A comprehensive summary of the points that are prone to missed diagnosis in cranial MR

Intracranial lesions

Left temporal meningioma, in the four sequences of T1WI, T2WI, Flair, DWI are very close to the signal
of the brain parenchyma.
Such a small meningioma has a very high missed diagnosis rate on MR plain scanning, and the way to avoid missed diagnosis is to do a good job of brain anatomy, and then quickly pinch the sulci when watching the film, and focus on the area
where the groove changes in morphology.

Small infarct on
the left side of the medulla oblongata.
This kind of spotted infarct is also very common, and the patient's symptoms are generally not obvious, and I have missed it twice
.
Small infarcts are more common around the brainstem and lateral ventricles, and cerebral cortex areas are generally rare
.
Therefore, careful observation of key areas can reduce the missed diagnosis
of such diseases.

The missed diagnosis rate of arachnoid cyst (red arrow) anterior to the temporal pole is also relatively high, especially in elderly patients, often mistaken for an enlarged subarachnoid space, and careful observation can find that the right temporal lobe is compressed, and the sulci occlusion (green arrow) is more obvious
compared with the healthy side (blue arrow).

Ventricular and cistern lesions

The cystic mass of the right ventricle body (red arrow), the overall signal is consistent with cerebrospinal fluid, the edge of the lesion is shown, and the hyaline septum is slightly displaced
.

The gray matter is displaced and the patient has a history of
previous epilepsy.
Ectopic gray matter nodules (red arrows) can be seen in the anterior corner of the right ventricle and the posterior corner of the left ventricle, which are consistent with the gray matter signal under the cerebral cortex (green arrow), and patients with gray matter ectopia are often accompanied by epilepsy symptoms
.

Transparent septum is lacking, and I have missed cases
myself.
There are many normal images on it for comparison and observation
.

This case of moyamoya disease was described in a previous article (a point that is very easy to miss in non-contrast brain MR scanning!).
has already mentioned it, take it out and review it
again.

In patients with meningitis, abnormally increased vascular shadows (red arrows) can be seen in the anterior bridge pool, and normal people's prepontopontine pool due to artifacts generated by cerebrospinal fluid flow can also be seen in the pool flocculent low signal (green arrow), but it is not as obvious as the right patient, which is more difficult to observe, just like observing whether the patient has liver enlargement on abdominal CT, which requires an experience accumulation process
.
The yellow arrow refers to the basilar artery, and the blue arrow refers to the trigeminal nerve
.

Skull lesions

Cystic lesions (red arrows) in the left petrous apex, the patient is unoperated, and the pathology is unknown
.
MR does not show good bone structure, so many readers will ignore the observation of intracranial bone lesions, many intracranial lesions, such as trigeminal schwannoma, nasopharyngeal carcinoma, etc.
will cause bone destruction in the petrous part of the temporal bone (red marked area), so you should pay more attention
here.
The yellow arrow refers to the auditory nerve and inner ear structures
.

Abnormal proliferation of sphenoid bone fibers (red arrow), characteristic cystic areas (yellow arrows)
visible inside the lesion.
Lesions of the sphenoid bone are more difficult to identify on MR because the sphenoid bone is located at the base of the skull, where bone, muscle, fat and other tissue components are mixed, resulting in a very messy
appearance under normal circumstances.
Don't rush, learn
slowly.

Abnormal proliferation of bone fibers
in the left parietal bone.
The lesion is located in the left parietal plate barrier area, the local bone is swelling, the lesion edge osteosclerosis, obvious low signal (red arrow), large flaky flocculent structure (yellow arrow) and focal glassy degeneration area (green arrow)
can be seen inside.

In patients with postoperative breast cancer, the bone signal of the central spine is abnormal, and follow-up confirmation is bone metastasis
.
With the increasing number of tumor patients, the examination of cranial MR examination to exclude brain metastases is also gradually increasing, do not only focus on finding metastases in the brain, the surrounding structures should also be observed
.

