the absence of blood flow in the vena cava on preoperative Doppler ultrasonography.

Colon Lipoma

44 year old male presented to gastroenterology clinic complaining loose stools . Upper GI endoscopy was normal. Patient was referred for CT enteroclysis. The images revealed 4X3.5 cm well defined intralumnal fat attenuation lesion seen in the desecnding colon attached to the lateral wall. The findings are consistent with colonic lipoma.

Colon lipoma was described initially by Bauer in 1757. The incidence was estimated to be about 0.26%. colon lipoma constituted 0.3% of the cases treated for colorectal diseases and 1.8% of the cases of benign colorectal tumor during the same period. Elders are more likely to be involved. Most of the lesions were located at the right side of large bowel, accounting for nearly 90% of cases. The majority of colon lipomas presented as single while only 10% of cases were multiple. Most lipomas are submucosal while some are subserosal location. Some are sessile and some pedunculated. CT scan features of lipoma include well defined well capsulated fat attenuation lesion with not much enhancement are diagnostic of lipoma. MR shows hyperintense lesion on T1 and T2 W imagea and loss of signal in fat saturated images. Treatment is mainly by colonoscopic resection if the lesion is pedunculated and surgery if it is sessile.

The Double Posterior Cruciate Ligament (PCL) Sign - Bucket handle tear of medial meniscus.

25 year old young male soccer player presented with a 1 week history of his right knee locking and was not allowed to extend completely as he walked. On physical examination, the left knee appeared minimally swollen but did not feel warm. There was an audible click when the flexed left knee was extended while varus pressure was applied (McMurray test). MRI was performed, Sagittal fat saturated T2 weighted image of the right knee through the intercondylar notch reveals a thin linier fragment of torn meniscus which appears as a low-signal intensity longitudinally oriented band (arrow) lying beneath and parallel to the posterior cruciate ligament (arrow head), creating a double cruciate configuration, referred to as the double posterior cruciate ligament (PCL) sign. The abnormal hyperintensity in keen joint space and supra patellar region is joint effusion. Patient underwent arthroscopic repair of the torn ligament.

The double PCL sign is associated with bucket handle tears of medial meniscus, At MRI this sign relates to the peripheral (bucket) portion of the meniscus and the displaced inner fragment (handle) portion. Identifying the bucket-handle tears early is critical because, depending on how peripheral and complex the tear is, any delay can compromise the chances for repair. If the tear is not reduced, the meniscal fragment risks further maceration.