Another thing to observe in the sagittal position is the height of the dentate process, which is often caused by depressed skull base (the red line is the Qian's line).

Subscalp lesions

Subscalp hemangioma and sebaceous adenoma are very common, and it is easy to miss the diagnosis, although the clinical significance is small, but it should still avoid missing the diagnosis, after all, everyone's situation is difficult to say ~

Right frontal subscalpal hemangioma
.
The patient is an 11-year-old female, which is the most common age of the disease, and if this nodule is missed, I am afraid that there will be trouble
.

Scalp hematoma (acute stage), lesions are hypointense
on both T1WI and T2WI.

Cavernous sinus, CPA area lesions

The left internal carotid cavernous sinus segment aneurysm with thrombosis (red arrow), the green arrow is the beginning of the cavernous sinus segment, and the yellow arrow points to the anterior bed process, an important anatomical sign of internal carotid artery segmentation (internal carotid artery segmentation can refer to the previous article Internal Carotid CTA segmentation (ultra-practical)).

In addition to aneurysms around the cavernous sinus, mass lesions are also common, such as meningiomas, schwannomas, extracerebral cavernous hemangiomas, etc
.

The right CPA region (pontocerebellar angle area) occupies (red arrows), shows isolow signal T1WI and T2WI, and the adjacent auditory nerve shows OK (yellow arrows), thus predisposing to the diagnosis of meningioma
.
This patient's medical history does not complain of hearing impairment, so usually write a report and do not wait until the patient has hearing impairment to observe the auditory nerves
on both sides.

Right CPA area acoustic neuroma (red arrow).

Some use 1.
5T MR, the display of sellar area and subcurtain structure will be less than ideal, coupled with the development of the pontocerebellar angle cistern in this case is relatively narrow, can not set off the lesion well, at this time it is easy to cause missed diagnosis
.

It is also relatively common for vertebrobasilar arteries to be compressed due to the compression of the adjacent medulla oblongata, although it is not a missed diagnosis, but the author believes that this pathological change should still be reflected in the report
.

Lesions of the eye, ear, nose and throat

The right side is retinal exfoliation (red arrow), and the back of the eye is the detached retinal tissue and blood-collecting area; On the left is a cataract patient, and the uniform increase of lens signal in the affected eye on T2WI is its characteristic performance
.

Left mastoiditis (red arrow), right mastoid is well vaporized, does not contain inflammation, and has no signal on MR (green arrow).

In some patients, mastoid sinus gasification is poor or the lateral part adjacent to the temporal bone is too thick and there is more yellow bone marrow, which can be highly intensed on T2WI, especially when the mastoid development on both sides is asymmetrical, it is easy to misdiagnose mastoiditis
.
Note that the large flowing vascular shadow (green arrow) on the right is the internal jugular vein
.

Elderly male patients, complaining of dizziness, undergo craniocerebral MR to find nasopharyngeal carcinoma
.
I have also seen such a large missed diagnosis of nasopharyngeal cancer, which is mainly caused by
poor reading habits.
Note that the parapharyngeal space on either side of the patient is clear, indicating that the lesion has not begun to invade the surrounding tissues extensively, in which case the patient is often unable to provide valuable historical information
.

Head and neck lesions

The parotid gland is not visible on axial sequences, but can be observed on sagittal Flair sequences (red-coded areas).

In this case, the right parotid Voshing tumor (red arrow) is located between
the mastoid (yellow arrow) and the mandibular branch.

Another overlooked site in the sagittal position is the thyroid gland, which in this case is enlarged and the signal is uniform, and further ultrasonography
should be recommended.

Full summary: After reading this article, will you be surprised to find that there are so many structures that need to be observed in the cranial MR scan! Do you instantly feel that you may have missed a large number of lesions before? It doesn't matter, through the above summary of common missed cases, you can combine your own actual situation and formulate a correct reading order for yourself, so that you can effectively avoid missed diagnosis
in future work.